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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
1da177e4 | 3 | * Copyright (C) 1991, 1992 Linus Torvalds |
e5fa2d06 | 4 | * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs |
1da177e4 LT |
5 | * |
6 | * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson | |
7 | * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes | |
e5fa2d06 | 8 | * 2000-2002 x86-64 support by Andi Kleen |
1da177e4 | 9 | */ |
c767a54b JP |
10 | |
11 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
12 | ||
5c9b3a0c | 13 | #include <linux/sched.h> |
68db0cf1 | 14 | #include <linux/sched/task_stack.h> |
5c9b3a0c HS |
15 | #include <linux/mm.h> |
16 | #include <linux/smp.h> | |
1da177e4 | 17 | #include <linux/kernel.h> |
1da177e4 LT |
18 | #include <linux/errno.h> |
19 | #include <linux/wait.h> | |
36a03308 | 20 | #include <linux/tracehook.h> |
5c9b3a0c HS |
21 | #include <linux/unistd.h> |
22 | #include <linux/stddef.h> | |
23 | #include <linux/personality.h> | |
24 | #include <linux/uaccess.h> | |
7c68af6e | 25 | #include <linux/user-return-notifier.h> |
0326f5a9 | 26 | #include <linux/uprobes.h> |
91d1aa43 | 27 | #include <linux/context_tracking.h> |
4c8ca51a | 28 | #include <linux/syscalls.h> |
7e907f48 | 29 | |
1da177e4 LT |
30 | #include <asm/processor.h> |
31 | #include <asm/ucontext.h> | |
78f7f1e5 | 32 | #include <asm/fpu/internal.h> |
fcbc99c4 | 33 | #include <asm/fpu/signal.h> |
6c3652ef | 34 | #include <asm/vdso.h> |
4efc0670 | 35 | #include <asm/mce.h> |
f28f0c23 | 36 | #include <asm/sighandling.h> |
ba3e127e | 37 | #include <asm/vm86.h> |
5c9b3a0c HS |
38 | |
39 | #ifdef CONFIG_X86_64 | |
40 | #include <asm/proto.h> | |
41 | #include <asm/ia32_unistd.h> | |
5c9b3a0c HS |
42 | #endif /* CONFIG_X86_64 */ |
43 | ||
bb57925f | 44 | #include <asm/syscall.h> |
bbc1f698 | 45 | #include <asm/syscalls.h> |
7e907f48 | 46 | |
41af86fa | 47 | #include <asm/sigframe.h> |
68463510 | 48 | #include <asm/signal.h> |
1da177e4 | 49 | |
8ff5bd2e AL |
50 | #ifdef CONFIG_X86_64 |
51 | /* | |
52 | * If regs->ss will cause an IRET fault, change it. Otherwise leave it | |
53 | * alone. Using this generally makes no sense unless | |
54 | * user_64bit_mode(regs) would return true. | |
55 | */ | |
56 | static void force_valid_ss(struct pt_regs *regs) | |
57 | { | |
58 | u32 ar; | |
59 | asm volatile ("lar %[old_ss], %[ar]\n\t" | |
60 | "jz 1f\n\t" /* If invalid: */ | |
61 | "xorl %[ar], %[ar]\n\t" /* set ar = 0 */ | |
62 | "1:" | |
63 | : [ar] "=r" (ar) | |
64 | : [old_ss] "rm" ((u16)regs->ss)); | |
65 | ||
66 | /* | |
67 | * For a valid 64-bit user context, we need DPL 3, type | |
68 | * read-write data or read-write exp-down data, and S and P | |
69 | * set. We can't use VERW because VERW doesn't check the | |
70 | * P bit. | |
71 | */ | |
72 | ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK; | |
73 | if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) && | |
74 | ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN)) | |
75 | regs->ss = __USER_DS; | |
76 | } | |
3add42c2 AV |
77 | # define CONTEXT_COPY_SIZE offsetof(struct sigcontext, reserved1) |
78 | #else | |
79 | # define CONTEXT_COPY_SIZE sizeof(struct sigcontext) | |
8ff5bd2e AL |
80 | #endif |
81 | ||
6c25da5a | 82 | static int restore_sigcontext(struct pt_regs *regs, |
3add42c2 | 83 | struct sigcontext __user *usc, |
6c25da5a | 84 | unsigned long uc_flags) |
2601657d | 85 | { |
3add42c2 | 86 | struct sigcontext sc; |
2601657d HS |
87 | |
88 | /* Always make any pending restarted system calls return -EINTR */ | |
f56141e3 | 89 | current->restart_block.fn = do_no_restart_syscall; |
2601657d | 90 | |
3add42c2 AV |
91 | if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE)) |
92 | return -EFAULT; | |
98e3d45e | 93 | |
2601657d | 94 | #ifdef CONFIG_X86_32 |
3add42c2 AV |
95 | set_user_gs(regs, sc.gs); |
96 | regs->fs = sc.fs; | |
97 | regs->es = sc.es; | |
98 | regs->ds = sc.ds; | |
2601657d HS |
99 | #endif /* CONFIG_X86_32 */ |
100 | ||
3add42c2 AV |
101 | regs->bx = sc.bx; |
102 | regs->cx = sc.cx; | |
103 | regs->dx = sc.dx; | |
104 | regs->si = sc.si; | |
105 | regs->di = sc.di; | |
106 | regs->bp = sc.bp; | |
107 | regs->ax = sc.ax; | |
108 | regs->sp = sc.sp; | |
109 | regs->ip = sc.ip; | |
2601657d HS |
110 | |
111 | #ifdef CONFIG_X86_64 | |
