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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 | ||
b00d8f8f AV |
143 | static __always_inline int |
144 | __unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, | |
85139422 | 145 | struct pt_regs *regs, unsigned long mask) |
2601657d | 146 | { |
98e3d45e | 147 | #ifdef CONFIG_X86_32 |
9f855c08 AV |
148 | unsafe_put_user(get_user_gs(regs), |
149 | (unsigned int __user *)&sc->gs, Efault); | |
150 | unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault); | |
151 | unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault); | |
152 | unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault); | |
2601657d HS |
153 | #endif /* CONFIG_X86_32 */ |
154 | ||
9f855c08 AV |
155 | unsafe_put_user(regs->di, &sc->di, Efault); |
156 | unsafe_put_user(regs->si, &sc->si, Efault); | |
157 | unsafe_put_user(regs->bp, &sc->bp, Efault); | |
158 | unsafe_put_user(regs->sp, &sc->sp, Efault); | |
159 | unsafe_put_user(regs->bx, &sc->bx, Efault); | |
160 | unsafe_put_user(regs->dx, &sc->dx, Efault); | |
161 | unsafe_put_user(regs->cx, &sc->cx, Efault); | |
162 | unsafe_put_user(regs->ax, &sc->ax, Efault); | |
2601657d | 163 | #ifdef CONFIG_X86_64 |
9f855c08 AV |
164 | unsafe_put_user(regs->r8, &sc->r8, Efault); |
165 | unsafe_put_user(regs->r9, &sc->r9, Efault); | |
166 | unsafe_put_user(regs->r10, &sc->r10, Efault); | |
167 | unsafe_put_user(regs->r11, &sc->r11, Efault); | |
168 | unsafe_put_user(regs->r12, &sc->r12, Efault); | |
169 | unsafe_put_user(regs->r13, &sc->r13, Efault); | |
170 | unsafe_put_user(regs->r14, &sc->r14, Efault); | |
171 | unsafe_put_user(regs->r15, &sc->r15, Efault); | |
2601657d HS |
172 | #endif /* CONFIG_X86_64 */ |
173 | ||
9f855c08 AV |
174 | unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault); |
175 | unsafe_put_user(current->thread.error_code, &sc->err, Efault); | |
176 | unsafe_put_user(regs->ip, &sc->ip, Efault); | |
2601657d | 177 | #ifdef CONFIG_X86_32 |
9f855c08 AV |
178 | unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault); |
179 | unsafe_put_user(regs->flags, &sc->flags, Efault); | |
180 | unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault); | |
181 | unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault); | |
2601657d | 182 | #else /* !CONFIG_X86_32 */ |
9f855c08 AV |
183 | unsafe_put_user(regs->flags, &sc->flags, Efault); |
184 | unsafe_put_user(regs->cs, &sc->cs, Efault); | |
185 | unsafe_put_user(0, &sc->gs, Efault); | |
186 | unsafe_put_user(0, &sc->fs, Efault); | |
187 | unsafe_put_user(regs->ss, &sc->ss, Efault); | |
2601657d HS |
188 | #endif /* CONFIG_X86_32 */ |
189 | ||
9f855c08 | 190 | unsafe_put_user(fpstate, (unsigned long __user *)&sc->fpstate, Efault); |
2601657d | 191 | |
9f855c08 AV |
192 | /* non-iBCS2 extensions.. */ |
193 | unsafe_put_user(mask, &sc->oldmask, Efault); | |
194 | unsafe_put_user(current->thread.cr2, &sc->cr2, Efault); | |
9f855c08 AV |
195 | return 0; |
196 | Efault: | |
9f855c08 | 197 | return -EFAULT; |
2601657d HS |
198 | } |
199 | ||
b00d8f8f AV |
200 | #define unsafe_put_sigcontext(sc, fp, regs, set, label) \ |
201 | do { \ | |
202 | if (__unsafe_setup_sigcontext(sc, fp, regs, set->sig[0])) \ | |
203 | goto label; \ | |
204 | } while(0); | |
205 | ||
1da177e4 | 206 | /* |
bfeb91a9 | 207 | * Set up a signal frame. |
1da177e4 | 208 | */ |
1da177e4 LT |
209 | |
210 | /* | |
211 | * Determine which stack to use.. | |
212 | */ | |
1fae0279 HS |
213 | static unsigned long align_sigframe(unsigned long sp) |
214 | { | |
215 | #ifdef CONFIG_X86_32 | |
216 | /* | |
217 | * Align the stack pointer according to the i386 ABI, | |
218 | * i.e. so that on function entry ((sp + 4) & 15) == 0. | |
