Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/ptrace.c |
| 3 | * |
| 4 | * (C) Copyright 1999 Linus Torvalds |
| 5 | * |
| 6 | * Common interfaces for "ptrace()" which we do not want |
| 7 | * to continually duplicate across every architecture. |
| 8 | */ |
| 9 | |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 10 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | #include <linux/module.h> |
| 12 | #include <linux/sched.h> |
| 13 | #include <linux/errno.h> |
| 14 | #include <linux/mm.h> |
| 15 | #include <linux/highmem.h> |
| 16 | #include <linux/pagemap.h> |
| 17 | #include <linux/smp_lock.h> |
| 18 | #include <linux/ptrace.h> |
| 19 | #include <linux/security.h> |
Jesper Juhl | 7ed20e1 | 2005-05-01 08:59:14 -0700 | [diff] [blame] | 20 | #include <linux/signal.h> |
Al Viro | a5cb013 | 2007-03-20 13:58:35 -0400 | [diff] [blame] | 21 | #include <linux/audit.h> |
Pavel Emelyanov | b488893 | 2007-10-18 23:40:14 -0700 | [diff] [blame] | 22 | #include <linux/pid_namespace.h> |
Adrian Bunk | f17d30a | 2008-02-06 01:36:44 -0800 | [diff] [blame] | 23 | #include <linux/syscalls.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | |
| 25 | #include <asm/pgtable.h> |
| 26 | #include <asm/uaccess.h> |
| 27 | |
| 28 | /* |
| 29 | * ptrace a task: make the debugger its new parent and |
| 30 | * move it to the ptrace list. |
| 31 | * |
| 32 | * Must be called with the tasklist lock write-held. |
| 33 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 34 | void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | { |
Eric Sesterhenn | 524223c | 2006-04-02 13:43:40 +0200 | [diff] [blame] | 36 | BUG_ON(!list_empty(&child->ptrace_list)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | if (child->parent == new_parent) |
| 38 | return; |
| 39 | list_add(&child->ptrace_list, &child->parent->ptrace_children); |
Oleg Nesterov | 9b678ec | 2006-03-28 16:11:05 -0800 | [diff] [blame] | 40 | remove_parent(child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | child->parent = new_parent; |
Oleg Nesterov | 9b678ec | 2006-03-28 16:11:05 -0800 | [diff] [blame] | 42 | add_parent(child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | } |
| 44 | |
| 45 | /* |
| 46 | * Turn a tracing stop into a normal stop now, since with no tracer there |
| 47 | * would be no way to wake it up with SIGCONT or SIGKILL. If there was a |
| 48 | * signal sent that would resume the child, but didn't because it was in |
| 49 | * TASK_TRACED, resume it now. |
| 50 | * Requires that irqs be disabled. |
| 51 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 52 | void ptrace_untrace(struct task_struct *child) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | { |
| 54 | spin_lock(&child->sighand->siglock); |
Matthew Wilcox | 6618a3e | 2007-12-06 11:06:16 -0500 | [diff] [blame] | 55 | if (task_is_traced(child)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 56 | if (child->signal->flags & SIGNAL_STOP_STOPPED) { |
Oleg Nesterov | d9ae90a | 2008-02-06 01:36:13 -0800 | [diff] [blame] | 57 | __set_task_state(child, TASK_STOPPED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | } else { |
| 59 | signal_wake_up(child, 1); |
| 60 | } |
| 61 | } |
| 62 | spin_unlock(&child->sighand->siglock); |
| 63 | } |
| 64 | |
| 65 | /* |
| 66 | * unptrace a task: move it back to its original parent and |
| 67 | * remove it from the ptrace list. |
| 68 | * |
| 69 | * Must be called with the tasklist lock write-held. |
| 70 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 71 | void __ptrace_unlink(struct task_struct *child) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | { |
Oleg Nesterov | 5ecfbae | 2006-02-15 22:50:10 +0300 | [diff] [blame] | 73 | BUG_ON(!child->ptrace); |
| 74 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | child->ptrace = 0; |
