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 <bruna.moreira@indt.org.br>
  21 *  Edjard Mota <edjard.mota@indt.org.br>
  22 *  Ilias Biris <ilias.biris@indt.org.br>
  23 *  Mauricio Lin <mauricio.lin@indt.org.br>
  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 <simo.piiroinen@nokia.com>:
  45 *  Smaps information related to shared, private, clean and dirty pages.
  46 *
  47 *  Paul Mundt <paul.mundt@nokia.com>:
  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/printk.h>
  78#include <linux/cache.h>
  79#include <linux/cgroup.h>
  80#include <linux/cpuset.h>
  81#include <linux/audit.h>
  82#include <linux/poll.h>
  83#include <linux/nsproxy.h>
  84#include <linux/oom.h>
  85#include <linux/elf.h>
  86#include <linux/pid_namespace.h>
  87#include <linux/user_namespace.h>
 
  88#include <linux/fs_struct.h>
  89#include <linux/slab.h>
  90#include <linux/sched/autogroup.h>
  91#include <linux/sched/mm.h>
  92#include <linux/sched/coredump.h>
  93#include <linux/sched/debug.h>
  94#include <linux/sched/stat.h>
  95#include <linux/posix-timers.h>
  96#include <linux/time_namespace.h>
  97#include <linux/resctrl.h>
  98#include <linux/cn_proc.h>
  99#include <linux/ksm.h>
 100#include <uapi/linux/lsm.h>
 101#include <trace/events/oom.h>
 102#include "internal.h"
 103#include "fd.h"
 104
 105#include "../../lib/kstrtox.h"
 106
 107/* NOTE:
 108 *	Implementing inode permission operations in /proc is almost
 109 *	certainly an error.  Permission checks need to happen during
 110 *	each system call not at open time.  The reason is that most of
 111 *	what we wish to check for permissions in /proc varies at runtime.
 112 *
 113 *	The classic example of a problem is opening file descriptors
 114 *	in /proc for a task before it execs a suid executable.
 115 */
 116
 117static u8 nlink_tid __ro_after_init;
 118static u8 nlink_tgid __ro_after_init;
 119
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 120struct pid_entry {
 121	const char *name;
 122	unsigned int len;
 123	umode_t mode;
 124	const struct inode_operations *iop;
 125	const struct file_operations *fop;
 126	union proc_op op;
 127};
 128
 129#define NOD(NAME, MODE, IOP, FOP, OP) {			\
 130	.name = (NAME),					\
 131	.len  = sizeof(NAME) - 1,			\
 132	.mode = MODE,					\
 133	.iop  = IOP,					\
 134	.fop  = FOP,					\
 135	.op   = OP,					\
 136}
 137
 138#define DIR(NAME, MODE, iops, fops)	\
 139	NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 140#define LNK(NAME, get_link)					\
 141	NOD(NAME, (S_IFLNK|S_IRWXUGO),				\
 142		&proc_pid_link_inode_operations, NULL,		\
 143		{ .proc_get_link = get_link } )
 144#define REG(NAME, MODE, fops)				\
 145	NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 146#define ONE(NAME, MODE, show)				\
 147	NOD(NAME, (S_IFREG|(MODE)),			\
 148		NULL, &proc_single_file_operations,	\
 149		{ .proc_show = show } )
 150#define ATTR(LSMID, NAME, MODE)				\
 151	NOD(NAME, (S_IFREG|(MODE)),			\
 152		NULL, &proc_pid_attr_operations,	\
 153		{ .lsmid = LSMID })
 154
 155/*
 156 * Count the number of hardlinks for the pid_entry table, excluding the .
 157 * and .. links.
 158 */
 159static unsigned int __init pid_entry_nlink(const struct pid_entry *entries,
 160	unsigned int n)
 161{
 162	unsigned int i;
 163	unsigned int count;
 164
 165	count = 2;
 166	for (i = 0; i < n; ++i) {
 167		if (S_ISDIR(entries[i].mode))
 168			++count;
 169	}
 170
 171	return count;
 172}
 173
 174static int get_task_root(struct task_struct *task, struct path *root)
 175{
 176	int result = -ENOENT;
 177
 178	task_lock(task);
 179	if (task->fs) {
 180		get_fs_root(task->fs, root);
 181		result = 0;
 182	}
 183	task_unlock(task);
 184	return result;
 185}
 186
 187static int proc_cwd_link(struct dentry *dentry, struct path *path)
 188{
 189	struct task_struct *task = get_proc_task(d_inode(dentry));
 190	int result = -ENOENT;
 191
 192	if (task) {
 193		task_lock(task);
 194		if (task->fs) {
 195			get_fs_pwd(task->fs, path);
 196			result = 0;
 197		}
 198		task_unlock(task);
 199		put_task_struct(task);
 200	}
 201	return result;
 202}
 203
 204static int proc_root_link(struct dentry *dentry, struct path *path)
 205{
 206	struct task_struct *task = get_proc_task(d_inode(dentry));
 207	int result = -ENOENT;
 208
 209	if (task) {
 210		result = get_task_root(task, path);
 211		put_task_struct(task);
 212	}
 213	return result;
 214}
 215
 216/*
 217 * If the user used setproctitle(), we just get the string from
 218 * user space at arg_start, and limit it to a maximum of one page.
 219 */
 220static ssize_t get_mm_proctitle(struct mm_struct *mm, char __user *buf,
 221				size_t count, unsigned long pos,
 222				unsigned long arg_start)
 223{
 224	char *page;
 225	int ret, got;
 226
 227	if (pos >= PAGE_SIZE)
 228		return 0;
 229
 230	page = (char *)__get_free_page(GFP_KERNEL);
 231	if (!page)
 232		return -ENOMEM;
 233
 234	ret = 0;
 235	got = access_remote_vm(mm, arg_start, page, PAGE_SIZE, FOLL_ANON);
 236	if (got > 0) {
 237		int len = strnlen(page, got);
 238
 239		/* Include the NUL character if it was found */
 240		if (len < got)
 241			len++;
 242
 243		if (len > pos) {
 244			len -= pos;
 245			if (len > count)
 246				len = count;
 247			len -= copy_to_user(buf, page+pos, len);
 248			if (!len)
 249				len = -EFAULT;
 250			ret = len;
 251		}
 252	}
 253	free_page((unsigned long)page);
 254	return ret;
 255}
 256
 257static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf,
 258			      size_t count, loff_t *ppos)
 259{
 260	unsigned long arg_start, arg_end, env_start, env_end;
 261	unsigned long pos, len;
 262	char *page, c;
 263
 264	/* Check if process spawned far enough to have cmdline. */
 265	if (!mm->env_end)
 266		return 0;
 267
 268	spin_lock(&mm->arg_lock);
 269	arg_start = mm->arg_start;
 270	arg_end = mm->arg_end;
 271	env_start = mm->env_start;
 272	env_end = mm->env_end;
 273	spin_unlock(&mm->arg_lock);
 274
 275	if (arg_start >= arg_end)
 276		return 0;
 277
 278	/*
 279	 * We allow setproctitle() to overwrite the argument
 280	 * strings, and overflow past the original end. But
 281	 * only when it overflows into the environment area.
 282	 */
 283	if (env_start != arg_end || env_end < env_start)
 284		env_start = env_end = arg_end;
 285	len = env_end - arg_start;
 286
 287	/* We're not going to care if "*ppos" has high bits set */
 288	pos = *ppos;
 289	if (pos >= len)
 290		return 0;
 291	if (count > len - pos)
 292		count = len - pos;
 293	if (!count)
 294		return 0;
 295
 296	/*
 297	 * Magical special case: if the argv[] end byte is not
 298	 * zero, the user has overwritten it with setproctitle(3).
 299	 *
 300	 * Possible future enhancement: do this only once when
 301	 * pos is 0, and set a flag in the 'struct file'.
 302	 */
 303	if (access_remote_vm(mm, arg_end-1, &c, 1, FOLL_ANON) == 1 && c)
 304		return get_mm_proctitle(mm, buf, count, pos, arg_start);
 305
 306	/*
 307	 * For the non-setproctitle() case we limit things strictly
 308	 * to the [arg_start, arg_end[ range.
 309	 */
 310	pos += arg_start;
 311	if (pos < arg_start || pos >= arg_end)
 312		return 0;
 313	if (count > arg_end - pos)
 314		count = arg_end - pos;
 315
 316	page = (char *)__get_free_page(GFP_KERNEL);
 317	if (!page)
 318		return -ENOMEM;
 319
 320	len = 0;
 321	while (count) {
 322		int got;
 323		size_t size = min_t(size_t, PAGE_SIZE, count);
 324
 325		got = access_remote_vm(mm, pos, page, size, FOLL_ANON);
 326		if (got <= 0)
 327			break;
 328		got -= copy_to_user(buf, page, got);
 329		if (unlikely(!got)) {
 330			if (!len)
 331				len = -EFAULT;
 332			break;
 333		}
 334		pos += got;
 335		buf += got;
 336		len += got;
 337		count -= got;
 338	}
 339
 340	free_page((unsigned long)page);
 341	return len;
 342}
 343
 344static ssize_t get_task_cmdline(struct task_struct *tsk, char __user *buf,
 345				size_t count, loff_t *pos)
 346{
 347	struct mm_struct *mm;
 348	ssize_t ret;
 349
 350	mm = get_task_mm(tsk);
 351	if (!mm)
 352		return 0;
 353
 354	ret = get_mm_cmdline(mm, buf, count, pos);
 355	mmput(mm);
 356	return ret;
 357}
 358
 359static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
 360				     size_t count, loff_t *pos)
 361{
 362	struct task_struct *tsk;
 363	ssize_t ret;
 364
 365	BUG_ON(*pos < 0);
 366
 367	tsk = get_proc_task(file_inode(file));
 368	if (!tsk)
 369		return -ESRCH;
 370	ret = get_task_cmdline(tsk, buf, count, pos);
 371	put_task_struct(tsk);
 372	if (ret > 0)
 373		*pos += ret;
 374	return ret;
 375}
 376
 377static const struct file_operations proc_pid_cmdline_ops = {
 378	.read	= proc_pid_cmdline_read,
 379	.llseek	= generic_file_llseek,
 380};
 381
 382#ifdef CONFIG_KALLSYMS
 383/*
 384 * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 385 * Returns the resolved symbol.  If that fails, simply return the address.
 386 */
 387static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 388			  struct pid *pid, struct task_struct *task)
 389{
 390	unsigned long wchan;
 391	char symname[KSYM_NAME_LEN];
 392
 393	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
 394		goto print0;
 395
 396	wchan = get_wchan(task);
 397	if (wchan && !lookup_symbol_name(wchan, symname)) {
 398		seq_puts(m, symname);
 399		return 0;
 400	}
 401
 402print0:
 403	seq_putc(m, '0');
 404	return 0;
 405}
 406#endif /* CONFIG_KALLSYMS */
 407
 408static int lock_trace(struct task_struct *task)
 409{
 410	int err = down_read_killable(&task->signal->exec_update_lock);
 411	if (err)
 412		return err;
 413	if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
 414		up_read(&task->signal->exec_update_lock);
 415		return -EPERM;
 416	}
 417	return 0;
 418}
 419
 420static void unlock_trace(struct task_struct *task)
 421{
 422	up_read(&task->signal->exec_update_lock);
 423}
 424
 425#ifdef CONFIG_STACKTRACE
 426
 427#define MAX_STACK_TRACE_DEPTH	64
 428
 429static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 430			  struct pid *pid, struct task_struct *task)
 431{
 432	unsigned long *entries;
 433	int err;
 434
 435	/*
 436	 * The ability to racily run the kernel stack unwinder on a running task
 437	 * and then observe the unwinder output is scary; while it is useful for
 438	 * debugging kernel issues, it can also allow an attacker to leak kernel
 439	 * stack contents.
 440	 * Doing this in a manner that is at least safe from races would require
 441	 * some work to ensure that the remote task can not be scheduled; and
 442	 * even then, this would still expose the unwinder as local attack
 443	 * surface.
 444	 * Therefore, this interface is restricted to root.
 445	 */
 446	if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
 447		return -EACCES;
 448
 449	entries = kmalloc_array(MAX_STACK_TRACE_DEPTH, sizeof(*entries),
 450				GFP_KERNEL);
 451	if (!entries)
 452		return -ENOMEM;
 453
 454	err = lock_trace(task);
 455	if (!err) {
 456		unsigned int i, nr_entries;
 457
 458		nr_entries = stack_trace_save_tsk(task, entries,
 459						  MAX_STACK_TRACE_DEPTH, 0);
 460
 461		for (i = 0; i < nr_entries; i++) {
 462			seq_printf(m, "[<0>] %pB\n", (void *)entries[i]);
 463		}
 464
 465		unlock_trace(task);
 466	}
 467	kfree(entries);
 468
 469	return err;
 470}
 471#endif
 472
 473#ifdef CONFIG_SCHED_INFO
 474/*
 475 * Provides /proc/PID/schedstat
 476 */
 477static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 478			      struct pid *pid, struct task_struct *task)
 479{
 480	if (unlikely(!sched_info_on()))
 481		seq_puts(m, "0 0 0\n");
 482	else
 483		seq_printf(m, "%llu %llu %lu\n",
 484		   (unsigned long long)task->se.sum_exec_runtime,
 485		   (unsigned long long)task->sched_info.run_delay,
 486		   task->sched_info.pcount);
 487
 488	return 0;
 489}
 490#endif
 491
 492#ifdef CONFIG_LATENCYTOP
 493static int lstats_show_proc(struct seq_file *m, void *v)
 494{
 495	int i;
 496	struct inode *inode = m->private;
 497	struct task_struct *task = get_proc_task(inode);
 498
 499	if (!task)
 500		return -ESRCH;
 501	seq_puts(m, "Latency Top version : v0.1\n");
 502	for (i = 0; i < LT_SAVECOUNT; i++) {
 503		struct latency_record *lr = &task->latency_record[i];
 504		if (lr->backtrace[0]) {
 505			int q;
 506			seq_printf(m, "%i %li %li",
 507				   lr->count, lr->time, lr->max);
 508			for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 509				unsigned long bt = lr->backtrace[q];
 510
 511				if (!bt)
 512					break;
 513				seq_printf(m, " %ps", (void *)bt);
 514			}
 515			seq_putc(m, '\n');
 516		}
 517
 518	}
 519	put_task_struct(task);
 520	return 0;
 521}
 522
 523static int lstats_open(struct inode *inode, struct file *file)
 524{
 525	return single_open(file, lstats_show_proc, inode);
 526}
 527
 528static ssize_t lstats_write(struct file *file, const char __user *buf,
 529			    size_t count, loff_t *offs)
 530{
 531	struct task_struct *task = get_proc_task(file_inode(file));
 532
 533	if (!task)
 534		return -ESRCH;
 535	clear_tsk_latency_tracing(task);
 536	put_task_struct(task);
 537
 538	return count;
 539}
 540
 541static const struct file_operations proc_lstats_operations = {
 542	.open		= lstats_open,
 543	.read		= seq_read,
 544	.write		= lstats_write,
 545	.llseek		= seq_lseek,
 546	.release	= single_release,
 547};
 548
 549#endif
 550
 551static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
 552			  struct pid *pid, struct task_struct *task)
 553{
 554	unsigned long totalpages = totalram_pages() + total_swap_pages;
 555	unsigned long points = 0;
 556	long badness;
 557
 558	badness = oom_badness(task, totalpages);
 559	/*
 560	 * Special case OOM_SCORE_ADJ_MIN for all others scale the
 561	 * badness value into [0, 2000] range which we have been
 562	 * exporting for a long time so userspace might depend on it.