219 | */ | |
220 | sp = ((sp + 4) & -16ul) - 4; | |
221 | #else /* !CONFIG_X86_32 */ | |
222 | sp = round_down(sp, 16) - 8; | |
223 | #endif | |
224 | return sp; | |
225 | } | |
226 | ||
dae0f305 | 227 | static void __user * |
3c1c7f10 | 228 | get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, |
144b0712 | 229 | void __user **fpstate) |
1da177e4 | 230 | { |
1da177e4 | 231 | /* Default to using normal stack */ |
72a671ce | 232 | unsigned long math_size = 0; |
75779f05 | 233 | unsigned long sp = regs->sp; |
72a671ce | 234 | unsigned long buf_fx = 0; |
14fc9fbc | 235 | int onsigstack = on_sig_stack(sp); |
2722146e | 236 | int ret; |
75779f05 | 237 | |
75779f05 | 238 | /* redzone */ |
97f2645f | 239 | if (IS_ENABLED(CONFIG_X86_64)) |
050902c0 | 240 | sp -= 128; |
1da177e4 | 241 | |
0b4521e8 SS |
242 | /* This is the X/Open sanctioned signal stack switching. */ |
243 | if (ka->sa.sa_flags & SA_ONSTACK) { | |
244 | if (sas_ss_flags(sp) == 0) | |
245 | sp = current->sas_ss_sp + current->sas_ss_size; | |
97f2645f | 246 | } else if (IS_ENABLED(CONFIG_X86_32) && |
0b4521e8 | 247 | !onsigstack && |
99504819 | 248 | regs->ss != __USER_DS && |
0b4521e8 SS |
249 | !(ka->sa.sa_flags & SA_RESTORER) && |
250 | ka->sa.sa_restorer) { | |
251 | /* This is the legacy signal stack switching. */ | |
252 | sp = (unsigned long) ka->sa.sa_restorer; | |
1da177e4 LT |
253 | } |
254 | ||
2722146e SAS |
255 | sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32), |
256 | &buf_fx, &math_size); | |
257 | *fpstate = (void __user *)sp; | |
3c1c7f10 | 258 | |
14fc9fbc HS |
259 | sp = align_sigframe(sp - frame_size); |
260 | ||
261 | /* | |
262 | * If we are on the alternate signal stack and would overflow it, don't. | |
263 | * Return an always-bogus address instead so we will die with SIGSEGV. | |
264 | */ | |
265 | if (onsigstack && !likely(on_sig_stack(sp))) | |
266 | return (void __user *)-1L; | |
267 | ||
72a671ce | 268 | /* save i387 and extended state */ |
2722146e SAS |
269 | ret = copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size); |
270 | if (ret < 0) | |
14fc9fbc HS |
271 | return (void __user *)-1L; |
272 | ||
273 | return (void __user *)sp; | |
1da177e4 LT |
274 | } |
275 | ||
75779f05 HS |
276 | #ifdef CONFIG_X86_32 |
277 | static const struct { | |
278 | u16 poplmovl; | |
279 | u32 val; | |
280 | u16 int80; | |
281 | } __attribute__((packed)) retcode = { | |
282 | 0xb858, /* popl %eax; movl $..., %eax */ | |
283 | __NR_sigreturn, | |
284 | 0x80cd, /* int $0x80 */ | |
285 | }; | |
286 | ||
287 | static const struct { | |
288 | u8 movl; | |
289 | u32 val; | |
290 | u16 int80; | |
291 | u8 pad; | |
292 | } __attribute__((packed)) rt_retcode = { | |
293 | 0xb8, /* movl $..., %eax */ | |
294 | __NR_rt_sigreturn, | |
295 | 0x80cd, /* int $0x80 */ | |
296 | 0 | |
297 | }; | |
298 | ||
7e907f48 | 299 | static int |
235b8022 | 300 | __setup_frame(int sig, struct ksignal *ksig, sigset_t *set, |
1d13024e | 301 | struct pt_regs *regs) |
1da177e4 | 302 | { |
1da177e4 | 303 | struct sigframe __user *frame; |
7e907f48 | 304 | void __user *restorer; |
b00d8f8f | 305 | void __user *fp = NULL; |
1da177e4 | 306 | |
b00d8f8f | 307 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp); |
1da177e4 | 308 | |
5c1f1780 | 309 | if (!user_access_begin(frame, sizeof(*frame))) |
3d0aedd9 | 310 | return -EFAULT; |
1da177e4 | 311 | |
5c1f1780 | 312 | unsafe_put_user(sig, &frame->sig, Efault); |
b00d8f8f | 313 | unsafe_put_sigcontext(&frame->sc, fp, regs, set, Efault); |
5c1f1780 | 314 | unsafe_put_user(set->sig[1], &frame->extramask[0], Efault); |
1a3e4ca4 | 315 | if (current->mm->context.vdso) |
6f121e54 | 316 | restorer = current->mm->context.vdso + |
