]>
Commit | Line | Data |
---|---|---|
1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * linux/arch/x86_64/ia32/ia32_signal.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | * | |
7 | * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson | |
8 | * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes | |
9 | * 2000-12-* x86-64 compatibility mode signal handling by Andi Kleen | |
10 | */ | |
11 | ||
12 | #include <linux/sched.h> | |
13 | #include <linux/sched/task_stack.h> | |
14 | #include <linux/mm.h> | |
15 | #include <linux/smp.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/errno.h> | |
18 | #include <linux/wait.h> | |
19 | #include <linux/unistd.h> | |
20 | #include <linux/stddef.h> | |
21 | #include <linux/personality.h> | |
22 | #include <linux/compat.h> | |
23 | #include <linux/binfmts.h> | |
24 | #include <asm/ucontext.h> | |
25 | #include <linux/uaccess.h> | |
26 | #include <asm/fpu/internal.h> | |
27 | #include <asm/fpu/signal.h> | |
28 | #include <asm/ptrace.h> | |
29 | #include <asm/ia32_unistd.h> | |
30 | #include <asm/user32.h> | |
31 | #include <uapi/asm/sigcontext.h> | |
32 | #include <asm/proto.h> | |
33 | #include <asm/vdso.h> | |
34 | #include <asm/sigframe.h> | |
35 | #include <asm/sighandling.h> | |
36 | #include <asm/sys_ia32.h> | |
37 | #include <asm/smap.h> | |
38 | ||
39 | /* | |
40 | * Do a signal return; undo the signal stack. | |
41 | */ | |
42 | #define loadsegment_gs(v) load_gs_index(v) | |
43 | #define loadsegment_fs(v) loadsegment(fs, v) | |
44 | #define loadsegment_ds(v) loadsegment(ds, v) | |
45 | #define loadsegment_es(v) loadsegment(es, v) | |
46 | ||
47 | #define get_user_seg(seg) ({ unsigned int v; savesegment(seg, v); v; }) | |
48 | #define set_user_seg(seg, v) loadsegment_##seg(v) | |
49 | ||
50 | #define COPY(x) { \ | |
51 | get_user_ex(regs->x, &sc->x); \ | |
52 | } | |
53 | ||
54 | #define GET_SEG(seg) ({ \ | |
55 | unsigned short tmp; \ | |
56 | get_user_ex(tmp, &sc->seg); \ | |
57 | tmp; \ | |
58 | }) | |
59 | ||
60 | #define COPY_SEG_CPL3(seg) do { \ | |
61 | regs->seg = GET_SEG(seg) | 3; \ | |
62 | } while (0) | |
63 | ||
64 | #define RELOAD_SEG(seg) { \ | |
65 | unsigned int pre = GET_SEG(seg); \ | |
66 | unsigned int cur = get_user_seg(seg); \ | |
67 | pre |= 3; \ | |
68 | if (pre != cur) \ | |
69 | set_user_seg(seg, pre); \ | |
70 | } | |
71 | ||
72 | static int ia32_restore_sigcontext(struct pt_regs *regs, | |
73 | struct sigcontext_32 __user *sc) | |
74 | { | |
75 | unsigned int tmpflags, err = 0; | |
76 | void __user *buf; | |
77 | u32 tmp; | |
78 | ||
79 | /* Always make any pending restarted system calls return -EINTR */ | |
80 | current->restart_block.fn = do_no_restart_syscall; | |
81 | ||
82 | get_user_try { | |
83 | /* | |
84 | * Reload fs and gs if they have changed in the signal | |
85 | * handler. This does not handle long fs/gs base changes in | |
86 | * the handler, but does not clobber them at least in the | |
87 | * normal case. | |
88 | */ | |
89 | RELOAD_SEG(gs); | |
90 | RELOAD_SEG(fs); | |
91 | RELOAD_SEG(ds); | |
92 | RELOAD_SEG(es); | |
93 | ||
94 | COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx); | |
95 | COPY(dx); COPY(cx); COPY(ip); COPY(ax); | |
96 | /* Don't touch extended registers */ | |
97 | ||
98 | COPY_SEG_CPL3(cs); | |
99 | COPY_SEG_CPL3(ss); | |
100 | ||
101 | get_user_ex(tmpflags, &sc->flags); | |
102 | regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS); | |
