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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/x86_64/kernel/ptrace.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/x86_64/kernel/ptrace.c')
-rw-r--r--arch/x86_64/kernel/ptrace.c547
1 files changed, 547 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c
new file mode 100644
index 000000000000..0b7b101debdf
--- /dev/null
+++ b/arch/x86_64/kernel/ptrace.c
@@ -0,0 +1,547 @@
1/* ptrace.c */
2/* By Ross Biro 1/23/92 */
3/*
4 * Pentium III FXSR, SSE support
5 * Gareth Hughes <gareth@valinux.com>, May 2000
6 *
7 * x86-64 port 2000-2002 Andi Kleen
8 */
9
10#include <linux/kernel.h>
11#include <linux/sched.h>
12#include <linux/mm.h>
13#include <linux/smp.h>
14#include <linux/smp_lock.h>
15#include <linux/errno.h>
16#include <linux/ptrace.h>
17#include <linux/user.h>
18#include <linux/security.h>
19#include <linux/audit.h>
20#include <linux/seccomp.h>
21
22#include <asm/uaccess.h>
23#include <asm/pgtable.h>
24#include <asm/system.h>
25#include <asm/processor.h>
26#include <asm/i387.h>
27#include <asm/debugreg.h>
28#include <asm/ldt.h>
29#include <asm/desc.h>
30#include <asm/proto.h>
31#include <asm/ia32.h>
32
33/*
34 * does not yet catch signals sent when the child dies.
35 * in exit.c or in signal.c.
36 */
37
38/* determines which flags the user has access to. */
39/* 1 = access 0 = no access */
40#define FLAG_MASK 0x44dd5UL
41
42/* set's the trap flag. */
43#define TRAP_FLAG 0x100UL
44
45/*
46 * eflags and offset of eflags on child stack..
47 */
48#define EFLAGS offsetof(struct pt_regs, eflags)
49#define EFL_OFFSET ((int)(EFLAGS-sizeof(struct pt_regs)))
50
51/*
52 * this routine will get a word off of the processes privileged stack.
53 * the offset is how far from the base addr as stored in the TSS.
54 * this routine assumes that all the privileged stacks are in our
55 * data space.
56 */
57static inline unsigned long get_stack_long(struct task_struct *task, int offset)
58{
59 unsigned char *stack;
60
61 stack = (unsigned char *)task->thread.rsp0;
62 stack += offset;
63 return (*((unsigned long *)stack));
64}
65
66/*
67 * this routine will put a word on the processes privileged stack.
68 * the offset is how far from the base addr as stored in the TSS.
69 * this routine assumes that all the privileged stacks are in our
70 * data space.
71 */
72static inline long put_stack_long(struct task_struct *task, int offset,
73 unsigned long data)
74{
75 unsigned char * stack;
76
77 stack = (unsigned char *) task->thread.rsp0;
78 stack += offset;
79 *(unsigned long *) stack = data;
80 return 0;
81}
82
83/*
84 * Called by kernel/ptrace.c when detaching..
85 *
86 * Make sure the single step bit is not set.
87 */
88void ptrace_disable(struct task_struct *child)
89{
90 long tmp;
91
92 clear_tsk_thread_flag(child, TIF_SINGLESTEP);
93 tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
94 put_stack_long(child, EFL_OFFSET, tmp);
95}
96
97static int putreg(struct task_struct *child,
98 unsigned long regno, unsigned long value)
99{
100 unsigned long tmp;
101
102 /* Some code in the 64bit emulation may not be 64bit clean.