0a6d1fa0 | 317 | vdso_image_32.sym___kernel_sigreturn; |
9fbbd4dd | 318 | else |
ade1af77 | 319 | restorer = &frame->retcode; |
235b8022 AV |
320 | if (ksig->ka.sa.sa_flags & SA_RESTORER) |
321 | restorer = ksig->ka.sa.sa_restorer; | |
1da177e4 LT |
322 | |
323 | /* Set up to return from userspace. */ | |
5c1f1780 | 324 | unsafe_put_user(restorer, &frame->pretcode, Efault); |
7e907f48 | 325 | |
1da177e4 | 326 | /* |
7e907f48 | 327 | * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 |
1da177e4 LT |
328 | * |
329 | * WE DO NOT USE IT ANY MORE! It's only left here for historical | |
330 | * reasons and because gdb uses it as a signature to notice | |
331 | * signal handler stack frames. | |
332 | */ | |
5c1f1780 AV |
333 | unsafe_put_user(*((u64 *)&retcode), (u64 *)frame->retcode, Efault); |
334 | user_access_end(); | |
1da177e4 LT |
335 | |
336 | /* Set up registers for signal handler */ | |
7e907f48 | 337 | regs->sp = (unsigned long)frame; |
235b8022 | 338 | regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
7e907f48 | 339 | regs->ax = (unsigned long)sig; |
92bc2056 HH |
340 | regs->dx = 0; |
341 | regs->cx = 0; | |
1da177e4 | 342 | |
65ea5b03 PA |
343 | regs->ds = __USER_DS; |
344 | regs->es = __USER_DS; | |
345 | regs->ss = __USER_DS; | |
346 | regs->cs = __USER_CS; | |
1da177e4 | 347 | |
283828f3 | 348 | return 0; |
b00d8f8f AV |
349 | |
350 | Efault: | |
351 | user_access_end(); | |
352 | return -EFAULT; | |
1da177e4 LT |
353 | } |
354 | ||
235b8022 | 355 | static int __setup_rt_frame(int sig, struct ksignal *ksig, |
1d13024e | 356 | sigset_t *set, struct pt_regs *regs) |
1da177e4 | 357 | { |
1da177e4 | 358 | struct rt_sigframe __user *frame; |
7e907f48 | 359 | void __user *restorer; |
b00d8f8f | 360 | void __user *fp = NULL; |
1da177e4 | 361 | |
b00d8f8f | 362 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp); |
1da177e4 | 363 | |
119cd59f | 364 | if (!user_access_begin(frame, sizeof(*frame))) |
3d0aedd9 | 365 | return -EFAULT; |
1da177e4 | 366 | |
119cd59f AV |
367 | unsafe_put_user(sig, &frame->sig, Efault); |
368 | unsafe_put_user(&frame->info, &frame->pinfo, Efault); | |
369 | unsafe_put_user(&frame->uc, &frame->puc, Efault); | |
98e3d45e | 370 | |
119cd59f AV |
371 | /* Create the ucontext. */ |
372 | if (static_cpu_has(X86_FEATURE_XSAVE)) | |
373 | unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault); | |
374 | else | |
375 | unsafe_put_user(0, &frame->uc.uc_flags, Efault); | |
376 | unsafe_put_user(0, &frame->uc.uc_link, Efault); | |
377 | unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); | |
98e3d45e | 378 | |
119cd59f AV |
379 | /* Set up to return from userspace. */ |
380 | restorer = current->mm->context.vdso + | |
381 | vdso_image_32.sym___kernel_rt_sigreturn; | |
382 | if (ksig->ka.sa.sa_flags & SA_RESTORER) | |
383 | restorer = ksig->ka.sa.sa_restorer; | |
384 | unsafe_put_user(restorer, &frame->pretcode, Efault); | |
385 | ||
386 | /* | |
387 | * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 | |
388 | * | |
389 | * WE DO NOT USE IT ANY MORE! It's only left here for historical | |
390 | * reasons and because gdb uses it as a signature to notice | |
391 | * signal handler stack frames. | |
392 | */ | |
393 | unsafe_put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode, Efault); | |
b00d8f8f | 394 | unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault); |
ead8e4e7 AV |
395 | unsafe_put_user(*(__u64 *)set, |
396 | (__u64 __user *)&frame->uc.uc_sigmask, Efault); | |
119cd59f | 397 | user_access_end(); |
49b8c695 | 398 | |
ead8e4e7 | 399 | if (copy_siginfo_to_user(&frame->info, &ksig->info)) |
3d0aedd9 | 400 | return -EFAULT; |
1da177e4 LT |
401 | |
402 | /* Set up registers for signal handler */ | |
