blob: da8c358930fbf48d9447df2509e88adbb67ea00e [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/kernel/ptrace.c
3 *
4 * (C) Copyright 1999 Linus Torvalds
5 *
6 * Common interfaces for "ptrace()" which we do not want
7 * to continually duplicate across every architecture.
8 */
9
Randy.Dunlapc59ede72006-01-11 12:17:46 -080010#include <linux/capability.h>
Paul Gortmaker9984de12011-05-23 14:51:41 -040011#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/sched.h>
13#include <linux/errno.h>
14#include <linux/mm.h>
15#include <linux/highmem.h>
16#include <linux/pagemap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/ptrace.h>
18#include <linux/security.h>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070019#include <linux/signal.h>
Kent Overstreeta27bb332013-05-07 16:19:08 -070020#include <linux/uio.h>
Al Viroa5cb0132007-03-20 13:58:35 -040021#include <linux/audit.h>
Pavel Emelyanovb4888932007-10-18 23:40:14 -070022#include <linux/pid_namespace.h>
Adrian Bunkf17d30a2008-02-06 01:36:44 -080023#include <linux/syscalls.h>
Roland McGrath3a709702009-04-07 23:21:06 -070024#include <linux/uaccess.h>
Suresh Siddha2225a122010-02-11 11:51:00 -080025#include <linux/regset.h>
Frederic Weisbeckerbf26c012011-04-07 16:53:20 +020026#include <linux/hw_breakpoint.h>
Vladimir Zapolskiyf701e5b2011-07-15 20:45:18 +030027#include <linux/cn_proc.h>
Andrey Vagin84c751b2013-04-30 15:27:59 -070028#include <linux/compat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
Markus Metzgerbf53de92008-12-19 15:10:24 +010030
Eric W. Biedermanc94bea22017-05-22 15:40:12 -050031void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
32 const struct cred *ptracer_cred)
33{
34 BUG_ON(!list_empty(&child->ptrace_entry));
35 list_add(&child->ptrace_entry, &new_parent->ptraced);
36 child->parent = new_parent;
37 child->ptracer_cred = get_cred(ptracer_cred);
38}
39
Markus Metzgerbf53de92008-12-19 15:10:24 +010040/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 * ptrace a task: make the debugger its new parent and
42 * move it to the ptrace list.
43 *
44 * Must be called with the tasklist lock write-held.
45 */
Eric W. Biedermanc94bea22017-05-22 15:40:12 -050046static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -070047{
Jann Horn54562d22019-07-04 17:32:23 +020048 __ptrace_link(child, new_parent, current_cred());
Linus Torvalds1da177e2005-04-16 15:20:36 -070049}
Roland McGrath3a709702009-04-07 23:21:06 -070050
Tejun Heoe3bd0582011-03-23 10:37:01 +010051/**
52 * __ptrace_unlink - unlink ptracee and restore its execution state
53 * @child: ptracee to be unlinked
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 *
Tejun Heo0e9f0a42011-03-23 10:37:01 +010055 * Remove @child from the ptrace list, move it back to the original parent,
56 * and restore the execution state so that it conforms to the group stop
57 * state.
58 *
59 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
60 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
61 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
62 * If the ptracer is exiting, the ptracee can be in any state.
63 *
64 * After detach, the ptracee should be in a state which conforms to the
65 * group stop. If the group is stopped or in the process of stopping, the
66 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
67 * up from TASK_TRACED.
68 *
69 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
70 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
71 * to but in the opposite direction of what happens while attaching to a
72 * stopped task. However, in this direction, the intermediate RUNNING
73 * state is not hidden even from the current ptracer and if it immediately
74 * re-attaches and performs a WNOHANG wait(2), it may fail.
Tejun Heoe3bd0582011-03-23 10:37:01 +010075 *
76 * CONTEXT:
77 * write_lock_irq(tasklist_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 */
Ingo Molnar36c8b582006-07-03 00:25:41 -070079void __ptrace_unlink(struct task_struct *child)
Linus Torvalds1da177e2005-04-16 15:20:36 -070080{
Eric W. Biederman1c1f15f2016-11-14 18:48:07 -060081 const struct cred *old_cred;
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +030082 BUG_ON(!child->ptrace);
83
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 child->ptrace = 0;
Roland McGrathf4700212008-03-24 18:36:23 -070085 child->parent = child->real_parent;
86 list_del_init(&child->ptrace_entry);
Eric W. Biederman1c1f15f2016-11-14 18:48:07 -060087 old_cred = child->ptracer_cred;
88 child->ptracer_cred = NULL;
89 put_cred(old_cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 spin_lock(&child->sighand->siglock);
Tejun Heo0e9f0a42011-03-23 10:37:01 +010092
93 /*
Tejun Heo73ddff22011-06-14 11:20:14 +020094 * Clear all pending traps and TRAPPING. TRAPPING should be
95 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
96 */
97 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
98 task_clear_jobctl_trapping(child);
99
100 /*
Tejun Heoa8f072c2011-06-02 11:13:59 +0200101 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
Tejun Heo0e9f0a42011-03-23 10:37:01 +0100102 * @child isn't dead.
103 */
104 if (!(child->flags & PF_EXITING) &&
105 (child->signal->flags & SIGNAL_STOP_STOPPED ||
Oleg Nesterov8a889512012-01-04 17:29:20 +0100106 child->signal->group_stop_count)) {
Tejun Heoa8f072c2011-06-02 11:13:59 +0200107 child->jobctl |= JOBCTL_STOP_PENDING;
Tejun Heo0e9f0a42011-03-23 10:37:01 +0100108
Oleg Nesterov8a889512012-01-04 17:29:20 +0100109 /*
110 * This is only possible if this thread was cloned by the
111 * traced task running in the stopped group, set the signal
112 * for the future reports.
113 * FIXME: we should change ptrace_init_task() to handle this
114 * case.
115 */
116 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
117 child->jobctl |= SIGSTOP;
118 }
119
Tejun Heo0e9f0a42011-03-23 10:37:01 +0100120 /*
121 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
122 * @child in the butt. Note that @resume should be used iff @child
123 * is in TASK_TRACED; otherwise, we might unduly disrupt
124 * TASK_KILLABLE sleeps.
125 */
Tejun Heoa8f072c2011-06-02 11:13:59 +0200126 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
Oleg Nesterov910ffdb2013-01-21 20:47:41 +0100127 ptrace_signal_wake_up(child, true);
Tejun Heo0e9f0a42011-03-23 10:37:01 +0100128
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 spin_unlock(&child->sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130}
131
Oleg Nesterov9899d112013-01-21 20:48:00 +0100132/* Ensure that nothing can wake it up, even SIGKILL */
133static bool ptrace_freeze_traced(struct task_struct *task)
134{
135 bool ret = false;
136
137 /* Lockless, nobody but us can set this flag */
138 if (task->jobctl & JOBCTL_LISTENING)
139 return ret;
140
141 spin_lock_irq(&task->sighand->siglock);
142 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
143 task->state = __TASK_TRACED;
144 ret = true;
145 }
146 spin_unlock_irq(&task->sighand->siglock);
147
148 return ret;
149}
150
151static void ptrace_unfreeze_traced(struct task_struct *task)
152{
153 if (task->state != __TASK_TRACED)
154 return;
155
156 WARN_ON(!task->ptrace || task->parent != current);
157
bsegall@google.com926e1ed2017-04-07 16:04:51 -0700158 /*
159 * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
160 * Recheck state under the lock to close this race.