| 76 | if (!list_empty(&child->ptrace_list)) { |
| 77 | list_del_init(&child->ptrace_list); |
Oleg Nesterov | 9b678ec | 2006-03-28 16:11:05 -0800 | [diff] [blame] | 78 | remove_parent(child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | child->parent = child->real_parent; |
Oleg Nesterov | 9b678ec | 2006-03-28 16:11:05 -0800 | [diff] [blame] | 80 | add_parent(child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | } |
| 82 | |
Matthew Wilcox | 6618a3e | 2007-12-06 11:06:16 -0500 | [diff] [blame] | 83 | if (task_is_traced(child)) |
Roland McGrath | e57a505 | 2006-04-12 16:30:20 -0700 | [diff] [blame] | 84 | ptrace_untrace(child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | } |
| 86 | |
| 87 | /* |
| 88 | * Check that we have indeed attached to the thing.. |
| 89 | */ |
| 90 | int ptrace_check_attach(struct task_struct *child, int kill) |
| 91 | { |
| 92 | int ret = -ESRCH; |
| 93 | |
| 94 | /* |
| 95 | * We take the read lock around doing both checks to close a |
| 96 | * possible race where someone else was tracing our child and |
| 97 | * detached between these two checks. After this locked check, |
| 98 | * we are sure that this is our traced child and that can only |
| 99 | * be changed by us so it's not changing right after this. |
| 100 | */ |
| 101 | read_lock(&tasklist_lock); |
Oleg Nesterov | c0c0b64 | 2008-02-08 04:19:00 -0800 | [diff] [blame] | 102 | if ((child->ptrace & PT_PTRACED) && child->parent == current) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | ret = 0; |
Oleg Nesterov | c0c0b64 | 2008-02-08 04:19:00 -0800 | [diff] [blame] | 104 | /* |
| 105 | * child->sighand can't be NULL, release_task() |
| 106 | * does ptrace_unlink() before __exit_signal(). |
| 107 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | spin_lock_irq(&child->sighand->siglock); |
Oleg Nesterov | d9ae90a | 2008-02-06 01:36:13 -0800 | [diff] [blame] | 109 | if (task_is_stopped(child)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | child->state = TASK_TRACED; |
Oleg Nesterov | d9ae90a | 2008-02-06 01:36:13 -0800 | [diff] [blame] | 111 | else if (!task_is_traced(child) && !kill) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | ret = -ESRCH; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | spin_unlock_irq(&child->sighand->siglock); |
| 114 | } |
| 115 | read_unlock(&tasklist_lock); |
| 116 | |
Oleg Nesterov | d9ae90a | 2008-02-06 01:36:13 -0800 | [diff] [blame] | 117 | if (!ret && !kill) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | wait_task_inactive(child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 119 | |
| 120 | /* All systems go.. */ |
| 121 | return ret; |
| 122 | } |
| 123 | |
Al Viro | 831830b | 2008-01-02 14:09:57 +0000 | [diff] [blame] | 124 | int __ptrace_may_attach(struct task_struct *task) |
Miklos Szeredi | ab8d11b | 2005-09-06 15:18:24 -0700 | [diff] [blame] | 125 | { |
Eric W. Biederman | df26c40 | 2006-06-26 00:25:59 -0700 | [diff] [blame] | 126 | /* May we inspect the given task? |
| 127 | * This check is used both for attaching with ptrace |
| 128 | * and for allowing access to sensitive information in /proc. |
| 129 | * |
| 130 | * ptrace_attach denies several cases that /proc allows |
| 131 | * because setting up the necessary parent/child relationship |
| 132 | * or halting the specified task is impossible. |
| 133 | */ |
| 134 | int dumpable = 0; |
| 135 | /* Don't let security modules deny introspection */ |
| 136 | if (task == current) |
| 137 | return 0; |
Miklos Szeredi | ab8d11b | 2005-09-06 15:18:24 -0700 | [diff] [blame] | 138 | if (((current->uid != task->euid) || |
| 139 | (current->uid != task->suid) || |
| 140 | (current->uid != task->uid) || |
| 141 | (current->gid != task->egid) || |