 563	 */
 564	if (badness != LONG_MIN)
 565		points = (1000 + badness * 1000 / (long)totalpages) * 2 / 3;
 566
 567	seq_printf(m, "%lu\n", points);
 568
 569	return 0;
 570}
 571
 572struct limit_names {
 573	const char *name;
 574	const char *unit;
 575};
 576
 577static const struct limit_names lnames[RLIM_NLIMITS] = {
 578	[RLIMIT_CPU] = {"Max cpu time", "seconds"},
 579	[RLIMIT_FSIZE] = {"Max file size", "bytes"},
 580	[RLIMIT_DATA] = {"Max data size", "bytes"},
 581	[RLIMIT_STACK] = {"Max stack size", "bytes"},
 582	[RLIMIT_CORE] = {"Max core file size", "bytes"},
 583	[RLIMIT_RSS] = {"Max resident set", "bytes"},
 584	[RLIMIT_NPROC] = {"Max processes", "processes"},
 585	[RLIMIT_NOFILE] = {"Max open files", "files"},
 586	[RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 587	[RLIMIT_AS] = {"Max address space", "bytes"},
 588	[RLIMIT_LOCKS] = {"Max file locks", "locks"},
 589	[RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 590	[RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 591	[RLIMIT_NICE] = {"Max nice priority", NULL},
 592	[RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 593	[RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 594};
 595
 596/* Display limits for a process */
 597static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 598			   struct pid *pid, struct task_struct *task)
 599{
 600	unsigned int i;
 601	unsigned long flags;
 602
 603	struct rlimit rlim[RLIM_NLIMITS];
 604
 605	if (!lock_task_sighand(task, &flags))
 606		return 0;
 607	memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 608	unlock_task_sighand(task, &flags);
 609
 610	/*
 611	 * print the file header
 612	 */
 613	seq_puts(m, "Limit                     "
 614		"Soft Limit           "
 615		"Hard Limit           "
 616		"Units     \n");
 617
 618	for (i = 0; i < RLIM_NLIMITS; i++) {
 619		if (rlim[i].rlim_cur == RLIM_INFINITY)
 620			seq_printf(m, "%-25s %-20s ",
 621				   lnames[i].name, "unlimited");
 622		else
 623			seq_printf(m, "%-25s %-20lu ",
 624				   lnames[i].name, rlim[i].rlim_cur);
 625
 626		if (rlim[i].rlim_max == RLIM_INFINITY)
 627			seq_printf(m, "%-20s ", "unlimited");
 628		else
 629			seq_printf(m, "%-20lu ", rlim[i].rlim_max);
 630
 631		if (lnames[i].unit)
 632			seq_printf(m, "%-10s\n", lnames[i].unit);
 633		else
 634			seq_putc(m, '\n');
 635	}
 636
 637	return 0;
 638}
 639
 640#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 641static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 642			    struct pid *pid, struct task_struct *task)
 643{
 644	struct syscall_info info;
 645	u64 *args = &info.data.args[0];
 646	int res;
 647
 648	res = lock_trace(task);
 649	if (res)
 650		return res;
 651
 652	if (task_current_syscall(task, &info))
 653		seq_puts(m, "running\n");
 654	else if (info.data.nr < 0)
 655		seq_printf(m, "%d 0x%llx 0x%llx\n",
 656			   info.data.nr, info.sp, info.data.instruction_pointer);
 657	else
 658		seq_printf(m,
 659		       "%d 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx\n",
 660		       info.data.nr,
 661		       args[0], args[1], args[2], args[3], args[4], args[5],
 662		       info.sp, info.data.instruction_pointer);
 663	unlock_trace(task);
 664
 665	return 0;
 666}
 667#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 668
 669/************************************************************************/
 670/*                       Here the fs part begins                        */
 671/************************************************************************/
 672
 673/* permission checks */
 674static bool proc_fd_access_allowed(struct inode *inode)
 675{
 676	struct task_struct *task;
 677	bool allowed = false;
 678	/* Allow access to a task's file descriptors if it is us or we
 679	 * may use ptrace attach to the process and find out that
 680	 * information.
 681	 */
 682	task = get_proc_task(inode);
 683	if (task) {
 684		allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 685		put_task_struct(task);
 686	}
 687	return allowed;
 688}
 689
 690int proc_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 691		 struct iattr *attr)
 692{
 693	int error;
 694	struct inode *inode = d_inode(dentry);
 695
 696	if (attr->ia_valid & ATTR_MODE)
 697		return -EPERM;
 698
 699	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 700	if (error)
 701		return error;
 702
 703	setattr_copy(&nop_mnt_idmap, inode, attr);
 704	return 0;
 705}
 706
 707/*
 708 * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 709 * or euid/egid (for hide_pid_min=2)?
 710 */
 711static bool has_pid_permissions(struct proc_fs_info *fs_info,
 712				 struct task_struct *task,
 713				 enum proc_hidepid hide_pid_min)
 714{
 715	/*
 716	 * If 'hidpid' mount option is set force a ptrace check,
 717	 * we indicate that we are using a filesystem syscall
 718	 * by passing PTRACE_MODE_READ_FSCREDS
 719	 */
 720	if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE)
 721		return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 722
 723	if (fs_info->hide_pid < hide_pid_min)
 724		return true;
 725	if (in_group_p(fs_info->pid_gid))
 726		return true;
 727	return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 728}
 729
 730
 731static int proc_pid_permission(struct mnt_idmap *idmap,
 732			       struct inode *inode, int mask)
 733{
 734	struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
 735	struct task_struct *task;
 736	bool has_perms;
 737
 738	task = get_proc_task(inode);
 739	if (!task)
 740		return -ESRCH;
 741	has_perms = has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS);
 742	put_task_struct(task);
 743
 744	if (!has_perms) {
 745		if (fs_info->hide_pid == HIDEPID_INVISIBLE) {
 746			/*
 747			 * Let's make getdents(), stat(), and open()
 748			 * consistent with each other.  If a process
 749			 * may not stat() a file, it shouldn't be seen
 750			 * in procfs at all.
 751			 */
 752			return -ENOENT;
 753		}
 754
 755		return -EPERM;
 756	}
 757	return generic_permission(&nop_mnt_idmap, inode, mask);
 758}
 759
 760
 761
 762static const struct inode_operations proc_def_inode_operations = {
 763	.setattr	= proc_setattr,
 764};
 765
 766static int proc_single_show(struct seq_file *m, void *v)
 767{
 768	struct inode *inode = m->private;
 769	struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
 770	struct pid *pid = proc_pid(inode);
 771	struct task_struct *task;
 772	int ret;
 773
 774	task = get_pid_task(pid, PIDTYPE_PID);
 775	if (!task)
 776		return -ESRCH;
 777
 778	ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 779
 780	put_task_struct(task);
 781	return ret;
 782}
 783
 784static int proc_single_open(struct inode *inode, struct file *filp)
 785{
 786	return single_open(filp, proc_single_show, inode);
 787}
 788
 789static const struct file_operations proc_single_file_operations = {
 790	.open		= proc_single_open,
 791	.read		= seq_read,
 792	.llseek		= seq_lseek,
 793	.release	= single_release,
 794};
 795
 796
 797struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
 798{
 799	struct task_struct *task = get_proc_task(inode);
 800	struct mm_struct *mm = ERR_PTR(-ESRCH);
 801
 802	if (task) {
 803		mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
 804		put_task_struct(task);
 805
 806		if (!IS_ERR_OR_NULL(mm)) {
 807			/* ensure this mm_struct can't be freed */
 808			mmgrab(mm);
 809			/* but do not pin its memory */
 810			mmput(mm);
 811		}
 812	}
 
 
 
 813
 814	return mm;
 815}
 816
 817static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 818{
 819	struct mm_struct *mm = proc_mem_open(inode, mode);
 820
 821	if (IS_ERR(mm))
 822		return PTR_ERR(mm);
 823
 824	file->private_data = mm;
 825	return 0;
 826}
 827
 828static int mem_open(struct inode *inode, struct file *file)
 829{
 830	int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
 
 
 
 831
 832	/* OK to pass negative loff_t, we can catch out-of-range */
 833	file->f_mode |= FMODE_UNSIGNED_OFFSET;
 
 
 834
 835	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 836}
 837
 838static ssize_t mem_rw(struct file *file, char __user *buf,
 839			size_t count, loff_t *ppos, int write)
 840{
 841	struct mm_struct *mm = file->private_data;
 842	unsigned long addr = *ppos;
 843	ssize_t copied;
 844	char *page;
 845	unsigned int flags;
 846
 847	if (!mm)
 848		return 0;
 849
 850	page = (char *)__get_free_page(GFP_KERNEL);
 851	if (!page)
 852		return -ENOMEM;
 853
 854	copied = 0;
 855	if (!mmget_not_zero(mm))
 856		goto free;
 857
 858	flags = FOLL_FORCE | (write ? FOLL_WRITE : 0);
 
 
 859
 860	while (count > 0) {
 861		size_t this_len = min_t(size_t, count, PAGE_SIZE);
 862
 863		if (write && copy_from_user(page, buf, this_len)) {
 864			copied = -EFAULT;
 865			break;
 866		}
 867
 868		this_len = access_remote_vm(mm, addr, page, this_len, flags);
 869		if (!this_len) {
 870			if (!copied)
 871				copied = -EIO;
 872			break;
 873		}
 874
 875		if (!write && copy_to_user(buf, page, this_len)) {
 876			copied = -EFAULT;
 877			break;
 878		}
 879
 880		buf += this_len;
 881		addr += this_len;
 882		copied += this_len;
 883		count -= this_len;
 884	}
 885	*ppos = addr;
 886
 887	mmput(mm);
 888free:
 889	free_page((unsigned long) page);
 890	return copied;
 891}
 892
 893static ssize_t mem_read(struct file *file, char __user *buf,
 894			size_t count, loff_t *ppos)
 895{
 896	return mem_rw(file, buf, count, ppos, 0);
 897}
 898
 899static ssize_t mem_write(struct file *file, const char __user *buf,
 900			 size_t count, loff_t *ppos)
 901{
 902	return mem_rw(file, (char __user*)buf, count, ppos, 1);
 903}
 904
 905loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 906{
 907	switch (orig) {
 908	case 0:
 909		file->f_pos = offset;
 910		break;
 911	case 1:
 912		file->f_pos += offset;
 913		break;
 914	default:
 915		return -EINVAL;
 916	}
 917	force_successful_syscall_return();
 918	return file->f_pos;
 919}
 920
 921static int mem_release(struct inode *inode, struct file *file)
 922{
 923	struct mm_struct *mm = file->private_data;
 924	if (mm)
 925		mmdrop(mm);
 926	return 0;
 927}
 928
 929static const struct file_operations proc_mem_operations = {
 930	.llseek		= mem_lseek,
 931	.read		= mem_read,
 932	.write		= mem_write,
 933	.open		= mem_open,
 934	.release	= mem_release,
 
 935};
 936
 937static int environ_open(struct inode *inode, struct file *file)
 938{
 939	return __mem_open(inode, file, PTRACE_MODE_READ);
 940}
 941
 942static ssize_t environ_read(struct file *file, char __user *buf,
 943			size_t count, loff_t *ppos)
 944{
 945	char *page;
 946	unsigned long src = *ppos;
 947	int ret = 0;
 948	struct mm_struct *mm = file->private_data;
 949	unsigned long env_start, env_end;
 950
 951	/* Ensure the process spawned far enough to have an environment. */
 952	if (!mm || !mm->env_end)
 953		return 0;
 954
 955	page = (char *)__get_free_page(GFP_KERNEL);
 956	if (!page)
 957		return -ENOMEM;
 958
 959	ret = 0;
 960	if (!mmget_not_zero(mm))
 961		goto free;
 962
 963	spin_lock(&mm->arg_lock);
 964	env_start = mm->env_start;
 965	env_end = mm->env_end;
 966	spin_unlock(&mm->arg_lock);
 967
 968	while (count > 0) {
 969		size_t this_len, max_len;
 970		int retval;
 971
 972		if (src >= (env_end - env_start))
 973			break;
 974
 975		this_len = env_end - (env_start + src);
 976
 977		max_len = min_t(size_t, PAGE_SIZE, count);
 978		this_len = min(max_len, this_len);
 979
 980		retval = access_remote_vm(mm, (env_start + src), page, this_len, FOLL_ANON);
 981
 982		if (retval <= 0) {
 983			ret = retval;
 984			break;
 985		}
 986
 987		if (copy_to_user(buf, page, retval)) {
 988			ret = -EFAULT;
 989			break;
 990		}
 991
 992		ret += retval;
 993		src += retval;
 994		buf += retval;
 995		count -= retval;
 996	}
 997	*ppos = src;
 998	mmput(mm);
 999
1000free:
1001	free_page((unsigned long) page);
1002	return ret;
1003}
1004
1005static const struct file_operations proc_environ_operations = {
1006	.open		= environ_open,
1007	.read		= environ_read,
1008	.llseek		= generic_file_llseek,
1009	.release	= mem_release,
1010};
1011
1012static int auxv_open(struct inode *inode, struct file *file)
1013{
1014	return __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
1015}
1016
1017static ssize_t auxv_read(struct file *file, char __user *buf,
1018			size_t count, loff_t *ppos)
1019{
1020	struct mm_struct *mm = file->private_data;
1021	unsigned int nwords = 0;
1022
1023	if (!mm)
1024		return 0;
1025	do {
1026		nwords += 2;
1027	} while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
1028	return simple_read_from_buffer(buf, count, ppos, mm->saved_auxv,
1029				       nwords * sizeof(mm->saved_auxv[0]));
1030}
1031
1032static const struct file_operations proc_auxv_operations = {
1033	.open		= auxv_open,
1034	.read		= auxv_read,
1035	.llseek		= generic_file_llseek,
1036	.release	= mem_release,
1037};
1038
1039static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1040			    loff_t *ppos)
1041{
1042	struct task_struct *task = get_proc_task(file_inode(file));
1043	char buffer[PROC_NUMBUF];
1044	int oom_adj = OOM_ADJUST_MIN;
1045	size_t len;
1046
1047	if (!task)
1048		return -ESRCH;
1049	if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1050		oom_adj = OOM_ADJUST_MAX;
1051	else
1052		oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1053			  OOM_SCORE_ADJ_MAX;
1054	put_task_struct(task);
1055	if (oom_adj > OOM_ADJUST_MAX)
1056		oom_adj = OOM_ADJUST_MAX;
1057	len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1058	return simple_read_from_buffer(buf, count, ppos, buffer, len);
1059}
1060
1061static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1062{
1063	struct mm_struct *mm = NULL;
1064	struct task_struct *task;
1065	int err = 0;
1066
1067	task = get_proc_task(file_inode(file));
1068	if (!task)
1069		return -ESRCH;
1070
1071	mutex_lock(&oom_adj_mutex);
1072	if (legacy) {
1073		if (oom_adj < task->signal->oom_score_adj &&
1074				!capable(CAP_SYS_RESOURCE)) {
1075			err = -EACCES;
1076			goto err_unlock;
1077		}
1078		/*
1079		 * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1080		 * /proc/pid/oom_score_adj instead.
