/* * linux/kernel/ptrace.c * * (C) Copyright 1999 Linus Torvalds * * Common interfaces for "ptrace()" which we do not want * to continually duplicate across every architecture. */ #include <linux/capability.h>#include <linux/export.h>#include <linux/sched.h>#include <linux/errno.h>#include <linux/mm.h>#include <linux/highmem.h>#include <linux/pagemap.h>#include <linux/ptrace.h>#include <linux/security.h>#include <linux/signal.h>#include <linux/audit.h>#include <linux/pid_namespace.h>#include <linux/syscalls.h>#include <linux/uaccess.h>#include <linux/regset.h>#include <linux/hw_breakpoint.h>#include <linux/cn_proc.h> static int ptrace_trapping_sleep_fn(void *flags){ schedule(); return 0;} /* * ptrace a task: make the debugger its new parent and * move it to the ptrace list. * * Must be called with the tasklist lock write-held. */void __ptrace_link(struct task_struct *child, struct task_struct *new_parent){ BUG_ON(!list_empty(&child->ptrace_entry)); list_add(&child->ptrace_entry, &new_parent->ptraced); child->parent = new_parent;} /** * __ptrace_unlink - unlink ptracee and restore its execution state * @child: ptracee to be unlinked * * Remove @child from the ptrace list, move it back to the original parent, * and restore the execution state so that it conforms to the group stop * state. * * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer * exiting. For PTRACE_DETACH, unless the ptracee has been killed between * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED. * If the ptracer is exiting, the ptracee can be in any state. * * After detach, the ptracee should be in a state which conforms to the * group stop. If the group is stopped or in the process of stopping, the * ptracee should be put into TASK_STOPPED; otherwise, it should be woken * up from TASK_TRACED. * * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED, * it goes through TRACED -> RUNNING -> STOPPED transition which is similar * to but in the opposite direction of what happens while attaching to a * stopped task. However, in this direction, the intermediate RUNNING * state is not hidden even from the current ptracer and if it immediately * re-attaches and performs a WNOHANG wait(2), it may fail. * * CONTEXT: * write_lock_irq(tasklist_lock) */void __ptrace_unlink(struct task_struct *child){ BUG_ON(!child->ptrace); child->ptrace = 0; child->parent = child->real_parent; list_del_init(&child->ptrace_entry); spin_lock(&child->sighand->siglock); /* * Clear all pending traps and TRAPPING. TRAPPING should be * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly. */ task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK); task_clear_jobctl_trapping(child); /* * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and * @child isn't dead. */ if (!(child->flags & PF_EXITING) && (child->signal->flags & SIGNAL_STOP_STOPPED || child->signal->group_stop_count)) { child->jobctl |= JOBCTL_STOP_PENDING; /* * This is only possible if this thread was cloned by the * traced task running in the stopped group, set the signal * for the future reports. * FIXME: we should change ptrace_init_task() to handle this * case. */ if (!(child->jobctl & JOBCTL_STOP_SIGMASK)) child->jobctl |= SIGSTOP; } /* * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick * @child in the butt. Note that @resume should be used iff @child * is in TASK_TRACED; otherwise, we might unduly disrupt * TASK_KILLABLE sleeps. */ if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child)) signal_wake_up(child, task_is_traced(child)); spin_unlock(&child->sighand->siglock);} /** * ptrace_check_attach - check whether ptracee is ready for ptrace operation * @child: ptracee to check for * @ignore_state: don't check whether @child is currently %TASK_TRACED * * Check whether @child is being ptraced by %current and ready for further * ptrace operations. If @ignore_state is %false, @child also should be in * %TASK_TRACED state and on return the child is guaranteed to be traced * and not executing. If @ignore_state is %true, @child can be in any * state. * * CONTEXT: * Grabs and releases tasklist_lock and @child->sighand->siglock. * * RETURNS: * 0 on success, -ESRCH if %child is not ready. */int ptrace_check_attach(struct task_struct *child, bool ignore_state){ int ret = -ESRCH; /* * We take the read lock around doing both checks to close a * possible race where someone else was tracing our child and * detached between these two checks. After this locked check, * we are sure that this is our traced child and that can only * be changed by us so it's not changing right after this. */ read_lock(&tasklist_lock); if ((child->ptrace & PT_PTRACED) && child->parent == current) { /* * child->sighand can't be NULL, release_task() * does ptrace_unlink() before __exit_signal(). */ spin_lock_irq(&child->sighand->siglock); WARN_ON_ONCE(task_is_stopped(child)); if (ignore_state || (task_is_traced(child) && !