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> 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds #include <asm/pgtable.h> 231da177e4SLinus Torvalds #include <asm/uaccess.h> 241da177e4SLinus Torvalds 251da177e4SLinus Torvalds /* 261da177e4SLinus Torvalds * ptrace a task: make the debugger its new parent and 271da177e4SLinus Torvalds * move it to the ptrace list. 281da177e4SLinus Torvalds * 291da177e4SLinus Torvalds * Must be called with the tasklist lock write-held. 301da177e4SLinus Torvalds */ 311da177e4SLinus Torvalds void __ptrace_link(task_t *child, task_t *new_parent) 321da177e4SLinus Torvalds { 33524223caSEric Sesterhenn BUG_ON(!list_empty(&child->ptrace_list)); 341da177e4SLinus Torvalds if (child->parent == new_parent) 351da177e4SLinus Torvalds return; 361da177e4SLinus Torvalds list_add(&child->ptrace_list, &child->parent->ptrace_children); 379b678eceSOleg Nesterov remove_parent(child); 381da177e4SLinus Torvalds child->parent = new_parent; 399b678eceSOleg Nesterov add_parent(child); 401da177e4SLinus Torvalds } 411da177e4SLinus Torvalds 421da177e4SLinus Torvalds /* 431da177e4SLinus Torvalds * Turn a tracing stop into a normal stop now, since with no tracer there 441da177e4SLinus Torvalds * would be no way to wake it up with SIGCONT or SIGKILL. If there was a 451da177e4SLinus Torvalds * signal sent that would resume the child, but didn't because it was in 461da177e4SLinus Torvalds * TASK_TRACED, resume it now. 471da177e4SLinus Torvalds * Requires that irqs be disabled. 481da177e4SLinus Torvalds */ 491da177e4SLinus Torvalds void ptrace_untrace(task_t *child) 501da177e4SLinus Torvalds { 511da177e4SLinus Torvalds spin_lock(&child->sighand->siglock); 521da177e4SLinus Torvalds if (child->state == TASK_TRACED) { 531da177e4SLinus Torvalds if (child->signal->flags & SIGNAL_STOP_STOPPED) { 541da177e4SLinus Torvalds child->state = TASK_STOPPED; 551da177e4SLinus Torvalds } else { 561da177e4SLinus Torvalds signal_wake_up(child, 1); 571da177e4SLinus Torvalds } 581da177e4SLinus Torvalds } 591da177e4SLinus Torvalds spin_unlock(&child->sighand->siglock); 601da177e4SLinus Torvalds } 611da177e4SLinus Torvalds 621da177e4SLinus Torvalds /* 631da177e4SLinus Torvalds * unptrace a task: move it back to its original parent and 641da177e4SLinus Torvalds * remove it from the ptrace list. 651da177e4SLinus Torvalds * 661da177e4SLinus Torvalds * Must be called with the tasklist lock write-held. 671da177e4SLinus Torvalds */ 681da177e4SLinus Torvalds void __ptrace_unlink(task_t *child) 691da177e4SLinus Torvalds { 705ecfbae0SOleg Nesterov BUG_ON(!child->ptrace); 715ecfbae0SOleg Nesterov 721da177e4SLinus Torvalds child->ptrace = 0; 731da177e4SLinus Torvalds if (!list_empty(&child->ptrace_list)) { 741da177e4SLinus Torvalds list_del_init(&child->ptrace_list); 759b678eceSOleg Nesterov remove_parent(child); 761da177e4SLinus Torvalds child->parent = child->real_parent; 779b678eceSOleg Nesterov add_parent(child); 781da177e4SLinus Torvalds } 791da177e4SLinus Torvalds 80e57a5059SRoland McGrath if (child->state == TASK_TRACED) 811da177e4SLinus Torvalds ptrace_untrace(child); 821da177e4SLinus Torvalds } 831da177e4SLinus Torvalds 841da177e4SLinus Torvalds /* 851da177e4SLinus Torvalds * Check that we have indeed attached to the thing.. 