fs/proc/base.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/proc/base.c
   4  *
   5  *  Copyright (C) 1991, 1992 Linus Torvalds
   6  *
   7  *  proc base directory handling functions
   8  *
   9  *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
  10  *  Instead of using magical inumbers to determine the kind of object
  11  *  we allocate and fill in-core inodes upon lookup. They don't even
  12  *  go into icache. We cache the reference to task_struct upon lookup too.
  13  *  Eventually it should become a filesystem in its own. We don't use the
  14  *  rest of procfs anymore.
  15  *
  16  *
  17  *  Changelog:
  18  *  17-Jan-2005
  19  *  Allan Bezerra
  20  *  Bruna Moreira <[email protected]>
  21  *  Edjard Mota <[email protected]>
  22  *  Ilias Biris <[email protected]>
  23  *  Mauricio Lin <[email protected]>
  24  *
  25  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  26  *
  27  *  A new process specific entry (smaps) included in /proc. It shows the
  28  *  size of rss for each memory area. The maps entry lacks information
  29  *  about physical memory size (rss) for each mapped file, i.e.,
  30  *  rss information for executables and library files.
  31  *  This additional information is useful for any tools that need to know
  32  *  about physical memory consumption for a process specific library.
  33  *
  34  *  Changelog:
  35  *  21-Feb-2005
  36  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  37  *  Pud inclusion in the page table walking.
  38  *
  39  *  ChangeLog:
  40  *  10-Mar-2005
  41  *  10LE Instituto Nokia de Tecnologia - INdT:
  42  *  A better way to walks through the page table as suggested by Hugh Dickins.
  43  *
  44  *  Simo Piiroinen <[email protected]>:
  45  *  Smaps information related to shared, private, clean and dirty pages.
  46  *
  47  *  Paul Mundt <[email protected]>:
  48  *  Overall revision about smaps.
  49  */
  50
  51 #include <linux/uaccess.h>
  52
  53 #include <linux/errno.h>
  54 #include <linux/time.h>
  55 #include <linux/proc_fs.h>
  56 #include <linux/stat.h>
  57 #include <linux/task_io_accounting_ops.h>
  58 #include <linux/init.h>
  59 #include <linux/capability.h>
  60 #include <linux/file.h>
  61 #include <linux/fdtable.h>
  62 #include <linux/generic-radix-tree.h>
  63 #include <linux/string.h>
  64 #include <linux/seq_file.h>
  65 #include <linux/namei.h>
  66 #include <linux/mnt_namespace.h>
  67 #include <linux/mm.h>
  68 #include <linux/swap.h>
  69 #include <linux/rcupdate.h>
  70 #include <linux/kallsyms.h>
  71 #include <linux/stacktrace.h>
  72 #include <linux/resource.h>
  73 #include <linux/module.h>
  74 #include <linux/mount.h>
  75 #include <linux/security.h>
  76 #include <linux/ptrace.h>
  77 #include <linux/tracehook.h>
  78 #include <linux/printk.h>
  79 #include <linux/cache.h>
  80 #include <linux/cgroup.h>
  81 #include <linux/cpuset.h>
  82 #include <linux/audit.h>
  83 #include <linux/poll.h>
  84 #include <linux/nsproxy.h>
  85 #include <linux/oom.h>
  86 #include <linux/elf.h>
  87 #include <linux/pid_namespace.h>
  88 #include <linux/user_namespace.h>
  89 #include <linux/fs_struct.h>
  90 #include <linux/slab.h>
  91 #include <linux/sched/autogroup.h>
  92 #include <linux/sched/mm.h>
  93 #include <linux/sched/coredump.h>
  94 #include <linux/sched/debug.h>
  95 #include <linux/sched/stat.h>
  96 #include <linux/posix-timers.h>
  97 #include <linux/time_namespace.h>
  98 #include <linux/resctrl.h>
  99 #include <linux/cn_proc.h>
 100 #include <trace/events/oom.h>
 101 #include "internal.h"
 102 #include "fd.h"
 103
 104 #include "../../lib/kstrtox.h"
 105
 106 /* NOTE:
 107  *      Implementing inode permission operations in /proc is almost
 108  *      certainly an error.  Permission checks need to happen during
 109  *      each system call not at open time.  The reason is that most of
 110  *      what we wish to check for permissions in /proc varies at runtime.
 111  *
 112  *      The classic example of a problem is opening file descriptors
 113  *      in /proc for a task before it execs a suid executable.
 114  */
 115
 116 static u8 nlink_tid __ro_after_init;
 117 static u8 nlink_tgid __ro_after_init;
 118
 119 struct pid_entry {
 120         const char *name;
 121         unsigned int len;
 122         umode_t mode;
 123         const struct inode_operations *iop;
 124         const struct file_operations *fop;
 125         union proc_op op;
 126 };
 127
 128 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 129         .name = (NAME),                                 \
 130         .len  = sizeof(NAME) - 1,                       \
 131         .mode = MODE,                                   \
 132         .iop  = IOP,                                    \
 133         .fop  = FOP,                                    \
 134         .op   = OP,                                     \
 135 }
 136
 137 #define DIR(NAME, MODE, iops, fops)     \
 138         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 139 #define LNK(NAME, get_link)                                     \
 140         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 141                 &proc_pid_link_inode_operations, NULL,          \
 142                 { .proc_get_link = get_link } )
 143 #define REG(NAME, MODE, fops)                           \
 144         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 145 #define ONE(NAME, MODE, show)                           \
 146         NOD(NAME, (S_IFREG|(MODE)),                     \
 147                 NULL, &proc_single_file_operations,     \
 148                 { .proc_show = show } )
 149 #define ATTR(LSM, NAME, MODE)                           \
 150         NOD(NAME, (S_IFREG|(MODE)),                     \
 151                 NULL, &proc_pid_attr_operations,        \
 152                 { .lsm = LSM })
 153
 154 /*
 155  * Count the number of hardlinks for the pid_entry table, excluding the .
 156  * and .. links.
 157  */
 158 static unsigned int __init pid_entry_nlink(const struct pid_entry *entries,
 159         unsigned int n)
 160 {
 161         unsigned int i;
 162         unsigned int count;
 163
 164         count = 2;
 165         for (i = 0; i < n; ++i) {
 166                 if (S_ISDIR(entries[i].mode))
 167                         ++count;
 168         }
 169
 170         return count;
 171 }
 172
 173 static int get_task_root(struct task_struct *task, struct path *root)
 174 {
 175         int result = -ENOENT;
 176
 177         task_lock(task);
 178         if (task->fs) {
 179                 get_fs_root(task->fs, root);
 180                 result = 0;
 181         }
 182         task_unlock(task);
 183         return result;
 184 }
 185
 186 static int proc_cwd_link(struct dentry *dentry, struct path *path)
 187 {
 188         struct task_struct *task = get_proc_task(d_inode(dentry));
 189         int result = -ENOENT;
 190
 191         if (task) {
 192                 task_lock(task);
 193                 if (task->fs) {
 194                         get_fs_pwd(task->fs, path);
 195                         result = 0;
 196                 }
 197                 task_unlock(task);
 198                 put_task_struct(task);
 199         }
 200         return result;
 201 }
 202
 203 static int proc_root_link(struct dentry *dentry, struct path *path)
 204 {
 205         struct task_struct *task = get_proc_task(d_inode(dentry));
 206         int result = -ENOENT;
 207
 208         if (task) {
 209                 result = get_task_root(task, path);
 210                 put_task_struct(task);
 211         }
 212         return result;
 213 }
 214
 215 /*
 216  * If the user used setproctitle(), we just get the string from
 217  * user space at arg_start, and limit it to a maximum of one page.
 218  */
 219 static ssize_t get_mm_proctitle(struct mm_struct *mm, char __user *buf,
 220                                 size_t count, unsigned long pos,
 221                                 unsigned long arg_start)
 222 {
 223         char *page;
 224         int ret, got;
 225
 226         if (pos >= PAGE_SIZE)
 227                 return 0;
 228
 229         page = (char *)__get_free_page(GFP_KERNEL);
 230         if (!page)
 231                 return -ENOMEM;
 232
 233         ret = 0;
 234         got = access_remote_vm(mm, arg_start, page, PAGE_SIZE, FOLL_ANON);
 235         if (got > 0) {
 236                 int len = strnlen(page, got);
 237
 238                 /* Include the NUL character if it was found */
 239                 if (len < got)
 240                         len++;
 241
 242                 if (len > pos) {
 243                         len -= pos;
 244                         if (len > count)
 245                                 len = count;
 246                         len -= copy_to_user(buf, page+pos, len);
 247                         if (!len)
 248                                 len = -EFAULT;
 249                         ret = len;
 250                 }
 251         }
 252         free_page((unsigned long)page);
 253         return ret;
 254 }
 255
 256 static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf,
 257                               size_t count, loff_t *ppos)
 258 {
 259         unsigned long arg_start, arg_end, env_start, env_end;
 260         unsigned long pos, len;
 261         char *page, c;
 262
 263         /* Check if process spawned far enough to have cmdline. */
 264         if (!mm->env_end)
 265                 return 0;
 266
 267         spin_lock(&mm->arg_lock);
 268         arg_start = mm->arg_start;
 269         arg_end = mm->arg_end;
 270         env_start = mm->env_start;
 271         env_end = mm->env_end;
 272         spin_unlock(&mm->arg_lock);
 273
 274         if (arg_start >= arg_end)
 275                 return 0;
 276
 277         /*
 278          * We allow setproctitle() to overwrite the argument
 279          * strings, and overflow past the original end. But
 280          * only when it overflows into the environment area.
 281          */
 282         if (env_start != arg_end || env_end < env_start)
 283                 env_start = env_end = arg_end;
 284         len = env_end - arg_start;
 285
 286         /* We're not going to care if "*ppos" has high bits set */
 287         pos = *ppos;
 288         if (pos >= len)
 289                 return 0;
 290         if (count > len - pos)
 291                 count = len - pos;
 292         if (!count)
 293                 return 0;
 294
 295         /*
 296          * Magical special case: if the argv[] end byte is not
 297          * zero, the user has overwritten it with setproctitle(3).
 298          *
 299          * Possible future enhancement: do this only once when
 300          * pos is 0, and set a flag in the 'struct file'.
 301          */
 302         if (access_remote_vm(mm, arg_end-1, &c, 1, FOLL_ANON) == 1 && c)
 303                 return get_mm_proctitle(mm, buf, count, pos, arg_start);
 304
 305         /*
 306          * For the non-setproctitle() case we limit things strictly
 307          * to the [arg_start, arg_end[ range.
 308          */
 309         pos += arg_start;
 310         if (pos < arg_start || pos >= arg_end)
 311                 return 0;
 312         if (count > arg_end - pos)
 313                 count = arg_end - pos;
 314
 315         page = (char *)__get_free_page(GFP_KERNEL);
 316         if (!page)
 317                 return -ENOMEM;
 318
 319         len = 0;
 320         while (count) {
 321                 int got;
 322                 size_t size = min_t(size_t, PAGE_SIZE, count);
 323
 324                 got = access_remote_vm(mm, pos, page, size, FOLL_ANON);
 325                 if (got <= 0)
 326                         break;
 327                 got -= copy_to_user(buf, page, got);
 328                 if (unlikely(!got)) {
 329                         if (!len)
 330                                 len = -EFAULT;
 331                         break;
 332                 }
 333                 pos += got;
 334                 buf += got;
 335                 len += got;
 336                 count -= got;
 337         }
 338
 339         free_page((unsigned long)page);
 340         return len;
 341 }
 342
 343 static ssize_t get_task_cmdline(struct task_struct *tsk, char __user *buf,
 344                                 size_t count, loff_t *pos)
 345 {
 346         struct mm_struct *mm;
 347         ssize_t ret;
 348
 349         mm = get_task_mm(tsk);
 350         if (!mm)
 351                 return 0;
 352
 353         ret = get_mm_cmdline(mm, buf, count, pos);
 354         mmput(mm);
 355         return ret;
 356 }
 357
 358 static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
 359                                      size_t count, loff_t *pos)
 360 {
 361         struct task_struct *tsk;
 362         ssize_t ret;
 363
 364         BUG_ON(*pos < 0);
 365
 366         tsk = get_proc_task(file_inode(file));
 367         if (!tsk)
 368                 return -ESRCH;
 369         ret = get_task_cmdline(tsk, buf, count, pos);
 370         put_task_struct(tsk);
 371         if (ret > 0)
 372                 *pos += ret;
 373         return ret;
 374 }
 375
 376 static const struct file_operations proc_pid_cmdline_ops = {
 377         .read   = proc_pid_cmdline_read,
 378         .llseek = generic_file_llseek,
 379 };
 380
 381 #ifdef CONFIG_KALLSYMS
 382 /*
 383  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 384  * Returns the resolved symbol.  If that fails, simply return the address.
 385  */
 386 static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 387                           struct pid *pid, struct task_struct *task)
 388 {
 389         unsigned long wchan;
 390         char symname[KSYM_NAME_LEN];
 391
 392         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
 393                 goto print0;
 394
 395         wchan = get_wchan(task);
 396         if (wchan && !lookup_symbol_name(wchan, symname)) {
 397                 seq_puts(m, symname);
 398                 return 0;
 399         }
 400
 401 print0:
 402         seq_putc(m, '0');
 403         return 0;
 404 }
 405 #endif /* CONFIG_KALLSYMS */
 406
 407 static int lock_trace(struct task_struct *task)
 408 {
 409         int err = down_read_killable(&task->signal->exec_update_lock);
 410         if (err)
 411                 return err;
 412         if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
 413                 up_read(&task->signal->exec_update_lock);
 414                 return -EPERM;
 415         }
 416         return 0;
 417 }
 418
 419 static void unlock_trace(struct task_struct *task)
 420 {
 421         up_read(&task->signal->exec_update_lock);
 422 }
 423
 424 #ifdef CONFIG_STACKTRACE
 425
 426 #define MAX_STACK_TRACE_DEPTH   64
 427
 428 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 429                           struct pid *pid, struct task_struct *task)
 430 {
 431         unsigned long *entries;
 432         int err;
 433
 434         /*
 435          * The ability to racily run the kernel stack unwinder on a running task
 436          * and then observe the unwinder output is scary; while it is useful for
 437          * debugging kernel issues, it can also allow an attacker to leak kernel
 438          * stack contents.
 439          * Doing this in a manner that is at least safe from races would require
 440          * some work to ensure that the remote task can not be scheduled; and
 441          * even then, this would still expose the unwinder as local attack
 442          * surface.
 443          * Therefore, this interface is restricted to root.
