1 #ifndef _LINUX_PTRACE_H
2 #define _LINUX_PTRACE_H
3
4 #include <linux/compiler.h> /* For unlikely. */
5 #include <linux/sched.h> /* For struct task_struct. */
6 #include <linux/err.h> /* for IS_ERR_VALUE */
7 #include <linux/bug.h> /* For BUG_ON. */
8 #include <linux/pid_namespace.h> /* For task_active_pid_ns. */
9 #include <uapi/linux/ptrace.h>
10
11 extern int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
12 void *buf, int len, unsigned int gup_flags);
13
14 /*
15 * Ptrace flags
16 *
17 * The owner ship rules for task->ptrace which holds the ptrace
18 * flags is simple. When a task is running it owns it's task->ptrace
19 * flags. When the a task is stopped the ptracer owns task->ptrace.
20 */
21
22 #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
23 #define PT_PTRACED 0x00000001
24 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
25
26 #define PT_OPT_FLAG_SHIFT 3
27 /* PT_TRACE_* event enable flags */
28 #define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
29 #define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
30 #define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
31 #define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
32 #define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
33 #define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
34 #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
35 #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
36 #define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
37
38 #define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
39 #define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
40
41 /* single stepping state bits (used on ARM and PA-RISC) */
42 #define PT_SINGLESTEP_BIT 31
43 #define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
44 #define PT_BLOCKSTEP_BIT 30
45 #define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
46
47 extern long arch_ptrace(struct task_struct *child, long request,
48 unsigned long addr, unsigned long data);
49 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
50 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
51 extern void ptrace_disable(struct task_struct *);
52 extern int ptrace_request(struct task_struct *child, long request,
53 unsigned long addr, unsigned long data);
54 extern void ptrace_notify(int exit_code);
55 extern void __ptrace_link(struct task_struct *child,
56 struct task_struct *new_parent);
57 extern void __ptrace_unlink(struct task_struct *child);
58 extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
59 #define PTRACE_MODE_READ 0x01
60 #define PTRACE_MODE_ATTACH 0x02
61 #define PTRACE_MODE_NOAUDIT 0x04
62 #define PTRACE_MODE_FSCREDS 0x08
63 #define PTRACE_MODE_REALCREDS 0x10
64
65 /* shorthands for READ/ATTACH and FSCREDS/REALCREDS combinations */
66 #define PTRACE_MODE_READ_FSCREDS (PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)
67 #define PTRACE_MODE_READ_REALCREDS (PTRACE_MODE_READ | PTRACE_MODE_REALCREDS)
68 #define PTRACE_MODE_ATTACH_FSCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_FSCREDS)
69 #define PTRACE_MODE_ATTACH_REALCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_REALCREDS)
70
71 /**
72 * ptrace_may_access - check whether the caller is permitted to access
73 * a target task.
74 * @task: target task
75 * @mode: selects type of access and caller credentials
76 *
77 * Returns true on success, false on denial.
78 *
79 * One of the flags PTRACE_MODE_FSCREDS and PTRACE_MODE_REALCREDS must
80 * be set in @mode to specify whether the access was requested through
81 * a filesystem syscall (should use effective capabilities and fsuid
82 * of the caller) or through an explicit syscall such as
83 * process_vm_writev or ptrace (and should use the real credentials).
84 */
85 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
86
87 static inline int ptrace_reparented(struct task_struct *child)
88 {
89 return !same_thread_group(child->real_parent, child->parent);
90 }
91
92 static inline void ptrace_unlink(struct task_struct *child)
93 {
94 if (unlikely(child->ptrace))
95 __ptrace_unlink(child);
96 }
97
98 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
99 unsigned long data);
100 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
101 unsigned long data);
102
103 /**
104 * ptrace_parent - return the task that is tracing the given task
105 * @task: task to consider
106 *
107 * Returns %NULL if no one is tracing @task, or the &struct task_struct
108 * pointer to its tracer.
109 *
110 * Must called under rcu_read_lock(). The pointer returned might be kept
111 * live only by RCU. During exec, this may be called with task_lock() held
112 * on @task, still held from when check_unsafe_exec() was called.
113 */
114 static inline struct task_struct *ptrace_parent(struct task_struct *task)
115 {
116 if (unlikely(task->ptrace))
117 return rcu_dereference(task->parent);
118 return NULL;
119 }
120
121 /**
122 * ptrace_event_enabled - test whether a ptrace event is enabled
123 * @task: ptracee of interest
124 * @event: %PTRACE_EVENT_* to test
125 *
126 * Test whether @event is enabled for ptracee @task.
127 *
128 * Returns %true if @event is enabled, %false otherwise.
129 */
130 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
131 {
132 return task->ptrace & PT_EVENT_FLAG(event);
133 }
134
135 /**
136 * ptrace_event - possibly stop for a ptrace event notification
137 * @event: %PTRACE_EVENT_* value to report
138 * @message: value for %PTRACE_GETEVENTMSG to return
139 *
140 * Check whether @event is enabled and, if so, report @event and @message
141 * to the ptrace parent.
