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#define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */ 23 24#define PT_OPT_FLAG_SHIFT 3 25/* PT_TRACE_* event enable flags */ 26#define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event))) 27#define PT_TRACESYSGOOD PT_EVENT_FLAG(0) 28#define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK) 29#define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK) 30#define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE) 31#define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC) 32#define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE) 33#define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT) 34#define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP) 35 36#define PT_EXITKILL (PTRACE_O_EXITKILL << 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 44extern long arch_ptrace(struct task_struct *child, long request, 45 unsigned long addr, unsigned long data); 46extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len); 47extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len); 48extern void ptrace_disable(struct task_struct *); 49extern int ptrace_request(struct task_struct *child, long request, 50 unsigned long addr, unsigned long data); 51extern void ptrace_notify(int exit_code); 52extern void __ptrace_link(struct task_struct *child, 53 struct task_struct *new_parent); 54extern void __ptrace_unlink(struct task_struct *child); 55extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead); 56#define PTRACE_MODE_READ 0x01 57#define PTRACE_MODE_ATTACH 0x02 58#define PTRACE_MODE_NOAUDIT 0x04 59#define PTRACE_MODE_FSCREDS 0x08 60#define PTRACE_MODE_REALCREDS 0x10 61 62/* shorthands for READ/ATTACH and FSCREDS/REALCREDS combinations */ 63#define PTRACE_MODE_READ_FSCREDS (PTRACE_MODE_READ | PTRACE_MODE_FSCREDS) 64#define PTRACE_MODE_READ_REALCREDS (PTRACE_MODE_READ | PTRACE_MODE_REALCREDS) 65#define PTRACE_MODE_ATTACH_FSCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_FSCREDS) 66#define PTRACE_MODE_ATTACH_REALCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_REALCREDS) 67 68/** 69 * ptrace_may_access - check whether the caller is permitted to access 70 * a target task. 71 * @task: target task 72 * @mode: selects type of access and caller credentials 73 * 74 * Returns true on success, false on denial. 75 * 76 * One of the flags PTRACE_MODE_FSCREDS and PTRACE_MODE_REALCREDS must 77 * be set in @mode to specify whether the access was requested through 78 * a filesystem syscall (should use effective capabilities and fsuid 79 * of the caller) or through an explicit syscall such as 80 * process_vm_writev or ptrace (and should use the real credentials). 81 */ 82extern bool ptrace_may_access(struct task_struct *task, unsigned int mode); 83 84static inline int ptrace_reparented(struct task_struct *child) 85{ 86 return !same_thread_group(child->real_parent, child->parent); 87} 88 89static inline void ptrace_unlink(struct task_struct *child) 90{ 91 if (unlikely(child->ptrace)) 92 __ptrace_unlink(child); 93} 94 95int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 96 unsigned long data); 97int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, 98 unsigned long data); 99 100/** 101 * ptrace_parent - return the task that is tracing the given task 102 * @task: task to consider 103 * 104 * Returns %NULL if no one is tracing @task, or the &struct task_struct 105 * pointer to its tracer. 106 * 107 * Must called under rcu_read_lock(). The pointer returned might be kept 108 * live only by RCU. During exec, this may be called with task_lock() held 109 * on @task, still held from when check_unsafe_exec() was called. 110 */ 111static inline struct task_struct *ptrace_parent(struct task_struct *task) 112{ 113 if (unlikely(task->ptrace)) 114 return rcu_dereference(task->parent); 115 return NULL; 116} 117 118/** 119 * ptrace_event_enabled - test whether a ptrace event is enabled 120 * @task: ptracee of interest 121 * @event: %PTRACE_EVENT_* to test 122 * 123 * Test whether @event is enabled for ptracee @task. 124 * 125 * Returns %true if @event is enabled, %false otherwise. 126 */ 127static inline bool ptrace_event_enabled(struct task_struct *task, int event) 128{ 129 return task->ptrace & PT_EVENT_FLAG(event); 130} 131 132/** 133 * ptrace_event - possibly stop for a ptrace event notification 134 * @event: %PTRACE_EVENT_* value to report 135 * @message: value for %PTRACE_GETEVENTMSG to return 136 * 137 * Check whether @event is enabled and, if so, report @event and @message 138 * to the ptrace parent. 139 * 140 * Called without locks. 