 444          */
 445         if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
 446                 return -EACCES;
 447
 448         entries = kmalloc_array(MAX_STACK_TRACE_DEPTH, sizeof(*entries),
 449                                 GFP_KERNEL);
 450         if (!entries)
 451                 return -ENOMEM;
 452
 453         err = lock_trace(task);
 454         if (!err) {
 455                 unsigned int i, nr_entries;
 456
 457                 nr_entries = stack_trace_save_tsk(task, entries,
 458                                                   MAX_STACK_TRACE_DEPTH, 0);
 459
 460                 for (i = 0; i < nr_entries; i++) {
 461                         seq_printf(m, "[<0>] %pB\n", (void *)entries[i]);
 462                 }
 463
 464                 unlock_trace(task);
 465         }
 466         kfree(entries);
 467
 468         return err;
 469 }
 470 #endif
 471
 472 #ifdef CONFIG_SCHED_INFO
 473 /*
 474  * Provides /proc/PID/schedstat
 475  */
 476 static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 477                               struct pid *pid, struct task_struct *task)
 478 {
 479         if (unlikely(!sched_info_on()))
 480                 seq_puts(m, "0 0 0\n");
 481         else
 482                 seq_printf(m, "%llu %llu %lu\n",
 483                    (unsigned long long)task->se.sum_exec_runtime,
 484                    (unsigned long long)task->sched_info.run_delay,
 485                    task->sched_info.pcount);
 486
 487         return 0;
 488 }
 489 #endif
 490
 491 #ifdef CONFIG_LATENCYTOP
 492 static int lstats_show_proc(struct seq_file *m, void *v)
 493 {
 494         int i;
 495         struct inode *inode = m->private;
 496         struct task_struct *task = get_proc_task(inode);
 497
 498         if (!task)
 499                 return -ESRCH;
 500         seq_puts(m, "Latency Top version : v0.1\n");
 501         for (i = 0; i < LT_SAVECOUNT; i++) {
 502                 struct latency_record *lr = &task->latency_record[i];
 503                 if (lr->backtrace[0]) {
 504                         int q;
 505                         seq_printf(m, "%i %li %li",
 506                                    lr->count, lr->time, lr->max);
 507                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 508                                 unsigned long bt = lr->backtrace[q];
 509
 510                                 if (!bt)
 511                                         break;
 512                                 seq_printf(m, " %ps", (void *)bt);
 513                         }
 514                         seq_putc(m, '\n');
 515                 }
 516
 517         }
 518         put_task_struct(task);
 519         return 0;
 520 }
 521
 522 static int lstats_open(struct inode *inode, struct file *file)
 523 {
 524         return single_open(file, lstats_show_proc, inode);
 525 }
 526
 527 static ssize_t lstats_write(struct file *file, const char __user *buf,
 528                             size_t count, loff_t *offs)
 529 {
 530         struct task_struct *task = get_proc_task(file_inode(file));
 531
 532         if (!task)
 533                 return -ESRCH;
 534         clear_tsk_latency_tracing(task);
 535         put_task_struct(task);
 536
 537         return count;
 538 }
 539
 540 static const struct file_operations proc_lstats_operations = {
 541         .open           = lstats_open,
 542         .read           = seq_read,
 543         .write          = lstats_write,
 544         .llseek         = seq_lseek,
 545         .release        = single_release,
 546 };
 547
 548 #endif
 549
 550 static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
 551                           struct pid *pid, struct task_struct *task)
 552 {
 553         unsigned long totalpages = totalram_pages() + total_swap_pages;
 554         unsigned long points = 0;
 555         long badness;
 556
 557         badness = oom_badness(task, totalpages);
 558         /*
 559          * Special case OOM_SCORE_ADJ_MIN for all others scale the
 560          * badness value into [0, 2000] range which we have been
 561          * exporting for a long time so userspace might depend on it.
 562          */
 563         if (badness != LONG_MIN)
 564                 points = (1000 + badness * 1000 / (long)totalpages) * 2 / 3;
 565
 566         seq_printf(m, "%lu\n", points);
 567
 568         return 0;
 569 }
 570
 571 struct limit_names {
 572         const char *name;
 573         const char *unit;
 574 };
 575
 576 static const struct limit_names lnames[RLIM_NLIMITS] = {
 577         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 578         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 579         [RLIMIT_DATA] = {"Max data size", "bytes"},
 580         [RLIMIT_STACK] = {"Max stack size", "bytes"},
 581         [RLIMIT_CORE] = {"Max core file size", "bytes"},
 582         [RLIMIT_RSS] = {"Max resident set", "bytes"},
 583         [RLIMIT_NPROC] = {"Max processes", "processes"},
 584         [RLIMIT_NOFILE] = {"Max open files", "files"},
 585         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 586         [RLIMIT_AS] = {"Max address space", "bytes"},
 587         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 588         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 589         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 590         [RLIMIT_NICE] = {"Max nice priority", NULL},
 591         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 592         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 593 };
 594
 595 /* Display limits for a process */
 596 static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 597                            struct pid *pid, struct task_struct *task)
 598 {
 599         unsigned int i;
 600         unsigned long flags;
 601
 602         struct rlimit rlim[RLIM_NLIMITS];
 603
 604         if (!lock_task_sighand(task, &flags))
 605                 return 0;
 606         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 607         unlock_task_sighand(task, &flags);
 608
 609         /*
 610          * print the file header
 611          */
 612         seq_puts(m, "Limit                     "
 613                 "Soft Limit           "
 614                 "Hard Limit           "
 615                 "Units     \n");
 616
 617         for (i = 0; i < RLIM_NLIMITS; i++) {
 618                 if (rlim[i].rlim_cur == RLIM_INFINITY)
 619                         seq_printf(m, "%-25s %-20s ",
 620                                    lnames[i].name, "unlimited");
 621                 else
 622                         seq_printf(m, "%-25s %-20lu ",
 623                                    lnames[i].name, rlim[i].rlim_cur);
 624
 625                 if (rlim[i].rlim_max == RLIM_INFINITY)
 626                         seq_printf(m, "%-20s ", "unlimited");
 627                 else
 628                         seq_printf(m, "%-20lu ", rlim[i].rlim_max);
 629
 630                 if (lnames[i].unit)
 631                         seq_printf(m, "%-10s\n", lnames[i].unit);
 632                 else
 633                         seq_putc(m, '\n');
 634         }
 635
 636         return 0;
 637 }
 638
 639 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 640 static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 641                             struct pid *pid, struct task_struct *task)
 642 {
 643         struct syscall_info info;
 644         u64 *args = &info.data.args[0];
 645         int res;
 646
 647         res = lock_trace(task);
 648         if (res)
 649                 return res;
 650
 651         if (task_current_syscall(task, &info))
 652                 seq_puts(m, "running\n");
 653         else if (info.data.nr < 0)
 654                 seq_printf(m, "%d 0x%llx 0x%llx\n",
 655                            info.data.nr, info.sp, info.data.instruction_pointer);
 656         else
 657                 seq_printf(m,
 658                        "%d 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx\n",
 659                        info.data.nr,
 660                        args[0], args[1], args[2], args[3], args[4], args[5],
 661                        info.sp, info.data.instruction_pointer);
 662         unlock_trace(task);
 663
 664         return 0;
 665 }
 666 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 667
 668 /************************************************************************/
 669 /*                       Here the fs part begins                        */
 670 /************************************************************************/
 671
 672 /* permission checks */
 673 static int proc_fd_access_allowed(struct inode *inode)
 674 {
 675         struct task_struct *task;
 676         int allowed = 0;
 677         /* Allow access to a task's file descriptors if it is us or we
 678          * may use ptrace attach to the process and find out that
 679          * information.
 680          */
 681         task = get_proc_task(inode);
 682         if (task) {
 683                 allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 684                 put_task_struct(task);
 685         }
 686         return allowed;
 687 }
 688
 689 int proc_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 690                  struct iattr *attr)
 691 {
 692         int error;
 693         struct inode *inode = d_inode(dentry);
 694
 695         if (attr->ia_valid & ATTR_MODE)
 696                 return -EPERM;
 697
 698         error = setattr_prepare(&init_user_ns, dentry, attr);
 699         if (error)
 700                 return error;
 701
 702         setattr_copy(&init_user_ns, inode, attr);
 703         mark_inode_dirty(inode);
 704         return 0;
 705 }
 706
 707 /*
 708  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 709  * or euid/egid (for hide_pid_min=2)?
 710  */
 711 static bool has_pid_permissions(struct proc_fs_info *fs_info,
 712                                  struct task_struct *task,
 713                                  enum proc_hidepid hide_pid_min)
 714 {
 715         /*
 716          * If 'hidpid' mount option is set force a ptrace check,
 717          * we indicate that we are using a filesystem syscall
 718          * by passing PTRACE_MODE_READ_FSCREDS
 719          */
 720         if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE)
 721                 return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 722
 723         if (fs_info->hide_pid < hide_pid_min)
 724                 return true;
 725         if (in_group_p(fs_info->pid_gid))
 726                 return true;
 727         return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 728 }
 729
 730
 731 static int proc_pid_permission(struct user_namespace *mnt_userns,
 732                                struct inode *inode, int mask)
 733 {
 734         struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
 735         struct task_struct *task;
 736         bool has_perms;
 737
 738         task = get_proc_task(inode);
 739         if (!task)
 740                 return -ESRCH;
 741         has_perms = has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS);
 742         put_task_struct(task);
 743
 744         if (!has_perms) {
 745                 if (fs_info->hide_pid == HIDEPID_INVISIBLE) {
 746                         /*
 747                          * Let's make getdents(), stat(), and open()
 748                          * consistent with each other.  If a process
 749                          * may not stat() a file, it shouldn't be seen
 750                          * in procfs at all.
 751                          */
 752                         return -ENOENT;
 753                 }
 754
 755                 return -EPERM;
 756         }
 757         return generic_permission(&init_user_ns, inode, mask);
 758 }
 759
 760
 761
 762 static const struct inode_operations proc_def_inode_operations = {
 763         .setattr        = proc_setattr,
 764 };
 765
 766 static int proc_single_show(struct seq_file *m, void *v)
 767 {
 768         struct inode *inode = m->private;
 769         struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
 770         struct pid *pid = proc_pid(inode);
 771         struct task_struct *task;
 772         int ret;
 773
 774         task = get_pid_task(pid, PIDTYPE_PID);
 775         if (!task)
 776                 return -ESRCH;
 777
 778         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 779
 780         put_task_struct(task);
 781         return ret;
 782 }
 783
 784 static int proc_single_open(struct inode *inode, struct file *filp)
 785 {
 786         return single_open(filp, proc_single_show, inode);
 787 }
 788
 789 static const struct file_operations proc_single_file_operations = {
 790         .open           = proc_single_open,
 791         .read           = seq_read,
 792         .llseek         = seq_lseek,
 793         .release        = single_release,
 794 };
 795
 796
 797 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
 798 {
 799         struct task_struct *task = get_proc_task(inode);
 800         struct mm_struct *mm = ERR_PTR(-ESRCH);
 801
 802         if (task) {
 803                 mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
 804                 put_task_struct(task);
 805
 806                 if (!IS_ERR_OR_NULL(mm)) {
 807                         /* ensure this mm_struct can't be freed */
 808                         mmgrab(mm);
 809                         /* but do not pin its memory */
 810                         mmput(mm);
 811                 }
 812         }
 813
 814         return mm;
 815 }
 816
 817 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 818 {
 819         struct mm_struct *mm = proc_mem_open(inode, mode);
 820
 821         if (IS_ERR(mm))
 822                 return PTR_ERR(mm);
 823
 824         file->private_data = mm;
 825         return 0;
 826 }
 827
 828 static int mem_open(struct inode *inode, struct file *file)
 829 {
 830         int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
 831
 832         /* OK to pass negative loff_t, we can catch out-of-range */
 833         file->f_mode |= FMODE_UNSIGNED_OFFSET;
 834
 835         return ret;
 836 }
 837
 838 static ssize_t mem_rw(struct file *file, char __user *buf,
 839                         size_t count, loff_t *ppos, int write)
 840 {
 841         struct mm_struct *mm = file->private_data;
 842         unsigned long addr = *ppos;
 843         ssize_t copied;
 844         char *page;
 845         unsigned int flags;
 846
 847         if (!mm)
 848                 return 0;
 849
 850         page = (char *)__get_free_page(GFP_KERNEL);
 851         if (!page)
 852                 return -ENOMEM;
 853
 854         copied = 0;
 855         if (!mmget_not_zero(mm))
 856                 goto free;
 857
 858         flags = FOLL_FORCE | (write ? FOLL_WRITE : 0);
 859
 860         while (count > 0) {
 861                 size_t this_len = min_t(size_t, count, PAGE_SIZE);
 862
 863                 if (write && copy_from_user(page, buf, this_len)) {
 864                         copied = -EFAULT;
 865                         break;
 866                 }
 867
 868                 this_len = access_remote_vm(mm, addr, page, this_len, flags);
 869                 if (!this_len) {
 870                         if (!copied)
 871                                 copied = -EIO;
 872                         break;
 873                 }
 874
 875                 if (!write && copy_to_user(buf, page, this_len)) {
 876                         copied = -EFAULT;
 877                         break;
 878                 }
 879
 880                 buf += this_len;
 881                 addr += this_len;
 882                 copied += this_len;
 883                 count -= this_len;
 884         }
 885         *ppos = addr;
 886
 887         mmput(mm);
 888 free:
 889         free_page((unsigned long) page);
 890         return copied;
 891 }
 892
 893 static ssize_t mem_read(struct file *file, char __user *buf,
 894                         size_t count, loff_t *ppos)
 895 {
 896         return mem_rw(file, buf, count, ppos, 0);
 897 }
 898
 899 static ssize_t mem_write(struct file *file, const char __user *buf,
 900                          size_t count, loff_t *ppos)
 901 {
 902         return mem_rw(file, (char __user*)buf, count, ppos, 1);
 903 }
 904
 905 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 906 {
 907         switch (orig) {
 908         case 0:
 909                 file->f_pos = offset;
 910                 break;
 911         case 1:
 912                 file->f_pos += offset;
 913                 break;
 914         default:
 915                 return -EINVAL;
 916         }
 917         force_successful_syscall_return();
 918         return file->f_pos;
 919 }
 920
 921 static int mem_release(struct inode *inode, struct file *file)
 922 {
 923         struct mm_struct *mm = file->private_data;
 924         if (mm)
 925                 mmdrop(mm);
 926         return 0;
 927 }
 928
 929 static const struct file_operations proc_mem_operations = {
 930         .llseek         = mem_lseek,
 931         .read           = mem_read,
 932         .write          = mem_write,
 933         .open           = mem_open,
 934         .release        = mem_release,
 935 };
 936
 937 static int environ_open(struct inode *inode, struct file *file)
 938 {
 939         return __mem_open(inode, file, PTRACE_MODE_READ);
 940 }
 941
 942 static ssize_t environ_read(struct file *file, char __user *buf,
 943                         size_t count, loff_t *ppos)
 944 {
 945         char *page;
 946         unsigned long src = *ppos;
 947         int ret = 0;
 948         struct mm_struct *mm = file->private_data;
 949         unsigned long env_start, env_end;
 950
 951         /* Ensure the process spawned far enough to have an environment. */
 952         if (!mm || !mm->env_end)
 953                 return 0;
 954
 955         page = (char *)__get_free_page(GFP_KERNEL);
 956         if (!page)
 957                 return -ENOMEM;
 958
 959         ret = 0;
 960         if (!mmget_not_zero(mm))
 961                 goto free;
 962
 963         spin_lock(&mm->arg_lock);
 964         env_start = mm->env_start;
 965         env_end = mm->env_end;
 966         spin_unlock(&mm->arg_lock);
 967
 968         while (count > 0) {
 969                 size_t this_len, max_len;
 970                 int retval;
 971
 972                 if (src >= (env_end - env_start))
 973                         break;
 974
 975                 this_len = env_end - (env_start + src);
 976
 977                 max_len = min_t(size_t, PAGE_SIZE, count);
 978                 this_len = min(max_len, this_len);
 979
 980                 retval = access_remote_vm(mm, (env_start + src), page, this_len, FOLL_ANON);
 981
 982                 if (retval <= 0) {
 983                         ret = retval;
 984                         break;
 985                 }
 986
 987                 if (copy_to_user(buf, page, retval)) {
 988                         ret = -EFAULT;
 989                         break;
 990                 }
 991
 992                 ret += retval;
 993                 src += retval;
 994                 buf += retval;
 995                 count -= retval;
 996         }
 997         *ppos = src;
 998         mmput(mm);
 999
1000 free:
1001         free_page((unsigned long) page);
1002         return ret;
1003 }
1004
1005 static const struct file_operations proc_environ_operations = {
1006         .open           = environ_open,
1007         .read           = environ_read,
1008         .llseek         = generic_file_llseek,
1009         .release        = mem_release,
1010 };
1011
1012 static int auxv_open(struct inode *inode, struct file *file)
1013 {
1014         return __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
1015 }
1016
1017 static ssize_t auxv_read(struct file *file, char __user *buf,
1018                         size_t count, loff_t *ppos)
1019 {
1020         struct mm_struct *mm = file->private_data;
1021         unsigned int nwords = 0;
1022
1023         if (!mm)
1024                 return 0;
1025         do {
1026                 nwords += 2;
1027         } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
1028         return simple_read_from_buffer(buf, count, ppos, mm->saved_auxv,
1029                                        nwords * sizeof(mm->saved_auxv[0]));
1030 }
1031
1032 static const struct file_operations proc_auxv_operations = {
1033         .open           = auxv_open,
1034         .read           = auxv_read,
1035         .llseek         = generic_file_llseek,
1036         .release        = mem_release,
1037 };
1038
1039 static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1040                             loff_t *ppos)
1041 {
1042         struct task_struct *task = get_proc_task(file_inode(file));
1043         char buffer[PROC_NUMBUF];
1044         int oom_adj = OOM_ADJUST_MIN;
1045         size_t len;
1046
1047         if (!task)
1048                 return -ESRCH;
1049         if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1050                 oom_adj = OOM_ADJUST_MAX;
1051         else
1052                 oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1053                           OOM_SCORE_ADJ_MAX;
1054         put_task_struct(task);
1055         if (oom_adj > OOM_ADJUST_MAX)
1056                 oom_adj = OOM_ADJUST_MAX;
1057         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1058         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1059 }
1060
1061 static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1062 {
1063         struct mm_struct *mm = NULL;
1064         struct task_struct *task;
1065         int err = 0;
1066
1067         task = get_proc_task(file_inode(file));
1068         if (!task)
1069                 return -ESRCH;
1070
1071         mutex_lock(&oom_adj_mutex);
1072         if (legacy) {
1073                 if (oom_adj < task->signal->oom_score_adj &&
1074                                 !capable(CAP_SYS_RESOURCE)) {
1075                         err = -EACCES;
1076                         goto err_unlock;
1077                 }
1078                 /*
1079                  * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1080                  * /proc/pid/oom_score_adj instead.