7e907f48 | 403 | regs->sp = (unsigned long)frame; |
235b8022 | 404 | regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
13ad7725 | 405 | regs->ax = (unsigned long)sig; |
7e907f48 IM |
406 | regs->dx = (unsigned long)&frame->info; |
407 | regs->cx = (unsigned long)&frame->uc; | |
1da177e4 | 408 | |
65ea5b03 PA |
409 | regs->ds = __USER_DS; |
410 | regs->es = __USER_DS; | |
411 | regs->ss = __USER_DS; | |
412 | regs->cs = __USER_CS; | |
1da177e4 | 413 | |
283828f3 | 414 | return 0; |
119cd59f AV |
415 | Efault: |
416 | user_access_end(); | |
417 | return -EFAULT; | |
1da177e4 | 418 | } |
bfeb91a9 | 419 | #else /* !CONFIG_X86_32 */ |
6c25da5a AL |
420 | static unsigned long frame_uc_flags(struct pt_regs *regs) |
421 | { | |
422 | unsigned long flags; | |
423 | ||
d366bf7e | 424 | if (boot_cpu_has(X86_FEATURE_XSAVE)) |
6c25da5a AL |
425 | flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS; |
426 | else | |
427 | flags = UC_SIGCONTEXT_SS; | |
428 | ||
429 | if (likely(user_64bit_mode(regs))) | |
430 | flags |= UC_STRICT_RESTORE_SS; | |
431 | ||
432 | return flags; | |
433 | } | |
434 | ||
235b8022 | 435 | static int __setup_rt_frame(int sig, struct ksignal *ksig, |
bfeb91a9 HS |
436 | sigset_t *set, struct pt_regs *regs) |
437 | { | |
438 | struct rt_sigframe __user *frame; | |
439 | void __user *fp = NULL; | |
88e47182 | 440 | unsigned long uc_flags; |
bfeb91a9 | 441 | |
119cd59f AV |
442 | /* x86-64 should always use SA_RESTORER. */ |
443 | if (!(ksig->ka.sa.sa_flags & SA_RESTORER)) | |
444 | return -EFAULT; | |
445 | ||
235b8022 | 446 | frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp); |
88e47182 | 447 | uc_flags = frame_uc_flags(regs); |
ead8e4e7 | 448 | |
119cd59f AV |
449 | if (!user_access_begin(frame, sizeof(*frame))) |
450 | return -EFAULT; | |
88e47182 | 451 | |
119cd59f AV |
452 | /* Create the ucontext. */ |
453 | unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault); | |
454 | unsafe_put_user(0, &frame->uc.uc_link, Efault); | |
455 | unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); | |
456 | ||
457 | /* Set up to return from userspace. If provided, use a stub | |
458 | already in userspace. */ | |
459 | unsafe_put_user(ksig->ka.sa.sa_restorer, &frame->pretcode, Efault); | |
b00d8f8f | 460 | unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault); |
ead8e4e7 | 461 | unsafe_put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0], Efault); |
119cd59f | 462 | user_access_end(); |
5e88353d | 463 | |
ead8e4e7 AV |
464 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
465 | if (copy_siginfo_to_user(&frame->info, &ksig->info)) | |
466 | return -EFAULT; | |
467 | } | |
bfeb91a9 HS |
468 | |
469 | /* Set up registers for signal handler */ | |
470 | regs->di = sig; | |
471 | /* In case the signal handler was declared without prototypes */ | |
472 | regs->ax = 0; | |
473 | ||
474 | /* This also works for non SA_SIGINFO handlers because they expect the | |
475 | next argument after the signal number on the stack. */ | |
476 | regs->si = (unsigned long)&frame->info; | |
477 | regs->dx = (unsigned long)&frame->uc; | |
235b8022 | 478 | regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
bfeb91a9 HS |
479 | |
480 | regs->sp = (unsigned long)frame; | |
481 | ||
8ff5bd2e AL |
482 | /* |
483 | * Set up the CS and SS registers to run signal handlers in | |
484 | * 64-bit mode, even if the handler happens to be interrupting | |
485 | * 32-bit or 16-bit code. | |
486 | * | |
487 | * SS is subtle. In 64-bit mode, we don't need any particular | |
488 | * SS descriptor, but we do need SS to be valid. It's possible | |
489 | * that the old SS is entirely bogus -- this can happen if the | |