861da177e4SLinus Torvalds */ 871da177e4SLinus Torvalds int ptrace_check_attach(struct task_struct *child, int kill) 881da177e4SLinus Torvalds { 891da177e4SLinus Torvalds int ret = -ESRCH; 901da177e4SLinus Torvalds 911da177e4SLinus Torvalds /* 921da177e4SLinus Torvalds * We take the read lock around doing both checks to close a 931da177e4SLinus Torvalds * possible race where someone else was tracing our child and 941da177e4SLinus Torvalds * detached between these two checks. After this locked check, 951da177e4SLinus Torvalds * we are sure that this is our traced child and that can only 961da177e4SLinus Torvalds * be changed by us so it's not changing right after this. 971da177e4SLinus Torvalds */ 981da177e4SLinus Torvalds read_lock(&tasklist_lock); 991da177e4SLinus Torvalds if ((child->ptrace & PT_PTRACED) && child->parent == current && 1001da177e4SLinus Torvalds (!(child->ptrace & PT_ATTACHED) || child->real_parent != current) 1011da177e4SLinus Torvalds && child->signal != NULL) { 1021da177e4SLinus Torvalds ret = 0; 1031da177e4SLinus Torvalds spin_lock_irq(&child->sighand->siglock); 1041da177e4SLinus Torvalds if (child->state == TASK_STOPPED) { 1051da177e4SLinus Torvalds child->state = TASK_TRACED; 1061da177e4SLinus Torvalds } else if (child->state != TASK_TRACED && !kill) { 1071da177e4SLinus Torvalds ret = -ESRCH; 1081da177e4SLinus Torvalds } 1091da177e4SLinus Torvalds spin_unlock_irq(&child->sighand->siglock); 1101da177e4SLinus Torvalds } 1111da177e4SLinus Torvalds read_unlock(&tasklist_lock); 1121da177e4SLinus Torvalds 1131da177e4SLinus Torvalds if (!ret && !kill) { 1141da177e4SLinus Torvalds wait_task_inactive(child); 1151da177e4SLinus Torvalds } 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds /* All systems go.. */ 1181da177e4SLinus Torvalds return ret; 1191da177e4SLinus Torvalds } 1201da177e4SLinus Torvalds 121ab8d11beSMiklos Szeredi static int may_attach(struct task_struct *task) 122ab8d11beSMiklos Szeredi { 123df26c40eSEric W. Biederman /* May we inspect the given task? 124df26c40eSEric W. Biederman * This check is used both for attaching with ptrace 125df26c40eSEric W. Biederman * and for allowing access to sensitive information in /proc. 126df26c40eSEric W. Biederman * 127df26c40eSEric W. Biederman * ptrace_attach denies several cases that /proc allows 128df26c40eSEric W. Biederman * because setting up the necessary parent/child relationship 129df26c40eSEric W. Biederman * or halting the specified task is impossible. 130df26c40eSEric W. Biederman */ 131df26c40eSEric W. Biederman int dumpable = 0; 132df26c40eSEric W. Biederman /* Don't let security modules deny introspection */ 133df26c40eSEric W. Biederman if (task == current) 134df26c40eSEric W. Biederman return 0; 135ab8d11beSMiklos Szeredi if (((current->uid != task->euid) || 136ab8d11beSMiklos Szeredi (current->uid != task->suid) || 137ab8d11beSMiklos Szeredi (current->uid != task->uid) || 138ab8d11beSMiklos Szeredi (current->gid != task->egid) || 139ab8d11beSMiklos Szeredi (current->gid != task->sgid) || 140ab8d11beSMiklos Szeredi (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE)) 141ab8d11beSMiklos Szeredi return -EPERM; 142ab8d11beSMiklos Szeredi smp_rmb(); 143df26c40eSEric W. Biederman if (task->mm) 144df26c40eSEric W. Biederman dumpable = task->mm->dumpable; 145df26c40eSEric W. Biederman if (!dumpable && !capable(CAP_SYS_PTRACE)) 146ab8d11beSMiklos Szeredi return -EPERM; 147ab8d11beSMiklos Szeredi 148ab8d11beSMiklos Szeredi return security_ptrace(current, task); 149ab8d11beSMiklos Szeredi } 150ab8d11beSMiklos Szeredi 151ab8d11beSMiklos Szeredi int ptrace_may_attach(struct task_struct *task) 152ab8d11beSMiklos Szeredi { 153ab8d11beSMiklos Szeredi int err; 154ab8d11beSMiklos Szeredi task_lock(task); 155ab8d11beSMiklos Szeredi err = may_attach(task); 156ab8d11beSMiklos Szeredi task_unlock(task); 157ab8d11beSMiklos Szeredi return !err; 158ab8d11beSMiklos Szeredi } 159ab8d11beSMiklos Szeredi 1601da177e4SLinus Torvalds int ptrace_attach(struct task_struct *task) 1611da177e4SLinus Torvalds { 1621da177e4SLinus Torvalds int retval; 163f5b40e36SLinus Torvalds 1641da177e4SLinus Torvalds retval = -EPERM; 1651da177e4SLinus Torvalds if (task->pid <= 1) 166f5b40e36SLinus Torvalds goto out; 16728d838ccSLinus Torvalds if (task->tgid == current->tgid) 168f5b40e36SLinus Torvalds goto out; 169f5b40e36SLinus Torvalds 170f358166aSLinus Torvalds repeat: 171f358166aSLinus Torvalds /* 172f358166aSLinus Torvalds * Nasty, nasty. 173f358166aSLinus Torvalds * 174f358166aSLinus Torvalds * We want to hold both the task-lock and the 175f358166aSLinus Torvalds * tasklist_lock for writing at the same time. 176f358166aSLinus Torvalds * But that's against the rules (tasklist_lock 177f358166aSLinus Torvalds * is taken for reading by interrupts on other 178f358166aSLinus Torvalds * cpu's that may have task_lock). 179f358166aSLinus Torvalds */ 180f5b40e36SLinus Torvalds task_lock(task); 181f358166aSLinus Torvalds local_irq_disable(); 182f358166aSLinus Torvalds if (!write_trylock(&tasklist_lock)) { 183f358166aSLinus Torvalds local_irq_enable(); 184f358166aSLinus Torvalds task_unlock(task); 185f358166aSLinus Torvalds do { 186f358166aSLinus Torvalds cpu_relax(); 187f358166aSLinus Torvalds } while (!write_can_lock(&tasklist_lock)); 188f358166aSLinus Torvalds goto repeat; 189f358166aSLinus Torvalds } 190f5b40e36SLinus Torvalds 191df26c40eSEric W. Biederman if (!task->mm) 192df26c40eSEric W. Biederman goto bad; 1931da177e4SLinus Torvalds /* the same process cannot be attached many times */ 1941da177e4SLinus Torvalds if (task->ptrace & PT_PTRACED) 1951da177e4SLinus Torvalds goto bad; 196ab8d11beSMiklos Szeredi retval = may_attach(task); 1971da177e4SLinus Torvalds if (retval) 1981da177e4SLinus Torvalds goto bad; 1991da177e4SLinus Torvalds 2001da177e4SLinus Torvalds /* Go */ 2011da177e4SLinus Torvalds task->ptrace |= PT_PTRACED | ((task->real_parent != current) 2021da177e4SLinus Torvalds ? PT_ATTACHED : 0); 2031da177e4SLinus Torvalds if (capable(CAP_SYS_PTRACE)) 2041da177e4SLinus Torvalds task->ptrace |= PT_PTRACE_CAP; 2051da177e4SLinus Torvalds 2061da177e4SLinus Torvalds __ptrace_link(task, current); 2071da177e4SLinus Torvalds 2081da177e4SLinus Torvalds force_sig_specific(SIGSTOP, task); 