142 *
143 * Called without locks.
144 */
145 static inline void ptrace_event(int event, unsigned long message)
146 {
147 if (unlikely(ptrace_event_enabled(current, event))) {
148 current->ptrace_message = message;
149 ptrace_notify((event << 8) | SIGTRAP);
150 } else if (event == PTRACE_EVENT_EXEC) {
151 /* legacy EXEC report via SIGTRAP */
152 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
153 send_sig(SIGTRAP, current, 0);
154 }
155 }
156
157 /**
158 * ptrace_event_pid - possibly stop for a ptrace event notification
159 * @event: %PTRACE_EVENT_* value to report
160 * @pid: process identifier for %PTRACE_GETEVENTMSG to return
161 *
162 * Check whether @event is enabled and, if so, report @event and @pid
163 * to the ptrace parent. @pid is reported as the pid_t seen from the
164 * the ptrace parent's pid namespace.
165 *
166 * Called without locks.
167 */
168 static inline void ptrace_event_pid(int event, struct pid *pid)
169 {
170 /*
171 * FIXME: There's a potential race if a ptracer in a different pid
172 * namespace than parent attaches between computing message below and
173 * when we acquire tasklist_lock in ptrace_stop(). If this happens,
174 * the ptracer will get a bogus pid from PTRACE_GETEVENTMSG.
175 */
176 unsigned long message = 0;
177 struct pid_namespace *ns;
178
179 rcu_read_lock();
180 ns = task_active_pid_ns(rcu_dereference(current->parent));
181 if (ns)
182 message = pid_nr_ns(pid, ns);
183 rcu_read_unlock();
184
185 ptrace_event(event, message);
186 }
187
188 /**
189 * ptrace_init_task - initialize ptrace state for a new child
190 * @child: new child task
191 * @ptrace: true if child should be ptrace'd by parent's tracer
192 *
193 * This is called immediately after adding @child to its parent's children
194 * list. @ptrace is false in the normal case, and true to ptrace @child.
195 *
196 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
197 */
198 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
199 {
200 INIT_LIST_HEAD(&child->ptrace_entry);
201 INIT_LIST_HEAD(&child->ptraced);
202 child->jobctl = 0;
203 child->ptrace = 0;
204 child->parent = child->real_parent;
205
206 if (unlikely(ptrace) && current->ptrace) {
207 child->ptrace = current->ptrace;
208 __ptrace_link(child, current->parent);
209
210 if (child->ptrace & PT_SEIZED)
211 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
212 else
213 sigaddset(&child->pending.signal, SIGSTOP);
214
215 set_tsk_thread_flag(child, TIF_SIGPENDING);
216 }
217 }
218
219 /**
220 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
221 * @task: task in %EXIT_DEAD state
222 *
223 * Called with write_lock(&tasklist_lock) held.
224 */
225 static inline void ptrace_release_task(struct task_struct *task)
226 {
227 BUG_ON(!list_empty(&task->ptraced));
228 ptrace_unlink(task);
229 BUG_ON(!list_empty(&task->ptrace_entry));
230 }
231
232 #ifndef force_successful_syscall_return
233 /*
234 * System call handlers that, upon successful completion, need to return a
235 * negative value should call force_successful_syscall_return() right before
236 * returning. On architectures where the syscall convention provides for a
237 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
238 * others), this macro can be used to ensure that the error flag will not get
239 * set. On architectures which do not support a separate error flag, the macro
240 * is a no-op and the spurious error condition needs to be filtered out by some
241 * other means (e.g., in user-level, by passing an extra argument to the
242 * syscall handler, or something along those lines).
243 */
244 #define force_successful_syscall_return() do { } while (0)
245 #endif
246
247 #ifndef is_syscall_success
248 /*
249 * On most systems we can tell if a syscall is a success based on if the retval
250 * is an error value. On some systems like ia64 and powerpc they have different
251 * indicators of success/failure and must define their own.
252 */
253 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
254 #endif
255
256 /*
257 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
258 *
259 * These do-nothing inlines are used when the arch does not
260 * implement single-step. The kerneldoc comments are here
261 * to document the interface for all arch definitions.
262 */
263
264 #ifndef arch_has_single_step
265 /**
266 * arch_has_single_step - does this CPU support user-mode single-step?
267 *
268 * If this is defined, then there must be function declarations or
269 * inlines for user_enable_single_step() and user_disable_single_step().
270 * arch_has_single_step() should evaluate to nonzero iff the machine
271 * supports instruction single-step for user mode.
272 * It can be a constant or it can test a CPU feature bit.
273 */
274 #define arch_has_single_step() (0)
275
276 /**
277 * user_enable_single_step - single-step in user-mode task
278 * @task: either current or a task stopped in %TASK_TRACED
279 *
280 * This can only be called when arch_has_single_step() has returned nonzero.