3add42c2 AV |
112 | regs->r8 = sc.r8; |
113 | regs->r9 = sc.r9; | |
114 | regs->r10 = sc.r10; | |
115 | regs->r11 = sc.r11; | |
116 | regs->r12 = sc.r12; | |
117 | regs->r13 = sc.r13; | |
118 | regs->r14 = sc.r14; | |
119 | regs->r15 = sc.r15; | |
2601657d HS |
120 | #endif /* CONFIG_X86_64 */ |
121 | ||
3add42c2 AV |
122 | /* Get CS/SS and force CPL3 */ |
123 | regs->cs = sc.cs | 0x03; | |
124 | regs->ss = sc.ss | 0x03; | |
98e3d45e | 125 | |
3add42c2 AV |
126 | regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS); |
127 | /* disable syscall checks */ | |
128 | regs->orig_ax = -1; | |
2601657d | 129 | |
88e47182 PZ |
130 | #ifdef CONFIG_X86_64 |
131 | /* | |
132 | * Fix up SS if needed for the benefit of old DOSEMU and | |
133 | * CRIU. | |
134 | */ | |
135 | if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && user_64bit_mode(regs))) | |
136 | force_valid_ss(regs); | |
137 | #endif | |
138 | ||
3add42c2 AV |
139 | return fpu__restore_sig((void __user *)sc.fpstate, |
140 | IS_ENABLED(CONFIG_X86_32)); | |
2601657d HS |
141 | } |
142 | ||
85139422 PA |
143 | int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, |
144 | struct pt_regs *regs, unsigned long mask) | |
2601657d HS |
145 | { |
146 | int err = 0; | |
147 | ||
98e3d45e | 148 | put_user_try { |
2601657d | 149 | |
98e3d45e | 150 | #ifdef CONFIG_X86_32 |
d9a89a26 | 151 | put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs); |
98e3d45e HS |
152 | put_user_ex(regs->fs, (unsigned int __user *)&sc->fs); |
153 | put_user_ex(regs->es, (unsigned int __user *)&sc->es); | |
154 | put_user_ex(regs->ds, (unsigned int __user *)&sc->ds); | |
2601657d HS |
155 | #endif /* CONFIG_X86_32 */ |
156 | ||
98e3d45e HS |
157 | put_user_ex(regs->di, &sc->di); |
158 | put_user_ex(regs->si, &sc->si); | |
159 | put_user_ex(regs->bp, &sc->bp); | |
160 | put_user_ex(regs->sp, &sc->sp); | |
161 | put_user_ex(regs->bx, &sc->bx); | |
162 | put_user_ex(regs->dx, &sc->dx); | |
163 | put_user_ex(regs->cx, &sc->cx); | |
164 | put_user_ex(regs->ax, &sc->ax); | |
2601657d | 165 | #ifdef CONFIG_X86_64 |
98e3d45e HS |
166 | put_user_ex(regs->r8, &sc->r8); |
167 | put_user_ex(regs->r9, &sc->r9); | |
168 | put_user_ex(regs->r10, &sc->r10); | |
169 | put_user_ex(regs->r11, &sc->r11); | |
170 | put_user_ex(regs->r12, &sc->r12); | |
171 | put_user_ex(regs->r13, &sc->r13); | |
172 | put_user_ex(regs->r14, &sc->r14); | |
173 | put_user_ex(regs->r15, &sc->r15); | |
2601657d HS |
174 | #endif /* CONFIG_X86_64 */ |
175 | ||
51e7dc70 | 176 | put_user_ex(current->thread.trap_nr, &sc->trapno); |
98e3d45e HS |
177 | put_user_ex(current->thread.error_code, &sc->err); |
178 | put_user_ex(regs->ip, &sc->ip); | |
2601657d | 179 | #ifdef CONFIG_X86_32 |
98e3d45e HS |
180 | put_user_ex(regs->cs, (unsigned int __user *)&sc->cs); |
181 | put_user_ex(regs->flags, &sc->flags); | |
182 | put_user_ex(regs->sp, &sc->sp_at_signal); | |
183 | put_user_ex(regs->ss, (unsigned int __user *)&sc->ss); | |
2601657d | 184 | #else /* !CONFIG_X86_32 */ |
98e3d45e HS |
185 | put_user_ex(regs->flags, &sc->flags); |
186 | put_user_ex(regs->cs, &sc->cs); | |
ed596cde LT |
187 | put_user_ex(0, &sc->gs); |
188 | put_user_ex(0, &sc->fs); | |
6c25da5a | 189 | put_user_ex(regs->ss, &sc->ss); |
2601657d HS |
190 | #endif /* CONFIG_X86_32 */ |
191 | ||
89833fab | 192 | put_user_ex(fpstate, (unsigned long __user *)&sc->fpstate); |
2601657d | 193 | |
98e3d45e HS |
194 | /* non-iBCS2 extensions.. */ |
195 | put_user_ex(mask, &sc->oldmask); | |
196 | put_user_ex(current->thread.cr2, &sc->cr2); | |
197 | } put_user_catch(err); | |
2601657d HS |
198 | |
199 | return err; | |
200 | } | |
201 | ||
1da177e4 | 202 | /* |
bfeb91a9 | 203 | * Set up a signal frame. |
1da177e4 | 204 | */ |
1da177e4 LT |
205 | |
206 | /* | |
207 | * Determine which stack to use.. | |
208 | */ | |
1fae0279 HS |
209 | static unsigned long align_sigframe(unsigned long sp) |
210 | { | |
211 | #ifdef CONFIG_X86_32 | |
212 | /* | |
213 | * Align the stack pointer according to the i386 ABI, | |
214 | * i.e. so that on function entry ((sp + 4) & 15) == 0. | |
215 | */ | |
216 | sp = ((sp + 4) & -16ul) - 4; | |
217 | #else /* !CONFIG_X86_32 */ | |
218 | sp = round_down(sp, 16) - 8; | |
219 | #endif | |
220 | return sp; | |
221 | } | |
222 | ||
dae0f305 | 223 | static void __user * |