2091da177e4SLinus Torvalds 2101da177e4SLinus Torvalds bad: 211f5b40e36SLinus Torvalds write_unlock_irq(&tasklist_lock); 2121da177e4SLinus Torvalds task_unlock(task); 213f5b40e36SLinus Torvalds out: 2141da177e4SLinus Torvalds return retval; 2151da177e4SLinus Torvalds } 2161da177e4SLinus Torvalds 2175ecfbae0SOleg Nesterov void __ptrace_detach(struct task_struct *child, unsigned int data) 2185ecfbae0SOleg Nesterov { 2195ecfbae0SOleg Nesterov child->exit_code = data; 2205ecfbae0SOleg Nesterov /* .. re-parent .. */ 2215ecfbae0SOleg Nesterov __ptrace_unlink(child); 2225ecfbae0SOleg Nesterov /* .. and wake it up. */ 2235ecfbae0SOleg Nesterov if (child->exit_state != EXIT_ZOMBIE) 2245ecfbae0SOleg Nesterov wake_up_process(child); 2255ecfbae0SOleg Nesterov } 2265ecfbae0SOleg Nesterov 2271da177e4SLinus Torvalds int ptrace_detach(struct task_struct *child, unsigned int data) 2281da177e4SLinus Torvalds { 2297ed20e1aSJesper Juhl if (!valid_signal(data)) 2301da177e4SLinus Torvalds return -EIO; 2311da177e4SLinus Torvalds 2321da177e4SLinus Torvalds /* Architecture-specific hardware disable .. */ 2331da177e4SLinus Torvalds ptrace_disable(child); 2341da177e4SLinus Torvalds 2351da177e4SLinus Torvalds write_lock_irq(&tasklist_lock); 2365ecfbae0SOleg Nesterov if (child->ptrace) 2375ecfbae0SOleg Nesterov __ptrace_detach(child, data); 2381da177e4SLinus Torvalds write_unlock_irq(&tasklist_lock); 2391da177e4SLinus Torvalds 2401da177e4SLinus Torvalds return 0; 2411da177e4SLinus Torvalds } 2421da177e4SLinus Torvalds 2431da177e4SLinus Torvalds /* 2441da177e4SLinus Torvalds * Access another process' address space. 2451da177e4SLinus Torvalds * Source/target buffer must be kernel space, 2461da177e4SLinus Torvalds * Do not walk the page table directly, use get_user_pages 2471da177e4SLinus Torvalds */ 2481da177e4SLinus Torvalds 2491da177e4SLinus Torvalds int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) 2501da177e4SLinus Torvalds { 2511da177e4SLinus Torvalds struct mm_struct *mm; 2521da177e4SLinus Torvalds struct vm_area_struct *vma; 2531da177e4SLinus Torvalds struct page *page; 2541da177e4SLinus Torvalds void *old_buf = buf; 2551da177e4SLinus Torvalds 2561da177e4SLinus Torvalds mm = get_task_mm(tsk); 2571da177e4SLinus Torvalds if (!mm) 2581da177e4SLinus Torvalds return 0; 2591da177e4SLinus Torvalds 2601da177e4SLinus Torvalds down_read(&mm->mmap_sem); 2611da177e4SLinus Torvalds /* ignore errors, just check how much was sucessfully transfered */ 2621da177e4SLinus Torvalds while (len) { 2631da177e4SLinus Torvalds int bytes, ret, offset; 2641da177e4SLinus Torvalds void *maddr; 2651da177e4SLinus Torvalds 2661da177e4SLinus Torvalds ret = get_user_pages(tsk, mm, addr, 1, 2671da177e4SLinus Torvalds write, 1, &page, &vma); 2681da177e4SLinus Torvalds if (ret <= 0) 2691da177e4SLinus Torvalds break; 2701da177e4SLinus Torvalds 2711da177e4SLinus Torvalds bytes = len; 2721da177e4SLinus Torvalds offset = addr & (PAGE_SIZE-1); 2731da177e4SLinus Torvalds if (bytes > PAGE_SIZE-offset) 2741da177e4SLinus Torvalds bytes = PAGE_SIZE-offset; 2751da177e4SLinus Torvalds 2761da177e4SLinus Torvalds maddr = kmap(page); 2771da177e4SLinus Torvalds if (write) { 