141 */ 142static inline void ptrace_event(int event, unsigned long message) 143{ 144 if (unlikely(ptrace_event_enabled(current, event))) { 145 current->ptrace_message = message; 146 ptrace_notify((event << 8) | SIGTRAP); 147 } else if (event == PTRACE_EVENT_EXEC) { 148 /* legacy EXEC report via SIGTRAP */ 149 if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED) 150 send_sig(SIGTRAP, current, 0); 151 } 152} 153 154/** 155 * ptrace_event_pid - possibly stop for a ptrace event notification 156 * @event: %PTRACE_EVENT_* value to report 157 * @pid: process identifier for %PTRACE_GETEVENTMSG to return 158 * 159 * Check whether @event is enabled and, if so, report @event and @pid 160 * to the ptrace parent. @pid is reported as the pid_t seen from the 161 * the ptrace parent's pid namespace. 162 * 163 * Called without locks. 164 */ 165static inline void ptrace_event_pid(int event, struct pid *pid) 166{ 167 /* 168 * FIXME: There's a potential race if a ptracer in a different pid 169 * namespace than parent attaches between computing message below and 170 * when we acquire tasklist_lock in ptrace_stop(). If this happens, 171 * the ptracer will get a bogus pid from PTRACE_GETEVENTMSG. 172 */ 173 unsigned long message = 0; 174 struct pid_namespace *ns; 175 176 rcu_read_lock(); 177 ns = task_active_pid_ns(rcu_dereference(current->parent)); 178 if (ns) 179 message = pid_nr_ns(pid, ns); 180 rcu_read_unlock(); 181 182 ptrace_event(event, message); 183} 184 185/** 186 * ptrace_init_task - initialize ptrace state for a new child 187 * @child: new child task 188 * @ptrace: true if child should be ptrace'd by parent's tracer 189 * 190 * This is called immediately after adding @child to its parent's children 191 * list. @ptrace is false in the normal case, and true to ptrace @child. 192 * 193 * Called with current's siglock and write_lock_irq(&tasklist_lock) held. 194 */ 195static inline void ptrace_init_task(struct task_struct *child, bool ptrace) 196{ 197 INIT_LIST_HEAD(&child->ptrace_entry); 198 INIT_LIST_HEAD(&child->ptraced); 199 child->jobctl = 0; 200 child->ptrace = 0; 201 child->parent = child->real_parent; 202 203 if (unlikely(ptrace) && current->ptrace) { 204 child->ptrace = current->ptrace; 205 __ptrace_link(child, current->parent); 206 207 if (child->ptrace & PT_SEIZED) 208 task_set_jobctl_pending(child, JOBCTL_TRAP_STOP); 209 else 210 sigaddset(&child->pending.signal, SIGSTOP); 211 212 set_tsk_thread_flag(child, TIF_SIGPENDING); 213 } 214} 215 216/** 217 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped 218 * @task: task in %EXIT_DEAD state 219 * 220 * Called with write_lock(&tasklist_lock) held. 221 */ 222static inline void ptrace_release_task(struct task_struct *task) 223{ 224 BUG_ON(!list_empty(&task->ptraced)); 225 ptrace_unlink(task); 226 BUG_ON(!list_empty(&task->ptrace_entry)); 227} 228 229#ifndef force_successful_syscall_return 230/* 231 * System call handlers that, upon successful completion, need to return a 232 * negative value should call force_successful_syscall_return() right before 233 * returning. On architectures where the syscall convention provides for a 234 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly 235 * others), this macro can be used to ensure that the error flag will not get 236 * set. On architectures which do not support a separate error flag, the macro 237 * is a no-op and the spurious error condition needs to be filtered out by some 238 * other means (e.g., in user-level, by passing an extra argument to the 239 * syscall handler, or something along those lines). 240 */ 241#define force_successful_syscall_return() do { } while (0) 242#endif 243 244#ifndef is_syscall_success 245/* 246 * On most systems we can tell if a syscall is a success based on if the retval 247 * is an error value. On some systems like ia64 and powerpc they have different 248 * indicators of success/failure and must define their own. 249 */ 250#define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs)))) 251#endif 252 253/* 254 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__. 255 * 256 * These do-nothing inlines are used when the arch does not 257 * implement single-step. The kerneldoc comments are here 258 * to document the interface for all arch definitions. 259 */ 260 261#ifndef arch_has_single_step 262/** 263 * arch_has_single_step - does this CPU support user-mode single-step? 264 * 265 * If this is defined, then there must be function declarations or 266 * inlines for user_enable_single_step() and user_disable_single_step(). 267 * arch_has_single_step() should evaluate to nonzero iff the machine 268 * supports instruction single-step for user mode. 269 * It can be a constant or it can test a CPU feature bit. 270 */ 271#define arch_has_single_step() (0) 272 273/** 274 * user_enable_single_step - single-step in user-mode task 275 * @task: either current or a task stopped in %TASK_TRACED 276 * 277 * This can only be called when arch_has_single_step() has returned nonzero. 