1081                  */
1082                 pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1083                           current->comm, task_pid_nr(current), task_pid_nr(task),
1084                           task_pid_nr(task));
1085         } else {
1086                 if ((short)oom_adj < task->signal->oom_score_adj_min &&
1087                                 !capable(CAP_SYS_RESOURCE)) {
1088                         err = -EACCES;
1089                         goto err_unlock;
1090                 }
1091         }
1092
1093         /*
1094          * Make sure we will check other processes sharing the mm if this is
1095          * not vfrok which wants its own oom_score_adj.
1096          * pin the mm so it doesn't go away and get reused after task_unlock
1097          */
1098         if (!task->vfork_done) {
1099                 struct task_struct *p = find_lock_task_mm(task);
1100
1101                 if (p) {
1102                         if (test_bit(MMF_MULTIPROCESS, &p->mm->flags)) {
1103                                 mm = p->mm;
1104                                 mmgrab(mm);
1105                         }
1106                         task_unlock(p);
1107                 }
1108         }
1109
1110         task->signal->oom_score_adj = oom_adj;
1111         if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1112                 task->signal->oom_score_adj_min = (short)oom_adj;
1113         trace_oom_score_adj_update(task);
1114
1115         if (mm) {
1116                 struct task_struct *p;
1117
1118                 rcu_read_lock();
1119                 for_each_process(p) {
1120                         if (same_thread_group(task, p))
1121                                 continue;
1122
1123                         /* do not touch kernel threads or the global init */
1124                         if (p->flags & PF_KTHREAD || is_global_init(p))
1125                                 continue;
1126
1127                         task_lock(p);
1128                         if (!p->vfork_done && process_shares_mm(p, mm)) {
1129                                 p->signal->oom_score_adj = oom_adj;
1130                                 if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1131                                         p->signal->oom_score_adj_min = (short)oom_adj;
1132                         }
1133                         task_unlock(p);
1134                 }
1135                 rcu_read_unlock();
1136                 mmdrop(mm);
1137         }
1138 err_unlock:
1139         mutex_unlock(&oom_adj_mutex);
1140         put_task_struct(task);
1141         return err;
1142 }
1143
1144 /*
1145  * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1146  * kernels.  The effective policy is defined by oom_score_adj, which has a
1147  * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1148  * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1149  * Processes that become oom disabled via oom_adj will still be oom disabled
1150  * with this implementation.
1151  *
1152  * oom_adj cannot be removed since existing userspace binaries use it.
1153  */
1154 static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1155                              size_t count, loff_t *ppos)
1156 {
1157         char buffer[PROC_NUMBUF];
1158         int oom_adj;
1159         int err;
1160
1161         memset(buffer, 0, sizeof(buffer));
1162         if (count > sizeof(buffer) - 1)
1163                 count = sizeof(buffer) - 1;
1164         if (copy_from_user(buffer, buf, count)) {
1165                 err = -EFAULT;
1166                 goto out;
1167         }
1168
1169         err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1170         if (err)
1171                 goto out;
1172         if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1173              oom_adj != OOM_DISABLE) {
1174                 err = -EINVAL;
1175                 goto out;
1176         }
1177
1178         /*
1179          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1180          * value is always attainable.
1181          */
1182         if (oom_adj == OOM_ADJUST_MAX)
1183                 oom_adj = OOM_SCORE_ADJ_MAX;
1184         else
1185                 oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1186
1187         err = __set_oom_adj(file, oom_adj, true);
1188 out:
1189         return err < 0 ? err : count;
1190 }
1191
1192 static const struct file_operations proc_oom_adj_operations = {
1193         .read           = oom_adj_read,
1194         .write          = oom_adj_write,
1195         .llseek         = generic_file_llseek,
1196 };
1197
1198 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1199                                         size_t count, loff_t *ppos)
1200 {
1201         struct task_struct *task = get_proc_task(file_inode(file));
1202         char buffer[PROC_NUMBUF];
1203         short oom_score_adj = OOM_SCORE_ADJ_MIN;
1204         size_t len;
1205
1206         if (!task)
1207                 return -ESRCH;
1208         oom_score_adj = task->signal->oom_score_adj;
1209         put_task_struct(task);
1210         len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1211         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1212 }
1213
1214 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1215                                         size_t count, loff_t *ppos)
1216 {
1217         char buffer[PROC_NUMBUF];
1218         int oom_score_adj;
1219         int err;
1220
1221         memset(buffer, 0, sizeof(buffer));
1222         if (count > sizeof(buffer) - 1)
1223                 count = sizeof(buffer) - 1;
1224         if (copy_from_user(buffer, buf, count)) {
1225                 err = -EFAULT;
1226                 goto out;
1227         }
1228
1229         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1230         if (err)
1231                 goto out;
1232         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1233                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1234                 err = -EINVAL;
1235                 goto out;
1236         }
1237
1238         err = __set_oom_adj(file, oom_score_adj, false);
1239 out:
1240         return err < 0 ? err : count;
1241 }
1242
1243 static const struct file_operations proc_oom_score_adj_operations = {
1244         .read           = oom_score_adj_read,
1245         .write          = oom_score_adj_write,
1246         .llseek         = default_llseek,
1247 };
1248
1249 #ifdef CONFIG_AUDIT
1250 #define TMPBUFLEN 11
1251 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1252                                   size_t count, loff_t *ppos)
1253 {
1254         struct inode * inode = file_inode(file);
1255         struct task_struct *task = get_proc_task(inode);
1256         ssize_t length;
1257         char tmpbuf[TMPBUFLEN];
1258
1259         if (!task)
1260                 return -ESRCH;
1261         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1262                            from_kuid(file->f_cred->user_ns,
1263                                      audit_get_loginuid(task)));
1264         put_task_struct(task);
1265         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1266 }
1267
1268 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1269                                    size_t count, loff_t *ppos)
1270 {
1271         struct inode * inode = file_inode(file);
1272         uid_t loginuid;
1273         kuid_t kloginuid;
1274         int rv;
1275
1276         /* Don't let kthreads write their own loginuid */
1277         if (current->flags & PF_KTHREAD)
1278                 return -EPERM;
1279
1280         rcu_read_lock();
1281         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1282                 rcu_read_unlock();
1283                 return -EPERM;
1284         }
1285         rcu_read_unlock();
1286
1287         if (*ppos != 0) {
1288                 /* No partial writes. */
1289                 return -EINVAL;
1290         }
1291
1292         rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1293         if (rv < 0)
1294                 return rv;
1295
1296         /* is userspace tring to explicitly UNSET the loginuid? */
1297         if (loginuid == AUDIT_UID_UNSET) {
1298                 kloginuid = INVALID_UID;
1299         } else {
1300                 kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1301                 if (!uid_valid(kloginuid))
1302                         return -EINVAL;
1303         }
1304
1305         rv = audit_set_loginuid(kloginuid);
1306         if (rv < 0)
1307                 return rv;
1308         return count;
1309 }
1310
1311 static const struct file_operations proc_loginuid_operations = {
1312         .read           = proc_loginuid_read,
1313         .write          = proc_loginuid_write,
1314         .llseek         = generic_file_llseek,
1315 };
1316
1317 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1318                                   size_t count, loff_t *ppos)
1319 {
1320         struct inode * inode = file_inode(file);
1321         struct task_struct *task = get_proc_task(inode);
1322         ssize_t length;
1323         char tmpbuf[TMPBUFLEN];
1324
1325         if (!task)
1326                 return -ESRCH;
1327         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1328                                 audit_get_sessionid(task));
1329         put_task_struct(task);
1330         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1331 }
1332
1333 static const struct file_operations proc_sessionid_operations = {
1334         .read           = proc_sessionid_read,
1335         .llseek         = generic_file_llseek,
1336 };
1337 #endif
1338
1339 #ifdef CONFIG_FAULT_INJECTION
1340 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1341                                       size_t count, loff_t *ppos)
1342 {
1343         struct task_struct *task = get_proc_task(file_inode(file));
1344         char buffer[PROC_NUMBUF];
1345         size_t len;
1346         int make_it_fail;
1347
1348         if (!task)
1349                 return -ESRCH;
1350         make_it_fail = task->make_it_fail;
1351         put_task_struct(task);
1352
1353         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1354
1355         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1356 }
1357
1358 static ssize_t proc_fault_inject_write(struct file * file,
1359                         const char __user * buf, size_t count, loff_t *ppos)
1360 {
1361         struct task_struct *task;
1362         char buffer[PROC_NUMBUF];
1363         int make_it_fail;
1364         int rv;
1365
1366         if (!capable(CAP_SYS_RESOURCE))
1367                 return -EPERM;
1368         memset(buffer, 0, sizeof(buffer));
1369         if (count > sizeof(buffer) - 1)
1370                 count = sizeof(buffer) - 1;
1371         if (copy_from_user(buffer, buf, count))
1372                 return -EFAULT;
1373         rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1374         if (rv < 0)
1375                 return rv;
1376         if (make_it_fail < 0 || make_it_fail > 1)
1377                 return -EINVAL;
1378
1379         task = get_proc_task(file_inode(file));
1380         if (!task)
1381                 return -ESRCH;
1382         task->make_it_fail = make_it_fail;
1383         put_task_struct(task);
1384
1385         return count;
1386 }
1387
1388 static const struct file_operations proc_fault_inject_operations = {
1389         .read           = proc_fault_inject_read,
1390         .write          = proc_fault_inject_write,
1391         .llseek         = generic_file_llseek,
1392 };
1393
1394 static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
1395                                    size_t count, loff_t *ppos)
1396 {
1397         struct task_struct *task;
1398         int err;
1399         unsigned int n;
1400
1401         err = kstrtouint_from_user(buf, count, 0, &n);
1402         if (err)
1403                 return err;
1404
1405         task = get_proc_task(file_inode(file));
1406         if (!task)
1407                 return -ESRCH;
1408         task->fail_nth = n;
1409         put_task_struct(task);
1410
1411         return count;
1412 }
1413
1414 static ssize_t proc_fail_nth_read(struct file *file, char __user *buf,
1415                                   size_t count, loff_t *ppos)
1416 {
1417         struct task_struct *task;
1418         char numbuf[PROC_NUMBUF];
1419         ssize_t len;
1420
1421         task = get_proc_task(file_inode(file));
1422         if (!task)
1423                 return -ESRCH;
1424         len = snprintf(numbuf, sizeof(numbuf), "%u\n", task->fail_nth);
1425         put_task_struct(task);
1426         return simple_read_from_buffer(buf, count, ppos, numbuf, len);
1427 }
1428
1429 static const struct file_operations proc_fail_nth_operations = {
1430         .read           = proc_fail_nth_read,
1431         .write          = proc_fail_nth_write,
1432 };
1433 #endif
1434
1435
1436 #ifdef CONFIG_SCHED_DEBUG
1437 /*
1438  * Print out various scheduling related per-task fields:
1439  */
1440 static int sched_show(struct seq_file *m, void *v)
1441 {
1442         struct inode *inode = m->private;
1443         struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
1444         struct task_struct *p;
1445
1446         p = get_proc_task(inode);
1447         if (!p)
1448                 return -ESRCH;
1449         proc_sched_show_task(p, ns, m);
1450
1451         put_task_struct(p);
1452
1453         return 0;
1454 }
1455
1456 static ssize_t
1457 sched_write(struct file *file, const char __user *buf,
1458             size_t count, loff_t *offset)
1459 {
1460         struct inode *inode = file_inode(file);
1461         struct task_struct *p;
1462
1463         p = get_proc_task(inode);
1464         if (!p)
1465                 return -ESRCH;
1466         proc_sched_set_task(p);
1467
1468         put_task_struct(p);
1469
1470         return count;
1471 }
1472
1473 static int sched_open(struct inode *inode, struct file *filp)
1474 {
1475         return single_open(filp, sched_show, inode);
1476 }
1477
1478 static const struct file_operations proc_pid_sched_operations = {
1479         .open           = sched_open,
1480         .read           = seq_read,
1481         .write          = sched_write,
1482         .llseek         = seq_lseek,
1483         .release        = single_release,
1484 };
1485
1486 #endif
1487
1488 #ifdef CONFIG_SCHED_AUTOGROUP
1489 /*
1490  * Print out autogroup related information:
1491  */
1492 static int sched_autogroup_show(struct seq_file *m, void *v)
1493 {
1494         struct inode *inode = m->private;
1495         struct task_struct *p;
1496
1497         p = get_proc_task(inode);
1498         if (!p)
1499                 return -ESRCH;
1500         proc_sched_autogroup_show_task(p, m);
1501
1502         put_task_struct(p);
1503
1504         return 0;
1505 }
1506
1507 static ssize_t
1508 sched_autogroup_write(struct file *file, const char __user *buf,
1509             size_t count, loff_t *offset)
1510 {
1511         struct inode *inode = file_inode(file);
1512         struct task_struct *p;
1513         char buffer[PROC_NUMBUF];
1514         int nice;
