linux_ptrace.c revision 304188 
1/*-
2 * Copyright (c) 2001 Alexander Kabaev
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: stable/10/sys/i386/linux/linux_ptrace.c 304188 2016-08-15 21:10:41Z jhb $");
31
32#include "opt_cpu.h"
33
34#include <sys/param.h>
35#include <sys/lock.h>
36#include <sys/mutex.h>
37#include <sys/proc.h>
38#include <sys/ptrace.h>
39#include <sys/syscallsubr.h>
40#include <sys/systm.h>
41
42#include <machine/md_var.h>
43#include <machine/pcb.h>
44#include <machine/reg.h>
45
46#include <i386/linux/linux.h>
47#include <i386/linux/linux_proto.h>
48#include <compat/linux/linux_signal.h>
49
50#if !defined(CPU_DISABLE_SSE) && defined(I686_CPU)
51#define CPU_ENABLE_SSE
52#endif
53
54/*
55 *   Linux ptrace requests numbers. Mostly identical to FreeBSD,
56 *   except for MD ones and PT_ATTACH/PT_DETACH.
57 */
58#define	PTRACE_TRACEME		0
59#define	PTRACE_PEEKTEXT		1
60#define	PTRACE_PEEKDATA		2
61#define	PTRACE_PEEKUSR		3
62#define	PTRACE_POKETEXT		4
63#define	PTRACE_POKEDATA		5
64#define	PTRACE_POKEUSR		6
65#define	PTRACE_CONT		7
66#define	PTRACE_KILL		8
67#define	PTRACE_SINGLESTEP	9
68
69#define PTRACE_ATTACH		16
70#define PTRACE_DETACH		17
71
72#define	LINUX_PTRACE_SYSCALL	24
73
74#define PTRACE_GETREGS		12
75#define PTRACE_SETREGS		13
76#define PTRACE_GETFPREGS	14
77#define PTRACE_SETFPREGS	15
78#define PTRACE_GETFPXREGS	18
79#define PTRACE_SETFPXREGS	19
80
81#define PTRACE_SETOPTIONS	21
82
83/*
84 * Linux keeps debug registers at the following
85 * offset in the user struct
86 */
87#define LINUX_DBREG_OFFSET	252
88#define LINUX_DBREG_SIZE	(8*sizeof(l_int))
89
90static __inline int
91map_signum(int signum)
92{
93
94	signum = linux_to_bsd_signal(signum);
95	return ((signum == SIGSTOP)? 0 : signum);
96}
97
98struct linux_pt_reg {
99	l_long	ebx;
100	l_long	ecx;
101	l_long	edx;
102	l_long	esi;
103	l_long	edi;
104	l_long	ebp;
105	l_long	eax;
106	l_int	xds;
107	l_int	xes;
108	l_int	xfs;
109	l_int	xgs;
110	l_long	orig_eax;
111	l_long	eip;
112	l_int	xcs;
113	l_long	eflags;
114	l_long	esp;
115	l_int	xss;
116};
117
118/*
119 *   Translate i386 ptrace registers between Linux and FreeBSD formats.