1081		 */
1082		pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1083			  current->comm, task_pid_nr(current), task_pid_nr(task),
1084			  task_pid_nr(task));
1085	} else {
1086		if ((short)oom_adj < task->signal->oom_score_adj_min &&
1087				!capable(CAP_SYS_RESOURCE)) {
1088			err = -EACCES;
1089			goto err_unlock;
1090		}
1091	}
1092
1093	/*
1094	 * Make sure we will check other processes sharing the mm if this is
1095	 * not vfrok which wants its own oom_score_adj.
1096	 * pin the mm so it doesn't go away and get reused after task_unlock
1097	 */
1098	if (!task->vfork_done) {
1099		struct task_struct *p = find_lock_task_mm(task);
1100
1101		if (p) {
1102			if (test_bit(MMF_MULTIPROCESS, &p->mm->flags)) {
1103				mm = p->mm;
1104				mmgrab(mm);
1105			}
1106			task_unlock(p);
1107		}
1108	}
1109
1110	task->signal->oom_score_adj = oom_adj;
1111	if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1112		task->signal->oom_score_adj_min = (short)oom_adj;
1113	trace_oom_score_adj_update(task);
1114
1115	if (mm) {
1116		struct task_struct *p;
1117
1118		rcu_read_lock();
1119		for_each_process(p) {
1120			if (same_thread_group(task, p))
1121				continue;
1122
1123			/* do not touch kernel threads or the global init */
1124			if (p->flags & PF_KTHREAD || is_global_init(p))
1125				continue;
1126
1127			task_lock(p);
1128			if (!p->vfork_done && process_shares_mm(p, mm)) {
1129				p->signal->oom_score_adj = oom_adj;
1130				if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1131					p->signal->oom_score_adj_min = (short)oom_adj;
1132			}
1133			task_unlock(p);
1134		}
1135		rcu_read_unlock();
1136		mmdrop(mm);
1137	}
1138err_unlock:
1139	mutex_unlock(&oom_adj_mutex);
1140	put_task_struct(task);
1141	return err;
1142}
1143
1144/*
1145 * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1146 * kernels.  The effective policy is defined by oom_score_adj, which has a
1147 * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1148 * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1149 * Processes that become oom disabled via oom_adj will still be oom disabled
1150 * with this implementation.
1151 *
1152 * oom_adj cannot be removed since existing userspace binaries use it.
1153 */
1154static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1155			     size_t count, loff_t *ppos)
1156{
1157	char buffer[PROC_NUMBUF] = {};
1158	int oom_adj;
1159	int err;
1160
1161	if (count > sizeof(buffer) - 1)
1162		count = sizeof(buffer) - 1;
1163	if (copy_from_user(buffer, buf, count)) {
1164		err = -EFAULT;
1165		goto out;
1166	}
1167
1168	err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1169	if (err)
1170		goto out;
1171	if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1172	     oom_adj != OOM_DISABLE) {
1173		err = -EINVAL;
1174		goto out;
1175	}
1176
1177	/*
1178	 * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1179	 * value is always attainable.
1180	 */
1181	if (oom_adj == OOM_ADJUST_MAX)
1182		oom_adj = OOM_SCORE_ADJ_MAX;
1183	else
1184		oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1185
1186	err = __set_oom_adj(file, oom_adj, true);
1187out:
1188	return err < 0 ? err : count;
1189}
1190
1191static const struct file_operations proc_oom_adj_operations = {
1192	.read		= oom_adj_read,
1193	.write		= oom_adj_write,
1194	.llseek		= generic_file_llseek,
1195};
1196
1197static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1198					size_t count, loff_t *ppos)
1199{
1200	struct task_struct *task = get_proc_task(file_inode(file));
1201	char buffer[PROC_NUMBUF];
1202	short oom_score_adj = OOM_SCORE_ADJ_MIN;
1203	size_t len;
1204
1205	if (!task)
1206		return -ESRCH;
1207	oom_score_adj = task->signal->oom_score_adj;
1208	put_task_struct(task);
1209	len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1210	return simple_read_from_buffer(buf, count, ppos, buffer, len);
1211}
1212
1213static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1214					size_t count, loff_t *ppos)
1215{
1216	char buffer[PROC_NUMBUF] = {};
1217	int oom_score_adj;
1218	int err;
1219
1220	if (count > sizeof(buffer) - 1)
1221		count = sizeof(buffer) - 1;
1222	if (copy_from_user(buffer, buf, count)) {
1223		err = -EFAULT;
1224		goto out;
1225	}
1226
1227	err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1228	if (err)
1229		goto out;
1230	if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1231			oom_score_adj > OOM_SCORE_ADJ_MAX) {
1232		err = -EINVAL;
1233		goto out;
1234	}
1235
1236	err = __set_oom_adj(file, oom_score_adj, false);
1237out:
1238	return err < 0 ? err : count;
1239}
1240
1241static const struct file_operations proc_oom_score_adj_operations = {
1242	.read		= oom_score_adj_read,
1243	.write		= oom_score_adj_write,
1244	.llseek		= default_llseek,
1245};
1246
1247#ifdef CONFIG_AUDIT
1248#define TMPBUFLEN 11
1249static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1250				  size_t count, loff_t *ppos)
1251{
1252	struct inode * inode = file_inode(file);
1253	struct task_struct *task = get_proc_task(inode);
1254	ssize_t length;
1255	char tmpbuf[TMPBUFLEN];
1256
1257	if (!task)
1258		return -ESRCH;
1259	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1260			   from_kuid(file->f_cred->user_ns,
1261				     audit_get_loginuid(task)));
1262	put_task_struct(task);
1263	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1264}
1265
1266static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1267				   size_t count, loff_t *ppos)
1268{
1269	struct inode * inode = file_inode(file);
1270	uid_t loginuid;
1271	kuid_t kloginuid;
1272	int rv;
1273
1274	/* Don't let kthreads write their own loginuid */
1275	if (current->flags & PF_KTHREAD)
1276		return -EPERM;
1277
1278	rcu_read_lock();
1279	if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1280		rcu_read_unlock();
1281		return -EPERM;
1282	}
1283	rcu_read_unlock();
1284
1285	if (*ppos != 0) {
1286		/* No partial writes. */
1287		return -EINVAL;
1288	}
1289
1290	rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1291	if (rv < 0)
1292		return rv;
1293
1294	/* is userspace tring to explicitly UNSET the loginuid? */
1295	if (loginuid == AUDIT_UID_UNSET) {
1296		kloginuid = INVALID_UID;
1297	} else {
1298		kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1299		if (!uid_valid(kloginuid))
1300			return -EINVAL;
1301	}
1302
1303	rv = audit_set_loginuid(kloginuid);
1304	if (rv < 0)
1305		return rv;
1306	return count;
1307}
1308
1309static const struct file_operations proc_loginuid_operations = {
1310	.read		= proc_loginuid_read,
1311	.write		= proc_loginuid_write,
1312	.llseek		= generic_file_llseek,
1313};
1314
1315static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1316				  size_t count, loff_t *ppos)
1317{
1318	struct inode * inode = file_inode(file);
1319	struct task_struct *task = get_proc_task(inode);
1320	ssize_t length;
1321	char tmpbuf[TMPBUFLEN];
1322
1323	if (!task)
1324		return -ESRCH;
1325	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1326				audit_get_sessionid(task));
1327	put_task_struct(task);
1328	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1329}
1330
1331static const struct file_operations proc_sessionid_operations = {
1332	.read		= proc_sessionid_read,
1333	.llseek		= generic_file_llseek,
1334};
1335#endif
1336
1337#ifdef CONFIG_FAULT_INJECTION
1338static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1339				      size_t count, loff_t *ppos)
1340{
1341	struct task_struct *task = get_proc_task(file_inode(file));
1342	char buffer[PROC_NUMBUF];
1343	size_t len;
1344	int make_it_fail;
1345
1346	if (!task)
1347		return -ESRCH;
1348	make_it_fail = task->make_it_fail;
1349	put_task_struct(task);
1350
1351	len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1352
1353	return simple_read_from_buffer(buf, count, ppos, buffer, len);
1354}
1355
1356static ssize_t proc_fault_inject_write(struct file * file,
1357			const char __user * buf, size_t count, loff_t *ppos)
1358{
1359	struct task_struct *task;
1360	char buffer[PROC_NUMBUF] = {};
1361	int make_it_fail;
1362	int rv;
1363
1364	if (!capable(CAP_SYS_RESOURCE))
1365		return -EPERM;
1366
1367	if (count > sizeof(buffer) - 1)
1368		count = sizeof(buffer) - 1;
1369	if (copy_from_user(buffer, buf, count))
1370		return -EFAULT;
1371	rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1372	if (rv < 0)
1373		return rv;
1374	if (make_it_fail < 0 || make_it_fail > 1)
1375		return -EINVAL;
1376
1377	task = get_proc_task(file_inode(file));
1378	if (!task)
1379		return -ESRCH;
1380	task->make_it_fail = make_it_fail;
1381	put_task_struct(task);
1382
1383	return count;
1384}
1385
1386static const struct file_operations proc_fault_inject_operations = {
1387	.read		= proc_fault_inject_read,
1388	.write		= proc_fault_inject_write,
1389	.llseek		= generic_file_llseek,
1390};
1391
1392static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
1393				   size_t count, loff_t *ppos)
1394{
1395	struct task_struct *task;
1396	int err;
1397	unsigned int n;
1398
1399	err = kstrtouint_from_user(buf, count, 0, &n);
1400	if (err)
1401		return err;
1402
1403	task = get_proc_task(file_inode(file));
1404	if (!task)
1405		return -ESRCH;
1406	task->fail_nth = n;
1407	put_task_struct(task);
1408
1409	return count;
1410}
1411
1412static ssize_t proc_fail_nth_read(struct file *file, char __user *buf,
1413				  size_t count, loff_t *ppos)
1414{
1415	struct task_struct *task;
1416	char numbuf[PROC_NUMBUF];
1417	ssize_t len;
1418
1419	task = get_proc_task(file_inode(file));
1420	if (!task)
1421		return -ESRCH;
1422	len = snprintf(numbuf, sizeof(numbuf), "%u\n", task->fail_nth);
1423	put_task_struct(task);
1424	return simple_read_from_buffer(buf, count, ppos, numbuf, len);
1425}
1426
1427static const struct file_operations proc_fail_nth_operations = {
1428	.read		= proc_fail_nth_read,
1429	.write		= proc_fail_nth_write,
1430};
1431#endif
1432
1433
1434#ifdef CONFIG_SCHED_DEBUG
1435/*
1436 * Print out various scheduling related per-task fields:
1437 */
1438static int sched_show(struct seq_file *m, void *v)
1439{
1440	struct inode *inode = m->private;
1441	struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
1442	struct task_struct *p;
1443
1444	p = get_proc_task(inode);
1445	if (!p)
1446		return -ESRCH;
1447	proc_sched_show_task(p, ns, m);
1448
1449	put_task_struct(p);
1450
1451	return 0;
1452}
1453
1454static ssize_t
1455sched_write(struct file *file, const char __user *buf,
1456	    size_t count, loff_t *offset)
1457{
1458	struct inode *inode = file_inode(file);
1459	struct task_struct *p;
1460
1461	p = get_proc_task(inode);
1462	if (!p)
1463		return -ESRCH;
1464	proc_sched_set_task(p);
1465
1466	put_task_struct(p);
1467
1468	return count;
1469}
1470
1471static int sched_open(struct inode *inode, struct file *filp)
1472{
1473	return single_open(filp, sched_show, inode);
1474}
1475
1476static const struct file_operations proc_pid_sched_operations = {
1477	.open		= sched_open,
1478	.read		= seq_read,
1479	.write		= sched_write,
1480	.llseek		= seq_lseek,
1481	.release	= single_release,
1482};
1483
1484#endif
1485
1486#ifdef CONFIG_SCHED_AUTOGROUP
1487/*
1488 * Print out autogroup related information:
1489 */
1490static int sched_autogroup_show(struct seq_file *m, void *v)
1491{
1492	struct inode *inode = m->private;
1493	struct task_struct *p;
1494
1495	p = get_proc_task(inode);
1496	if (!p)
1497		return -ESRCH;
1498	proc_sched_autogroup_show_task(p, m);
1499
1500	put_task_struct(p);
1501
1502	return 0;
1503}
1504
1505static ssize_t
1506sched_autogroup_write(struct file *file, const char __user *buf,
1507	    size_t count, loff_t *offset)
1508{
1509	struct inode *inode = file_inode(file);
1510	struct task_struct *p;
1511	char buffer[PROC_NUMBUF] = {};
1512	int nice;
1513	int err;
1514
1515	if (count > sizeof(buffer) - 1)
1516		count = sizeof(buffer) - 1;
1517	if (copy_from_user(buffer, buf, count))
1518		return -EFAULT;
1519
1520	err = kstrtoint(strstrip(buffer), 0, &nice);
1521	if (err < 0)
1522		return err;
1523
1524	p = get_proc_task(inode);
1525	if (!p)
1526		return -ESRCH;
1527
1528	err = proc_sched_autogroup_set_nice(p, nice);
1529	if (err)
1530		count = err;
1531
1532	put_task_struct(p);
1533
1534	return count;
1535}
1536
1537static int sched_autogroup_open(struct inode *inode, struct file *filp)
1538{
1539	int ret;
1540
1541	ret = single_open(filp, sched_autogroup_show, NULL);
1542	if (!ret) {
1543		struct seq_file *m = filp->private_data;
1544
1545		m->private = inode;
1546	}
1547	return ret;
1548}
1549
1550static const struct file_operations proc_pid_sched_autogroup_operations = {
1551	.open		= sched_autogroup_open,
1552	.read		= seq_read,
1553	.write		= sched_autogroup_write,
1554	.llseek		= seq_lseek,
1555	.release	= single_release,
1556};
1557
1558#endif /* CONFIG_SCHED_AUTOGROUP */
1559
1560#ifdef CONFIG_TIME_NS
1561static int timens_offsets_show(struct seq_file *m, void *v)
1562{
1563	struct task_struct *p;
1564
1565	p = get_proc_task(file_inode(m->file));
1566	if (!p)
1567		return -ESRCH;
1568	proc_timens_show_offsets(p, m);
1569
1570	put_task_struct(p);
