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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - arch/x86_64/kernel/ptrace.c
2 /* By Ross Biro 1/23/92 */
4 * Pentium III FXSR, SSE support
5 * Gareth Hughes <gareth@valinux.com>, May 2000
7 * x86-64 port 2000-2002 Andi Kleen
10 #include <linux/kernel.h>
11 #include <linux/sched.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 #include <linux/signal.h>
23 #include <asm/uaccess.h>
24 #include <asm/pgtable.h>
25 #include <asm/system.h>
26 #include <asm/processor.h>
28 #include <asm/debugreg.h>
31 #include <asm/proto.h>
35 * does not yet catch signals sent when the child dies.
36 * in exit.c or in signal.c.
39 /* determines which flags the user has access to. */
40 /* 1 = access 0 = no access */
41 #define FLAG_MASK 0x44dd5UL
43 /* set's the trap flag. */
44 #define TRAP_FLAG 0x100UL
47 * eflags and offset of eflags on child stack..
49 #define EFLAGS offsetof(struct pt_regs, eflags)
50 #define EFL_OFFSET ((int)(EFLAGS-sizeof(struct pt_regs)))
53 * this routine will get a word off of the processes privileged stack.
54 * the offset is how far from the base addr as stored in the TSS.
55 * this routine assumes that all the privileged stacks are in our
58 static inline unsigned long get_stack_long(struct task_struct
*task
, int offset
)
62 stack
= (unsigned char *)task
->thread
.rsp0
;
64 return (*((unsigned long *)stack
));
67 static inline struct pt_regs
*get_child_regs(struct task_struct
*task
)
69 struct pt_regs
*regs
= (void *)task
->thread
.rsp0
;
74 * this routine will put a word on the processes privileged stack.
75 * the offset is how far from the base addr as stored in the TSS.
76 * this routine assumes that all the privileged stacks are in our
79 static inline long put_stack_long(struct task_struct
*task
, int offset
,
82 unsigned char * stack
;
84 stack
= (unsigned char *) task
->thread
.rsp0
;
86 *(unsigned long *) stack
= data
;
92 unsigned long convert_rip_to_linear(struct task_struct
*child
, struct pt_regs
*regs
)
94 unsigned long addr
, seg
;
97 seg
= regs
->cs
& 0xffff;
100 * We'll assume that the code segments in the GDT
101 * are all zero-based. That is largely true: the
102 * TLS segments are used for data, and the PNPBIOS
103 * and APM bios ones we just ignore here.
105 if (seg
& LDT_SEGMENT
) {
109 down(&child
->mm
->context
.sem
);
110 desc
= child
->mm
->context
.ldt
+ (seg
& ~7);
111 base
= (desc
[0] >> 16) | ((desc
[1] & 0xff) << 16) | (desc
[1] & 0xff000000);
113 /* 16-bit code segment? */
114 if (!((desc
[1] >> 22) & 1))
117 up(&child
->mm
->context
.sem
);
122 static int is_at_popf(struct task_struct
*child
, struct pt_regs
*regs
)
125 unsigned char opcode
[16];
126 unsigned long addr
= convert_rip_to_linear(child
, regs
);
128 copied
= access_process_vm(child
, addr
, opcode
, sizeof(opcode
), 0);
129 for (i
= 0; i
< copied
; i
++) {
137 /* opcode and address size prefixes */
138 case 0x66: case 0x67:
140 /* irrelevant prefixes (segment overrides and repeats) */
141 case 0x26: case 0x2e:
142 case 0x36: case 0x3e:
143 case 0x64: case 0x65:
144 case 0xf0: case 0xf2: case 0xf3:
151 /* CHECKME: f0, f2, f3 */
154 * pushf: NOTE! We should probably not let
155 * the user see the TF bit being set. But
156 * it's more pain than it's worth to avoid
157 * it, and a debugger could emulate this
158 * all in user space if it _really_ cares.
168 static void set_singlestep(struct task_struct
*child
)
170 struct pt_regs
*regs
= get_child_regs(child
);
173 * Always set TIF_SINGLESTEP - this guarantees that
174 * we single-step system calls etc.. This will also
175 * cause us to set TF when returning to user mode.
177 set_tsk_thread_flag(child
, TIF_SINGLESTEP
);
180 * If TF was already set, don't do anything else
182 if (regs
->eflags
& TRAP_FLAG
)
185 /* Set TF on the kernel stack.. */
186 regs
->eflags
|= TRAP_FLAG
;
189 * ..but if TF is changed by the instruction we will trace,
190 * don't mark it as being "us" that set it, so that we
191 * won't clear it by hand later.
193 * AK: this is not enough, LAHF and IRET can change TF in user space too.
