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 /*
12 * Ptrace flags
13 *
14 * The owner ship rules for task->ptrace which holds the ptrace
15 * flags is simple. When a task is running it owns it's task->ptrace
16 * flags. When the a task is stopped the ptracer owns task->ptrace.
17 */
18
19 #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
20 #define PT_PTRACED 0x00000001
21 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
22
23 #define PT_OPT_FLAG_SHIFT 3
24 /* PT_TRACE_* event enable flags */
25 #define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
26 #define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
27 #define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
28 #define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
29 #define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
30 #define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
31 #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
32 #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
33 #define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
34
35 #define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
36 #define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
37
38 /* single stepping state bits (used on ARM and PA-RISC) */
39 #define PT_SINGLESTEP_BIT 31
40 #define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
41 #define PT_BLOCKSTEP_BIT 30
42 #define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
43
44 extern long arch_ptrace(struct task_struct *child, long request,
45 unsigned long addr, unsigned long data);
46 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
47 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
48 extern void ptrace_disable(struct task_struct *);
49 extern int ptrace_request(struct task_struct *child, long request,
50 unsigned long addr, unsigned long data);
51 extern void ptrace_notify(int exit_code);
52 extern void __ptrace_link(struct task_struct *child,
53 struct task_struct *new_parent,
54 const struct cred *ptracer_cred);
55 extern void __ptrace_unlink(struct task_struct *child);
56 extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
57 #define PTRACE_MODE_READ 0x01
58 #define PTRACE_MODE_ATTACH 0x02
59 #define PTRACE_MODE_NOAUDIT 0x04
60 #define PTRACE_MODE_FSCREDS 0x08
61 #define PTRACE_MODE_REALCREDS 0x10
62 #define PTRACE_MODE_SCHED 0x20
63 #define PTRACE_MODE_IBPB 0x40
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 #define PTRACE_MODE_SPEC_IBPB (PTRACE_MODE_ATTACH_REALCREDS | PTRACE_MODE_IBPB)
71
72 /**
73 * ptrace_may_access - check whether the caller is permitted to access
74 * a target task.
75 * @task: target task
76 * @mode: selects type of access and caller credentials
77 *
78 * Returns true on success, false on denial.
79 *
80 * One of the flags PTRACE_MODE_FSCREDS and PTRACE_MODE_REALCREDS must
81 * be set in @mode to specify whether the access was requested through
82 * a filesystem syscall (should use effective capabilities and fsuid
83 * of the caller) or through an explicit syscall such as
84 * process_vm_writev or ptrace (and should use the real credentials).
85 */
86 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
87
88 /**
89 * ptrace_may_access - check whether the caller is permitted to access
90 * a target task.
91 * @task: target task
92 * @mode: selects type of access and caller credentials
93 *
94 * Returns true on success, false on denial.
95 *
96 * Similar to ptrace_may_access(). Only to be called from context switch
97 * code. Does not call into audit and the regular LSM hooks due to locking
98 * constraints.
99 */
100 extern bool ptrace_may_access_sched(struct task_struct *task, unsigned int mode);
101
ptrace_reparented(struct task_struct * child)102 static inline int ptrace_reparented(struct task_struct *child)
103 {
104 return !same_thread_group(child->real_parent, child->parent);
105 }
106
ptrace_unlink(struct task_struct * child)107 static inline void ptrace_unlink(struct task_struct *child)
108 {
109 if (unlikely(child->ptrace))
110 __ptrace_unlink(child);
111 }
112
113 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
114 unsigned long data);
115 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
116 unsigned long data);
117
118 /**
119 * ptrace_parent - return the task that is tracing the given task
120 * @task: task to consider
121 *
122 * Returns %NULL if no one is tracing @task, or the &struct task_struct
123 * pointer to its tracer.
124 *
125 * Must called under rcu_read_lock(). The pointer returned might be kept
126 * live only by RCU. During exec, this may be called with task_lock() held
127 * on @task, still held from when check_unsafe_exec() was called.
128 */
ptrace_parent(struct task_struct * task)129 static inline struct task_struct *ptrace_parent(struct task_struct *task)
130 {
131 if (unlikely(task->ptrace))
132 return rcu_dereference(task->parent);
133 return NULL;
134 }
135
136 /**
137 * ptrace_event_enabled - test whether a ptrace event is enabled
138 * @task: ptracee of interest
139 * @event: %PTRACE_EVENT_* to test
140 *
141 * Test whether @event is enabled for ptracee @task.
142 *
143 * Returns %true if @event is enabled, %false otherwise.
144 */
ptrace_event_enabled(struct task_struct * task,int event)145 static inline bool ptrace_event_enabled(struct task_struct *task, int event)
146 {
147 return task->ptrace & PT_EVENT_FLAG(event);
148 }
149
150 /**
151 * ptrace_event - possibly stop for a ptrace event notification
152 * @event: %PTRACE_EVENT_* value to report
153 * @message: value for %PTRACE_GETEVENTMSG to return
154 *
155 * Check whether @event is enabled and, if so, report @event and @message
156 * to the ptrace parent.
