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>
13 extern int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
14 void *buf, int len, unsigned int gup_flags);
19 * The owner ship rules for task->ptrace which holds the ptrace
20 * flags is simple. When a task is running it owns it's task->ptrace
21 * flags. When the a task is stopped the ptracer owns task->ptrace.
24 #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
25 #define PT_PTRACED 0x00000001
26 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
28 #define PT_OPT_FLAG_SHIFT 3
29 /* PT_TRACE_* event enable flags */
30 #define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
31 #define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
32 #define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
33 #define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
34 #define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
35 #define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
36 #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
37 #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
38 #define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
40 #define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
41 #define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
43 /* single stepping state bits (used on ARM and PA-RISC) */
44 #define PT_SINGLESTEP_BIT 31
45 #define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
46 #define PT_BLOCKSTEP_BIT 30
47 #define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
49 extern long arch_ptrace(struct task_struct *child, long request,
50 unsigned long addr, unsigned long data);
51 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
52 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
53 extern void ptrace_disable(struct task_struct *);
54 extern int ptrace_request(struct task_struct *child, long request,
55 unsigned long addr, unsigned long data);
56 extern void ptrace_notify(int exit_code);
57 extern void __ptrace_link(struct task_struct *child,
58 struct task_struct *new_parent,
59 const struct cred *ptracer_cred);
60 extern void __ptrace_unlink(struct task_struct *child);
61 extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
62 #define PTRACE_MODE_READ 0x01
63 #define PTRACE_MODE_ATTACH 0x02
64 #define PTRACE_MODE_NOAUDIT 0x04
65 #define PTRACE_MODE_FSCREDS 0x08
66 #define PTRACE_MODE_REALCREDS 0x10
67 #define PTRACE_MODE_SCHED 0x20
68 #define PTRACE_MODE_IBPB 0x40
70 /* shorthands for READ/ATTACH and FSCREDS/REALCREDS combinations */
71 #define PTRACE_MODE_READ_FSCREDS (PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)
72 #define PTRACE_MODE_READ_REALCREDS (PTRACE_MODE_READ | PTRACE_MODE_REALCREDS)
73 #define PTRACE_MODE_ATTACH_FSCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_FSCREDS)
74 #define PTRACE_MODE_ATTACH_REALCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_REALCREDS)
75 #define PTRACE_MODE_SPEC_IBPB (PTRACE_MODE_ATTACH_REALCREDS | PTRACE_MODE_IBPB)
78 * ptrace_may_access - check whether the caller is permitted to access
81 * @mode: selects type of access and caller credentials
83 * Returns true on success, false on denial.
85 * One of the flags PTRACE_MODE_FSCREDS and PTRACE_MODE_REALCREDS must
86 * be set in @mode to specify whether the access was requested through
87 * a filesystem syscall (should use effective capabilities and fsuid
88 * of the caller) or through an explicit syscall such as
89 * process_vm_writev or ptrace (and should use the real credentials).
91 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
94 * ptrace_may_access - check whether the caller is permitted to access
97 * @mode: selects type of access and caller credentials
99 * Returns true on success, false on denial.
101 * Similar to ptrace_may_access(). Only to be called from context switch
102 * code. Does not call into audit and the regular LSM hooks due to locking
105 extern bool ptrace_may_access_sched(struct task_struct *task, unsigned int mode);
107 static inline int ptrace_reparented(struct task_struct *child)
109 return !same_thread_group(child->real_parent, child->parent);
112 static inline void ptrace_unlink(struct task_struct *child)
114 if (unlikely(child->ptrace))
115 __ptrace_unlink(child);
118 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
120 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
124 * ptrace_parent - return the task that is tracing the given task
125 * @task: task to consider
127 * Returns %NULL if no one is tracing @task, or the &struct task_struct
128 * pointer to its tracer.
130 * Must called under rcu_read_lock(). The pointer returned might be kept
131 * live only by RCU. During exec, this may be called with task_lock() held
132 * on @task, still held from when check_unsafe_exec() was called.
134 static inline struct task_struct *ptrace_parent(struct task_struct *task)
136 if (unlikely(task->ptrace))
137 return rcu_dereference(task->parent);
142 * ptrace_event_enabled - test whether a ptrace event is enabled
143 * @task: ptracee of interest
144 * @event: %PTRACE_EVENT_* to test
146 * Test whether @event is enabled for ptracee @task.