161 */
Oleg Nesterov9899d112013-01-21 20:48:00 +0100162 spin_lock_irq(&task->sighand->siglock);
bsegall@google.com926e1ed2017-04-07 16:04:51 -0700163 if (task->state == __TASK_TRACED) {
164 if (__fatal_signal_pending(task))
165 wake_up_state(task, __TASK_TRACED);
166 else
167 task->state = TASK_TRACED;
168 }
Oleg Nesterov9899d112013-01-21 20:48:00 +0100169 spin_unlock_irq(&task->sighand->siglock);
170}
171
Tejun Heo755e2762011-06-02 11:13:59 +0200172/**
173 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
174 * @child: ptracee to check for
175 * @ignore_state: don't check whether @child is currently %TASK_TRACED
176 *
177 * Check whether @child is being ptraced by %current and ready for further
178 * ptrace operations. If @ignore_state is %false, @child also should be in
179 * %TASK_TRACED state and on return the child is guaranteed to be traced
180 * and not executing. If @ignore_state is %true, @child can be in any
181 * state.
182 *
183 * CONTEXT:
184 * Grabs and releases tasklist_lock and @child->sighand->siglock.
185 *
186 * RETURNS:
187 * 0 on success, -ESRCH if %child is not ready.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 */
Oleg Nesterovedea0d02013-01-20 20:25:47 +0100189static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190{
191 int ret = -ESRCH;
192
193 /*
194 * We take the read lock around doing both checks to close a
195 * possible race where someone else was tracing our child and
196 * detached between these two checks. After this locked check,
197 * we are sure that this is our traced child and that can only
198 * be changed by us so it's not changing right after this.
199 */
200 read_lock(&tasklist_lock);
Oleg Nesterov9899d112013-01-21 20:48:00 +0100201 if (child->ptrace && child->parent == current) {
202 WARN_ON(child->state == __TASK_TRACED);
Oleg Nesterovc0c0b642008-02-08 04:19:00 -0800203 /*
204 * child->sighand can't be NULL, release_task()
205 * does ptrace_unlink() before __exit_signal().
206 */
Oleg Nesterov9899d112013-01-21 20:48:00 +0100207 if (ignore_state || ptrace_freeze_traced(child))
Oleg Nesterov321fb562011-04-01 20:13:01 +0200208 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 }
210 read_unlock(&tasklist_lock);
211
Oleg Nesterov9899d112013-01-21 20:48:00 +0100212 if (!ret && !ignore_state) {
213 if (!wait_task_inactive(child, __TASK_TRACED)) {
214 /*
215 * This can only happen if may_ptrace_stop() fails and
216 * ptrace_stop() changes ->state back to TASK_RUNNING,
217 * so we should not worry about leaking __TASK_TRACED.
218 */
219 WARN_ON(child->state == __TASK_TRACED);
220 ret = -ESRCH;
221 }
222 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 return ret;
225}
226
Eric Paris69f594a2012-01-03 12:25:15 -0500227static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
228{
Jiri Kosina4a215a12018-09-25 14:38:18 +0200229 if (mode & PTRACE_MODE_SCHED)
230 return false;
231
Eric Paris69f594a2012-01-03 12:25:15 -0500232 if (mode & PTRACE_MODE_NOAUDIT)
233 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
234 else
235 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
236}
237
Tetsuo Handa9f997982012-07-31 20:37:00 +0900238/* Returns 0 on success, -errno on denial. */
239static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700240{
David Howellsc69e8d92008-11-14 10:39:19 +1100241 const struct cred *cred = current_cred(), *tcred;
Eric W. Biederman03eed7a2016-10-13 21:23:16 -0500242 struct mm_struct *mm;
Jann Horn969624b2016-01-20 15:00:04 -0800243 kuid_t caller_uid;
244 kgid_t caller_gid;
245
246 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
247 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
248 return -EPERM;
249 }
David Howellsb6dff3e2008-11-14 10:39:16 +1100250
Eric W. Biedermandf26c402006-06-26 00:25:59 -0700251 /* May we inspect the given task?
252 * This check is used both for attaching with ptrace
253 * and for allowing access to sensitive information in /proc.
254 *
255 * ptrace_attach denies several cases that /proc allows
256 * because setting up the necessary parent/child relationship
257 * or halting the specified task is impossible.
258 */
Jann Horn969624b2016-01-20 15:00:04 -0800259
Eric W. Biedermandf26c402006-06-26 00:25:59 -0700260 /* Don't let security modules deny introspection */
Mark Grondona73af9632013-09-11 14:24:31 -0700261 if (same_thread_group(task, current))
Eric W. Biedermandf26c402006-06-26 00:25:59 -0700262 return 0;
David Howellsc69e8d92008-11-14 10:39:19 +1100263 rcu_read_lock();
Jann Horn969624b2016-01-20 15:00:04 -0800264 if (mode & PTRACE_MODE_FSCREDS) {
265 caller_uid = cred->fsuid;
266 caller_gid = cred->fsgid;
267 } else {
268 /*
269 * Using the euid would make more sense here, but something
270 * in userland might rely on the old behavior, and this
271 * shouldn't be a security problem since
272 * PTRACE_MODE_REALCREDS implies that the caller explicitly
273 * used a syscall that requests access to another process
274 * (and not a filesystem syscall to procfs).
275 */
276 caller_uid = cred->uid;
277 caller_gid = cred->gid;
278 }
David Howellsc69e8d92008-11-14 10:39:19 +1100279 tcred = __task_cred(task);
Jann Horn969624b2016-01-20 15:00:04 -0800280 if (uid_eq(caller_uid, tcred->euid) &&
281 uid_eq(caller_uid, tcred->suid) &&
282 uid_eq(caller_uid, tcred->uid) &&
283 gid_eq(caller_gid, tcred->egid) &&
284 gid_eq(caller_gid, tcred->sgid) &&
285 gid_eq(caller_gid, tcred->gid))
Serge E. Hallyn8409cca2011-03-23 16:43:20 -0700286 goto ok;
Eric W. Biedermanc4a4d602011-11-16 23:15:31 -0800287 if (ptrace_has_cap(tcred->user_ns, mode))
Serge E. Hallyn8409cca2011-03-23 16:43:20 -0700288 goto ok;
289 rcu_read_unlock();
290 return -EPERM;
291ok:
David Howellsc69e8d92008-11-14 10:39:19 +1100292 rcu_read_unlock();
Jann Hornd774bd22019-05-29 13:31:57 +0200293 /*
294 * If a task drops privileges and becomes nondumpable (through a syscall
295 * like setresuid()) while we are trying to access it, we must ensure
296 * that the dumpability is read after the credentials; otherwise,
297 * we may be able to attach to a task that we shouldn't be able to
298 * attach to (as if the task had dropped privileges without becoming
299 * nondumpable).
