11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/kernel/ptrace.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * (C) Copyright 1999 Linus Torvalds 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Common interfaces for "ptrace()" which we do not want 71da177e4SLinus Torvalds * to continually duplicate across every architecture. 81da177e4SLinus Torvalds */ 91da177e4SLinus Torvalds 10c59ede7bSRandy.Dunlap #include <linux/capability.h> 111da177e4SLinus Torvalds #include <linux/module.h> 121da177e4SLinus Torvalds #include <linux/sched.h> 131da177e4SLinus Torvalds #include <linux/errno.h> 141da177e4SLinus Torvalds #include <linux/mm.h> 151da177e4SLinus Torvalds #include <linux/highmem.h> 161da177e4SLinus Torvalds #include <linux/pagemap.h> 171da177e4SLinus Torvalds #include <linux/smp_lock.h> 181da177e4SLinus Torvalds #include <linux/ptrace.h> 191da177e4SLinus Torvalds #include <linux/security.h> 207ed20e1aSJesper Juhl #include <linux/signal.h> 21a5cb013dSAl Viro #include <linux/audit.h> 22b488893aSPavel Emelyanov #include <linux/pid_namespace.h> 23f17d30a8SAdrian Bunk #include <linux/syscalls.h> 243a709703SRoland McGrath #include <linux/uaccess.h> 251da177e4SLinus Torvalds 26bf53de90SMarkus Metzger 27bf53de90SMarkus Metzger /* 281da177e4SLinus Torvalds * ptrace a task: make the debugger its new parent and 291da177e4SLinus Torvalds * move it to the ptrace list. 301da177e4SLinus Torvalds * 311da177e4SLinus Torvalds * Must be called with the tasklist lock write-held. 321da177e4SLinus Torvalds */ 3336c8b586SIngo Molnar void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) 341da177e4SLinus Torvalds { 35f470021aSRoland McGrath BUG_ON(!list_empty(&child->ptrace_entry)); 36f470021aSRoland McGrath list_add(&child->ptrace_entry, &new_parent->ptraced); 371da177e4SLinus Torvalds child->parent = new_parent; 381da177e4SLinus Torvalds } 391da177e4SLinus Torvalds 401da177e4SLinus Torvalds /* 411da177e4SLinus Torvalds * Turn a tracing stop into a normal stop now, since with no tracer there 421da177e4SLinus Torvalds * would be no way to wake it up with SIGCONT or SIGKILL. If there was a 431da177e4SLinus Torvalds * signal sent that would resume the child, but didn't because it was in 441da177e4SLinus Torvalds * TASK_TRACED, resume it now. 451da177e4SLinus Torvalds * Requires that irqs be disabled. 461da177e4SLinus Torvalds */ 47b747c8c1SAdrian Bunk static void ptrace_untrace(struct task_struct *child) 481da177e4SLinus Torvalds { 491da177e4SLinus Torvalds spin_lock(&child->sighand->siglock); 506618a3e2SMatthew Wilcox if (task_is_traced(child)) { 511ee11844SOleg Nesterov /* 521ee11844SOleg Nesterov * If the group stop is completed or in progress, 531ee11844SOleg Nesterov * this thread was already counted as stopped. 541ee11844SOleg Nesterov */ 551ee11844SOleg Nesterov if (child->signal->flags & SIGNAL_STOP_STOPPED || 561ee11844SOleg Nesterov child->signal->group_stop_count) 57d9ae90acSOleg Nesterov __set_task_state(child, TASK_STOPPED); 581ee11844SOleg Nesterov else 591da177e4SLinus Torvalds signal_wake_up(child, 1); 601da177e4SLinus Torvalds } 611da177e4SLinus Torvalds spin_unlock(&child->sighand->siglock); 621da177e4SLinus Torvalds } 631da177e4SLinus Torvalds 641da177e4SLinus Torvalds /* 651da177e4SLinus Torvalds * unptrace a task: move it back to its original parent and 661da177e4SLinus Torvalds * remove it from the ptrace list. 671da177e4SLinus Torvalds * 681da177e4SLinus Torvalds * Must be called with the tasklist lock write-held. 691da177e4SLinus Torvalds */ 7036c8b586SIngo Molnar void __ptrace_unlink(struct task_struct *child) 711da177e4SLinus Torvalds { 725ecfbae0SOleg Nesterov BUG_ON(!child->ptrace); 735ecfbae0SOleg Nesterov 741da177e4SLinus Torvalds child->ptrace = 0; 751da177e4SLinus Torvalds child->parent = child->real_parent; 76f470021aSRoland McGrath list_del_init(&child->ptrace_entry); 771da177e4SLinus Torvalds 78bf53de90SMarkus Metzger arch_ptrace_untrace(child); 796618a3e2SMatthew Wilcox if (task_is_traced(child)) 801da177e4SLinus Torvalds ptrace_untrace(child); 811da177e4SLinus Torvalds } 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds /* 841da177e4SLinus Torvalds * Check that we have indeed attached to the thing.. 851da177e4SLinus Torvalds */ 861da177e4SLinus Torvalds int ptrace_check_attach(struct task_struct *child, int kill) 871da177e4SLinus Torvalds { 881da177e4SLinus Torvalds int ret = -ESRCH; 891da177e4SLinus Torvalds 901da177e4SLinus Torvalds /* 911da177e4SLinus Torvalds * We take the read lock around doing both checks to close a 921da177e4SLinus Torvalds * possible race where someone else was tracing our child and 931da177e4SLinus Torvalds * detached between these two checks. After this locked check, 941da177e4SLinus Torvalds * we are sure that this is our traced child and that can only 951da177e4SLinus Torvalds * be changed by us so it's not changing right after this. 961da177e4SLinus Torvalds */ 971da177e4SLinus Torvalds read_lock(&tasklist_lock); 98c0c0b649SOleg Nesterov if ((child->ptrace & PT_PTRACED) && child->parent == current) { 991da177e4SLinus Torvalds ret = 0; 100c0c0b649SOleg Nesterov /* 101c0c0b649SOleg Nesterov * child->sighand can't be NULL, release_task() 102c0c0b649SOleg Nesterov * does ptrace_unlink() before __exit_signal(). 