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Thomas Gleixner457c8992019-05-19 13:08:55 +01001// SPDX-License-Identifier: GPL-2.0-only
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * linux/kernel/ptrace.c
4 *
5 * (C) Copyright 1999 Linus Torvalds
6 *
7 * Common interfaces for "ptrace()" which we do not want
8 * to continually duplicate across every architecture.
9 */
10
Randy.Dunlapc59ede72006-01-11 12:17:46 -080011#include <linux/capability.h>
Paul Gortmaker9984de12011-05-23 14:51:41 -040012#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/sched.h>
Ingo Molnar6e84f312017-02-08 18:51:29 +010014#include <linux/sched/mm.h>
Ingo Molnarf7ccbae2017-02-08 18:51:30 +010015#include <linux/sched/coredump.h>
Ingo Molnar29930022017-02-08 18:51:36 +010016#include <linux/sched/task.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/errno.h>
18#include <linux/mm.h>
19#include <linux/highmem.h>
20#include <linux/pagemap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/ptrace.h>
22#include <linux/security.h>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070023#include <linux/signal.h>
Kent Overstreeta27bb332013-05-07 16:19:08 -070024#include <linux/uio.h>
Al Viroa5cb0132007-03-20 13:58:35 -040025#include <linux/audit.h>
Pavel Emelyanovb4888932007-10-18 23:40:14 -070026#include <linux/pid_namespace.h>
Adrian Bunkf17d30a2008-02-06 01:36:44 -080027#include <linux/syscalls.h>
Roland McGrath3a709702009-04-07 23:21:06 -070028#include <linux/uaccess.h>
Suresh Siddha2225a122010-02-11 11:51:00 -080029#include <linux/regset.h>
Frederic Weisbeckerbf26c012011-04-07 16:53:20 +020030#include <linux/hw_breakpoint.h>
Vladimir Zapolskiyf701e5b2011-07-15 20:45:18 +030031#include <linux/cn_proc.h>
Andrey Vagin84c751b2013-04-30 15:27:59 -070032#include <linux/compat.h>
Andrei Vaginfcfc2aa02019-03-28 20:44:13 -070033#include <linux/sched/signal.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Elvira Khabirova201766a2019-07-16 16:29:42 -070035#include <asm/syscall.h> /* for syscall_get_* */
36
Eric W. Biederman84d77d32016-11-22 12:06:50 -060037/*
38 * Access another process' address space via ptrace.
39 * Source/target buffer must be kernel space,
40 * Do not walk the page table directly, use get_user_pages
41 */
42int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
43 void *buf, int len, unsigned int gup_flags)
44{
45 struct mm_struct *mm;
46 int ret;
47
48 mm = get_task_mm(tsk);
49 if (!mm)
50 return 0;
51
52 if (!tsk->ptrace ||
53 (current != tsk->parent) ||
54 ((get_dumpable(mm) != SUID_DUMP_USER) &&
55 !ptracer_capable(tsk, mm->user_ns))) {
56 mmput(mm);
57 return 0;
58 }
59
John Hubbardd3f5ffc2020-12-14 19:07:45 -080060 ret = __access_remote_vm(mm, addr, buf, len, gup_flags);
Eric W. Biederman84d77d32016-11-22 12:06:50 -060061 mmput(mm);
62
63 return ret;
64}
65
Markus Metzgerbf53de92008-12-19 15:10:24 +010066
Eric W. Biedermanc70d9d82017-05-22 15:40:12 -050067void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
68 const struct cred *ptracer_cred)
69{
70 BUG_ON(!list_empty(&child->ptrace_entry));
71 list_add(&child->ptrace_entry, &new_parent->ptraced);
72 child->parent = new_parent;
73 child->ptracer_cred = get_cred(ptracer_cred);
74}
75
Markus Metzgerbf53de92008-12-19 15:10:24 +010076/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 * ptrace a task: make the debugger its new parent and
78 * move it to the ptrace list.
79 *
80 * Must be called with the tasklist lock write-held.
81 */
Eric W. Biedermanc70d9d82017-05-22 15:40:12 -050082static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -070083{
Jann Horn6994eef2019-07-04 17:32:23 +020084 __ptrace_link(child, new_parent, current_cred());
Linus Torvalds1da177e2005-04-16 15:20:36 -070085}
Roland McGrath3a709702009-04-07 23:21:06 -070086
Tejun Heoe3bd0582011-03-23 10:37:01 +010087/**
88 * __ptrace_unlink - unlink ptracee and restore its execution state
89 * @child: ptracee to be unlinked
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 *
Tejun Heo0e9f0a42011-03-23 10:37:01 +010091 * Remove @child from the ptrace list, move it back to the original parent,
92 * and restore the execution state so that it conforms to the group stop
93 * state.
94 *
95 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
96 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
97 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
98 * If the ptracer is exiting, the ptracee can be in any state.
99 *
100 * After detach, the ptracee should be in a state which conforms to the
101 * group stop. If the group is stopped or in the process of stopping, the
102 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
103 * up from TASK_TRACED.
104 *
105 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
106 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
107 * to but in the opposite direction of what happens while attaching to a
108 * stopped task. However, in this direction, the intermediate RUNNING
109 * state is not hidden even from the current ptracer and if it immediately
110 * re-attaches and performs a WNOHANG wait(2), it may fail.
Tejun Heoe3bd0582011-03-23 10:37:01 +0100111 *
112 * CONTEXT:
113 * write_lock_irq(tasklist_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 */
Ingo Molnar36c8b582006-07-03 00:25:41 -0700115void __ptrace_unlink(struct task_struct *child)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116{
Eric W. Biederman64b875f2016-11-14 18:48:07 -0600117 const struct cred *old_cred;
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +0300118 BUG_ON(!child->ptrace);
119
Gabriel Krisman Bertazi64c19ba2020-11-16 12:42:02 -0500120 clear_task_syscall_work(child, SYSCALL_TRACE);
Gabriel Krisman Bertazi64eb35f2020-11-16 12:42:03 -0500121#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
122 clear_task_syscall_work(child, SYSCALL_EMU);
Sudeep Holla15532fd2019-05-23 10:06:15 +0100123#endif
Ales Novak0a5bf402016-10-11 13:53:46 -0700124
Roland McGrathf4700212008-03-24 18:36:23 -0700125 child->parent = child->real_parent;
126 list_del_init(&child->ptrace_entry);
Eric W. Biederman64b875f2016-11-14 18:48:07 -0600127 old_cred = child->ptracer_cred;
128 child->ptracer_cred = NULL;
129 put_cred(old_cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 spin_lock(&child->sighand->siglock);
Oleg Nesterov1333ab02016-03-22 14:25:33 -0700132 child->ptrace = 0;
Tejun Heo0e9f0a42011-03-23 10:37:01 +0100133 /*
Tejun Heo73ddff22011-06-14 11:20:14 +0200134 * Clear all pending traps and TRAPPING. TRAPPING should be
135 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
136 */
137 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
138 task_clear_jobctl_trapping(child);
139
140 /*
Tejun Heoa8f072c2011-06-02 11:13:59 +0200141 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
Tejun Heo0e9f0a42011-03-23 10:37:01 +0100142 * @child isn't dead.
143 */
144 if (!(child->flags & PF_EXITING) &&
145 (child->signal->flags & SIGNAL_STOP_STOPPED ||
Oleg Nesterov8a889512012-01-04 17:29:20 +0100146 child->signal->group_stop_count)) {
Tejun Heoa8f072c2011-06-02 11:13:59 +0200147 child->jobctl |= JOBCTL_STOP_PENDING;
Tejun Heo0e9f0a42011-03-23 10:37:01 +0100148
Oleg Nesterov8a889512012-01-04 17:29:20 +0100149 /*
150 * This is only possible if this thread was cloned by the
151 * traced task running in the stopped group, set the signal
152 * for the future reports.
153 * FIXME: we should change ptrace_init_task() to handle this
154 * case.
155 */
156 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
157 child->jobctl |= SIGSTOP;
158 }
159
Tejun Heo0e9f0a42011-03-23 10:37:01 +0100160 /*
161 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
162 * @child in the butt. Note that @resume should be used iff @child
163 * is in TASK_TRACED; otherwise, we might unduly disrupt
164 * TASK_KILLABLE sleeps.