| 142 | (current->gid != task->sgid) || |
| 143 | (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE)) |
| 144 | return -EPERM; |
| 145 | smp_rmb(); |
Eric W. Biederman | df26c40 | 2006-06-26 00:25:59 -0700 | [diff] [blame] | 146 | if (task->mm) |
Kawai, Hidehiro | 6c5d523 | 2007-07-19 01:48:27 -0700 | [diff] [blame] | 147 | dumpable = get_dumpable(task->mm); |
Eric W. Biederman | df26c40 | 2006-06-26 00:25:59 -0700 | [diff] [blame] | 148 | if (!dumpable && !capable(CAP_SYS_PTRACE)) |
Miklos Szeredi | ab8d11b | 2005-09-06 15:18:24 -0700 | [diff] [blame] | 149 | return -EPERM; |
| 150 | |
| 151 | return security_ptrace(current, task); |
| 152 | } |
| 153 | |
| 154 | int ptrace_may_attach(struct task_struct *task) |
| 155 | { |
| 156 | int err; |
| 157 | task_lock(task); |
Al Viro | 831830b | 2008-01-02 14:09:57 +0000 | [diff] [blame] | 158 | err = __ptrace_may_attach(task); |
Miklos Szeredi | ab8d11b | 2005-09-06 15:18:24 -0700 | [diff] [blame] | 159 | task_unlock(task); |
| 160 | return !err; |
| 161 | } |
| 162 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | int ptrace_attach(struct task_struct *task) |
| 164 | { |
| 165 | int retval; |
Sripathi Kodi | 6175ecf | 2007-07-15 23:39:26 -0700 | [diff] [blame] | 166 | unsigned long flags; |
Linus Torvalds | f5b40e3 | 2006-05-07 10:49:33 -0700 | [diff] [blame] | 167 | |
Al Viro | a5cb013 | 2007-03-20 13:58:35 -0400 | [diff] [blame] | 168 | audit_ptrace(task); |
| 169 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | retval = -EPERM; |
| 171 | if (task->pid <= 1) |
Linus Torvalds | f5b40e3 | 2006-05-07 10:49:33 -0700 | [diff] [blame] | 172 | goto out; |
Pavel Emelyanov | bac0abd | 2007-10-18 23:40:18 -0700 | [diff] [blame] | 173 | if (same_thread_group(task, current)) |
Linus Torvalds | f5b40e3 | 2006-05-07 10:49:33 -0700 | [diff] [blame] | 174 | goto out; |
| 175 | |
Linus Torvalds | f358166 | 2006-05-11 11:08:49 -0700 | [diff] [blame] | 176 | repeat: |
| 177 | /* |
| 178 | * Nasty, nasty. |
| 179 | * |
| 180 | * We want to hold both the task-lock and the |
| 181 | * tasklist_lock for writing at the same time. |
| 182 | * But that's against the rules (tasklist_lock |
| 183 | * is taken for reading by interrupts on other |
| 184 | * cpu's that may have task_lock). |
| 185 | */ |
Linus Torvalds | f5b40e3 | 2006-05-07 10:49:33 -0700 | [diff] [blame] | 186 | task_lock(task); |
Sripathi Kodi | 6175ecf | 2007-07-15 23:39:26 -0700 | [diff] [blame] | 187 | if (!write_trylock_irqsave(&tasklist_lock, flags)) { |
Linus Torvalds | f358166 | 2006-05-11 11:08:49 -0700 | [diff] [blame] | 188 | task_unlock(task); |
| 189 | do { |
| 190 | cpu_relax(); |
| 191 | } while (!write_can_lock(&tasklist_lock)); |
| 192 | goto repeat; |
| 193 | } |
Linus Torvalds | f5b40e3 | 2006-05-07 10:49:33 -0700 | [diff] [blame] | 194 | |
Eric W. Biederman | df26c40 | 2006-06-26 00:25:59 -0700 | [diff] [blame] | 195 | if (!task->mm) |
| 196 | goto bad; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | /* the same process cannot be attached many times */ |
| 198 | if (task->ptrace & PT_PTRACED) |
| 199 | goto bad; |
Linus Torvalds | b8c9a18 | 2008-01-02 13:48:27 -0800 | [diff] [blame] | 200 | retval = __ptrace_may_attach(task); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | if (retval) |
| 202 | goto bad; |
| 203 | |
| 204 | /* Go */ |
Oleg Nesterov | 6b39c7b | 2008-02-08 04:18:58 -0800 | [diff] [blame] | 205 | task->ptrace |= PT_PTRACED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | if (capable(CAP_SYS_PTRACE)) |
| 207 | task->ptrace |= PT_PTRACE_CAP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | __ptrace_link(task, current); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | |
| 211 | force_sig_specific(SIGSTOP, task); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | |
| 213 | bad: |
Sripathi Kodi | 6175ecf | 2007-07-15 23:39:26 -0700 | [diff] [blame] | 214 | write_unlock_irqrestore(&tasklist_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | task_unlock(task); |
Linus Torvalds | f5b40e3 | 2006-05-07 10:49:33 -0700 | [diff] [blame] | 216 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | return retval; |
| 218 | } |
| 219 | |
Oleg Nesterov | d5f70c0 | 2006-06-26 00:26:07 -0700 | [diff] [blame] | 220 | static inline void __ptrace_detach(struct task_struct *child, unsigned int data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | child->exit_code = data; |
Oleg Nesterov | 5ecfbae | 2006-02-15 22:50:10 +0300 | [diff] [blame] | 223 | /* .. re-parent .. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | __ptrace_unlink(child); |
| 225 | /* .. and wake it up. */ |
| 226 | if (child->exit_state != EXIT_ZOMBIE) |
| 227 | wake_up_process(child); |
Oleg Nesterov | 5ecfbae | 2006-02-15 22:50:10 +0300 | [diff] [blame] | 228 | } |
| 229 | |
| 230 | int ptrace_detach(struct task_struct *child, unsigned int data) |
| 231 | { |
| 232 | if (!valid_signal(data)) |
| 233 | return -EIO; |
| 234 | |
| 235 | /* Architecture-specific hardware disable .. */ |
| 236 | ptrace_disable(child); |
Roland McGrath | 7d94143 | 2007-09-05 03:05:56 -0700 | [diff] [blame] | 237 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
Oleg Nesterov | 5ecfbae | 2006-02-15 22:50:10 +0300 | [diff] [blame] | 238 | |
| 239 | write_lock_irq(&tasklist_lock); |
Oleg Nesterov | d5f70c0 | 2006-06-26 00:26:07 -0700 | [diff] [blame] | 240 | /* protect against de_thread()->release_task() */ |
Oleg Nesterov | 5ecfbae | 2006-02-15 22:50:10 +0300 | [diff] [blame] | 241 | if (child->ptrace) |
| 242 | __ptrace_detach(child, data); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | write_unlock_irq(&tasklist_lock); |
| 244 | |
| 245 | return 0; |
| 246 | } |
| 247 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) |
| 249 | { |
| 250 | int copied = 0; |
| 251 | |
| 252 | while (len > 0) { |
| 253 | char buf[128]; |
| 254 | int this_len, retval; |
| 255 | |
| 256 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len; |
| 257 | retval = access_process_vm(tsk, src, buf, this_len, 0); |
| 258 | if (!retval) { |
| 259 | if (copied) |
| 260 | break; |
| 261 | return -EIO; |
| 262 | } |
| 263 | if (copy_to_user(dst, buf, retval)) |
| 264 | return -EFAULT; |
| 265 | copied += retval; |
| 266 | src += retval; |
| 267 | dst += retval; |
| 268 | len -= retval; |
| 269 | } |
| 270 | return copied; |
| 271 | } |
| 272 | |
| 273 | int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) |
| 274 | { |
| 275 | int copied = 0; |
| 276 | |
| 277 | while (len > 0) { |
| 278 | char buf[128]; |
| 279 | int this_len, retval; |
| 280 | |
| 281 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len; |
| 282 | if (copy_from_user(buf, src, this_len)) |
| 283 | return -EFAULT; |
| 284 | retval = access_process_vm(tsk, dst, buf, this_len, 1); |
| 285 | if (!retval) { |
| 286 | if (copied) |
| 287 | break; |
| 288 | return -EIO; |
| 289 | } |
| 290 | copied += retval; |
| 291 | src += retval; |
| 292 | dst += retval; |
| 293 | len -= retval; |
| 294 | } |
| 295 | return copied; |
| 296 | } |
| 297 | |
| 298 | static int ptrace_setoptions(struct task_struct *child, long data) |
| 299 | { |
| 300 | child->ptrace &= ~PT_TRACE_MASK; |
| 301 | |
| 302 | if (data & PTRACE_O_TRACESYSGOOD) |
| 303 | child->ptrace |= PT_TRACESYSGOOD; |
| 304 | |
| 305 | if (data & PTRACE_O_TRACEFORK) |
| 306 | child->ptrace |= PT_TRACE_FORK; |
| 307 | |
| 308 | if (data & PTRACE_O_TRACEVFORK) |
| 309 | child->ptrace |= PT_TRACE_VFORK; |
| 310 | |
| 311 | if (data & PTRACE_O_TRACECLONE) |
| 312 | child->ptrace |= PT_TRACE_CLONE; |