103c0c0b649SOleg Nesterov */ 1041da177e4SLinus Torvalds spin_lock_irq(&child->sighand->siglock); 105d9ae90acSOleg Nesterov if (task_is_stopped(child)) 1061da177e4SLinus Torvalds child->state = TASK_TRACED; 107d9ae90acSOleg Nesterov else if (!task_is_traced(child) && !kill) 1081da177e4SLinus Torvalds ret = -ESRCH; 1091da177e4SLinus Torvalds spin_unlock_irq(&child->sighand->siglock); 1101da177e4SLinus Torvalds } 1111da177e4SLinus Torvalds read_unlock(&tasklist_lock); 1121da177e4SLinus Torvalds 113d9ae90acSOleg Nesterov if (!ret && !kill) 11485ba2d86SRoland McGrath ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH; 1151da177e4SLinus Torvalds 1161da177e4SLinus Torvalds /* All systems go.. */ 1171da177e4SLinus Torvalds return ret; 1181da177e4SLinus Torvalds } 1191da177e4SLinus Torvalds 120006ebb40SStephen Smalley int __ptrace_may_access(struct task_struct *task, unsigned int mode) 121ab8d11beSMiklos Szeredi { 122c69e8d9cSDavid Howells const struct cred *cred = current_cred(), *tcred; 123b6dff3ecSDavid Howells 124df26c40eSEric W. Biederman /* May we inspect the given task? 125df26c40eSEric W. Biederman * This check is used both for attaching with ptrace 126df26c40eSEric W. Biederman * and for allowing access to sensitive information in /proc. 127df26c40eSEric W. Biederman * 128df26c40eSEric W. Biederman * ptrace_attach denies several cases that /proc allows 129df26c40eSEric W. Biederman * because setting up the necessary parent/child relationship 130df26c40eSEric W. Biederman * or halting the specified task is impossible. 131df26c40eSEric W. Biederman */ 132df26c40eSEric W. Biederman int dumpable = 0; 133df26c40eSEric W. Biederman /* Don't let security modules deny introspection */ 134df26c40eSEric W. Biederman if (task == current) 135df26c40eSEric W. Biederman return 0; 136c69e8d9cSDavid Howells rcu_read_lock(); 137c69e8d9cSDavid Howells tcred = __task_cred(task); 138c69e8d9cSDavid Howells if ((cred->uid != tcred->euid || 139c69e8d9cSDavid Howells cred->uid != tcred->suid || 140c69e8d9cSDavid Howells cred->uid != tcred->uid || 141c69e8d9cSDavid Howells cred->gid != tcred->egid || 142c69e8d9cSDavid Howells cred->gid != tcred->sgid || 143c69e8d9cSDavid Howells cred->gid != tcred->gid) && 144c69e8d9cSDavid Howells !capable(CAP_SYS_PTRACE)) { 145c69e8d9cSDavid Howells rcu_read_unlock(); 146ab8d11beSMiklos Szeredi return -EPERM; 147c69e8d9cSDavid Howells } 148c69e8d9cSDavid Howells rcu_read_unlock(); 149ab8d11beSMiklos Szeredi smp_rmb(); 150df26c40eSEric W. Biederman if (task->mm) 1516c5d5238SKawai, Hidehiro dumpable = get_dumpable(task->mm); 152df26c40eSEric W. Biederman if (!dumpable && !capable(CAP_SYS_PTRACE)) 153ab8d11beSMiklos Szeredi return -EPERM; 154ab8d11beSMiklos Szeredi 1555cd9c58fSDavid Howells return security_ptrace_may_access(task, mode); 156ab8d11beSMiklos Szeredi } 157ab8d11beSMiklos Szeredi 158006ebb40SStephen Smalley bool ptrace_may_access(struct task_struct *task, unsigned int mode) 159ab8d11beSMiklos Szeredi { 160ab8d11beSMiklos Szeredi int err; 161ab8d11beSMiklos Szeredi task_lock(task); 162006ebb40SStephen Smalley err = __ptrace_may_access(task, mode); 163ab8d11beSMiklos Szeredi task_unlock(task); 1643a709703SRoland McGrath return !err; 165ab8d11beSMiklos Szeredi } 166ab8d11beSMiklos Szeredi 1671da177e4SLinus Torvalds int ptrace_attach(struct task_struct *task) 1681da177e4SLinus Torvalds { 1691da177e4SLinus Torvalds int retval; 1706175ecfeSSripathi Kodi unsigned long flags; 171f5b40e36SLinus Torvalds 172a5cb013dSAl Viro audit_ptrace(task); 173a5cb013dSAl Viro 1741da177e4SLinus Torvalds retval = -EPERM; 175b79b7ba9SOleg Nesterov if (unlikely(task->flags & PF_KTHREAD)) 176b79b7ba9SOleg Nesterov goto out; 177bac0abd6SPavel Emelyanov if (same_thread_group(task, current)) 178f5b40e36SLinus Torvalds goto out; 179f5b40e36SLinus Torvalds 180f2f0b00aSOleg Nesterov /* 181f2f0b00aSOleg Nesterov * Protect exec's credential calculations against our interference; 1825e751e99SDavid Howells * interference; SUID, SGID and LSM creds get determined differently 1835e751e99SDavid Howells * under ptrace. 184d84f4f99SDavid Howells */ 1855e751e99SDavid Howells retval = mutex_lock_interruptible(&task->cred_guard_mutex); 186d84f4f99SDavid Howells if (retval < 0) 187d84f4f99SDavid Howells goto out; 188f358166aSLinus Torvalds repeat: 189f358166aSLinus Torvalds /* 190f358166aSLinus Torvalds * Nasty, nasty. 191f358166aSLinus Torvalds * 192f358166aSLinus Torvalds * We want to hold both the task-lock and the 193f358166aSLinus Torvalds * tasklist_lock for writing at the same time. 194f358166aSLinus Torvalds * But that's against the rules (tasklist_lock 195f358166aSLinus Torvalds * is taken for reading by interrupts on other 196f358166aSLinus Torvalds * cpu's that may have task_lock). 