165 */
Tejun Heoa8f072c2011-06-02 11:13:59 +0200166 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
Oleg Nesterov910ffdb12013-01-21 20:47:41 +0100167 ptrace_signal_wake_up(child, true);
Tejun Heo0e9f0a42011-03-23 10:37:01 +0100168
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 spin_unlock(&child->sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170}
171
Oleg Nesterov9899d112013-01-21 20:48:00 +0100172/* Ensure that nothing can wake it up, even SIGKILL */
173static bool ptrace_freeze_traced(struct task_struct *task)
174{
175 bool ret = false;
176
177 /* Lockless, nobody but us can set this flag */
178 if (task->jobctl & JOBCTL_LISTENING)
179 return ret;
180
181 spin_lock_irq(&task->sighand->siglock);
182 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
183 task->state = __TASK_TRACED;
184 ret = true;
185 }
186 spin_unlock_irq(&task->sighand->siglock);
187
188 return ret;
189}
190
191static void ptrace_unfreeze_traced(struct task_struct *task)
192{
193 if (task->state != __TASK_TRACED)
194 return;
195
196 WARN_ON(!task->ptrace || task->parent != current);
197
bsegall@google.com5402e972017-04-07 16:04:51 -0700198 /*
199 * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
200 * Recheck state under the lock to close this race.
201 */
Oleg Nesterov9899d112013-01-21 20:48:00 +0100202 spin_lock_irq(&task->sighand->siglock);
bsegall@google.com5402e972017-04-07 16:04:51 -0700203 if (task->state == __TASK_TRACED) {
204 if (__fatal_signal_pending(task))
205 wake_up_state(task, __TASK_TRACED);
206 else
207 task->state = TASK_TRACED;
208 }
Oleg Nesterov9899d112013-01-21 20:48:00 +0100209 spin_unlock_irq(&task->sighand->siglock);
210}
211
Tejun Heo755e2762011-06-02 11:13:59 +0200212/**
213 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
214 * @child: ptracee to check for
215 * @ignore_state: don't check whether @child is currently %TASK_TRACED
216 *
217 * Check whether @child is being ptraced by %current and ready for further
218 * ptrace operations. If @ignore_state is %false, @child also should be in
219 * %TASK_TRACED state and on return the child is guaranteed to be traced
220 * and not executing. If @ignore_state is %true, @child can be in any
221 * state.
222 *
223 * CONTEXT:
224 * Grabs and releases tasklist_lock and @child->sighand->siglock.
225 *
226 * RETURNS:
227 * 0 on success, -ESRCH if %child is not ready.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 */
Oleg Nesterovedea0d02013-01-20 20:25:47 +0100229static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230{
231 int ret = -ESRCH;
232
233 /*
234 * We take the read lock around doing both checks to close a
235 * possible race where someone else was tracing our child and
236 * detached between these two checks. After this locked check,
237 * we are sure that this is our traced child and that can only
238 * be changed by us so it's not changing right after this.
239 */
240 read_lock(&tasklist_lock);
Oleg Nesterov9899d112013-01-21 20:48:00 +0100241 if (child->ptrace && child->parent == current) {
242 WARN_ON(child->state == __TASK_TRACED);
Oleg Nesterovc0c0b642008-02-08 04:19:00 -0800243 /*
244 * child->sighand can't be NULL, release_task()
245 * does ptrace_unlink() before __exit_signal().
246 */
Oleg Nesterov9899d112013-01-21 20:48:00 +0100247 if (ignore_state || ptrace_freeze_traced(child))
Oleg Nesterov321fb562011-04-01 20:13:01 +0200248 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 }
250 read_unlock(&tasklist_lock);
251
Oleg Nesterov9899d112013-01-21 20:48:00 +0100252 if (!ret && !ignore_state) {
253 if (!wait_task_inactive(child, __TASK_TRACED)) {
254 /*
255 * This can only happen if may_ptrace_stop() fails and
256 * ptrace_stop() changes ->state back to TASK_RUNNING,
257 * so we should not worry about leaking __TASK_TRACED.
258 */
259 WARN_ON(child->state == __TASK_TRACED);
260 ret = -ESRCH;
261 }
262 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 return ret;
265}
266
Mickaël Salaüncf237052020-10-30 13:38:48 +0100267static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
Eric Paris69f594a2012-01-03 12:25:15 -0500268{
269 if (mode & PTRACE_MODE_NOAUDIT)
Mickaël Salaüncf237052020-10-30 13:38:48 +0100270 return ns_capable_noaudit(ns, CAP_SYS_PTRACE);
271 return ns_capable(ns, CAP_SYS_PTRACE);
Eric Paris69f594a2012-01-03 12:25:15 -0500272}
273
Tetsuo Handa9f997982012-07-31 20:37:00 +0900274/* Returns 0 on success, -errno on denial. */
275static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700276{
David Howellsc69e8d92008-11-14 10:39:19 +1100277 const struct cred *cred = current_cred(), *tcred;
Eric W. Biedermanbfedb582016-10-13 21:23:16 -0500278 struct mm_struct *mm;
Jann Horncaaee622016-01-20 15:00:04 -0800279 kuid_t caller_uid;
280 kgid_t caller_gid;
281
282 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
283 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
284 return -EPERM;
285 }
David Howellsb6dff3e2008-11-14 10:39:16 +1100286
Eric W. Biedermandf26c402006-06-26 00:25:59 -0700287 /* May we inspect the given task?
288 * This check is used both for attaching with ptrace
289 * and for allowing access to sensitive information in /proc.
290 *
291 * ptrace_attach denies several cases that /proc allows
292 * because setting up the necessary parent/child relationship
293 * or halting the specified task is impossible.
294 */
Jann Horncaaee622016-01-20 15:00:04 -0800295
Eric W. Biedermandf26c402006-06-26 00:25:59 -0700296 /* Don't let security modules deny introspection */
Mark Grondona73af9632013-09-11 14:24:31 -0700297 if (same_thread_group(task, current))
Eric W. Biedermandf26c402006-06-26 00:25:59 -0700298 return 0;
David Howellsc69e8d92008-11-14 10:39:19 +1100299 rcu_read_lock();
Jann Horncaaee622016-01-20 15:00:04 -0800300 if (mode & PTRACE_MODE_FSCREDS) {
301 caller_uid = cred->fsuid;
302 caller_gid = cred->fsgid;
303 } else {
304 /*
305 * Using the euid would make more sense here, but something
306 * in userland might rely on the old behavior, and this
307 * shouldn't be a security problem since
308 * PTRACE_MODE_REALCREDS implies that the caller explicitly
309 * used a syscall that requests access to another process
310 * (and not a filesystem syscall to procfs).
311 */
312 caller_uid = cred->uid;
313 caller_gid = cred->gid;
314 }
David Howellsc69e8d92008-11-14 10:39:19 +1100315 tcred = __task_cred(task);
Jann Horncaaee622016-01-20 15:00:04 -0800316 if (uid_eq(caller_uid, tcred->euid) &&
317 uid_eq(caller_uid, tcred->suid) &&
318 uid_eq(caller_uid, tcred->uid) &&
319 gid_eq(caller_gid, tcred->egid) &&
320 gid_eq(caller_gid, tcred->sgid) &&
321 gid_eq(caller_gid, tcred->gid))
Serge E. Hallyn8409cca2011-03-23 16:43:20 -0700322 goto ok;
Mickaël Salaüncf237052020-10-30 13:38:48 +0100323 if (ptrace_has_cap(tcred->user_ns, mode))
Serge E. Hallyn8409cca2011-03-23 16:43:20 -0700324 goto ok;
325 rcu_read_unlock();
326 return -EPERM;
327ok:
David Howellsc69e8d92008-11-14 10:39:19 +1100328 rcu_read_unlock();
Jann Hornf6581f5b2019-05-29 13:31:57 +0200329 /*
330 * If a task drops privileges and becomes nondumpable (through a syscall
331 * like setresuid()) while we are trying to access it, we must ensure
332 * that the dumpability is read after the credentials; otherwise,
333 * we may be able to attach to a task that we shouldn't be able to
334 * attach to (as if the task had dropped privileges without becoming
335 * nondumpable).
336 * Pairs with a write barrier in commit_creds().