| 313 | |
| 314 | if (data & PTRACE_O_TRACEEXEC) |
| 315 | child->ptrace |= PT_TRACE_EXEC; |
| 316 | |
| 317 | if (data & PTRACE_O_TRACEVFORKDONE) |
| 318 | child->ptrace |= PT_TRACE_VFORK_DONE; |
| 319 | |
| 320 | if (data & PTRACE_O_TRACEEXIT) |
| 321 | child->ptrace |= PT_TRACE_EXIT; |
| 322 | |
| 323 | return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; |
| 324 | } |
| 325 | |
| 326 | static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data) |
| 327 | { |
| 328 | siginfo_t lastinfo; |
| 329 | int error = -ESRCH; |
| 330 | |
| 331 | read_lock(&tasklist_lock); |
| 332 | if (likely(child->sighand != NULL)) { |
| 333 | error = -EINVAL; |
| 334 | spin_lock_irq(&child->sighand->siglock); |
| 335 | if (likely(child->last_siginfo != NULL)) { |
| 336 | lastinfo = *child->last_siginfo; |
| 337 | error = 0; |
| 338 | } |
| 339 | spin_unlock_irq(&child->sighand->siglock); |
| 340 | } |
| 341 | read_unlock(&tasklist_lock); |
| 342 | if (!error) |
| 343 | return copy_siginfo_to_user(data, &lastinfo); |
| 344 | return error; |
| 345 | } |
| 346 | |
| 347 | static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data) |
| 348 | { |
| 349 | siginfo_t newinfo; |
| 350 | int error = -ESRCH; |
| 351 | |
| 352 | if (copy_from_user(&newinfo, data, sizeof (siginfo_t))) |
| 353 | return -EFAULT; |
| 354 | |
| 355 | read_lock(&tasklist_lock); |
| 356 | if (likely(child->sighand != NULL)) { |
| 357 | error = -EINVAL; |
| 358 | spin_lock_irq(&child->sighand->siglock); |
| 359 | if (likely(child->last_siginfo != NULL)) { |
| 360 | *child->last_siginfo = newinfo; |
| 361 | error = 0; |
| 362 | } |
| 363 | spin_unlock_irq(&child->sighand->siglock); |
| 364 | } |
| 365 | read_unlock(&tasklist_lock); |
| 366 | return error; |
| 367 | } |
| 368 | |
Roland McGrath | 36df29d | 2008-01-30 13:30:51 +0100 | [diff] [blame] | 369 | |
| 370 | #ifdef PTRACE_SINGLESTEP |
| 371 | #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) |
| 372 | #else |
| 373 | #define is_singlestep(request) 0 |
| 374 | #endif |
| 375 | |
Roland McGrath | 5b88abb | 2008-01-30 13:30:53 +0100 | [diff] [blame] | 376 | #ifdef PTRACE_SINGLEBLOCK |
| 377 | #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) |
| 378 | #else |
| 379 | #define is_singleblock(request) 0 |
| 380 | #endif |
| 381 | |
Roland McGrath | 36df29d | 2008-01-30 13:30:51 +0100 | [diff] [blame] | 382 | #ifdef PTRACE_SYSEMU |
| 383 | #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) |
| 384 | #else |
| 385 | #define is_sysemu_singlestep(request) 0 |
| 386 | #endif |
| 387 | |
| 388 | static int ptrace_resume(struct task_struct *child, long request, long data) |
| 389 | { |
| 390 | if (!valid_signal(data)) |
| 391 | return -EIO; |
| 392 | |
| 393 | if (request == PTRACE_SYSCALL) |
| 394 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
| 395 | else |
| 396 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
| 397 | |
| 398 | #ifdef TIF_SYSCALL_EMU |
| 399 | if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) |
| 400 | set_tsk_thread_flag(child, TIF_SYSCALL_EMU); |
| 401 | else |
| 402 | clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); |
| 403 | #endif |
| 404 | |
Roland McGrath | 5b88abb | 2008-01-30 13:30:53 +0100 | [diff] [blame] | 405 | if (is_singleblock(request)) { |
| 406 | if (unlikely(!arch_has_block_step())) |
| 407 | return -EIO; |
| 408 | user_enable_block_step(child); |
| 409 | } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { |
Roland McGrath | 36df29d | 2008-01-30 13:30:51 +0100 | [diff] [blame] | 410 | if (unlikely(!arch_has_single_step())) |
| 411 | return -EIO; |
| 412 | user_enable_single_step(child); |
| 413 | } |
| 414 | else |
| 415 | user_disable_single_step(child); |
| 416 | |
| 417 | child->exit_code = data; |