103 | /* disable syscall checks */ | |
104 | regs->orig_ax = -1; | |
105 | ||
106 | get_user_ex(tmp, &sc->fpstate); | |
107 | buf = compat_ptr(tmp); | |
108 | } get_user_catch(err); | |
109 | ||
110 | err |= fpu__restore_sig(buf, 1); | |
111 | ||
112 | force_iret(); | |
113 | ||
114 | return err; | |
115 | } | |
116 | ||
117 | asmlinkage long sys32_sigreturn(void) | |
118 | { | |
119 | struct pt_regs *regs = current_pt_regs(); | |
120 | struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8); | |
121 | sigset_t set; | |
122 | ||
123 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
124 | goto badframe; | |
125 | if (__get_user(set.sig[0], &frame->sc.oldmask) | |
126 | || (_COMPAT_NSIG_WORDS > 1 | |
127 | && __copy_from_user((((char *) &set.sig) + 4), | |
128 | &frame->extramask, | |
129 | sizeof(frame->extramask)))) | |
130 | goto badframe; | |
131 | ||
132 | set_current_blocked(&set); | |
133 | ||
134 | if (ia32_restore_sigcontext(regs, &frame->sc)) | |
135 | goto badframe; | |
136 | return regs->ax; | |
137 | ||
138 | badframe: | |
139 | signal_fault(regs, frame, "32bit sigreturn"); | |
140 | return 0; | |
141 | } | |
142 | ||
143 | asmlinkage long sys32_rt_sigreturn(void) | |
144 | { | |
145 | struct pt_regs *regs = current_pt_regs(); | |
146 | struct rt_sigframe_ia32 __user *frame; | |
147 | sigset_t set; | |
148 | ||
149 | frame = (struct rt_sigframe_ia32 __user *)(regs->sp - 4); | |
150 | ||
151 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
152 | goto badframe; | |
153 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
154 | goto badframe; | |
155 | ||
156 | set_current_blocked(&set); | |
157 | ||
158 | if (ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext)) | |
159 | goto badframe; | |
160 | ||
161 | if (compat_restore_altstack(&frame->uc.uc_stack)) | |
162 | goto badframe; | |
163 | ||
164 | return regs->ax; | |
165 | ||
166 | badframe: | |
167 | signal_fault(regs, frame, "32bit rt sigreturn"); | |
168 | return 0; | |
169 | } | |
170 | ||
171 | /* | |
172 | * Set up a signal frame. | |
173 | */ | |
174 | ||
175 | static int ia32_setup_sigcontext(struct sigcontext_32 __user *sc, | |
176 | void __user *fpstate, | |
177 | struct pt_regs *regs, unsigned int mask) | |
178 | { | |
179 | int err = 0; | |
180 | ||
181 | put_user_try { | |
182 | put_user_ex(get_user_seg(gs), (unsigned int __user *)&sc->gs); | |
183 | put_user_ex(get_user_seg(fs), (unsigned int __user *)&sc->fs); | |
184 | put_user_ex(get_user_seg(ds), (unsigned int __user *)&sc->ds); | |
185 | put_user_ex(get_user_seg(es), (unsigned int __user *)&sc->es); | |
186 | ||
187 | put_user_ex(regs->di, &sc->di); | |
188 | put_user_ex(regs->si, &sc->si); | |
189 | put_user_ex(regs->bp, &sc->bp); | |
190 | put_user_ex(regs->sp, &sc->sp); | |
191 | put_user_ex(regs->bx, &sc->bx); | |
192 | put_user_ex(regs->dx, &sc->dx); | |
193 | put_user_ex(regs->cx, &sc->cx); | |
194 | put_user_ex(regs->ax, &sc->ax); | |
195 | put_user_ex(current->thread.trap_nr, &sc->trapno); | |
196 | put_user_ex(current->thread.error_code, &sc->err); | |
197 | put_user_ex(regs->ip, &sc->ip); | |
198 | put_user_ex(regs->cs, (unsigned int __user *)&sc->cs); | |
199 | put_user_ex(regs->flags, &sc->flags); | |
200 | put_user_ex(regs->sp, &sc->sp_at_signal); | |
201 | put_user_ex(regs->ss, (unsigned int __user *)&sc->ss); | |
202 | ||
203 | put_user_ex(ptr_to_compat(fpstate), &sc->fpstate); | |
