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1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_PTRACE_H
3 #define _LINUX_PTRACE_H
5 #include <linux/compiler.h> /* For unlikely. */
6 #include <linux/sched.h> /* For struct task_struct. */
7 #include <linux/sched/signal.h> /* For send_sig(), same_thread_group(), etc. */
8 #include <linux/err.h> /* for IS_ERR_VALUE */
9 #include <linux/bug.h> /* For BUG_ON. */
10 #include <linux/pid_namespace.h> /* For task_active_pid_ns. */
11 #include <uapi/linux/ptrace.h>
12 #include <linux/seccomp.h>
14 /* Add sp to seccomp_data, as seccomp is user API, we don't want to modify it */
17 struct seccomp_data data
;
20 extern int ptrace_access_vm(struct task_struct
*tsk
, unsigned long addr
,
21 void *buf
, int len
, unsigned int gup_flags
);
26 * The owner ship rules for task->ptrace which holds the ptrace
27 * flags is simple. When a task is running it owns it's task->ptrace
28 * flags. When the a task is stopped the ptracer owns task->ptrace.
31 #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
32 #define PT_PTRACED 0x00000001
33 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
35 #define PT_OPT_FLAG_SHIFT 3
36 /* PT_TRACE_* event enable flags */
37 #define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
38 #define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
39 #define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
40 #define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
41 #define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
42 #define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
43 #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
44 #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
45 #define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
47 #define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
48 #define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
50 /* single stepping state bits (used on ARM and PA-RISC) */
51 #define PT_SINGLESTEP_BIT 31
52 #define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
53 #define PT_BLOCKSTEP_BIT 30
54 #define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
56 extern long arch_ptrace(struct task_struct
*child
, long request
,
57 unsigned long addr
, unsigned long data
);
58 extern int ptrace_readdata(struct task_struct
*tsk
, unsigned long src
, char __user
*dst
, int len
);
59 extern int ptrace_writedata(struct task_struct
*tsk
, char __user
*src
, unsigned long dst
, int len
);
60 extern void ptrace_disable(struct task_struct
*);
61 extern int ptrace_request(struct task_struct
*child
, long request
,
62 unsigned long addr
, unsigned long data
);
63 extern void ptrace_notify(int exit_code
);
64 extern void __ptrace_link(struct task_struct
*child
,
65 struct task_struct
*new_parent
,
66 const struct cred
*ptracer_cred
);
67 extern void __ptrace_unlink(struct task_struct
*child
);
68 extern void exit_ptrace(struct task_struct
*tracer
, struct list_head
*dead
);
69 #define PTRACE_MODE_READ 0x01
70 #define PTRACE_MODE_ATTACH 0x02
71 #define PTRACE_MODE_NOAUDIT 0x04
72 #define PTRACE_MODE_FSCREDS 0x08
73 #define PTRACE_MODE_REALCREDS 0x10
75 /* shorthands for READ/ATTACH and FSCREDS/REALCREDS combinations */
76 #define PTRACE_MODE_READ_FSCREDS (PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)
77 #define PTRACE_MODE_READ_REALCREDS (PTRACE_MODE_READ | PTRACE_MODE_REALCREDS)
78 #define PTRACE_MODE_ATTACH_FSCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_FSCREDS)
79 #define PTRACE_MODE_ATTACH_REALCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_REALCREDS)
82 * ptrace_may_access - check whether the caller is permitted to access
85 * @mode: selects type of access and caller credentials
87 * Returns true on success, false on denial.
89 * One of the flags PTRACE_MODE_FSCREDS and PTRACE_MODE_REALCREDS must
90 * be set in @mode to specify whether the access was requested through
91 * a filesystem syscall (should use effective capabilities and fsuid
92 * of the caller) or through an explicit syscall such as
93 * process_vm_writev or ptrace (and should use the real credentials).
95 extern bool ptrace_may_access(struct task_struct
*task
, unsigned int mode
);
97 static inline int ptrace_reparented(struct task_struct
*child
)
99 return !same_thread_group(child
->real_parent
, child
->parent
);
102 static inline void ptrace_unlink(struct task_struct
*child
)
104 if (unlikely(child
->ptrace
))
105 __ptrace_unlink(child
);
108 int generic_ptrace_peekdata(struct task_struct
*tsk
, unsigned long addr
,
110 int generic_ptrace_pokedata(struct task_struct
*tsk
, unsigned long addr
,
114 * ptrace_parent - return the task that is tracing the given task
115 * @task: task to consider
117 * Returns %NULL if no one is tracing @task, or the &struct task_struct
118 * pointer to its tracer.
120 * Must called under rcu_read_lock(). The pointer returned might be kept
121 * live only by RCU. During exec, this may be called with task_lock() held
122 * on @task, still held from when check_unsafe_exec() was called.