157 *
158 * Called without locks.
159 */
ptrace_event(int event,unsigned long message)160 static inline void ptrace_event(int event, unsigned long message)
161 {
162 if (unlikely(ptrace_event_enabled(current, event))) {
163 current->ptrace_message = message;
164 ptrace_notify((event << 8) | SIGTRAP);
165 } else if (event == PTRACE_EVENT_EXEC) {
166 /* legacy EXEC report via SIGTRAP */
167 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
168 send_sig(SIGTRAP, current, 0);
169 }
170 }
171
172 /**
173 * ptrace_event_pid - possibly stop for a ptrace event notification
174 * @event: %PTRACE_EVENT_* value to report
175 * @pid: process identifier for %PTRACE_GETEVENTMSG to return
176 *
177 * Check whether @event is enabled and, if so, report @event and @pid
178 * to the ptrace parent. @pid is reported as the pid_t seen from the
179 * the ptrace parent's pid namespace.
180 *
181 * Called without locks.
182 */
ptrace_event_pid(int event,struct pid * pid)183 static inline void ptrace_event_pid(int event, struct pid *pid)
184 {
185 /*
186 * FIXME: There's a potential race if a ptracer in a different pid
187 * namespace than parent attaches between computing message below and
188 * when we acquire tasklist_lock in ptrace_stop(). If this happens,
189 * the ptracer will get a bogus pid from PTRACE_GETEVENTMSG.
190 */
191 unsigned long message = 0;
192 struct pid_namespace *ns;
193
194 rcu_read_lock();
195 ns = task_active_pid_ns(rcu_dereference(current->parent));
196 if (ns)
197 message = pid_nr_ns(pid, ns);
198 rcu_read_unlock();
199
200 ptrace_event(event, message);
201 }
202
203 /**
204 * ptrace_init_task - initialize ptrace state for a new child
205 * @child: new child task
206 * @ptrace: true if child should be ptrace'd by parent's tracer
207 *
208 * This is called immediately after adding @child to its parent's children
209 * list. @ptrace is false in the normal case, and true to ptrace @child.
210 *
211 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
212 */
ptrace_init_task(struct task_struct * child,bool ptrace)213 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
214 {
215 INIT_LIST_HEAD(&child->ptrace_entry);
216 INIT_LIST_HEAD(&child->ptraced);
217 child->jobctl = 0;
218 child->ptrace = 0;
219 child->parent = child->real_parent;
220
221 if (unlikely(ptrace) && current->ptrace) {
222 child->ptrace = current->ptrace;
223 __ptrace_link(child, current->parent, current->ptracer_cred);
224
225 if (child->ptrace & PT_SEIZED)
226 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
227 else
228 sigaddset(&child->pending.signal, SIGSTOP);
229
230 set_tsk_thread_flag(child, TIF_SIGPENDING);
231 }
232 else
233 child->ptracer_cred = NULL;
234 }
235
236 /**
237 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
238 * @task: task in %EXIT_DEAD state
239 *
240 * Called with write_lock(&tasklist_lock) held.
241 */
ptrace_release_task(struct task_struct * task)242 static inline void ptrace_release_task(struct task_struct *task)
243 {
244 BUG_ON(!list_empty(&task->ptraced));
245 ptrace_unlink(task);
246 BUG_ON(!list_empty(&task->ptrace_entry));
247 }
248
249 #ifndef force_successful_syscall_return
250 /*
251 * System call handlers that, upon successful completion, need to return a
252 * negative value should call force_successful_syscall_return() right before
253 * returning. On architectures where the syscall convention provides for a
254 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
255 * others), this macro can be used to ensure that the error flag will not get
256 * set. On architectures which do not support a separate error flag, the macro
257 * is a no-op and the spurious error condition needs to be filtered out by some
258 * other means (e.g., in user-level, by passing an extra argument to the
259 * syscall handler, or something along those lines).
260 */
261 #define force_successful_syscall_return() do { } while (0)
262 #endif
263
264 #ifndef is_syscall_success
265 /*
266 * On most systems we can tell if a syscall is a success based on if the retval
267 * is an error value. On some systems like ia64 and powerpc they have different
268 * indicators of success/failure and must define their own.
269 */
270 #define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
271 #endif
272
273 /*
274 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
275 *
276 * These do-nothing inlines are used when the arch does not
277 * implement single-step. The kerneldoc comments are here
278 * to document the interface for all arch definitions.
279 */
280
281 #ifndef arch_has_single_step
282 /**
283 * arch_has_single_step - does this CPU support user-mode single-step?
284 *
285 * If this is defined, then there must be function declarations or
286 * inlines for user_enable_single_step() and user_disable_single_step().
287 * arch_has_single_step() should evaluate to nonzero iff the machine
288 * supports instruction single-step for user mode.
289 * It can be a constant or it can test a CPU feature bit.
290 */
291 #define arch_has_single_step() (0)
292
293 /**
294 * user_enable_single_step - single-step in user-mode task
295 * @task: either current or a task stopped in %TASK_TRACED
296 *
297 * This can only be called when arch_has_single_step() has returned nonzero.