300 * Pairs with a write barrier in commit_creds().
301 */
302 smp_rmb();
Eric W. Biederman03eed7a2016-10-13 21:23:16 -0500303 mm = task->mm;
304 if (mm &&
305 ((get_dumpable(mm) != SUID_DUMP_USER) &&
306 !ptrace_has_cap(mm->user_ns, mode)))
307 return -EPERM;
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700308
Jiri Kosina4a215a12018-09-25 14:38:18 +0200309 if (mode & PTRACE_MODE_SCHED)
310 return 0;
Ingo Molnar9e488582009-05-07 19:26:19 +1000311 return security_ptrace_access_check(task, mode);
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700312}
313
Jiri Kosina4a215a12018-09-25 14:38:18 +0200314bool ptrace_may_access_sched(struct task_struct *task, unsigned int mode)
315{
316 return __ptrace_may_access(task, mode | PTRACE_MODE_SCHED);
317}
318
Stephen Smalley006ebb42008-05-19 08:32:49 -0400319bool ptrace_may_access(struct task_struct *task, unsigned int mode)
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700320{
321 int err;
322 task_lock(task);
Stephen Smalley006ebb42008-05-19 08:32:49 -0400323 err = __ptrace_may_access(task, mode);
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700324 task_unlock(task);
Roland McGrath3a709702009-04-07 23:21:06 -0700325 return !err;
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700326}
327
Tejun Heo3544d722011-06-14 11:20:15 +0200328static int ptrace_attach(struct task_struct *task, long request,
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -0700329 unsigned long addr,
Tejun Heo3544d722011-06-14 11:20:15 +0200330 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331{
Tejun Heo3544d722011-06-14 11:20:15 +0200332 bool seize = (request == PTRACE_SEIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 int retval;
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700334
Tejun Heo3544d722011-06-14 11:20:15 +0200335 retval = -EIO;
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -0700336 if (seize) {
337 if (addr != 0)
338 goto out;
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -0700339 if (flags & ~(unsigned long)PTRACE_O_MASK)
340 goto out;
341 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
342 } else {
343 flags = PT_PTRACED;
344 }
Tejun Heo3544d722011-06-14 11:20:15 +0200345
Al Viroa5cb0132007-03-20 13:58:35 -0400346 audit_ptrace(task);
347
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 retval = -EPERM;
Oleg Nesterovb79b7ba2009-06-17 16:27:31 -0700349 if (unlikely(task->flags & PF_KTHREAD))
350 goto out;
Pavel Emelyanovbac0abd2007-10-18 23:40:18 -0700351 if (same_thread_group(task, current))
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700352 goto out;
353
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700354 /*
355 * Protect exec's credential calculations against our interference;
Denys Vlasenko86b6c1f2012-03-23 15:02:41 -0700356 * SUID, SGID and LSM creds get determined differently
David Howells5e751e92009-05-08 13:55:22 +0100357 * under ptrace.
David Howellsd84f4f92008-11-14 10:39:23 +1100358 */
Oleg Nesterov793285f2009-07-05 12:08:26 -0700359 retval = -ERESTARTNOINTR;
KOSAKI Motohiro9b1bf122010-10-27 15:34:08 -0700360 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
David Howellsd84f4f92008-11-14 10:39:23 +1100361 goto out;
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700362
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700363 task_lock(task);
Jann Horn969624b2016-01-20 15:00:04 -0800364 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700365 task_unlock(task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 if (retval)
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700367 goto unlock_creds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700369 write_lock_irq(&tasklist_lock);
Oleg Nesterovb79b7ba2009-06-17 16:27:31 -0700370 retval = -EPERM;
371 if (unlikely(task->exit_state))
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700372 goto unlock_tasklist;
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700373 if (task->ptrace)
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700374 goto unlock_tasklist;
Oleg Nesterovb79b7ba2009-06-17 16:27:31 -0700375
Tejun Heo3544d722011-06-14 11:20:15 +0200376 if (seize)
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -0700377 flags |= PT_SEIZED;
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -0700378 task->ptrace = flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379
Eric W. Biedermanc94bea22017-05-22 15:40:12 -0500380 ptrace_link(task, current);
Tejun Heo3544d722011-06-14 11:20:15 +0200381
382 /* SEIZE doesn't trap tracee on attach */
383 if (!seize)
384 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
Oleg Nesterovb79b7ba2009-06-17 16:27:31 -0700385
Tejun Heod79fdd62011-03-23 10:37:00 +0100386 spin_lock(&task->sighand->siglock);
387
388 /*
Tejun Heo73ddff22011-06-14 11:20:14 +0200389 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
Tejun Heod79fdd62011-03-23 10:37:00 +0100390 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
391 * will be cleared if the child completes the transition or any
392 * event which clears the group stop states happens. We'll wait
393 * for the transition to complete before returning from this
394 * function.
395 *
396 * This hides STOPPED -> RUNNING -> TRACED transition from the
397 * attaching thread but a different thread in the same group can
398 * still observe the transient RUNNING state. IOW, if another
399 * thread's WNOHANG wait(2) on the stopped tracee races against
400 * ATTACH, the wait(2) may fail due to the transient RUNNING.
401 *
402 * The following task_is_stopped() test is safe as both transitions
403 * in and out of STOPPED are protected by siglock.
404 */
Tejun Heo7dd3db52011-06-02 11:14:00 +0200405 if (task_is_stopped(task) &&
Tejun Heo73ddff22011-06-14 11:20:14 +0200406 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
Oleg Nesterov910ffdb2013-01-21 20:47:41 +0100407 signal_wake_up_state(task, __TASK_STOPPED);
Tejun Heod79fdd62011-03-23 10:37:00 +0100408
409 spin_unlock(&task->sighand->siglock);
410
Oleg Nesterovb79b7ba2009-06-17 16:27:31 -0700411 retval = 0;
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700412unlock_tasklist:
413 write_unlock_irq(&tasklist_lock);
414unlock_creds:
KOSAKI Motohiro9b1bf122010-10-27 15:34:08 -0700415 mutex_unlock(&task->signal->cred_guard_mutex);
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700416out:
Vladimir Zapolskiyf701e5b2011-07-15 20:45:18 +0300417 if (!retval) {
Tejun Heo62c124f2011-06-02 11:14:00 +0200418 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT,
NeilBrown74316202014-07-07 15:16:04 +1000419 TASK_UNINTERRUPTIBLE);
Vladimir Zapolskiyf701e5b2011-07-15 20:45:18 +0300420 proc_ptrace_connector(task, PTRACE_ATTACH);
421 }
422
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 return retval;
424}
425
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700426/**
427 * ptrace_traceme -- helper for PTRACE_TRACEME
428 *
429 * Performs checks and sets PT_PTRACED.
430 * Should be used by all ptrace implementations for PTRACE_TRACEME.
431 */
Linus Torvaldse3e89cc2011-03-04 09:23:30 -0800432static int ptrace_traceme(void)
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700433{
434 int ret = -EPERM;
435
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700436 write_lock_irq(&tasklist_lock);
437 /* Are we already being traced? */
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700438 if (!current->ptrace) {
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700439 ret = security_ptrace_traceme(current->parent);
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700440 /*
441 * Check PF_EXITING to ensure ->real_parent has not passed
442 * exit_ptrace(). Otherwise we don't report the error but
443 * pretend ->real_parent untraces us right after return.