124 static inline struct task_struct
*ptrace_parent(struct task_struct
*task
)
126 if (unlikely(task
->ptrace
))
127 return rcu_dereference(task
->parent
);
132 * ptrace_event_enabled - test whether a ptrace event is enabled
133 * @task: ptracee of interest
134 * @event: %PTRACE_EVENT_* to test
136 * Test whether @event is enabled for ptracee @task.
138 * Returns %true if @event is enabled, %false otherwise.
140 static inline bool ptrace_event_enabled(struct task_struct
*task
, int event
)
142 return task
->ptrace
& PT_EVENT_FLAG(event
);
146 * ptrace_event - possibly stop for a ptrace event notification
147 * @event: %PTRACE_EVENT_* value to report
148 * @message: value for %PTRACE_GETEVENTMSG to return
150 * Check whether @event is enabled and, if so, report @event and @message
151 * to the ptrace parent.
153 * Called without locks.
155 static inline void ptrace_event(int event
, unsigned long message
)
157 if (unlikely(ptrace_event_enabled(current
, event
))) {
158 current
->ptrace_message
= message
;
159 ptrace_notify((event
<< 8) | SIGTRAP
);
160 } else if (event
== PTRACE_EVENT_EXEC
) {
161 /* legacy EXEC report via SIGTRAP */
162 if ((current
->ptrace
& (PT_PTRACED
|PT_SEIZED
)) == PT_PTRACED
)
163 send_sig(SIGTRAP
, current
, 0);
168 * ptrace_event_pid - possibly stop for a ptrace event notification
169 * @event: %PTRACE_EVENT_* value to report
170 * @pid: process identifier for %PTRACE_GETEVENTMSG to return
172 * Check whether @event is enabled and, if so, report @event and @pid
173 * to the ptrace parent. @pid is reported as the pid_t seen from the
174 * ptrace parent's pid namespace.
176 * Called without locks.
178 static inline void ptrace_event_pid(int event
, struct pid
*pid
)
181 * FIXME: There's a potential race if a ptracer in a different pid
182 * namespace than parent attaches between computing message below and
183 * when we acquire tasklist_lock in ptrace_stop(). If this happens,
184 * the ptracer will get a bogus pid from PTRACE_GETEVENTMSG.
186 unsigned long message
= 0;
187 struct pid_namespace
*ns
;
190 ns
= task_active_pid_ns(rcu_dereference(current
->parent
));
192 message
= pid_nr_ns(pid
, ns
);
195 ptrace_event(event
, message
);
199 * ptrace_init_task - initialize ptrace state for a new child
200 * @child: new child task
201 * @ptrace: true if child should be ptrace'd by parent's tracer
203 * This is called immediately after adding @child to its parent's children
204 * list. @ptrace is false in the normal case, and true to ptrace @child.
206 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
208 static inline void ptrace_init_task(struct task_struct
*child
, bool ptrace
)
210 INIT_LIST_HEAD(&child
->ptrace_entry
);
211 INIT_LIST_HEAD(&child
->ptraced
);
214 child
->parent
= child
->real_parent
;
216 if (unlikely(ptrace
) && current
->ptrace
) {
217 child
->ptrace
= current
->ptrace
;
218 __ptrace_link(child
, current
->parent
, current
->ptracer_cred
);
220 if (child
->ptrace
& PT_SEIZED
)
221 task_set_jobctl_pending(child
, JOBCTL_TRAP_STOP
);
223 sigaddset(&child
->pending
.signal
, SIGSTOP
);
226 child
->ptracer_cred
= NULL
;
230 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
231 * @task: task in %EXIT_DEAD state
233 * Called with write_lock(&tasklist_lock) held.
235 static inline void ptrace_release_task(struct task_struct
*task
)
237 BUG_ON(!list_empty(&task
->ptraced
));
239 BUG_ON(!list_empty(&task
->ptrace_entry
));
242 #ifndef force_successful_syscall_return
244 * System call handlers that, upon successful completion, need to return a
245 * negative value should call force_successful_syscall_return() right before
246 * returning. On architectures where the syscall convention provides for a
247 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
248 * others), this macro can be used to ensure that the error flag will not get
249 * set. On architectures which do not support a separate error flag, the macro
250 * is a no-op and the spurious error condition needs to be filtered out by some
251 * other means (e.g., in user-level, by passing an extra argument to the
252 * syscall handler, or something along those lines).
254 #define force_successful_syscall_return() do { } while (0)
257 #ifndef is_syscall_success
259 * On most systems we can tell if a syscall is a success based on if the retval
260 * is an error value. On some systems like ia64 and powerpc they have different
261 * indicators of success/failure and must define their own.
263 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
267 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
269 * These do-nothing inlines are used when the arch does not
270 * implement single-step. The kerneldoc comments are here
271 * to document the interface for all arch definitions.