2781da177e4SLinus Torvalds copy_to_user_page(vma, page, addr, 2791da177e4SLinus Torvalds maddr + offset, buf, bytes); 2801da177e4SLinus Torvalds set_page_dirty_lock(page); 2811da177e4SLinus Torvalds } else { 2821da177e4SLinus Torvalds copy_from_user_page(vma, page, addr, 2831da177e4SLinus Torvalds buf, maddr + offset, bytes); 2841da177e4SLinus Torvalds } 2851da177e4SLinus Torvalds kunmap(page); 2861da177e4SLinus Torvalds page_cache_release(page); 2871da177e4SLinus Torvalds len -= bytes; 2881da177e4SLinus Torvalds buf += bytes; 2891da177e4SLinus Torvalds addr += bytes; 2901da177e4SLinus Torvalds } 2911da177e4SLinus Torvalds up_read(&mm->mmap_sem); 2921da177e4SLinus Torvalds mmput(mm); 2931da177e4SLinus Torvalds 2941da177e4SLinus Torvalds return buf - old_buf; 2951da177e4SLinus Torvalds } 2961da177e4SLinus Torvalds 2971da177e4SLinus Torvalds int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) 2981da177e4SLinus Torvalds { 2991da177e4SLinus Torvalds int copied = 0; 3001da177e4SLinus Torvalds 3011da177e4SLinus Torvalds while (len > 0) { 3021da177e4SLinus Torvalds char buf[128]; 3031da177e4SLinus Torvalds int this_len, retval; 3041da177e4SLinus Torvalds 3051da177e4SLinus Torvalds this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 3061da177e4SLinus Torvalds retval = access_process_vm(tsk, src, buf, this_len, 0); 3071da177e4SLinus Torvalds if (!retval) { 3081da177e4SLinus Torvalds if (copied) 3091da177e4SLinus Torvalds break; 3101da177e4SLinus Torvalds return -EIO; 3111da177e4SLinus Torvalds } 3121da177e4SLinus Torvalds if (copy_to_user(dst, buf, retval)) 3131da177e4SLinus Torvalds return -EFAULT; 3141da177e4SLinus Torvalds copied += retval; 3151da177e4SLinus Torvalds src += retval; 3161da177e4SLinus Torvalds dst += retval; 3171da177e4SLinus Torvalds len -= retval; 3181da177e4SLinus Torvalds } 3191da177e4SLinus Torvalds return copied; 3201da177e4SLinus Torvalds } 3211da177e4SLinus Torvalds 3221da177e4SLinus Torvalds int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) 3231da177e4SLinus Torvalds { 3241da177e4SLinus Torvalds int copied = 0; 3251da177e4SLinus Torvalds 3261da177e4SLinus Torvalds while (len > 0) { 3271da177e4SLinus Torvalds char buf[128]; 3281da177e4SLinus Torvalds int this_len, retval; 3291da177e4SLinus Torvalds 3301da177e4SLinus Torvalds this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 3311da177e4SLinus Torvalds if (copy_from_user(buf, src, this_len)) 3321da177e4SLinus Torvalds return -EFAULT; 3331da177e4SLinus Torvalds retval = access_process_vm(tsk, dst, buf, this_len, 1); 3341da177e4SLinus Torvalds if (!retval) { 3351da177e4SLinus Torvalds if (copied) 3361da177e4SLinus Torvalds break; 3371da177e4SLinus Torvalds return -EIO; 3381da177e4SLinus Torvalds } 3391da177e4SLinus Torvalds copied += retval; 3401da177e4SLinus Torvalds src += retval; 3411da177e4SLinus Torvalds dst += retval; 3421da177e4SLinus Torvalds len -= retval; 3431da177e4SLinus Torvalds } 3441da177e4SLinus Torvalds return copied; 3451da177e4SLinus Torvalds } 3461da177e4SLinus Torvalds 3471da177e4SLinus Torvalds static int ptrace_setoptions(struct task_struct *child, long data) 3481da177e4SLinus Torvalds { 