197f358166aSLinus Torvalds */ 198f5b40e36SLinus Torvalds task_lock(task); 1996175ecfeSSripathi Kodi if (!write_trylock_irqsave(&tasklist_lock, flags)) { 200f358166aSLinus Torvalds task_unlock(task); 201f358166aSLinus Torvalds do { 202f358166aSLinus Torvalds cpu_relax(); 203f358166aSLinus Torvalds } while (!write_can_lock(&tasklist_lock)); 204f358166aSLinus Torvalds goto repeat; 205f358166aSLinus Torvalds } 206f5b40e36SLinus Torvalds 207006ebb40SStephen Smalley retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); 2081da177e4SLinus Torvalds if (retval) 2091da177e4SLinus Torvalds goto bad; 2101da177e4SLinus Torvalds 211b79b7ba9SOleg Nesterov retval = -EPERM; 212b79b7ba9SOleg Nesterov if (unlikely(task->exit_state)) 213b79b7ba9SOleg Nesterov goto bad; 214f2f0b00aSOleg Nesterov if (task->ptrace) 215b79b7ba9SOleg Nesterov goto bad; 216b79b7ba9SOleg Nesterov 217f2f0b00aSOleg Nesterov task->ptrace = PT_PTRACED; 2181da177e4SLinus Torvalds if (capable(CAP_SYS_PTRACE)) 2191da177e4SLinus Torvalds task->ptrace |= PT_PTRACE_CAP; 2201da177e4SLinus Torvalds 2211da177e4SLinus Torvalds __ptrace_link(task, current); 22233e9fc7dSOleg Nesterov send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); 223b79b7ba9SOleg Nesterov 224b79b7ba9SOleg Nesterov retval = 0; 2251da177e4SLinus Torvalds bad: 2266175ecfeSSripathi Kodi write_unlock_irqrestore(&tasklist_lock, flags); 2271da177e4SLinus Torvalds task_unlock(task); 2285e751e99SDavid Howells mutex_unlock(&task->cred_guard_mutex); 229f5b40e36SLinus Torvalds out: 2301da177e4SLinus Torvalds return retval; 2311da177e4SLinus Torvalds } 2321da177e4SLinus Torvalds 233f2f0b00aSOleg Nesterov /** 234f2f0b00aSOleg Nesterov * ptrace_traceme -- helper for PTRACE_TRACEME 235f2f0b00aSOleg Nesterov * 236f2f0b00aSOleg Nesterov * Performs checks and sets PT_PTRACED. 237f2f0b00aSOleg Nesterov * Should be used by all ptrace implementations for PTRACE_TRACEME. 238f2f0b00aSOleg Nesterov */ 239f2f0b00aSOleg Nesterov int ptrace_traceme(void) 240f2f0b00aSOleg Nesterov { 241f2f0b00aSOleg Nesterov int ret = -EPERM; 242f2f0b00aSOleg Nesterov 243f2f0b00aSOleg Nesterov /* 244f2f0b00aSOleg Nesterov * Are we already being traced? 245f2f0b00aSOleg Nesterov */ 246f2f0b00aSOleg Nesterov repeat: 247f2f0b00aSOleg Nesterov task_lock(current); 248f2f0b00aSOleg Nesterov if (!current->ptrace) { 249f2f0b00aSOleg Nesterov /* 250f2f0b00aSOleg Nesterov * See ptrace_attach() comments about the locking here. 251f2f0b00aSOleg Nesterov */ 252f2f0b00aSOleg Nesterov unsigned long flags; 253f2f0b00aSOleg Nesterov if (!write_trylock_irqsave(&tasklist_lock, flags)) { 254f2f0b00aSOleg Nesterov task_unlock(current); 255f2f0b00aSOleg Nesterov do { 256f2f0b00aSOleg Nesterov cpu_relax(); 257f2f0b00aSOleg Nesterov } while (!write_can_lock(&tasklist_lock)); 258f2f0b00aSOleg Nesterov goto repeat; 259f2f0b00aSOleg Nesterov } 260f2f0b00aSOleg Nesterov 261f2f0b00aSOleg Nesterov ret = security_ptrace_traceme(current->parent); 262f2f0b00aSOleg Nesterov 263f2f0b00aSOleg Nesterov /* 264f2f0b00aSOleg Nesterov * Check PF_EXITING to ensure ->real_parent has not passed 265f2f0b00aSOleg Nesterov * exit_ptrace(). Otherwise we don't report the error but 266f2f0b00aSOleg Nesterov * pretend ->real_parent untraces us right after return. 267f2f0b00aSOleg Nesterov */ 268f2f0b00aSOleg Nesterov if (!ret && !(current->real_parent->flags & PF_EXITING)) { 269f2f0b00aSOleg Nesterov current->ptrace = PT_PTRACED; 270f2f0b00aSOleg Nesterov __ptrace_link(current, current->real_parent); 271f2f0b00aSOleg Nesterov } 272f2f0b00aSOleg Nesterov 273f2f0b00aSOleg Nesterov write_unlock_irqrestore(&tasklist_lock, flags); 274f2f0b00aSOleg Nesterov } 275f2f0b00aSOleg Nesterov task_unlock(current); 276f2f0b00aSOleg Nesterov return ret; 277f2f0b00aSOleg Nesterov } 278f2f0b00aSOleg Nesterov 27939c626aeSOleg Nesterov /* 28039c626aeSOleg Nesterov * Called with irqs disabled, returns true if childs should reap themselves. 28139c626aeSOleg Nesterov */ 28239c626aeSOleg Nesterov static int ignoring_children(struct sighand_struct *sigh) 28339c626aeSOleg Nesterov { 28439c626aeSOleg Nesterov int ret; 28539c626aeSOleg Nesterov spin_lock(&sigh->siglock); 28639c626aeSOleg Nesterov ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || 28739c626aeSOleg Nesterov (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); 28839c626aeSOleg Nesterov spin_unlock(&sigh->siglock); 28939c626aeSOleg Nesterov return ret; 29039c626aeSOleg Nesterov } 29139c626aeSOleg Nesterov 29239c626aeSOleg Nesterov /* 29339c626aeSOleg Nesterov * Called with tasklist_lock held for writing. 29439c626aeSOleg Nesterov * Unlink a traced task, and clean it up if it was a traced zombie. 29539c626aeSOleg Nesterov * Return true if it needs to be reaped with release_task(). 