337 */
338 smp_rmb();
Eric W. Biedermanbfedb582016-10-13 21:23:16 -0500339 mm = task->mm;
340 if (mm &&
341 ((get_dumpable(mm) != SUID_DUMP_USER) &&
Mickaël Salaüncf237052020-10-30 13:38:48 +0100342 !ptrace_has_cap(mm->user_ns, mode)))
Eric W. Biedermanbfedb582016-10-13 21:23:16 -0500343 return -EPERM;
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700344
Ingo Molnar9e488582009-05-07 19:26:19 +1000345 return security_ptrace_access_check(task, mode);
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700346}
347
Stephen Smalley006ebb42008-05-19 08:32:49 -0400348bool ptrace_may_access(struct task_struct *task, unsigned int mode)
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700349{
350 int err;
351 task_lock(task);
Stephen Smalley006ebb42008-05-19 08:32:49 -0400352 err = __ptrace_may_access(task, mode);
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700353 task_unlock(task);
Roland McGrath3a709702009-04-07 23:21:06 -0700354 return !err;
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700355}
356
Tejun Heo3544d722011-06-14 11:20:15 +0200357static int ptrace_attach(struct task_struct *task, long request,
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -0700358 unsigned long addr,
Tejun Heo3544d722011-06-14 11:20:15 +0200359 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360{
Tejun Heo3544d722011-06-14 11:20:15 +0200361 bool seize = (request == PTRACE_SEIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 int retval;
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700363
Tejun Heo3544d722011-06-14 11:20:15 +0200364 retval = -EIO;
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -0700365 if (seize) {
366 if (addr != 0)
367 goto out;
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -0700368 if (flags & ~(unsigned long)PTRACE_O_MASK)
369 goto out;
370 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
371 } else {
372 flags = PT_PTRACED;
373 }
Tejun Heo3544d722011-06-14 11:20:15 +0200374
Al Viroa5cb0132007-03-20 13:58:35 -0400375 audit_ptrace(task);
376
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 retval = -EPERM;
Oleg Nesterovb79b7ba2009-06-17 16:27:31 -0700378 if (unlikely(task->flags & PF_KTHREAD))
379 goto out;
Pavel Emelyanovbac0abd2007-10-18 23:40:18 -0700380 if (same_thread_group(task, current))
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700381 goto out;
382
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700383 /*
384 * Protect exec's credential calculations against our interference;
Denys Vlasenko86b6c1f2012-03-23 15:02:41 -0700385 * SUID, SGID and LSM creds get determined differently
David Howells5e751e92009-05-08 13:55:22 +0100386 * under ptrace.
David Howellsd84f4f92008-11-14 10:39:23 +1100387 */
Oleg Nesterov793285f2009-07-05 12:08:26 -0700388 retval = -ERESTARTNOINTR;
KOSAKI Motohiro9b1bf122010-10-27 15:34:08 -0700389 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
David Howellsd84f4f92008-11-14 10:39:23 +1100390 goto out;
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700391
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700392 task_lock(task);
Jann Horncaaee622016-01-20 15:00:04 -0800393 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700394 task_unlock(task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 if (retval)
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700396 goto unlock_creds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700398 write_lock_irq(&tasklist_lock);
Oleg Nesterovb79b7ba2009-06-17 16:27:31 -0700399 retval = -EPERM;
400 if (unlikely(task->exit_state))
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700401 goto unlock_tasklist;
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700402 if (task->ptrace)
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700403 goto unlock_tasklist;
Oleg Nesterovb79b7ba2009-06-17 16:27:31 -0700404
Tejun Heo3544d722011-06-14 11:20:15 +0200405 if (seize)
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -0700406 flags |= PT_SEIZED;
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -0700407 task->ptrace = flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408
Eric W. Biedermanc70d9d82017-05-22 15:40:12 -0500409 ptrace_link(task, current);
Tejun Heo3544d722011-06-14 11:20:15 +0200410
411 /* SEIZE doesn't trap tracee on attach */
412 if (!seize)
Eric W. Biederman079b22d2018-09-03 10:32:52 +0200413 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
Oleg Nesterovb79b7ba2009-06-17 16:27:31 -0700414
Tejun Heod79fdd62011-03-23 10:37:00 +0100415 spin_lock(&task->sighand->siglock);
416
417 /*
Tejun Heo73ddff22011-06-14 11:20:14 +0200418 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
Tejun Heod79fdd62011-03-23 10:37:00 +0100419 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
420 * will be cleared if the child completes the transition or any
421 * event which clears the group stop states happens. We'll wait
422 * for the transition to complete before returning from this
423 * function.
424 *
425 * This hides STOPPED -> RUNNING -> TRACED transition from the
426 * attaching thread but a different thread in the same group can
427 * still observe the transient RUNNING state. IOW, if another
428 * thread's WNOHANG wait(2) on the stopped tracee races against
429 * ATTACH, the wait(2) may fail due to the transient RUNNING.
430 *
431 * The following task_is_stopped() test is safe as both transitions
432 * in and out of STOPPED are protected by siglock.
433 */
Tejun Heo7dd3db52011-06-02 11:14:00 +0200434 if (task_is_stopped(task) &&
Tejun Heo73ddff22011-06-14 11:20:14 +0200435 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
Oleg Nesterov910ffdb12013-01-21 20:47:41 +0100436 signal_wake_up_state(task, __TASK_STOPPED);
Tejun Heod79fdd62011-03-23 10:37:00 +0100437
438 spin_unlock(&task->sighand->siglock);
439
Oleg Nesterovb79b7ba2009-06-17 16:27:31 -0700440 retval = 0;
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700441unlock_tasklist:
442 write_unlock_irq(&tasklist_lock);
443unlock_creds:
KOSAKI Motohiro9b1bf122010-10-27 15:34:08 -0700444 mutex_unlock(&task->signal->cred_guard_mutex);
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700445out:
Vladimir Zapolskiyf701e5b2011-07-15 20:45:18 +0300446 if (!retval) {
Oleg Nesterov7c3b00e2016-01-20 14:59:55 -0800447 /*
448 * We do not bother to change retval or clear JOBCTL_TRAPPING
449 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
450 * not return to user-mode, it will exit and clear this bit in
451 * __ptrace_unlink() if it wasn't already cleared by the tracee;
452 * and until then nobody can ptrace this task.
453 */
454 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
Vladimir Zapolskiyf701e5b2011-07-15 20:45:18 +0300455 proc_ptrace_connector(task, PTRACE_ATTACH);
456 }
457
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 return retval;
459}
460
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700461/**
462 * ptrace_traceme -- helper for PTRACE_TRACEME
463 *
464 * Performs checks and sets PT_PTRACED.
465 * Should be used by all ptrace implementations for PTRACE_TRACEME.
466 */
Linus Torvaldse3e89cc2011-03-04 09:23:30 -0800467static int ptrace_traceme(void)
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700468{
469 int ret = -EPERM;
470
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700471 write_lock_irq(&tasklist_lock);
472 /* Are we already being traced? */
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700473 if (!current->ptrace) {
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700474 ret = security_ptrace_traceme(current->parent);
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700475 /*
476 * Check PF_EXITING to ensure ->real_parent has not passed
477 * exit_ptrace(). Otherwise we don't report the error but
478 * pretend ->real_parent untraces us right after return.
479 */
480 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
481 current->ptrace = PT_PTRACED;
Eric W. Biedermanc70d9d82017-05-22 15:40:12 -0500482 ptrace_link(current, current->real_parent);
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700483 }
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700484 }
Oleg Nesterov4b105cb2009-06-17 16:27:33 -0700485 write_unlock_irq(&tasklist_lock);
486
Oleg Nesterovf2f0b002009-06-17 16:27:32 -0700487 return ret;
488}
489
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700490/*
491 * Called with irqs disabled, returns true if childs should reap themselves.
492 */
493static int ignoring_children(struct sighand_struct *sigh)
494{
495 int ret;
496 spin_lock(&sigh->siglock);
497 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
498 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
499 spin_unlock(&sigh->siglock);
500 return ret;
501}
502
503/*
504 * Called with tasklist_lock held for writing.
505 * Unlink a traced task, and clean it up if it was a traced zombie.
506 * Return true if it needs to be reaped with release_task().
507 * (We can't call release_task() here because we already hold tasklist_lock.)
508 *
509 * If it's a zombie, our attachedness prevented normal parent notification
510 * or self-reaping. Do notification now if it would have happened earlier.
511 * If it should reap itself, return true.