1571
1572	return 0;
1573}
1574
1575static ssize_t timens_offsets_write(struct file *file, const char __user *buf,
1576				    size_t count, loff_t *ppos)
1577{
1578	struct inode *inode = file_inode(file);
1579	struct proc_timens_offset offsets[2];
1580	char *kbuf = NULL, *pos, *next_line;
1581	struct task_struct *p;
1582	int ret, noffsets;
1583
1584	/* Only allow < page size writes at the beginning of the file */
1585	if ((*ppos != 0) || (count >= PAGE_SIZE))
1586		return -EINVAL;
1587
1588	/* Slurp in the user data */
1589	kbuf = memdup_user_nul(buf, count);
1590	if (IS_ERR(kbuf))
1591		return PTR_ERR(kbuf);
1592
1593	/* Parse the user data */
1594	ret = -EINVAL;
1595	noffsets = 0;
1596	for (pos = kbuf; pos; pos = next_line) {
1597		struct proc_timens_offset *off = &offsets[noffsets];
1598		char clock[10];
1599		int err;
1600
1601		/* Find the end of line and ensure we don't look past it */
1602		next_line = strchr(pos, '\n');
1603		if (next_line) {
1604			*next_line = '\0';
1605			next_line++;
1606			if (*next_line == '\0')
1607				next_line = NULL;
1608		}
1609
1610		err = sscanf(pos, "%9s %lld %lu", clock,
1611				&off->val.tv_sec, &off->val.tv_nsec);
1612		if (err != 3 || off->val.tv_nsec >= NSEC_PER_SEC)
1613			goto out;
1614
1615		clock[sizeof(clock) - 1] = 0;
1616		if (strcmp(clock, "monotonic") == 0 ||
1617		    strcmp(clock, __stringify(CLOCK_MONOTONIC)) == 0)
1618			off->clockid = CLOCK_MONOTONIC;
1619		else if (strcmp(clock, "boottime") == 0 ||
1620			 strcmp(clock, __stringify(CLOCK_BOOTTIME)) == 0)
1621			off->clockid = CLOCK_BOOTTIME;
1622		else
1623			goto out;
1624
1625		noffsets++;
1626		if (noffsets == ARRAY_SIZE(offsets)) {
1627			if (next_line)
1628				count = next_line - kbuf;
1629			break;
1630		}
1631	}
1632
1633	ret = -ESRCH;
1634	p = get_proc_task(inode);
1635	if (!p)
1636		goto out;
1637	ret = proc_timens_set_offset(file, p, offsets, noffsets);
1638	put_task_struct(p);
1639	if (ret)
1640		goto out;
1641
1642	ret = count;
1643out:
1644	kfree(kbuf);
1645	return ret;
1646}
1647
1648static int timens_offsets_open(struct inode *inode, struct file *filp)
1649{
1650	return single_open(filp, timens_offsets_show, inode);
1651}
1652
1653static const struct file_operations proc_timens_offsets_operations = {
1654	.open		= timens_offsets_open,
1655	.read		= seq_read,
1656	.write		= timens_offsets_write,
1657	.llseek		= seq_lseek,
1658	.release	= single_release,
1659};
1660#endif /* CONFIG_TIME_NS */
1661
1662static ssize_t comm_write(struct file *file, const char __user *buf,
1663				size_t count, loff_t *offset)
1664{
1665	struct inode *inode = file_inode(file);
1666	struct task_struct *p;
1667	char buffer[TASK_COMM_LEN] = {};
1668	const size_t maxlen = sizeof(buffer) - 1;
1669
1670	if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1671		return -EFAULT;
1672
1673	p = get_proc_task(inode);
1674	if (!p)
1675		return -ESRCH;
1676
1677	if (same_thread_group(current, p)) {
1678		set_task_comm(p, buffer);
1679		proc_comm_connector(p);
1680	}
1681	else
1682		count = -EINVAL;
1683
1684	put_task_struct(p);
1685
1686	return count;
1687}
1688
1689static int comm_show(struct seq_file *m, void *v)
1690{
1691	struct inode *inode = m->private;
1692	struct task_struct *p;
1693
1694	p = get_proc_task(inode);
1695	if (!p)
1696		return -ESRCH;
1697
1698	proc_task_name(m, p, false);
1699	seq_putc(m, '\n');
1700
1701	put_task_struct(p);
1702
1703	return 0;
1704}
1705
1706static int comm_open(struct inode *inode, struct file *filp)
1707{
1708	return single_open(filp, comm_show, inode);
1709}
1710
1711static const struct file_operations proc_pid_set_comm_operations = {
1712	.open		= comm_open,
1713	.read		= seq_read,
1714	.write		= comm_write,
1715	.llseek		= seq_lseek,
1716	.release	= single_release,
1717};
1718
1719static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1720{
1721	struct task_struct *task;
1722	struct file *exe_file;
1723
1724	task = get_proc_task(d_inode(dentry));
1725	if (!task)
1726		return -ENOENT;
1727	exe_file = get_task_exe_file(task);
1728	put_task_struct(task);
1729	if (exe_file) {
1730		*exe_path = exe_file->f_path;
1731		path_get(&exe_file->f_path);
1732		fput(exe_file);
1733		return 0;
1734	} else
1735		return -ENOENT;
1736}
1737
1738static const char *proc_pid_get_link(struct dentry *dentry,
1739				     struct inode *inode,
1740				     struct delayed_call *done)
1741{
1742	struct path path;
1743	int error = -EACCES;
1744
1745	if (!dentry)
1746		return ERR_PTR(-ECHILD);
1747
1748	/* Are we allowed to snoop on the tasks file descriptors? */
1749	if (!proc_fd_access_allowed(inode))
1750		goto out;
1751
1752	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1753	if (error)
1754		goto out;
1755
1756	error = nd_jump_link(&path);
1757out:
1758	return ERR_PTR(error);
1759}
1760
1761static int do_proc_readlink(const struct path *path, char __user *buffer, int buflen)
1762{
1763	char *tmp = kmalloc(PATH_MAX, GFP_KERNEL);
1764	char *pathname;
1765	int len;
1766
1767	if (!tmp)
1768		return -ENOMEM;
1769
1770	pathname = d_path(path, tmp, PATH_MAX);
1771	len = PTR_ERR(pathname);
1772	if (IS_ERR(pathname))
1773		goto out;
1774	len = tmp + PATH_MAX - 1 - pathname;
1775
1776	if (len > buflen)
1777		len = buflen;
1778	if (copy_to_user(buffer, pathname, len))
1779		len = -EFAULT;
1780 out:
1781	kfree(tmp);
1782	return len;
1783}
1784
1785static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1786{
1787	int error = -EACCES;
1788	struct inode *inode = d_inode(dentry);
1789	struct path path;
1790
1791	/* Are we allowed to snoop on the tasks file descriptors? */
1792	if (!proc_fd_access_allowed(inode))
1793		goto out;
1794
1795	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1796	if (error)
1797		goto out;
1798
1799	error = do_proc_readlink(&path, buffer, buflen);
1800	path_put(&path);
1801out:
1802	return error;
1803}
1804
1805const struct inode_operations proc_pid_link_inode_operations = {
1806	.readlink	= proc_pid_readlink,
1807	.get_link	= proc_pid_get_link,
1808	.setattr	= proc_setattr,
1809};
1810
1811
1812/* building an inode */
1813
1814void task_dump_owner(struct task_struct *task, umode_t mode,
1815		     kuid_t *ruid, kgid_t *rgid)
1816{
1817	/* Depending on the state of dumpable compute who should own a
1818	 * proc file for a task.
1819	 */
1820	const struct cred *cred;
1821	kuid_t uid;
1822	kgid_t gid;
1823
1824	if (unlikely(task->flags & PF_KTHREAD)) {
1825		*ruid = GLOBAL_ROOT_UID;
1826		*rgid = GLOBAL_ROOT_GID;
1827		return;
1828	}
1829
1830	/* Default to the tasks effective ownership */
1831	rcu_read_lock();
1832	cred = __task_cred(task);
1833	uid = cred->euid;
1834	gid = cred->egid;
1835	rcu_read_unlock();
1836
1837	/*
1838	 * Before the /proc/pid/status file was created the only way to read
1839	 * the effective uid of a /process was to stat /proc/pid.  Reading
1840	 * /proc/pid/status is slow enough that procps and other packages
1841	 * kept stating /proc/pid.  To keep the rules in /proc simple I have
1842	 * made this apply to all per process world readable and executable
1843	 * directories.
1844	 */
1845	if (mode != (S_IFDIR|S_IRUGO|S_IXUGO)) {
1846		struct mm_struct *mm;
1847		task_lock(task);
1848		mm = task->mm;
1849		/* Make non-dumpable tasks owned by some root */
1850		if (mm) {
1851			if (get_dumpable(mm) != SUID_DUMP_USER) {
1852				struct user_namespace *user_ns = mm->user_ns;
1853
1854				uid = make_kuid(user_ns, 0);
1855				if (!uid_valid(uid))
1856					uid = GLOBAL_ROOT_UID;
1857
1858				gid = make_kgid(user_ns, 0);
1859				if (!gid_valid(gid))
1860					gid = GLOBAL_ROOT_GID;
1861			}
1862		} else {
1863			uid = GLOBAL_ROOT_UID;
1864			gid = GLOBAL_ROOT_GID;
1865		}
1866		task_unlock(task);
1867	}
1868	*ruid = uid;
1869	*rgid = gid;
1870}
1871
1872void proc_pid_evict_inode(struct proc_inode *ei)
1873{
1874	struct pid *pid = ei->pid;
1875
1876	if (S_ISDIR(ei->vfs_inode.i_mode)) {
1877		spin_lock(&pid->lock);
1878		hlist_del_init_rcu(&ei->sibling_inodes);
1879		spin_unlock(&pid->lock);
1880	}
1881}
1882
1883struct inode *proc_pid_make_inode(struct super_block *sb,
1884				  struct task_struct *task, umode_t mode)
1885{
1886	struct inode * inode;
1887	struct proc_inode *ei;
1888	struct pid *pid;
1889
1890	/* We need a new inode */
1891
1892	inode = new_inode(sb);
1893	if (!inode)
1894		goto out;
1895
1896	/* Common stuff */
1897	ei = PROC_I(inode);
1898	inode->i_mode = mode;
1899	inode->i_ino = get_next_ino();
1900	simple_inode_init_ts(inode);
1901	inode->i_op = &proc_def_inode_operations;
1902
1903	/*
1904	 * grab the reference to task.
1905	 */
1906	pid = get_task_pid(task, PIDTYPE_PID);
1907	if (!pid)
1908		goto out_unlock;
1909
1910	/* Let the pid remember us for quick removal */
1911	ei->pid = pid;
1912
1913	task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1914	security_task_to_inode(task, inode);
1915
1916out:
1917	return inode;
1918
1919out_unlock:
1920	iput(inode);
1921	return NULL;
1922}
1923
1924/*
1925 * Generating an inode and adding it into @pid->inodes, so that task will
1926 * invalidate inode's dentry before being released.
1927 *
1928 * This helper is used for creating dir-type entries under '/proc' and
1929 * '/proc/<tgid>/task'. Other entries(eg. fd, stat) under '/proc/<tgid>'
1930 * can be released by invalidating '/proc/<tgid>' dentry.
1931 * In theory, dentries under '/proc/<tgid>/task' can also be released by
1932 * invalidating '/proc/<tgid>' dentry, we reserve it to handle single
1933 * thread exiting situation: Any one of threads should invalidate its
1934 * '/proc/<tgid>/task/<pid>' dentry before released.
1935 */
1936static struct inode *proc_pid_make_base_inode(struct super_block *sb,
1937				struct task_struct *task, umode_t mode)
1938{
1939	struct inode *inode;
1940	struct proc_inode *ei;
1941	struct pid *pid;
1942
1943	inode = proc_pid_make_inode(sb, task, mode);
1944	if (!inode)
1945		return NULL;
1946
1947	/* Let proc_flush_pid find this directory inode */
1948	ei = PROC_I(inode);
1949	pid = ei->pid;
1950	spin_lock(&pid->lock);
1951	hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes);
1952	spin_unlock(&pid->lock);
1953
1954	return inode;
1955}
1956
1957int pid_getattr(struct mnt_idmap *idmap, const struct path *path,
1958		struct kstat *stat, u32 request_mask, unsigned int query_flags)
1959{
1960	struct inode *inode = d_inode(path->dentry);
1961	struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
1962	struct task_struct *task;
1963
1964	generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
1965
1966	stat->uid = GLOBAL_ROOT_UID;
1967	stat->gid = GLOBAL_ROOT_GID;
1968	rcu_read_lock();
1969	task = pid_task(proc_pid(inode), PIDTYPE_PID);
1970	if (task) {
1971		if (!has_pid_permissions(fs_info, task, HIDEPID_INVISIBLE)) {
1972			rcu_read_unlock();
1973			/*
1974			 * This doesn't prevent learning whether PID exists,
1975			 * it only makes getattr() consistent with readdir().
1976			 */
1977			return -ENOENT;
1978		}
1979		task_dump_owner(task, inode->i_mode, &stat->uid, &stat->gid);
1980	}
1981	rcu_read_unlock();
1982	return 0;
1983}
1984
1985/* dentry stuff */
1986
1987/*
1988 * Set <pid>/... inode ownership (can change due to setuid(), etc.)
1989 */
1990void pid_update_inode(struct task_struct *task, struct inode *inode)
1991{
1992	task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid);
1993
1994	inode->i_mode &= ~(S_ISUID | S_ISGID);
1995	security_task_to_inode(task, inode);
1996}
1997
1998/*
1999 * Rewrite the inode's ownerships here because the owning task may have
2000 * performed a setuid(), etc.
2001 *
2002 */
2003static int pid_revalidate(struct dentry *dentry, unsigned int flags)
2004{
2005	struct inode *inode;
2006	struct task_struct *task;
2007	int ret = 0;
2008
2009	rcu_read_lock();
2010	inode = d_inode_rcu(dentry);
2011	if (!inode)
2012		goto out;
2013	task = pid_task(proc_pid(inode), PIDTYPE_PID);
2014
2015	if (task) {
2016		pid_update_inode(task, inode);
2017		ret = 1;
2018	}
2019out:
2020	rcu_read_unlock();
2021	return ret;
2022}
2023
2024static inline bool proc_inode_is_dead(struct inode *inode)
2025{
2026	return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
2027}
2028
2029int pid_delete_dentry(const struct dentry *dentry)
2030{
2031	/* Is the task we represent dead?
2032	 * If so, then don't put the dentry on the lru list,
2033	 * kill it immediately.
2034	 */
2035	return proc_inode_is_dead(d_inode(dentry));
2036}
2037
2038const struct dentry_operations pid_dentry_operations =
2039{
2040	.d_revalidate	= pid_revalidate,
2041	.d_delete	= pid_delete_dentry,
2042};
2043
2044/* Lookups */
2045
2046/*
2047 * Fill a directory entry.
2048 *
2049 * If possible create the dcache entry and derive our inode number and
2050 * file type from dcache entry.
2051 *
2052 * Since all of the proc inode numbers are dynamically generated, the inode
2053 * numbers do not exist until the inode is cache.  This means creating
2054 * the dcache entry in readdir is necessary to keep the inode numbers
2055 * reported by readdir in sync with the inode numbers reported
2056 * by stat.