29639c626aeSOleg Nesterov * (We can't call release_task() here because we already hold tasklist_lock.) 29739c626aeSOleg Nesterov * 29839c626aeSOleg Nesterov * If it's a zombie, our attachedness prevented normal parent notification 29939c626aeSOleg Nesterov * or self-reaping. Do notification now if it would have happened earlier. 30039c626aeSOleg Nesterov * If it should reap itself, return true. 30139c626aeSOleg Nesterov * 30239c626aeSOleg Nesterov * If it's our own child, there is no notification to do. 30339c626aeSOleg Nesterov * But if our normal children self-reap, then this child 30439c626aeSOleg Nesterov * was prevented by ptrace and we must reap it now. 30539c626aeSOleg Nesterov */ 30639c626aeSOleg Nesterov static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) 30739c626aeSOleg Nesterov { 30839c626aeSOleg Nesterov __ptrace_unlink(p); 30939c626aeSOleg Nesterov 31039c626aeSOleg Nesterov if (p->exit_state == EXIT_ZOMBIE) { 31139c626aeSOleg Nesterov if (!task_detached(p) && thread_group_empty(p)) { 31239c626aeSOleg Nesterov if (!same_thread_group(p->real_parent, tracer)) 31339c626aeSOleg Nesterov do_notify_parent(p, p->exit_signal); 31439c626aeSOleg Nesterov else if (ignoring_children(tracer->sighand)) 31539c626aeSOleg Nesterov p->exit_signal = -1; 31639c626aeSOleg Nesterov } 31739c626aeSOleg Nesterov if (task_detached(p)) { 31839c626aeSOleg Nesterov /* Mark it as in the process of being reaped. */ 31939c626aeSOleg Nesterov p->exit_state = EXIT_DEAD; 32039c626aeSOleg Nesterov return true; 32139c626aeSOleg Nesterov } 32239c626aeSOleg Nesterov } 32339c626aeSOleg Nesterov 32439c626aeSOleg Nesterov return false; 32539c626aeSOleg Nesterov } 32639c626aeSOleg Nesterov 3271da177e4SLinus Torvalds int ptrace_detach(struct task_struct *child, unsigned int data) 3281da177e4SLinus Torvalds { 32939c626aeSOleg Nesterov bool dead = false; 3304576145cSOleg Nesterov 3317ed20e1aSJesper Juhl if (!valid_signal(data)) 3321da177e4SLinus Torvalds return -EIO; 3331da177e4SLinus Torvalds 3341da177e4SLinus Torvalds /* Architecture-specific hardware disable .. */ 3351da177e4SLinus Torvalds ptrace_disable(child); 3367d941432SRoland McGrath clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 3371da177e4SLinus Torvalds 33895c3eb76SOleg Nesterov write_lock_irq(&tasklist_lock); 33939c626aeSOleg Nesterov /* 34039c626aeSOleg Nesterov * This child can be already killed. Make sure de_thread() or 34139c626aeSOleg Nesterov * our sub-thread doing do_wait() didn't do release_task() yet. 34239c626aeSOleg Nesterov */ 34395c3eb76SOleg Nesterov if (child->ptrace) { 34495c3eb76SOleg Nesterov child->exit_code = data; 3454576145cSOleg Nesterov dead = __ptrace_detach(current, child); 346edaba2c5SOleg Nesterov if (!child->exit_state) 347edaba2c5SOleg Nesterov wake_up_process(child); 34895c3eb76SOleg Nesterov } 3491da177e4SLinus Torvalds write_unlock_irq(&tasklist_lock); 3501da177e4SLinus Torvalds 3514576145cSOleg Nesterov if (unlikely(dead)) 3524576145cSOleg Nesterov release_task(child); 3534576145cSOleg Nesterov 3541da177e4SLinus Torvalds return 0; 3551da177e4SLinus Torvalds } 3561da177e4SLinus Torvalds 35739c626aeSOleg Nesterov /* 35839c626aeSOleg Nesterov * Detach all tasks we were using ptrace on. 35939c626aeSOleg Nesterov */ 36039c626aeSOleg Nesterov void exit_ptrace(struct task_struct *tracer) 36139c626aeSOleg Nesterov { 36239c626aeSOleg Nesterov struct task_struct *p, *n; 36339c626aeSOleg Nesterov LIST_HEAD(ptrace_dead); 36439c626aeSOleg Nesterov 36539c626aeSOleg Nesterov write_lock_irq(&tasklist_lock); 36639c626aeSOleg Nesterov list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { 36739c626aeSOleg Nesterov if (__ptrace_detach(tracer, p)) 36839c626aeSOleg Nesterov list_add(&p->ptrace_entry, &ptrace_dead); 36939c626aeSOleg Nesterov } 37039c626aeSOleg Nesterov write_unlock_irq(&tasklist_lock); 37139c626aeSOleg Nesterov 37239c626aeSOleg Nesterov BUG_ON(!list_empty(&tracer->ptraced)); 37339c626aeSOleg Nesterov 37439c626aeSOleg Nesterov list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) { 37539c626aeSOleg Nesterov list_del_init(&p->ptrace_entry); 37639c626aeSOleg Nesterov release_task(p); 37739c626aeSOleg Nesterov } 37839c626aeSOleg Nesterov } 37939c626aeSOleg Nesterov 3801da177e4SLinus Torvalds int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) 3811da177e4SLinus Torvalds { 3821da177e4SLinus Torvalds int copied = 0; 3831da177e4SLinus Torvalds 3841da177e4SLinus Torvalds while (len > 0) { 3851da177e4SLinus Torvalds char buf[128]; 3861da177e4SLinus Torvalds int this_len, retval; 3871da177e4SLinus Torvalds 3881da177e4SLinus Torvalds this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 3891da177e4SLinus Torvalds retval = access_process_vm(tsk, src, buf, this_len, 0); 3901da177e4SLinus Torvalds if (!retval) { 3911da177e4SLinus Torvalds if (copied) 3921da177e4SLinus Torvalds break; 3931da177e4SLinus Torvalds return -EIO; 3941da177e4SLinus Torvalds } 3951da177e4SLinus Torvalds if (copy_to_user(dst, buf, retval)) 3961da177e4SLinus Torvalds return -EFAULT; 