1515         int err;
1516
1517         memset(buffer, 0, sizeof(buffer));
1518         if (count > sizeof(buffer) - 1)
1519                 count = sizeof(buffer) - 1;
1520         if (copy_from_user(buffer, buf, count))
1521                 return -EFAULT;
1522
1523         err = kstrtoint(strstrip(buffer), 0, &nice);
1524         if (err < 0)
1525                 return err;
1526
1527         p = get_proc_task(inode);
1528         if (!p)
1529                 return -ESRCH;
1530
1531         err = proc_sched_autogroup_set_nice(p, nice);
1532         if (err)
1533                 count = err;
1534
1535         put_task_struct(p);
1536
1537         return count;
1538 }
1539
1540 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1541 {
1542         int ret;
1543
1544         ret = single_open(filp, sched_autogroup_show, NULL);
1545         if (!ret) {
1546                 struct seq_file *m = filp->private_data;
1547
1548                 m->private = inode;
1549         }
1550         return ret;
1551 }
1552
1553 static const struct file_operations proc_pid_sched_autogroup_operations = {
1554         .open           = sched_autogroup_open,
1555         .read           = seq_read,
1556         .write          = sched_autogroup_write,
1557         .llseek         = seq_lseek,
1558         .release        = single_release,
1559 };
1560
1561 #endif /* CONFIG_SCHED_AUTOGROUP */
1562
1563 #ifdef CONFIG_TIME_NS
1564 static int timens_offsets_show(struct seq_file *m, void *v)
1565 {
1566         struct task_struct *p;
1567
1568         p = get_proc_task(file_inode(m->file));
1569         if (!p)
1570                 return -ESRCH;
1571         proc_timens_show_offsets(p, m);
1572
1573         put_task_struct(p);
1574
1575         return 0;
1576 }
1577
1578 static ssize_t timens_offsets_write(struct file *file, const char __user *buf,
1579                                     size_t count, loff_t *ppos)
1580 {
1581         struct inode *inode = file_inode(file);
1582         struct proc_timens_offset offsets[2];
1583         char *kbuf = NULL, *pos, *next_line;
1584         struct task_struct *p;
1585         int ret, noffsets;
1586
1587         /* Only allow < page size writes at the beginning of the file */
1588         if ((*ppos != 0) || (count >= PAGE_SIZE))
1589                 return -EINVAL;
1590
1591         /* Slurp in the user data */
1592         kbuf = memdup_user_nul(buf, count);
1593         if (IS_ERR(kbuf))
1594                 return PTR_ERR(kbuf);
1595
1596         /* Parse the user data */
1597         ret = -EINVAL;
1598         noffsets = 0;
1599         for (pos = kbuf; pos; pos = next_line) {
1600                 struct proc_timens_offset *off = &offsets[noffsets];
1601                 char clock[10];
1602                 int err;
1603
1604                 /* Find the end of line and ensure we don't look past it */
1605                 next_line = strchr(pos, '\n');
1606                 if (next_line) {
1607                         *next_line = '\0';
1608                         next_line++;
1609                         if (*next_line == '\0')
1610                                 next_line = NULL;
1611                 }
1612
1613                 err = sscanf(pos, "%9s %lld %lu", clock,
1614                                 &off->val.tv_sec, &off->val.tv_nsec);
1615                 if (err != 3 || off->val.tv_nsec >= NSEC_PER_SEC)
1616                         goto out;
1617
1618                 clock[sizeof(clock) - 1] = 0;
1619                 if (strcmp(clock, "monotonic") == 0 ||
1620                     strcmp(clock, __stringify(CLOCK_MONOTONIC)) == 0)
1621                         off->clockid = CLOCK_MONOTONIC;
1622                 else if (strcmp(clock, "boottime") == 0 ||
1623                          strcmp(clock, __stringify(CLOCK_BOOTTIME)) == 0)
1624                         off->clockid = CLOCK_BOOTTIME;
1625                 else
1626                         goto out;
1627
1628                 noffsets++;
1629                 if (noffsets == ARRAY_SIZE(offsets)) {
1630                         if (next_line)
1631                                 count = next_line - kbuf;
1632                         break;
1633                 }
1634         }
1635
1636         ret = -ESRCH;
1637         p = get_proc_task(inode);
1638         if (!p)
1639                 goto out;
1640         ret = proc_timens_set_offset(file, p, offsets, noffsets);
1641         put_task_struct(p);
1642         if (ret)
1643                 goto out;
1644
1645         ret = count;
1646 out:
1647         kfree(kbuf);
1648         return ret;
1649 }
1650
1651 static int timens_offsets_open(struct inode *inode, struct file *filp)
1652 {
1653         return single_open(filp, timens_offsets_show, inode);
1654 }
1655
1656 static const struct file_operations proc_timens_offsets_operations = {
1657         .open           = timens_offsets_open,
1658         .read           = seq_read,
1659         .write          = timens_offsets_write,
1660         .llseek         = seq_lseek,
1661         .release        = single_release,
1662 };
1663 #endif /* CONFIG_TIME_NS */
1664
1665 static ssize_t comm_write(struct file *file, const char __user *buf,
1666                                 size_t count, loff_t *offset)
1667 {
1668         struct inode *inode = file_inode(file);
1669         struct task_struct *p;
1670         char buffer[TASK_COMM_LEN];
1671         const size_t maxlen = sizeof(buffer) - 1;
1672
1673         memset(buffer, 0, sizeof(buffer));
1674         if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1675                 return -EFAULT;
1676
1677         p = get_proc_task(inode);
1678         if (!p)
1679                 return -ESRCH;
1680
1681         if (same_thread_group(current, p)) {
1682                 set_task_comm(p, buffer);
1683                 proc_comm_connector(p);
1684         }
1685         else
1686                 count = -EINVAL;
1687
1688         put_task_struct(p);
1689
1690         return count;
1691 }
1692
1693 static int comm_show(struct seq_file *m, void *v)
1694 {
1695         struct inode *inode = m->private;
1696         struct task_struct *p;
1697
1698         p = get_proc_task(inode);
1699         if (!p)
1700                 return -ESRCH;
1701
1702         proc_task_name(m, p, false);
1703         seq_putc(m, '\n');
1704
1705         put_task_struct(p);
1706
1707         return 0;
1708 }
1709
1710 static int comm_open(struct inode *inode, struct file *filp)
1711 {
1712         return single_open(filp, comm_show, inode);
1713 }
1714
1715 static const struct file_operations proc_pid_set_comm_operations = {
1716         .open           = comm_open,
1717         .read           = seq_read,
1718         .write          = comm_write,
1719         .llseek         = seq_lseek,
1720         .release        = single_release,
1721 };
1722
1723 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1724 {
1725         struct task_struct *task;
1726         struct file *exe_file;
1727
1728         task = get_proc_task(d_inode(dentry));
1729         if (!task)
1730                 return -ENOENT;
1731         exe_file = get_task_exe_file(task);
1732         put_task_struct(task);
1733         if (exe_file) {
1734                 *exe_path = exe_file->f_path;
1735                 path_get(&exe_file->f_path);
1736                 fput(exe_file);
1737                 return 0;
1738         } else
1739                 return -ENOENT;
1740 }
1741
1742 static const char *proc_pid_get_link(struct dentry *dentry,
1743                                      struct inode *inode,
1744                                      struct delayed_call *done)
1745 {
1746         struct path path;
1747         int error = -EACCES;
1748
1749         if (!dentry)
1750                 return ERR_PTR(-ECHILD);
1751
1752         /* Are we allowed to snoop on the tasks file descriptors? */
1753         if (!proc_fd_access_allowed(inode))
1754                 goto out;
1755
1756         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1757         if (error)
1758                 goto out;
1759
1760         error = nd_jump_link(&path);
1761 out:
1762         return ERR_PTR(error);
1763 }
1764
1765 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1766 {
1767         char *tmp = (char *)__get_free_page(GFP_KERNEL);
1768         char *pathname;
1769         int len;
1770
1771         if (!tmp)
1772                 return -ENOMEM;
1773
1774         pathname = d_path(path, tmp, PAGE_SIZE);
1775         len = PTR_ERR(pathname);
1776         if (IS_ERR(pathname))
1777                 goto out;
1778         len = tmp + PAGE_SIZE - 1 - pathname;
1779
1780         if (len > buflen)
1781                 len = buflen;
1782         if (copy_to_user(buffer, pathname, len))
1783                 len = -EFAULT;
1784  out:
1785         free_page((unsigned long)tmp);
1786         return len;
1787 }
1788
1789 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1790 {
1791         int error = -EACCES;
1792         struct inode *inode = d_inode(dentry);
1793         struct path path;
1794
1795         /* Are we allowed to snoop on the tasks file descriptors? */
1796         if (!proc_fd_access_allowed(inode))
1797                 goto out;
1798
1799         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1800         if (error)
1801                 goto out;
1802
1803         error = do_proc_readlink(&path, buffer, buflen);
1804         path_put(&path);
1805 out:
1806         return error;
1807 }
1808
1809 const struct inode_operations proc_pid_link_inode_operations = {
1810         .readlink       = proc_pid_readlink,
1811         .get_link       = proc_pid_get_link,
1812         .setattr        = proc_setattr,
1813 };
1814
1815
1816 /* building an inode */
1817
1818 void task_dump_owner(struct task_struct *task, umode_t mode,
1819                      kuid_t *ruid, kgid_t *rgid)
1820 {
1821         /* Depending on the state of dumpable compute who should own a
1822          * proc file for a task.
1823          */
1824         const struct cred *cred;
1825         kuid_t uid;
1826         kgid_t gid;
1827
1828         if (unlikely(task->flags & PF_KTHREAD)) {
1829                 *ruid = GLOBAL_ROOT_UID;
1830                 *rgid = GLOBAL_ROOT_GID;
1831                 return;
1832         }
1833
1834         /* Default to the tasks effective ownership */
1835         rcu_read_lock();
1836         cred = __task_cred(task);
1837         uid = cred->euid;
1838         gid = cred->egid;
1839         rcu_read_unlock();
1840
1841         /*
1842          * Before the /proc/pid/status file was created the only way to read
1843          * the effective uid of a /process was to stat /proc/pid.  Reading
1844          * /proc/pid/status is slow enough that procps and other packages
1845          * kept stating /proc/pid.  To keep the rules in /proc simple I have
1846          * made this apply to all per process world readable and executable
1847          * directories.
1848          */
1849         if (mode != (S_IFDIR|S_IRUGO|S_IXUGO)) {
1850                 struct mm_struct *mm;
1851                 task_lock(task);
1852                 mm = task->mm;
1853                 /* Make non-dumpable tasks owned by some root */
1854                 if (mm) {
1855                         if (get_dumpable(mm) != SUID_DUMP_USER) {
1856                                 struct user_namespace *user_ns = mm->user_ns;
1857
1858                                 uid = make_kuid(user_ns, 0);
1859                                 if (!uid_valid(uid))
1860                                         uid = GLOBAL_ROOT_UID;
1861
1862                                 gid = make_kgid(user_ns, 0);
1863                                 if (!gid_valid(gid))
1864                                         gid = GLOBAL_ROOT_GID;
1865                         }
1866                 } else {
1867                         uid = GLOBAL_ROOT_UID;
1868                         gid = GLOBAL_ROOT_GID;
1869                 }
1870                 task_unlock(task);
1871         }
1872         *ruid = uid;
1873         *rgid = gid;
1874 }
1875
1876 void proc_pid_evict_inode(struct proc_inode *ei)
1877 {
1878         struct pid *pid = ei->pid;
1879
1880         if (S_ISDIR(ei->vfs_inode.i_mode)) {
1881                 spin_lock(&pid->lock);
1882                 hlist_del_init_rcu(&ei->sibling_inodes);
1883                 spin_unlock(&pid->lock);
1884         }
1885
1886         put_pid(pid);
1887 }
1888
1889 struct inode *proc_pid_make_inode(struct super_block * sb,
1890                                   struct task_struct *task, umode_t mode)
1891 {
1892         struct inode * inode;
1893         struct proc_inode *ei;
1894         struct pid *pid;
1895
1896         /* We need a new inode */
1897
1898         inode = new_inode(sb);
1899         if (!inode)
1900                 goto out;
1901
1902         /* Common stuff */
1903         ei = PROC_I(inode);
1904         inode->i_mode = mode;
1905         inode->i_ino = get_next_ino();
1906         inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
1907         inode->i_op = &proc_def_inode_operations;
1908
1909         /*
1910          * grab the reference to task.
1911          */
1912         pid = get_task_pid(task, PIDTYPE_PID);
1913         if (!pid)
1914                 goto out_unlock;
1915
1916         /* Let the pid remember us for quick removal */
1917         ei->pid = pid;
1918         if (S_ISDIR(mode)) {
1919                 spin_lock(&pid->lock);
1920                 hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes);
1921                 spin_unlock(&pid->lock);
1922         }
1923
1924         task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1925         security_task_to_inode(task, inode);
1926
1927 out:
1928         return inode;
1929
1930 out_unlock:
1931         iput(inode);
1932         return NULL;
1933 }
1934
1935 int pid_getattr(struct user_namespace *mnt_userns, const struct path *path,
1936                 struct kstat *stat, u32 request_mask, unsigned int query_flags)
1937 {
1938         struct inode *inode = d_inode(path->dentry);
1939         struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
1940         struct task_struct *task;
1941
1942         generic_fillattr(&init_user_ns, inode, stat);
1943
1944         stat->uid = GLOBAL_ROOT_UID;
1945         stat->gid = GLOBAL_ROOT_GID;
1946         rcu_read_lock();
1947         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1948         if (task) {
1949                 if (!has_pid_permissions(fs_info, task, HIDEPID_INVISIBLE)) {
1950                         rcu_read_unlock();
1951                         /*
1952                          * This doesn't prevent learning whether PID exists,
1953                          * it only makes getattr() consistent with readdir().
1954                          */
1955                         return -ENOENT;
1956                 }
1957                 task_dump_owner(task, inode->i_mode, &stat->uid, &stat->gid);
1958         }
1959         rcu_read_unlock();
1960         return 0;
1961 }
1962
1963 /* dentry stuff */
1964
1965 /*
1966  * Set <pid>/... inode ownership (can change due to setuid(), etc.)