444 */
445 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
446 current->ptrace = PT_PTRACED;
Eric W. Biedermanc94bea22017-05-22 15:40:12 -0500447 ptrace_link(current, current->real_parent);
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700448 }
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700449 }
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700450 write_unlock_irq(&tasklist_lock);
451
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700452 return ret;
453}
454
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700455/*
456 * Called with irqs disabled, returns true if childs should reap themselves.
457 */
458static int ignoring_children(struct sighand_struct *sigh)
459{
460 int ret;
461 spin_lock(&sigh->siglock);
462 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
463 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
464 spin_unlock(&sigh->siglock);
465 return ret;
466}
467
468/*
469 * Called with tasklist_lock held for writing.
470 * Unlink a traced task, and clean it up if it was a traced zombie.
471 * Return true if it needs to be reaped with release_task().
472 * (We can't call release_task() here because we already hold tasklist_lock.)
473 *
474 * If it's a zombie, our attachedness prevented normal parent notification
475 * or self-reaping. Do notification now if it would have happened earlier.
476 * If it should reap itself, return true.
477 *
Oleg Nesterova7f07652009-09-23 15:56:44 -0700478 * If it's our own child, there is no notification to do. But if our normal
479 * children self-reap, then this child was prevented by ptrace and we must
480 * reap it now, in that case we must also wake up sub-threads sleeping in
481 * do_wait().
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700482 */
483static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
484{
Oleg Nesterov9843a1e2011-06-22 23:08:53 +0200485 bool dead;
486
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700487 __ptrace_unlink(p);
488
Oleg Nesterov9843a1e2011-06-22 23:08:53 +0200489 if (p->exit_state != EXIT_ZOMBIE)
490 return false;
491
492 dead = !thread_group_leader(p);
493
494 if (!dead && thread_group_empty(p)) {
495 if (!same_thread_group(p->real_parent, tracer))
496 dead = do_notify_parent(p, p->exit_signal);
497 else if (ignoring_children(tracer->sighand)) {
498 __wake_up_parent(p, tracer);
Oleg Nesterov9843a1e2011-06-22 23:08:53 +0200499 dead = true;
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700500 }
501 }
Oleg Nesterov9843a1e2011-06-22 23:08:53 +0200502 /* Mark it as in the process of being reaped. */
503 if (dead)
504 p->exit_state = EXIT_DEAD;
505 return dead;
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700506}
507
Linus Torvaldse3e89cc2011-03-04 09:23:30 -0800508static int ptrace_detach(struct task_struct *child, unsigned int data)
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +0300509{
510 if (!valid_signal(data))
511 return -EIO;
512
513 /* Architecture-specific hardware disable .. */
514 ptrace_disable(child);
Roland McGrath7d941432007-09-05 03:05:56 -0700515 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +0300516
Oleg Nesterov95c3eb72009-04-02 16:58:11 -0700517 write_lock_irq(&tasklist_lock);
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700518 /*
Oleg Nesterov64a40962015-04-16 12:47:32 -0700519 * We rely on ptrace_freeze_traced(). It can't be killed and
520 * untraced by another thread, it can't be a zombie.
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700521 */
Oleg Nesterov64a40962015-04-16 12:47:32 -0700522 WARN_ON(!child->ptrace || child->exit_state);
523 /*
524 * tasklist_lock avoids the race with wait_task_stopped(), see
525 * the comment in ptrace_resume().
526 */
527 child->exit_code = data;
528 __ptrace_detach(current, child);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 write_unlock_irq(&tasklist_lock);
530
Vladimir Zapolskiyf701e5b2011-07-15 20:45:18 +0300531 proc_ptrace_connector(child, PTRACE_DETACH);
Oleg Nesterov45761452009-04-02 16:58:14 -0700532
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 return 0;
534}
535
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700536/*
Oleg Nesterovc7e49c12010-08-10 18:03:07 -0700537 * Detach all tasks we were using ptrace on. Called with tasklist held
Oleg Nesterov7c8bd232014-12-10 15:45:33 -0800538 * for writing.
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700539 */
Oleg Nesterov7c8bd232014-12-10 15:45:33 -0800540void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700541{
542 struct task_struct *p, *n;
Oleg Nesterovc7e49c12010-08-10 18:03:07 -0700543
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700544 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
Oleg Nesterov992fb6e2012-12-17 16:03:07 -0800545 if (unlikely(p->ptrace & PT_EXITKILL))
546 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
547
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700548 if (__ptrace_detach(tracer, p))
Oleg Nesterov7c8bd232014-12-10 15:45:33 -0800549 list_add(&p->ptrace_entry, dead);
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700550 }
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700551}
552
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
554{
555 int copied = 0;
556
557 while (len > 0) {
558 char buf[128];
559 int this_len, retval;
560
561 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
562 retval = access_process_vm(tsk, src, buf, this_len, 0);
563 if (!retval) {
564 if (copied)
565 break;
566 return -EIO;
567 }
568 if (copy_to_user(dst, buf, retval))
569 return -EFAULT;
570 copied += retval;
571 src += retval;
572 dst += retval;
Roland McGrath3a709702009-04-07 23:21:06 -0700573 len -= retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 }
575 return copied;
576}
577
578int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
579{
580 int copied = 0;
581
582 while (len > 0) {
583 char buf[128];
584 int this_len, retval;
585
586 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
587 if (copy_from_user(buf, src, this_len))
588 return -EFAULT;
589 retval = access_process_vm(tsk, dst, buf, this_len, 1);
590 if (!retval) {
591 if (copied)
592 break;
593 return -EIO;
594 }
595 copied += retval;
596 src += retval;
597 dst += retval;
Roland McGrath3a709702009-04-07 23:21:06 -0700598 len -= retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 }
600 return copied;
601}
602
Namhyung Kim4abf9862010-10-27 15:33:45 -0700603static int ptrace_setoptions(struct task_struct *child, unsigned long data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604{
Denys Vlasenko86b6c1f2012-03-23 15:02:41 -0700605 unsigned flags;
606
Denys Vlasenko8c5cf9e2012-03-23 15:02:40 -0700607 if (data & ~(unsigned long)PTRACE_O_MASK)
608 return -EINVAL;
609
Tycho Andersen13c4a902015-06-13 09:02:48 -0600610 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
611 if (!config_enabled(CONFIG_CHECKPOINT_RESTORE) ||