3971da177e4SLinus Torvalds copied += retval; 3981da177e4SLinus Torvalds src += retval; 3991da177e4SLinus Torvalds dst += retval; 4001da177e4SLinus Torvalds len -= retval; 4011da177e4SLinus Torvalds } 4021da177e4SLinus Torvalds return copied; 4031da177e4SLinus Torvalds } 4041da177e4SLinus Torvalds 4051da177e4SLinus Torvalds int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) 4061da177e4SLinus Torvalds { 4071da177e4SLinus Torvalds int copied = 0; 4081da177e4SLinus Torvalds 4091da177e4SLinus Torvalds while (len > 0) { 4101da177e4SLinus Torvalds char buf[128]; 4111da177e4SLinus Torvalds int this_len, retval; 4121da177e4SLinus Torvalds 4131da177e4SLinus Torvalds this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 4141da177e4SLinus Torvalds if (copy_from_user(buf, src, this_len)) 4151da177e4SLinus Torvalds return -EFAULT; 4161da177e4SLinus Torvalds retval = access_process_vm(tsk, dst, buf, this_len, 1); 4171da177e4SLinus Torvalds if (!retval) { 4181da177e4SLinus Torvalds if (copied) 4191da177e4SLinus Torvalds break; 4201da177e4SLinus Torvalds return -EIO; 4211da177e4SLinus Torvalds } 4221da177e4SLinus Torvalds copied += retval; 4231da177e4SLinus Torvalds src += retval; 4241da177e4SLinus Torvalds dst += retval; 4251da177e4SLinus Torvalds len -= retval; 4261da177e4SLinus Torvalds } 4271da177e4SLinus Torvalds return copied; 4281da177e4SLinus Torvalds } 4291da177e4SLinus Torvalds 4301da177e4SLinus Torvalds static int ptrace_setoptions(struct task_struct *child, long data) 4311da177e4SLinus Torvalds { 4321da177e4SLinus Torvalds child->ptrace &= ~PT_TRACE_MASK; 4331da177e4SLinus Torvalds 4341da177e4SLinus Torvalds if (data & PTRACE_O_TRACESYSGOOD) 4351da177e4SLinus Torvalds child->ptrace |= PT_TRACESYSGOOD; 4361da177e4SLinus Torvalds 4371da177e4SLinus Torvalds if (data & PTRACE_O_TRACEFORK) 4381da177e4SLinus Torvalds child->ptrace |= PT_TRACE_FORK; 4391da177e4SLinus Torvalds 4401da177e4SLinus Torvalds if (data & PTRACE_O_TRACEVFORK) 4411da177e4SLinus Torvalds child->ptrace |= PT_TRACE_VFORK; 4421da177e4SLinus Torvalds 4431da177e4SLinus Torvalds if (data & PTRACE_O_TRACECLONE) 4441da177e4SLinus Torvalds child->ptrace |= PT_TRACE_CLONE; 4451da177e4SLinus Torvalds 4461da177e4SLinus Torvalds if (data & PTRACE_O_TRACEEXEC) 4471da177e4SLinus Torvalds child->ptrace |= PT_TRACE_EXEC; 4481da177e4SLinus Torvalds 4491da177e4SLinus Torvalds if (data & PTRACE_O_TRACEVFORKDONE) 4501da177e4SLinus Torvalds child->ptrace |= PT_TRACE_VFORK_DONE; 4511da177e4SLinus Torvalds 4521da177e4SLinus Torvalds if (data & PTRACE_O_TRACEEXIT) 4531da177e4SLinus Torvalds child->ptrace |= PT_TRACE_EXIT; 4541da177e4SLinus Torvalds 4551da177e4SLinus Torvalds return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; 4561da177e4SLinus Torvalds } 4571da177e4SLinus Torvalds 458e16b2781SRoland McGrath static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info) 4591da177e4SLinus Torvalds { 4601da177e4SLinus Torvalds int error = -ESRCH; 4611da177e4SLinus Torvalds 4621da177e4SLinus Torvalds read_lock(&tasklist_lock); 4631da177e4SLinus Torvalds if (likely(child->sighand != NULL)) { 4641da177e4SLinus Torvalds error = -EINVAL; 4651da177e4SLinus Torvalds spin_lock_irq(&child->sighand->siglock); 4661da177e4SLinus Torvalds if (likely(child->last_siginfo != NULL)) { 467e16b2781SRoland McGrath *info = *child->last_siginfo; 4681da177e4SLinus Torvalds error = 0; 4691da177e4SLinus Torvalds } 4701da177e4SLinus Torvalds spin_unlock_irq(&child->sighand->siglock); 4711da177e4SLinus Torvalds } 4721da177e4SLinus Torvalds read_unlock(&tasklist_lock); 4731da177e4SLinus Torvalds return error; 4741da177e4SLinus Torvalds } 4751da177e4SLinus Torvalds 476e16b2781SRoland McGrath static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info) 4771da177e4SLinus Torvalds { 4781da177e4SLinus Torvalds int error = -ESRCH; 4791da177e4SLinus Torvalds 4801da177e4SLinus Torvalds read_lock(&tasklist_lock); 4811da177e4SLinus Torvalds if (likely(child->sighand != NULL)) { 4821da177e4SLinus Torvalds error = -EINVAL; 4831da177e4SLinus Torvalds spin_lock_irq(&child->sighand->siglock); 4841da177e4SLinus Torvalds if (likely(child->last_siginfo != NULL)) { 485e16b2781SRoland McGrath *child->last_siginfo = *info; 4861da177e4SLinus Torvalds error = 0; 4871da177e4SLinus Torvalds } 4881da177e4SLinus Torvalds spin_unlock_irq(&child->sighand->siglock); 4891da177e4SLinus Torvalds } 4901da177e4SLinus Torvalds read_unlock(&tasklist_lock); 4911da177e4SLinus Torvalds return error; 4921da177e4SLinus Torvalds } 4931da177e4SLinus Torvalds 49436df29d7SRoland McGrath 49536df29d7SRoland McGrath #ifdef PTRACE_SINGLESTEP 49636df29d7SRoland McGrath #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) 49736df29d7SRoland McGrath #else 49836df29d7SRoland McGrath #define is_singlestep(request) 0 49936df29d7SRoland McGrath #endif 50036df29d7SRoland McGrath 5015b88abbfSRoland McGrath #ifdef PTRACE_SINGLEBLOCK 5025b88abbfSRoland McGrath #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) 5035b88abbfSRoland McGrath #else 5045b88abbfSRoland McGrath #define is_singleblock(request) 0 5055b88abbfSRoland McGrath #endif 5065b88abbfSRoland McGrath 50736df29d7SRoland McGrath #ifdef PTRACE_SYSEMU 50836df29d7SRoland McGrath #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) 50936df29d7SRoland McGrath #else 51036df29d7SRoland McGrath #define is_sysemu_singlestep(request) 0 51136df29d7SRoland McGrath #endif 51236df29d7SRoland McGrath 51336df29d7SRoland McGrath static int ptrace_resume(struct task_struct *child, long request, long data) 51436df29d7SRoland McGrath { 51536df29d7SRoland McGrath if (!valid_signal(data)) 51636df29d7SRoland McGrath return -EIO; 51736df29d7SRoland McGrath 51836df29d7SRoland McGrath if (request == PTRACE_SYSCALL) 51936df29d7SRoland McGrath set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 52036df29d7SRoland McGrath else 52136df29d7SRoland McGrath clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 52236df29d7SRoland McGrath 52336df29d7SRoland McGrath #ifdef TIF_SYSCALL_EMU 52436df29d7SRoland McGrath if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) 52536df29d7SRoland McGrath set_tsk_thread_flag(child, TIF_SYSCALL_EMU); 52636df29d7SRoland McGrath else 52736df29d7SRoland McGrath clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); 52836df29d7SRoland McGrath #endif 52936df29d7SRoland McGrath 5305b88abbfSRoland McGrath if (is_singleblock(request)) { 5315b88abbfSRoland McGrath if (unlikely(!arch_has_block_step())) 5325b88abbfSRoland McGrath return -EIO; 5335b88abbfSRoland McGrath user_enable_block_step(child); 5345b88abbfSRoland McGrath } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { 53536df29d7SRoland McGrath if (unlikely(!arch_has_single_step())) 53636df29d7SRoland McGrath return -EIO; 53736df29d7SRoland McGrath user_enable_single_step(child); 5383a709703SRoland McGrath } else { 53936df29d7SRoland McGrath user_disable_single_step(child); 5403a709703SRoland McGrath } 54136df29d7SRoland McGrath 54236df29d7SRoland McGrath child->exit_code = data; 54336df29d7SRoland McGrath wake_up_process(child); 54436df29d7SRoland McGrath 54536df29d7SRoland McGrath return 0; 54636df29d7SRoland McGrath } 54736df29d7SRoland McGrath 5481da177e4SLinus Torvalds int ptrace_request(struct task_struct *child, long request, 5491da177e4SLinus Torvalds long addr, long data) 5501da177e4SLinus Torvalds { 5511da177e4SLinus Torvalds int ret = -EIO; 552e16b2781SRoland McGrath siginfo_t siginfo; 5531da177e4SLinus Torvalds 5541da177e4SLinus Torvalds switch (request) { 55516c3e389SRoland McGrath case PTRACE_PEEKTEXT: 55616c3e389SRoland McGrath case PTRACE_PEEKDATA: 55716c3e389SRoland McGrath return generic_ptrace_peekdata(child, addr, data); 55816c3e389SRoland McGrath case PTRACE_POKETEXT: 55916c3e389SRoland McGrath case PTRACE_POKEDATA: 56016c3e389SRoland McGrath return generic_ptrace_pokedata(child, addr, data); 56116c3e389SRoland McGrath 5621da177e4SLinus Torvalds #ifdef PTRACE_OLDSETOPTIONS 5631da177e4SLinus Torvalds case PTRACE_OLDSETOPTIONS: 5641da177e4SLinus Torvalds #endif 5651da177e4SLinus Torvalds case PTRACE_SETOPTIONS: 5661da177e4SLinus Torvalds ret = ptrace_setoptions(child, data); 5671da177e4SLinus Torvalds break; 5681da177e4SLinus Torvalds case PTRACE_GETEVENTMSG: 5691da177e4SLinus Torvalds ret = put_user(child->ptrace_message, (unsigned long __user *) data); 5701da177e4SLinus Torvalds break; 571e16b2781SRoland McGrath 5721da177e4SLinus Torvalds case PTRACE_GETSIGINFO: 573e16b2781SRoland McGrath ret = ptrace_getsiginfo(child, &siginfo); 574e16b2781SRoland McGrath if (!ret) 575e16b2781SRoland McGrath ret = copy_siginfo_to_user((siginfo_t __user *) data, 576e16b2781SRoland McGrath &siginfo); 5771da177e4SLinus Torvalds break; 578e16b2781SRoland McGrath 5791da177e4SLinus Torvalds case PTRACE_SETSIGINFO: 580e16b2781SRoland McGrath if (copy_from_user(&siginfo, (siginfo_t __user *) data, 581e16b2781SRoland McGrath sizeof siginfo)) 582e16b2781SRoland McGrath ret = -EFAULT; 583e16b2781SRoland McGrath else 584e16b2781SRoland McGrath ret = ptrace_setsiginfo(child, &siginfo); 5851da177e4SLinus Torvalds break; 586e16b2781SRoland McGrath 5871bcf5482SAlexey Dobriyan case PTRACE_DETACH: /* detach a process that was attached. */ 5881bcf5482SAlexey Dobriyan ret = ptrace_detach(child, data); 5891bcf5482SAlexey Dobriyan break; 59036df29d7SRoland McGrath 59136df29d7SRoland McGrath #ifdef PTRACE_SINGLESTEP 59236df29d7SRoland McGrath case PTRACE_SINGLESTEP: 59336df29d7SRoland McGrath #endif 5945b88abbfSRoland McGrath #ifdef PTRACE_SINGLEBLOCK 5955b88abbfSRoland McGrath case PTRACE_SINGLEBLOCK: 5965b88abbfSRoland McGrath #endif 59736df29d7SRoland McGrath #ifdef PTRACE_SYSEMU 59836df29d7SRoland McGrath case PTRACE_SYSEMU: 59936df29d7SRoland McGrath case PTRACE_SYSEMU_SINGLESTEP: 60036df29d7SRoland McGrath #endif 60136df29d7SRoland McGrath case PTRACE_SYSCALL: 60236df29d7SRoland McGrath case PTRACE_CONT: 