1967  */
1968 void pid_update_inode(struct task_struct *task, struct inode *inode)
1969 {
1970         task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid);
1971
1972         inode->i_mode &= ~(S_ISUID | S_ISGID);
1973         security_task_to_inode(task, inode);
1974 }
1975
1976 /*
1977  * Rewrite the inode's ownerships here because the owning task may have
1978  * performed a setuid(), etc.
1979  *
1980  */
1981 static int pid_revalidate(struct dentry *dentry, unsigned int flags)
1982 {
1983         struct inode *inode;
1984         struct task_struct *task;
1985
1986         if (flags & LOOKUP_RCU)
1987                 return -ECHILD;
1988
1989         inode = d_inode(dentry);
1990         task = get_proc_task(inode);
1991
1992         if (task) {
1993                 pid_update_inode(task, inode);
1994                 put_task_struct(task);
1995                 return 1;
1996         }
1997         return 0;
1998 }
1999
2000 static inline bool proc_inode_is_dead(struct inode *inode)
2001 {
2002         return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
2003 }
2004
2005 int pid_delete_dentry(const struct dentry *dentry)
2006 {
2007         /* Is the task we represent dead?
2008          * If so, then don't put the dentry on the lru list,
2009          * kill it immediately.
2010          */
2011         return proc_inode_is_dead(d_inode(dentry));
2012 }
2013
2014 const struct dentry_operations pid_dentry_operations =
2015 {
2016         .d_revalidate   = pid_revalidate,
2017         .d_delete       = pid_delete_dentry,
2018 };
2019
2020 /* Lookups */
2021
2022 /*
2023  * Fill a directory entry.
2024  *
2025  * If possible create the dcache entry and derive our inode number and
2026  * file type from dcache entry.
2027  *
2028  * Since all of the proc inode numbers are dynamically generated, the inode
2029  * numbers do not exist until the inode is cache.  This means creating
2030  * the dcache entry in readdir is necessary to keep the inode numbers
2031  * reported by readdir in sync with the inode numbers reported
2032  * by stat.
2033  */
2034 bool proc_fill_cache(struct file *file, struct dir_context *ctx,
2035         const char *name, unsigned int len,
2036         instantiate_t instantiate, struct task_struct *task, const void *ptr)
2037 {
2038         struct dentry *child, *dir = file->f_path.dentry;
2039         struct qstr qname = QSTR_INIT(name, len);
2040         struct inode *inode;
2041         unsigned type = DT_UNKNOWN;
2042         ino_t ino = 1;
2043
2044         child = d_hash_and_lookup(dir, &qname);
2045         if (!child) {
2046                 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
2047                 child = d_alloc_parallel(dir, &qname, &wq);
2048                 if (IS_ERR(child))
2049                         goto end_instantiate;
2050                 if (d_in_lookup(child)) {
2051                         struct dentry *res;
2052                         res = instantiate(child, task, ptr);
2053                         d_lookup_done(child);
2054                         if (unlikely(res)) {
2055                                 dput(child);
2056                                 child = res;
2057                                 if (IS_ERR(child))
2058                                         goto end_instantiate;
2059                         }
2060                 }
2061         }
2062         inode = d_inode(child);
2063         ino = inode->i_ino;
2064         type = inode->i_mode >> 12;
2065         dput(child);
2066 end_instantiate:
2067         return dir_emit(ctx, name, len, ino, type);
2068 }
2069
2070 /*
2071  * dname_to_vma_addr - maps a dentry name into two unsigned longs
2072  * which represent vma start and end addresses.
2073  */
2074 static int dname_to_vma_addr(struct dentry *dentry,
2075                              unsigned long *start, unsigned long *end)
2076 {
2077         const char *str = dentry->d_name.name;
2078         unsigned long long sval, eval;
2079         unsigned int len;
2080
2081         if (str[0] == '0' && str[1] != '-')
2082                 return -EINVAL;
2083         len = _parse_integer(str, 16, &sval);
2084         if (len & KSTRTOX_OVERFLOW)
2085                 return -EINVAL;
2086         if (sval != (unsigned long)sval)
2087                 return -EINVAL;
2088         str += len;
2089
2090         if (*str != '-')
2091                 return -EINVAL;
2092         str++;
2093
2094         if (str[0] == '0' && str[1])
2095                 return -EINVAL;
2096         len = _parse_integer(str, 16, &eval);
2097         if (len & KSTRTOX_OVERFLOW)
2098                 return -EINVAL;
2099         if (eval != (unsigned long)eval)
2100                 return -EINVAL;
2101         str += len;
2102
2103         if (*str != '\0')
2104                 return -EINVAL;
2105
2106         *start = sval;
2107         *end = eval;
2108
2109         return 0;
2110 }
2111
2112 static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
2113 {
2114         unsigned long vm_start, vm_end;
2115         bool exact_vma_exists = false;
2116         struct mm_struct *mm = NULL;
2117         struct task_struct *task;
2118         struct inode *inode;
2119         int status = 0;
2120
2121         if (flags & LOOKUP_RCU)
2122                 return -ECHILD;
2123
2124         inode = d_inode(dentry);
2125         task = get_proc_task(inode);
2126         if (!task)
2127                 goto out_notask;
2128
2129         mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
2130         if (IS_ERR_OR_NULL(mm))
2131                 goto out;
2132
2133         if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
2134                 status = mmap_read_lock_killable(mm);
2135                 if (!status) {
2136                         exact_vma_exists = !!find_exact_vma(mm, vm_start,
2137                                                             vm_end);
2138                         mmap_read_unlock(mm);
2139                 }
2140         }
2141
2142         mmput(mm);
2143
2144         if (exact_vma_exists) {
2145                 task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
2146
2147                 security_task_to_inode(task, inode);
2148                 status = 1;
2149         }
2150
2151 out:
2152         put_task_struct(task);
2153
2154 out_notask:
2155         return status;
2156 }
2157
2158 static const struct dentry_operations tid_map_files_dentry_operations = {
2159         .d_revalidate   = map_files_d_revalidate,
2160         .d_delete       = pid_delete_dentry,
2161 };
2162
2163 static int map_files_get_link(struct dentry *dentry, struct path *path)
2164 {
2165         unsigned long vm_start, vm_end;
2166         struct vm_area_struct *vma;
2167         struct task_struct *task;
2168         struct mm_struct *mm;
2169         int rc;
2170
2171         rc = -ENOENT;
2172         task = get_proc_task(d_inode(dentry));
2173         if (!task)
2174                 goto out;
2175
2176         mm = get_task_mm(task);
2177         put_task_struct(task);
2178         if (!mm)
2179                 goto out;
2180
2181         rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
2182         if (rc)
2183                 goto out_mmput;
2184
2185         rc = mmap_read_lock_killable(mm);
2186         if (rc)
2187                 goto out_mmput;
2188
2189         rc = -ENOENT;
2190         vma = find_exact_vma(mm, vm_start, vm_end);
2191         if (vma && vma->vm_file) {
2192                 *path = vma->vm_file->f_path;
2193                 path_get(path);
2194                 rc = 0;
2195         }
2196         mmap_read_unlock(mm);
2197
2198 out_mmput:
2199         mmput(mm);
2200 out:
2201         return rc;
2202 }
2203
2204 struct map_files_info {
2205         unsigned long   start;
2206         unsigned long   end;
2207         fmode_t         mode;
2208 };
2209
2210 /*
2211  * Only allow CAP_SYS_ADMIN and CAP_CHECKPOINT_RESTORE to follow the links, due
2212  * to concerns about how the symlinks may be used to bypass permissions on
2213  * ancestor directories in the path to the file in question.
2214  */
2215 static const char *
2216 proc_map_files_get_link(struct dentry *dentry,
2217                         struct inode *inode,
2218                         struct delayed_call *done)
2219 {
2220         if (!checkpoint_restore_ns_capable(&init_user_ns))
2221                 return ERR_PTR(-EPERM);
2222
2223         return proc_pid_get_link(dentry, inode, done);
2224 }
2225
2226 /*
2227  * Identical to proc_pid_link_inode_operations except for get_link()
2228  */
2229 static const struct inode_operations proc_map_files_link_inode_operations = {
2230         .readlink       = proc_pid_readlink,
2231         .get_link       = proc_map_files_get_link,
2232         .setattr        = proc_setattr,
2233 };
2234
2235 static struct dentry *
2236 proc_map_files_instantiate(struct dentry *dentry,
2237                            struct task_struct *task, const void *ptr)
2238 {
2239         fmode_t mode = (fmode_t)(unsigned long)ptr;
2240         struct proc_inode *ei;
2241         struct inode *inode;
2242
2243         inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK |
2244                                     ((mode & FMODE_READ ) ? S_IRUSR : 0) |
2245                                     ((mode & FMODE_WRITE) ? S_IWUSR : 0));
2246         if (!inode)
2247                 return ERR_PTR(-ENOENT);
2248
2249         ei = PROC_I(inode);
2250         ei->op.proc_get_link = map_files_get_link;
2251
2252         inode->i_op = &proc_map_files_link_inode_operations;
2253         inode->i_size = 64;
2254
2255         d_set_d_op(dentry, &tid_map_files_dentry_operations);
2256         return d_splice_alias(inode, dentry);
2257 }
2258
2259 static struct dentry *proc_map_files_lookup(struct inode *dir,
2260                 struct dentry *dentry, unsigned int flags)
2261 {
2262         unsigned long vm_start, vm_end;
2263         struct vm_area_struct *vma;
2264         struct task_struct *task;
2265         struct dentry *result;
2266         struct mm_struct *mm;
2267
2268         result = ERR_PTR(-ENOENT);
2269         task = get_proc_task(dir);
2270         if (!task)
2271                 goto out;
2272
2273         result = ERR_PTR(-EACCES);
2274         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2275                 goto out_put_task;
2276
2277         result = ERR_PTR(-ENOENT);
2278         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2279                 goto out_put_task;
2280
2281         mm = get_task_mm(task);
2282         if (!mm)
2283                 goto out_put_task;
2284
2285         result = ERR_PTR(-EINTR);
2286         if (mmap_read_lock_killable(mm))
2287                 goto out_put_mm;
2288
2289         result = ERR_PTR(-ENOENT);
2290         vma = find_exact_vma(mm, vm_start, vm_end);
2291         if (!vma)
2292                 goto out_no_vma;
2293
2294         if (vma->vm_file)
2295                 result = proc_map_files_instantiate(dentry, task,
2296                                 (void *)(unsigned long)vma->vm_file->f_mode);
2297
2298 out_no_vma:
2299         mmap_read_unlock(mm);
2300 out_put_mm:
2301         mmput(mm);
2302 out_put_task:
2303         put_task_struct(task);
2304 out:
2305         return result;
2306 }
2307
2308 static const struct inode_operations proc_map_files_inode_operations = {
2309         .lookup         = proc_map_files_lookup,
2310         .permission     = proc_fd_permission,
2311         .setattr        = proc_setattr,
2312 };
2313
2314 static int
2315 proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2316 {
2317         struct vm_area_struct *vma;
2318         struct task_struct *task;
2319         struct mm_struct *mm;
2320         unsigned long nr_files, pos, i;
2321         GENRADIX(struct map_files_info) fa;
2322         struct map_files_info *p;
2323         int ret;
2324
2325         genradix_init(&fa);
2326
2327         ret = -ENOENT;
2328         task = get_proc_task(file_inode(file));
2329         if (!task)
2330                 goto out;
2331
2332         ret = -EACCES;
2333         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2334                 goto out_put_task;
2335
2336         ret = 0;
2337         if (!dir_emit_dots(file, ctx))
2338                 goto out_put_task;
2339
2340         mm = get_task_mm(task);
2341         if (!mm)
2342                 goto out_put_task;
2343
2344         ret = mmap_read_lock_killable(mm);
2345         if (ret) {
2346                 mmput(mm);
2347                 goto out_put_task;
2348         }
2349
2350         nr_files = 0;
2351
2352         /*
2353          * We need two passes here:
2354          *
2355          *  1) Collect vmas of mapped files with mmap_lock taken
2356          *  2) Release mmap_lock and instantiate entries
2357          *
2358          * otherwise we get lockdep complained, since filldir()
2359          * routine might require mmap_lock taken in might_fault().