3491da177e4SLinus Torvalds child->ptrace &= ~PT_TRACE_MASK; 3501da177e4SLinus Torvalds 3511da177e4SLinus Torvalds if (data & PTRACE_O_TRACESYSGOOD) 3521da177e4SLinus Torvalds child->ptrace |= PT_TRACESYSGOOD; 3531da177e4SLinus Torvalds 3541da177e4SLinus Torvalds if (data & PTRACE_O_TRACEFORK) 3551da177e4SLinus Torvalds child->ptrace |= PT_TRACE_FORK; 3561da177e4SLinus Torvalds 3571da177e4SLinus Torvalds if (data & PTRACE_O_TRACEVFORK) 3581da177e4SLinus Torvalds child->ptrace |= PT_TRACE_VFORK; 3591da177e4SLinus Torvalds 3601da177e4SLinus Torvalds if (data & PTRACE_O_TRACECLONE) 3611da177e4SLinus Torvalds child->ptrace |= PT_TRACE_CLONE; 3621da177e4SLinus Torvalds 3631da177e4SLinus Torvalds if (data & PTRACE_O_TRACEEXEC) 3641da177e4SLinus Torvalds child->ptrace |= PT_TRACE_EXEC; 3651da177e4SLinus Torvalds 3661da177e4SLinus Torvalds if (data & PTRACE_O_TRACEVFORKDONE) 3671da177e4SLinus Torvalds child->ptrace |= PT_TRACE_VFORK_DONE; 3681da177e4SLinus Torvalds 3691da177e4SLinus Torvalds if (data & PTRACE_O_TRACEEXIT) 3701da177e4SLinus Torvalds child->ptrace |= PT_TRACE_EXIT; 3711da177e4SLinus Torvalds 3721da177e4SLinus Torvalds return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; 3731da177e4SLinus Torvalds } 3741da177e4SLinus Torvalds 3751da177e4SLinus Torvalds static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data) 3761da177e4SLinus Torvalds { 3771da177e4SLinus Torvalds siginfo_t lastinfo; 3781da177e4SLinus Torvalds int error = -ESRCH; 3791da177e4SLinus Torvalds 3801da177e4SLinus Torvalds read_lock(&tasklist_lock); 3811da177e4SLinus Torvalds if (likely(child->sighand != NULL)) { 3821da177e4SLinus Torvalds error = -EINVAL; 3831da177e4SLinus Torvalds spin_lock_irq(&child->sighand->siglock); 3841da177e4SLinus Torvalds if (likely(child->last_siginfo != NULL)) { 3851da177e4SLinus Torvalds lastinfo = *child->last_siginfo; 3861da177e4SLinus Torvalds error = 0; 3871da177e4SLinus Torvalds } 3881da177e4SLinus Torvalds spin_unlock_irq(&child->sighand->siglock); 3891da177e4SLinus Torvalds } 3901da177e4SLinus Torvalds read_unlock(&tasklist_lock); 3911da177e4SLinus Torvalds if (!error) 3921da177e4SLinus Torvalds return copy_siginfo_to_user(data, &lastinfo); 3931da177e4SLinus Torvalds return error; 3941da177e4SLinus Torvalds } 3951da177e4SLinus Torvalds 3961da177e4SLinus Torvalds static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data) 3971da177e4SLinus Torvalds { 3981da177e4SLinus Torvalds siginfo_t newinfo; 3991da177e4SLinus Torvalds int error = -ESRCH; 4001da177e4SLinus Torvalds 4011da177e4SLinus Torvalds if (copy_from_user(&newinfo, data, sizeof (siginfo_t))) 4021da177e4SLinus Torvalds return -EFAULT; 4031da177e4SLinus Torvalds 4041da177e4SLinus Torvalds read_lock(&tasklist_lock); 4051da177e4SLinus Torvalds if (likely(child->sighand != NULL)) { 4061da177e4SLinus Torvalds error = -EINVAL; 4071da177e4SLinus Torvalds spin_lock_irq(&child->sighand->siglock); 4081da177e4SLinus Torvalds if (likely(child->last_siginfo != NULL)) { 4091da177e4SLinus Torvalds *child->last_siginfo = newinfo; 4101da177e4SLinus Torvalds error = 0; 4111da177e4SLinus Torvalds } 4121da177e4SLinus Torvalds spin_unlock_irq(&child->sighand->siglock); 