3c1c7f10 | 224 | get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, |
144b0712 | 225 | void __user **fpstate) |
1da177e4 | 226 | { |
1da177e4 | 227 | /* Default to using normal stack */ |
72a671ce | 228 | unsigned long math_size = 0; |
75779f05 | 229 | unsigned long sp = regs->sp; |
72a671ce | 230 | unsigned long buf_fx = 0; |
14fc9fbc | 231 | int onsigstack = on_sig_stack(sp); |
2722146e | 232 | int ret; |
75779f05 | 233 | |
75779f05 | 234 | /* redzone */ |
97f2645f | 235 | if (IS_ENABLED(CONFIG_X86_64)) |
050902c0 | 236 | sp -= 128; |
1da177e4 | 237 | |
0b4521e8 SS |
238 | /* This is the X/Open sanctioned signal stack switching. */ |
239 | if (ka->sa.sa_flags & SA_ONSTACK) { | |
240 | if (sas_ss_flags(sp) == 0) | |
241 | sp = current->sas_ss_sp + current->sas_ss_size; | |
97f2645f | 242 | } else if (IS_ENABLED(CONFIG_X86_32) && |
0b4521e8 | 243 | !onsigstack && |
99504819 | 244 | regs->ss != __USER_DS && |
0b4521e8 SS |
245 | !(ka->sa.sa_flags & SA_RESTORER) && |
246 | ka->sa.sa_restorer) { | |
247 | /* This is the legacy signal stack switching. */ | |
248 | sp = (unsigned long) ka->sa.sa_restorer; | |
1da177e4 LT |
249 | } |
250 | ||
2722146e SAS |
251 | sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32), |
252 | &buf_fx, &math_size); | |
253 | *fpstate = (void __user *)sp; | |
3c1c7f10 | 254 | |
14fc9fbc HS |
255 | sp = align_sigframe(sp - frame_size); |
256 | ||
257 | /* | |
258 | * If we are on the alternate signal stack and would overflow it, don't. | |
259 | * Return an always-bogus address instead so we will die with SIGSEGV. | |
260 | */ | |
261 | if (onsigstack && !likely(on_sig_stack(sp))) | |
262 | return (void __user *)-1L; | |
263 | ||
72a671ce | 264 | /* save i387 and extended state */ |
2722146e SAS |
265 | ret = copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size); |
266 | if (ret < 0) | |
14fc9fbc HS |
267 | return (void __user *)-1L; |
268 | ||
269 | return (void __user *)sp; | |
1da177e4 LT |
270 | } |
271 | ||
75779f05 HS |
272 | #ifdef CONFIG_X86_32 |
273 | static const struct { | |
274 | u16 poplmovl; | |
275 | u32 val; | |
276 | u16 int80; | |
277 | } __attribute__((packed)) retcode = { | |
278 | 0xb858, /* popl %eax; movl $..., %eax */ | |
279 | __NR_sigreturn, | |
280 | 0x80cd, /* int $0x80 */ | |
281 | }; | |
282 | ||
283 | static const struct { | |
284 | u8 movl; | |
285 | u32 val; | |
286 | u16 int80; | |
287 | u8 pad; | |
288 | } __attribute__((packed)) rt_retcode = { | |
289 | 0xb8, /* movl $..., %eax */ | |
290 | __NR_rt_sigreturn, | |
291 | 0x80cd, /* int $0x80 */ | |
292 | 0 | |
293 | }; | |
294 | ||
7e907f48 | 295 | static int |
235b8022 | 296 | __setup_frame(int sig, struct ksignal *ksig, sigset_t *set, |
1d13024e | 297 | struct pt_regs *regs) |
1da177e4 | 298 | { |
1da177e4 | 299 | struct sigframe __user *frame; |
7e907f48 | 300 | void __user *restorer; |
1da177e4 | 301 | int err = 0; |
ab513701 | 302 | void __user *fpstate = NULL; |
1da177e4 | 303 | |
235b8022 | 304 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); |
1da177e4 | 305 | |
96d4f267 | 306 | if (!access_ok(frame, sizeof(*frame))) |
3d0aedd9 | 307 | return -EFAULT; |
1da177e4 | 308 | |
2ba48e16 | 309 | if (__put_user(sig, &frame->sig)) |
3d0aedd9 | 310 | return -EFAULT; |
1da177e4 | 311 | |
2ba48e16 | 312 | if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0])) |
3d0aedd9 | 313 | return -EFAULT; |
1da177e4 | 314 | |
71c3313a AV |
315 | if (__put_user(set->sig[1], &frame->extramask[0])) |
316 | return -EFAULT; | |
1da177e4 | 317 | |
1a3e4ca4 | 318 | if (current->mm->context.vdso) |
6f121e54 | 319 | restorer = current->mm->context.vdso + |
0a6d1fa0 | 320 | vdso_image_32.sym___kernel_sigreturn; |
9fbbd4dd | 321 | else |
ade1af77 | 322 | restorer = &frame->retcode; |
235b8022 AV |
323 | if (ksig->ka.sa.sa_flags & SA_RESTORER) |
324 | restorer = ksig->ka.sa.sa_restorer; | |
1da177e4 LT |
325 | |
326 | /* Set up to return from userspace. */ | |
327 | err |= __put_user(restorer, &frame->pretcode); | |
7e907f48 | 328 | |
1da177e4 | 329 | /* |
7e907f48 | 330 | * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 |
1da177e4 LT |
331 | * |
332 | * WE DO NOT USE IT ANY MORE! It's only left here for historical | |
333 | * reasons and because gdb uses it as a signature to notice | |
334 | * signal handler stack frames. | |
335 | */ | |