2057 */
2058bool proc_fill_cache(struct file *file, struct dir_context *ctx,
2059	const char *name, unsigned int len,
2060	instantiate_t instantiate, struct task_struct *task, const void *ptr)
2061{
2062	struct dentry *child, *dir = file->f_path.dentry;
2063	struct qstr qname = QSTR_INIT(name, len);
2064	struct inode *inode;
2065	unsigned type = DT_UNKNOWN;
2066	ino_t ino = 1;
2067
2068	child = d_hash_and_lookup(dir, &qname);
2069	if (!child) {
2070		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
2071		child = d_alloc_parallel(dir, &qname, &wq);
2072		if (IS_ERR(child))
2073			goto end_instantiate;
2074		if (d_in_lookup(child)) {
2075			struct dentry *res;
2076			res = instantiate(child, task, ptr);
2077			d_lookup_done(child);
2078			if (unlikely(res)) {
2079				dput(child);
2080				child = res;
2081				if (IS_ERR(child))
2082					goto end_instantiate;
2083			}
2084		}
2085	}
2086	inode = d_inode(child);
2087	ino = inode->i_ino;
2088	type = inode->i_mode >> 12;
2089	dput(child);
2090end_instantiate:
2091	return dir_emit(ctx, name, len, ino, type);
2092}
2093
2094/*
2095 * dname_to_vma_addr - maps a dentry name into two unsigned longs
2096 * which represent vma start and end addresses.
2097 */
2098static int dname_to_vma_addr(struct dentry *dentry,
2099			     unsigned long *start, unsigned long *end)
2100{
2101	const char *str = dentry->d_name.name;
2102	unsigned long long sval, eval;
2103	unsigned int len;
2104
2105	if (str[0] == '0' && str[1] != '-')
2106		return -EINVAL;
2107	len = _parse_integer(str, 16, &sval);
2108	if (len & KSTRTOX_OVERFLOW)
2109		return -EINVAL;
2110	if (sval != (unsigned long)sval)
2111		return -EINVAL;
2112	str += len;
2113
2114	if (*str != '-')
2115		return -EINVAL;
2116	str++;
2117
2118	if (str[0] == '0' && str[1])
2119		return -EINVAL;
2120	len = _parse_integer(str, 16, &eval);
2121	if (len & KSTRTOX_OVERFLOW)
2122		return -EINVAL;
2123	if (eval != (unsigned long)eval)
2124		return -EINVAL;
2125	str += len;
2126
2127	if (*str != '\0')
2128		return -EINVAL;
2129
2130	*start = sval;
2131	*end = eval;
2132
2133	return 0;
2134}
2135
2136static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
2137{
2138	unsigned long vm_start, vm_end;
2139	bool exact_vma_exists = false;
2140	struct mm_struct *mm = NULL;
2141	struct task_struct *task;
2142	struct inode *inode;
2143	int status = 0;
2144
2145	if (flags & LOOKUP_RCU)
2146		return -ECHILD;
2147
2148	inode = d_inode(dentry);
2149	task = get_proc_task(inode);
2150	if (!task)
2151		goto out_notask;
2152
2153	mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
2154	if (IS_ERR_OR_NULL(mm))
2155		goto out;
2156
2157	if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
2158		status = mmap_read_lock_killable(mm);
2159		if (!status) {
2160			exact_vma_exists = !!find_exact_vma(mm, vm_start,
2161							    vm_end);
2162			mmap_read_unlock(mm);
2163		}
2164	}
2165
2166	mmput(mm);
2167
2168	if (exact_vma_exists) {
2169		task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
2170
2171		security_task_to_inode(task, inode);
2172		status = 1;
2173	}
2174
2175out:
2176	put_task_struct(task);
2177
2178out_notask:
2179	return status;
2180}
2181
2182static const struct dentry_operations tid_map_files_dentry_operations = {
2183	.d_revalidate	= map_files_d_revalidate,
2184	.d_delete	= pid_delete_dentry,
2185};
2186
2187static int map_files_get_link(struct dentry *dentry, struct path *path)
2188{
2189	unsigned long vm_start, vm_end;
2190	struct vm_area_struct *vma;
2191	struct task_struct *task;
2192	struct mm_struct *mm;
2193	int rc;
2194
2195	rc = -ENOENT;
2196	task = get_proc_task(d_inode(dentry));
2197	if (!task)
2198		goto out;
2199
2200	mm = get_task_mm(task);
2201	put_task_struct(task);
2202	if (!mm)
2203		goto out;
2204
2205	rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
2206	if (rc)
2207		goto out_mmput;
2208
2209	rc = mmap_read_lock_killable(mm);
2210	if (rc)
2211		goto out_mmput;
2212
2213	rc = -ENOENT;
2214	vma = find_exact_vma(mm, vm_start, vm_end);
2215	if (vma && vma->vm_file) {
2216		*path = *file_user_path(vma->vm_file);
2217		path_get(path);
2218		rc = 0;
2219	}
2220	mmap_read_unlock(mm);
2221
2222out_mmput:
2223	mmput(mm);
2224out:
2225	return rc;
2226}
2227
2228struct map_files_info {
2229	unsigned long	start;
2230	unsigned long	end;
2231	fmode_t		mode;
2232};
2233
2234/*
2235 * Only allow CAP_SYS_ADMIN and CAP_CHECKPOINT_RESTORE to follow the links, due
2236 * to concerns about how the symlinks may be used to bypass permissions on
2237 * ancestor directories in the path to the file in question.
2238 */
2239static const char *
2240proc_map_files_get_link(struct dentry *dentry,
2241			struct inode *inode,
2242		        struct delayed_call *done)
2243{
2244	if (!checkpoint_restore_ns_capable(&init_user_ns))
2245		return ERR_PTR(-EPERM);
2246
2247	return proc_pid_get_link(dentry, inode, done);
2248}
2249
2250/*
2251 * Identical to proc_pid_link_inode_operations except for get_link()
2252 */
2253static const struct inode_operations proc_map_files_link_inode_operations = {
2254	.readlink	= proc_pid_readlink,
2255	.get_link	= proc_map_files_get_link,
2256	.setattr	= proc_setattr,
2257};
2258
2259static struct dentry *
2260proc_map_files_instantiate(struct dentry *dentry,
2261			   struct task_struct *task, const void *ptr)
2262{
2263	fmode_t mode = (fmode_t)(unsigned long)ptr;
2264	struct proc_inode *ei;
2265	struct inode *inode;
2266
2267	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK |
2268				    ((mode & FMODE_READ ) ? S_IRUSR : 0) |
2269				    ((mode & FMODE_WRITE) ? S_IWUSR : 0));
2270	if (!inode)
2271		return ERR_PTR(-ENOENT);
2272
2273	ei = PROC_I(inode);
2274	ei->op.proc_get_link = map_files_get_link;
2275
2276	inode->i_op = &proc_map_files_link_inode_operations;
2277	inode->i_size = 64;
2278
2279	d_set_d_op(dentry, &tid_map_files_dentry_operations);
2280	return d_splice_alias(inode, dentry);
2281}
2282
2283static struct dentry *proc_map_files_lookup(struct inode *dir,
2284		struct dentry *dentry, unsigned int flags)
2285{
2286	unsigned long vm_start, vm_end;
2287	struct vm_area_struct *vma;
2288	struct task_struct *task;
2289	struct dentry *result;
2290	struct mm_struct *mm;
2291
2292	result = ERR_PTR(-ENOENT);
2293	task = get_proc_task(dir);
2294	if (!task)
2295		goto out;
2296
2297	result = ERR_PTR(-EACCES);
2298	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2299		goto out_put_task;
2300
2301	result = ERR_PTR(-ENOENT);
2302	if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2303		goto out_put_task;
2304
2305	mm = get_task_mm(task);
2306	if (!mm)
2307		goto out_put_task;
2308
2309	result = ERR_PTR(-EINTR);
2310	if (mmap_read_lock_killable(mm))
2311		goto out_put_mm;
2312
2313	result = ERR_PTR(-ENOENT);
2314	vma = find_exact_vma(mm, vm_start, vm_end);
2315	if (!vma)
2316		goto out_no_vma;
2317
2318	if (vma->vm_file)
2319		result = proc_map_files_instantiate(dentry, task,
2320				(void *)(unsigned long)vma->vm_file->f_mode);
2321
2322out_no_vma:
2323	mmap_read_unlock(mm);
2324out_put_mm:
2325	mmput(mm);
2326out_put_task:
2327	put_task_struct(task);
2328out:
2329	return result;
2330}
2331
2332static const struct inode_operations proc_map_files_inode_operations = {
2333	.lookup		= proc_map_files_lookup,
2334	.permission	= proc_fd_permission,
2335	.setattr	= proc_setattr,
2336};
2337
2338static int
2339proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2340{
2341	struct vm_area_struct *vma;
2342	struct task_struct *task;
2343	struct mm_struct *mm;
2344	unsigned long nr_files, pos, i;
2345	GENRADIX(struct map_files_info) fa;
2346	struct map_files_info *p;
2347	int ret;
2348	struct vma_iterator vmi;
2349
2350	genradix_init(&fa);
2351
2352	ret = -ENOENT;
2353	task = get_proc_task(file_inode(file));
2354	if (!task)
2355		goto out;
2356
2357	ret = -EACCES;
2358	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2359		goto out_put_task;
2360
2361	ret = 0;
2362	if (!dir_emit_dots(file, ctx))
2363		goto out_put_task;
2364
2365	mm = get_task_mm(task);
2366	if (!mm)
2367		goto out_put_task;
2368
2369	ret = mmap_read_lock_killable(mm);
2370	if (ret) {
2371		mmput(mm);
2372		goto out_put_task;
2373	}
2374
2375	nr_files = 0;
2376
2377	/*
2378	 * We need two passes here:
2379	 *
2380	 *  1) Collect vmas of mapped files with mmap_lock taken
2381	 *  2) Release mmap_lock and instantiate entries
2382	 *
2383	 * otherwise we get lockdep complained, since filldir()
2384	 * routine might require mmap_lock taken in might_fault().
2385	 */
2386
2387	pos = 2;
2388	vma_iter_init(&vmi, mm, 0);
2389	for_each_vma(vmi, vma) {
2390		if (!vma->vm_file)
2391			continue;
2392		if (++pos <= ctx->pos)
2393			continue;
2394
2395		p = genradix_ptr_alloc(&fa, nr_files++, GFP_KERNEL);
2396		if (!p) {
2397			ret = -ENOMEM;
2398			mmap_read_unlock(mm);
2399			mmput(mm);
2400			goto out_put_task;
2401		}
2402
2403		p->start = vma->vm_start;
2404		p->end = vma->vm_end;
2405		p->mode = vma->vm_file->f_mode;
2406	}
2407	mmap_read_unlock(mm);
2408	mmput(mm);
2409
2410	for (i = 0; i < nr_files; i++) {
2411		char buf[4 * sizeof(long) + 2];	/* max: %lx-%lx\0 */
2412		unsigned int len;
2413
2414		p = genradix_ptr(&fa, i);
2415		len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);
2416		if (!proc_fill_cache(file, ctx,
2417				      buf, len,
2418				      proc_map_files_instantiate,
2419				      task,
2420				      (void *)(unsigned long)p->mode))
2421			break;
2422		ctx->pos++;
2423	}
2424
2425out_put_task:
2426	put_task_struct(task);
2427out:
2428	genradix_free(&fa);
2429	return ret;
2430}
2431
2432static const struct file_operations proc_map_files_operations = {
2433	.read		= generic_read_dir,
2434	.iterate_shared	= proc_map_files_readdir,
2435	.llseek		= generic_file_llseek,
2436};
2437
2438#if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
2439struct timers_private {
2440	struct pid *pid;
2441	struct task_struct *task;
2442	struct sighand_struct *sighand;
2443	struct pid_namespace *ns;
2444	unsigned long flags;
2445};
2446
2447static void *timers_start(struct seq_file *m, loff_t *pos)
2448{
2449	struct timers_private *tp = m->private;
2450
2451	tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2452	if (!tp->task)
2453		return ERR_PTR(-ESRCH);
2454
2455	tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2456	if (!tp->sighand)
2457		return ERR_PTR(-ESRCH);
2458
2459	return seq_list_start(&tp->task->signal->posix_timers, *pos);
2460}
2461
2462static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2463{
2464	struct timers_private *tp = m->private;
2465	return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2466}
2467
2468static void timers_stop(struct seq_file *m, void *v)
2469{
2470	struct timers_private *tp = m->private;
2471
2472	if (tp->sighand) {
2473		unlock_task_sighand(tp->task, &tp->flags);
2474		tp->sighand = NULL;
2475	}
2476
2477	if (tp->task) {
2478		put_task_struct(tp->task);
2479		tp->task = NULL;
2480	}
2481}
2482
2483static int show_timer(struct seq_file *m, void *v)
2484{
2485	struct k_itimer *timer;
2486	struct timers_private *tp = m->private;
2487	int notify;
2488	static const char * const nstr[] = {
2489		[SIGEV_SIGNAL] = "signal",
2490		[SIGEV_NONE] = "none",
2491		[SIGEV_THREAD] = "thread",
2492	};
2493
2494	timer = list_entry((struct list_head *)v, struct k_itimer, list);
2495	notify = timer->it_sigev_notify;
2496
2497	seq_printf(m, "ID: %d\n", timer->it_id);
2498	seq_printf(m, "signal: %d/%px\n",
2499		   timer->sigq->info.si_signo,
2500		   timer->sigq->info.si_value.sival_ptr);
2501	seq_printf(m, "notify: %s/%s.%d\n",
2502		   nstr[notify & ~SIGEV_THREAD_ID],
2503		   (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2504		   pid_nr_ns(timer->it_pid, tp->ns));
2505	seq_printf(m, "ClockID: %d\n", timer->it_clock);
2506
2507	return 0;
2508}
2509
2510static const struct seq_operations proc_timers_seq_ops = {
2511	.start	= timers_start,
2512	.next	= timers_next,
2513	.stop	= timers_stop,
2514	.show	= show_timer,
2515};
2516
2517static int proc_timers_open(struct inode *inode, struct file *file)
2518{
2519	struct timers_private *tp;
2520
2521	tp = __seq_open_private(file, &proc_timers_seq_ops,
2522			sizeof(struct timers_private));
2523	if (!tp)
2524		return -ENOMEM;
2525
2526	tp->pid = proc_pid(inode);
2527	tp->ns = proc_pid_ns(inode->i_sb);
2528	return 0;
2529}
2530
2531static const struct file_operations proc_timers_operations = {
2532	.open		= proc_timers_open,
2533	.read		= seq_read,
2534	.llseek		= seq_lseek,
2535	.release	= seq_release_private,
2536};
2537#endif
2538
2539static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2540					size_t count, loff_t *offset)
2541{
2542	struct inode *inode = file_inode(file);
2543	struct task_struct *p;
2544	u64 slack_ns;
2545	int err;
2546
2547	err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2548	if (err < 0)
2549		return err;
2550
2551	p = get_proc_task(inode);
2552	if (!p)
2553		return -ESRCH;
2554
2555	if (p != current) {
2556		rcu_read_lock();
2557		if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
2558			rcu_read_unlock();
2559			count = -EPERM;
2560			goto out;
2561		}
2562		rcu_read_unlock();
2563
2564		err = security_task_setscheduler(p);
2565		if (err) {
2566			count = err;
2567			goto out;
2568		}
2569	}
2570
2571	task_lock(p);
2572	if (slack_ns == 0)
2573		p->timer_slack_ns = p->default_timer_slack_ns;
2574	else
2575		p->timer_slack_ns = slack_ns;
 
2576	task_unlock(p);
2577
2578out:
2579	put_task_struct(p);
2580
2581	return count;
2582}
2583
2584static int timerslack_ns_show(struct seq_file *m, void *v)
2585{
2586	struct inode *inode = m->private;
2587	struct task_struct *p;
2588	int err = 0;
2589
2590	p = get_proc_task(inode);
2591	if (!p)
2592		return -ESRCH;
2593
2594	if (p != current) {
2595		rcu_read_lock();
2596		if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
2597			rcu_read_unlock();
2598			err = -EPERM;
2599			goto out;
2600		}
2601		rcu_read_unlock();
2602
2603		err = security_task_getscheduler(p);
2604		if (err)
2605			goto out;
2606	}
2607
2608	task_lock(p);
2609	seq_printf(m, "%llu\n", p->timer_slack_ns);
2610	task_unlock(p);
2611
2612out:
2613	put_task_struct(p);
2614
2615	return err;
2616}
2617
2618static int timerslack_ns_open(struct inode *inode, struct file *filp)
2619{
2620	return single_open(filp, timerslack_ns_show, inode);
2621}
2622
2623static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2624	.open		= timerslack_ns_open,
2625	.read		= seq_read,
2626	.write		= timerslack_ns_write,
2627	.llseek		= seq_lseek,
2628	.release	= single_release,
2629};
2630
2631static struct dentry *proc_pident_instantiate(struct dentry *dentry,
2632	struct task_struct *task, const void *ptr)
2633{
2634	const struct pid_entry *p = ptr;
2635	struct inode *inode;
2636	struct proc_inode *ei;
2637
2638	inode = proc_pid_make_inode(dentry->d_sb, task, p->mode);
2639	if (!inode)
2640		return ERR_PTR(-ENOENT);
2641
2642	ei = PROC_I(inode);
2643	if (S_ISDIR(inode->i_mode))
2644		set_nlink(inode, 2);	/* Use getattr to fix if necessary */
2645	if (p->iop)
2646		inode->i_op = p->iop;
2647	if (p->fop)
2648		inode->i_fop = p->fop;
2649	ei->op = p->op;
2650	pid_update_inode(task, inode);
2651	d_set_d_op(dentry, &pid_dentry_operations);
2652	return d_splice_alias(inode, dentry);
2653}
2654
2655static struct dentry *proc_pident_lookup(struct inode *dir, 
2656					 struct dentry *dentry,
2657					 const struct pid_entry *p,
2658					 const struct pid_entry *end)
2659{
2660	struct task_struct *task = get_proc_task(dir);
2661	struct dentry *res = ERR_PTR(-ENOENT);
2662
2663	if (!task)
2664		goto out_no_task;
2665
2666	/*
2667	 * Yes, it does not scale. And it should not. Don't add
2668	 * new entries into /proc/<tgid>/ without very good reasons.