| 418 | wake_up_process(child); |
| 419 | |
| 420 | return 0; |
| 421 | } |
| 422 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | int ptrace_request(struct task_struct *child, long request, |
| 424 | long addr, long data) |
| 425 | { |
| 426 | int ret = -EIO; |
| 427 | |
| 428 | switch (request) { |
Roland McGrath | 16c3e38 | 2008-01-30 13:31:47 +0100 | [diff] [blame] | 429 | case PTRACE_PEEKTEXT: |
| 430 | case PTRACE_PEEKDATA: |
| 431 | return generic_ptrace_peekdata(child, addr, data); |
| 432 | case PTRACE_POKETEXT: |
| 433 | case PTRACE_POKEDATA: |
| 434 | return generic_ptrace_pokedata(child, addr, data); |
| 435 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 436 | #ifdef PTRACE_OLDSETOPTIONS |
| 437 | case PTRACE_OLDSETOPTIONS: |
| 438 | #endif |
| 439 | case PTRACE_SETOPTIONS: |
| 440 | ret = ptrace_setoptions(child, data); |
| 441 | break; |
| 442 | case PTRACE_GETEVENTMSG: |
| 443 | ret = put_user(child->ptrace_message, (unsigned long __user *) data); |
| 444 | break; |
| 445 | case PTRACE_GETSIGINFO: |
| 446 | ret = ptrace_getsiginfo(child, (siginfo_t __user *) data); |
| 447 | break; |
| 448 | case PTRACE_SETSIGINFO: |
| 449 | ret = ptrace_setsiginfo(child, (siginfo_t __user *) data); |
| 450 | break; |
Alexey Dobriyan | 1bcf548 | 2007-10-16 01:23:45 -0700 | [diff] [blame] | 451 | case PTRACE_DETACH: /* detach a process that was attached. */ |
| 452 | ret = ptrace_detach(child, data); |
| 453 | break; |
Roland McGrath | 36df29d | 2008-01-30 13:30:51 +0100 | [diff] [blame] | 454 | |
| 455 | #ifdef PTRACE_SINGLESTEP |
| 456 | case PTRACE_SINGLESTEP: |
| 457 | #endif |
Roland McGrath | 5b88abb | 2008-01-30 13:30:53 +0100 | [diff] [blame] | 458 | #ifdef PTRACE_SINGLEBLOCK |
| 459 | case PTRACE_SINGLEBLOCK: |
| 460 | #endif |
Roland McGrath | 36df29d | 2008-01-30 13:30:51 +0100 | [diff] [blame] | 461 | #ifdef PTRACE_SYSEMU |
| 462 | case PTRACE_SYSEMU: |
| 463 | case PTRACE_SYSEMU_SINGLESTEP: |
| 464 | #endif |
| 465 | case PTRACE_SYSCALL: |
| 466 | case PTRACE_CONT: |
| 467 | return ptrace_resume(child, request, data); |
| 468 | |
| 469 | case PTRACE_KILL: |
| 470 | if (child->exit_state) /* already dead */ |
| 471 | return 0; |
| 472 | return ptrace_resume(child, request, SIGKILL); |
| 473 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | default: |
| 475 | break; |
| 476 | } |
| 477 | |
| 478 | return ret; |
| 479 | } |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 480 | |
Christoph Hellwig | 6b9c7ed8 | 2006-01-08 01:02:33 -0800 | [diff] [blame] | 481 | /** |
| 482 | * ptrace_traceme -- helper for PTRACE_TRACEME |
| 483 | * |
| 484 | * Performs checks and sets PT_PTRACED. |
| 485 | * Should be used by all ptrace implementations for PTRACE_TRACEME. |
| 486 | */ |
| 487 | int ptrace_traceme(void) |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 488 | { |
Linus Torvalds | f5b40e3 | 2006-05-07 10:49:33 -0700 | [diff] [blame] | 489 | int ret = -EPERM; |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 490 | |
| 491 | /* |
Christoph Hellwig | 6b9c7ed8 | 2006-01-08 01:02:33 -0800 | [diff] [blame] | 492 | * Are we already being traced? |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 493 | */ |
Linus Torvalds | f5b40e3 | 2006-05-07 10:49:33 -0700 | [diff] [blame] | 494 | task_lock(current); |
| 495 | if (!(current->ptrace & PT_PTRACED)) { |
| 496 | ret = security_ptrace(current->parent, current); |
| 497 | /* |
| 498 | * Set the ptrace bit in the process ptrace flags. |
| 499 | */ |
| 500 | if (!ret) |
| 501 | current->ptrace |= PT_PTRACED; |
| 502 | } |
| 503 | task_unlock(current); |
| 504 | return ret; |
Christoph Hellwig | 6b9c7ed8 | 2006-01-08 01:02:33 -0800 | [diff] [blame] | 505 | } |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 506 | |