2360          */
2361
2362         for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2363                 if (!vma->vm_file)
2364                         continue;
2365                 if (++pos <= ctx->pos)
2366                         continue;
2367
2368                 p = genradix_ptr_alloc(&fa, nr_files++, GFP_KERNEL);
2369                 if (!p) {
2370                         ret = -ENOMEM;
2371                         mmap_read_unlock(mm);
2372                         mmput(mm);
2373                         goto out_put_task;
2374                 }
2375
2376                 p->start = vma->vm_start;
2377                 p->end = vma->vm_end;
2378                 p->mode = vma->vm_file->f_mode;
2379         }
2380         mmap_read_unlock(mm);
2381         mmput(mm);
2382
2383         for (i = 0; i < nr_files; i++) {
2384                 char buf[4 * sizeof(long) + 2]; /* max: %lx-%lx\0 */
2385                 unsigned int len;
2386
2387                 p = genradix_ptr(&fa, i);
2388                 len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);
2389                 if (!proc_fill_cache(file, ctx,
2390                                       buf, len,
2391                                       proc_map_files_instantiate,
2392                                       task,
2393                                       (void *)(unsigned long)p->mode))
2394                         break;
2395                 ctx->pos++;
2396         }
2397
2398 out_put_task:
2399         put_task_struct(task);
2400 out:
2401         genradix_free(&fa);
2402         return ret;
2403 }
2404
2405 static const struct file_operations proc_map_files_operations = {
2406         .read           = generic_read_dir,
2407         .iterate_shared = proc_map_files_readdir,
2408         .llseek         = generic_file_llseek,
2409 };
2410
2411 #if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
2412 struct timers_private {
2413         struct pid *pid;
2414         struct task_struct *task;
2415         struct sighand_struct *sighand;
2416         struct pid_namespace *ns;
2417         unsigned long flags;
2418 };
2419
2420 static void *timers_start(struct seq_file *m, loff_t *pos)
2421 {
2422         struct timers_private *tp = m->private;
2423
2424         tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2425         if (!tp->task)
2426                 return ERR_PTR(-ESRCH);
2427
2428         tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2429         if (!tp->sighand)
2430                 return ERR_PTR(-ESRCH);
2431
2432         return seq_list_start(&tp->task->signal->posix_timers, *pos);
2433 }
2434
2435 static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2436 {
2437         struct timers_private *tp = m->private;
2438         return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2439 }
2440
2441 static void timers_stop(struct seq_file *m, void *v)
2442 {
2443         struct timers_private *tp = m->private;
2444
2445         if (tp->sighand) {
2446                 unlock_task_sighand(tp->task, &tp->flags);
2447                 tp->sighand = NULL;
2448         }
2449
2450         if (tp->task) {
2451                 put_task_struct(tp->task);
2452                 tp->task = NULL;
2453         }
2454 }
2455
2456 static int show_timer(struct seq_file *m, void *v)
2457 {
2458         struct k_itimer *timer;
2459         struct timers_private *tp = m->private;
2460         int notify;
2461         static const char * const nstr[] = {
2462                 [SIGEV_SIGNAL] = "signal",
2463                 [SIGEV_NONE] = "none",
2464                 [SIGEV_THREAD] = "thread",
2465         };
2466
2467         timer = list_entry((struct list_head *)v, struct k_itimer, list);
2468         notify = timer->it_sigev_notify;
2469
2470         seq_printf(m, "ID: %d\n", timer->it_id);
2471         seq_printf(m, "signal: %d/%px\n",
2472                    timer->sigq->info.si_signo,
2473                    timer->sigq->info.si_value.sival_ptr);
2474         seq_printf(m, "notify: %s/%s.%d\n",
2475                    nstr[notify & ~SIGEV_THREAD_ID],
2476                    (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2477                    pid_nr_ns(timer->it_pid, tp->ns));
2478         seq_printf(m, "ClockID: %d\n", timer->it_clock);
2479
2480         return 0;
2481 }
2482
2483 static const struct seq_operations proc_timers_seq_ops = {
2484         .start  = timers_start,
2485         .next   = timers_next,
2486         .stop   = timers_stop,
2487         .show   = show_timer,
2488 };
2489
2490 static int proc_timers_open(struct inode *inode, struct file *file)
2491 {
2492         struct timers_private *tp;
2493
2494         tp = __seq_open_private(file, &proc_timers_seq_ops,
2495                         sizeof(struct timers_private));
2496         if (!tp)
2497                 return -ENOMEM;
2498
2499         tp->pid = proc_pid(inode);
2500         tp->ns = proc_pid_ns(inode->i_sb);
2501         return 0;
2502 }
2503
2504 static const struct file_operations proc_timers_operations = {
2505         .open           = proc_timers_open,
2506         .read           = seq_read,
2507         .llseek         = seq_lseek,
2508         .release        = seq_release_private,
2509 };
2510 #endif
2511
2512 static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2513                                         size_t count, loff_t *offset)
2514 {
2515         struct inode *inode = file_inode(file);
2516         struct task_struct *p;
2517         u64 slack_ns;
2518         int err;
2519
2520         err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2521         if (err < 0)
2522                 return err;
2523
2524         p = get_proc_task(inode);
2525         if (!p)
2526                 return -ESRCH;
2527
2528         if (p != current) {
2529                 rcu_read_lock();
2530                 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
2531                         rcu_read_unlock();
2532                         count = -EPERM;
2533                         goto out;
2534                 }
2535                 rcu_read_unlock();
2536
2537                 err = security_task_setscheduler(p);
2538                 if (err) {
2539                         count = err;
2540                         goto out;
2541                 }
2542         }
2543
2544         task_lock(p);
2545         if (slack_ns == 0)
2546                 p->timer_slack_ns = p->default_timer_slack_ns;
2547         else
2548                 p->timer_slack_ns = slack_ns;
2549         task_unlock(p);
2550
2551 out:
2552         put_task_struct(p);
2553
2554         return count;
2555 }
2556
2557 static int timerslack_ns_show(struct seq_file *m, void *v)
2558 {
2559         struct inode *inode = m->private;
2560         struct task_struct *p;
2561         int err = 0;
2562
2563         p = get_proc_task(inode);
2564         if (!p)
2565                 return -ESRCH;
2566
2567         if (p != current) {
2568                 rcu_read_lock();
2569                 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
2570                         rcu_read_unlock();
2571                         err = -EPERM;
2572                         goto out;
2573                 }
2574                 rcu_read_unlock();
2575
2576                 err = security_task_getscheduler(p);
2577                 if (err)
2578                         goto out;
2579         }
2580
2581         task_lock(p);
2582         seq_printf(m, "%llu\n", p->timer_slack_ns);
2583         task_unlock(p);
2584
2585 out:
2586         put_task_struct(p);
2587
2588         return err;
2589 }
2590
2591 static int timerslack_ns_open(struct inode *inode, struct file *filp)
2592 {
2593         return single_open(filp, timerslack_ns_show, inode);
2594 }
2595
2596 static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2597         .open           = timerslack_ns_open,
2598         .read           = seq_read,
2599         .write          = timerslack_ns_write,
2600         .llseek         = seq_lseek,
2601         .release        = single_release,
2602 };
2603
2604 static struct dentry *proc_pident_instantiate(struct dentry *dentry,
2605         struct task_struct *task, const void *ptr)
2606 {
2607         const struct pid_entry *p = ptr;
2608         struct inode *inode;
2609         struct proc_inode *ei;
2610
2611         inode = proc_pid_make_inode(dentry->d_sb, task, p->mode);
2612         if (!inode)
2613                 return ERR_PTR(-ENOENT);
2614
2615         ei = PROC_I(inode);
2616         if (S_ISDIR(inode->i_mode))
2617                 set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2618         if (p->iop)
2619                 inode->i_op = p->iop;
2620         if (p->fop)
2621                 inode->i_fop = p->fop;
2622         ei->op = p->op;
2623         pid_update_inode(task, inode);
2624         d_set_d_op(dentry, &pid_dentry_operations);
2625         return d_splice_alias(inode, dentry);
2626 }
2627
2628 static struct dentry *proc_pident_lookup(struct inode *dir,
2629                                          struct dentry *dentry,
2630                                          const struct pid_entry *p,
2631                                          const struct pid_entry *end)
2632 {
2633         struct task_struct *task = get_proc_task(dir);
2634         struct dentry *res = ERR_PTR(-ENOENT);
2635
2636         if (!task)
2637                 goto out_no_task;
2638
2639         /*
2640          * Yes, it does not scale. And it should not. Don't add
2641          * new entries into /proc/<tgid>/ without very good reasons.
2642          */
2643         for (; p < end; p++) {
2644                 if (p->len != dentry->d_name.len)
2645                         continue;
2646                 if (!memcmp(dentry->d_name.name, p->name, p->len)) {
2647                         res = proc_pident_instantiate(dentry, task, p);
2648                         break;
2649                 }
2650         }
2651         put_task_struct(task);
2652 out_no_task:
2653         return res;
2654 }
2655
2656 static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2657                 const struct pid_entry *ents, unsigned int nents)
2658 {
2659         struct task_struct *task = get_proc_task(file_inode(file));
2660         const struct pid_entry *p;
2661
2662         if (!task)
2663                 return -ENOENT;
2664
2665         if (!dir_emit_dots(file, ctx))
2666                 goto out;
2667
2668         if (ctx->pos >= nents + 2)
2669                 goto out;
2670
2671         for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
2672                 if (!proc_fill_cache(file, ctx, p->name, p->len,
2673                                 proc_pident_instantiate, task, p))
2674                         break;
2675                 ctx->pos++;
2676         }
2677 out:
2678         put_task_struct(task);
2679         return 0;
2680 }
2681
2682 #ifdef CONFIG_SECURITY
2683 static int proc_pid_attr_open(struct inode *inode, struct file *file)
2684 {
2685         file->private_data = NULL;
2686         __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
2687         return 0;
2688 }
2689
2690 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2691                                   size_t count, loff_t *ppos)
2692 {
2693         struct inode * inode = file_inode(file);
2694         char *p = NULL;
2695         ssize_t length;
2696         struct task_struct *task = get_proc_task(inode);
2697
2698         if (!task)
2699                 return -ESRCH;
2700
2701         length = security_getprocattr(task, PROC_I(inode)->op.lsm,
2702                                       (char*)file->f_path.dentry->d_name.name,
2703                                       &p);
2704         put_task_struct(task);
2705         if (length > 0)
2706                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2707         kfree(p);
2708         return length;
2709 }
2710
2711 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2712                                    size_t count, loff_t *ppos)
2713 {
2714         struct inode * inode = file_inode(file);
2715         struct task_struct *task;
2716         void *page;
2717         int rv;
2718
2719         /* A task may only write when it was the opener. */
2720         if (file->private_data != current->mm)
2721                 return -EPERM;
2722
2723         rcu_read_lock();
2724         task = pid_task(proc_pid(inode), PIDTYPE_PID);
2725         if (!task) {
2726                 rcu_read_unlock();
2727                 return -ESRCH;
2728         }
2729         /* A task may only write its own attributes. */
2730         if (current != task) {
2731                 rcu_read_unlock();
2732                 return -EACCES;
2733         }
2734         /* Prevent changes to overridden credentials. */
2735         if (current_cred() != current_real_cred()) {
2736                 rcu_read_unlock();
2737                 return -EBUSY;
2738         }
2739         rcu_read_unlock();
2740
2741         if (count > PAGE_SIZE)
2742                 count = PAGE_SIZE;
2743
2744         /* No partial writes. */
2745         if (*ppos != 0)
2746                 return -EINVAL;
2747
2748         page = memdup_user(buf, count);
2749         if (IS_ERR(page)) {
2750                 rv = PTR_ERR(page);
2751                 goto out;
2752         }
2753
2754         /* Guard against adverse ptrace interaction */
2755         rv = mutex_lock_interruptible(&current->signal->cred_guard_mutex);
2756         if (rv < 0)
2757                 goto out_free;
2758
2759         rv = security_setprocattr(PROC_I(inode)->op.lsm,
2760                                   file->f_path.dentry->d_name.name, page,
2761                                   count);
2762         mutex_unlock(&current->signal->cred_guard_mutex);
2763 out_free:
2764         kfree(page);
2765 out:
2766         return rv;
2767 }
2768
2769 static const struct file_operations proc_pid_attr_operations = {
2770         .open           = proc_pid_attr_open,
2771         .read           = proc_pid_attr_read,
2772         .write          = proc_pid_attr_write,
2773         .llseek         = generic_file_llseek,
2774         .release        = mem_release,
2775 };
2776
2777 #define LSM_DIR_OPS(LSM) \
2778 static int proc_##LSM##_attr_dir_iterate(struct file *filp, \
2779                              struct dir_context *ctx) \
2780 { \
2781         return proc_pident_readdir(filp, ctx, \
2782                                    LSM##_attr_dir_stuff, \
2783                                    ARRAY_SIZE(LSM##_attr_dir_stuff)); \
2784 } \
2785 \
2786 static const struct file_operations proc_##LSM##_attr_dir_ops = { \
2787         .read           = generic_read_dir, \
2788         .iterate        = proc_##LSM##_attr_dir_iterate, \
2789         .llseek         = default_llseek, \
2790 }; \
2791 \
2792 static struct dentry *proc_##LSM##_attr_dir_lookup(struct inode *dir, \
2793                                 struct dentry *dentry, unsigned int flags) \
2794 { \
2795         return proc_pident_lookup(dir, dentry, \
2796                                   LSM##_attr_dir_stuff, \
2797                                   LSM##_attr_dir_stuff + ARRAY_SIZE(LSM##_attr_dir_stuff)); \
2798 } \
2799 \
2800 static const struct inode_operations proc_##LSM##_attr_dir_inode_ops = { \
2801         .lookup         = proc_##LSM##_attr_dir_lookup, \
2802         .getattr        = pid_getattr, \
2803         .setattr        = proc_setattr, \
2804 }
2805
2806 #ifdef CONFIG_SECURITY_SMACK
2807 static const struct pid_entry smack_attr_dir_stuff[] = {
2808         ATTR("smack", "current",        0666),
2809 };
2810 LSM_DIR_OPS(smack);
2811 #endif
2812
2813 #ifdef CONFIG_SECURITY_APPARMOR
2814 static const struct pid_entry apparmor_attr_dir_stuff[] = {
2815         ATTR("apparmor", "current",     0666),
2816         ATTR("apparmor", "prev",        0444),
2817         ATTR("apparmor", "exec",        0666),
2818 };
2819 LSM_DIR_OPS(apparmor);
2820 #endif
2821
2822 static const struct pid_entry attr_dir_stuff[] = {
2823         ATTR(NULL, "current",           0666),
2824         ATTR(NULL, "prev",              0444),
2825         ATTR(NULL, "exec",              0666),
2826         ATTR(NULL, "fscreate",          0666),
2827         ATTR(NULL, "keycreate",         0666),
2828         ATTR(NULL, "sockcreate",        0666),
2829 #ifdef CONFIG_SECURITY_SMACK
2830         DIR("smack",                    0555,
2831             proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
2832 #endif
2833 #ifdef CONFIG_SECURITY_APPARMOR
2834         DIR("apparmor",                 0555,
2835             proc_apparmor_attr_dir_inode_ops, proc_apparmor_attr_dir_ops),
2836 #endif
2837 };
2838
2839 static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2840 {
2841         return proc_pident_readdir(file, ctx,
2842                                    attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2843 }
2844
2845 static const struct file_operations proc_attr_dir_operations = {
2846         .read           = generic_read_dir,
2847         .iterate_shared = proc_attr_dir_readdir,
2848         .llseek         = generic_file_llseek,
2849 };
2850
2851 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2852                                 struct dentry *dentry, unsigned int flags)
2853 {
2854         return proc_pident_lookup(dir, dentry,
2855                                   attr_dir_stuff,
2856                                   attr_dir_stuff + ARRAY_SIZE(attr_dir_stuff));
2857 }
2858
2859 static const struct inode_operations proc_attr_dir_inode_operations = {
2860         .lookup         = proc_attr_dir_lookup,
2861         .getattr        = pid_getattr,
2862         .setattr        = proc_setattr,
2863 };
2864
2865 #endif