(child->jobctl & JOBCTL_LISTENING))) ret = 0; spin_unlock_irq(&child->sighand->siglock); } read_unlock(&tasklist_lock); if (!ret && !ignore_state) ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH; /* All systems go.. */ return ret;} static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode){ if (mode & PTRACE_MODE_NOAUDIT) return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE); else return has_ns_capability(current, ns, CAP_SYS_PTRACE);} int __ptrace_may_access(struct task_struct *task, unsigned int mode){ const struct cred *cred = current_cred(), *tcred; /* May we inspect the given task? * This check is used both for attaching with ptrace * and for allowing access to sensitive information in /proc. * * ptrace_attach denies several cases that /proc allows * because setting up the necessary parent/child relationship * or halting the specified task is impossible. */ int dumpable = 0; /* Don't let security modules deny introspection */ if (task == current) return 0; rcu_read_lock(); tcred = __task_cred(task); if (cred->user->user_ns == tcred->user->user_ns && (cred->uid == tcred->euid && cred->uid == tcred->suid && cred->uid == tcred->uid && cred->gid == tcred->egid && cred->gid == tcred->sgid && cred->gid == tcred->gid)) goto ok; if (ptrace_has_cap(tcred->user->user_ns, mode)) goto ok; rcu_read_unlock(); return -EPERM;ok: rcu_read_unlock(); smp_rmb(); if (task->mm) dumpable = get_dumpable(task->mm); if (!dumpable && !ptrace_has_cap(task_user_ns(task), mode)) return -EPERM; return security_ptrace_access_check(task, mode);} bool ptrace_may_access(struct task_struct *task, unsigned int mode){ int err; task_lock(task); err = __ptrace_may_access(task, mode); task_unlock(task); return !err;} static int ptrace_attach(struct task_struct *task, long request, unsigned long addr, unsigned long flags){ bool seize = (request == PTRACE_SEIZE); int retval; retval = -EIO; if (seize) { if (addr != 0) goto out; if (flags & ~(unsigned long)PTRACE_O_MASK) goto out; flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT); } else { flags = PT_PTRACED; } audit_ptrace(task); retval = -EPERM; if (unlikely(task->flags & PF_KTHREAD)) goto out; if (same_thread_group(task, current)) goto out; /* * Protect exec's credential calculations against our interference; * SUID, SGID and LSM creds get determined differently * under ptrace. */ retval = -ERESTARTNOINTR; if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) goto out; task_lock(task); retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); task_unlock(task); if (retval) goto unlock_creds; write_lock_irq(&tasklist_lock); retval = -EPERM; if (unlikely(task->exit_state)) goto unlock_tasklist; if (task->ptrace) goto unlock_tasklist; if (seize) flags |= PT_SEIZED; if (ns_capable(task_user_ns(task), CAP_SYS_PTRACE)) flags |= PT_PTRACE_CAP; task->ptrace = flags; __ptrace_link(task, current); /* SEIZE doesn't trap tracee on attach */ if (!seize) send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); spin_lock(&task->sighand->siglock); /* * If the task is already STOPPED, set JOBCTL_TRAP_STOP and * TRAPPING, and kick it so that it transits to TRACED. TRAPPING * will be cleared if the child completes the transition or any * event which clears the group stop states happens. We'll wait * for the transition to complete before returning from this * function. * * This hides STOPPED -> RUNNING -> TRACED transition from the * attaching thread but a different thread in the same group can * still observe the transient RUNNING state. IOW, if another * thread's WNOHANG wait(2) on the stopped tracee races against * ATTACH, the wait(2) may fail due to the transient RUNNING. * * The following task_is_stopped() test is safe as both transitions * in and out of STOPPED are protected by siglock. */ if (task_is_stopped(task) && task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) signal_wake_up(task, 