103 Don't take any chances. */
104 if (test_tsk_thread_flag(child, TIF_IA32))
105 value &= 0xffffffff;
106 switch (regno) {
107 case offsetof(struct user_regs_struct,fs):
108 if (value && (value & 3) != 3)
109 return -EIO;
110 child->thread.fsindex = value & 0xffff;
111 return 0;
112 case offsetof(struct user_regs_struct,gs):
113 if (value && (value & 3) != 3)
114 return -EIO;
115 child->thread.gsindex = value & 0xffff;
116 return 0;
117 case offsetof(struct user_regs_struct,ds):
118 if (value && (value & 3) != 3)
119 return -EIO;
120 child->thread.ds = value & 0xffff;
121 return 0;
122 case offsetof(struct user_regs_struct,es):
123 if (value && (value & 3) != 3)
124 return -EIO;
125 child->thread.es = value & 0xffff;
126 return 0;
127 case offsetof(struct user_regs_struct,ss):
128 if ((value & 3) != 3)
129 return -EIO;
130 value &= 0xffff;
131 return 0;
132 case offsetof(struct user_regs_struct,fs_base):
133 if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
134 return -EIO;
135 child->thread.fs = value;
136 return 0;
137 case offsetof(struct user_regs_struct,gs_base):
138 if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
139 return -EIO;
140 child->thread.gs = value;
141 return 0;
142 case offsetof(struct user_regs_struct, eflags):
143 value &= FLAG_MASK;
144 tmp = get_stack_long(child, EFL_OFFSET);
145 tmp &= ~FLAG_MASK;
146 value |= tmp;
147 break;
148 case offsetof(struct user_regs_struct,cs):
149 if ((value & 3) != 3)
150 return -EIO;
151 value &= 0xffff;
152 break;
153 }
154 put_stack_long(child, regno - sizeof(struct pt_regs), value);
155 return 0;
156}
157
158static unsigned long getreg(struct task_struct *child, unsigned long regno)
159{
160 unsigned long val;
161 switch (regno) {
162 case offsetof(struct user_regs_struct, fs):
163 return child->thread.fsindex;
164 case offsetof(struct user_regs_struct, gs):
165 return child->thread.gsindex;
166 case offsetof(struct user_regs_struct, ds):
167 return child->thread.ds;
168 case offsetof(struct user_regs_struct, es):
169 return child->thread.es;
170 case offsetof(struct user_regs_struct, fs_base):
171 return child->thread.fs;
172 case offsetof(struct user_regs_struct, gs_base):
173 return child->thread.gs;
174 default:
175 regno = regno - sizeof(struct pt_regs);
176 val = get_stack_long(child, regno);
177 if (test_tsk_thread_flag(child, TIF_IA32))
178 val &= 0xffffffff;
179 return val;
180 }
181
182}
183
184asmlinkage long sys_ptrace(long request, long pid, unsigned long addr, long data)
185{
186 struct task_struct *child;
187 long i, ret;
188 unsigned ui;
189
190 /* This lock_kernel fixes a subtle race with suid exec */
191 lock_kernel();
192 ret = -EPERM;
193 if (request == PTRACE_TRACEME) {
194 /* are we already being traced? */
195 if (current->ptrace & PT_PTRACED)
196 goto out;
197 ret = security_ptrace(current->parent, current);
198 if (ret)
199 goto out;
200 /* set the ptrace bit in the process flags. */
201 current->ptrace |= PT_PTRACED;
202 ret = 0;
203 goto out;
204 }
205 ret = -ESRCH;
206 read_lock(&tasklist_lock);
207 child = find_task_by_pid(pid);
208 if (child)
209 get_task_struct(child);
210 read_unlock(&tasklist_lock);
211 if (!child)
212 goto out;
213
214 ret = -EPERM;
215 if (pid == 1) /* you may not mess with init */
216 goto out_tsk;
217
218 if (request == PTRACE_ATTACH) {
219 ret = ptrace_attach(child);
220 goto out_tsk;
221 }
222 ret = ptrace_check_attach(child, request == PTRACE_KILL);
223 if (ret < 0)
224 goto out_tsk;
225
226 switch (request) {
227 /* when I and D space are separate, these will need to be fixed. */
228 case PTRACE_PEEKTEXT: /* read word at location addr. */
229 case PTRACE_PEEKDATA: {
230 unsigned long tmp;
231 int copied;
232
233 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
234 ret = -EIO;
235 if (copied != sizeof(tmp))
236 break;
237 ret = put_user(tmp,(unsigned long __user *) data);
238 break;
239 }
240
241 /* read the word at location addr in the USER area. */
242 case PTRACE_PEEKUSR: {
243 unsigned long tmp;
244
245 ret = -EIO;
246 if ((addr & 7) ||
247 addr > sizeof(struct user) - 7)
248 break;
249
250 switch (addr) {
251 case 0 ... sizeof(struct user_regs_struct):