2866
2867 #ifdef CONFIG_ELF_CORE
2868 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2869                                          size_t count, loff_t *ppos)
2870 {
2871         struct task_struct *task = get_proc_task(file_inode(file));
2872         struct mm_struct *mm;
2873         char buffer[PROC_NUMBUF];
2874         size_t len;
2875         int ret;
2876
2877         if (!task)
2878                 return -ESRCH;
2879
2880         ret = 0;
2881         mm = get_task_mm(task);
2882         if (mm) {
2883                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2884                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2885                                 MMF_DUMP_FILTER_SHIFT));
2886                 mmput(mm);
2887                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2888         }
2889
2890         put_task_struct(task);
2891
2892         return ret;
2893 }
2894
2895 static ssize_t proc_coredump_filter_write(struct file *file,
2896                                           const char __user *buf,
2897                                           size_t count,
2898                                           loff_t *ppos)
2899 {
2900         struct task_struct *task;
2901         struct mm_struct *mm;
2902         unsigned int val;
2903         int ret;
2904         int i;
2905         unsigned long mask;
2906
2907         ret = kstrtouint_from_user(buf, count, 0, &val);
2908         if (ret < 0)
2909                 return ret;
2910
2911         ret = -ESRCH;
2912         task = get_proc_task(file_inode(file));
2913         if (!task)
2914                 goto out_no_task;
2915
2916         mm = get_task_mm(task);
2917         if (!mm)
2918                 goto out_no_mm;
2919         ret = 0;
2920
2921         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2922                 if (val & mask)
2923                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2924                 else
2925                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2926         }
2927
2928         mmput(mm);
2929  out_no_mm:
2930         put_task_struct(task);
2931  out_no_task:
2932         if (ret < 0)
2933                 return ret;
2934         return count;
2935 }
2936
2937 static const struct file_operations proc_coredump_filter_operations = {
2938         .read           = proc_coredump_filter_read,
2939         .write          = proc_coredump_filter_write,
2940         .llseek         = generic_file_llseek,
2941 };
2942 #endif
2943
2944 #ifdef CONFIG_TASK_IO_ACCOUNTING
2945 static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2946 {
2947         struct task_io_accounting acct = task->ioac;
2948         unsigned long flags;
2949         int result;
2950
2951         result = down_read_killable(&task->signal->exec_update_lock);
2952         if (result)
2953                 return result;
2954
2955         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2956                 result = -EACCES;
2957                 goto out_unlock;
2958         }
2959
2960         if (whole && lock_task_sighand(task, &flags)) {
2961                 struct task_struct *t = task;
2962
2963                 task_io_accounting_add(&acct, &task->signal->ioac);
2964                 while_each_thread(task, t)
2965                         task_io_accounting_add(&acct, &t->ioac);
2966
2967                 unlock_task_sighand(task, &flags);
2968         }
2969         seq_printf(m,
2970                    "rchar: %llu\n"
2971                    "wchar: %llu\n"
2972                    "syscr: %llu\n"
2973                    "syscw: %llu\n"
2974                    "read_bytes: %llu\n"
2975                    "write_bytes: %llu\n"
2976                    "cancelled_write_bytes: %llu\n",
2977                    (unsigned long long)acct.rchar,
2978                    (unsigned long long)acct.wchar,
2979                    (unsigned long long)acct.syscr,
2980                    (unsigned long long)acct.syscw,
2981                    (unsigned long long)acct.read_bytes,
2982                    (unsigned long long)acct.write_bytes,
2983                    (unsigned long long)acct.cancelled_write_bytes);
2984         result = 0;
2985
2986 out_unlock:
2987         up_read(&task->signal->exec_update_lock);
2988         return result;
2989 }
2990
2991 static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2992                                   struct pid *pid, struct task_struct *task)
2993 {
2994         return do_io_accounting(task, m, 0);
2995 }
2996
2997 static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2998                                    struct pid *pid, struct task_struct *task)
2999 {
3000         return do_io_accounting(task, m, 1);
3001 }
3002 #endif /* CONFIG_TASK_IO_ACCOUNTING */
3003
3004 #ifdef CONFIG_USER_NS
3005 static int proc_id_map_open(struct inode *inode, struct file *file,
3006         const struct seq_operations *seq_ops)
3007 {
3008         struct user_namespace *ns = NULL;
3009         struct task_struct *task;
3010         struct seq_file *seq;
3011         int ret = -EINVAL;
3012
3013         task = get_proc_task(inode);
3014         if (task) {
3015                 rcu_read_lock();
3016                 ns = get_user_ns(task_cred_xxx(task, user_ns));
3017                 rcu_read_unlock();
3018                 put_task_struct(task);
3019         }
3020         if (!ns)
3021                 goto err;
3022
3023         ret = seq_open(file, seq_ops);
3024         if (ret)
3025                 goto err_put_ns;
3026
3027         seq = file->private_data;
3028         seq->private = ns;
3029
3030         return 0;
3031 err_put_ns:
3032         put_user_ns(ns);
3033 err:
3034         return ret;
3035 }
3036
3037 static int proc_id_map_release(struct inode *inode, struct file *file)
3038 {
3039         struct seq_file *seq = file->private_data;
3040         struct user_namespace *ns = seq->private;
3041         put_user_ns(ns);
3042         return seq_release(inode, file);
3043 }
3044
3045 static int proc_uid_map_open(struct inode *inode, struct file *file)
3046 {
3047         return proc_id_map_open(inode, file, &proc_uid_seq_operations);
3048 }
3049
3050 static int proc_gid_map_open(struct inode *inode, struct file *file)
3051 {
3052         return proc_id_map_open(inode, file, &proc_gid_seq_operations);
3053 }
3054
3055 static int proc_projid_map_open(struct inode *inode, struct file *file)
3056 {
3057         return proc_id_map_open(inode, file, &proc_projid_seq_operations);
3058 }
3059
3060 static const struct file_operations proc_uid_map_operations = {
3061         .open           = proc_uid_map_open,
3062         .write          = proc_uid_map_write,
3063         .read           = seq_read,
3064         .llseek         = seq_lseek,
3065         .release        = proc_id_map_release,
3066 };
3067
3068 static const struct file_operations proc_gid_map_operations = {
3069         .open           = proc_gid_map_open,
3070         .write          = proc_gid_map_write,
3071         .read           = seq_read,
3072         .llseek         = seq_lseek,
3073         .release        = proc_id_map_release,
3074 };
3075
3076 static const struct file_operations proc_projid_map_operations = {
3077         .open           = proc_projid_map_open,
3078         .write          = proc_projid_map_write,
3079         .read           = seq_read,
3080         .llseek         = seq_lseek,
3081         .release        = proc_id_map_release,
3082 };
3083
3084 static int proc_setgroups_open(struct inode *inode, struct file *file)
3085 {
3086         struct user_namespace *ns = NULL;
3087         struct task_struct *task;
3088         int ret;
3089
3090         ret = -ESRCH;
3091         task = get_proc_task(inode);
3092         if (task) {
3093                 rcu_read_lock();
3094                 ns = get_user_ns(task_cred_xxx(task, user_ns));
3095                 rcu_read_unlock();
3096                 put_task_struct(task);
3097         }
3098         if (!ns)
3099                 goto err;
3100
3101         if (file->f_mode & FMODE_WRITE) {
3102                 ret = -EACCES;
3103                 if (!ns_capable(ns, CAP_SYS_ADMIN))
3104                         goto err_put_ns;
3105         }
3106
3107         ret = single_open(file, &proc_setgroups_show, ns);
3108         if (ret)
3109                 goto err_put_ns;
3110
3111         return 0;
3112 err_put_ns:
3113         put_user_ns(ns);
3114 err:
3115         return ret;
3116 }
3117
3118 static int proc_setgroups_release(struct inode *inode, struct file *file)
3119 {
3120         struct seq_file *seq = file->private_data;
3121         struct user_namespace *ns = seq->private;
3122         int ret = single_release(inode, file);
3123         put_user_ns(ns);
3124         return ret;
3125 }
3126
3127 static const struct file_operations proc_setgroups_operations = {
3128         .open           = proc_setgroups_open,
3129         .write          = proc_setgroups_write,
3130         .read           = seq_read,
3131         .llseek         = seq_lseek,
3132         .release        = proc_setgroups_release,
3133 };
3134 #endif /* CONFIG_USER_NS */
3135
3136 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
3137                                 struct pid *pid, struct task_struct *task)
3138 {
3139         int err = lock_trace(task);
3140         if (!err) {
3141                 seq_printf(m, "%08x\n", task->personality);
3142                 unlock_trace(task);
3143         }
3144         return err;
3145 }
3146
3147 #ifdef CONFIG_LIVEPATCH
3148 static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns,
3149                                 struct pid *pid, struct task_struct *task)
3150 {
3151         seq_printf(m, "%d\n", task->patch_state);
3152         return 0;
3153 }
3154 #endif /* CONFIG_LIVEPATCH */
3155
3156 #ifdef CONFIG_STACKLEAK_METRICS
3157 static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns,
3158                                 struct pid *pid, struct task_struct *task)
3159 {
3160         unsigned long prev_depth = THREAD_SIZE -
3161                                 (task->prev_lowest_stack & (THREAD_SIZE - 1));
3162         unsigned long depth = THREAD_SIZE -
3163                                 (task->lowest_stack & (THREAD_SIZE - 1));
3164
3165         seq_printf(m, "previous stack depth: %lu\nstack depth: %lu\n",
3166                                                         prev_depth, depth);
3167         return 0;
3168 }
3169 #endif /* CONFIG_STACKLEAK_METRICS */
3170
3171 /*
3172  * Thread groups
3173  */
3174 static const struct file_operations proc_task_operations;
3175 static const struct inode_operations proc_task_inode_operations;
3176
3177 static const struct pid_entry tgid_base_stuff[] = {
3178         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
3179         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3180         DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
3181         DIR("fdinfo",     S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3182         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3183 #ifdef CONFIG_NET
3184         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3185 #endif
3186         REG("environ",    S_IRUSR, proc_environ_operations),
3187         REG("auxv",       S_IRUSR, proc_auxv_operations),
3188         ONE("status",     S_IRUGO, proc_pid_status),
3189         ONE("personality", S_IRUSR, proc_pid_personality),
3190         ONE("limits",     S_IRUGO, proc_pid_limits),
3191 #ifdef CONFIG_SCHED_DEBUG
3192         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3193 #endif
3194 #ifdef CONFIG_SCHED_AUTOGROUP
3195         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
3196 #endif
3197 #ifdef CONFIG_TIME_NS
3198         REG("timens_offsets",  S_IRUGO|S_IWUSR, proc_timens_offsets_operations),
3199 #endif
3200         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3201 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3202         ONE("syscall",    S_IRUSR, proc_pid_syscall),
3203 #endif
3204         REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
3205         ONE("stat",       S_IRUGO, proc_tgid_stat),
3206         ONE("statm",      S_IRUGO, proc_pid_statm),
3207         REG("maps",       S_IRUGO, proc_pid_maps_operations),
3208 #ifdef CONFIG_NUMA
3209         REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
3210 #endif
3211         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
3212         LNK("cwd",        proc_cwd_link),
3213         LNK("root",       proc_root_link),
3214         LNK("exe",        proc_exe_link),
3215         REG("mounts",     S_IRUGO, proc_mounts_operations),
3216         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3217         REG("mountstats", S_IRUSR, proc_mountstats_operations),
3218 #ifdef CONFIG_PROC_PAGE_MONITOR
3219         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3220         REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
3221         REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3222         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3223 #endif
3224 #ifdef CONFIG_SECURITY
3225         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3226 #endif
3227 #ifdef CONFIG_KALLSYMS
3228         ONE("wchan",      S_IRUGO, proc_pid_wchan),
3229 #endif
3230 #ifdef CONFIG_STACKTRACE
3231         ONE("stack",      S_IRUSR, proc_pid_stack),
3232 #endif
3233 #ifdef CONFIG_SCHED_INFO
3234         ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
3235 #endif
3236 #ifdef CONFIG_LATENCYTOP
3237         REG("latency",  S_IRUGO, proc_lstats_operations),
3238 #endif
3239 #ifdef CONFIG_PROC_PID_CPUSET
3240         ONE("cpuset",     S_IRUGO, proc_cpuset_show),
3241 #endif
3242 #ifdef CONFIG_CGROUPS
3243         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3244 #endif
3245 #ifdef CONFIG_PROC_CPU_RESCTRL
3246         ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
3247 #endif
3248         ONE("oom_score",  S_IRUGO, proc_oom_score),
3249         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3250         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3251 #ifdef CONFIG_AUDIT
3252         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
3253         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3254 #endif
3255 #ifdef CONFIG_FAULT_INJECTION
3256         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3257         REG("fail-nth", 0644, proc_fail_nth_operations),
3258 #endif
3259 #ifdef CONFIG_ELF_CORE
3260         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
3261 #endif
3262 #ifdef CONFIG_TASK_IO_ACCOUNTING
3263         ONE("io",       S_IRUSR, proc_tgid_io_accounting),
3264 #endif
3265 #ifdef CONFIG_USER_NS
3266         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3267         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3268         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3269         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3270 #endif
3271 #if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
3272         REG("timers",     S_IRUGO, proc_timers_operations),
3273 #endif
3274         REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
3275 #ifdef CONFIG_LIVEPATCH
3276         ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3277 #endif
3278 #ifdef CONFIG_STACKLEAK_METRICS
3279         ONE("stack_depth", S_IRUGO, proc_stack_depth),
3280 #endif
3281 #ifdef CONFIG_PROC_PID_ARCH_STATUS
3282         ONE("arch_status", S_IRUGO, proc_pid_arch_status),
3283 #endif
3284 #ifdef CONFIG_SECCOMP_CACHE_DEBUG
3285         ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
3286 #endif
3287 };
3288
3289 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
3290 {
3291         return proc_pident_readdir(file, ctx,
3292                                    tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3293 }
3294
3295 static const struct file_operations proc_tgid_base_operations = {
3296         .read           = generic_read_dir,
3297         .iterate_shared = proc_tgid_base_readdir,
3298         .llseek         = generic_file_llseek,
3299 };
3300
3301 struct pid *tgid_pidfd_to_pid(const struct file *file)
3302 {
3303         if (file->f_op != &proc_tgid_base_operations)
3304                 return ERR_PTR(-EBADF);
3305
3306         return proc_pid(file_inode(file));
3307 }
3308
3309 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3310 {
3311         return proc_pident_lookup(dir, dentry,
3312                                   tgid_base_stuff,
3313                                   tgid_base_stuff + ARRAY_SIZE(tgid_base_stuff));
3314 }
3315
3316 static const struct inode_operations proc_tgid_base_inode_operations = {
3317         .lookup         = proc_tgid_base_lookup,
3318         .getattr        = pid_getattr,
3319         .setattr        = proc_setattr,
3320         .permission     = proc_pid_permission,
3321 };
3322
3323 /**
3324  * proc_flush_pid -  Remove dcache entries for @pid from the /proc dcache.
3325  * @pid: pid that should be flushed.
3326  *
3327  * This function walks a list of inodes (that belong to any proc
3328  * filesystem) that are attached to the pid and flushes them from
3329  * the dentry cache.
3330  *
3331  * It is safe and reasonable to cache /proc entries for a task until
3332  * that task exits.  After that they just clog up the dcache with
3333  * useless entries, possibly causing useful dcache entries to be
3334  * flushed instead.  This routine is provided to flush those useless
3335  * dcache entries when a process is reaped.
3336  *
3337  * NOTE: This routine is just an optimization so it does not guarantee
3338  *       that no dcache entries will exist after a process is reaped
3339  *       it just makes it very unlikely that any will persist.