1); spin_unlock(&task->sighand->siglock); retval = 0;unlock_tasklist: write_unlock_irq(&tasklist_lock);unlock_creds: mutex_unlock(&task->signal->cred_guard_mutex);out: if (!retval) { wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, ptrace_trapping_sleep_fn, TASK_UNINTERRUPTIBLE); proc_ptrace_connector(task, PTRACE_ATTACH); } return retval;} /** * ptrace_traceme -- helper for PTRACE_TRACEME * * Performs checks and sets PT_PTRACED. * Should be used by all ptrace implementations for PTRACE_TRACEME. */static int ptrace_traceme(void){ int ret = -EPERM; write_lock_irq(&tasklist_lock); /* Are we already being traced? */ if (!current->ptrace) { ret = security_ptrace_traceme(current->parent); /* * Check PF_EXITING to ensure ->real_parent has not passed * exit_ptrace(). Otherwise we don't report the error but * pretend ->real_parent untraces us right after return. */ if (!ret && !(current->real_parent->flags & PF_EXITING)) { current->ptrace = PT_PTRACED; __ptrace_link(current, current->real_parent); } } write_unlock_irq(&tasklist_lock); return ret;} /* * Called with irqs disabled, returns true if childs should reap themselves. */static int ignoring_children(struct sighand_struct *sigh){ int ret; spin_lock(&sigh->siglock); ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); spin_unlock(&sigh->siglock); return ret;} /* * Called with tasklist_lock held for writing. * Unlink a traced task, and clean it up if it was a traced zombie. * Return true if it needs to be reaped with release_task(). * (We can't call release_task() here because we already hold tasklist_lock.) * * If it's a zombie, our attachedness prevented normal parent notification * or self-reaping. Do notification now if it would have happened earlier. * If it should reap itself, return true. * * If it's our own child, there is no notification to do. But if our normal * children self-reap, then this child was prevented by ptrace and we must * reap it now, in that case we must also wake up sub-threads sleeping in * do_wait(). */static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p){ bool dead; __ptrace_unlink(p); if (p->exit_state != EXIT_ZOMBIE) return false; dead = !thread_group_leader(p); if (!dead && thread_group_empty(p)) { if (!same_thread_group(p->real_parent, tracer)) dead = do_notify_parent(p, p->exit_signal); else if (ignoring_children(tracer->sighand)) { __wake_up_parent(p, tracer); dead = true; } } /* Mark it as in the process of being reaped. */ if (dead) p->exit_state = EXIT_DEAD; return dead;} static int ptrace_detach(struct task_struct *child, unsigned int data){ bool dead = false; if (!valid_signal(data)) return -EIO; /* Architecture-specific hardware disable .. */ ptrace_disable(child); clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); write_lock_irq(&tasklist_lock); /* * This child can be already killed. Make sure de_thread() or * our sub-thread doing do_wait() didn't do release_task() yet. */ if (child->ptrace) { child->exit_code = data; dead = __ptrace_detach(current, child); } write_unlock_irq(&tasklist_lock); proc_ptrace_connector(child, PTRACE_DETACH); if (unlikely(dead)) release_task(child); return 0;} /* * Detach all tasks we were using ptrace on. Called with tasklist held * for writing, and returns with it held too. But note it can release * and reacquire the lock. */void exit_ptrace(struct task_struct *tracer) __releases(&tasklist_lock) __acquires(&tasklist_lock){ struct task_struct *p, *n; LIST_HEAD(ptrace_dead); if (likely(list_empty(&tracer->ptraced))) return; list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { if (__ptrace_detach(tracer, p)) list_add(&p->ptrace_entry, &ptrace_dead); } write_unlock_irq(&tasklist_lock); BUG_ON(!list_empty(&tracer->ptraced)); list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) { list_del_init(&p->ptrace_entry); release_task(p); } write_lock_irq(&tasklist_lock);} int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len){ int copied = 0; while (len > 0) { char buf[128]; int this_len, retval; this_len = (len > sizeof(buf)) ? sizeof(buf) : len; retval = access_process_vm(tsk, src, buf, this_len, 0); if (!retval) { if (copied) break; return -EIO; } if (copy_to_user(dst, buf, retval)) return -EFAULT; copied += retval; src += retval; dst += retval; len -= retval; } return copied;} int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)Lines 1–500 of 1057. 