4131da177e4SLinus Torvalds } 4141da177e4SLinus Torvalds read_unlock(&tasklist_lock); 4151da177e4SLinus Torvalds return error; 4161da177e4SLinus Torvalds } 4171da177e4SLinus Torvalds 4181da177e4SLinus Torvalds int ptrace_request(struct task_struct *child, long request, 4191da177e4SLinus Torvalds long addr, long data) 4201da177e4SLinus Torvalds { 4211da177e4SLinus Torvalds int ret = -EIO; 4221da177e4SLinus Torvalds 4231da177e4SLinus Torvalds switch (request) { 4241da177e4SLinus Torvalds #ifdef PTRACE_OLDSETOPTIONS 4251da177e4SLinus Torvalds case PTRACE_OLDSETOPTIONS: 4261da177e4SLinus Torvalds #endif 4271da177e4SLinus Torvalds case PTRACE_SETOPTIONS: 4281da177e4SLinus Torvalds ret = ptrace_setoptions(child, data); 4291da177e4SLinus Torvalds break; 4301da177e4SLinus Torvalds case PTRACE_GETEVENTMSG: 4311da177e4SLinus Torvalds ret = put_user(child->ptrace_message, (unsigned long __user *) data); 4321da177e4SLinus Torvalds break; 4331da177e4SLinus Torvalds case PTRACE_GETSIGINFO: 4341da177e4SLinus Torvalds ret = ptrace_getsiginfo(child, (siginfo_t __user *) data); 4351da177e4SLinus Torvalds break; 4361da177e4SLinus Torvalds case PTRACE_SETSIGINFO: 4371da177e4SLinus Torvalds ret = ptrace_setsiginfo(child, (siginfo_t __user *) data); 4381da177e4SLinus Torvalds break; 4391da177e4SLinus Torvalds default: 4401da177e4SLinus Torvalds break; 4411da177e4SLinus Torvalds } 4421da177e4SLinus Torvalds 4431da177e4SLinus Torvalds return ret; 4441da177e4SLinus Torvalds } 445481bed45SChristoph Hellwig 4466b9c7ed8SChristoph Hellwig /** 4476b9c7ed8SChristoph Hellwig * ptrace_traceme -- helper for PTRACE_TRACEME 4486b9c7ed8SChristoph Hellwig * 4496b9c7ed8SChristoph Hellwig * Performs checks and sets PT_PTRACED. 4506b9c7ed8SChristoph Hellwig * Should be used by all ptrace implementations for PTRACE_TRACEME. 4516b9c7ed8SChristoph Hellwig */ 4526b9c7ed8SChristoph Hellwig int ptrace_traceme(void) 453481bed45SChristoph Hellwig { 454f5b40e36SLinus Torvalds int ret = -EPERM; 455481bed45SChristoph Hellwig 456481bed45SChristoph Hellwig /* 457481bed45SChristoph Hellwig * Are we already being traced? 458481bed45SChristoph Hellwig */ 459f5b40e36SLinus Torvalds task_lock(current); 460f5b40e36SLinus Torvalds if (!(current->ptrace & PT_PTRACED)) { 461481bed45SChristoph Hellwig ret = security_ptrace(current->parent, current); 462481bed45SChristoph Hellwig /* 463481bed45SChristoph Hellwig * Set the ptrace bit in the process ptrace flags. 464481bed45SChristoph Hellwig */ 465f5b40e36SLinus Torvalds if (!ret) 466481bed45SChristoph Hellwig current->ptrace |= PT_PTRACED; 467f5b40e36SLinus Torvalds } 468f5b40e36SLinus Torvalds task_unlock(current); 469f5b40e36SLinus Torvalds return ret; 470481bed45SChristoph Hellwig } 471481bed45SChristoph Hellwig 4726b9c7ed8SChristoph Hellwig /** 4736b9c7ed8SChristoph Hellwig * ptrace_get_task_struct -- grab a task struct reference for ptrace 4746b9c7ed8SChristoph Hellwig * @pid: process id to grab a task_struct reference of 4756b9c7ed8SChristoph Hellwig * 4766b9c7ed8SChristoph Hellwig * This function is a helper for ptrace implementations. It checks 4776b9c7ed8SChristoph Hellwig * permissions and then grabs a task struct for use of the actual 4786b9c7ed8SChristoph Hellwig * ptrace implementation. 