512 *
Oleg Nesterova7f07652009-09-23 15:56:44 -0700513 * If it's our own child, there is no notification to do. But if our normal
514 * children self-reap, then this child was prevented by ptrace and we must
515 * reap it now, in that case we must also wake up sub-threads sleeping in
516 * do_wait().
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700517 */
518static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
519{
Oleg Nesterov9843a1e2011-06-22 23:08:53 +0200520 bool dead;
521
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700522 __ptrace_unlink(p);
523
Oleg Nesterov9843a1e2011-06-22 23:08:53 +0200524 if (p->exit_state != EXIT_ZOMBIE)
525 return false;
526
527 dead = !thread_group_leader(p);
528
529 if (!dead && thread_group_empty(p)) {
530 if (!same_thread_group(p->real_parent, tracer))
531 dead = do_notify_parent(p, p->exit_signal);
532 else if (ignoring_children(tracer->sighand)) {
533 __wake_up_parent(p, tracer);
Oleg Nesterov9843a1e2011-06-22 23:08:53 +0200534 dead = true;
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700535 }
536 }
Oleg Nesterov9843a1e2011-06-22 23:08:53 +0200537 /* Mark it as in the process of being reaped. */
538 if (dead)
539 p->exit_state = EXIT_DEAD;
540 return dead;
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700541}
542
Linus Torvaldse3e89cc2011-03-04 09:23:30 -0800543static int ptrace_detach(struct task_struct *child, unsigned int data)
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +0300544{
545 if (!valid_signal(data))
546 return -EIO;
547
548 /* Architecture-specific hardware disable .. */
549 ptrace_disable(child);
550
Oleg Nesterov95c3eb72009-04-02 16:58:11 -0700551 write_lock_irq(&tasklist_lock);
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700552 /*
Oleg Nesterov64a40962015-04-16 12:47:32 -0700553 * We rely on ptrace_freeze_traced(). It can't be killed and
554 * untraced by another thread, it can't be a zombie.
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700555 */
Oleg Nesterov64a40962015-04-16 12:47:32 -0700556 WARN_ON(!child->ptrace || child->exit_state);
557 /*
558 * tasklist_lock avoids the race with wait_task_stopped(), see
559 * the comment in ptrace_resume().
560 */
561 child->exit_code = data;
562 __ptrace_detach(current, child);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 write_unlock_irq(&tasklist_lock);
564
Vladimir Zapolskiyf701e5b2011-07-15 20:45:18 +0300565 proc_ptrace_connector(child, PTRACE_DETACH);
Oleg Nesterov45761452009-04-02 16:58:14 -0700566
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 return 0;
568}
569
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700570/*
Oleg Nesterovc7e49c12010-08-10 18:03:07 -0700571 * Detach all tasks we were using ptrace on. Called with tasklist held
Oleg Nesterov7c8bd232014-12-10 15:45:33 -0800572 * for writing.
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700573 */
Oleg Nesterov7c8bd232014-12-10 15:45:33 -0800574void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700575{
576 struct task_struct *p, *n;
Oleg Nesterovc7e49c12010-08-10 18:03:07 -0700577
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700578 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
Oleg Nesterov992fb6e2012-12-17 16:03:07 -0800579 if (unlikely(p->ptrace & PT_EXITKILL))
Eric W. Biederman079b22d2018-09-03 10:32:52 +0200580 send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
Oleg Nesterov992fb6e2012-12-17 16:03:07 -0800581
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700582 if (__ptrace_detach(tracer, p))
Oleg Nesterov7c8bd232014-12-10 15:45:33 -0800583 list_add(&p->ptrace_entry, dead);
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700584 }
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700585}
586
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
588{
589 int copied = 0;
590
591 while (len > 0) {
592 char buf[128];
593 int this_len, retval;
594
595 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
Eric W. Biederman84d77d32016-11-22 12:06:50 -0600596 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
597
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 if (!retval) {
599 if (copied)
600 break;
601 return -EIO;
602 }
603 if (copy_to_user(dst, buf, retval))
604 return -EFAULT;
605 copied += retval;
606 src += retval;
607 dst += retval;
Roland McGrath3a709702009-04-07 23:21:06 -0700608 len -= retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 }
610 return copied;
611}
612
613int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
614{
615 int copied = 0;
616
617 while (len > 0) {
618 char buf[128];
619 int this_len, retval;
620
621 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
622 if (copy_from_user(buf, src, this_len))
623 return -EFAULT;
Eric W. Biederman84d77d32016-11-22 12:06:50 -0600624 retval = ptrace_access_vm(tsk, dst, buf, this_len,
Lorenzo Stoakesf307ab62016-10-13 01:20:20 +0100625 FOLL_FORCE | FOLL_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 if (!retval) {
627 if (copied)
628 break;
629 return -EIO;
630 }
631 copied += retval;
632 src += retval;
633 dst += retval;
Roland McGrath3a709702009-04-07 23:21:06 -0700634 len -= retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 }
636 return copied;
637}
638
Namhyung Kim4abf9862010-10-27 15:33:45 -0700639static int ptrace_setoptions(struct task_struct *child, unsigned long data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640{
Denys Vlasenko86b6c1f2012-03-23 15:02:41 -0700641 unsigned flags;
642
Denys Vlasenko8c5cf9e2012-03-23 15:02:40 -0700643 if (data & ~(unsigned long)PTRACE_O_MASK)
644 return -EINVAL;
645
Tycho Andersen13c4a902015-06-13 09:02:48 -0600646 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
Masahiro Yamada97f26452016-08-03 13:45:50 -0700647 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
648 !IS_ENABLED(CONFIG_SECCOMP))
Tycho Andersen13c4a902015-06-13 09:02:48 -0600649 return -EINVAL;
650
651 if (!capable(CAP_SYS_ADMIN))
652 return -EPERM;
653
654 if (seccomp_mode(&current->seccomp) != SECCOMP_MODE_DISABLED ||
655 current->ptrace & PT_SUSPEND_SECCOMP)
656 return -EPERM;
657 }
658
Denys Vlasenko86b6c1f2012-03-23 15:02:41 -0700659 /* Avoid intermediate state when all opts are cleared */
660 flags = child->ptrace;
661 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
662 flags |= (data << PT_OPT_FLAG_SHIFT);
663 child->ptrace = flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664
Denys Vlasenko8c5cf9e2012-03-23 15:02:40 -0700665 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666}
667
Eric W. Biedermanae7795b2018-09-25 11:27:20 +0200668static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669{
Oleg Nesterove4961252009-06-17 16:27:36 -0700670 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 int error = -ESRCH;
672
Oleg Nesterove4961252009-06-17 16:27:36 -0700673 if (lock_task_sighand(child, &flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 if (likely(child->last_siginfo != NULL)) {
Eric W. Biederman0752d7bf2017-07-24 15:08:16 -0500676 copy_siginfo(info, child->last_siginfo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 error = 0;
678 }
Oleg Nesterove4961252009-06-17 16:27:36 -0700679 unlock_task_sighand(child, &flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 return error;
682}
683
Eric W. Biedermanae7795b2018-09-25 11:27:20 +0200684static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685{
Oleg Nesterove4961252009-06-17 16:27:36 -0700686 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 int error = -ESRCH;
688
Oleg Nesterove4961252009-06-17 16:27:36 -0700689 if (lock_task_sighand(child, &flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 if (likely(child->last_siginfo != NULL)) {
Eric W. Biederman0752d7bf2017-07-24 15:08:16 -0500692 copy_siginfo(child->last_siginfo, info);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 error = 0;