4a612048 | 336 | err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode); |
1da177e4 LT |
337 | |
338 | if (err) | |
3d0aedd9 | 339 | return -EFAULT; |
1da177e4 LT |
340 | |
341 | /* Set up registers for signal handler */ | |
7e907f48 | 342 | regs->sp = (unsigned long)frame; |
235b8022 | 343 | regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
7e907f48 | 344 | regs->ax = (unsigned long)sig; |
92bc2056 HH |
345 | regs->dx = 0; |
346 | regs->cx = 0; | |
1da177e4 | 347 | |
65ea5b03 PA |
348 | regs->ds = __USER_DS; |
349 | regs->es = __USER_DS; | |
350 | regs->ss = __USER_DS; | |
351 | regs->cs = __USER_CS; | |
1da177e4 | 352 | |
283828f3 | 353 | return 0; |
1da177e4 LT |
354 | } |
355 | ||
235b8022 | 356 | static int __setup_rt_frame(int sig, struct ksignal *ksig, |
1d13024e | 357 | sigset_t *set, struct pt_regs *regs) |
1da177e4 | 358 | { |
1da177e4 | 359 | struct rt_sigframe __user *frame; |
7e907f48 | 360 | void __user *restorer; |
1da177e4 | 361 | int err = 0; |
ab513701 | 362 | void __user *fpstate = NULL; |
1da177e4 | 363 | |
235b8022 | 364 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); |
1da177e4 | 365 | |
96d4f267 | 366 | if (!access_ok(frame, sizeof(*frame))) |
3d0aedd9 | 367 | return -EFAULT; |
1da177e4 | 368 | |
98e3d45e HS |
369 | put_user_try { |
370 | put_user_ex(sig, &frame->sig); | |
371 | put_user_ex(&frame->info, &frame->pinfo); | |
372 | put_user_ex(&frame->uc, &frame->puc); | |
98e3d45e HS |
373 | |
374 | /* Create the ucontext. */ | |
ff661350 | 375 | if (static_cpu_has(X86_FEATURE_XSAVE)) |
98e3d45e HS |
376 | put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); |
377 | else | |
378 | put_user_ex(0, &frame->uc.uc_flags); | |
379 | put_user_ex(0, &frame->uc.uc_link); | |
bd1c149a | 380 | save_altstack_ex(&frame->uc.uc_stack, regs->sp); |
98e3d45e HS |
381 | |
382 | /* Set up to return from userspace. */ | |
6f121e54 | 383 | restorer = current->mm->context.vdso + |
0a6d1fa0 | 384 | vdso_image_32.sym___kernel_rt_sigreturn; |
235b8022 AV |
385 | if (ksig->ka.sa.sa_flags & SA_RESTORER) |
386 | restorer = ksig->ka.sa.sa_restorer; | |
98e3d45e HS |
387 | put_user_ex(restorer, &frame->pretcode); |
388 | ||
389 | /* | |
390 | * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 | |
391 | * | |
392 | * WE DO NOT USE IT ANY MORE! It's only left here for historical | |
393 | * reasons and because gdb uses it as a signature to notice | |
394 | * signal handler stack frames. | |
395 | */ | |
396 | put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode); | |
397 | } put_user_catch(err); | |
49b8c695 | 398 | |
235b8022 | 399 | err |= copy_siginfo_to_user(&frame->info, &ksig->info); |
5e88353d PA |
400 | err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, |
401 | regs, set->sig[0]); | |
402 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
1da177e4 LT |
403 | |
404 | if (err) | |
3d0aedd9 | 405 | return -EFAULT; |
1da177e4 LT |
406 | |
407 | /* Set up registers for signal handler */ | |
7e907f48 | 408 | regs->sp = (unsigned long)frame; |
235b8022 | 409 | regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
13ad7725 | 410 | regs->ax = (unsigned long)sig; |
7e907f48 IM |
411 | regs->dx = (unsigned long)&frame->info; |
412 | regs->cx = (unsigned long)&frame->uc; | |
1da177e4 | 413 | |
65ea5b03 PA |
414 | regs->ds = __USER_DS; |
415 | regs->es = __USER_DS; | |
416 | regs->ss = __USER_DS; | |
417 | regs->cs = __USER_CS; | |
1da177e4 | 418 | |
283828f3 | 419 | return 0; |
1da177e4 | 420 | } |
bfeb91a9 | 421 | #else /* !CONFIG_X86_32 */ |
6c25da5a AL |
422 | static unsigned long frame_uc_flags(struct pt_regs *regs) |
423 | { | |
424 | unsigned long flags; | |
425 | ||
d366bf7e | 426 | if (boot_cpu_has(X86_FEATURE_XSAVE)) |
6c25da5a AL |
427 | flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS; |
428 | else | |
429 | flags = UC_SIGCONTEXT_SS; | |
430 | ||
431 | if (likely(user_64bit_mode(regs))) | |
432 | flags |= UC_STRICT_RESTORE_SS; | |
433 | ||
434 | return flags; | |
435 | } | |
436 | ||
235b8022 | 437 | static int __setup_rt_frame(int sig, struct ksignal *ksig, |
bfeb91a9 HS |
438 | sigset_t *set, struct pt_regs *regs) |
439 | { | |
440 | struct rt_sigframe __user *frame; | |
441 | void __user *fp = NULL; | |
88e47182 | 442 | unsigned long uc_flags; |
bfeb91a9 | 443 | int err = 0; |
bfeb91a9 | 444 | |