2669	 */
2670	for (; p < end; p++) {
2671		if (p->len != dentry->d_name.len)
2672			continue;
2673		if (!memcmp(dentry->d_name.name, p->name, p->len)) {
2674			res = proc_pident_instantiate(dentry, task, p);
2675			break;
2676		}
2677	}
2678	put_task_struct(task);
2679out_no_task:
2680	return res;
2681}
2682
2683static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2684		const struct pid_entry *ents, unsigned int nents)
2685{
2686	struct task_struct *task = get_proc_task(file_inode(file));
2687	const struct pid_entry *p;
2688
2689	if (!task)
2690		return -ENOENT;
2691
2692	if (!dir_emit_dots(file, ctx))
2693		goto out;
2694
2695	if (ctx->pos >= nents + 2)
2696		goto out;
2697
2698	for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
2699		if (!proc_fill_cache(file, ctx, p->name, p->len,
2700				proc_pident_instantiate, task, p))
2701			break;
2702		ctx->pos++;
2703	}
2704out:
2705	put_task_struct(task);
2706	return 0;
2707}
2708
2709#ifdef CONFIG_SECURITY
2710static int proc_pid_attr_open(struct inode *inode, struct file *file)
2711{
2712	file->private_data = NULL;
2713	__mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
2714	return 0;
2715}
2716
2717static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2718				  size_t count, loff_t *ppos)
2719{
2720	struct inode * inode = file_inode(file);
2721	char *p = NULL;
2722	ssize_t length;
2723	struct task_struct *task = get_proc_task(inode);
2724
2725	if (!task)
2726		return -ESRCH;
2727
2728	length = security_getprocattr(task, PROC_I(inode)->op.lsmid,
2729				      file->f_path.dentry->d_name.name,
2730				      &p);
2731	put_task_struct(task);
2732	if (length > 0)
2733		length = simple_read_from_buffer(buf, count, ppos, p, length);
2734	kfree(p);
2735	return length;
2736}
2737
2738static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2739				   size_t count, loff_t *ppos)
2740{
2741	struct inode * inode = file_inode(file);
2742	struct task_struct *task;
2743	void *page;
2744	int rv;
2745
2746	/* A task may only write when it was the opener. */
2747	if (file->private_data != current->mm)
2748		return -EPERM;
2749
2750	rcu_read_lock();
2751	task = pid_task(proc_pid(inode), PIDTYPE_PID);
2752	if (!task) {
2753		rcu_read_unlock();
2754		return -ESRCH;
2755	}
2756	/* A task may only write its own attributes. */
2757	if (current != task) {
2758		rcu_read_unlock();
2759		return -EACCES;
2760	}
2761	/* Prevent changes to overridden credentials. */
2762	if (current_cred() != current_real_cred()) {
2763		rcu_read_unlock();
2764		return -EBUSY;
2765	}
2766	rcu_read_unlock();
2767
2768	if (count > PAGE_SIZE)
2769		count = PAGE_SIZE;
2770
2771	/* No partial writes. */
2772	if (*ppos != 0)
2773		return -EINVAL;
2774
2775	page = memdup_user(buf, count);
2776	if (IS_ERR(page)) {
2777		rv = PTR_ERR(page);
2778		goto out;
2779	}
2780
2781	/* Guard against adverse ptrace interaction */
2782	rv = mutex_lock_interruptible(&current->signal->cred_guard_mutex);
2783	if (rv < 0)
2784		goto out_free;
2785
2786	rv = security_setprocattr(PROC_I(inode)->op.lsmid,
2787				  file->f_path.dentry->d_name.name, page,
2788				  count);
2789	mutex_unlock(&current->signal->cred_guard_mutex);
2790out_free:
2791	kfree(page);
2792out:
2793	return rv;
2794}
2795
2796static const struct file_operations proc_pid_attr_operations = {
2797	.open		= proc_pid_attr_open,
2798	.read		= proc_pid_attr_read,
2799	.write		= proc_pid_attr_write,
2800	.llseek		= generic_file_llseek,
2801	.release	= mem_release,
2802};
2803
2804#define LSM_DIR_OPS(LSM) \
2805static int proc_##LSM##_attr_dir_iterate(struct file *filp, \
2806			     struct dir_context *ctx) \
2807{ \
2808	return proc_pident_readdir(filp, ctx, \
2809				   LSM##_attr_dir_stuff, \
2810				   ARRAY_SIZE(LSM##_attr_dir_stuff)); \
2811} \
2812\
2813static const struct file_operations proc_##LSM##_attr_dir_ops = { \
2814	.read		= generic_read_dir, \
2815	.iterate_shared	= proc_##LSM##_attr_dir_iterate, \
2816	.llseek		= default_llseek, \
2817}; \
2818\
2819static struct dentry *proc_##LSM##_attr_dir_lookup(struct inode *dir, \
2820				struct dentry *dentry, unsigned int flags) \
2821{ \
2822	return proc_pident_lookup(dir, dentry, \
2823				  LSM##_attr_dir_stuff, \
2824				  LSM##_attr_dir_stuff + ARRAY_SIZE(LSM##_attr_dir_stuff)); \
2825} \
2826\
2827static const struct inode_operations proc_##LSM##_attr_dir_inode_ops = { \
2828	.lookup		= proc_##LSM##_attr_dir_lookup, \
2829	.getattr	= pid_getattr, \
2830	.setattr	= proc_setattr, \
2831}
2832
2833#ifdef CONFIG_SECURITY_SMACK
2834static const struct pid_entry smack_attr_dir_stuff[] = {
2835	ATTR(LSM_ID_SMACK, "current",	0666),
2836};
2837LSM_DIR_OPS(smack);
2838#endif
2839
2840#ifdef CONFIG_SECURITY_APPARMOR
2841static const struct pid_entry apparmor_attr_dir_stuff[] = {
2842	ATTR(LSM_ID_APPARMOR, "current",	0666),
2843	ATTR(LSM_ID_APPARMOR, "prev",		0444),
2844	ATTR(LSM_ID_APPARMOR, "exec",		0666),
2845};
2846LSM_DIR_OPS(apparmor);
2847#endif
2848
2849static const struct pid_entry attr_dir_stuff[] = {
2850	ATTR(LSM_ID_UNDEF, "current",	0666),
2851	ATTR(LSM_ID_UNDEF, "prev",		0444),
2852	ATTR(LSM_ID_UNDEF, "exec",		0666),
2853	ATTR(LSM_ID_UNDEF, "fscreate",	0666),
2854	ATTR(LSM_ID_UNDEF, "keycreate",	0666),
2855	ATTR(LSM_ID_UNDEF, "sockcreate",	0666),
2856#ifdef CONFIG_SECURITY_SMACK
2857	DIR("smack",			0555,
2858	    proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
2859#endif
2860#ifdef CONFIG_SECURITY_APPARMOR
2861	DIR("apparmor",			0555,
2862	    proc_apparmor_attr_dir_inode_ops, proc_apparmor_attr_dir_ops),
2863#endif
2864};
2865
2866static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2867{
2868	return proc_pident_readdir(file, ctx, 
2869				   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2870}
2871
2872static const struct file_operations proc_attr_dir_operations = {
2873	.read		= generic_read_dir,
2874	.iterate_shared	= proc_attr_dir_readdir,
2875	.llseek		= generic_file_llseek,
2876};
2877
2878static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2879				struct dentry *dentry, unsigned int flags)
2880{
2881	return proc_pident_lookup(dir, dentry,
2882				  attr_dir_stuff,
2883				  attr_dir_stuff + ARRAY_SIZE(attr_dir_stuff));
2884}
2885
2886static const struct inode_operations proc_attr_dir_inode_operations = {
2887	.lookup		= proc_attr_dir_lookup,
2888	.getattr	= pid_getattr,
2889	.setattr	= proc_setattr,
2890};
2891
2892#endif
2893
2894#ifdef CONFIG_ELF_CORE
2895static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2896					 size_t count, loff_t *ppos)
2897{
2898	struct task_struct *task = get_proc_task(file_inode(file));
2899	struct mm_struct *mm;
2900	char buffer[PROC_NUMBUF];
2901	size_t len;
2902	int ret;
2903
2904	if (!task)
2905		return -ESRCH;
2906
2907	ret = 0;
2908	mm = get_task_mm(task);
2909	if (mm) {
2910		len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2911			       ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2912				MMF_DUMP_FILTER_SHIFT));
2913		mmput(mm);
2914		ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2915	}
2916
2917	put_task_struct(task);
2918
2919	return ret;
2920}
2921
2922static ssize_t proc_coredump_filter_write(struct file *file,
2923					  const char __user *buf,
2924					  size_t count,
2925					  loff_t *ppos)
2926{
2927	struct task_struct *task;
2928	struct mm_struct *mm;
2929	unsigned int val;
2930	int ret;
2931	int i;
2932	unsigned long mask;
2933
2934	ret = kstrtouint_from_user(buf, count, 0, &val);
2935	if (ret < 0)
2936		return ret;
2937
2938	ret = -ESRCH;
2939	task = get_proc_task(file_inode(file));
2940	if (!task)
2941		goto out_no_task;
2942
2943	mm = get_task_mm(task);
2944	if (!mm)
2945		goto out_no_mm;
2946	ret = 0;
2947
2948	for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2949		if (val & mask)
2950			set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2951		else
2952			clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2953	}
2954
2955	mmput(mm);
2956 out_no_mm:
2957	put_task_struct(task);
2958 out_no_task:
2959	if (ret < 0)
2960		return ret;
2961	return count;
2962}
2963
2964static const struct file_operations proc_coredump_filter_operations = {
2965	.read		= proc_coredump_filter_read,
2966	.write		= proc_coredump_filter_write,
2967	.llseek		= generic_file_llseek,
2968};
2969#endif
2970
2971#ifdef CONFIG_TASK_IO_ACCOUNTING
2972static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2973{
2974	struct task_io_accounting acct;
2975	int result;
2976
2977	result = down_read_killable(&task->signal->exec_update_lock);
2978	if (result)
2979		return result;
2980
2981	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2982		result = -EACCES;
2983		goto out_unlock;
2984	}
2985
2986	if (whole) {
2987		struct signal_struct *sig = task->signal;
2988		struct task_struct *t;
2989		unsigned int seq = 1;
2990		unsigned long flags;
2991
2992		rcu_read_lock();
2993		do {
2994			seq++; /* 2 on the 1st/lockless path, otherwise odd */
2995			flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
2996
2997			acct = sig->ioac;
2998			__for_each_thread(sig, t)
2999				task_io_accounting_add(&acct, &t->ioac);
3000
3001		} while (need_seqretry(&sig->stats_lock, seq));
3002		done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
3003		rcu_read_unlock();
3004	} else {
3005		acct = task->ioac;
3006	}
3007
3008	seq_printf(m,
3009		   "rchar: %llu\n"
3010		   "wchar: %llu\n"
3011		   "syscr: %llu\n"
3012		   "syscw: %llu\n"
3013		   "read_bytes: %llu\n"
3014		   "write_bytes: %llu\n"
3015		   "cancelled_write_bytes: %llu\n",
3016		   (unsigned long long)acct.rchar,
3017		   (unsigned long long)acct.wchar,
3018		   (unsigned long long)acct.syscr,
3019		   (unsigned long long)acct.syscw,
3020		   (unsigned long long)acct.read_bytes,
3021		   (unsigned long long)acct.write_bytes,
3022		   (unsigned long long)acct.cancelled_write_bytes);
3023	result = 0;
3024
3025out_unlock:
3026	up_read(&task->signal->exec_update_lock);
3027	return result;
3028}
3029
3030static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
3031				  struct pid *pid, struct task_struct *task)
3032{
3033	return do_io_accounting(task, m, 0);
3034}
3035
3036static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
3037				   struct pid *pid, struct task_struct *task)
3038{
3039	return do_io_accounting(task, m, 1);
3040}
3041#endif /* CONFIG_TASK_IO_ACCOUNTING */
3042
3043#ifdef CONFIG_USER_NS
3044static int proc_id_map_open(struct inode *inode, struct file *file,
3045	const struct seq_operations *seq_ops)
3046{
3047	struct user_namespace *ns = NULL;
3048	struct task_struct *task;
3049	struct seq_file *seq;
3050	int ret = -EINVAL;
3051
3052	task = get_proc_task(inode);
3053	if (task) {
3054		rcu_read_lock();
3055		ns = get_user_ns(task_cred_xxx(task, user_ns));
3056		rcu_read_unlock();
3057		put_task_struct(task);
3058	}
3059	if (!ns)
3060		goto err;
3061
3062	ret = seq_open(file, seq_ops);
3063	if (ret)
3064		goto err_put_ns;
3065
3066	seq = file->private_data;
3067	seq->private = ns;
3068
3069	return 0;
3070err_put_ns:
3071	put_user_ns(ns);
3072err:
3073	return ret;
3074}
3075
3076static int proc_id_map_release(struct inode *inode, struct file *file)
3077{
3078	struct seq_file *seq = file->private_data;
3079	struct user_namespace *ns = seq->private;