120 *   The translation is pretty straighforward, for all registers, but
121 *   orig_eax on Linux side and r_trapno and r_err in FreeBSD
122 */
123static void
124map_regs_to_linux(struct reg *bsd_r, struct linux_pt_reg *linux_r)
125{
126	linux_r->ebx = bsd_r->r_ebx;
127	linux_r->ecx = bsd_r->r_ecx;
128	linux_r->edx = bsd_r->r_edx;
129	linux_r->esi = bsd_r->r_esi;
130	linux_r->edi = bsd_r->r_edi;
131	linux_r->ebp = bsd_r->r_ebp;
132	linux_r->eax = bsd_r->r_eax;
133	linux_r->xds = bsd_r->r_ds;
134	linux_r->xes = bsd_r->r_es;
135	linux_r->xfs = bsd_r->r_fs;
136	linux_r->xgs = bsd_r->r_gs;
137	linux_r->orig_eax = bsd_r->r_eax;
138	linux_r->eip = bsd_r->r_eip;
139	linux_r->xcs = bsd_r->r_cs;
140	linux_r->eflags = bsd_r->r_eflags;
141	linux_r->esp = bsd_r->r_esp;
142	linux_r->xss = bsd_r->r_ss;
143}
144
145static void
146map_regs_from_linux(struct reg *bsd_r, struct linux_pt_reg *linux_r)
147{
148	bsd_r->r_ebx = linux_r->ebx;
149	bsd_r->r_ecx = linux_r->ecx;
150	bsd_r->r_edx = linux_r->edx;
151	bsd_r->r_esi = linux_r->esi;
152	bsd_r->r_edi = linux_r->edi;
153	bsd_r->r_ebp = linux_r->ebp;
154	bsd_r->r_eax = linux_r->eax;
155	bsd_r->r_ds  = linux_r->xds;
156	bsd_r->r_es  = linux_r->xes;
157	bsd_r->r_fs  = linux_r->xfs;
158	bsd_r->r_gs  = linux_r->xgs;
159	bsd_r->r_eip = linux_r->eip;
160	bsd_r->r_cs  = linux_r->xcs;
161	bsd_r->r_eflags = linux_r->eflags;
162	bsd_r->r_esp = linux_r->esp;
163	bsd_r->r_ss = linux_r->xss;
164}
165
166struct linux_pt_fpreg {
167	l_long cwd;
168	l_long swd;
169	l_long twd;
170	l_long fip;
171	l_long fcs;
172	l_long foo;
173	l_long fos;
174	l_long st_space[2*10];
175};
176
177static void
178map_fpregs_to_linux(struct fpreg *bsd_r, struct linux_pt_fpreg *linux_r)
179{
180	linux_r->cwd = bsd_r->fpr_env[0];
181	linux_r->swd = bsd_r->fpr_env[1];
182	linux_r->twd = bsd_r->fpr_env[2];
183	linux_r->fip = bsd_r->fpr_env[3];
184	linux_r->fcs = bsd_r->fpr_env[4];
185	linux_r->foo = bsd_r->fpr_env[5];
186	linux_r->fos = bsd_r->fpr_env[6];
187	bcopy(bsd_r->fpr_acc, linux_r->st_space, sizeof(linux_r->st_space));
188}
189
190static void
191map_fpregs_from_linux(struct fpreg *bsd_r, struct linux_pt_fpreg *linux_r)
192{
193	bsd_r->fpr_env[0] = linux_r->cwd;
194	bsd_r->fpr_env[1] = linux_r->swd;
195	bsd_r->fpr_env[2] = linux_r->twd;
196	bsd_r->fpr_env[3] = linux_r->fip;
197	bsd_r->fpr_env[4] = linux_r->fcs;
198	bsd_r->fpr_env[5] = linux_r->foo;
199	bsd_r->fpr_env[6] = linux_r->fos;
200	bcopy(bsd_r->fpr_acc, linux_r->st_space, sizeof(bsd_r->fpr_acc));
201}
202
203struct linux_pt_fpxreg {
204	l_ushort	cwd;
205	l_ushort	swd;
206	l_ushort	twd;
207	l_ushort	fop;
208	l_long		fip;
209	l_long		fcs;
210	l_long		foo;
211	l_long		fos;
212	l_long		mxcsr;
213	l_long		reserved;
214	l_long		st_space[32];
215	l_long		xmm_space[32];
216	l_long		padding[56];
217};
218
219#ifdef CPU_ENABLE_SSE
220static int
221linux_proc_read_fpxregs(struct thread *td, struct linux_pt_fpxreg *fpxregs)
222{
223
224	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
225	if (cpu_fxsr == 0 || (td->td_proc->p_flag & P_INMEM) == 0)
226		return (EIO);
227	bcopy(&get_pcb_user_save_td(td)->sv_xmm, fpxregs, sizeof(*fpxregs));
228	return (0);
229}
230
231static int
232linux_proc_write_fpxregs(struct thread *td, struct linux_pt_fpxreg *fpxregs)
233{
234
235	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