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/* * linux/kernel/ptrace.c * * (C) Copyright 1999 Linus Torvalds * * Common interfaces for "ptrace()" which we do not want * to continually duplicate across every architecture. */ #include <linux/capability.h> #include <linux/export.h> #include <linux/sched.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/highmem.h> #include <linux/pagemap.h> #include <linux/ptrace.h> #include <linux/security.h> #include <linux/signal.h> #include <linux/audit.h> #include <linux/pid_namespace.h> #include <linux/syscalls.h> #include <linux/uaccess.h> #include <linux/regset.h> #include <linux/hw_breakpoint.h> #include <linux/cn_proc.h> static int ptrace_trapping_sleep_fn(void *flags) { schedule(); return 0; } /* * ptrace a task: make the debugger its new parent and * move it to the ptrace list. * * Must be called with the tasklist lock write-held. */ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) { BUG_ON(!list_empty(&child->ptrace_entry)); list_add(&child->ptrace_entry, &new_parent->ptraced); child->parent = new_parent; } /** * __ptrace_unlink - unlink ptracee and restore its execution state * @child: ptracee to be unlinked * * Remove @child from the ptrace list, move it back to the original parent, * and restore the execution state so that it conforms to the group stop * state. * * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer * exiting. For PTRACE_DETACH, unless the ptracee has been killed between * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED. * If the ptracer is exiting, the ptracee can be in any state. * * After detach, the ptracee should be in a state which conforms to the * group stop. If the group is stopped or in the process of stopping, the * ptracee should be put into TASK_STOPPED; otherwise, it should be woken * up from TASK_TRACED. * * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED, * it goes through TRACED -> RUNNING -> STOPPED transition which is similar * to but in the opposite direction of what happens while attaching to a * stopped task. However, in this direction, the intermediate RUNNING * state is not hidden even from the current ptracer and if it immediately * re-attaches and performs a WNOHANG wait(2), it may fail. * * CONTEXT: * write_lock_irq(tasklist_lock) */ void __ptrace_unlink(struct task_struct *child) { BUG_ON(!child->ptrace); child->ptrace = 0; child->parent = child->real_parent; list_del_init(&child->ptrace_entry); spin_lock(&child->sighand->siglock); /* * Clear all pending traps and TRAPPING. TRAPPING should be * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly. */ task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK); task_clear_jobctl_trapping(child); /* * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and * @child isn't dead. */ if (!(child->flags & PF_EXITING) && (child->signal->flags & SIGNAL_STOP_STOPPED || child->signal->group_stop_count)) { child->jobctl |= JOBCTL_STOP_PENDING; /* * This is only possible if this thread was cloned by the * traced task running in the stopped group, set the signal * for the future reports. * FIXME: we should change ptrace_init_task() to handle this * case. */ if (!(child->jobctl & JOBCTL_STOP_SIGMASK)) child->jobctl |= SIGSTOP; } /* * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick * @child in the butt. Note that @resume should be used iff @child * is in TASK_TRACED; otherwise, we might unduly disrupt * TASK_KILLABLE sleeps. */ if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child)) signal_wake_up(child, task_is_traced(child)); spin_unlock(&child->sighand->siglock); } /** * ptrace_check_attach - check whether ptracee is ready for ptrace operation * @child: ptracee to check for * @ignore_state: don't check whether @child is currently %TASK_TRACED * * Check whether @child is being ptraced by %current and ready for further * ptrace operations. If @ignore_state is %false, @child also should be in * %TASK_TRACED state and on return the child is guaranteed to be traced * and not executing. If @ignore_state is %true, @child can be in any * state. * * CONTEXT: * Grabs and releases tasklist_lock and @child->sighand->siglock. * * RETURNS: * 0 on success, -ESRCH if %child is not ready. */ int ptrace_check_attach(struct task_struct *child, bool ignore_state) { int ret = -ESRCH; /* * We take the read lock around doing both checks to close a * possible race where someone else was tracing our child and * detached between these two checks. After this locked check, * we are sure that this is our traced child and that can only * be changed by us so it's not changing right after this. */ read_lock(&tasklist_lock); if ((child->ptrace & PT_PTRACED) && child->parent == current) { /* * child->sighand can't be NULL, release_task() * does ptrace_unlink() before __exit_signal(). */ spin_lock_irq(&child->sighand->siglock); WARN_ON_ONCE(task_is_stopped(child)); if (ignore_state || (task_is_traced(child) && !