235b8022 | 445 | frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp); |
bfeb91a9 | 446 | |
96d4f267 | 447 | if (!access_ok(frame, sizeof(*frame))) |
bfeb91a9 HS |
448 | return -EFAULT; |
449 | ||
235b8022 AV |
450 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
451 | if (copy_siginfo_to_user(&frame->info, &ksig->info)) | |
bfeb91a9 HS |
452 | return -EFAULT; |
453 | } | |
454 | ||
88e47182 PZ |
455 | uc_flags = frame_uc_flags(regs); |
456 | ||
98e3d45e HS |
457 | put_user_try { |
458 | /* Create the ucontext. */ | |
88e47182 | 459 | put_user_ex(uc_flags, &frame->uc.uc_flags); |
98e3d45e | 460 | put_user_ex(0, &frame->uc.uc_link); |
bd1c149a | 461 | save_altstack_ex(&frame->uc.uc_stack, regs->sp); |
98e3d45e HS |
462 | |
463 | /* Set up to return from userspace. If provided, use a stub | |
464 | already in userspace. */ | |
465 | /* x86-64 should always use SA_RESTORER. */ | |
235b8022 AV |
466 | if (ksig->ka.sa.sa_flags & SA_RESTORER) { |
467 | put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode); | |
98e3d45e HS |
468 | } else { |
469 | /* could use a vstub here */ | |
470 | err |= -EFAULT; | |
471 | } | |
472 | } put_user_catch(err); | |
bfeb91a9 | 473 | |
5e88353d | 474 | err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]); |
71c3313a | 475 | err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); |
5e88353d | 476 | |
bfeb91a9 HS |
477 | if (err) |
478 | return -EFAULT; | |
479 | ||
480 | /* Set up registers for signal handler */ | |
481 | regs->di = sig; | |
482 | /* In case the signal handler was declared without prototypes */ | |
483 | regs->ax = 0; | |
484 | ||
485 | /* This also works for non SA_SIGINFO handlers because they expect the | |
486 | next argument after the signal number on the stack. */ | |
487 | regs->si = (unsigned long)&frame->info; | |
488 | regs->dx = (unsigned long)&frame->uc; | |
235b8022 | 489 | regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
bfeb91a9 HS |
490 | |
491 | regs->sp = (unsigned long)frame; | |
492 | ||
8ff5bd2e AL |
493 | /* |
494 | * Set up the CS and SS registers to run signal handlers in | |
495 | * 64-bit mode, even if the handler happens to be interrupting | |
496 | * 32-bit or 16-bit code. | |
497 | * | |
498 | * SS is subtle. In 64-bit mode, we don't need any particular | |
499 | * SS descriptor, but we do need SS to be valid. It's possible | |
500 | * that the old SS is entirely bogus -- this can happen if the | |
501 | * signal we're trying to deliver is #GP or #SS caused by a bad | |
502 | * SS value. We also have a compatbility issue here: DOSEMU | |
503 | * relies on the contents of the SS register indicating the | |
504 | * SS value at the time of the signal, even though that code in | |
505 | * DOSEMU predates sigreturn's ability to restore SS. (DOSEMU | |
506 | * avoids relying on sigreturn to restore SS; instead it uses | |
507 | * a trampoline.) So we do our best: if the old SS was valid, | |
508 | * we keep it. Otherwise we replace it. | |
509 | */ | |
bfeb91a9 HS |
510 | regs->cs = __USER_CS; |
511 | ||
8ff5bd2e AL |
512 | if (unlikely(regs->ss != __USER_DS)) |
513 | force_valid_ss(regs); | |
514 | ||
bfeb91a9 HS |
515 | return 0; |
516 | } | |
517 | #endif /* CONFIG_X86_32 */ | |
518 | ||
235b8022 AV |
519 | static int x32_setup_rt_frame(struct ksignal *ksig, |
520 | compat_sigset_t *set, | |
050902c0 SS |
521 | struct pt_regs *regs) |
522 | { | |
523 | #ifdef CONFIG_X86_X32_ABI | |
524 | struct rt_sigframe_x32 __user *frame; | |
88e47182 | 525 | unsigned long uc_flags; |
050902c0 SS |
526 | void __user *restorer; |
527 | int err = 0; | |
528 | void __user *fpstate = NULL; | |
529 | ||
235b8022 | 530 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); |
050902c0 | 531 | |
96d4f267 | 532 | if (!access_ok(frame, sizeof(*frame))) |
050902c0 SS |
533 | return -EFAULT; |
534 | ||
235b8022 | 535 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
68463510 | 536 | if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true)) |
050902c0 SS |
537 | return -EFAULT; |
538 | } | |
539 | ||
88e47182 PZ |
540 | uc_flags = frame_uc_flags(regs); |
541 | ||
050902c0 SS |
542 | put_user_try { |
543 | /* Create the ucontext. */ | |
88e47182 | 544 | put_user_ex(uc_flags, &frame->uc.uc_flags); |
050902c0 | 545 | put_user_ex(0, &frame->uc.uc_link); |