694 }
Oleg Nesterove4961252009-06-17 16:27:36 -0700695 unlock_task_sighand(child, &flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 return error;
698}
699
Andrey Vagin84c751b2013-04-30 15:27:59 -0700700static int ptrace_peek_siginfo(struct task_struct *child,
701 unsigned long addr,
702 unsigned long data)
703{
704 struct ptrace_peeksiginfo_args arg;
705 struct sigpending *pending;
706 struct sigqueue *q;
707 int ret, i;
708
709 ret = copy_from_user(&arg, (void __user *) addr,
710 sizeof(struct ptrace_peeksiginfo_args));
711 if (ret)
712 return -EFAULT;
713
714 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
715 return -EINVAL; /* unknown flags */
716
717 if (arg.nr < 0)
718 return -EINVAL;
719
Eric W. Biedermanf6e2aa92019-05-28 18:46:37 -0500720 /* Ensure arg.off fits in an unsigned long */
721 if (arg.off > ULONG_MAX)
722 return 0;
723
Andrey Vagin84c751b2013-04-30 15:27:59 -0700724 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
725 pending = &child->signal->shared_pending;
726 else
727 pending = &child->pending;
728
729 for (i = 0; i < arg.nr; ) {
Eric W. Biedermanae7795b2018-09-25 11:27:20 +0200730 kernel_siginfo_t info;
Eric W. Biedermanf6e2aa92019-05-28 18:46:37 -0500731 unsigned long off = arg.off + i;
732 bool found = false;
Andrey Vagin84c751b2013-04-30 15:27:59 -0700733
734 spin_lock_irq(&child->sighand->siglock);
735 list_for_each_entry(q, &pending->list, list) {
736 if (!off--) {
Eric W. Biedermanf6e2aa92019-05-28 18:46:37 -0500737 found = true;
Andrey Vagin84c751b2013-04-30 15:27:59 -0700738 copy_siginfo(&info, &q->info);
739 break;
740 }
741 }
742 spin_unlock_irq(&child->sighand->siglock);
743
Eric W. Biedermanf6e2aa92019-05-28 18:46:37 -0500744 if (!found) /* beyond the end of the list */
Andrey Vagin84c751b2013-04-30 15:27:59 -0700745 break;
746
747#ifdef CONFIG_COMPAT
Andy Lutomirski5c465212016-03-22 14:24:55 -0700748 if (unlikely(in_compat_syscall())) {
Andrey Vagin84c751b2013-04-30 15:27:59 -0700749 compat_siginfo_t __user *uinfo = compat_ptr(data);
750
Eric W. Biedermancc731522017-07-16 22:36:59 -0500751 if (copy_siginfo_to_user32(uinfo, &info)) {
Mathieu Desnoyers706b23b2013-06-28 09:49:46 -0400752 ret = -EFAULT;
753 break;
754 }
755
Andrey Vagin84c751b2013-04-30 15:27:59 -0700756 } else
757#endif
758 {
759 siginfo_t __user *uinfo = (siginfo_t __user *) data;
760
Eric W. Biedermancc731522017-07-16 22:36:59 -0500761 if (copy_siginfo_to_user(uinfo, &info)) {
Mathieu Desnoyers706b23b2013-06-28 09:49:46 -0400762 ret = -EFAULT;
763 break;
764 }
Andrey Vagin84c751b2013-04-30 15:27:59 -0700765 }
766
767 data += sizeof(siginfo_t);
768 i++;
769
770 if (signal_pending(current))
771 break;
772
773 cond_resched();
774 }
775
776 if (i > 0)
777 return i;
778
779 return ret;
780}
Roland McGrath36df29d2008-01-30 13:30:51 +0100781
782#ifdef PTRACE_SINGLESTEP
783#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
784#else
785#define is_singlestep(request) 0
786#endif
787
Roland McGrath5b88abb2008-01-30 13:30:53 +0100788#ifdef PTRACE_SINGLEBLOCK
789#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
790#else
791#define is_singleblock(request) 0
792#endif
793
Roland McGrath36df29d2008-01-30 13:30:51 +0100794#ifdef PTRACE_SYSEMU
795#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
796#else
797#define is_sysemu_singlestep(request) 0
798#endif
799
Namhyung Kim4abf9862010-10-27 15:33:45 -0700800static int ptrace_resume(struct task_struct *child, long request,
801 unsigned long data)
Roland McGrath36df29d2008-01-30 13:30:51 +0100802{
Oleg Nesterovb72c1862015-04-16 12:47:29 -0700803 bool need_siglock;
804
Roland McGrath36df29d2008-01-30 13:30:51 +0100805 if (!valid_signal(data))
806 return -EIO;
807
808 if (request == PTRACE_SYSCALL)
Gabriel Krisman Bertazi64c19ba2020-11-16 12:42:02 -0500809 set_task_syscall_work(child, SYSCALL_TRACE);
Roland McGrath36df29d2008-01-30 13:30:51 +0100810 else
Gabriel Krisman Bertazi64c19ba2020-11-16 12:42:02 -0500811 clear_task_syscall_work(child, SYSCALL_TRACE);
Roland McGrath36df29d2008-01-30 13:30:51 +0100812
Gabriel Krisman Bertazi64eb35f2020-11-16 12:42:03 -0500813#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
Roland McGrath36df29d2008-01-30 13:30:51 +0100814 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
Gabriel Krisman Bertazi64eb35f2020-11-16 12:42:03 -0500815 set_task_syscall_work(child, SYSCALL_EMU);
Roland McGrath36df29d2008-01-30 13:30:51 +0100816 else
Gabriel Krisman Bertazi64eb35f2020-11-16 12:42:03 -0500817 clear_task_syscall_work(child, SYSCALL_EMU);
Roland McGrath36df29d2008-01-30 13:30:51 +0100818#endif
819
Roland McGrath5b88abb2008-01-30 13:30:53 +0100820 if (is_singleblock(request)) {
821 if (unlikely(!arch_has_block_step()))
822 return -EIO;
823 user_enable_block_step(child);
824 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
Roland McGrath36df29d2008-01-30 13:30:51 +0100825 if (unlikely(!arch_has_single_step()))
826 return -EIO;
827 user_enable_single_step(child);
Roland McGrath3a709702009-04-07 23:21:06 -0700828 } else {
Roland McGrath36df29d2008-01-30 13:30:51 +0100829 user_disable_single_step(child);
Roland McGrath3a709702009-04-07 23:21:06 -0700830 }
Roland McGrath36df29d2008-01-30 13:30:51 +0100831
Oleg Nesterovb72c1862015-04-16 12:47:29 -0700832 /*
833 * Change ->exit_code and ->state under siglock to avoid the race
834 * with wait_task_stopped() in between; a non-zero ->exit_code will
835 * wrongly look like another report from tracee.
836 *
837 * Note that we need siglock even if ->exit_code == data and/or this
838 * status was not reported yet, the new status must not be cleared by
839 * wait_task_stopped() after resume.
840 *
841 * If data == 0 we do not care if wait_task_stopped() reports the old
842 * status and clears the code too; this can't race with the tracee, it
843 * takes siglock after resume.
844 */
845 need_siglock = data && !thread_group_empty(current);
846 if (need_siglock)
847 spin_lock_irq(&child->sighand->siglock);
Roland McGrath36df29d2008-01-30 13:30:51 +0100848 child->exit_code = data;
Oleg Nesterov0666fb52011-05-25 19:20:21 +0200849 wake_up_state(child, __TASK_TRACED);
Oleg Nesterovb72c1862015-04-16 12:47:29 -0700850 if (need_siglock)
851 spin_unlock_irq(&child->sighand->siglock);
Roland McGrath36df29d2008-01-30 13:30:51 +0100852
853 return 0;
854}
855
Suresh Siddha2225a122010-02-11 11:51:00 -0800856#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
857
858static const struct user_regset *
859find_regset(const struct user_regset_view *view, unsigned int type)
860{
861 const struct user_regset *regset;
862 int n;
863
864 for (n = 0; n < view->n; ++n) {
865 regset = view->regsets + n;
866 if (regset->core_note_type == type)
867 return regset;
868 }
869
870 return NULL;
871}
872
873static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
874 struct iovec *kiov)
875{
876 const struct user_regset_view *view = task_user_regset_view(task);
877 const struct user_regset *regset = find_regset(view, type);
878 int regset_no;
879
880 if (!regset || (kiov->iov_len % regset->size) != 0)
Suresh Siddhac6a0dd72010-02-22 14:51:32 -0800881 return -EINVAL;
Suresh Siddha2225a122010-02-11 11:51:00 -0800882
883 regset_no = regset - view->regsets;
884 kiov->iov_len = min(kiov->iov_len,
885 (__kernel_size_t) (regset->n * regset->size));
886
887 if (req == PTRACE_GETREGSET)
888 return copy_regset_to_user(task, view, regset_no, 0,
889 kiov->iov_len, kiov->iov_base);
890 else
891 return copy_regset_from_user(task, view, regset_no, 0,
892 kiov->iov_len, kiov->iov_base);
893}
894
Josh Stonee8440c142013-01-13 19:03:34 +0100895/*
896 * This is declared in linux/regset.h and defined in machine-dependent
897 * code. We put the export here, near the primary machine-neutral use,
898 * to ensure no machine forgets it.