236	if (cpu_fxsr == 0 || (td->td_proc->p_flag & P_INMEM) == 0)
237		return (EIO);
238	bcopy(fpxregs, &get_pcb_user_save_td(td)->sv_xmm, sizeof(*fpxregs));
239	return (0);
240}
241#endif
242
243int
244linux_ptrace(struct thread *td, struct linux_ptrace_args *uap)
245{
246	union {
247		struct linux_pt_reg	reg;
248		struct linux_pt_fpreg	fpreg;
249		struct linux_pt_fpxreg	fpxreg;
250	} r;
251	union {
252		struct reg		bsd_reg;
253		struct fpreg		bsd_fpreg;
254		struct dbreg		bsd_dbreg;
255	} u;
256	void *addr;
257	pid_t pid;
258	int error, req;
259
260	error = 0;
261
262	/* by default, just copy data intact */
263	req  = uap->req;
264	pid  = (pid_t)uap->pid;
265	addr = (void *)uap->addr;
266
267	switch (req) {
268	case PTRACE_TRACEME:
269	case PTRACE_POKETEXT:
270	case PTRACE_POKEDATA:
271	case PTRACE_KILL:
272		error = kern_ptrace(td, req, pid, addr, uap->data);
273		break;
274	case PTRACE_PEEKTEXT:
275	case PTRACE_PEEKDATA: {
276		/* need to preserve return value */
277		int rval = td->td_retval[0];
278		error = kern_ptrace(td, req, pid, addr, 0);
279		if (error == 0)
280			error = copyout(td->td_retval, (void *)uap->data,
281			    sizeof(l_int));
282		td->td_retval[0] = rval;
283		break;
284	}
285	case PTRACE_DETACH:
286		error = kern_ptrace(td, PT_DETACH, pid, (void *)1,
287		     map_signum(uap->data));
288		break;
289	case PTRACE_SINGLESTEP:
290	case PTRACE_CONT:
291		error = kern_ptrace(td, req, pid, (void *)1,
292		     map_signum(uap->data));
293		break;
294	case PTRACE_ATTACH:
295		error = kern_ptrace(td, PT_ATTACH, pid, addr, uap->data);
296		break;
297	case PTRACE_GETREGS:
298		/* Linux is using data where FreeBSD is using addr */
299		error = kern_ptrace(td, PT_GETREGS, pid, &u.bsd_reg, 0);
300		if (error == 0) {
301			map_regs_to_linux(&u.bsd_reg, &r.reg);
302			error = copyout(&r.reg, (void *)uap->data,
303			    sizeof(r.reg));
304		}
305		break;
306	case PTRACE_SETREGS:
307		/* Linux is using data where FreeBSD is using addr */
308		error = copyin((void *)uap->data, &r.reg, sizeof(r.reg));
309		if (error == 0) {
310			map_regs_from_linux(&u.bsd_reg, &r.reg);
311			error = kern_ptrace(td, PT_SETREGS, pid, &u.bsd_reg, 0);
312		}
313		break;
314	case PTRACE_GETFPREGS:
315		/* Linux is using data where FreeBSD is using addr */
316		error = kern_ptrace(td, PT_GETFPREGS, pid, &u.bsd_fpreg, 0);
317		if (error == 0) {
318			map_fpregs_to_linux(&u.bsd_fpreg, &r.fpreg);
319			error = copyout(&r.fpreg, (void *)uap->data,
320			    sizeof(r.fpreg));
321		}
322		break;
323	case PTRACE_SETFPREGS:
324		/* Linux is using data where FreeBSD is using addr */
325		error = copyin((void *)uap->data, &r.fpreg, sizeof(r.fpreg));
326		if (error == 0) {
327			map_fpregs_from_linux(&u.bsd_fpreg, &r.fpreg);
328			error = kern_ptrace(td, PT_SETFPREGS, pid,
329			    &u.bsd_fpreg, 0);
330		}
331		break;
332	case PTRACE_SETFPXREGS:
333#ifdef CPU_ENABLE_SSE
334		error = copyin((void *)uap->data, &r.fpxreg, sizeof(r.fpxreg));
335		if (error)
336			break;
337#endif
338		/* FALL THROUGH */
339	case PTRACE_GETFPXREGS: {
340#ifdef CPU_ENABLE_SSE
341		struct proc *p;
342		struct thread *td2;
343
344		if (sizeof(struct linux_pt_fpxreg) != sizeof(struct savexmm)) {
345			static int once = 0;
346			if (!once) {
347				printf("linux: savexmm != linux_pt_fpxreg\n");
348				once = 1;
349			}