278 * Set @task so that when it returns to user mode, it will trap after the 279 * next single instruction executes. If arch_has_block_step() is defined, 280 * this must clear the effects of user_enable_block_step() too. 281 */ 282static inline void user_enable_single_step(struct task_struct *task) 283{ 284 BUG(); /* This can never be called. */ 285} 286 287/** 288 * user_disable_single_step - cancel user-mode single-step 289 * @task: either current or a task stopped in %TASK_TRACED 290 * 291 * Clear @task of the effects of user_enable_single_step() and 292 * user_enable_block_step(). This can be called whether or not either 293 * of those was ever called on @task, and even if arch_has_single_step() 294 * returned zero. 295 */ 296static inline void user_disable_single_step(struct task_struct *task) 297{ 298} 299#else 300extern void user_enable_single_step(struct task_struct *); 301extern void user_disable_single_step(struct task_struct *); 302#endif /* arch_has_single_step */ 303 304#ifndef arch_has_block_step 305/** 306 * arch_has_block_step - does this CPU support user-mode block-step? 307 * 308 * If this is defined, then there must be a function declaration or inline 309 * for user_enable_block_step(), and arch_has_single_step() must be defined 310 * too. arch_has_block_step() should evaluate to nonzero iff the machine 311 * supports step-until-branch for user mode. It can be a constant or it 312 * can test a CPU feature bit. 313 */ 314#define arch_has_block_step() (0) 315 316/** 317 * user_enable_block_step - step until branch in user-mode task 318 * @task: either current or a task stopped in %TASK_TRACED 319 * 320 * This can only be called when arch_has_block_step() has returned nonzero, 321 * and will never be called when single-instruction stepping is being used. 322 * Set @task so that when it returns to user mode, it will trap after the 323 * next branch or trap taken. 324 */ 325static inline void user_enable_block_step(struct task_struct *task) 326{ 327 BUG(); /* This can never be called. */ 328} 329#else 330extern void user_enable_block_step(struct task_struct *); 331#endif /* arch_has_block_step */ 332 333#ifdef ARCH_HAS_USER_SINGLE_STEP_INFO 334extern void user_single_step_siginfo(struct task_struct *tsk, 335 struct pt_regs *regs, siginfo_t *info); 336#else 337static inline void user_single_step_siginfo(struct task_struct *tsk, 338 struct pt_regs *regs, siginfo_t *info) 339{ 340 memset(info, 0, sizeof(*info)); 341 info->si_signo = SIGTRAP; 342} 343#endif 344 345#ifndef arch_ptrace_stop_needed 346/** 347 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called 348 * @code: current->exit_code value ptrace will stop with 349 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with 350 * 351 * This is called with the siglock held, to decide whether or not it's 352 * necessary to release the siglock and call arch_ptrace_stop() with the 353 * same @code and @info arguments. It can be defined to a constant if 354 * arch_ptrace_stop() is never required, or always is. On machines where 355 * this makes sense, it should be defined to a quick test to optimize out 356 * calling arch_ptrace_stop() when it would be superfluous. For example, 357 * if the thread has not been back to user mode since the last stop, the 358 * thread state might indicate that nothing needs to be done. 359 * 360 * This is guaranteed to be invoked once before a task stops for ptrace and 361 * may include arch-specific operations necessary prior to a ptrace stop. 362 */ 363#define arch_ptrace_stop_needed(code, info) (0) 364#endif 365 366#ifndef arch_ptrace_stop 367/** 368 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace 369 * @code: current->exit_code value ptrace will stop with 370 * @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with 371 * 372 * This is called with no locks held when arch_ptrace_stop_needed() has 373 * just returned nonzero. It is allowed to block, e.g. for user memory 374 * access. The arch can have machine-specific work to be done before 375 * ptrace stops. On ia64, register backing store gets written back to user 376 * memory here. Since this can be costly (requires dropping the siglock), 377 * we only do it when the arch requires it for this particular stop, as 378 * indicated by arch_ptrace_stop_needed(). 379 */ 380#define arch_ptrace_stop(code, info) do { } while (0) 381#endif 382 383#ifndef current_pt_regs 384#define current_pt_regs() task_pt_regs(current) 385#endif 386 387#ifndef ptrace_signal_deliver 388#define ptrace_signal_deliver() ((void)0) 389#endif 390 391/* 392 * unlike current_pt_regs(), this one is equal to task_pt_regs(current) 393 * on *all* architectures; the only reason to have a per-arch definition 394 * is optimisation. 395 */ 396#ifndef signal_pt_regs 397#define signal_pt_regs() task_pt_regs(current) 398#endif 399 400#ifndef current_user_stack_pointer 401#define current_user_stack_pointer() user_stack_pointer(current_pt_regs()) 402#endif 403 404extern int task_current_syscall(struct task_struct *target, long *callno, 405 unsigned long args[6], unsigned int maxargs, 406 unsigned long *sp, unsigned long *pc); 407 408#endif 409