252 tmp = getreg(child, addr);
253 break;
254 case offsetof(struct user, u_debugreg[0]):
255 tmp = child->thread.debugreg0;
256 break;
257 case offsetof(struct user, u_debugreg[1]):
258 tmp = child->thread.debugreg1;
259 break;
260 case offsetof(struct user, u_debugreg[2]):
261 tmp = child->thread.debugreg2;
262 break;
263 case offsetof(struct user, u_debugreg[3]):
264 tmp = child->thread.debugreg3;
265 break;
266 case offsetof(struct user, u_debugreg[6]):
267 tmp = child->thread.debugreg6;
268 break;
269 case offsetof(struct user, u_debugreg[7]):
270 tmp = child->thread.debugreg7;
271 break;
272 default:
273 tmp = 0;
274 break;
275 }
276 ret = put_user(tmp,(unsigned long __user *) data);
277 break;
278 }
279
280 /* when I and D space are separate, this will have to be fixed. */
281 case PTRACE_POKETEXT: /* write the word at location addr. */
282 case PTRACE_POKEDATA:
283 ret = 0;
284 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
285 break;
286 ret = -EIO;
287 break;
288
289 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
290 ret = -EIO;
291 if ((addr & 7) ||
292 addr > sizeof(struct user) - 7)
293 break;
294
295 switch (addr) {
296 case 0 ... sizeof(struct user_regs_struct):
297 ret = putreg(child, addr, data);
298 break;
299 /* Disallows to set a breakpoint into the vsyscall */
300 case offsetof(struct user, u_debugreg[0]):
301 if (data >= TASK_SIZE-7) break;
302 child->thread.debugreg0 = data;
303 ret = 0;
304 break;
305 case offsetof(struct user, u_debugreg[1]):
306 if (data >= TASK_SIZE-7) break;
307 child->thread.debugreg1 = data;
308 ret = 0;
309 break;
310 case offsetof(struct user, u_debugreg[2]):
311 if (data >= TASK_SIZE-7) break;
312 child->thread.debugreg2 = data;
313 ret = 0;
314 break;
315 case offsetof(struct user, u_debugreg[3]):
316 if (data >= TASK_SIZE-7) break;
317 child->thread.debugreg3 = data;
318 ret = 0;
319 break;
320 case offsetof(struct user, u_debugreg[6]):
321 if (data >> 32)
322 break;
323 child->thread.debugreg6 = data;
324 ret = 0;
325 break;
326 case offsetof(struct user, u_debugreg[7]):
327 /* See arch/i386/kernel/ptrace.c for an explanation of
328 * this awkward check.*/
329 data &= ~DR_CONTROL_RESERVED;
330 for(i=0; i<4; i++)
331 if ((0x5454 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
332 break;
333 if (i == 4) {
334 child->thread.debugreg7 = data;
335 ret = 0;
336 }
337 break;
338 }
339 break;
340 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
341 case PTRACE_CONT: { /* restart after signal. */
342 long tmp;
343
344 ret = -EIO;
345 if ((unsigned long) data > _NSIG)
346 break;
347 if (request == PTRACE_SYSCALL)
348 set_tsk_thread_flag(child,TIF_SYSCALL_TRACE);
349 else
350 clear_tsk_thread_flag(child,TIF_SYSCALL_TRACE);
351 clear_tsk_thread_flag(child, TIF_SINGLESTEP);
352 child->exit_code = data;
353 /* make sure the single step bit is not set. */
354 tmp = get_stack_long(child, EFL_OFFSET);
355 tmp &= ~TRAP_FLAG;
356 put_stack_long(child, EFL_OFFSET,tmp);
357 wake_up_process(child);
358 ret = 0;
359 break;
360 }
361
362#ifdef CONFIG_IA32_EMULATION
363 /* This makes only sense with 32bit programs. Allow a
364 64bit debugger to fully examine them too. Better
365 don't use it against 64bit processes, use
366 PTRACE_ARCH_PRCTL instead. */
367 case PTRACE_SET_THREAD_AREA: {
368 struct user_desc __user *p;
369 int old;
370 p = (struct user_desc __user *)data;
371 get_user(old, &p->entry_number);
372 put_user(addr, &p->entry_number);
373 ret = do_set_thread_area(&child->thread, p);
374 put_user(old, &p->entry_number);
375 break;
376 case PTRACE_GET_THREAD_AREA:
377 p = (struct user_desc __user *)data;
378 get_user(old, &p->entry_number);
379 put_user(addr, &p->entry_number);
380 ret = do_get_thread_area(&child->thread, p);
381 put_user(old, &p->entry_number);
382 break;
383 }
384#endif
385 /* normal 64bit interface to access TLS data.
386 Works just like arch_prctl, except that the arguments
387 are reversed. */
388 case PTRACE_ARCH_PRCTL:
389 ret = do_arch_prctl(child, data, addr);
390 break;
391
392/*
393 * make the child exit. Best I can do is send it a sigkill.
394 * perhaps it should be put in the status that it wants to
395 * exit.