350			error = EIO;
351			break;
352		}
353
354		if ((p = pfind(uap->pid)) == NULL) {
355			error = ESRCH;
356			break;
357		}
358
359		/* Exiting processes can't be debugged. */
360		if ((p->p_flag & P_WEXIT) != 0) {
361			error = ESRCH;
362			goto fail;
363		}
364
365		if ((error = p_candebug(td, p)) != 0)
366			goto fail;
367
368		/* System processes can't be debugged. */
369		if ((p->p_flag & P_SYSTEM) != 0) {
370			error = EINVAL;
371			goto fail;
372		}
373
374		/* not being traced... */
375		if ((p->p_flag & P_TRACED) == 0) {
376			error = EPERM;
377			goto fail;
378		}
379
380		/* not being traced by YOU */
381		if (p->p_pptr != td->td_proc) {
382			error = EBUSY;
383			goto fail;
384		}
385
386		/* not currently stopped */
387		if (!P_SHOULDSTOP(p) || (p->p_flag & P_WAITED) == 0) {
388			error = EBUSY;
389			goto fail;
390		}
391
392		if (req == PTRACE_GETFPXREGS) {
393			_PHOLD(p);	/* may block */
394			td2 = FIRST_THREAD_IN_PROC(p);
395			error = linux_proc_read_fpxregs(td2, &r.fpxreg);
396			_PRELE(p);
397			PROC_UNLOCK(p);
398			if (error == 0)
399				error = copyout(&r.fpxreg, (void *)uap->data,
400				    sizeof(r.fpxreg));
401		} else {
402			/* clear dangerous bits exactly as Linux does*/
403			r.fpxreg.mxcsr &= 0xffbf;
404			_PHOLD(p);	/* may block */
405			td2 = FIRST_THREAD_IN_PROC(p);
406			error = linux_proc_write_fpxregs(td2, &r.fpxreg);
407			_PRELE(p);
408			PROC_UNLOCK(p);
409		}
410		break;
411
412	fail:
413		PROC_UNLOCK(p);
414#else
415		error = EIO;
416#endif
417		break;
418	}
419	case PTRACE_PEEKUSR:
420	case PTRACE_POKEUSR: {
421		error = EIO;
422
423		/* check addr for alignment */
424		if (uap->addr < 0 || uap->addr & (sizeof(l_int) - 1))
425			break;
426		/*
427		 * Allow linux programs to access register values in
428		 * user struct. We simulate this through PT_GET/SETREGS
429		 * as necessary.
430		 */
431		if (uap->addr < sizeof(struct linux_pt_reg)) {
432			error = kern_ptrace(td, PT_GETREGS, pid, &u.bsd_reg, 0);
433			if (error != 0)
434				break;
435
436			map_regs_to_linux(&u.bsd_reg, &r.reg);
437			if (req == PTRACE_PEEKUSR) {
438				error = copyout((char *)&r.reg + uap->addr,
439				    (void *)uap->data, sizeof(l_int));
440				break;
441			}
442
443			*(l_int *)((char *)&r.reg + uap->addr) =
444			    (l_int)uap->data;
445
446			map_regs_from_linux(&u.bsd_reg, &r.reg);
447			error = kern_ptrace(td, PT_SETREGS, pid, &u.bsd_reg, 0);
448		}
449
450		/*
451		 * Simulate debug registers access
452		 */
453		if (uap->addr >= LINUX_DBREG_OFFSET &&
454		    uap->addr <= LINUX_DBREG_OFFSET + LINUX_DBREG_SIZE) {
455			error = kern_ptrace(td, PT_GETDBREGS, pid, &u.bsd_dbreg,
456			    0);
457			if (error != 0)
458				break;
459
460			uap->addr -= LINUX_DBREG_OFFSET;
461			if (req == PTRACE_PEEKUSR) {
462				error = copyout((char *)&u.bsd_dbreg +
463				    uap->addr, (void *)uap->data,
464				    sizeof(l_int));
465				break;
466			}
467
468			*(l_int *)((char *)&u.bsd_dbreg + uap->addr) =
469			     uap->data;
470			error = kern_ptrace(td, PT_SETDBREGS, pid,
471			    &u.bsd_dbreg, 0);
472		}
473
474		break;
475	}
476	case LINUX_PTRACE_SYSCALL:
477		/* fall through */
478	default:
479		printf("linux: ptrace(%u, ...) not implemented\n",
480		    (unsigned int)uap->req);
481		error = EINVAL;
482		break;
483	}
484
485	return (error);
486}
487