204 | ||
205 | /* non-iBCS2 extensions.. */ | |
206 | put_user_ex(mask, &sc->oldmask); | |
207 | put_user_ex(current->thread.cr2, &sc->cr2); | |
208 | } put_user_catch(err); | |
209 | ||
210 | return err; | |
211 | } | |
212 | ||
213 | /* | |
214 | * Determine which stack to use.. | |
215 | */ | |
216 | static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, | |
217 | size_t frame_size, | |
218 | void __user **fpstate) | |
219 | { | |
220 | struct fpu *fpu = ¤t->thread.fpu; | |
221 | unsigned long sp; | |
222 | ||
223 | /* Default to using normal stack */ | |
224 | sp = regs->sp; | |
225 | ||
226 | /* This is the X/Open sanctioned signal stack switching. */ | |
227 | if (ksig->ka.sa.sa_flags & SA_ONSTACK) | |
228 | sp = sigsp(sp, ksig); | |
229 | /* This is the legacy signal stack switching. */ | |
230 | else if (regs->ss != __USER32_DS && | |
231 | !(ksig->ka.sa.sa_flags & SA_RESTORER) && | |
232 | ksig->ka.sa.sa_restorer) | |
233 | sp = (unsigned long) ksig->ka.sa.sa_restorer; | |
234 | ||
235 | if (fpu->initialized) { | |
236 | unsigned long fx_aligned, math_size; | |
237 | ||
238 | sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size); | |
239 | *fpstate = (struct _fpstate_32 __user *) sp; | |
240 | if (copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned, | |
241 | math_size) < 0) | |
242 | return (void __user *) -1L; | |
243 | } | |
244 | ||
245 | sp -= frame_size; | |
246 | /* Align the stack pointer according to the i386 ABI, | |
247 | * i.e. so that on function entry ((sp + 4) & 15) == 0. */ | |
248 | sp = ((sp + 4) & -16ul) - 4; | |
249 | return (void __user *) sp; | |
250 | } | |
251 | ||
252 | int ia32_setup_frame(int sig, struct ksignal *ksig, | |
253 | compat_sigset_t *set, struct pt_regs *regs) | |
254 | { | |
255 | struct sigframe_ia32 __user *frame; | |
256 | void __user *restorer; | |
257 | int err = 0; | |
258 | void __user *fpstate = NULL; | |
259 | ||
260 | /* copy_to_user optimizes that into a single 8 byte store */ | |
261 | static const struct { | |
262 | u16 poplmovl; | |
263 | u32 val; | |
264 | u16 int80; | |
265 | } __attribute__((packed)) code = { | |
266 | 0xb858, /* popl %eax ; movl $...,%eax */ | |
267 | __NR_ia32_sigreturn, | |
268 | 0x80cd, /* int $0x80 */ | |
269 | }; | |
270 | ||
271 | frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate); | |
272 | ||
273 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
274 | return -EFAULT; | |
275 | ||
276 | if (__put_user(sig, &frame->sig)) | |
277 | return -EFAULT; | |
278 | ||
279 | if (ia32_setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0])) | |
280 | return -EFAULT; | |
281 | ||
282 | if (_COMPAT_NSIG_WORDS > 1) { | |
283 | if (__copy_to_user(frame->extramask, &set->sig[1], | |
284 | sizeof(frame->extramask))) | |
285 | return -EFAULT; | |
286 | } | |
287 | ||
288 | if (ksig->ka.sa.sa_flags & SA_RESTORER) { | |
289 | restorer = ksig->ka.sa.sa_restorer; | |
290 | } else { | |
291 | /* Return stub is in 32bit vsyscall page */ | |
292 | if (current->mm->context.vdso) | |
293 | restorer = current->mm->context.vdso + | |
294 | vdso_image_32.sym___kernel_sigreturn; | |
295 | else | |
296 | restorer = &frame->retcode; | |
297 | } | |
298 | ||
299 | put_user_try { | |
300 | put_user_ex(ptr_to_compat(restorer), &frame->pretcode); | |
301 | ||
302 | /* | |
303 | * These are actually not used anymore, but left because some | |