3340  */
3341
3342 void proc_flush_pid(struct pid *pid)
3343 {
3344         proc_invalidate_siblings_dcache(&pid->inodes, &pid->lock);
3345 }
3346
3347 static struct dentry *proc_pid_instantiate(struct dentry * dentry,
3348                                    struct task_struct *task, const void *ptr)
3349 {
3350         struct inode *inode;
3351
3352         inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3353         if (!inode)
3354                 return ERR_PTR(-ENOENT);
3355
3356         inode->i_op = &proc_tgid_base_inode_operations;
3357         inode->i_fop = &proc_tgid_base_operations;
3358         inode->i_flags|=S_IMMUTABLE;
3359
3360         set_nlink(inode, nlink_tgid);
3361         pid_update_inode(task, inode);
3362
3363         d_set_d_op(dentry, &pid_dentry_operations);
3364         return d_splice_alias(inode, dentry);
3365 }
3366
3367 struct dentry *proc_pid_lookup(struct dentry *dentry, unsigned int flags)
3368 {
3369         struct task_struct *task;
3370         unsigned tgid;
3371         struct proc_fs_info *fs_info;
3372         struct pid_namespace *ns;
3373         struct dentry *result = ERR_PTR(-ENOENT);
3374
3375         tgid = name_to_int(&dentry->d_name);
3376         if (tgid == ~0U)
3377                 goto out;
3378
3379         fs_info = proc_sb_info(dentry->d_sb);
3380         ns = fs_info->pid_ns;
3381         rcu_read_lock();
3382         task = find_task_by_pid_ns(tgid, ns);
3383         if (task)
3384                 get_task_struct(task);
3385         rcu_read_unlock();
3386         if (!task)
3387                 goto out;
3388
3389         /* Limit procfs to only ptraceable tasks */
3390         if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE) {
3391                 if (!has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS))
3392                         goto out_put_task;
3393         }
3394
3395         result = proc_pid_instantiate(dentry, task, NULL);
3396 out_put_task:
3397         put_task_struct(task);
3398 out:
3399         return result;
3400 }
3401
3402 /*
3403  * Find the first task with tgid >= tgid
3404  *
3405  */
3406 struct tgid_iter {
3407         unsigned int tgid;
3408         struct task_struct *task;
3409 };
3410 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3411 {
3412         struct pid *pid;
3413
3414         if (iter.task)
3415                 put_task_struct(iter.task);
3416         rcu_read_lock();
3417 retry:
3418         iter.task = NULL;
3419         pid = find_ge_pid(iter.tgid, ns);
3420         if (pid) {
3421                 iter.tgid = pid_nr_ns(pid, ns);
3422                 iter.task = pid_task(pid, PIDTYPE_TGID);
3423                 if (!iter.task) {
3424                         iter.tgid += 1;
3425                         goto retry;
3426                 }
3427                 get_task_struct(iter.task);
3428         }
3429         rcu_read_unlock();
3430         return iter;
3431 }
3432
3433 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3434
3435 /* for the /proc/ directory itself, after non-process stuff has been done */
3436 int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3437 {
3438         struct tgid_iter iter;
3439         struct proc_fs_info *fs_info = proc_sb_info(file_inode(file)->i_sb);
3440         struct pid_namespace *ns = proc_pid_ns(file_inode(file)->i_sb);
3441         loff_t pos = ctx->pos;
3442
3443         if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3444                 return 0;
3445
3446         if (pos == TGID_OFFSET - 2) {
3447                 struct inode *inode = d_inode(fs_info->proc_self);
3448                 if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3449                         return 0;
3450                 ctx->pos = pos = pos + 1;
3451         }
3452         if (pos == TGID_OFFSET - 1) {
3453                 struct inode *inode = d_inode(fs_info->proc_thread_self);
3454                 if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3455                         return 0;
3456                 ctx->pos = pos = pos + 1;
3457         }
3458         iter.tgid = pos - TGID_OFFSET;
3459         iter.task = NULL;
3460         for (iter = next_tgid(ns, iter);
3461              iter.task;
3462              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3463                 char name[10 + 1];
3464                 unsigned int len;
3465
3466                 cond_resched();
3467                 if (!has_pid_permissions(fs_info, iter.task, HIDEPID_INVISIBLE))
3468                         continue;
3469
3470                 len = snprintf(name, sizeof(name), "%u", iter.tgid);
3471                 ctx->pos = iter.tgid + TGID_OFFSET;
3472                 if (!proc_fill_cache(file, ctx, name, len,
3473                                      proc_pid_instantiate, iter.task, NULL)) {
3474                         put_task_struct(iter.task);
3475                         return 0;
3476                 }
3477         }
3478         ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3479         return 0;
3480 }
3481
3482 /*
3483  * proc_tid_comm_permission is a special permission function exclusively
3484  * used for the node /proc/<pid>/task/<tid>/comm.
3485  * It bypasses generic permission checks in the case where a task of the same
3486  * task group attempts to access the node.
3487  * The rationale behind this is that glibc and bionic access this node for
3488  * cross thread naming (pthread_set/getname_np(!self)). However, if
3489  * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3490  * which locks out the cross thread naming implementation.
3491  * This function makes sure that the node is always accessible for members of
3492  * same thread group.
3493  */
3494 static int proc_tid_comm_permission(struct user_namespace *mnt_userns,
3495                                     struct inode *inode, int mask)
3496 {
3497         bool is_same_tgroup;
3498         struct task_struct *task;
3499
3500         task = get_proc_task(inode);
3501         if (!task)
3502                 return -ESRCH;
3503         is_same_tgroup = same_thread_group(current, task);
3504         put_task_struct(task);
3505
3506         if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3507                 /* This file (/proc/<pid>/task/<tid>/comm) can always be
3508                  * read or written by the members of the corresponding
3509                  * thread group.
3510                  */
3511                 return 0;
3512         }
3513
3514         return generic_permission(&init_user_ns, inode, mask);
3515 }
3516
3517 static const struct inode_operations proc_tid_comm_inode_operations = {
3518                 .permission = proc_tid_comm_permission,
3519 };
3520
3521 /*
3522  * Tasks
3523  */
3524 static const struct pid_entry tid_base_stuff[] = {
3525         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3526         DIR("fdinfo",    S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3527         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3528 #ifdef CONFIG_NET
3529         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3530 #endif
3531         REG("environ",   S_IRUSR, proc_environ_operations),
3532         REG("auxv",      S_IRUSR, proc_auxv_operations),
3533         ONE("status",    S_IRUGO, proc_pid_status),
3534         ONE("personality", S_IRUSR, proc_pid_personality),
3535         ONE("limits",    S_IRUGO, proc_pid_limits),
3536 #ifdef CONFIG_SCHED_DEBUG
3537         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3538 #endif
3539         NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3540                          &proc_tid_comm_inode_operations,
3541                          &proc_pid_set_comm_operations, {}),
3542 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3543         ONE("syscall",   S_IRUSR, proc_pid_syscall),
3544 #endif
3545         REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3546         ONE("stat",      S_IRUGO, proc_tid_stat),
3547         ONE("statm",     S_IRUGO, proc_pid_statm),
3548         REG("maps",      S_IRUGO, proc_pid_maps_operations),
3549 #ifdef CONFIG_PROC_CHILDREN
3550         REG("children",  S_IRUGO, proc_tid_children_operations),
3551 #endif
3552 #ifdef CONFIG_NUMA
3553         REG("numa_maps", S_IRUGO, proc_pid_numa_maps_operations),
3554 #endif
3555         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3556         LNK("cwd",       proc_cwd_link),
3557         LNK("root",      proc_root_link),
3558         LNK("exe",       proc_exe_link),
3559         REG("mounts",    S_IRUGO, proc_mounts_operations),
3560         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3561 #ifdef CONFIG_PROC_PAGE_MONITOR
3562         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3563         REG("smaps",     S_IRUGO, proc_pid_smaps_operations),
3564         REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3565         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3566 #endif
3567 #ifdef CONFIG_SECURITY
3568         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3569 #endif
3570 #ifdef CONFIG_KALLSYMS
3571         ONE("wchan",     S_IRUGO, proc_pid_wchan),
3572 #endif
3573 #ifdef CONFIG_STACKTRACE
3574         ONE("stack",      S_IRUSR, proc_pid_stack),
3575 #endif
3576 #ifdef CONFIG_SCHED_INFO
3577         ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3578 #endif
3579 #ifdef CONFIG_LATENCYTOP
3580         REG("latency",  S_IRUGO, proc_lstats_operations),
3581 #endif
3582 #ifdef CONFIG_PROC_PID_CPUSET
3583         ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3584 #endif
3585 #ifdef CONFIG_CGROUPS
3586         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3587 #endif
3588 #ifdef CONFIG_PROC_CPU_RESCTRL
3589         ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
3590 #endif
3591         ONE("oom_score", S_IRUGO, proc_oom_score),
3592         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3593         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3594 #ifdef CONFIG_AUDIT
3595         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3596         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3597 #endif
3598 #ifdef CONFIG_FAULT_INJECTION
3599         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3600         REG("fail-nth", 0644, proc_fail_nth_operations),
3601 #endif
3602 #ifdef CONFIG_TASK_IO_ACCOUNTING
3603         ONE("io",       S_IRUSR, proc_tid_io_accounting),
3604 #endif
3605 #ifdef CONFIG_USER_NS
3606         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3607         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3608         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3609         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3610 #endif
3611 #ifdef CONFIG_LIVEPATCH
3612         ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3613 #endif
3614 #ifdef CONFIG_PROC_PID_ARCH_STATUS
3615         ONE("arch_status", S_IRUGO, proc_pid_arch_status),
3616 #endif
3617 #ifdef CONFIG_SECCOMP_CACHE_DEBUG
3618         ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
3619 #endif
3620 };
3621
3622 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3623 {
3624         return proc_pident_readdir(file, ctx,
3625                                    tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3626 }
3627
3628 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3629 {
3630         return proc_pident_lookup(dir, dentry,
3631                                   tid_base_stuff,
3632                                   tid_base_stuff + ARRAY_SIZE(tid_base_stuff));
3633 }
3634
3635 static const struct file_operations proc_tid_base_operations = {
3636         .read           = generic_read_dir,
3637         .iterate_shared = proc_tid_base_readdir,
3638         .llseek         = generic_file_llseek,
3639 };
3640
3641 static const struct inode_operations proc_tid_base_inode_operations = {
3642         .lookup         = proc_tid_base_lookup,
3643         .getattr        = pid_getattr,
3644         .setattr        = proc_setattr,
3645 };
3646
3647 static struct dentry *proc_task_instantiate(struct dentry *dentry,
3648         struct task_struct *task, const void *ptr)
3649 {
3650         struct inode *inode;
3651         inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3652         if (!inode)
3653                 return ERR_PTR(-ENOENT);
3654
3655         inode->i_op = &proc_tid_base_inode_operations;
3656         inode->i_fop = &proc_tid_base_operations;
3657         inode->i_flags |= S_IMMUTABLE;
3658
3659         set_nlink(inode, nlink_tid);
3660         pid_update_inode(task, inode);
3661
3662         d_set_d_op(dentry, &pid_dentry_operations);
3663         return d_splice_alias(inode, dentry);
3664 }
3665
3666 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3667 {
3668         struct task_struct *task;
3669         struct task_struct *leader = get_proc_task(dir);
3670         unsigned tid;
3671         struct proc_fs_info *fs_info;
3672         struct pid_namespace *ns;
3673         struct dentry *result = ERR_PTR(-ENOENT);
3674
3675         if (!leader)
3676                 goto out_no_task;
3677
3678         tid = name_to_int(&dentry->d_name);
3679         if (tid == ~0U)
3680                 goto out;
3681
3682         fs_info = proc_sb_info(dentry->d_sb);
3683         ns = fs_info->pid_ns;
3684         rcu_read_lock();
3685         task = find_task_by_pid_ns(tid, ns);
3686         if (task)
3687                 get_task_struct(task);
3688         rcu_read_unlock();
3689         if (!task)
3690                 goto out;
3691         if (!same_thread_group(leader, task))
3692                 goto out_drop_task;
3693
3694         result = proc_task_instantiate(dentry, task, NULL);
3695 out_drop_task:
3696         put_task_struct(task);
3697 out:
3698         put_task_struct(leader);
3699 out_no_task:
3700         return result;
3701 }
3702
3703 /*
3704  * Find the first tid of a thread group to return to user space.
3705  *
3706  * Usually this is just the thread group leader, but if the users
3707  * buffer was too small or there was a seek into the middle of the
3708  * directory we have more work todo.
3709  *
3710  * In the case of a short read we start with find_task_by_pid.
3711  *
3712  * In the case of a seek we start with the leader and walk nr
3713  * threads past it.
3714  */
3715 static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3716                                         struct pid_namespace *ns)
3717 {
3718         struct task_struct *pos, *task;
3719         unsigned long nr = f_pos;
3720
3721         if (nr != f_pos)        /* 32bit overflow? */
3722                 return NULL;
3723
3724         rcu_read_lock();
3725         task = pid_task(pid, PIDTYPE_PID);
3726         if (!task)
3727                 goto fail;
3728
3729         /* Attempt to start with the tid of a thread */
3730         if (tid && nr) {
3731                 pos = find_task_by_pid_ns(tid, ns);
3732                 if (pos && same_thread_group(pos, task))
3733                         goto found;
3734         }
3735
3736         /* If nr exceeds the number of threads there is nothing todo */
3737         if (nr >= get_nr_threads(task))
3738                 goto fail;
3739
3740         /* If we haven't found our starting place yet start
3741          * with the leader and walk nr threads forward.
3742          */
3743         pos = task = task->group_leader;
3744         do {
3745                 if (!nr--)
3746                         goto found;
3747         } while_each_thread(task, pos);
3748 fail:
3749         pos = NULL;
3750         goto out;
3751 found:
3752         get_task_struct(pos);
3753 out:
3754         rcu_read_unlock();
3755         return pos;
3756 }
3757
3758 /*
3759  * Find the next thread in the thread list.
3760  * Return NULL if there is an error or no next thread.
3761  *
3762  * The reference to the input task_struct is released.
3763  */
3764 static struct task_struct *next_tid(struct task_struct *start)
3765 {
3766         struct task_struct *pos = NULL;
3767         rcu_read_lock();
3768         if (pid_alive(start)) {
3769                 pos = next_thread(start);
3770                 if (thread_group_leader(pos))
3771                         pos = NULL;
3772                 else
3773                         get_task_struct(pos);
3774         }
3775         rcu_read_unlock();
3776         put_task_struct(start);
3777         return pos;
3778 }
3779
3780 /* for the /proc/TGID/task/ directories */
3781 static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3782 {
3783         struct inode *inode = file_inode(file);
3784         struct task_struct *task;
3785         struct pid_namespace *ns;
3786         int tid;
3787
3788         if (proc_inode_is_dead(inode))
3789                 return -ENOENT;
3790
3791         if (!dir_emit_dots(file, ctx))
3792                 return 0;
3793
3794         /* f_version caches the tgid value that the last readdir call couldn't
3795          * return. lseek aka telldir automagically resets f_version to 0.
3796          */
3797         ns = proc_pid_ns(inode->i_sb);
3798         tid = (int)file->f_version;
3799         file->f_version = 0;
3800         for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3801              task;
3802              task = next_tid(task), ctx->pos++) {
3803                 char name[10 + 1];
3804                 unsigned int len;
3805                 tid = task_pid_nr_ns(task, ns);
3806                 len = snprintf(name, sizeof(name), "%u", tid);
3807                 if (!proc_fill_cache(file, ctx, name, len,
3808                                 proc_task_instantiate, task, NULL)) {
3809                         /* returning this tgid failed, save it as the first
3810                          * pid for the next readir call */
3811                         file->f_version = (u64)tid;
3812                         put_task_struct(task);
3813                         break;
3814                 }
3815         }
3816
3817         return 0;
3818 }
3819
3820 static int proc_task_getattr(struct user_namespace *mnt_userns,
3821                              const struct path *path, struct kstat *stat,
3822                              u32 request_mask, unsigned int query_flags)
3823 {
3824         struct inode *inode = d_inode(path->dentry);
3825         struct task_struct *p = get_proc_task(inode);
3826         generic_fillattr(&init_user_ns, inode, stat);
3827
3828         if (p) {
3829                 stat->nlink += get_nr_threads(p);
3830                 put_task_struct(p);
3831         }
3832
3833         return 0;
3834 }
3835
3836 static const struct inode_operations proc_task_inode_operations = {
3837         .lookup         = proc_task_lookup,
3838         .getattr        = proc_task_getattr,
3839         .setattr        = proc_setattr,
3840         .permission     = proc_pid_permission,
3841 };
3842
3843 static const struct file_operations proc_task_operations = {
3844         .read           = generic_read_dir,
3845         .iterate_shared = proc_task_readdir,
3846         .llseek         = generic_file_llseek,
3847 };
3848
3849 void __init set_proc_pid_nlink(void)
3850 {
3851         nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3852         nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3853 }