4796b9c7ed8SChristoph Hellwig * 4806b9c7ed8SChristoph Hellwig * Returns the task_struct for @pid or an ERR_PTR() on failure. 4816b9c7ed8SChristoph Hellwig */ 4826b9c7ed8SChristoph Hellwig struct task_struct *ptrace_get_task_struct(pid_t pid) 4836b9c7ed8SChristoph Hellwig { 4846b9c7ed8SChristoph Hellwig struct task_struct *child; 4856b9c7ed8SChristoph Hellwig 486481bed45SChristoph Hellwig /* 4876b9c7ed8SChristoph Hellwig * Tracing init is not allowed. 488481bed45SChristoph Hellwig */ 489481bed45SChristoph Hellwig if (pid == 1) 4906b9c7ed8SChristoph Hellwig return ERR_PTR(-EPERM); 491481bed45SChristoph Hellwig 492481bed45SChristoph Hellwig read_lock(&tasklist_lock); 493481bed45SChristoph Hellwig child = find_task_by_pid(pid); 494481bed45SChristoph Hellwig if (child) 495481bed45SChristoph Hellwig get_task_struct(child); 496481bed45SChristoph Hellwig read_unlock(&tasklist_lock); 497481bed45SChristoph Hellwig if (!child) 4986b9c7ed8SChristoph Hellwig return ERR_PTR(-ESRCH); 4996b9c7ed8SChristoph Hellwig return child; 500481bed45SChristoph Hellwig } 501481bed45SChristoph Hellwig 5026b9c7ed8SChristoph Hellwig #ifndef __ARCH_SYS_PTRACE 503481bed45SChristoph Hellwig asmlinkage long sys_ptrace(long request, long pid, long addr, long data) 504481bed45SChristoph Hellwig { 505481bed45SChristoph Hellwig struct task_struct *child; 506481bed45SChristoph Hellwig long ret; 507481bed45SChristoph Hellwig 508481bed45SChristoph Hellwig /* 509481bed45SChristoph Hellwig * This lock_kernel fixes a subtle race with suid exec 510481bed45SChristoph Hellwig */ 511481bed45SChristoph Hellwig lock_kernel(); 5126b9c7ed8SChristoph Hellwig if (request == PTRACE_TRACEME) { 5136b9c7ed8SChristoph Hellwig ret = ptrace_traceme(); 514481bed45SChristoph Hellwig goto out; 5156b9c7ed8SChristoph Hellwig } 5166b9c7ed8SChristoph Hellwig 5176b9c7ed8SChristoph Hellwig child = ptrace_get_task_struct(pid); 5186b9c7ed8SChristoph Hellwig if (IS_ERR(child)) { 5196b9c7ed8SChristoph Hellwig ret = PTR_ERR(child); 5206b9c7ed8SChristoph Hellwig goto out; 5216b9c7ed8SChristoph Hellwig } 522481bed45SChristoph Hellwig 523481bed45SChristoph Hellwig if (request == PTRACE_ATTACH) { 524481bed45SChristoph Hellwig ret = ptrace_attach(child); 525005f18dfSChristoph Hellwig goto out_put_task_struct; 526481bed45SChristoph Hellwig } 527481bed45SChristoph Hellwig 528481bed45SChristoph Hellwig ret = ptrace_check_attach(child, request == PTRACE_KILL); 529481bed45SChristoph Hellwig if (ret < 0) 530481bed45SChristoph Hellwig goto out_put_task_struct; 531481bed45SChristoph Hellwig 532481bed45SChristoph Hellwig ret = arch_ptrace(child, request, addr, data); 533481bed45SChristoph Hellwig if (ret < 0) 534481bed45SChristoph Hellwig goto out_put_task_struct; 535481bed45SChristoph Hellwig 536481bed45SChristoph Hellwig out_put_task_struct: 537481bed45SChristoph Hellwig put_task_struct(child); 538481bed45SChristoph Hellwig out: 539481bed45SChristoph Hellwig unlock_kernel(); 540481bed45SChristoph Hellwig return ret; 541481bed45SChristoph Hellwig } 542481bed45SChristoph Hellwig #endif /* __ARCH_SYS_PTRACE */ 543