899 */
900EXPORT_SYMBOL_GPL(task_user_regset_view);
Elvira Khabirova201766a2019-07-16 16:29:42 -0700901
902static unsigned long
903ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
904 struct ptrace_syscall_info *info)
905{
906 unsigned long args[ARRAY_SIZE(info->entry.args)];
907 int i;
908
909 info->op = PTRACE_SYSCALL_INFO_ENTRY;
910 info->entry.nr = syscall_get_nr(child, regs);
911 syscall_get_arguments(child, regs, args);
912 for (i = 0; i < ARRAY_SIZE(args); i++)
913 info->entry.args[i] = args[i];
914
915 /* args is the last field in struct ptrace_syscall_info.entry */
916 return offsetofend(struct ptrace_syscall_info, entry.args);
917}
918
919static unsigned long
920ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
921 struct ptrace_syscall_info *info)
922{
923 /*
924 * As struct ptrace_syscall_info.entry is currently a subset
925 * of struct ptrace_syscall_info.seccomp, it makes sense to
926 * initialize that subset using ptrace_get_syscall_info_entry().
927 * This can be reconsidered in the future if these structures
928 * diverge significantly enough.
929 */
930 ptrace_get_syscall_info_entry(child, regs, info);
931 info->op = PTRACE_SYSCALL_INFO_SECCOMP;
932 info->seccomp.ret_data = child->ptrace_message;
933
934 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */
935 return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
936}
937
938static unsigned long
939ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
940 struct ptrace_syscall_info *info)
941{
942 info->op = PTRACE_SYSCALL_INFO_EXIT;
943 info->exit.rval = syscall_get_error(child, regs);
944 info->exit.is_error = !!info->exit.rval;
945 if (!info->exit.is_error)
946 info->exit.rval = syscall_get_return_value(child, regs);
947
948 /* is_error is the last field in struct ptrace_syscall_info.exit */
949 return offsetofend(struct ptrace_syscall_info, exit.is_error);
950}
951
952static int
953ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
954 void __user *datavp)
955{
956 struct pt_regs *regs = task_pt_regs(child);
957 struct ptrace_syscall_info info = {
958 .op = PTRACE_SYSCALL_INFO_NONE,
959 .arch = syscall_get_arch(child),
960 .instruction_pointer = instruction_pointer(regs),
961 .stack_pointer = user_stack_pointer(regs),
962 };
963 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
964 unsigned long write_size;
965
966 /*
967 * This does not need lock_task_sighand() to access
968 * child->last_siginfo because ptrace_freeze_traced()
969 * called earlier by ptrace_check_attach() ensures that
970 * the tracee cannot go away and clear its last_siginfo.
971 */
972 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
973 case SIGTRAP | 0x80:
974 switch (child->ptrace_message) {
975 case PTRACE_EVENTMSG_SYSCALL_ENTRY:
976 actual_size = ptrace_get_syscall_info_entry(child, regs,
977 &info);
978 break;
979 case PTRACE_EVENTMSG_SYSCALL_EXIT:
980 actual_size = ptrace_get_syscall_info_exit(child, regs,
981 &info);
982 break;
983 }
984 break;
985 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
986 actual_size = ptrace_get_syscall_info_seccomp(child, regs,
987 &info);
988 break;
989 }
990
991 write_size = min(actual_size, user_size);
992 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
993}
994#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
Suresh Siddha2225a122010-02-11 11:51:00 -0800995
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996int ptrace_request(struct task_struct *child, long request,
Namhyung Kim4abf9862010-10-27 15:33:45 -0700997 unsigned long addr, unsigned long data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998{
Tejun Heofca26f22011-06-14 11:20:16 +0200999 bool seized = child->ptrace & PT_SEIZED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 int ret = -EIO;
Eric W. Biedermanae7795b2018-09-25 11:27:20 +02001001 kernel_siginfo_t siginfo, *si;
Namhyung Kim9fed81d2010-10-27 15:33:46 -07001002 void __user *datavp = (void __user *) data;
1003 unsigned long __user *datalp = datavp;
Tejun Heofca26f22011-06-14 11:20:16 +02001004 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005
1006 switch (request) {
Roland McGrath16c3e382008-01-30 13:31:47 +01001007 case PTRACE_PEEKTEXT:
1008 case PTRACE_PEEKDATA:
1009 return generic_ptrace_peekdata(child, addr, data);
1010 case PTRACE_POKETEXT:
1011 case PTRACE_POKEDATA:
1012 return generic_ptrace_pokedata(child, addr, data);
1013
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014#ifdef PTRACE_OLDSETOPTIONS
1015 case PTRACE_OLDSETOPTIONS:
1016#endif
1017 case PTRACE_SETOPTIONS:
1018 ret = ptrace_setoptions(child, data);
1019 break;
1020 case PTRACE_GETEVENTMSG:
Namhyung Kim9fed81d2010-10-27 15:33:46 -07001021 ret = put_user(child->ptrace_message, datalp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022 break;
Roland McGrathe16b2782008-04-20 13:10:12 -07001023
Andrey Vagin84c751b2013-04-30 15:27:59 -07001024 case PTRACE_PEEKSIGINFO:
1025 ret = ptrace_peek_siginfo(child, addr, data);
1026 break;
1027
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028 case PTRACE_GETSIGINFO:
Roland McGrathe16b2782008-04-20 13:10:12 -07001029 ret = ptrace_getsiginfo(child, &siginfo);
1030 if (!ret)
Namhyung Kim9fed81d2010-10-27 15:33:46 -07001031 ret = copy_siginfo_to_user(datavp, &siginfo);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032 break;
Roland McGrathe16b2782008-04-20 13:10:12 -07001033
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034 case PTRACE_SETSIGINFO:
Eric W. Biederman4cd2e0e2018-04-18 17:30:19 -05001035 ret = copy_siginfo_from_user(&siginfo, datavp);
1036 if (!ret)
Roland McGrathe16b2782008-04-20 13:10:12 -07001037 ret = ptrace_setsiginfo(child, &siginfo);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038 break;
Roland McGrathe16b2782008-04-20 13:10:12 -07001039
Andrei Vaginfcfc2aa02019-03-28 20:44:13 -07001040 case PTRACE_GETSIGMASK: {
1041 sigset_t *mask;
1042
Andrey Vagin29000ca2013-07-03 15:08:12 -07001043 if (addr != sizeof(sigset_t)) {
1044 ret = -EINVAL;
1045 break;
1046 }
1047
Andrei Vaginfcfc2aa02019-03-28 20:44:13 -07001048 if (test_tsk_restore_sigmask(child))
1049 mask = &child->saved_sigmask;
1050 else
1051 mask = &child->blocked;
1052
1053 if (copy_to_user(datavp, mask, sizeof(sigset_t)))
Andrey Vagin29000ca2013-07-03 15:08:12 -07001054 ret = -EFAULT;
1055 else
1056 ret = 0;
1057
1058 break;
Andrei Vaginfcfc2aa02019-03-28 20:44:13 -07001059 }
Andrey Vagin29000ca2013-07-03 15:08:12 -07001060
1061 case PTRACE_SETSIGMASK: {
1062 sigset_t new_set;
1063
1064 if (addr != sizeof(sigset_t)) {
1065 ret = -EINVAL;
1066 break;
1067 }
1068
1069 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
1070 ret = -EFAULT;
1071 break;
1072 }
1073
1074 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
1075
1076 /*
1077 * Every thread does recalc_sigpending() after resume, so
1078 * retarget_shared_pending() and recalc_sigpending() are not
1079 * called here.
1080 */
1081 spin_lock_irq(&child->sighand->siglock);
1082 child->blocked = new_set;
1083 spin_unlock_irq(&child->sighand->siglock);
1084
Andrei Vaginfcfc2aa02019-03-28 20:44:13 -07001085 clear_tsk_restore_sigmask(child);
1086
Andrey Vagin29000ca2013-07-03 15:08:12 -07001087 ret = 0;
1088 break;
1089 }
1090
Tejun Heofca26f22011-06-14 11:20:16 +02001091 case PTRACE_INTERRUPT:
1092 /*
1093 * Stop tracee without any side-effect on signal or job
1094 * control. At least one trap is guaranteed to happen
1095 * after this request. If @child is already trapped, the
1096 * current trap is not disturbed and another trap will
1097 * happen after the current trap is ended with PTRACE_CONT.