60336df29d7SRoland McGrath return ptrace_resume(child, request, data); 60436df29d7SRoland McGrath 60536df29d7SRoland McGrath case PTRACE_KILL: 60636df29d7SRoland McGrath if (child->exit_state) /* already dead */ 60736df29d7SRoland McGrath return 0; 60836df29d7SRoland McGrath return ptrace_resume(child, request, SIGKILL); 60936df29d7SRoland McGrath 6101da177e4SLinus Torvalds default: 6111da177e4SLinus Torvalds break; 6121da177e4SLinus Torvalds } 6131da177e4SLinus Torvalds 6141da177e4SLinus Torvalds return ret; 6151da177e4SLinus Torvalds } 616481bed45SChristoph Hellwig 6176b9c7ed8SChristoph Hellwig /** 6186b9c7ed8SChristoph Hellwig * ptrace_get_task_struct -- grab a task struct reference for ptrace 6196b9c7ed8SChristoph Hellwig * @pid: process id to grab a task_struct reference of 6206b9c7ed8SChristoph Hellwig * 6216b9c7ed8SChristoph Hellwig * This function is a helper for ptrace implementations. It checks 6226b9c7ed8SChristoph Hellwig * permissions and then grabs a task struct for use of the actual 6236b9c7ed8SChristoph Hellwig * ptrace implementation. 6246b9c7ed8SChristoph Hellwig * 6256b9c7ed8SChristoph Hellwig * Returns the task_struct for @pid or an ERR_PTR() on failure. 6266b9c7ed8SChristoph Hellwig */ 6276b9c7ed8SChristoph Hellwig struct task_struct *ptrace_get_task_struct(pid_t pid) 6286b9c7ed8SChristoph Hellwig { 6296b9c7ed8SChristoph Hellwig struct task_struct *child; 6306b9c7ed8SChristoph Hellwig 631481bed45SChristoph Hellwig read_lock(&tasklist_lock); 632228ebcbeSPavel Emelyanov child = find_task_by_vpid(pid); 633481bed45SChristoph Hellwig if (child) 634481bed45SChristoph Hellwig get_task_struct(child); 635f400e198SSukadev Bhattiprolu 636481bed45SChristoph Hellwig read_unlock(&tasklist_lock); 637481bed45SChristoph Hellwig if (!child) 6386b9c7ed8SChristoph Hellwig return ERR_PTR(-ESRCH); 6396b9c7ed8SChristoph Hellwig return child; 640481bed45SChristoph Hellwig } 641481bed45SChristoph Hellwig 6420ac15559SChristoph Hellwig #ifndef arch_ptrace_attach 6430ac15559SChristoph Hellwig #define arch_ptrace_attach(child) do { } while (0) 6440ac15559SChristoph Hellwig #endif 6450ac15559SChristoph Hellwig 6461e7bfb21SHeiko Carstens SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data) 647481bed45SChristoph Hellwig { 648481bed45SChristoph Hellwig struct task_struct *child; 649481bed45SChristoph Hellwig long ret; 650481bed45SChristoph Hellwig 651481bed45SChristoph Hellwig /* 652481bed45SChristoph Hellwig * This lock_kernel fixes a subtle race with suid exec 653481bed45SChristoph Hellwig */ 654481bed45SChristoph Hellwig lock_kernel(); 6556b9c7ed8SChristoph Hellwig if (request == PTRACE_TRACEME) { 6566b9c7ed8SChristoph Hellwig ret = ptrace_traceme(); 6576ea6dd93SHaavard Skinnemoen if (!ret) 6586ea6dd93SHaavard Skinnemoen arch_ptrace_attach(current); 659481bed45SChristoph Hellwig goto out; 6606b9c7ed8SChristoph Hellwig } 6616b9c7ed8SChristoph Hellwig 6626b9c7ed8SChristoph Hellwig child = ptrace_get_task_struct(pid); 6636b9c7ed8SChristoph Hellwig if (IS_ERR(child)) { 6646b9c7ed8SChristoph Hellwig ret = PTR_ERR(child); 6656b9c7ed8SChristoph Hellwig goto out; 6666b9c7ed8SChristoph Hellwig } 667481bed45SChristoph Hellwig 668481bed45SChristoph Hellwig if (request == PTRACE_ATTACH) { 669481bed45SChristoph Hellwig ret = ptrace_attach(child); 6700ac15559SChristoph Hellwig /* 6710ac15559SChristoph Hellwig * Some architectures need to do book-keeping after 6720ac15559SChristoph Hellwig * a ptrace attach. 6730ac15559SChristoph Hellwig */ 6740ac15559SChristoph Hellwig if (!ret) 6750ac15559SChristoph Hellwig arch_ptrace_attach(child); 676005f18dfSChristoph Hellwig goto out_put_task_struct; 677481bed45SChristoph Hellwig } 678481bed45SChristoph Hellwig 679481bed45SChristoph Hellwig ret = ptrace_check_attach(child, request == PTRACE_KILL); 680481bed45SChristoph Hellwig if (ret < 0) 681481bed45SChristoph Hellwig goto out_put_task_struct; 682481bed45SChristoph Hellwig 683481bed45SChristoph Hellwig ret = arch_ptrace(child, request, addr, data); 684481bed45SChristoph Hellwig 685481bed45SChristoph Hellwig out_put_task_struct: 686481bed45SChristoph Hellwig put_task_struct(child); 687481bed45SChristoph Hellwig out: 688481bed45SChristoph Hellwig unlock_kernel(); 689481bed45SChristoph Hellwig return ret; 690481bed45SChristoph Hellwig } 69176647323SAlexey Dobriyan 69276647323SAlexey Dobriyan int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data) 69376647323SAlexey Dobriyan { 69476647323SAlexey Dobriyan unsigned long tmp; 69576647323SAlexey Dobriyan int copied; 69676647323SAlexey Dobriyan 69776647323SAlexey Dobriyan copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); 69876647323SAlexey Dobriyan if (copied != sizeof(tmp)) 69976647323SAlexey Dobriyan return -EIO; 70076647323SAlexey Dobriyan return put_user(tmp, (unsigned long __user *)data); 70176647323SAlexey Dobriyan } 702f284ce72SAlexey Dobriyan 703f284ce72SAlexey Dobriyan int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data) 704f284ce72SAlexey Dobriyan { 705f284ce72SAlexey Dobriyan int copied; 706f284ce72SAlexey Dobriyan 707f284ce72SAlexey Dobriyan copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); 708f284ce72SAlexey Dobriyan return (copied == sizeof(data)) ? 