396 */
397 case PTRACE_KILL: {
398 long tmp;
399
400 ret = 0;
401 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
402 break;
403 clear_tsk_thread_flag(child, TIF_SINGLESTEP);
404 child->exit_code = SIGKILL;
405 /* make sure the single step bit is not set. */
406 tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
407 put_stack_long(child, EFL_OFFSET, tmp);
408 wake_up_process(child);
409 break;
410 }
411
412 case PTRACE_SINGLESTEP: { /* set the trap flag. */
413 long tmp;
414
415 ret = -EIO;
416 if ((unsigned long) data > _NSIG)
417 break;
418 clear_tsk_thread_flag(child,TIF_SYSCALL_TRACE);
419 if ((child->ptrace & PT_DTRACE) == 0) {
420 /* Spurious delayed TF traps may occur */
421 child->ptrace |= PT_DTRACE;
422 }
423 tmp = get_stack_long(child, EFL_OFFSET) | TRAP_FLAG;
424 put_stack_long(child, EFL_OFFSET, tmp);
425 set_tsk_thread_flag(child, TIF_SINGLESTEP);
426 child->exit_code = data;
427 /* give it a chance to run. */
428 wake_up_process(child);
429 ret = 0;
430 break;
431 }
432
433 case PTRACE_DETACH:
434 /* detach a process that was attached. */
435 ret = ptrace_detach(child, data);
436 break;
437
438 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
439 if (!access_ok(VERIFY_WRITE, (unsigned __user *)data,
440 sizeof(struct user_regs_struct))) {
441 ret = -EIO;
442 break;
443 }
444 ret = 0;
445 for (ui = 0; ui < sizeof(struct user_regs_struct); ui += sizeof(long)) {
446 ret |= __put_user(getreg(child, ui),(unsigned long __user *) data);
447 data += sizeof(long);
448 }
449 break;
450 }
451
452 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
453 unsigned long tmp;
454 if (!access_ok(VERIFY_READ, (unsigned __user *)data,
455 sizeof(struct user_regs_struct))) {
456 ret = -EIO;
457 break;
458 }
459 ret = 0;
460 for (ui = 0; ui < sizeof(struct user_regs_struct); ui += sizeof(long)) {
461 ret |= __get_user(tmp, (unsigned long __user *) data);
462 putreg(child, ui, tmp);
463 data += sizeof(long);
464 }
465 break;
466 }
467
468 case PTRACE_GETFPREGS: { /* Get the child extended FPU state. */
469 if (!access_ok(VERIFY_WRITE, (unsigned __user *)data,
470 sizeof(struct user_i387_struct))) {
471 ret = -EIO;
472 break;
473 }
474 ret = get_fpregs((struct user_i387_struct __user *)data, child);
475 break;
476 }
477
478 case PTRACE_SETFPREGS: { /* Set the child extended FPU state. */
479 if (!access_ok(VERIFY_READ, (unsigned __user *)data,
480 sizeof(struct user_i387_struct))) {
481 ret = -EIO;
482 break;
483 }
484 set_stopped_child_used_math(child);
485 ret = set_fpregs(child, (struct user_i387_struct __user *)data);
486 break;
487 }
488
489 default:
490 ret = ptrace_request(child, request, addr, data);
491 break;
492 }
493out_tsk:
494 put_task_struct(child);
495out:
496 unlock_kernel();
497 return ret;
498}
499
500static void syscall_trace(struct pt_regs *regs)
501{
502
503#if 0
504 printk("trace %s rip %lx rsp %lx rax %d origrax %d caller %lx tiflags %x ptrace %x\n",
505 current->comm,
506 regs->rip, regs->rsp, regs->rax, regs->orig_rax, __builtin_return_address(0),
507 current_thread_info()->flags, current->ptrace);
508#endif
509
510 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
511 ? 0x80 : 0));
512 /*
513 * this isn't the same as continuing with a signal, but it will do
514 * for normal use. strace only continues with a signal if the
515 * stopping signal is not SIGTRAP. -brl
516 */
517 if (current->exit_code) {
518 send_sig(current->exit_code, current, 1);
519 current->exit_code = 0;
520 }
521}
522
523asmlinkage void syscall_trace_enter(struct pt_regs *regs)
524{
525 /* do the secure computing check first */
526 secure_computing(regs->orig_rax);
527
528 if (unlikely(current->audit_context))
529 audit_syscall_entry(current, regs->orig_rax,
530 regs->rdi, regs->rsi,
531 regs->rdx, regs->r10);
532
533 if (test_thread_flag(TIF_SYSCALL_TRACE)
534 && (current->ptrace & PT_PTRACED))
535 syscall_trace(regs);
536}
537
538asmlinkage void syscall_trace_leave(struct pt_regs *regs)
539{
540 if (unlikely(current->audit_context))
541 audit_syscall_exit(current, regs->rax);
542
543 if ((test_thread_flag(TIF_SYSCALL_TRACE)
544 || test_thread_flag(TIF_SINGLESTEP))
545 && (current->ptrace & PT_PTRACED))
546 syscall_trace(regs);
547}
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