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