490 | * signal we're trying to deliver is #GP or #SS caused by a bad | |
491 | * SS value. We also have a compatbility issue here: DOSEMU | |
492 | * relies on the contents of the SS register indicating the | |
493 | * SS value at the time of the signal, even though that code in | |
494 | * DOSEMU predates sigreturn's ability to restore SS. (DOSEMU | |
495 | * avoids relying on sigreturn to restore SS; instead it uses | |
496 | * a trampoline.) So we do our best: if the old SS was valid, | |
497 | * we keep it. Otherwise we replace it. | |
498 | */ | |
bfeb91a9 HS |
499 | regs->cs = __USER_CS; |
500 | ||
8ff5bd2e AL |
501 | if (unlikely(regs->ss != __USER_DS)) |
502 | force_valid_ss(regs); | |
503 | ||
bfeb91a9 | 504 | return 0; |
119cd59f AV |
505 | |
506 | Efault: | |
507 | user_access_end(); | |
508 | return -EFAULT; | |
bfeb91a9 HS |
509 | } |
510 | #endif /* CONFIG_X86_32 */ | |
511 | ||
235b8022 AV |
512 | static int x32_setup_rt_frame(struct ksignal *ksig, |
513 | compat_sigset_t *set, | |
050902c0 SS |
514 | struct pt_regs *regs) |
515 | { | |
516 | #ifdef CONFIG_X86_X32_ABI | |
517 | struct rt_sigframe_x32 __user *frame; | |
88e47182 | 518 | unsigned long uc_flags; |
050902c0 | 519 | void __user *restorer; |
b00d8f8f | 520 | void __user *fp = NULL; |
050902c0 | 521 | |
39f16c1c AV |
522 | if (!(ksig->ka.sa.sa_flags & SA_RESTORER)) |
523 | return -EFAULT; | |
524 | ||
b00d8f8f | 525 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp); |
050902c0 | 526 | |
88e47182 PZ |
527 | uc_flags = frame_uc_flags(regs); |
528 | ||
39f16c1c AV |
529 | if (!user_access_begin(frame, sizeof(*frame))) |
530 | return -EFAULT; | |
050902c0 | 531 | |
39f16c1c AV |
532 | /* Create the ucontext. */ |
533 | unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault); | |
534 | unsafe_put_user(0, &frame->uc.uc_link, Efault); | |
535 | unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); | |
536 | unsafe_put_user(0, &frame->uc.uc__pad0, Efault); | |
537 | restorer = ksig->ka.sa.sa_restorer; | |
538 | unsafe_put_user(restorer, (unsigned long __user *)&frame->pretcode, Efault); | |
b00d8f8f | 539 | unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault); |
791612e9 | 540 | unsafe_put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask, Efault); |
39f16c1c | 541 | user_access_end(); |
49b8c695 | 542 | |
791612e9 AV |
543 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
544 | if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true)) | |
545 | return -EFAULT; | |
546 | } | |
050902c0 SS |
547 | |
548 | /* Set up registers for signal handler */ | |
549 | regs->sp = (unsigned long) frame; | |
235b8022 | 550 | regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
050902c0 SS |
551 | |
552 | /* We use the x32 calling convention here... */ | |
235b8022 | 553 | regs->di = ksig->sig; |
050902c0 SS |
554 | regs->si = (unsigned long) &frame->info; |
555 | regs->dx = (unsigned long) &frame->uc; | |
556 | ||
557 | loadsegment(ds, __USER_DS); | |
558 | loadsegment(es, __USER_DS); | |
559 | ||
560 | regs->cs = __USER_CS; | |
561 | regs->ss = __USER_DS; | |
562 | #endif /* CONFIG_X86_X32_ABI */ | |
563 | ||
564 | return 0; | |
39f16c1c AV |
565 | #ifdef CONFIG_X86_X32_ABI |
566 | Efault: | |
567 | user_access_end(); | |
568 | return -EFAULT; | |
569 | #endif | |
050902c0 SS |
570 | } |
571 | ||
bfeb91a9 HS |
572 | /* |
573 | * Do a signal return; undo the signal stack. | |
574 | */ | |
e5fa2d06 | 575 | #ifdef CONFIG_X86_32 |
4c8ca51a | 576 | SYSCALL_DEFINE0(sigreturn) |
bfeb91a9 | 577 | { |
3fe26fa3 | 578 | struct pt_regs *regs = current_pt_regs(); |
bfeb91a9 | 579 | struct sigframe __user *frame; |
bfeb91a9 HS |
580 | sigset_t set; |
581 | ||
bfeb91a9 HS |