bd1c149a | 546 | compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp); |
050902c0 | 547 | put_user_ex(0, &frame->uc.uc__pad0); |
050902c0 | 548 | |
235b8022 AV |
549 | if (ksig->ka.sa.sa_flags & SA_RESTORER) { |
550 | restorer = ksig->ka.sa.sa_restorer; | |
050902c0 SS |
551 | } else { |
552 | /* could use a vstub here */ | |
553 | restorer = NULL; | |
554 | err |= -EFAULT; | |
555 | } | |
89833fab | 556 | put_user_ex(restorer, (unsigned long __user *)&frame->pretcode); |
050902c0 SS |
557 | } put_user_catch(err); |
558 | ||
49b8c695 PA |
559 | err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, |
560 | regs, set->sig[0]); | |
71c3313a | 561 | err |= __put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask); |
49b8c695 | 562 | |
050902c0 SS |
563 | if (err) |
564 | return -EFAULT; | |
565 | ||
566 | /* Set up registers for signal handler */ | |
567 | regs->sp = (unsigned long) frame; | |
235b8022 | 568 | regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
050902c0 SS |
569 | |
570 | /* We use the x32 calling convention here... */ | |
235b8022 | 571 | regs->di = ksig->sig; |
050902c0 SS |
572 | regs->si = (unsigned long) &frame->info; |
573 | regs->dx = (unsigned long) &frame->uc; | |
574 | ||
575 | loadsegment(ds, __USER_DS); | |
576 | loadsegment(es, __USER_DS); | |
577 | ||
578 | regs->cs = __USER_CS; | |
579 | regs->ss = __USER_DS; | |
580 | #endif /* CONFIG_X86_X32_ABI */ | |
581 | ||
582 | return 0; | |
583 | } | |
584 | ||
bfeb91a9 HS |
585 | /* |
586 | * Do a signal return; undo the signal stack. | |
587 | */ | |
e5fa2d06 | 588 | #ifdef CONFIG_X86_32 |
4c8ca51a | 589 | SYSCALL_DEFINE0(sigreturn) |
bfeb91a9 | 590 | { |
3fe26fa3 | 591 | struct pt_regs *regs = current_pt_regs(); |
bfeb91a9 | 592 | struct sigframe __user *frame; |
bfeb91a9 HS |
593 | sigset_t set; |
594 | ||
bfeb91a9 HS |
595 | frame = (struct sigframe __user *)(regs->sp - 8); |
596 | ||
96d4f267 | 597 | if (!access_ok(frame, sizeof(*frame))) |
bfeb91a9 | 598 | goto badframe; |
71c3313a AV |
599 | if (__get_user(set.sig[0], &frame->sc.oldmask) || |
600 | __get_user(set.sig[1], &frame->extramask[0])) | |
bfeb91a9 HS |
601 | goto badframe; |
602 | ||
3982294b | 603 | set_current_blocked(&set); |
bfeb91a9 | 604 | |
6c25da5a AL |
605 | /* |
606 | * x86_32 has no uc_flags bits relevant to restore_sigcontext. | |
607 | * Save a few cycles by skipping the __get_user. | |
608 | */ | |
609 | if (restore_sigcontext(regs, &frame->sc, 0)) | |
bfeb91a9 | 610 | goto badframe; |
6a3713f0 | 611 | return regs->ax; |
bfeb91a9 HS |
612 | |
613 | badframe: | |
ae417bb4 | 614 | signal_fault(regs, frame, "sigreturn"); |
bfeb91a9 HS |
615 | |
616 | return 0; | |
617 | } | |
e5fa2d06 | 618 | #endif /* CONFIG_X86_32 */ |
bfeb91a9 | 619 | |
4c8ca51a | 620 | SYSCALL_DEFINE0(rt_sigreturn) |
bfeb91a9 | 621 | { |
3fe26fa3 | 622 | struct pt_regs *regs = current_pt_regs(); |
bfeb91a9 | 623 | struct rt_sigframe __user *frame; |
bfeb91a9 | 624 | sigset_t set; |
6c25da5a | 625 | unsigned long uc_flags; |
bfeb91a9 HS |
626 | |
627 | frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long)); | |
96d4f267 | 628 | if (!access_ok(frame, sizeof(*frame))) |
bfeb91a9 | 629 | goto badframe; |
71c3313a | 630 | if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask)) |
bfeb91a9 | 631 | goto badframe; |
6c25da5a AL |
632 | if (__get_user(uc_flags, &frame->uc.uc_flags)) |
633 | goto badframe; | |
bfeb91a9 | 634 | |
e9bd3f0f | 635 | set_current_blocked(&set); |
bfeb91a9 | 636 | |
6c25da5a | 637 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
bfeb91a9 HS |
638 | goto badframe; |
639 | ||
c40702c4 | 640 | if (restore_altstack(&frame->uc.uc_stack)) |
bfeb91a9 HS |
641 | goto badframe; |
642 | ||
6a3713f0 | 643 | return regs->ax; |
bfeb91a9 HS |
644 | |
645 | badframe: | |
646 | signal_fault(regs, frame, "rt_sigreturn"); | |
647 | return 0; | |
648 | } | |
649 | ||
68463510 | 650 | static inline int is_ia32_compat_frame(struct ksignal *ksig) |
05012c13 | 651 | { |
97f2645f | 652 | return IS_ENABLED(CONFIG_IA32_EMULATION) && |
68463510 | 653 | ksig->ka.sa.sa_flags & SA_IA32_ABI; |
05012c13 IM |
654 | } |
655 | ||
68463510 | 656 | static inline int is_ia32_frame(struct ksignal *ksig) |
05012c13 | 657 | { |
68463510 | 658 | return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig); |
05012c13 IM |