195 if (is_at_popf(child
, regs
))
198 child
->ptrace
|= PT_DTRACE
;
201 static void clear_singlestep(struct task_struct
*child
)
203 /* Always clear TIF_SINGLESTEP... */
204 clear_tsk_thread_flag(child
, TIF_SINGLESTEP
);
206 /* But touch TF only if it was set by us.. */
207 if (child
->ptrace
& PT_DTRACE
) {
208 struct pt_regs
*regs
= get_child_regs(child
);
209 regs
->eflags
&= ~TRAP_FLAG
;
210 child
->ptrace
&= ~PT_DTRACE
;
215 * Called by kernel/ptrace.c when detaching..
217 * Make sure the single step bit is not set.
219 void ptrace_disable(struct task_struct
*child
)
221 clear_singlestep(child
);
224 static int putreg(struct task_struct
*child
,
225 unsigned long regno
, unsigned long value
)
229 /* Some code in the 64bit emulation may not be 64bit clean.
230 Don't take any chances. */
231 if (test_tsk_thread_flag(child
, TIF_IA32
))
234 case offsetof(struct user_regs_struct
,fs
):
235 if (value
&& (value
& 3) != 3)
237 child
->thread
.fsindex
= value
& 0xffff;
239 case offsetof(struct user_regs_struct
,gs
):
240 if (value
&& (value
& 3) != 3)
242 child
->thread
.gsindex
= value
& 0xffff;
244 case offsetof(struct user_regs_struct
,ds
):
245 if (value
&& (value
& 3) != 3)
247 child
->thread
.ds
= value
& 0xffff;
249 case offsetof(struct user_regs_struct
,es
):
250 if (value
&& (value
& 3) != 3)
252 child
->thread
.es
= value
& 0xffff;
254 case offsetof(struct user_regs_struct
,ss
):
255 if ((value
& 3) != 3)
259 case offsetof(struct user_regs_struct
,fs_base
):
260 if (value
>= TASK_SIZE_OF(child
))
262 child
->thread
.fs
= value
;
264 case offsetof(struct user_regs_struct
,gs_base
):
265 if (value
>= TASK_SIZE_OF(child
))
267 child
->thread
.gs
= value
;
269 case offsetof(struct user_regs_struct
, eflags
):
271 tmp
= get_stack_long(child
, EFL_OFFSET
);
275 case offsetof(struct user_regs_struct
,cs
):
276 if ((value
& 3) != 3)
280 case offsetof(struct user_regs_struct
, rip
):
281 /* Check if the new RIP address is canonical */
282 if (value
>= TASK_SIZE_OF(child
))
286 put_stack_long(child
, regno
- sizeof(struct pt_regs
), value
);
290 static unsigned long getreg(struct task_struct
*child
, unsigned long regno
)
294 case offsetof(struct user_regs_struct
, fs
):
295 return child
->thread
.fsindex
;
296 case offsetof(struct user_regs_struct
, gs
):
297 return child
->thread
.gsindex
;
298 case offsetof(struct user_regs_struct
, ds
):
299 return child
->thread
.ds
;
300 case offsetof(struct user_regs_struct
, es
):
301 return child
->thread
.es
;
302 case offsetof(struct user_regs_struct
, fs_base
):
303 return child
->thread
.fs
;
304 case offsetof(struct user_regs_struct
, gs_base
):
305 return child
->thread
.gs
;
307 regno
= regno
- sizeof(struct pt_regs
);
308 val
= get_stack_long(child
, regno
);
309 if (test_tsk_thread_flag(child
, TIF_IA32
))
316 asmlinkage
long sys_ptrace(long request
, long pid
, unsigned long addr
, long data
)
318 struct task_struct
*child
;
322 /* This lock_kernel fixes a subtle race with suid exec */
325 if (request
== PTRACE_TRACEME
) {
326 /* are we already being traced? */
327 if (current
->ptrace
& PT_PTRACED
)
329 ret
= security_ptrace(current
->parent
, current
);
332 /* set the ptrace bit in the process flags. */
333 current
->ptrace
|= PT_PTRACED
;
338 read_lock(&tasklist_lock
);
339 child
= find_task_by_pid(pid
);
341 get_task_struct(child
);
342 read_unlock(&tasklist_lock
);
347 if (pid
== 1) /* you may not mess with init */
350 if (request
== PTRACE_ATTACH
) {
351 ret
= ptrace_attach(child
);
354 ret
= ptrace_check_attach(child
, request
== PTRACE_KILL
);
359 /* when I and D space are separate, these will need to be fixed. */
360 case PTRACE_PEEKTEXT
: /* read word at location addr. */
361 case PTRACE_PEEKDATA
: {
365 copied
= access_process_vm(child