274 #ifndef arch_has_single_step
276 * arch_has_single_step - does this CPU support user-mode single-step?
278 * If this is defined, then there must be function declarations or
279 * inlines for user_enable_single_step() and user_disable_single_step().
280 * arch_has_single_step() should evaluate to nonzero iff the machine
281 * supports instruction single-step for user mode.
282 * It can be a constant or it can test a CPU feature bit.
284 #define arch_has_single_step() (0)
287 * user_enable_single_step - single-step in user-mode task
288 * @task: either current or a task stopped in %TASK_TRACED
290 * This can only be called when arch_has_single_step() has returned nonzero.
291 * Set @task so that when it returns to user mode, it will trap after the
292 * next single instruction executes. If arch_has_block_step() is defined,
293 * this must clear the effects of user_enable_block_step() too.
295 static inline void user_enable_single_step(struct task_struct
*task
)
297 BUG(); /* This can never be called. */
301 * user_disable_single_step - cancel user-mode single-step
302 * @task: either current or a task stopped in %TASK_TRACED
304 * Clear @task of the effects of user_enable_single_step() and
305 * user_enable_block_step(). This can be called whether or not either
306 * of those was ever called on @task, and even if arch_has_single_step()
309 static inline void user_disable_single_step(struct task_struct
*task
)
313 extern void user_enable_single_step(struct task_struct
*);
314 extern void user_disable_single_step(struct task_struct
*);
315 #endif /* arch_has_single_step */
317 #ifndef arch_has_block_step
319 * arch_has_block_step - does this CPU support user-mode block-step?
321 * If this is defined, then there must be a function declaration or inline
322 * for user_enable_block_step(), and arch_has_single_step() must be defined
323 * too. arch_has_block_step() should evaluate to nonzero iff the machine
324 * supports step-until-branch for user mode. It can be a constant or it
325 * can test a CPU feature bit.
327 #define arch_has_block_step() (0)
330 * user_enable_block_step - step until branch in user-mode task
331 * @task: either current or a task stopped in %TASK_TRACED
333 * This can only be called when arch_has_block_step() has returned nonzero,
334 * and will never be called when single-instruction stepping is being used.
335 * Set @task so that when it returns to user mode, it will trap after the
336 * next branch or trap taken.
338 static inline void user_enable_block_step(struct task_struct
*task
)
340 BUG(); /* This can never be called. */
343 extern void user_enable_block_step(struct task_struct
*);
344 #endif /* arch_has_block_step */
346 #ifdef ARCH_HAS_USER_SINGLE_STEP_REPORT
347 extern void user_single_step_report(struct pt_regs
*regs
);
349 static inline void user_single_step_report(struct pt_regs
*regs
)
351 kernel_siginfo_t info
;
352 clear_siginfo(&info
);
353 info
.si_signo
= SIGTRAP
;
355 info
.si_code
= SI_USER
;
358 force_sig_info(&info
);
362 #ifndef arch_ptrace_stop_needed
364 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
365 * @code: current->exit_code value ptrace will stop with
366 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
368 * This is called with the siglock held, to decide whether or not it's
369 * necessary to release the siglock and call arch_ptrace_stop() with the
370 * same @code and @info arguments. It can be defined to a constant if
371 * arch_ptrace_stop() is never required, or always is. On machines where
372 * this makes sense, it should be defined to a quick test to optimize out
373 * calling arch_ptrace_stop() when it would be superfluous. For example,
374 * if the thread has not been back to user mode since the last stop, the
375 * thread state might indicate that nothing needs to be done.
377 * This is guaranteed to be invoked once before a task stops for ptrace and
378 * may include arch-specific operations necessary prior to a ptrace stop.
380 #define arch_ptrace_stop_needed(code, info) (0)
383 #ifndef arch_ptrace_stop
385 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
386 * @code: current->exit_code value ptrace will stop with
387 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
389 * This is called with no locks held when arch_ptrace_stop_needed() has
390 * just returned nonzero. It is allowed to block, e.g. for user memory
391 * access. The arch can have machine-specific work to be done before
392 * ptrace stops. On ia64, register backing store gets written back to user
393 * memory here. Since this can be costly (requires dropping the siglock),
394 * we only do it when the arch requires it for this particular stop, as
395 * indicated by arch_ptrace_stop_needed().
397 #define arch_ptrace_stop(code, info) do { } while (0)
400 #ifndef current_pt_regs
401 #define current_pt_regs() task_pt_regs(current)
405 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
406 * on *all* architectures; the only reason to have a per-arch definition
409 #ifndef signal_pt_regs
410 #define signal_pt_regs() task_pt_regs(current)
413 #ifndef current_user_stack_pointer
414 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
417 extern int task_current_syscall(struct task_struct
*target
, struct syscall_info
*info
);
419 extern void sigaction_compat_abi(struct k_sigaction
*act
, struct k_sigaction
*oact
);