659 | } |
660 | ||
68463510 | 661 | static inline int is_x32_frame(struct ksignal *ksig) |
05012c13 | 662 | { |
68463510 DS |
663 | return IS_ENABLED(CONFIG_X86_X32_ABI) && |
664 | ksig->ka.sa.sa_flags & SA_X32_ABI; | |
05012c13 IM |
665 | } |
666 | ||
1d13024e | 667 | static int |
235b8022 | 668 | setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) |
1d13024e | 669 | { |
3050a35f | 670 | int usig = ksig->sig; |
b7f9a11a | 671 | sigset_t *set = sigmask_to_save(); |
050902c0 | 672 | compat_sigset_t *cset = (compat_sigset_t *) set; |
1d13024e | 673 | |
bff9504b | 674 | /* Perform fixup for the pre-signal frame. */ |
784e0300 | 675 | rseq_signal_deliver(ksig, regs); |
d6761b8f | 676 | |
1d13024e | 677 | /* Set up the stack frame */ |
68463510 | 678 | if (is_ia32_frame(ksig)) { |
235b8022 AV |
679 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
680 | return ia32_setup_rt_frame(usig, ksig, cset, regs); | |
455edbc4 | 681 | else |
235b8022 | 682 | return ia32_setup_frame(usig, ksig, cset, regs); |
68463510 | 683 | } else if (is_x32_frame(ksig)) { |
235b8022 | 684 | return x32_setup_rt_frame(ksig, cset, regs); |
c5a37394 | 685 | } else { |
235b8022 | 686 | return __setup_rt_frame(ksig->sig, ksig, set, regs); |
c5a37394 | 687 | } |
1d13024e HS |
688 | } |
689 | ||
a610d6e6 | 690 | static void |
235b8022 | 691 | handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
1da177e4 | 692 | { |
fd0f86b6 | 693 | bool stepping, failed; |
c5bedc68 | 694 | struct fpu *fpu = ¤t->thread.fpu; |
fd0f86b6 | 695 | |
5ed92a8a BG |
696 | if (v8086_mode(regs)) |
697 | save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL); | |
698 | ||
1da177e4 | 699 | /* Are we from a system call? */ |
bb57925f | 700 | if (syscall_get_nr(current, regs) >= 0) { |
1da177e4 | 701 | /* If so, check system call restarting.. */ |
bb57925f | 702 | switch (syscall_get_error(current, regs)) { |
ac66f3fd HH |
703 | case -ERESTART_RESTARTBLOCK: |
704 | case -ERESTARTNOHAND: | |
705 | regs->ax = -EINTR; | |
706 | break; | |
707 | ||
708 | case -ERESTARTSYS: | |
235b8022 | 709 | if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { |
65ea5b03 | 710 | regs->ax = -EINTR; |
1da177e4 | 711 | break; |
ac66f3fd HH |
712 | } |
713 | /* fallthrough */ | |
714 | case -ERESTARTNOINTR: | |
715 | regs->ax = regs->orig_ax; | |
716 | regs->ip -= 2; | |
717 | break; | |
1da177e4 LT |
718 | } |
719 | } | |
720 | ||
721 | /* | |
fd0f86b6 ON |
722 | * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now |
723 | * so that register information in the sigcontext is correct and | |
724 | * then notify the tracer before entering the signal handler. | |
1da177e4 | 725 | */ |
fd0f86b6 ON |
726 | stepping = test_thread_flag(TIF_SINGLESTEP); |
727 | if (stepping) | |
728 | user_disable_single_step(current); | |
1da177e4 | 729 | |
235b8022 AV |
730 | failed = (setup_rt_frame(ksig, regs) < 0); |
731 | if (!failed) { | |
732 | /* | |
733 | * Clear the direction flag as per the ABI for function entry. | |
ddd40da4 | 734 | * |
24cda109 JO |
735 | * Clear RF when entering the signal handler, because |
736 | * it might disable possible debug exception from the | |
737 | * signal handler. | |
ddd40da4 | 738 | * |
fd0f86b6 ON |
739 | * Clear TF for the case when it wasn't set by debugger to |
740 | * avoid the recursive send_sigtrap() in SIGTRAP handler. | |
235b8022 | 741 | */ |
ddd40da4 | 742 | regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); |
66463db4 ON |
743 | /* |
744 | * Ensure the signal handler starts with the new fpu state. | |
745 | */ | |
2722146e | 746 | fpu__clear(fpu); |
a610d6e6 | 747 | } |
fd0f86b6 | 748 | signal_setup_done(failed, ksig, stepping); |
1da177e4 LT |
749 | } |
750 | ||
22eab110 DL |
751 | static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs) |
752 | { | |
609c19a3 AL |
753 | /* |
754 | * This function is fundamentally broken as currently | |
755 | * implemented. | |
756 | * | |
757 | * The idea is that we want to trigger a call to the | |
758 | * restart_block() syscall and that we want in_ia32_syscall(), | |
759 | * in_x32_syscall(), etc. to match whatever they were in the | |
760 | * syscall being restarted. We assume that the syscall | |
761 | * instruction at (regs->ip - 2) matches whatever syscall | |
762 | * instruction we used to enter in the first place. | |