3080	put_user_ns(ns);
3081	return seq_release(inode, file);
3082}
3083
3084static int proc_uid_map_open(struct inode *inode, struct file *file)
3085{
3086	return proc_id_map_open(inode, file, &proc_uid_seq_operations);
3087}
3088
3089static int proc_gid_map_open(struct inode *inode, struct file *file)
3090{
3091	return proc_id_map_open(inode, file, &proc_gid_seq_operations);
3092}
3093
3094static int proc_projid_map_open(struct inode *inode, struct file *file)
3095{
3096	return proc_id_map_open(inode, file, &proc_projid_seq_operations);
3097}
3098
3099static const struct file_operations proc_uid_map_operations = {
3100	.open		= proc_uid_map_open,
3101	.write		= proc_uid_map_write,
3102	.read		= seq_read,
3103	.llseek		= seq_lseek,
3104	.release	= proc_id_map_release,
3105};
3106
3107static const struct file_operations proc_gid_map_operations = {
3108	.open		= proc_gid_map_open,
3109	.write		= proc_gid_map_write,
3110	.read		= seq_read,
3111	.llseek		= seq_lseek,
3112	.release	= proc_id_map_release,
3113};
3114
3115static const struct file_operations proc_projid_map_operations = {
3116	.open		= proc_projid_map_open,
3117	.write		= proc_projid_map_write,
3118	.read		= seq_read,
3119	.llseek		= seq_lseek,
3120	.release	= proc_id_map_release,
3121};
3122
3123static int proc_setgroups_open(struct inode *inode, struct file *file)
3124{
3125	struct user_namespace *ns = NULL;
3126	struct task_struct *task;
3127	int ret;
3128
3129	ret = -ESRCH;
3130	task = get_proc_task(inode);
3131	if (task) {
3132		rcu_read_lock();
3133		ns = get_user_ns(task_cred_xxx(task, user_ns));
3134		rcu_read_unlock();
3135		put_task_struct(task);
3136	}
3137	if (!ns)
3138		goto err;
3139
3140	if (file->f_mode & FMODE_WRITE) {
3141		ret = -EACCES;
3142		if (!ns_capable(ns, CAP_SYS_ADMIN))
3143			goto err_put_ns;
3144	}
3145
3146	ret = single_open(file, &proc_setgroups_show, ns);
3147	if (ret)
3148		goto err_put_ns;
3149
3150	return 0;
3151err_put_ns:
3152	put_user_ns(ns);
3153err:
3154	return ret;
3155}
3156
3157static int proc_setgroups_release(struct inode *inode, struct file *file)
3158{
3159	struct seq_file *seq = file->private_data;
3160	struct user_namespace *ns = seq->private;
3161	int ret = single_release(inode, file);
3162	put_user_ns(ns);
3163	return ret;
3164}
3165
3166static const struct file_operations proc_setgroups_operations = {
3167	.open		= proc_setgroups_open,
3168	.write		= proc_setgroups_write,
3169	.read		= seq_read,
3170	.llseek		= seq_lseek,
3171	.release	= proc_setgroups_release,
3172};
3173#endif /* CONFIG_USER_NS */
3174
3175static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
3176				struct pid *pid, struct task_struct *task)
3177{
3178	int err = lock_trace(task);
3179	if (!err) {
3180		seq_printf(m, "%08x\n", task->personality);
3181		unlock_trace(task);
3182	}
3183	return err;
3184}
3185
3186#ifdef CONFIG_LIVEPATCH
3187static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns,
3188				struct pid *pid, struct task_struct *task)
3189{
3190	seq_printf(m, "%d\n", task->patch_state);
3191	return 0;
3192}
3193#endif /* CONFIG_LIVEPATCH */
3194
3195#ifdef CONFIG_KSM
3196static int proc_pid_ksm_merging_pages(struct seq_file *m, struct pid_namespace *ns,
3197				struct pid *pid, struct task_struct *task)
3198{
3199	struct mm_struct *mm;
3200
3201	mm = get_task_mm(task);
3202	if (mm) {
3203		seq_printf(m, "%lu\n", mm->ksm_merging_pages);
3204		mmput(mm);
3205	}
3206
3207	return 0;
3208}
3209static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns,
3210				struct pid *pid, struct task_struct *task)
3211{
3212	struct mm_struct *mm;
3213
3214	mm = get_task_mm(task);
3215	if (mm) {
3216		seq_printf(m, "ksm_rmap_items %lu\n", mm->ksm_rmap_items);
3217		seq_printf(m, "ksm_zero_pages %lu\n", mm->ksm_zero_pages);
3218		seq_printf(m, "ksm_merging_pages %lu\n", mm->ksm_merging_pages);
3219		seq_printf(m, "ksm_process_profit %ld\n", ksm_process_profit(mm));
3220		mmput(mm);
3221	}
3222
3223	return 0;
3224}
3225#endif /* CONFIG_KSM */
3226
3227#ifdef CONFIG_STACKLEAK_METRICS
3228static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns,
3229				struct pid *pid, struct task_struct *task)
3230{
3231	unsigned long prev_depth = THREAD_SIZE -
3232				(task->prev_lowest_stack & (THREAD_SIZE - 1));
3233	unsigned long depth = THREAD_SIZE -
3234				(task->lowest_stack & (THREAD_SIZE - 1));
3235
3236	seq_printf(m, "previous stack depth: %lu\nstack depth: %lu\n",
3237							prev_depth, depth);
3238	return 0;
3239}
3240#endif /* CONFIG_STACKLEAK_METRICS */
3241
3242/*
3243 * Thread groups
3244 */
3245static const struct file_operations proc_task_operations;
3246static const struct inode_operations proc_task_inode_operations;
3247
3248static const struct pid_entry tgid_base_stuff[] = {
3249	DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
3250	DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3251	DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
3252	DIR("fdinfo",     S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3253	DIR("ns",	  S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3254#ifdef CONFIG_NET
3255	DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3256#endif
3257	REG("environ",    S_IRUSR, proc_environ_operations),
3258	REG("auxv",       S_IRUSR, proc_auxv_operations),
3259	ONE("status",     S_IRUGO, proc_pid_status),
3260	ONE("personality", S_IRUSR, proc_pid_personality),
3261	ONE("limits",	  S_IRUGO, proc_pid_limits),
3262#ifdef CONFIG_SCHED_DEBUG
3263	REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3264#endif
3265#ifdef CONFIG_SCHED_AUTOGROUP
3266	REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
3267#endif
3268#ifdef CONFIG_TIME_NS
3269	REG("timens_offsets",  S_IRUGO|S_IWUSR, proc_timens_offsets_operations),
3270#endif
3271	REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3272#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3273	ONE("syscall",    S_IRUSR, proc_pid_syscall),
3274#endif
3275	REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
3276	ONE("stat",       S_IRUGO, proc_tgid_stat),
3277	ONE("statm",      S_IRUGO, proc_pid_statm),
3278	REG("maps",       S_IRUGO, proc_pid_maps_operations),
3279#ifdef CONFIG_NUMA
3280	REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
3281#endif
3282	REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
3283	LNK("cwd",        proc_cwd_link),
3284	LNK("root",       proc_root_link),
3285	LNK("exe",        proc_exe_link),
3286	REG("mounts",     S_IRUGO, proc_mounts_operations),
3287	REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3288	REG("mountstats", S_IRUSR, proc_mountstats_operations),
3289#ifdef CONFIG_PROC_PAGE_MONITOR
3290	REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3291	REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
3292	REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3293	REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3294#endif
3295#ifdef CONFIG_SECURITY
3296	DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3297#endif
3298#ifdef CONFIG_KALLSYMS
3299	ONE("wchan",      S_IRUGO, proc_pid_wchan),
3300#endif
3301#ifdef CONFIG_STACKTRACE
3302	ONE("stack",      S_IRUSR, proc_pid_stack),
3303#endif
3304#ifdef CONFIG_SCHED_INFO
3305	ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
3306#endif
3307#ifdef CONFIG_LATENCYTOP
3308	REG("latency",  S_IRUGO, proc_lstats_operations),
3309#endif
3310#ifdef CONFIG_PROC_PID_CPUSET
3311	ONE("cpuset",     S_IRUGO, proc_cpuset_show),
3312#endif
3313#ifdef CONFIG_CGROUPS
3314	ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3315#endif
3316#ifdef CONFIG_PROC_CPU_RESCTRL
3317	ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
3318#endif
3319	ONE("oom_score",  S_IRUGO, proc_oom_score),
3320	REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3321	REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3322#ifdef CONFIG_AUDIT
3323	REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
3324	REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3325#endif
3326#ifdef CONFIG_FAULT_INJECTION
3327	REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3328	REG("fail-nth", 0644, proc_fail_nth_operations),
3329#endif
3330#ifdef CONFIG_ELF_CORE
3331	REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
3332#endif
3333#ifdef CONFIG_TASK_IO_ACCOUNTING
3334	ONE("io",	S_IRUSR, proc_tgid_io_accounting),
3335#endif
3336#ifdef CONFIG_USER_NS
3337	REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3338	REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3339	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3340	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3341#endif
3342#if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
3343	REG("timers",	  S_IRUGO, proc_timers_operations),
3344#endif
3345	REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
3346#ifdef CONFIG_LIVEPATCH
3347	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3348#endif
3349#ifdef CONFIG_STACKLEAK_METRICS
3350	ONE("stack_depth", S_IRUGO, proc_stack_depth),
3351#endif
3352#ifdef CONFIG_PROC_PID_ARCH_STATUS
3353	ONE("arch_status", S_IRUGO, proc_pid_arch_status),
3354#endif
3355#ifdef CONFIG_SECCOMP_CACHE_DEBUG
3356	ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
3357#endif
3358#ifdef CONFIG_KSM
3359	ONE("ksm_merging_pages",  S_IRUSR, proc_pid_ksm_merging_pages),
3360	ONE("ksm_stat",  S_IRUSR, proc_pid_ksm_stat),
3361#endif
3362};
3363
3364static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
3365{
3366	return proc_pident_readdir(file, ctx,
3367				   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3368}
3369
3370static const struct file_operations proc_tgid_base_operations = {
3371	.read		= generic_read_dir,
3372	.iterate_shared	= proc_tgid_base_readdir,
3373	.llseek		= generic_file_llseek,
3374};
3375
3376struct pid *tgid_pidfd_to_pid(const struct file *file)
3377{
3378	if (file->f_op != &proc_tgid_base_operations)
3379		return ERR_PTR(-EBADF);
3380
3381	return proc_pid(file_inode(file));
3382}
3383
3384static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3385{
3386	return proc_pident_lookup(dir, dentry,
3387				  tgid_base_stuff,
3388				  tgid_base_stuff + ARRAY_SIZE(tgid_base_stuff));
3389}
3390
3391static const struct inode_operations proc_tgid_base_inode_operations = {
3392	.lookup		= proc_tgid_base_lookup,
3393	.getattr	= pid_getattr,
3394	.setattr	= proc_setattr,
3395	.permission	= proc_pid_permission,
3396};
3397
3398/**
3399 * proc_flush_pid -  Remove dcache entries for @pid from the /proc dcache.
3400 * @pid: pid that should be flushed.
3401 *
3402 * This function walks a list of inodes (that belong to any proc
3403 * filesystem) that are attached to the pid and flushes them from
3404 * the dentry cache.
3405 *
3406 * It is safe and reasonable to cache /proc entries for a task until
3407 * that task exits.  After that they just clog up the dcache with
3408 * useless entries, possibly causing useful dcache entries to be
3409 * flushed instead.  This routine is provided to flush those useless
3410 * dcache entries when a process is reaped.
3411 *
3412 * NOTE: This routine is just an optimization so it does not guarantee
3413 *       that no dcache entries will exist after a process is reaped
3414 *       it just makes it very unlikely that any will persist.