612 !config_enabled(CONFIG_SECCOMP))
613 return -EINVAL;
614
615 if (!capable(CAP_SYS_ADMIN))
616 return -EPERM;
617
618 if (seccomp_mode(&current->seccomp) != SECCOMP_MODE_DISABLED ||
619 current->ptrace & PT_SUSPEND_SECCOMP)
620 return -EPERM;
621 }
622
Denys Vlasenko86b6c1f2012-03-23 15:02:41 -0700623 /* Avoid intermediate state when all opts are cleared */
624 flags = child->ptrace;
625 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
626 flags |= (data << PT_OPT_FLAG_SHIFT);
627 child->ptrace = flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628
Denys Vlasenko8c5cf9e2012-03-23 15:02:40 -0700629 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630}
631
Roland McGrathe16b2782008-04-20 13:10:12 -0700632static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633{
Oleg Nesterove4961252009-06-17 16:27:36 -0700634 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 int error = -ESRCH;
636
Oleg Nesterove4961252009-06-17 16:27:36 -0700637 if (lock_task_sighand(child, &flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 if (likely(child->last_siginfo != NULL)) {
Roland McGrathe16b2782008-04-20 13:10:12 -0700640 *info = *child->last_siginfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 error = 0;
642 }
Oleg Nesterove4961252009-06-17 16:27:36 -0700643 unlock_task_sighand(child, &flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 return error;
646}
647
Roland McGrathe16b2782008-04-20 13:10:12 -0700648static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649{
Oleg Nesterove4961252009-06-17 16:27:36 -0700650 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 int error = -ESRCH;
652
Oleg Nesterove4961252009-06-17 16:27:36 -0700653 if (lock_task_sighand(child, &flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 if (likely(child->last_siginfo != NULL)) {
Roland McGrathe16b2782008-04-20 13:10:12 -0700656 *child->last_siginfo = *info;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 error = 0;
658 }
Oleg Nesterove4961252009-06-17 16:27:36 -0700659 unlock_task_sighand(child, &flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 return error;
662}
663
Andrey Vagin84c751b2013-04-30 15:27:59 -0700664static int ptrace_peek_siginfo(struct task_struct *child,
665 unsigned long addr,
666 unsigned long data)
667{
668 struct ptrace_peeksiginfo_args arg;
669 struct sigpending *pending;
670 struct sigqueue *q;
671 int ret, i;
672
673 ret = copy_from_user(&arg, (void __user *) addr,
674 sizeof(struct ptrace_peeksiginfo_args));
675 if (ret)
676 return -EFAULT;
677
678 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
679 return -EINVAL; /* unknown flags */
680
681 if (arg.nr < 0)
682 return -EINVAL;
683
Eric W. Biederman5aff00e2019-05-28 18:46:37 -0500684 /* Ensure arg.off fits in an unsigned long */
685 if (arg.off > ULONG_MAX)
686 return 0;
687
Andrey Vagin84c751b2013-04-30 15:27:59 -0700688 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
689 pending = &child->signal->shared_pending;
690 else
691 pending = &child->pending;
692
693 for (i = 0; i < arg.nr; ) {
694 siginfo_t info;
Eric W. Biederman5aff00e2019-05-28 18:46:37 -0500695 unsigned long off = arg.off + i;
696 bool found = false;
Andrey Vagin84c751b2013-04-30 15:27:59 -0700697
698 spin_lock_irq(&child->sighand->siglock);
699 list_for_each_entry(q, &pending->list, list) {
700 if (!off--) {
Eric W. Biederman5aff00e2019-05-28 18:46:37 -0500701 found = true;
Andrey Vagin84c751b2013-04-30 15:27:59 -0700702 copy_siginfo(&info, &q->info);
703 break;
704 }
705 }
706 spin_unlock_irq(&child->sighand->siglock);
707
Eric W. Biederman5aff00e2019-05-28 18:46:37 -0500708 if (!found) /* beyond the end of the list */
Andrey Vagin84c751b2013-04-30 15:27:59 -0700709 break;
710
711#ifdef CONFIG_COMPAT
712 if (unlikely(is_compat_task())) {
713 compat_siginfo_t __user *uinfo = compat_ptr(data);
714
Mathieu Desnoyers706b23b2013-06-28 09:49:46 -0400715 if (copy_siginfo_to_user32(uinfo, &info) ||
716 __put_user(info.si_code, &uinfo->si_code)) {
717 ret = -EFAULT;
718 break;
719 }
720
Andrey Vagin84c751b2013-04-30 15:27:59 -0700721 } else
722#endif
723 {
724 siginfo_t __user *uinfo = (siginfo_t __user *) data;
725
Mathieu Desnoyers706b23b2013-06-28 09:49:46 -0400726 if (copy_siginfo_to_user(uinfo, &info) ||
727 __put_user(info.si_code, &uinfo->si_code)) {
728 ret = -EFAULT;
729 break;
730 }
Andrey Vagin84c751b2013-04-30 15:27:59 -0700731 }
732
733 data += sizeof(siginfo_t);
734 i++;
735
736 if (signal_pending(current))
737 break;
738
739 cond_resched();
740 }
741
742 if (i > 0)
743 return i;
744
745 return ret;
746}
Roland McGrath36df29d2008-01-30 13:30:51 +0100747
748#ifdef PTRACE_SINGLESTEP
749#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
750#else
751#define is_singlestep(request) 0
752#endif
753
Roland McGrath5b88abb2008-01-30 13:30:53 +0100754#ifdef PTRACE_SINGLEBLOCK
755#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
756#else
757#define is_singleblock(request) 0
758#endif
759
Roland McGrath36df29d2008-01-30 13:30:51 +0100760#ifdef PTRACE_SYSEMU
761#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
762#else
763#define is_sysemu_singlestep(request) 0
764#endif
765
Namhyung Kim4abf9862010-10-27 15:33:45 -0700766static int ptrace_resume(struct task_struct *child, long request,
767 unsigned long data)
Roland McGrath36df29d2008-01-30 13:30:51 +0100768{
Oleg Nesterovb72c1862015-04-16 12:47:29 -0700769 bool need_siglock;
770
Roland McGrath36df29d2008-01-30 13:30:51 +0100771 if (!valid_signal(data))
772 return -EIO;
773
774 if (request == PTRACE_SYSCALL)
775 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
776 else
777 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
778
779#ifdef TIF_SYSCALL_EMU
780 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
781 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
782 else
783 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
784#endif
785
Roland McGrath5b88abb2008-01-30 13:30:53 +0100786 if (is_singleblock(request)) {
787 if (unlikely(!arch_has_block_step()))
788 return -EIO;
789 user_enable_block_step(child);
790 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
Roland McGrath36df29d2008-01-30 13:30:51 +0100791 if (unlikely(!arch_has_single_step()))
792 return -EIO;
793 user_enable_single_step(child);
Roland McGrath3a709702009-04-07 23:21:06 -0700794 } else {
Roland McGrath36df29d2008-01-30 13:30:51 +0100795 user_disable_single_step(child);
Roland McGrath3a709702009-04-07 23:21:06 -0700796 }
Roland McGrath36df29d2008-01-30 13:30:51 +0100797
Oleg Nesterovb72c1862015-04-16 12:47:29 -0700798 /*
799 * Change ->exit_code and ->state under siglock to avoid the race
800 * with wait_task_stopped() in between; a non-zero ->exit_code will
801 * wrongly look like another report from tracee.
802 *
803 * Note that we need siglock even if ->exit_code == data and/or this
804 * status was not reported yet, the new status must not be cleared by
805 * wait_task_stopped() after resume.