304 | * gdb versions depend on them as a marker. | |
305 | */ | |
306 | put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode); | |
307 | } put_user_catch(err); | |
308 | ||
309 | if (err) | |
310 | return -EFAULT; | |
311 | ||
312 | /* Set up registers for signal handler */ | |
313 | regs->sp = (unsigned long) frame; | |
314 | regs->ip = (unsigned long) ksig->ka.sa.sa_handler; | |
315 | ||
316 | /* Make -mregparm=3 work */ | |
317 | regs->ax = sig; | |
318 | regs->dx = 0; | |
319 | regs->cx = 0; | |
320 | ||
321 | loadsegment(ds, __USER32_DS); | |
322 | loadsegment(es, __USER32_DS); | |
323 | ||
324 | regs->cs = __USER32_CS; | |
325 | regs->ss = __USER32_DS; | |
326 | ||
327 | return 0; | |
328 | } | |
329 | ||
330 | int ia32_setup_rt_frame(int sig, struct ksignal *ksig, | |
331 | compat_sigset_t *set, struct pt_regs *regs) | |
332 | { | |
333 | struct rt_sigframe_ia32 __user *frame; | |
334 | void __user *restorer; | |
335 | int err = 0; | |
336 | void __user *fpstate = NULL; | |
337 | ||
338 | /* __copy_to_user optimizes that into a single 8 byte store */ | |
339 | static const struct { | |
340 | u8 movl; | |
341 | u32 val; | |
342 | u16 int80; | |
343 | u8 pad; | |
344 | } __attribute__((packed)) code = { | |
345 | 0xb8, | |
346 | __NR_ia32_rt_sigreturn, | |
347 | 0x80cd, | |
348 | 0, | |
349 | }; | |
350 | ||
351 | frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate); | |
352 | ||
353 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
354 | return -EFAULT; | |
355 | ||
356 | put_user_try { | |
357 | put_user_ex(sig, &frame->sig); | |
358 | put_user_ex(ptr_to_compat(&frame->info), &frame->pinfo); | |
359 | put_user_ex(ptr_to_compat(&frame->uc), &frame->puc); | |
360 | ||
361 | /* Create the ucontext. */ | |
362 | if (boot_cpu_has(X86_FEATURE_XSAVE)) | |
363 | put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); | |
364 | else | |
365 | put_user_ex(0, &frame->uc.uc_flags); | |
366 | put_user_ex(0, &frame->uc.uc_link); | |
367 | compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp); | |
368 | ||
369 | if (ksig->ka.sa.sa_flags & SA_RESTORER) | |
370 | restorer = ksig->ka.sa.sa_restorer; | |
371 | else | |
372 | restorer = current->mm->context.vdso + | |
373 | vdso_image_32.sym___kernel_rt_sigreturn; | |
374 | put_user_ex(ptr_to_compat(restorer), &frame->pretcode); | |
375 | ||
376 | /* | |
377 | * Not actually used anymore, but left because some gdb | |
378 | * versions need it. | |
379 | */ | |
380 | put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode); | |
381 | } put_user_catch(err); | |
382 | ||
383 | err |= __copy_siginfo_to_user32(&frame->info, &ksig->info, false); | |
384 | err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate, | |
385 | regs, set->sig[0]); | |
386 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
387 | ||
388 | if (err) | |
389 | return -EFAULT; | |
390 | ||
391 | /* Set up registers for signal handler */ | |
392 | regs->sp = (unsigned long) frame; | |
393 | regs->ip = (unsigned long) ksig->ka.sa.sa_handler; | |
394 | ||
395 | /* Make -mregparm=3 work */ | |
396 | regs->ax = sig; | |
397 | regs->dx = (unsigned long) &frame->info; | |
398 | regs->cx = (unsigned long) &frame->uc; | |
399 | ||
400 | loadsegment(ds, __USER32_DS); | |
401 | loadsegment(es, __USER32_DS); | |
402 | ||
403 | regs->cs = __USER32_CS; | |
404 | regs->ss = __USER32_DS; | |
405 | ||
406 | return 0; | |
407 | } |