582 | frame = (struct sigframe __user *)(regs->sp - 8); |
583 | ||
96d4f267 | 584 | if (!access_ok(frame, sizeof(*frame))) |
bfeb91a9 | 585 | goto badframe; |
71c3313a AV |
586 | if (__get_user(set.sig[0], &frame->sc.oldmask) || |
587 | __get_user(set.sig[1], &frame->extramask[0])) | |
bfeb91a9 HS |
588 | goto badframe; |
589 | ||
3982294b | 590 | set_current_blocked(&set); |
bfeb91a9 | 591 | |
6c25da5a AL |
592 | /* |
593 | * x86_32 has no uc_flags bits relevant to restore_sigcontext. | |
594 | * Save a few cycles by skipping the __get_user. | |
595 | */ | |
596 | if (restore_sigcontext(regs, &frame->sc, 0)) | |
bfeb91a9 | 597 | goto badframe; |
6a3713f0 | 598 | return regs->ax; |
bfeb91a9 HS |
599 | |
600 | badframe: | |
ae417bb4 | 601 | signal_fault(regs, frame, "sigreturn"); |
bfeb91a9 HS |
602 | |
603 | return 0; | |
604 | } | |
e5fa2d06 | 605 | #endif /* CONFIG_X86_32 */ |
bfeb91a9 | 606 | |
4c8ca51a | 607 | SYSCALL_DEFINE0(rt_sigreturn) |
bfeb91a9 | 608 | { |
3fe26fa3 | 609 | struct pt_regs *regs = current_pt_regs(); |
bfeb91a9 | 610 | struct rt_sigframe __user *frame; |
bfeb91a9 | 611 | sigset_t set; |
6c25da5a | 612 | unsigned long uc_flags; |
bfeb91a9 HS |
613 | |
614 | frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long)); | |
96d4f267 | 615 | if (!access_ok(frame, sizeof(*frame))) |
bfeb91a9 | 616 | goto badframe; |
71c3313a | 617 | if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask)) |
bfeb91a9 | 618 | goto badframe; |
6c25da5a AL |
619 | if (__get_user(uc_flags, &frame->uc.uc_flags)) |
620 | goto badframe; | |
bfeb91a9 | 621 | |
e9bd3f0f | 622 | set_current_blocked(&set); |
bfeb91a9 | 623 | |
6c25da5a | 624 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
bfeb91a9 HS |
625 | goto badframe; |
626 | ||
c40702c4 | 627 | if (restore_altstack(&frame->uc.uc_stack)) |
bfeb91a9 HS |
628 | goto badframe; |
629 | ||
6a3713f0 | 630 | return regs->ax; |
bfeb91a9 HS |
631 | |
632 | badframe: | |
633 | signal_fault(regs, frame, "rt_sigreturn"); | |
634 | return 0; | |
635 | } | |
636 | ||
68463510 | 637 | static inline int is_ia32_compat_frame(struct ksignal *ksig) |
05012c13 | 638 | { |
97f2645f | 639 | return IS_ENABLED(CONFIG_IA32_EMULATION) && |
68463510 | 640 | ksig->ka.sa.sa_flags & SA_IA32_ABI; |
05012c13 IM |
641 | } |
642 | ||
68463510 | 643 | static inline int is_ia32_frame(struct ksignal *ksig) |
05012c13 | 644 | { |
68463510 | 645 | return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig); |
05012c13 IM |
646 | } |
647 | ||
68463510 | 648 | static inline int is_x32_frame(struct ksignal *ksig) |
05012c13 | 649 | { |
68463510 DS |
650 | return IS_ENABLED(CONFIG_X86_X32_ABI) && |
651 | ksig->ka.sa.sa_flags & SA_X32_ABI; | |
05012c13 IM |
652 | } |
653 | ||
1d13024e | 654 | static int |
235b8022 | 655 | setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) |
1d13024e | 656 | { |
3050a35f | 657 | int usig = ksig->sig; |
b7f9a11a | 658 | sigset_t *set = sigmask_to_save(); |
050902c0 | 659 | compat_sigset_t *cset = (compat_sigset_t *) set; |
1d13024e | 660 | |
bff9504b | 661 | /* Perform fixup for the pre-signal frame. */ |
784e0300 | 662 | rseq_signal_deliver(ksig, regs); |
d6761b8f | 663 | |
1d13024e | 664 | /* Set up the stack frame */ |
68463510 | 665 | if (is_ia32_frame(ksig)) { |
235b8022 AV |
666 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
667 | return ia32_setup_rt_frame(usig, ksig, cset, regs); | |
455edbc4 | 668 | else |
235b8022 | 669 | return ia32_setup_frame(usig, ksig, cset, regs); |
68463510 | 670 | } else if (is_x32_frame(ksig)) { |
235b8022 | 671 | return x32_setup_rt_frame(ksig, cset, regs); |
c5a37394 | 672 | } else { |
235b8022 | 673 | return __setup_rt_frame(ksig->sig, ksig, set, regs); |