148 * Returns %true if @event is enabled, %false otherwise.
150 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
152 return task->ptrace & PT_EVENT_FLAG(event);
156 * ptrace_event - possibly stop for a ptrace event notification
157 * @event: %PTRACE_EVENT_* value to report
158 * @message: value for %PTRACE_GETEVENTMSG to return
160 * Check whether @event is enabled and, if so, report @event and @message
161 * to the ptrace parent.
163 * Called without locks.
165 static inline void ptrace_event(int event, unsigned long message)
167 if (unlikely(ptrace_event_enabled(current, event))) {
168 current->ptrace_message = message;
169 ptrace_notify((event << 8) | SIGTRAP);
170 } else if (event == PTRACE_EVENT_EXEC) {
171 /* legacy EXEC report via SIGTRAP */
172 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
173 send_sig(SIGTRAP, current, 0);
178 * ptrace_event_pid - possibly stop for a ptrace event notification
179 * @event: %PTRACE_EVENT_* value to report
180 * @pid: process identifier for %PTRACE_GETEVENTMSG to return
182 * Check whether @event is enabled and, if so, report @event and @pid
183 * to the ptrace parent. @pid is reported as the pid_t seen from the
184 * the ptrace parent's pid namespace.
186 * Called without locks.
188 static inline void ptrace_event_pid(int event, struct pid *pid)
191 * FIXME: There's a potential race if a ptracer in a different pid
192 * namespace than parent attaches between computing message below and
193 * when we acquire tasklist_lock in ptrace_stop(). If this happens,
194 * the ptracer will get a bogus pid from PTRACE_GETEVENTMSG.
196 unsigned long message = 0;
197 struct pid_namespace *ns;
200 ns = task_active_pid_ns(rcu_dereference(current->parent));
202 message = pid_nr_ns(pid, ns);
205 ptrace_event(event, message);
209 * ptrace_init_task - initialize ptrace state for a new child
210 * @child: new child task
211 * @ptrace: true if child should be ptrace'd by parent's tracer
213 * This is called immediately after adding @child to its parent's children
214 * list. @ptrace is false in the normal case, and true to ptrace @child.
216 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
218 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
220 INIT_LIST_HEAD(&child->ptrace_entry);
221 INIT_LIST_HEAD(&child->ptraced);
224 child->parent = child->real_parent;
226 if (unlikely(ptrace) && current->ptrace) {
227 child->ptrace = current->ptrace;
228 __ptrace_link(child, current->parent, current->ptracer_cred);
230 if (child->ptrace & PT_SEIZED)
231 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
233 sigaddset(&child->pending.signal, SIGSTOP);
236 child->ptracer_cred = NULL;
240 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
241 * @task: task in %EXIT_DEAD state
243 * Called with write_lock(&tasklist_lock) held.
245 static inline void ptrace_release_task(struct task_struct *task)
247 BUG_ON(!list_empty(&task->ptraced));
249 BUG_ON(!list_empty(&task->ptrace_entry));
252 #ifndef force_successful_syscall_return
254 * System call handlers that, upon successful completion, need to return a
255 * negative value should call force_successful_syscall_return() right before
256 * returning. On architectures where the syscall convention provides for a
257 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
258 * others), this macro can be used to ensure that the error flag will not get
259 * set. On architectures which do not support a separate error flag, the macro
260 * is a no-op and the spurious error condition needs to be filtered out by some
261 * other means (e.g., in user-level, by passing an extra argument to the
262 * syscall handler, or something along those lines).
264 #define force_successful_syscall_return() do { } while (0)
267 #ifndef is_syscall_success
269 * On most systems we can tell if a syscall is a success based on if the retval
270 * is an error value. On some systems like ia64 and powerpc they have different
271 * indicators of success/failure and must define their own.
273 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
277 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
279 * These do-nothing inlines are used when the arch does not
280 * implement single-step. The kerneldoc comments are here
281 * to document the interface for all arch definitions.
284 #ifndef arch_has_single_step
286 * arch_has_single_step - does this CPU support user-mode single-step?
288 * If this is defined, then there must be function declarations or
289 * inlines for user_enable_single_step() and user_disable_single_step().
290 * arch_has_single_step() should evaluate to nonzero iff the machine
291 * supports instruction single-step for user mode.
292 * It can be a constant or it can test a CPU feature bit.