806 *
807 * If data == 0 we do not care if wait_task_stopped() reports the old
808 * status and clears the code too; this can't race with the tracee, it
809 * takes siglock after resume.
810 */
811 need_siglock = data && !thread_group_empty(current);
812 if (need_siglock)
813 spin_lock_irq(&child->sighand->siglock);
Roland McGrath36df29d2008-01-30 13:30:51 +0100814 child->exit_code = data;
Oleg Nesterov0666fb52011-05-25 19:20:21 +0200815 wake_up_state(child, __TASK_TRACED);
Oleg Nesterovb72c1862015-04-16 12:47:29 -0700816 if (need_siglock)
817 spin_unlock_irq(&child->sighand->siglock);
Roland McGrath36df29d2008-01-30 13:30:51 +0100818
819 return 0;
820}
821
Suresh Siddha2225a122010-02-11 11:51:00 -0800822#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
823
824static const struct user_regset *
825find_regset(const struct user_regset_view *view, unsigned int type)
826{
827 const struct user_regset *regset;
828 int n;
829
830 for (n = 0; n < view->n; ++n) {
831 regset = view->regsets + n;
832 if (regset->core_note_type == type)
833 return regset;
834 }
835
836 return NULL;
837}
838
839static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
840 struct iovec *kiov)
841{
842 const struct user_regset_view *view = task_user_regset_view(task);
843 const struct user_regset *regset = find_regset(view, type);
844 int regset_no;
845
846 if (!regset || (kiov->iov_len % regset->size) != 0)
Suresh Siddhac6a0dd72010-02-22 14:51:32 -0800847 return -EINVAL;
Suresh Siddha2225a122010-02-11 11:51:00 -0800848
849 regset_no = regset - view->regsets;
850 kiov->iov_len = min(kiov->iov_len,
851 (__kernel_size_t) (regset->n * regset->size));
852
853 if (req == PTRACE_GETREGSET)
854 return copy_regset_to_user(task, view, regset_no, 0,
855 kiov->iov_len, kiov->iov_base);
856 else
857 return copy_regset_from_user(task, view, regset_no, 0,
858 kiov->iov_len, kiov->iov_base);
859}
860
Josh Stonee8440c12013-01-13 19:03:34 +0100861/*
862 * This is declared in linux/regset.h and defined in machine-dependent
863 * code. We put the export here, near the primary machine-neutral use,
864 * to ensure no machine forgets it.
865 */
866EXPORT_SYMBOL_GPL(task_user_regset_view);
Suresh Siddha2225a122010-02-11 11:51:00 -0800867#endif
868
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869int ptrace_request(struct task_struct *child, long request,
Namhyung Kim4abf9862010-10-27 15:33:45 -0700870 unsigned long addr, unsigned long data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871{
Tejun Heofca26f22011-06-14 11:20:16 +0200872 bool seized = child->ptrace & PT_SEIZED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 int ret = -EIO;
Tejun Heo544b2c92011-06-14 11:20:18 +0200874 siginfo_t siginfo, *si;
Namhyung Kim9fed81d2010-10-27 15:33:46 -0700875 void __user *datavp = (void __user *) data;
876 unsigned long __user *datalp = datavp;
Tejun Heofca26f22011-06-14 11:20:16 +0200877 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878
879 switch (request) {
Roland McGrath16c3e382008-01-30 13:31:47 +0100880 case PTRACE_PEEKTEXT:
881 case PTRACE_PEEKDATA:
882 return generic_ptrace_peekdata(child, addr, data);
883 case PTRACE_POKETEXT:
884 case PTRACE_POKEDATA:
885 return generic_ptrace_pokedata(child, addr, data);
886
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887#ifdef PTRACE_OLDSETOPTIONS
888 case PTRACE_OLDSETOPTIONS:
889#endif
890 case PTRACE_SETOPTIONS:
891 ret = ptrace_setoptions(child, data);
892 break;
893 case PTRACE_GETEVENTMSG:
Namhyung Kim9fed81d2010-10-27 15:33:46 -0700894 ret = put_user(child->ptrace_message, datalp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 break;
Roland McGrathe16b2782008-04-20 13:10:12 -0700896
Andrey Vagin84c751b2013-04-30 15:27:59 -0700897 case PTRACE_PEEKSIGINFO:
898 ret = ptrace_peek_siginfo(child, addr, data);
899 break;
900
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 case PTRACE_GETSIGINFO:
Roland McGrathe16b2782008-04-20 13:10:12 -0700902 ret = ptrace_getsiginfo(child, &siginfo);
903 if (!ret)
Namhyung Kim9fed81d2010-10-27 15:33:46 -0700904 ret = copy_siginfo_to_user(datavp, &siginfo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 break;
Roland McGrathe16b2782008-04-20 13:10:12 -0700906
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 case PTRACE_SETSIGINFO:
Namhyung Kim9fed81d2010-10-27 15:33:46 -0700908 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
Roland McGrathe16b2782008-04-20 13:10:12 -0700909 ret = -EFAULT;
910 else
911 ret = ptrace_setsiginfo(child, &siginfo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 break;
Roland McGrathe16b2782008-04-20 13:10:12 -0700913
Andrey Vagin29000ca2013-07-03 15:08:12 -0700914 case PTRACE_GETSIGMASK:
915 if (addr != sizeof(sigset_t)) {
916 ret = -EINVAL;
917 break;
918 }
919
920 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
921 ret = -EFAULT;
922 else
923 ret = 0;
924
925 break;
926
927 case PTRACE_SETSIGMASK: {
928 sigset_t new_set;
929
930 if (addr != sizeof(sigset_t)) {
931 ret = -EINVAL;
932 break;
933 }
934
935 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
936 ret = -EFAULT;
937 break;
938 }
939
940 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
941
942 /*
943 * Every thread does recalc_sigpending() after resume, so
944 * retarget_shared_pending() and recalc_sigpending() are not
945 * called here.
946 */
947 spin_lock_irq(&child->sighand->siglock);
948 child->blocked = new_set;
949 spin_unlock_irq(&child->sighand->siglock);
950
951 ret = 0;
952 break;
953 }
954
Tejun Heofca26f22011-06-14 11:20:16 +0200955 case PTRACE_INTERRUPT:
956 /*
957 * Stop tracee without any side-effect on signal or job
958 * control. At least one trap is guaranteed to happen
959 * after this request. If @child is already trapped, the
960 * current trap is not disturbed and another trap will
961 * happen after the current trap is ended with PTRACE_CONT.
962 *
963 * The actual trap might not be PTRACE_EVENT_STOP trap but
964 * the pending condition is cleared regardless.
965 */
966 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
967 break;
968
Tejun Heo544b2c92011-06-14 11:20:18 +0200969 /*
970 * INTERRUPT doesn't disturb existing trap sans one
971 * exception. If ptracer issued LISTEN for the current
972 * STOP, this INTERRUPT should clear LISTEN and re-trap
973 * tracee into STOP.