281 * Set @task so that when it returns to user mode, it will trap after the
282 * next single instruction executes. If arch_has_block_step() is defined,
283 * this must clear the effects of user_enable_block_step() too.
284 */
285 static inline void user_enable_single_step(struct task_struct *task)
286 {
287 BUG(); /* This can never be called. */
288 }
289
290 /**
291 * user_disable_single_step - cancel user-mode single-step
292 * @task: either current or a task stopped in %TASK_TRACED
293 *
294 * Clear @task of the effects of user_enable_single_step() and
295 * user_enable_block_step(). This can be called whether or not either
296 * of those was ever called on @task, and even if arch_has_single_step()
297 * returned zero.
298 */
299 static inline void user_disable_single_step(struct task_struct *task)
300 {
301 }
302 #else
303 extern void user_enable_single_step(struct task_struct *);
304 extern void user_disable_single_step(struct task_struct *);
305 #endif /* arch_has_single_step */
306
307 #ifndef arch_has_block_step
308 /**
309 * arch_has_block_step - does this CPU support user-mode block-step?
310 *
311 * If this is defined, then there must be a function declaration or inline
312 * for user_enable_block_step(), and arch_has_single_step() must be defined
313 * too. arch_has_block_step() should evaluate to nonzero iff the machine
314 * supports step-until-branch for user mode. It can be a constant or it
315 * can test a CPU feature bit.
316 */
317 #define arch_has_block_step() (0)
318
319 /**
320 * user_enable_block_step - step until branch in user-mode task
321 * @task: either current or a task stopped in %TASK_TRACED
322 *
323 * This can only be called when arch_has_block_step() has returned nonzero,
324 * and will never be called when single-instruction stepping is being used.
325 * Set @task so that when it returns to user mode, it will trap after the
326 * next branch or trap taken.
327 */
328 static inline void user_enable_block_step(struct task_struct *task)
329 {
330 BUG(); /* This can never be called. */
331 }
332 #else
333 extern void user_enable_block_step(struct task_struct *);
334 #endif /* arch_has_block_step */
335
336 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
337 extern void user_single_step_siginfo(struct task_struct *tsk,
338 struct pt_regs *regs, siginfo_t *info);
339 #else
340 static inline void user_single_step_siginfo(struct task_struct *tsk,
341 struct pt_regs *regs, siginfo_t *info)
342 {
343 memset(info, 0, sizeof(*info));
344 info->si_signo = SIGTRAP;
345 }
346 #endif
347
348 #ifndef arch_ptrace_stop_needed
349 /**
350 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
351 * @code: current->exit_code value ptrace will stop with
352 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
353 *
354 * This is called with the siglock held, to decide whether or not it's
355 * necessary to release the siglock and call arch_ptrace_stop() with the
356 * same @code and @info arguments. It can be defined to a constant if
357 * arch_ptrace_stop() is never required, or always is. On machines where
358 * this makes sense, it should be defined to a quick test to optimize out
359 * calling arch_ptrace_stop() when it would be superfluous. For example,
360 * if the thread has not been back to user mode since the last stop, the
361 * thread state might indicate that nothing needs to be done.
362 *
363 * This is guaranteed to be invoked once before a task stops for ptrace and
364 * may include arch-specific operations necessary prior to a ptrace stop.
365 */
366 #define arch_ptrace_stop_needed(code, info) (0)
367 #endif
368
369 #ifndef arch_ptrace_stop
370 /**
371 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
372 * @code: current->exit_code value ptrace will stop with
373 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
374 *
375 * This is called with no locks held when arch_ptrace_stop_needed() has
376 * just returned nonzero. It is allowed to block, e.g. for user memory
377 * access. The arch can have machine-specific work to be done before
378 * ptrace stops. On ia64, register backing store gets written back to user
379 * memory here. Since this can be costly (requires dropping the siglock),
380 * we only do it when the arch requires it for this particular stop, as
381 * indicated by arch_ptrace_stop_needed().
382 */
383 #define arch_ptrace_stop(code, info) do { } while (0)
384 #endif
385
386 #ifndef current_pt_regs
387 #define current_pt_regs() task_pt_regs(current)
388 #endif
389
390 #ifndef ptrace_signal_deliver
391 #define ptrace_signal_deliver() ((void)0)
392 #endif
393
394 /*
395 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
396 * on *all* architectures; the only reason to have a per-arch definition
397 * is optimisation.
398 */
399 #ifndef signal_pt_regs
400 #define signal_pt_regs() task_pt_regs(current)
401 #endif
402
403 #ifndef current_user_stack_pointer
404 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
405 #endif
406
407 extern int task_current_syscall(struct task_struct *target, long *callno,
408 unsigned long args[6], unsigned int maxargs,
409 unsigned long *sp, unsigned long *pc);
410
411 #endif
412
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