763 | * | |
764 | * The problem is that we can get here when ptrace pokes | |
765 | * syscall-like values into regs even if we're not in a syscall | |
766 | * at all. | |
767 | * | |
768 | * For now, we maintain historical behavior and guess based on | |
769 | * stored state. We could do better by saving the actual | |
770 | * syscall arch in restart_block or (with caveats on x32) by | |
771 | * checking if regs->ip points to 'int $0x80'. The current | |
772 | * behavior is incorrect if a tracer has a different bitness | |
773 | * than the tracee. | |
774 | */ | |
775 | #ifdef CONFIG_IA32_EMULATION | |
37a8f7c3 | 776 | if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED)) |
95d97adb DL |
777 | return __NR_ia32_restart_syscall; |
778 | #endif | |
779 | #ifdef CONFIG_X86_X32_ABI | |
780 | return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT); | |
781 | #else | |
22eab110 | 782 | return __NR_restart_syscall; |
95d97adb | 783 | #endif |
22eab110 | 784 | } |
57917752 | 785 | |
1da177e4 LT |
786 | /* |
787 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
788 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
789 | * mistake. | |
790 | */ | |
1f484aa6 | 791 | void do_signal(struct pt_regs *regs) |
1da177e4 | 792 | { |
235b8022 | 793 | struct ksignal ksig; |
1da177e4 | 794 | |
235b8022 | 795 | if (get_signal(&ksig)) { |
7e907f48 | 796 | /* Whee! Actually deliver the signal. */ |
235b8022 | 797 | handle_signal(&ksig, regs); |
283828f3 | 798 | return; |
1da177e4 LT |
799 | } |
800 | ||
1da177e4 | 801 | /* Did we come from a system call? */ |
bb57925f | 802 | if (syscall_get_nr(current, regs) >= 0) { |
1da177e4 | 803 | /* Restart the system call - no handlers present */ |
bb57925f | 804 | switch (syscall_get_error(current, regs)) { |
283828f3 DH |
805 | case -ERESTARTNOHAND: |
806 | case -ERESTARTSYS: | |
807 | case -ERESTARTNOINTR: | |
65ea5b03 PA |
808 | regs->ax = regs->orig_ax; |
809 | regs->ip -= 2; | |
283828f3 DH |
810 | break; |
811 | ||
812 | case -ERESTART_RESTARTBLOCK: | |
22eab110 | 813 | regs->ax = get_nr_restart_syscall(regs); |
65ea5b03 | 814 | regs->ip -= 2; |
283828f3 | 815 | break; |
1da177e4 LT |
816 | } |
817 | } | |
283828f3 | 818 | |
ac66f3fd HH |
819 | /* |
820 | * If there's no signal to deliver, we just put the saved sigmask | |
821 | * back. | |
822 | */ | |
51a7b448 | 823 | restore_saved_sigmask(); |
1da177e4 LT |
824 | } |
825 | ||
72fa50f4 HS |
826 | void signal_fault(struct pt_regs *regs, void __user *frame, char *where) |
827 | { | |
828 | struct task_struct *me = current; | |
829 | ||
830 | if (show_unhandled_signals && printk_ratelimit()) { | |
ae417bb4 | 831 | printk("%s" |
72fa50f4 | 832 | "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", |
ae417bb4 | 833 | task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, |
72fa50f4 HS |
834 | me->comm, me->pid, where, frame, |
835 | regs->ip, regs->sp, regs->orig_ax); | |
1c99a687 | 836 | print_vma_addr(KERN_CONT " in ", regs->ip); |
c767a54b | 837 | pr_cont("\n"); |
72fa50f4 HS |
838 | } |
839 | ||
3cf5d076 | 840 | force_sig(SIGSEGV); |
72fa50f4 | 841 | } |
c5a37394 PA |
842 | |
843 | #ifdef CONFIG_X86_X32_ABI | |
3fe26fa3 | 844 | asmlinkage long sys32_x32_rt_sigreturn(void) |
c5a37394 | 845 | { |
3fe26fa3 | 846 | struct pt_regs *regs = current_pt_regs(); |
c5a37394 PA |
847 | struct rt_sigframe_x32 __user *frame; |
848 | sigset_t set; | |
6c25da5a | 849 | unsigned long uc_flags; |
c5a37394 PA |
850 | |
851 | frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); | |
852 | ||
96d4f267 | 853 | if (!access_ok(frame, sizeof(*frame))) |
c5a37394 | 854 | goto badframe; |
71c3313a | 855 | if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask)) |
c5a37394 | 856 | goto badframe; |
6c25da5a AL |
857 | if (__get_user(uc_flags, &frame->uc.uc_flags)) |
858 | goto badframe; | |
c5a37394 | 859 | |
c5a37394 PA |
860 | set_current_blocked(&set); |
861 | ||
6c25da5a | 862 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
c5a37394 PA |
863 | goto badframe; |
864 | ||
90268439 | 865 | if (compat_restore_altstack(&frame->uc.uc_stack)) |
c5a37394 PA |
866 | goto badframe; |
867 | ||
6a3713f0 | 868 | return regs->ax; |
c5a37394 PA |
869 | |
870 | badframe: | |
871 | signal_fault(regs, frame, "x32 rt_sigreturn"); | |
872 | return 0; | |
873 | } | |
874 | #endif |