c5a37394 | 674 | } |
1d13024e HS |
675 | } |
676 | ||
a610d6e6 | 677 | static void |
235b8022 | 678 | handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
1da177e4 | 679 | { |
fd0f86b6 | 680 | bool stepping, failed; |
c5bedc68 | 681 | struct fpu *fpu = ¤t->thread.fpu; |
fd0f86b6 | 682 | |
5ed92a8a BG |
683 | if (v8086_mode(regs)) |
684 | save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL); | |
685 | ||
1da177e4 | 686 | /* Are we from a system call? */ |
bb57925f | 687 | if (syscall_get_nr(current, regs) >= 0) { |
1da177e4 | 688 | /* If so, check system call restarting.. */ |
bb57925f | 689 | switch (syscall_get_error(current, regs)) { |
ac66f3fd HH |
690 | case -ERESTART_RESTARTBLOCK: |
691 | case -ERESTARTNOHAND: | |
692 | regs->ax = -EINTR; | |
693 | break; | |
694 | ||
695 | case -ERESTARTSYS: | |
235b8022 | 696 | if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { |
65ea5b03 | 697 | regs->ax = -EINTR; |
1da177e4 | 698 | break; |
ac66f3fd HH |
699 | } |
700 | /* fallthrough */ | |
701 | case -ERESTARTNOINTR: | |
702 | regs->ax = regs->orig_ax; | |
703 | regs->ip -= 2; | |
704 | break; | |
1da177e4 LT |
705 | } |
706 | } | |
707 | ||
708 | /* | |
fd0f86b6 ON |
709 | * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now |
710 | * so that register information in the sigcontext is correct and | |
711 | * then notify the tracer before entering the signal handler. | |
1da177e4 | 712 | */ |
fd0f86b6 ON |
713 | stepping = test_thread_flag(TIF_SINGLESTEP); |
714 | if (stepping) | |
715 | user_disable_single_step(current); | |
1da177e4 | 716 | |
235b8022 AV |
717 | failed = (setup_rt_frame(ksig, regs) < 0); |
718 | if (!failed) { | |
719 | /* | |
720 | * Clear the direction flag as per the ABI for function entry. | |
ddd40da4 | 721 | * |
24cda109 JO |
722 | * Clear RF when entering the signal handler, because |
723 | * it might disable possible debug exception from the | |
724 | * signal handler. | |
ddd40da4 | 725 | * |
fd0f86b6 ON |
726 | * Clear TF for the case when it wasn't set by debugger to |
727 | * avoid the recursive send_sigtrap() in SIGTRAP handler. | |
235b8022 | 728 | */ |
ddd40da4 | 729 | regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); |
66463db4 ON |
730 | /* |
731 | * Ensure the signal handler starts with the new fpu state. | |
732 | */ | |
2722146e | 733 | fpu__clear(fpu); |
a610d6e6 | 734 | } |
fd0f86b6 | 735 | signal_setup_done(failed, ksig, stepping); |
1da177e4 LT |
736 | } |
737 | ||
22eab110 DL |
738 | static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs) |
739 | { | |
609c19a3 AL |
740 | /* |
741 | * This function is fundamentally broken as currently | |
742 | * implemented. | |
743 | * | |
744 | * The idea is that we want to trigger a call to the | |
745 | * restart_block() syscall and that we want in_ia32_syscall(), | |
746 | * in_x32_syscall(), etc. to match whatever they were in the | |
747 | * syscall being restarted. We assume that the syscall | |
748 | * instruction at (regs->ip - 2) matches whatever syscall | |
749 | * instruction we used to enter in the first place. | |
750 | * | |
751 | * The problem is that we can get here when ptrace pokes | |
752 | * syscall-like values into regs even if we're not in a syscall | |
753 | * at all. | |
754 | * | |
755 | * For now, we maintain historical behavior and guess based on | |
756 | * stored state. We could do better by saving the actual | |
757 | * syscall arch in restart_block or (with caveats on x32) by | |
758 | * checking if regs->ip points to 'int $0x80'. The current | |
759 | * behavior is incorrect if a tracer has a different bitness | |
760 | * than the tracee. | |
761 | */ | |
762 | #ifdef CONFIG_IA32_EMULATION | |