974 */
Tejun Heofca26f22011-06-14 11:20:16 +0200975 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
Oleg Nesterov910ffdb2013-01-21 20:47:41 +0100976 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
Tejun Heo544b2c92011-06-14 11:20:18 +0200977
978 unlock_task_sighand(child, &flags);
979 ret = 0;
980 break;
981
982 case PTRACE_LISTEN:
983 /*
984 * Listen for events. Tracee must be in STOP. It's not
985 * resumed per-se but is not considered to be in TRACED by
986 * wait(2) or ptrace(2). If an async event (e.g. group
987 * stop state change) happens, tracee will enter STOP trap
988 * again. Alternatively, ptracer can issue INTERRUPT to
989 * finish listening and re-trap tracee into STOP.
990 */
991 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
992 break;
993
994 si = child->last_siginfo;
Oleg Nesterovf9d81f62011-09-25 19:46:22 +0200995 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
996 child->jobctl |= JOBCTL_LISTENING;
997 /*
998 * If NOTIFY is set, it means event happened between
999 * start of this trap and now. Trigger re-trap.
1000 */
1001 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
Oleg Nesterov910ffdb2013-01-21 20:47:41 +01001002 ptrace_signal_wake_up(child, true);
Oleg Nesterovf9d81f62011-09-25 19:46:22 +02001003 ret = 0;
1004 }
Tejun Heofca26f22011-06-14 11:20:16 +02001005 unlock_task_sighand(child, &flags);
Tejun Heofca26f22011-06-14 11:20:16 +02001006 break;
1007
Alexey Dobriyan1bcf5482007-10-16 01:23:45 -07001008 case PTRACE_DETACH: /* detach a process that was attached. */
1009 ret = ptrace_detach(child, data);
1010 break;
Roland McGrath36df29d2008-01-30 13:30:51 +01001011
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001012#ifdef CONFIG_BINFMT_ELF_FDPIC
1013 case PTRACE_GETFDPIC: {
Oleg Nesterove0129ef2010-05-26 14:42:53 -07001014 struct mm_struct *mm = get_task_mm(child);
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001015 unsigned long tmp = 0;
1016
Oleg Nesterove0129ef2010-05-26 14:42:53 -07001017 ret = -ESRCH;
1018 if (!mm)
1019 break;
1020
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001021 switch (addr) {
1022 case PTRACE_GETFDPIC_EXEC:
Oleg Nesterove0129ef2010-05-26 14:42:53 -07001023 tmp = mm->context.exec_fdpic_loadmap;
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001024 break;
1025 case PTRACE_GETFDPIC_INTERP:
Oleg Nesterove0129ef2010-05-26 14:42:53 -07001026 tmp = mm->context.interp_fdpic_loadmap;
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001027 break;
1028 default:
1029 break;
1030 }
Oleg Nesterove0129ef2010-05-26 14:42:53 -07001031 mmput(mm);
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001032
Namhyung Kim9fed81d2010-10-27 15:33:46 -07001033 ret = put_user(tmp, datalp);
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001034 break;
1035 }
1036#endif
1037
Roland McGrath36df29d2008-01-30 13:30:51 +01001038#ifdef PTRACE_SINGLESTEP
1039 case PTRACE_SINGLESTEP:
1040#endif
Roland McGrath5b88abb2008-01-30 13:30:53 +01001041#ifdef PTRACE_SINGLEBLOCK
1042 case PTRACE_SINGLEBLOCK:
1043#endif
Roland McGrath36df29d2008-01-30 13:30:51 +01001044#ifdef PTRACE_SYSEMU
1045 case PTRACE_SYSEMU:
1046 case PTRACE_SYSEMU_SINGLESTEP:
1047#endif
1048 case PTRACE_SYSCALL:
1049 case PTRACE_CONT:
1050 return ptrace_resume(child, request, data);
1051
1052 case PTRACE_KILL:
1053 if (child->exit_state) /* already dead */
1054 return 0;
1055 return ptrace_resume(child, request, SIGKILL);
1056
Suresh Siddha2225a122010-02-11 11:51:00 -08001057#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1058 case PTRACE_GETREGSET:
Andrey Vagin29000ca2013-07-03 15:08:12 -07001059 case PTRACE_SETREGSET: {
Suresh Siddha2225a122010-02-11 11:51:00 -08001060 struct iovec kiov;
Namhyung Kim9fed81d2010-10-27 15:33:46 -07001061 struct iovec __user *uiov = datavp;
Suresh Siddha2225a122010-02-11 11:51:00 -08001062
1063 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1064 return -EFAULT;
1065
1066 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1067 __get_user(kiov.iov_len, &uiov->iov_len))
1068 return -EFAULT;
1069
1070 ret = ptrace_regset(child, request, addr, &kiov);
1071 if (!ret)
1072 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1073 break;
1074 }
1075#endif
Tycho Andersenf8e529e2015-10-27 09:23:59 +09001076
1077 case PTRACE_SECCOMP_GET_FILTER:
1078 ret = seccomp_get_filter(child, addr, datavp);
1079 break;
1080
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 default:
1082 break;
1083 }
1084
1085 return ret;
1086}
Christoph Hellwig481bed42005-11-07 00:59:47 -08001087
Oleg Nesterov8053bdd2009-06-17 16:27:34 -07001088static struct task_struct *ptrace_get_task_struct(pid_t pid)
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -08001089{
1090 struct task_struct *child;
Christoph Hellwig481bed42005-11-07 00:59:47 -08001091
Oleg Nesterov8053bdd2009-06-17 16:27:34 -07001092 rcu_read_lock();
Pavel Emelyanov228ebcb2007-10-18 23:40:16 -07001093 child = find_task_by_vpid(pid);
Christoph Hellwig481bed42005-11-07 00:59:47 -08001094 if (child)
1095 get_task_struct(child);
Oleg Nesterov8053bdd2009-06-17 16:27:34 -07001096 rcu_read_unlock();
Sukadev Bhattiproluf400e192006-09-29 02:00:07 -07001097
Christoph Hellwig481bed42005-11-07 00:59:47 -08001098 if (!child)
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -08001099 return ERR_PTR(-ESRCH);
1100 return child;
Christoph Hellwig481bed42005-11-07 00:59:47 -08001101}
1102
Christoph Hellwig0ac15552007-10-16 01:26:37 -07001103#ifndef arch_ptrace_attach
1104#define arch_ptrace_attach(child) do { } while (0)
1105#endif
1106
Namhyung Kim4abf9862010-10-27 15:33:45 -07001107SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1108 unsigned long, data)
Christoph Hellwig481bed42005-11-07 00:59:47 -08001109{
1110 struct task_struct *child;
1111 long ret;
1112
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -08001113 if (request == PTRACE_TRACEME) {
1114 ret = ptrace_traceme();
Haavard Skinnemoen6ea6dd92007-11-27 13:02:40 +01001115 if (!ret)
1116 arch_ptrace_attach(current);
Christoph Hellwig481bed42005-11-07 00:59:47 -08001117 goto out;
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -08001118 }
1119
1120 child = ptrace_get_task_struct(pid);
1121 if (IS_ERR(child)) {
1122 ret = PTR_ERR(child);
1123 goto out;
1124 }
Christoph Hellwig481bed42005-11-07 00:59:47 -08001125
Tejun Heo3544d722011-06-14 11:20:15 +02001126 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -07001127 ret = ptrace_attach(child, request, addr, data);
Christoph Hellwig0ac15552007-10-16 01:26:37 -07001128 /*
1129 * Some architectures need to do book-keeping after
1130 * a ptrace attach.