, addr
, &tmp
, sizeof(tmp
), 0);
367 if (copied
!= sizeof(tmp
))
369 ret
= put_user(tmp
,(unsigned long __user
*) data
);
373 /* read the word at location addr in the USER area. */
374 case PTRACE_PEEKUSR
: {
379 addr
> sizeof(struct user
) - 7)
383 case 0 ... sizeof(struct user_regs_struct
) - sizeof(long):
384 tmp
= getreg(child
, addr
);
386 case offsetof(struct user
, u_debugreg
[0]):
387 tmp
= child
->thread
.debugreg0
;
389 case offsetof(struct user
, u_debugreg
[1]):
390 tmp
= child
->thread
.debugreg1
;
392 case offsetof(struct user
, u_debugreg
[2]):
393 tmp
= child
->thread
.debugreg2
;
395 case offsetof(struct user
, u_debugreg
[3]):
396 tmp
= child
->thread
.debugreg3
;
398 case offsetof(struct user
, u_debugreg
[6]):
399 tmp
= child
->thread
.debugreg6
;
401 case offsetof(struct user
, u_debugreg
[7]):
402 tmp
= child
->thread
.debugreg7
;
408 ret
= put_user(tmp
,(unsigned long __user
*) data
);
412 /* when I and D space are separate, this will have to be fixed. */
413 case PTRACE_POKETEXT
: /* write the word at location addr. */
414 case PTRACE_POKEDATA
:
416 if (access_process_vm(child
, addr
, &data
, sizeof(data
), 1) == sizeof(data
))
421 case PTRACE_POKEUSR
: /* write the word at location addr in the USER area */
423 int dsize
= test_tsk_thread_flag(child
, TIF_IA32
) ? 3 : 7;
426 addr
> sizeof(struct user
) - 7)
430 case 0 ... sizeof(struct user_regs_struct
) - sizeof(long):
431 ret
= putreg(child
, addr
, data
);
433 /* Disallows to set a breakpoint into the vsyscall */
434 case offsetof(struct user
, u_debugreg
[0]):
435 if (data
>= TASK_SIZE_OF(child
) - dsize
) break;
436 child
->thread
.debugreg0
= data
;
439 case offsetof(struct user
, u_debugreg
[1]):
440 if (data
>= TASK_SIZE_OF(child
) - dsize
) break;
441 child
->thread
.debugreg1
= data
;
444 case offsetof(struct user
, u_debugreg
[2]):
445 if (data
>= TASK_SIZE_OF(child
) - dsize
) break;
446 child
->thread
.debugreg2
= data
;
449 case offsetof(struct user
, u_debugreg
[3]):
450 if (data
>= TASK_SIZE_OF(child
) - dsize
) break;
451 child
->thread
.debugreg3
= data
;
454 case offsetof(struct user
, u_debugreg
[6]):
457 child
->thread
.debugreg6
= data
;
460 case offsetof(struct user
, u_debugreg
[7]):
461 /* See arch/i386/kernel/ptrace.c for an explanation of
462 * this awkward check.*/
463 data
&= ~DR_CONTROL_RESERVED
;
465 if ((0x5454 >> ((data
>> (16 + 4*i
)) & 0xf)) & 1)
468 child
->thread
.debugreg7
= data
;
475 case PTRACE_SYSCALL
: /* continue and stop at next (return from) syscall */
476 case PTRACE_CONT
: /* restart after signal. */
479 if (!valid_signal(data
))
481 if (request
== PTRACE_SYSCALL
)
482 set_tsk_thread_flag(child
,TIF_SYSCALL_TRACE
);
484 clear_tsk_thread_flag(child
,TIF_SYSCALL_TRACE
);
485 clear_tsk_thread_flag(child
, TIF_SINGLESTEP
);
486 child
->exit_code
= data
;
487 /* make sure the single step bit is not set. */
488 clear_singlestep(child
);
489 wake_up_process(child
);
493 #ifdef CONFIG_IA32_EMULATION
494 /* This makes only sense with 32bit programs. Allow a
495 64bit debugger to fully examine them too. Better
496 don't use it against 64bit processes, use
497 PTRACE_ARCH_PRCTL instead. */
498 case PTRACE_SET_THREAD_AREA
: {
499 struct user_desc __user
*p
;
501 p
= (struct user_desc __user
*)data
;
502 get_user(old
, &p
->entry_number
);
503 put_user(addr
, &p
->entry_number
);
504 ret
= do_set_thread_area(&child
->thread
, p
);
505 put_user(old
, &p
->entry_number
);
507 case PTRACE_GET_THREAD_AREA
:
508 p
= (struct user_desc __user
*)data
;
509 get_user(old
, &p
->entry_number
);
510 put_user(addr
, &p
->entry_number
);
511 ret
= do_get_thread_area(&child
->thread
, p
);
512 put_user(old
, &p
->entry_number
);
516 /* normal 64bit interface to access TLS data.