(child->jobctl & JOBCTL_LISTENING))) ret = 0; spin_unlock_irq(&child->sighand->siglock); } read_unlock(&tasklist_lock); if (!ret && !ignore_state) ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH; /* All systems go.. */ return ret; } static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode) { if (mode & PTRACE_MODE_NOAUDIT) return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE); else return has_ns_capability(current, ns, CAP_SYS_PTRACE); } int __ptrace_may_access(struct task_struct *task, unsigned int mode) { const struct cred *cred = current_cred(), *tcred; /* May we inspect the given task? * This check is used both for attaching with ptrace * and for allowing access to sensitive information in /proc. * * ptrace_attach denies several cases that /proc allows * because setting up the necessary parent/child relationship * or halting the specified task is impossible. */ int dumpable = 0; /* Don't let security modules deny introspection */ if (task == current) return 0; rcu_read_lock(); tcred = __task_cred(task); if (cred->user->user_ns == tcred->user->user_ns && (cred->uid == tcred->euid && cred->uid == tcred->suid && cred->uid == tcred->uid && cred->gid == tcred->egid && cred->gid == tcred->sgid && cred->gid == tcred->gid)) goto ok; if (ptrace_has_cap(tcred->user->user_ns, mode)) goto ok; rcu_read_unlock(); return -EPERM; ok: rcu_read_unlock(); smp_rmb(); if (task->mm) dumpable = get_dumpable(task->mm); if (!dumpable && !ptrace_has_cap(task_user_ns(task), mode)) return -EPERM; return security_ptrace_access_check(task, mode); } bool ptrace_may_access(struct task_struct *task, unsigned int mode) { int err; task_lock(task); err = __ptrace_may_access(task, mode); task_unlock(task); return !err; } static int ptrace_attach(struct task_struct *task, long request, unsigned long addr, unsigned long flags) { bool seize = (request == PTRACE_SEIZE); int retval; retval = -EIO; if (seize) { if (addr != 0) goto out; if (flags & ~(unsigned long)PTRACE_O_MASK) goto out; flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT); } else { flags = PT_PTRACED; } audit_ptrace(task); retval = -EPERM; if (unlikely(task->flags & PF_KTHREAD)) goto out; if (same_thread_group(task, current)) goto out; /* * Protect exec's credential calculations against our interference; * SUID, SGID and LSM creds get determined differently * under ptrace. */ retval = -ERESTARTNOINTR; if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) goto out; task_lock(task); retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); task_unlock(task); if (retval) goto unlock_creds; write_lock_irq(&tasklist_lock); retval = -EPERM; if (unlikely(task->exit_state)) goto unlock_tasklist; if (task->ptrace) goto unlock_tasklist; if (seize) flags |= PT_SEIZED; if (ns_capable(task_user_ns(task), CAP_SYS_PTRACE)) flags |= PT_PTRACE_CAP; task->ptrace = flags; __ptrace_link(task, current); /* SEIZE doesn't trap tracee on attach */ if (!seize) send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); spin_lock(&task->sighand->siglock); /* * If the task is already STOPPED, set JOBCTL_TRAP_STOP and * TRAPPING, and kick it so that it transits to TRACED. TRAPPING * will be cleared if the child completes the transition or any * event which clears the group stop states happens. We'll wait * for the transition to complete before returning from this * function. * * This hides STOPPED -> RUNNING -> TRACED transition from the * attaching thread but a different thread in the same group can * still observe the transient RUNNING state. IOW, if another * thread's WNOHANG wait(2) on the stopped tracee races against * ATTACH, the wait(2) may fail due to the transient RUNNING. * * The following task_is_stopped() test is safe as both transitions * in and out of STOPPED are protected by siglock. */ if (task_is_stopped(task) && task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) signal_wake_up(task, 