0 : -EIO; 709f284ce72SAlexey Dobriyan } 710032d82d9SRoland McGrath 71196b8936aSChristoph Hellwig #if defined CONFIG_COMPAT 712032d82d9SRoland McGrath #include <linux/compat.h> 713032d82d9SRoland McGrath 714032d82d9SRoland McGrath int compat_ptrace_request(struct task_struct *child, compat_long_t request, 715032d82d9SRoland McGrath compat_ulong_t addr, compat_ulong_t data) 716032d82d9SRoland McGrath { 717032d82d9SRoland McGrath compat_ulong_t __user *datap = compat_ptr(data); 718032d82d9SRoland McGrath compat_ulong_t word; 719e16b2781SRoland McGrath siginfo_t siginfo; 720032d82d9SRoland McGrath int ret; 721032d82d9SRoland McGrath 722032d82d9SRoland McGrath switch (request) { 723032d82d9SRoland McGrath case PTRACE_PEEKTEXT: 724032d82d9SRoland McGrath case PTRACE_PEEKDATA: 725032d82d9SRoland McGrath ret = access_process_vm(child, addr, &word, sizeof(word), 0); 726032d82d9SRoland McGrath if (ret != sizeof(word)) 727032d82d9SRoland McGrath ret = -EIO; 728032d82d9SRoland McGrath else 729032d82d9SRoland McGrath ret = put_user(word, datap); 730032d82d9SRoland McGrath break; 731032d82d9SRoland McGrath 732032d82d9SRoland McGrath case PTRACE_POKETEXT: 733032d82d9SRoland McGrath case PTRACE_POKEDATA: 734032d82d9SRoland McGrath ret = access_process_vm(child, addr, &data, sizeof(data), 1); 735032d82d9SRoland McGrath ret = (ret != sizeof(data) ? -EIO : 0); 736032d82d9SRoland McGrath break; 737032d82d9SRoland McGrath 738032d82d9SRoland McGrath case PTRACE_GETEVENTMSG: 739032d82d9SRoland McGrath ret = put_user((compat_ulong_t) child->ptrace_message, datap); 740032d82d9SRoland McGrath break; 741032d82d9SRoland McGrath 742e16b2781SRoland McGrath case PTRACE_GETSIGINFO: 743e16b2781SRoland McGrath ret = ptrace_getsiginfo(child, &siginfo); 744e16b2781SRoland McGrath if (!ret) 745e16b2781SRoland McGrath ret = copy_siginfo_to_user32( 746e16b2781SRoland McGrath (struct compat_siginfo __user *) datap, 747e16b2781SRoland McGrath &siginfo); 748e16b2781SRoland McGrath break; 749e16b2781SRoland McGrath 750e16b2781SRoland McGrath case PTRACE_SETSIGINFO: 751e16b2781SRoland McGrath memset(&siginfo, 0, sizeof siginfo); 752e16b2781SRoland McGrath if (copy_siginfo_from_user32( 753e16b2781SRoland McGrath &siginfo, (struct compat_siginfo __user *) datap)) 754e16b2781SRoland McGrath ret = -EFAULT; 755e16b2781SRoland McGrath else 756e16b2781SRoland McGrath ret = ptrace_setsiginfo(child, &siginfo); 757e16b2781SRoland McGrath break; 758e16b2781SRoland McGrath 759032d82d9SRoland McGrath default: 760032d82d9SRoland McGrath ret = ptrace_request(child, request, addr, data); 761032d82d9SRoland McGrath } 762032d82d9SRoland McGrath 763032d82d9SRoland McGrath return ret; 764032d82d9SRoland McGrath } 765c269f196SRoland McGrath 766c269f196SRoland McGrath asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, 767c269f196SRoland McGrath compat_long_t addr, compat_long_t data) 768c269f196SRoland McGrath { 769c269f196SRoland McGrath struct task_struct *child; 770c269f196SRoland McGrath long ret; 771c269f196SRoland McGrath 772c269f196SRoland McGrath /* 773c269f196SRoland McGrath * This lock_kernel fixes a subtle race with suid exec 774c269f196SRoland McGrath */ 775c269f196SRoland McGrath lock_kernel(); 776c269f196SRoland McGrath if (request == PTRACE_TRACEME) { 777c269f196SRoland McGrath ret = ptrace_traceme(); 778c269f196SRoland McGrath goto out; 779c269f196SRoland McGrath } 780c269f196SRoland McGrath 781c269f196SRoland McGrath child = ptrace_get_task_struct(pid); 782c269f196SRoland McGrath if (IS_ERR(child)) { 783c269f196SRoland McGrath ret = PTR_ERR(child); 784c269f196SRoland McGrath goto out; 785c269f196SRoland McGrath } 786c269f196SRoland McGrath 787c269f196SRoland McGrath if (request == PTRACE_ATTACH) { 788c269f196SRoland McGrath ret = ptrace_attach(child); 789c269f196SRoland McGrath /* 790c269f196SRoland McGrath * Some architectures need to do book-keeping after 791c269f196SRoland McGrath * a ptrace attach. 792c269f196SRoland McGrath */ 793c269f196SRoland McGrath if (!ret) 794c269f196SRoland McGrath arch_ptrace_attach(child); 795c269f196SRoland McGrath goto out_put_task_struct; 796c269f196SRoland McGrath } 797c269f196SRoland McGrath 798c269f196SRoland McGrath ret = ptrace_check_attach(child, request == PTRACE_KILL); 799c269f196SRoland McGrath if (!ret) 800c269f196SRoland McGrath ret = compat_arch_ptrace(child, request, addr, data); 801c269f196SRoland McGrath 802c269f196SRoland McGrath out_put_task_struct: 803c269f196SRoland McGrath put_task_struct(child); 804c269f196SRoland McGrath out: 805c269f196SRoland McGrath unlock_kernel(); 806c269f196SRoland McGrath return ret; 807c269f196SRoland McGrath } 80896b8936aSChristoph Hellwig #endif /* CONFIG_COMPAT */ 809