517 Works just like arch_prctl, except that the arguments
519 case PTRACE_ARCH_PRCTL
:
520 ret
= do_arch_prctl(child
, data
, addr
);
524 * make the child exit. Best I can do is send it a sigkill.
525 * perhaps it should be put in the status that it wants to
530 if (child
->exit_state
== EXIT_ZOMBIE
) /* already dead */
532 clear_tsk_thread_flag(child
, TIF_SINGLESTEP
);
533 child
->exit_code
= SIGKILL
;
534 /* make sure the single step bit is not set. */
535 clear_singlestep(child
);
536 wake_up_process(child
);
539 case PTRACE_SINGLESTEP
: /* set the trap flag. */
541 if (!valid_signal(data
))
543 clear_tsk_thread_flag(child
,TIF_SYSCALL_TRACE
);
544 set_singlestep(child
);
545 child
->exit_code
= data
;
546 /* give it a chance to run. */
547 wake_up_process(child
);
552 /* detach a process that was attached. */
553 ret
= ptrace_detach(child
, data
);
556 case PTRACE_GETREGS
: { /* Get all gp regs from the child. */
557 if (!access_ok(VERIFY_WRITE
, (unsigned __user
*)data
,
558 sizeof(struct user_regs_struct
))) {
563 for (ui
= 0; ui
< sizeof(struct user_regs_struct
); ui
+= sizeof(long)) {
564 ret
|= __put_user(getreg(child
, ui
),(unsigned long __user
*) data
);
565 data
+= sizeof(long);
570 case PTRACE_SETREGS
: { /* Set all gp regs in the child. */
572 if (!access_ok(VERIFY_READ
, (unsigned __user
*)data
,
573 sizeof(struct user_regs_struct
))) {
578 for (ui
= 0; ui
< sizeof(struct user_regs_struct
); ui
+= sizeof(long)) {
579 ret
|= __get_user(tmp
, (unsigned long __user
*) data
);
580 putreg(child
, ui
, tmp
);
581 data
+= sizeof(long);
586 case PTRACE_GETFPREGS
: { /* Get the child extended FPU state. */
587 if (!access_ok(VERIFY_WRITE
, (unsigned __user
*)data
,
588 sizeof(struct user_i387_struct
))) {
592 ret
= get_fpregs((struct user_i387_struct __user
*)data
, child
);
596 case PTRACE_SETFPREGS
: { /* Set the child extended FPU state. */
597 if (!access_ok(VERIFY_READ
, (unsigned __user
*)data
,
598 sizeof(struct user_i387_struct
))) {
602 set_stopped_child_used_math(child
);
603 ret
= set_fpregs(child
, (struct user_i387_struct __user
*)data
);
608 ret
= ptrace_request(child
, request
, addr
, data
);
612 put_task_struct(child
);
618 static void syscall_trace(struct pt_regs
*regs
)
622 printk("trace %s rip %lx rsp %lx rax %d origrax %d caller %lx tiflags %x ptrace %x\n",
624 regs
->rip
, regs
->rsp
, regs
->rax
, regs
->orig_rax
, __builtin_return_address(0),
625 current_thread_info()->flags
, current
->ptrace
);
628 ptrace_notify(SIGTRAP
| ((current
->ptrace
& PT_TRACESYSGOOD
)
631 * this isn't the same as continuing with a signal, but it will do
632 * for normal use. strace only continues with a signal if the
633 * stopping signal is not SIGTRAP. -brl
635 if (current
->exit_code
) {
636 send_sig(current
->exit_code
, current
, 1);
637 current
->exit_code
= 0;
641 asmlinkage
void syscall_trace_enter(struct pt_regs
*regs
)
643 /* do the secure computing check first */
644 secure_computing(regs
->orig_rax
);
646 if (test_thread_flag(TIF_SYSCALL_TRACE
)
647 && (current
->ptrace
& PT_PTRACED
))
650 if (unlikely(current
->audit_context
)) {
651 if (test_thread_flag(TIF_IA32
)) {
652 audit_syscall_entry(current
, AUDIT_ARCH_I386
,
654 regs
->rbx
, regs
->rcx
,
655 regs
->rdx
, regs
->rsi
);
657 audit_syscall_entry(current
, AUDIT_ARCH_X86_64
,
659 regs
->rdi
, regs
->rsi
,
660 regs
->rdx
, regs
->r10
);
665 asmlinkage
void syscall_trace_leave(struct pt_regs
*regs
)
667 if (unlikely(current
->audit_context
))
668 audit_syscall_exit(current
, AUDITSC_RESULT(regs
->rax
), regs
->rax
);
670 if ((test_thread_flag(TIF_SYSCALL_TRACE
)
671 || test_thread_flag(TIF_SINGLESTEP
))
672 && (current
->ptrace
& PT_PTRACED
))