1098 *
1099 * The actual trap might not be PTRACE_EVENT_STOP trap but
1100 * the pending condition is cleared regardless.
1101 */
1102 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1103 break;
1104
Tejun Heo544b2c92011-06-14 11:20:18 +02001105 /*
1106 * INTERRUPT doesn't disturb existing trap sans one
1107 * exception. If ptracer issued LISTEN for the current
1108 * STOP, this INTERRUPT should clear LISTEN and re-trap
1109 * tracee into STOP.
1110 */
Tejun Heofca26f22011-06-14 11:20:16 +02001111 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
Oleg Nesterov910ffdb12013-01-21 20:47:41 +01001112 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
Tejun Heo544b2c92011-06-14 11:20:18 +02001113
1114 unlock_task_sighand(child, &flags);
1115 ret = 0;
1116 break;
1117
1118 case PTRACE_LISTEN:
1119 /*
1120 * Listen for events. Tracee must be in STOP. It's not
1121 * resumed per-se but is not considered to be in TRACED by
1122 * wait(2) or ptrace(2). If an async event (e.g. group
1123 * stop state change) happens, tracee will enter STOP trap
1124 * again. Alternatively, ptracer can issue INTERRUPT to
1125 * finish listening and re-trap tracee into STOP.
1126 */
1127 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1128 break;
1129
1130 si = child->last_siginfo;
Oleg Nesterovf9d81f62011-09-25 19:46:22 +02001131 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
1132 child->jobctl |= JOBCTL_LISTENING;
1133 /*
1134 * If NOTIFY is set, it means event happened between
1135 * start of this trap and now. Trigger re-trap.
1136 */
1137 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
Oleg Nesterov910ffdb12013-01-21 20:47:41 +01001138 ptrace_signal_wake_up(child, true);
Oleg Nesterovf9d81f62011-09-25 19:46:22 +02001139 ret = 0;
1140 }
Tejun Heofca26f22011-06-14 11:20:16 +02001141 unlock_task_sighand(child, &flags);
Tejun Heofca26f22011-06-14 11:20:16 +02001142 break;
1143
Alexey Dobriyan1bcf5482007-10-16 01:23:45 -07001144 case PTRACE_DETACH: /* detach a process that was attached. */
1145 ret = ptrace_detach(child, data);
1146 break;
Roland McGrath36df29d2008-01-30 13:30:51 +01001147
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001148#ifdef CONFIG_BINFMT_ELF_FDPIC
1149 case PTRACE_GETFDPIC: {
Oleg Nesterove0129ef2010-05-26 14:42:53 -07001150 struct mm_struct *mm = get_task_mm(child);
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001151 unsigned long tmp = 0;
1152
Oleg Nesterove0129ef2010-05-26 14:42:53 -07001153 ret = -ESRCH;
1154 if (!mm)
1155 break;
1156
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001157 switch (addr) {
1158 case PTRACE_GETFDPIC_EXEC:
Oleg Nesterove0129ef2010-05-26 14:42:53 -07001159 tmp = mm->context.exec_fdpic_loadmap;
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001160 break;
1161 case PTRACE_GETFDPIC_INTERP:
Oleg Nesterove0129ef2010-05-26 14:42:53 -07001162 tmp = mm->context.interp_fdpic_loadmap;
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001163 break;
1164 default:
1165 break;
1166 }
Oleg Nesterove0129ef2010-05-26 14:42:53 -07001167 mmput(mm);
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001168
Namhyung Kim9fed81d2010-10-27 15:33:46 -07001169 ret = put_user(tmp, datalp);
Mike Frysinger9c1a1252010-05-26 14:42:52 -07001170 break;
1171 }
1172#endif
1173
Roland McGrath36df29d2008-01-30 13:30:51 +01001174#ifdef PTRACE_SINGLESTEP
1175 case PTRACE_SINGLESTEP:
1176#endif
Roland McGrath5b88abb2008-01-30 13:30:53 +01001177#ifdef PTRACE_SINGLEBLOCK
1178 case PTRACE_SINGLEBLOCK:
1179#endif
Roland McGrath36df29d2008-01-30 13:30:51 +01001180#ifdef PTRACE_SYSEMU
1181 case PTRACE_SYSEMU:
1182 case PTRACE_SYSEMU_SINGLESTEP:
1183#endif
1184 case PTRACE_SYSCALL:
1185 case PTRACE_CONT:
1186 return ptrace_resume(child, request, data);
1187
1188 case PTRACE_KILL:
1189 if (child->exit_state) /* already dead */
1190 return 0;
1191 return ptrace_resume(child, request, SIGKILL);
1192
Suresh Siddha2225a122010-02-11 11:51:00 -08001193#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1194 case PTRACE_GETREGSET:
Andrey Vagin29000ca2013-07-03 15:08:12 -07001195 case PTRACE_SETREGSET: {
Suresh Siddha2225a122010-02-11 11:51:00 -08001196 struct iovec kiov;
Namhyung Kim9fed81d2010-10-27 15:33:46 -07001197 struct iovec __user *uiov = datavp;
Suresh Siddha2225a122010-02-11 11:51:00 -08001198
Linus Torvalds96d4f262019-01-03 18:57:57 -08001199 if (!access_ok(uiov, sizeof(*uiov)))
Suresh Siddha2225a122010-02-11 11:51:00 -08001200 return -EFAULT;
1201
1202 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1203 __get_user(kiov.iov_len, &uiov->iov_len))
1204 return -EFAULT;
1205
1206 ret = ptrace_regset(child, request, addr, &kiov);
1207 if (!ret)
1208 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1209 break;
1210 }
Elvira Khabirova201766a2019-07-16 16:29:42 -07001211
1212 case PTRACE_GET_SYSCALL_INFO:
1213 ret = ptrace_get_syscall_info(child, addr, datavp);
1214 break;
Suresh Siddha2225a122010-02-11 11:51:00 -08001215#endif
Tycho Andersenf8e529ed2015-10-27 09:23:59 +09001216
1217 case PTRACE_SECCOMP_GET_FILTER:
1218 ret = seccomp_get_filter(child, addr, datavp);
1219 break;
1220
Tycho Andersen26500472017-10-11 09:39:21 -06001221 case PTRACE_SECCOMP_GET_METADATA:
1222 ret = seccomp_get_metadata(child, addr, datavp);
1223 break;
1224
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225 default:
1226 break;
1227 }
1228
1229 return ret;
1230}
Christoph Hellwig481bed42005-11-07 00:59:47 -08001231
Christoph Hellwig0ac15552007-10-16 01:26:37 -07001232#ifndef arch_ptrace_attach
1233#define arch_ptrace_attach(child) do { } while (0)
1234#endif
1235
Namhyung Kim4abf9862010-10-27 15:33:45 -07001236SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1237 unsigned long, data)
Christoph Hellwig481bed42005-11-07 00:59:47 -08001238{
1239 struct task_struct *child;
1240 long ret;
1241
Christoph Hellwig6b9c7ed82006-01-08 01:02:33 -08001242 if (request == PTRACE_TRACEME) {
1243 ret = ptrace_traceme();
Haavard Skinnemoen6ea6dd92007-11-27 13:02:40 +01001244 if (!ret)
1245 arch_ptrace_attach(current);
Christoph Hellwig481bed42005-11-07 00:59:47 -08001246 goto out;
Christoph Hellwig6b9c7ed82006-01-08 01:02:33 -08001247 }
1248
Mike Rapoport2ee08262018-02-06 15:40:17 -08001249 child = find_get_task_by_vpid(pid);
1250 if (!child) {
1251 ret = -ESRCH;
Christoph Hellwig6b9c7ed82006-01-08 01:02:33 -08001252 goto out;
1253 }
Christoph Hellwig481bed42005-11-07 00:59:47 -08001254
Tejun Heo3544d722011-06-14 11:20:15 +02001255 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -07001256 ret = ptrace_attach(child, request, addr, data);
Christoph Hellwig0ac15552007-10-16 01:26:37 -07001257 /*
1258 * Some architectures need to do book-keeping after
1259 * a ptrace attach.