3415 */
3416
3417void proc_flush_pid(struct pid *pid)
3418{
3419	proc_invalidate_siblings_dcache(&pid->inodes, &pid->lock);
3420}
3421
3422static struct dentry *proc_pid_instantiate(struct dentry * dentry,
3423				   struct task_struct *task, const void *ptr)
3424{
3425	struct inode *inode;
3426
3427	inode = proc_pid_make_base_inode(dentry->d_sb, task,
3428					 S_IFDIR | S_IRUGO | S_IXUGO);
3429	if (!inode)
3430		return ERR_PTR(-ENOENT);
3431
3432	inode->i_op = &proc_tgid_base_inode_operations;
3433	inode->i_fop = &proc_tgid_base_operations;
3434	inode->i_flags|=S_IMMUTABLE;
3435
3436	set_nlink(inode, nlink_tgid);
3437	pid_update_inode(task, inode);
3438
3439	d_set_d_op(dentry, &pid_dentry_operations);
3440	return d_splice_alias(inode, dentry);
3441}
3442
3443struct dentry *proc_pid_lookup(struct dentry *dentry, unsigned int flags)
3444{
3445	struct task_struct *task;
3446	unsigned tgid;
3447	struct proc_fs_info *fs_info;
3448	struct pid_namespace *ns;
3449	struct dentry *result = ERR_PTR(-ENOENT);
3450
3451	tgid = name_to_int(&dentry->d_name);
3452	if (tgid == ~0U)
3453		goto out;
3454
3455	fs_info = proc_sb_info(dentry->d_sb);
3456	ns = fs_info->pid_ns;
3457	rcu_read_lock();
3458	task = find_task_by_pid_ns(tgid, ns);
3459	if (task)
3460		get_task_struct(task);
3461	rcu_read_unlock();
3462	if (!task)
3463		goto out;
3464
3465	/* Limit procfs to only ptraceable tasks */
3466	if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE) {
3467		if (!has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS))
3468			goto out_put_task;
3469	}
3470
3471	result = proc_pid_instantiate(dentry, task, NULL);
3472out_put_task:
3473	put_task_struct(task);
3474out:
3475	return result;
3476}
3477
3478/*
3479 * Find the first task with tgid >= tgid
3480 *
3481 */
3482struct tgid_iter {
3483	unsigned int tgid;
3484	struct task_struct *task;
3485};
3486static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3487{
3488	struct pid *pid;
3489
3490	if (iter.task)
3491		put_task_struct(iter.task);
3492	rcu_read_lock();
3493retry:
3494	iter.task = NULL;
3495	pid = find_ge_pid(iter.tgid, ns);
3496	if (pid) {
3497		iter.tgid = pid_nr_ns(pid, ns);
3498		iter.task = pid_task(pid, PIDTYPE_TGID);
3499		if (!iter.task) {
3500			iter.tgid += 1;
3501			goto retry;
3502		}
3503		get_task_struct(iter.task);
3504	}
3505	rcu_read_unlock();
3506	return iter;
3507}
3508
3509#define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3510
3511/* for the /proc/ directory itself, after non-process stuff has been done */
3512int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3513{
3514	struct tgid_iter iter;
3515	struct proc_fs_info *fs_info = proc_sb_info(file_inode(file)->i_sb);
3516	struct pid_namespace *ns = proc_pid_ns(file_inode(file)->i_sb);
3517	loff_t pos = ctx->pos;
3518
3519	if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3520		return 0;
3521
3522	if (pos == TGID_OFFSET - 2) {
3523		struct inode *inode = d_inode(fs_info->proc_self);
3524		if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3525			return 0;
3526		ctx->pos = pos = pos + 1;
3527	}
3528	if (pos == TGID_OFFSET - 1) {
3529		struct inode *inode = d_inode(fs_info->proc_thread_self);
3530		if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3531			return 0;
3532		ctx->pos = pos = pos + 1;
3533	}
3534	iter.tgid = pos - TGID_OFFSET;
3535	iter.task = NULL;
3536	for (iter = next_tgid(ns, iter);
3537	     iter.task;
3538	     iter.tgid += 1, iter = next_tgid(ns, iter)) {
3539		char name[10 + 1];
3540		unsigned int len;
3541
3542		cond_resched();
3543		if (!has_pid_permissions(fs_info, iter.task, HIDEPID_INVISIBLE))
3544			continue;
3545
3546		len = snprintf(name, sizeof(name), "%u", iter.tgid);
3547		ctx->pos = iter.tgid + TGID_OFFSET;
3548		if (!proc_fill_cache(file, ctx, name, len,
3549				     proc_pid_instantiate, iter.task, NULL)) {
3550			put_task_struct(iter.task);
3551			return 0;
3552		}
3553	}
3554	ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3555	return 0;
3556}
3557
3558/*
3559 * proc_tid_comm_permission is a special permission function exclusively
3560 * used for the node /proc/<pid>/task/<tid>/comm.
3561 * It bypasses generic permission checks in the case where a task of the same
3562 * task group attempts to access the node.
3563 * The rationale behind this is that glibc and bionic access this node for
3564 * cross thread naming (pthread_set/getname_np(!self)). However, if
3565 * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3566 * which locks out the cross thread naming implementation.
3567 * This function makes sure that the node is always accessible for members of
3568 * same thread group.
3569 */
3570static int proc_tid_comm_permission(struct mnt_idmap *idmap,
3571				    struct inode *inode, int mask)
3572{
3573	bool is_same_tgroup;
3574	struct task_struct *task;
3575
3576	task = get_proc_task(inode);
3577	if (!task)
3578		return -ESRCH;
3579	is_same_tgroup = same_thread_group(current, task);
3580	put_task_struct(task);
3581
3582	if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3583		/* This file (/proc/<pid>/task/<tid>/comm) can always be
3584		 * read or written by the members of the corresponding
3585		 * thread group.
3586		 */
3587		return 0;
3588	}
3589
3590	return generic_permission(&nop_mnt_idmap, inode, mask);
3591}
3592
3593static const struct inode_operations proc_tid_comm_inode_operations = {
3594		.setattr	= proc_setattr,
3595		.permission	= proc_tid_comm_permission,
3596};
3597
3598/*
3599 * Tasks
3600 */
3601static const struct pid_entry tid_base_stuff[] = {
3602	DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3603	DIR("fdinfo",    S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3604	DIR("ns",	 S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3605#ifdef CONFIG_NET
3606	DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3607#endif
3608	REG("environ",   S_IRUSR, proc_environ_operations),
3609	REG("auxv",      S_IRUSR, proc_auxv_operations),
3610	ONE("status",    S_IRUGO, proc_pid_status),
3611	ONE("personality", S_IRUSR, proc_pid_personality),
3612	ONE("limits",	 S_IRUGO, proc_pid_limits),
3613#ifdef CONFIG_SCHED_DEBUG
3614	REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3615#endif
3616	NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3617			 &proc_tid_comm_inode_operations,
3618			 &proc_pid_set_comm_operations, {}),
3619#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3620	ONE("syscall",   S_IRUSR, proc_pid_syscall),
3621#endif
3622	REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3623	ONE("stat",      S_IRUGO, proc_tid_stat),
3624	ONE("statm",     S_IRUGO, proc_pid_statm),
3625	REG("maps",      S_IRUGO, proc_pid_maps_operations),
3626#ifdef CONFIG_PROC_CHILDREN
3627	REG("children",  S_IRUGO, proc_tid_children_operations),
3628#endif
3629#ifdef CONFIG_NUMA
3630	REG("numa_maps", S_IRUGO, proc_pid_numa_maps_operations),
3631#endif
3632	REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3633	LNK("cwd",       proc_cwd_link),
3634	LNK("root",      proc_root_link),
3635	LNK("exe",       proc_exe_link),
3636	REG("mounts",    S_IRUGO, proc_mounts_operations),
3637	REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3638#ifdef CONFIG_PROC_PAGE_MONITOR
3639	REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3640	REG("smaps",     S_IRUGO, proc_pid_smaps_operations),
3641	REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3642	REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3643#endif
3644#ifdef CONFIG_SECURITY
3645	DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3646#endif
3647#ifdef CONFIG_KALLSYMS
3648	ONE("wchan",     S_IRUGO, proc_pid_wchan),
3649#endif
3650#ifdef CONFIG_STACKTRACE
3651	ONE("stack",      S_IRUSR, proc_pid_stack),
3652#endif
3653#ifdef CONFIG_SCHED_INFO
3654	ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3655#endif
3656#ifdef CONFIG_LATENCYTOP
3657	REG("latency",  S_IRUGO, proc_lstats_operations),
3658#endif
3659#ifdef CONFIG_PROC_PID_CPUSET
3660	ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3661#endif
3662#ifdef CONFIG_CGROUPS
3663	ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3664#endif
3665#ifdef CONFIG_PROC_CPU_RESCTRL
3666	ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
3667#endif
3668	ONE("oom_score", S_IRUGO, proc_oom_score),
3669	REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3670	REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3671#ifdef CONFIG_AUDIT
3672	REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3673	REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3674#endif
3675#ifdef CONFIG_FAULT_INJECTION
3676	REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3677	REG("fail-nth", 0644, proc_fail_nth_operations),
3678#endif
3679#ifdef CONFIG_TASK_IO_ACCOUNTING
3680	ONE("io",	S_IRUSR, proc_tid_io_accounting),
3681#endif
3682#ifdef CONFIG_USER_NS
3683	REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3684	REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3685	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3686	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3687#endif
3688#ifdef CONFIG_LIVEPATCH
3689	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3690#endif
3691#ifdef CONFIG_PROC_PID_ARCH_STATUS
3692	ONE("arch_status", S_IRUGO, proc_pid_arch_status),
3693#endif
3694#ifdef CONFIG_SECCOMP_CACHE_DEBUG
3695	ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
3696#endif
3697#ifdef CONFIG_KSM
3698	ONE("ksm_merging_pages",  S_IRUSR, proc_pid_ksm_merging_pages),
3699	ONE("ksm_stat",  S_IRUSR, proc_pid_ksm_stat),
3700#endif
3701};
3702
3703static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3704{
3705	return proc_pident_readdir(file, ctx,
3706				   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3707}
3708
3709static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3710{
3711	return proc_pident_lookup(dir, dentry,
3712				  tid_base_stuff,
3713				  tid_base_stuff + ARRAY_SIZE(tid_base_stuff));
3714}
3715
3716static const struct file_operations proc_tid_base_operations = {
3717	.read		= generic_read_dir,
3718	.iterate_shared	= proc_tid_base_readdir,
3719	.llseek		= generic_file_llseek,
3720};
3721
3722static const struct inode_operations proc_tid_base_inode_operations = {
3723	.lookup		= proc_tid_base_lookup,
3724	.getattr	= pid_getattr,
3725	.setattr	= proc_setattr,
3726};
3727
3728static struct dentry *proc_task_instantiate(struct dentry *dentry,
3729	struct task_struct *task, const void *ptr)
3730{
3731	struct inode *inode;
3732	inode = proc_pid_make_base_inode(dentry->d_sb, task,
3733					 S_IFDIR | S_IRUGO | S_IXUGO);
3734	if (!inode)
3735		return ERR_PTR(-ENOENT);
3736
3737	inode->i_op = &proc_tid_base_inode_operations;
3738	inode->i_fop = &proc_tid_base_operations;
3739	inode->i_flags |= S_IMMUTABLE;
3740
3741	set_nlink(inode, nlink_tid);
3742	pid_update_inode(task, inode);
3743
3744	d_set_d_op(dentry, &pid_dentry_operations);
3745	return d_splice_alias(inode, dentry);
3746}
3747
3748static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3749{
3750	struct task_struct *task;
3751	struct task_struct *leader = get_proc_task(dir);
3752	unsigned tid;
3753	struct proc_fs_info *fs_info;
3754	struct pid_namespace *ns;
3755	struct dentry *result = ERR_PTR(-ENOENT);
3756
3757	if (!leader)
3758		goto out_no_task;
3759
3760	tid = name_to_int(&dentry->d_name);
3761	if (tid == ~0U)
3762		goto out;
3763
3764	fs_info = proc_sb_info(dentry->d_sb);
3765	ns = fs_info->pid_ns;
3766	rcu_read_lock();
3767	task = find_task_by_pid_ns(tid, ns);
3768	if (task)
3769		get_task_struct(task);
3770	rcu_read_unlock();
3771	if (!task)
3772		goto out;
3773	if (!same_thread_group(leader, task))
3774		goto out_drop_task;
3775
3776	result = proc_task_instantiate(dentry, task, NULL);
3777out_drop_task:
3778	put_task_struct(task);
3779out:
3780	put_task_struct(leader);
3781out_no_task:
3782	return result;
3783}
3784
3785/*
3786 * Find the first tid of a thread group to return to user space.
3787 *
3788 * Usually this is just the thread group leader, but if the users
3789 * buffer was too small or there was a seek into the middle of the
3790 * directory we have more work todo.
3791 *
3792 * In the case of a short read we start with find_task_by_pid.
3793 *
3794 * In the case of a seek we start with the leader and walk nr
3795 * threads past it.
3796 */
3797static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3798					struct pid_namespace *ns)
3799{
3800	struct task_struct *pos, *task;
3801	unsigned long nr = f_pos;
3802
3803	if (nr != f_pos)	/* 32bit overflow? */
3804		return NULL;
3805
3806	rcu_read_lock();
3807	task = pid_task(pid, PIDTYPE_PID);
3808	if (!task)
3809		goto fail;
3810
3811	/* Attempt to start with the tid of a thread */
3812	if (tid && nr) {
3813		pos = find_task_by_pid_ns(tid, ns);
3814		if (pos && same_thread_group(pos, task))
3815			goto found;
3816	}
3817
3818	/* If nr exceeds the number of threads there is nothing todo */
3819	if (nr >= get_nr_threads(task))
3820		goto fail;
3821
3822	/* If we haven't found our starting place yet start
3823	 * with the leader and walk nr threads forward.
3824	 */
3825	for_each_thread(task, pos) {
3826		if (!nr--)
3827			goto found;
3828	}
3829fail:
3830	pos = NULL;
3831	goto out;
3832found:
3833	get_task_struct(pos);
3834out:
3835	rcu_read_unlock();
3836	return pos;
3837}
3838
3839/*
3840 * Find the next thread in the thread list.
3841 * Return NULL if there is an error or no next thread.
3842 *
3843 * The reference to the input task_struct is released.
3844 */
3845static struct task_struct *next_tid(struct task_struct *start)
3846{
3847	struct task_struct *pos = NULL;
3848	rcu_read_lock();
3849	if (pid_alive(start)) {
3850		pos = __next_thread(start);
3851		if (pos)
3852			get_task_struct(pos);
3853	}
3854	rcu_read_unlock();
3855	put_task_struct(start);
3856	return pos;
3857}
3858
3859/* for the /proc/TGID/task/ directories */
3860static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3861{
3862	struct inode *inode = file_inode(file);
3863	struct task_struct *task;
3864	struct pid_namespace *ns;
3865	int tid;
3866
3867	if (proc_inode_is_dead(inode))
3868		return -ENOENT;
3869
3870	if (!dir_emit_dots(file, ctx))
3871		return 0;
3872
3873	/* f_version caches the tgid value that the last readdir call couldn't
3874	 * return. lseek aka telldir automagically resets f_version to 0.
3875	 */
3876	ns = proc_pid_ns(inode->i_sb);
3877	tid = (int)file->f_version;
3878	file->f_version = 0;
3879	for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3880	     task;
3881	     task = next_tid(task), ctx->pos++) {
3882		char name[10 + 1];
3883		unsigned int len;
3884
3885		tid = task_pid_nr_ns(task, ns);
3886		if (!tid)
3887			continue;	/* The task has just exited. */
3888		len = snprintf(name, sizeof(name), "%u", tid);
3889		if (!proc_fill_cache(file, ctx, name, len,
3890				proc_task_instantiate, task, NULL)) {
3891			/* returning this tgid failed, save it as the first
3892			 * pid for the next readir call */
3893			file->f_version = (u64)tid;
3894			put_task_struct(task);
3895			break;
3896		}
3897	}
3898
3899	return 0;
3900}
3901
3902static int proc_task_getattr(struct mnt_idmap *idmap,
3903			     const struct path *path, struct kstat *stat,
3904			     u32 request_mask, unsigned int query_flags)
3905{
3906	struct inode *inode = d_inode(path->dentry);
3907	struct task_struct *p = get_proc_task(inode);
3908	generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
3909
3910	if (p) {
3911		stat->nlink += get_nr_threads(p);
3912		put_task_struct(p);
3913	}
3914
3915	return 0;
3916}
3917
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3918static const struct inode_operations proc_task_inode_operations = {
3919	.lookup		= proc_task_lookup,
3920	.getattr	= proc_task_getattr,
3921	.setattr	= proc_setattr,
3922	.permission	= proc_pid_permission,
3923};
3924
3925static const struct file_operations proc_task_operations = {
3926	.read		= generic_read_dir,
3927	.iterate_shared	= proc_task_readdir,
3928	.llseek		= generic_file_llseek,
3929};
3930
3931void __init set_proc_pid_nlink(void)
3932{
3933	nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3934	nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3935}