Christoph Hellwig | 6b9c7ed8 | 2006-01-08 01:02:33 -0800 | [diff] [blame] | 507 | /** |
| 508 | * ptrace_get_task_struct -- grab a task struct reference for ptrace |
| 509 | * @pid: process id to grab a task_struct reference of |
| 510 | * |
| 511 | * This function is a helper for ptrace implementations. It checks |
| 512 | * permissions and then grabs a task struct for use of the actual |
| 513 | * ptrace implementation. |
| 514 | * |
| 515 | * Returns the task_struct for @pid or an ERR_PTR() on failure. |
| 516 | */ |
| 517 | struct task_struct *ptrace_get_task_struct(pid_t pid) |
| 518 | { |
| 519 | struct task_struct *child; |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 520 | |
| 521 | /* |
Christoph Hellwig | 6b9c7ed8 | 2006-01-08 01:02:33 -0800 | [diff] [blame] | 522 | * Tracing init is not allowed. |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 523 | */ |
| 524 | if (pid == 1) |
Christoph Hellwig | 6b9c7ed8 | 2006-01-08 01:02:33 -0800 | [diff] [blame] | 525 | return ERR_PTR(-EPERM); |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 526 | |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 527 | read_lock(&tasklist_lock); |
Pavel Emelyanov | 228ebcb | 2007-10-18 23:40:16 -0700 | [diff] [blame] | 528 | child = find_task_by_vpid(pid); |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 529 | if (child) |
| 530 | get_task_struct(child); |
Sukadev Bhattiprolu | f400e19 | 2006-09-29 02:00:07 -0700 | [diff] [blame] | 531 | |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 532 | read_unlock(&tasklist_lock); |
| 533 | if (!child) |
Christoph Hellwig | 6b9c7ed8 | 2006-01-08 01:02:33 -0800 | [diff] [blame] | 534 | return ERR_PTR(-ESRCH); |
| 535 | return child; |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 536 | } |
| 537 | |
Christoph Hellwig | 0ac1555 | 2007-10-16 01:26:37 -0700 | [diff] [blame] | 538 | #ifndef arch_ptrace_attach |
| 539 | #define arch_ptrace_attach(child) do { } while (0) |
| 540 | #endif |
| 541 | |
Christoph Hellwig | 6b9c7ed8 | 2006-01-08 01:02:33 -0800 | [diff] [blame] | 542 | #ifndef __ARCH_SYS_PTRACE |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 543 | asmlinkage long sys_ptrace(long request, long pid, long addr, long data) |
| 544 | { |
| 545 | struct task_struct *child; |
| 546 | long ret; |
| 547 | |
| 548 | /* |
| 549 | * This lock_kernel fixes a subtle race with suid exec |
| 550 | */ |
| 551 | lock_kernel(); |
Christoph Hellwig | 6b9c7ed8 | 2006-01-08 01:02:33 -0800 | [diff] [blame] | 552 | if (request == PTRACE_TRACEME) { |
| 553 | ret = ptrace_traceme(); |
Haavard Skinnemoen | 6ea6dd9 | 2007-11-27 13:02:40 +0100 | [diff] [blame] | 554 | if (!ret) |
| 555 | arch_ptrace_attach(current); |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 556 | goto out; |
Christoph Hellwig | 6b9c7ed8 | 2006-01-08 01:02:33 -0800 | [diff] [blame] | 557 | } |
| 558 | |
| 559 | child = ptrace_get_task_struct(pid); |
| 560 | if (IS_ERR(child)) { |
| 561 | ret = PTR_ERR(child); |
| 562 | goto out; |
| 563 | } |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 564 | |
| 565 | if (request == PTRACE_ATTACH) { |
| 566 | ret = ptrace_attach(child); |
Christoph Hellwig | 0ac1555 | 2007-10-16 01:26:37 -0700 | [diff] [blame] | 567 | /* |
| 568 | * Some architectures need to do book-keeping after |
| 569 | * a ptrace attach. |
| 570 | */ |
| 571 | if (!ret) |
| 572 | arch_ptrace_attach(child); |
Christoph Hellwig | 005f18d | 2005-11-13 16:06:33 -0800 | [diff] [blame] | 573 | goto out_put_task_struct; |
Christoph Hellwig | 481bed4 | 2005-11-07 00:59:47 -0800 | [diff] [blame] | 574 | } |
| 575 | |
| 576 | ret = ptrace_check_attach(child, request == PTRACE_KILL); |
| 577 | if (ret < 0) |
| 578 | goto out_put_task_struct; |
| 579 | |