1260 */
1261 if (!ret)
1262 arch_ptrace_attach(child);
Christoph Hellwig005f18d2005-11-13 16:06:33 -08001263 goto out_put_task_struct;
Christoph Hellwig481bed42005-11-07 00:59:47 -08001264 }
1265
Tejun Heofca26f22011-06-14 11:20:16 +02001266 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1267 request == PTRACE_INTERRUPT);
Christoph Hellwig481bed42005-11-07 00:59:47 -08001268 if (ret < 0)
1269 goto out_put_task_struct;
1270
1271 ret = arch_ptrace(child, request, addr, data);
Oleg Nesterov9899d112013-01-21 20:48:00 +01001272 if (ret || request != PTRACE_DETACH)
1273 ptrace_unfreeze_traced(child);
Christoph Hellwig481bed42005-11-07 00:59:47 -08001274
1275 out_put_task_struct:
1276 put_task_struct(child);
1277 out:
Christoph Hellwig481bed42005-11-07 00:59:47 -08001278 return ret;
1279}
Alexey Dobriyan76647322007-07-17 04:03:43 -07001280
Namhyung Kim4abf9862010-10-27 15:33:45 -07001281int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1282 unsigned long data)
Alexey Dobriyan76647322007-07-17 04:03:43 -07001283{
1284 unsigned long tmp;
1285 int copied;
1286
Eric W. Biederman84d77d32016-11-22 12:06:50 -06001287 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
Alexey Dobriyan76647322007-07-17 04:03:43 -07001288 if (copied != sizeof(tmp))
1289 return -EIO;
1290 return put_user(tmp, (unsigned long __user *)data);
1291}
Alexey Dobriyanf284ce72007-07-17 04:03:44 -07001292
Namhyung Kim4abf9862010-10-27 15:33:45 -07001293int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1294 unsigned long data)
Alexey Dobriyanf284ce72007-07-17 04:03:44 -07001295{
1296 int copied;
1297
Eric W. Biederman84d77d32016-11-22 12:06:50 -06001298 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
Lorenzo Stoakesf307ab62016-10-13 01:20:20 +01001299 FOLL_FORCE | FOLL_WRITE);
Alexey Dobriyanf284ce72007-07-17 04:03:44 -07001300 return (copied == sizeof(data)) ? 0 : -EIO;
1301}
Roland McGrath032d82d2008-01-30 13:31:47 +01001302
Christoph Hellwig96b89362008-11-25 08:10:03 +01001303#if defined CONFIG_COMPAT
Roland McGrath032d82d2008-01-30 13:31:47 +01001304
1305int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1306 compat_ulong_t addr, compat_ulong_t data)
1307{
1308 compat_ulong_t __user *datap = compat_ptr(data);
1309 compat_ulong_t word;
Eric W. Biedermanae7795b2018-09-25 11:27:20 +02001310 kernel_siginfo_t siginfo;
Roland McGrath032d82d2008-01-30 13:31:47 +01001311 int ret;
1312
1313 switch (request) {
1314 case PTRACE_PEEKTEXT:
1315 case PTRACE_PEEKDATA:
Eric W. Biederman84d77d32016-11-22 12:06:50 -06001316 ret = ptrace_access_vm(child, addr, &word, sizeof(word),
Lorenzo Stoakesf307ab62016-10-13 01:20:20 +01001317 FOLL_FORCE);
Roland McGrath032d82d2008-01-30 13:31:47 +01001318 if (ret != sizeof(word))
1319 ret = -EIO;
1320 else
1321 ret = put_user(word, datap);
1322 break;
1323
1324 case PTRACE_POKETEXT:
1325 case PTRACE_POKEDATA:
Eric W. Biederman84d77d32016-11-22 12:06:50 -06001326 ret = ptrace_access_vm(child, addr, &data, sizeof(data),
Lorenzo Stoakesf307ab62016-10-13 01:20:20 +01001327 FOLL_FORCE | FOLL_WRITE);
Roland McGrath032d82d2008-01-30 13:31:47 +01001328 ret = (ret != sizeof(data) ? -EIO : 0);
1329 break;
1330
1331 case PTRACE_GETEVENTMSG:
1332 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1333 break;
1334
Roland McGrathe16b2782008-04-20 13:10:12 -07001335 case PTRACE_GETSIGINFO:
1336 ret = ptrace_getsiginfo(child, &siginfo);
1337 if (!ret)
1338 ret = copy_siginfo_to_user32(
1339 (struct compat_siginfo __user *) datap,
1340 &siginfo);
1341 break;
1342
1343 case PTRACE_SETSIGINFO:
Eric W. Biederman4cd2e0e2018-04-18 17:30:19 -05001344 ret = copy_siginfo_from_user32(
1345 &siginfo, (struct compat_siginfo __user *) datap);
1346 if (!ret)
Roland McGrathe16b2782008-04-20 13:10:12 -07001347 ret = ptrace_setsiginfo(child, &siginfo);
1348 break;
Suresh Siddha2225a122010-02-11 11:51:00 -08001349#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1350 case PTRACE_GETREGSET:
1351 case PTRACE_SETREGSET:
1352 {
1353 struct iovec kiov;
1354 struct compat_iovec __user *uiov =
1355 (struct compat_iovec __user *) datap;
1356 compat_uptr_t ptr;
1357 compat_size_t len;
1358
Linus Torvalds96d4f262019-01-03 18:57:57 -08001359 if (!access_ok(uiov, sizeof(*uiov)))
Suresh Siddha2225a122010-02-11 11:51:00 -08001360 return -EFAULT;
1361
1362 if (__get_user(ptr, &uiov->iov_base) ||
1363 __get_user(len, &uiov->iov_len))
1364 return -EFAULT;
1365
1366 kiov.iov_base = compat_ptr(ptr);
1367 kiov.iov_len = len;
1368
1369 ret = ptrace_regset(child, request, addr, &kiov);
1370 if (!ret)
1371 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1372 break;
1373 }
1374#endif
Roland McGrathe16b2782008-04-20 13:10:12 -07001375
Roland McGrath032d82d2008-01-30 13:31:47 +01001376 default:
1377 ret = ptrace_request(child, request, addr, data);
1378 }
1379
1380 return ret;
1381}
Roland McGrathc269f192008-01-30 13:31:48 +01001382
Heiko Carstens62a6fa972014-03-03 16:11:13 +01001383COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1384 compat_long_t, addr, compat_long_t, data)
Roland McGrathc269f192008-01-30 13:31:48 +01001385{
1386 struct task_struct *child;
1387 long ret;
1388
Roland McGrathc269f192008-01-30 13:31:48 +01001389 if (request == PTRACE_TRACEME) {
1390 ret = ptrace_traceme();
1391 goto out;
1392 }
1393
Mike Rapoport2ee08262018-02-06 15:40:17 -08001394 child = find_get_task_by_vpid(pid);
1395 if (!child) {
1396 ret = -ESRCH;
Roland McGrathc269f192008-01-30 13:31:48 +01001397 goto out;
1398 }
1399
Tejun Heo3544d722011-06-14 11:20:15 +02001400 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
Denys Vlasenkoaa9147c2012-03-23 15:02:42 -07001401 ret = ptrace_attach(child, request, addr, data);
Roland McGrathc269f192008-01-30 13:31:48 +01001402 /*
1403 * Some architectures need to do book-keeping after
1404 * a ptrace attach.
1405 */
1406 if (!ret)
1407 arch_ptrace_attach(child);
1408 goto out_put_task_struct;
1409 }
1410
Tejun Heofca26f22011-06-14 11:20:16 +02001411 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1412 request == PTRACE_INTERRUPT);
Oleg Nesterov9899d112013-01-21 20:48:00 +01001413 if (!ret) {
Roland McGrathc269f192008-01-30 13:31:48 +01001414 ret = compat_arch_ptrace(child, request, addr, data);
Oleg Nesterov9899d112013-01-21 20:48:00 +01001415 if (ret || request != PTRACE_DETACH)
1416 ptrace_unfreeze_traced(child);
1417 }
Roland McGrathc269f192008-01-30 13:31:48 +01001418
1419 out_put_task_struct:
1420 put_task_struct(child);
1421 out:
Roland McGrathc269f192008-01-30 13:31:48 +01001422 return ret;
1423}
Christoph Hellwig96b89362008-11-25 08:10:03 +01001424#endif /* CONFIG_COMPAT */