298 * Set @task so that when it returns to user mode, it will trap after the
299 * next single instruction executes. If arch_has_block_step() is defined,
300 * this must clear the effects of user_enable_block_step() too.
301 */
user_enable_single_step(struct task_struct * task)302 static inline void user_enable_single_step(struct task_struct *task)
303 {
304 BUG(); /* This can never be called. */
305 }
306
307 /**
308 * user_disable_single_step - cancel user-mode single-step
309 * @task: either current or a task stopped in %TASK_TRACED
310 *
311 * Clear @task of the effects of user_enable_single_step() and
312 * user_enable_block_step(). This can be called whether or not either
313 * of those was ever called on @task, and even if arch_has_single_step()
314 * returned zero.
315 */
user_disable_single_step(struct task_struct * task)316 static inline void user_disable_single_step(struct task_struct *task)
317 {
318 }
319 #else
320 extern void user_enable_single_step(struct task_struct *);
321 extern void user_disable_single_step(struct task_struct *);
322 #endif /* arch_has_single_step */
323
324 #ifndef arch_has_block_step
325 /**
326 * arch_has_block_step - does this CPU support user-mode block-step?
327 *
328 * If this is defined, then there must be a function declaration or inline
329 * for user_enable_block_step(), and arch_has_single_step() must be defined
330 * too. arch_has_block_step() should evaluate to nonzero iff the machine
331 * supports step-until-branch for user mode. It can be a constant or it
332 * can test a CPU feature bit.
333 */
334 #define arch_has_block_step() (0)
335
336 /**
337 * user_enable_block_step - step until branch in user-mode task
338 * @task: either current or a task stopped in %TASK_TRACED
339 *
340 * This can only be called when arch_has_block_step() has returned nonzero,
341 * and will never be called when single-instruction stepping is being used.
342 * Set @task so that when it returns to user mode, it will trap after the
343 * next branch or trap taken.
344 */
user_enable_block_step(struct task_struct * task)345 static inline void user_enable_block_step(struct task_struct *task)
346 {
347 BUG(); /* This can never be called. */
348 }
349 #else
350 extern void user_enable_block_step(struct task_struct *);
351 #endif /* arch_has_block_step */
352
353 #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
354 extern void user_single_step_siginfo(struct task_struct *tsk,
355 struct pt_regs *regs, siginfo_t *info);
356 #else
user_single_step_siginfo(struct task_struct * tsk,struct pt_regs * regs,siginfo_t * info)357 static inline void user_single_step_siginfo(struct task_struct *tsk,
358 struct pt_regs *regs, siginfo_t *info)
359 {
360 memset(info, 0, sizeof(*info));
361 info->si_signo = SIGTRAP;
362 }
363 #endif
364
365 #ifndef arch_ptrace_stop_needed
366 /**
367 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
368 * @code: current->exit_code value ptrace will stop with
369 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
370 *
371 * This is called with the siglock held, to decide whether or not it's
372 * necessary to release the siglock and call arch_ptrace_stop() with the
373 * same @code and @info arguments. It can be defined to a constant if
374 * arch_ptrace_stop() is never required, or always is. On machines where
375 * this makes sense, it should be defined to a quick test to optimize out
376 * calling arch_ptrace_stop() when it would be superfluous. For example,
377 * if the thread has not been back to user mode since the last stop, the
378 * thread state might indicate that nothing needs to be done.
379 *
380 * This is guaranteed to be invoked once before a task stops for ptrace and
381 * may include arch-specific operations necessary prior to a ptrace stop.
382 */
383 #define arch_ptrace_stop_needed(code, info) (0)
384 #endif
385
386 #ifndef arch_ptrace_stop
387 /**
388 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
389 * @code: current->exit_code value ptrace will stop with
390 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
391 *
392 * This is called with no locks held when arch_ptrace_stop_needed() has
393 * just returned nonzero. It is allowed to block, e.g. for user memory
394 * access. The arch can have machine-specific work to be done before
395 * ptrace stops. On ia64, register backing store gets written back to user
396 * memory here. Since this can be costly (requires dropping the siglock),
397 * we only do it when the arch requires it for this particular stop, as
398 * indicated by arch_ptrace_stop_needed().
399 */
400 #define arch_ptrace_stop(code, info) do { } while (0)
401 #endif
402
403 #ifndef current_pt_regs
404 #define current_pt_regs() task_pt_regs(current)
405 #endif
406
407 #ifndef ptrace_signal_deliver
408 #define ptrace_signal_deliver() ((void)0)
409 #endif
410
411 /*
412 * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
413 * on *all* architectures; the only reason to have a per-arch definition
414 * is optimisation.
415 */
416 #ifndef signal_pt_regs
417 #define signal_pt_regs() task_pt_regs(current)
418 #endif
419
420 #ifndef current_user_stack_pointer
421 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
422 #endif
423
424 extern int task_current_syscall(struct task_struct *target, long *callno,
425 unsigned long args[6], unsigned int maxargs,
426 unsigned long *sp, unsigned long *pc);
427
428 #endif
429