| 580 | ret = arch_ptrace(child, request, addr, data); |
| 581 | if (ret < 0) |
| 582 | goto out_put_task_struct; |
| 583 | |
| 584 | out_put_task_struct: |
| 585 | put_task_struct(child); |
| 586 | out: |
| 587 | unlock_kernel(); |
| 588 | return ret; |
| 589 | } |
| 590 | #endif /* __ARCH_SYS_PTRACE */ |
Alexey Dobriyan | 7664732 | 2007-07-17 04:03:43 -0700 | [diff] [blame] | 591 | |
| 592 | int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data) |
| 593 | { |
| 594 | unsigned long tmp; |
| 595 | int copied; |
| 596 | |
| 597 | copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); |
| 598 | if (copied != sizeof(tmp)) |
| 599 | return -EIO; |
| 600 | return put_user(tmp, (unsigned long __user *)data); |
| 601 | } |
Alexey Dobriyan | f284ce7 | 2007-07-17 04:03:44 -0700 | [diff] [blame] | 602 | |
| 603 | int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data) |
| 604 | { |
| 605 | int copied; |
| 606 | |
| 607 | copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); |
| 608 | return (copied == sizeof(data)) ? 0 : -EIO; |
| 609 | } |
Roland McGrath | 032d82d | 2008-01-30 13:31:47 +0100 | [diff] [blame] | 610 | |
| 611 | #ifdef CONFIG_COMPAT |
| 612 | #include <linux/compat.h> |
| 613 | |
| 614 | int compat_ptrace_request(struct task_struct *child, compat_long_t request, |
| 615 | compat_ulong_t addr, compat_ulong_t data) |
| 616 | { |
| 617 | compat_ulong_t __user *datap = compat_ptr(data); |
| 618 | compat_ulong_t word; |
| 619 | int ret; |
| 620 | |
| 621 | switch (request) { |
| 622 | case PTRACE_PEEKTEXT: |
| 623 | case PTRACE_PEEKDATA: |
| 624 | ret = access_process_vm(child, addr, &word, sizeof(word), 0); |
| 625 | if (ret != sizeof(word)) |
| 626 | ret = -EIO; |
| 627 | else |
| 628 | ret = put_user(word, datap); |
| 629 | break; |
| 630 | |
| 631 | case PTRACE_POKETEXT: |
| 632 | case PTRACE_POKEDATA: |
| 633 | ret = access_process_vm(child, addr, &data, sizeof(data), 1); |
| 634 | ret = (ret != sizeof(data) ? -EIO : 0); |
| 635 | break; |
| 636 | |
| 637 | case PTRACE_GETEVENTMSG: |
| 638 | ret = put_user((compat_ulong_t) child->ptrace_message, datap); |
| 639 | break; |
| 640 | |
| 641 | default: |
| 642 | ret = ptrace_request(child, request, addr, data); |
| 643 | } |
| 644 | |
| 645 | return ret; |
| 646 | } |
Roland McGrath | c269f19 | 2008-01-30 13:31:48 +0100 | [diff] [blame] | 647 | |
| 648 | #ifdef __ARCH_WANT_COMPAT_SYS_PTRACE |
| 649 | asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, |
| 650 | compat_long_t addr, compat_long_t data) |
| 651 | { |
| 652 | struct task_struct *child; |
| 653 | long ret; |
| 654 | |
| 655 | /* |
| 656 | * This lock_kernel fixes a subtle race with suid exec |
| 657 | */ |
| 658 | lock_kernel(); |
| 659 | if (request == PTRACE_TRACEME) { |
| 660 | ret = ptrace_traceme(); |
| 661 | goto out; |
| 662 | } |
| 663 | |
| 664 | child = ptrace_get_task_struct(pid); |
| 665 | if (IS_ERR(child)) { |
| 666 | ret = PTR_ERR(child); |
| 667 | goto out; |
| 668 | } |
| 669 | |
| 670 | if (request == PTRACE_ATTACH) { |
| 671 | ret = ptrace_attach(child); |
| 672 | /* |
| 673 | * Some architectures need to do book-keeping after |
| 674 | * a ptrace attach. |
| 675 | */ |
| 676 | if (!ret) |
| 677 | arch_ptrace_attach(child); |
| 678 | goto out_put_task_struct; |
| 679 | } |
| 680 | |
| 681 | ret = ptrace_check_attach(child, request == PTRACE_KILL); |
| 682 | if (!ret) |
| 683 | ret = compat_arch_ptrace(child, request, addr, data); |
| 684 | |
| 685 | out_put_task_struct: |
| 686 | put_task_struct(child); |
| 687 | out: |
| 688 | unlock_kernel(); |
| 689 | return ret; |
| 690 | } |
| 691 | #endif /* __ARCH_WANT_COMPAT_SYS_PTRACE */ |
| 692 | |
Roland McGrath | 032d82d | 2008-01-30 13:31:47 +0100 | [diff] [blame] | 693 | #endif /* CONFIG_COMPAT */ |