1131 */
1132 if (!ret)
1133 arch_ptrace_attach(child);
Christoph Hellwig005f18d2005-11-13 16:06:33 -08001134 goto out_put_task_struct;
Christoph Hellwig481bed42005-11-07 00:59:47 -08001135 }
1136
Tejun Heofca26f22011-06-14 11:20:16 +02001137 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1138 request == PTRACE_INTERRUPT);
Christoph Hellwig481bed42005-11-07 00:59:47 -08001139 if (ret < 0)
1140 goto out_put_task_struct;
1141
1142 ret = arch_ptrace(child, request, addr, data);
Oleg Nesterov9899d112013-01-21 20:48:00 +01001143 if (ret || request != PTRACE_DETACH)
1144 ptrace_unfreeze_traced(child);
Christoph Hellwig481bed42005-11-07 00:59:47 -08001145
1146 out_put_task_struct:
1147 put_task_struct(child);
1148 out:
Christoph Hellwig481bed42005-11-07 00:59:47 -08001149 return ret;
1150}
Alexey Dobriyan76647322007-07-17 04:03:43 -07001151
Namhyung Kim4abf9862010-10-27 15:33:45 -07001152int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1153 unsigned long data)
Alexey Dobriyan76647322007-07-17 04:03:43 -07001154{
1155 unsigned long tmp;
1156 int copied;
1157
1158 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
1159 if (copied != sizeof(tmp))
1160 return -EIO;
1161 return put_user(tmp, (unsigned long __user *)data);
1162}
Alexey Dobriyanf284ce72007-07-17 04:03:44 -07001163
Namhyung Kim4abf9862010-10-27 15:33:45 -07001164int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1165 unsigned long data)
Alexey Dobriyanf284ce72007-07-17 04:03:44 -07001166{
1167 int copied;
1168
1169 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
1170 return (copied == sizeof(data)) ? 0 : -EIO;
1171}
Roland McGrath032d82d2008-01-30 13:31:47 +01001172
Christoph Hellwig96b89362008-11-25 08:10:03 +01001173#if defined CONFIG_COMPAT
Roland McGrath032d82d2008-01-30 13:31:47 +01001174
1175int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1176 compat_ulong_t addr, compat_ulong_t data)
1177{
1178 compat_ulong_t __user *datap = compat_ptr(data);
1179 compat_ulong_t word;
Roland McGrathe16b2782008-04-20 13:10:12 -07001180 siginfo_t siginfo;
Roland McGrath032d82d2008-01-30 13:31:47 +01001181 int ret;
1182
1183 switch (request) {
1184 case PTRACE_PEEKTEXT:
1185 case PTRACE_PEEKDATA:
1186 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
1187 if (ret != sizeof(word))
1188 ret = -EIO;
1189 else
1190 ret = put_user(word, datap);
1191 break;
1192
1193 case PTRACE_POKETEXT:
1194 case PTRACE_POKEDATA:
1195 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
1196 ret = (ret != sizeof(data) ? -EIO : 0);
1197 break;
1198
1199 case PTRACE_GETEVENTMSG:
1200 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1201 break;
1202
Roland McGrathe16b2782008-04-20 13:10:12 -07001203 case PTRACE_GETSIGINFO:
1204 ret = ptrace_getsiginfo(child, &siginfo);
1205 if (!ret)
1206 ret = copy_siginfo_to_user32(
1207 (struct compat_siginfo __user *) datap,
1208 &siginfo);
1209 break;
1210
1211 case PTRACE_SETSIGINFO:
1212 memset(&siginfo, 0, sizeof siginfo);
1213 if (copy_siginfo_from_user32(
1214 &siginfo, (struct compat_siginfo __user *) datap))
1215 ret = -EFAULT;
1216 else
1217 ret = ptrace_setsiginfo(child, &siginfo);
1218 break;
Suresh Siddha2225a122010-02-11 11:51:00 -08001219#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1220 case PTRACE_GETREGSET:
1221 case PTRACE_SETREGSET:
1222 {
1223 struct iovec kiov;
1224 struct compat_iovec __user *uiov =
1225 (struct compat_iovec __user *) datap;
1226 compat_uptr_t ptr;
1227 compat_size_t len;
1228
1229 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1230 return -EFAULT;
1231
1232 if (__get_user(ptr, &uiov->iov_base) ||
1233 __get_user(len, &uiov->iov_len))
1234 return -EFAULT;
1235
1236 kiov.iov_base = compat_ptr(ptr);
1237 kiov.iov_len = len;
1238
1239 ret = ptrace_regset(child, request, addr, &kiov);
1240 if (!ret)
1241 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1242 break;
1243 }
1244#endif
Roland McGrathe16b2782008-04-20 13:10:12 -07001245
Roland McGrath032d82d2008-01-30 13:31:47 +01001246 default:
1247 ret = ptrace_request(child, request, addr, data);
1248 }
1249
1250 return ret;
1251}
Roland McGrathc269f192008-01-30 13:31:48 +01001252
Heiko Carstens62a6fa92014-03-03 16:11:13 +01001253COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1254 compat_long_t, addr, compat_long_t, data)
Roland McGrathc269f192008-01-30 13:31:48 +01001255{
1256 struct task_struct *child;
1257 long ret;
1258
Roland McGrathc269f192008-01-30 13:31:48 +01001259 if (request == PTRACE_TRACEME) {
1260 ret = ptrace_traceme();
1261 goto out;
1262 }
1263
1264 child = ptrace_get_task_struct(pid);
1265 if (IS_ERR(child)) {
1266 ret = PTR_ERR(child);
1267 goto out;
1268 }
1269
Tejun Heo3544d722011-06-14 11:20:15 +02001270 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -07001271 ret = ptrace_attach(child, request, addr, data);
Roland McGrathc269f192008-01-30 13:31:48 +01001272 /*
1273 * Some architectures need to do book-keeping after
1274 * a ptrace attach.
1275 */
1276 if (!ret)
1277 arch_ptrace_attach(child);
1278 goto out_put_task_struct;
1279 }
1280
Tejun Heofca26f22011-06-14 11:20:16 +02001281 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1282 request == PTRACE_INTERRUPT);
Oleg Nesterov9899d112013-01-21 20:48:00 +01001283 if (!ret) {
Roland McGrathc269f192008-01-30 13:31:48 +01001284 ret = compat_arch_ptrace(child, request, addr, data);
Oleg Nesterov9899d112013-01-21 20:48:00 +01001285 if (ret || request != PTRACE_DETACH)
1286 ptrace_unfreeze_traced(child);
1287 }
Roland McGrathc269f192008-01-30 13:31:48 +01001288
1289 out_put_task_struct:
1290 put_task_struct(child);
1291 out:
Roland McGrathc269f192008-01-30 13:31:48 +01001292 return ret;
1293}
Christoph Hellwig96b89362008-11-25 08:10:03 +01001294#endif /* CONFIG_COMPAT */