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