294 #define arch_has_single_step() (0)
297 * user_enable_single_step - single-step in user-mode task
298 * @task: either current or a task stopped in %TASK_TRACED
300 * This can only be called when arch_has_single_step() has returned nonzero.
301 * Set @task so that when it returns to user mode, it will trap after the
302 * next single instruction executes. If arch_has_block_step() is defined,
303 * this must clear the effects of user_enable_block_step() too.
305 static inline void user_enable_single_step(struct task_struct *task)
307 BUG(); /* This can never be called. */
311 * user_disable_single_step - cancel user-mode single-step
312 * @task: either current or a task stopped in %TASK_TRACED
314 * Clear @task of the effects of user_enable_single_step() and
315 * user_enable_block_step(). This can be called whether or not either
316 * of those was ever called on @task, and even if arch_has_single_step()
319 static inline void user_disable_single_step(struct task_struct *task)
323 extern void user_enable_single_step(struct task_struct *);
324 extern void user_disable_single_step(struct task_struct *);
325 #endif /* arch_has_single_step */
327 #ifndef arch_has_block_step
329 * arch_has_block_step - does this CPU support user-mode block-step?
331 * If this is defined, then there must be a function declaration or inline
332 * for user_enable_block_step(), and arch_has_single_step() must be defined
333 * too. arch_has_block_step() should evaluate to nonzero iff the machine
334 * supports step-until-branch for user mode. It can be a constant or it
335 * can test a CPU feature bit.
337 #define arch_has_block_step() (0)
340 * user_enable_block_step - step until branch in user-mode task
341 * @task: either current or a task stopped in %TASK_TRACED
343 * This can only be called when arch_has_block_step() has returned nonzero,
344 * and will never be called when single-instruction stepping is being used.
345 * Set @task so that when it returns to user mode, it will trap after the
346 * next branch or trap taken.
348 static inline void user_enable_block_step(struct task_struct *task)
350 BUG(); /* This can never be called. */
353 extern void user_enable_block_step(struct task_struct *);
354 #endif /* arch_has_block_step */
356 #ifdef ARCH_HAS_USER_SINGLE_STEP_REPORT
357 extern void user_single_step_report(struct pt_regs *regs);
359 static inline void user_single_step_report(struct pt_regs *regs)
361 kernel_siginfo_t info;
362 clear_siginfo(&info);
363 info.si_signo = SIGTRAP;
365 info.si_code = SI_USER;
368 force_sig_info(info.si_signo, &info, current);
372 #ifndef arch_ptrace_stop_needed
374 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
375 * @code: current->exit_code value ptrace will stop with
376 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
378 * This is called with the siglock held, to decide whether or not it's
379 * necessary to release the siglock and call arch_ptrace_stop() with the
380 * same @code and @info arguments. It can be defined to a constant if
381 * arch_ptrace_stop() is never required, or always is. On machines where
382 * this makes sense, it should be defined to a quick test to optimize out
383 * calling arch_ptrace_stop() when it would be superfluous. For example,
384 * if the thread has not been back to user mode since the last stop, the
385 * thread state might indicate that nothing needs to be done.
387 * This is guaranteed to be invoked once before a task stops for ptrace and
388 * may include arch-specific operations necessary prior to a ptrace stop.
390 #define arch_ptrace_stop_needed(code, info) (0)
393 #ifndef arch_ptrace_stop
395 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
396 * @code: current->exit_code value ptrace will stop with
397 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
399 * This is called with no locks held when arch_ptrace_stop_needed() has
400 * just returned nonzero. It is allowed to block, e.g. for user memory
401 * access. The arch can have machine-specific work to be done before
402 * ptrace stops. On ia64, register backing store gets written back to user
403 * memory here. Since this can be costly (requires dropping the siglock),
404 * we only do it when the arch requires it for this particular stop, as
405 * indicated by arch_ptrace_stop_needed().
407 #define arch_ptrace_stop(code, info) do { } while (0)
410 #ifndef current_pt_regs
411 #define current_pt_regs() task_pt_regs(current)
415 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
416 * on *all* architectures; the only reason to have a per-arch definition
419 #ifndef signal_pt_regs
420 #define signal_pt_regs() task_pt_regs(current)
423 #ifndef current_user_stack_pointer
424 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
427 extern int task_current_syscall(struct task_struct *target, long *callno,
428 unsigned long args[6], unsigned int maxargs,
429 unsigned long *sp, unsigned long *pc);