1); spin_unlock(&task->sighand->siglock); retval = 0; unlock_tasklist: write_unlock_irq(&tasklist_lock); unlock_creds: mutex_unlock(&task->signal->cred_guard_mutex); out: if (!retval) { wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, ptrace_trapping_sleep_fn, TASK_UNINTERRUPTIBLE); proc_ptrace_connector(task, PTRACE_ATTACH); } return retval; } /** * ptrace_traceme -- helper for PTRACE_TRACEME * * Performs checks and sets PT_PTRACED. * Should be used by all ptrace implementations for PTRACE_TRACEME. */ static int ptrace_traceme(void) { int ret = -EPERM; write_lock_irq(&tasklist_lock); /* Are we already being traced? */ if (!current->ptrace) { ret = security_ptrace_traceme(current->parent); /* * Check PF_EXITING to ensure ->real_parent has not passed * exit_ptrace(). Otherwise we don't report the error but * pretend ->real_parent untraces us right after return. */ if (!ret && !(current->real_parent->flags & PF_EXITING)) { current->ptrace = PT_PTRACED; __ptrace_link(current, current->real_parent); } } write_unlock_irq(&tasklist_lock); return ret; } /* * Called with irqs disabled, returns true if childs should reap themselves. */ static int ignoring_children(struct sighand_struct *sigh) { int ret; spin_lock(&sigh->siglock); ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); spin_unlock(&sigh->siglock); return ret; } /* * Called with tasklist_lock held for writing. * Unlink a traced task, and clean it up if it was a traced zombie. * Return true if it needs to be reaped with release_task(). * (We can't call release_task() here because we already hold tasklist_lock.) * * If it's a zombie, our attachedness prevented normal parent notification * or self-reaping. Do notification now if it would have happened earlier. * If it should reap itself, return true. * * If it's our own child, there is no notification to do. But if our normal * children self-reap, then this child was prevented by ptrace and we must * reap it now, in that case we must also wake up sub-threads sleeping in * do_wait(). */ static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) { bool dead; __ptrace_unlink(p); if (p->exit_state != EXIT_ZOMBIE) return false; dead = !thread_group_leader(p); if (!dead && thread_group_empty(p)) { if (!same_thread_group(p->real_parent, tracer)) dead = do_notify_parent(p, p->exit_signal); else if (ignoring_children(tracer->sighand)) { __wake_up_parent(p, tracer); dead = true; } } /* Mark it as in the process of being reaped. */ if (dead) p->exit_state = EXIT_DEAD; return dead; } static int ptrace_detach(struct task_struct *child, unsigned int data) { bool dead = false; if (!valid_signal(data)) return -EIO; /* Architecture-specific hardware disable .. */ ptrace_disable(child); clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); write_lock_irq(&tasklist_lock); /* * This child can be already killed. Make sure de_thread() or * our sub-thread doing do_wait() didn't do release_task() yet. */ if (child->ptrace) { child->exit_code = data; dead = __ptrace_detach(current, child); } write_unlock_irq(&tasklist_lock); proc_ptrace_connector(child, PTRACE_DETACH); if (unlikely(dead)) release_task(child); return 0; } /* * Detach all tasks we were using ptrace on. Called with tasklist held * for writing, and returns with it held too. But note it can release * and reacquire the lock. */ void exit_ptrace(struct task_struct *tracer) __releases(&tasklist_lock) __acquires(&tasklist_lock) { struct task_struct *p, *n; LIST_HEAD(ptrace_dead); if (likely(list_empty(&tracer->ptraced))) return; list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { if (__ptrace_detach(tracer, p)) list_add(&p->ptrace_entry, &ptrace_dead); } write_unlock_irq(&tasklist_lock); BUG_ON(!list_empty(&tracer->ptraced)); list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) { list_del_init(&p->ptrace_entry); release_task(p); } write_lock_irq(&tasklist_lock); } int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) { int copied = 0; while (len > 0) { char buf[128]; int this_len, retval; this_len = (len > sizeof(buf)) ? sizeof(buf) : len; retval = access_process_vm(tsk, src, buf, this_len, 0); if (!retval) { if (copied) break; return -EIO; } if (copy_to_user(dst, buf, retval)) return -EFAULT; copied += retval; src += retval; dst += retval; len -= retval; } return copied; } int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)