37a8f7c3 | 763 | if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED)) |
95d97adb DL |
764 | return __NR_ia32_restart_syscall; |
765 | #endif | |
766 | #ifdef CONFIG_X86_X32_ABI | |
767 | return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT); | |
768 | #else | |
22eab110 | 769 | return __NR_restart_syscall; |
95d97adb | 770 | #endif |
22eab110 | 771 | } |
57917752 | 772 | |
1da177e4 LT |
773 | /* |
774 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
775 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
776 | * mistake. | |
777 | */ | |
1f484aa6 | 778 | void do_signal(struct pt_regs *regs) |
1da177e4 | 779 | { |
235b8022 | 780 | struct ksignal ksig; |
1da177e4 | 781 | |
235b8022 | 782 | if (get_signal(&ksig)) { |
7e907f48 | 783 | /* Whee! Actually deliver the signal. */ |
235b8022 | 784 | handle_signal(&ksig, regs); |
283828f3 | 785 | return; |
1da177e4 LT |
786 | } |
787 | ||
1da177e4 | 788 | /* Did we come from a system call? */ |
bb57925f | 789 | if (syscall_get_nr(current, regs) >= 0) { |
1da177e4 | 790 | /* Restart the system call - no handlers present */ |
bb57925f | 791 | switch (syscall_get_error(current, regs)) { |
283828f3 DH |
792 | case -ERESTARTNOHAND: |
793 | case -ERESTARTSYS: | |
794 | case -ERESTARTNOINTR: | |
65ea5b03 PA |
795 | regs->ax = regs->orig_ax; |
796 | regs->ip -= 2; | |
283828f3 DH |
797 | break; |
798 | ||
799 | case -ERESTART_RESTARTBLOCK: | |
22eab110 | 800 | regs->ax = get_nr_restart_syscall(regs); |
65ea5b03 | 801 | regs->ip -= 2; |
283828f3 | 802 | break; |
1da177e4 LT |
803 | } |
804 | } | |
283828f3 | 805 | |
ac66f3fd HH |
806 | /* |
807 | * If there's no signal to deliver, we just put the saved sigmask | |
808 | * back. | |
809 | */ | |
51a7b448 | 810 | restore_saved_sigmask(); |
1da177e4 LT |
811 | } |
812 | ||
72fa50f4 HS |
813 | void signal_fault(struct pt_regs *regs, void __user *frame, char *where) |
814 | { | |
815 | struct task_struct *me = current; | |
816 | ||
817 | if (show_unhandled_signals && printk_ratelimit()) { | |
ae417bb4 | 818 | printk("%s" |
72fa50f4 | 819 | "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", |
ae417bb4 | 820 | task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, |
72fa50f4 HS |
821 | me->comm, me->pid, where, frame, |
822 | regs->ip, regs->sp, regs->orig_ax); | |
1c99a687 | 823 | print_vma_addr(KERN_CONT " in ", regs->ip); |
c767a54b | 824 | pr_cont("\n"); |
72fa50f4 HS |
825 | } |
826 | ||
3cf5d076 | 827 | force_sig(SIGSEGV); |
72fa50f4 | 828 | } |
c5a37394 PA |
829 | |
830 | #ifdef CONFIG_X86_X32_ABI | |
3fe26fa3 | 831 | asmlinkage long sys32_x32_rt_sigreturn(void) |
c5a37394 | 832 | { |
3fe26fa3 | 833 | struct pt_regs *regs = current_pt_regs(); |
c5a37394 PA |
834 | struct rt_sigframe_x32 __user *frame; |
835 | sigset_t set; | |
6c25da5a | 836 | unsigned long uc_flags; |
c5a37394 PA |
837 | |
838 | frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); | |
839 | ||
96d4f267 | 840 | if (!access_ok(frame, sizeof(*frame))) |
c5a37394 | 841 | goto badframe; |
71c3313a | 842 | if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask)) |
c5a37394 | 843 | goto badframe; |
6c25da5a AL |
844 | if (__get_user(uc_flags, &frame->uc.uc_flags)) |
845 | goto badframe; | |
c5a37394 | 846 | |
c5a37394 PA |
847 | set_current_blocked(&set); |
848 | ||
6c25da5a | 849 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
c5a37394 PA |
850 | goto badframe; |
851 | ||
90268439 | 852 | if (compat_restore_altstack(&frame->uc.uc_stack)) |
c5a37394 PA |
853 | goto badframe; |
854 | ||
6a3713f0 | 855 | return regs->ax; |
c5a37394 PA |
856 | |
857 | badframe: | |
858 | signal_fault(regs, frame, "x32 rt_sigreturn"); | |
859 | return 0; | |
860 | } | |
861 | #endif |