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