Commit | Line | Data |
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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> |
167fd210 | 28 | #include <linux/entry-common.h> |
4c8ca51a | 29 | #include <linux/syscalls.h> |
7e907f48 | 30 | |
1da177e4 LT |
31 | #include <asm/processor.h> |
32 | #include <asm/ucontext.h> | |
78f7f1e5 | 33 | #include <asm/fpu/internal.h> |
fcbc99c4 | 34 | #include <asm/fpu/signal.h> |
6c3652ef | 35 | #include <asm/vdso.h> |
4efc0670 | 36 | #include <asm/mce.h> |
f28f0c23 | 37 | #include <asm/sighandling.h> |
ba3e127e | 38 | #include <asm/vm86.h> |
5c9b3a0c HS |
39 | |
40 | #ifdef CONFIG_X86_64 | |
c3b3f524 | 41 | #include <linux/compat.h> |
5c9b3a0c HS |
42 | #include <asm/proto.h> |
43 | #include <asm/ia32_unistd.h> | |
5c9b3a0c HS |
44 | #endif /* CONFIG_X86_64 */ |
45 | ||
bb57925f | 46 | #include <asm/syscall.h> |
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 | ||
b87df659 AV |
206 | #define unsafe_put_sigmask(set, frame, label) \ |
207 | unsafe_put_user(*(__u64 *)(set), \ | |
208 | (__u64 __user *)&(frame)->uc.uc_sigmask, \ | |
209 | label) | |
210 | ||
1da177e4 | 211 | /* |
bfeb91a9 | 212 | * Set up a signal frame. |
1da177e4 | 213 | */ |
1da177e4 LT |
214 | |
215 | /* | |
216 | * Determine which stack to use.. | |
217 | */ | |
1fae0279 HS |
218 | static unsigned long align_sigframe(unsigned long sp) |
219 | { | |
220 | #ifdef CONFIG_X86_32 | |
221 | /* | |
222 | * Align the stack pointer according to the i386 ABI, | |
223 | * i.e. so that on function entry ((sp + 4) & 15) == 0. | |
224 | */ | |
225 | sp = ((sp + 4) & -16ul) - 4; | |
226 | #else /* !CONFIG_X86_32 */ | |
227 | sp = round_down(sp, 16) - 8; | |
228 | #endif | |
229 | return sp; | |
230 | } | |
231 | ||
dae0f305 | 232 | static void __user * |
3c1c7f10 | 233 | get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, |
144b0712 | 234 | void __user **fpstate) |
1da177e4 | 235 | { |
1da177e4 | 236 | /* Default to using normal stack */ |
72a671ce | 237 | unsigned long math_size = 0; |
75779f05 | 238 | unsigned long sp = regs->sp; |
72a671ce | 239 | unsigned long buf_fx = 0; |
14fc9fbc | 240 | int onsigstack = on_sig_stack(sp); |
2722146e | 241 | int ret; |
75779f05 | 242 | |
75779f05 | 243 | /* redzone */ |
97f2645f | 244 | if (IS_ENABLED(CONFIG_X86_64)) |
050902c0 | 245 | sp -= 128; |
1da177e4 | 246 | |
0b4521e8 SS |
247 | /* This is the X/Open sanctioned signal stack switching. */ |
248 | if (ka->sa.sa_flags & SA_ONSTACK) { | |
249 | if (sas_ss_flags(sp) == 0) | |
250 | sp = current->sas_ss_sp + current->sas_ss_size; | |
97f2645f | 251 | } else if (IS_ENABLED(CONFIG_X86_32) && |
0b4521e8 | 252 | !onsigstack && |
99504819 | 253 | regs->ss != __USER_DS && |
0b4521e8 SS |
254 | !(ka->sa.sa_flags & SA_RESTORER) && |
255 | ka->sa.sa_restorer) { | |
256 | /* This is the legacy signal stack switching. */ | |
257 | sp = (unsigned long) ka->sa.sa_restorer; | |
1da177e4 LT |
258 | } |
259 | ||
2722146e SAS |
260 | sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32), |
261 | &buf_fx, &math_size); | |
262 | *fpstate = (void __user *)sp; | |
3c1c7f10 | 263 | |
14fc9fbc HS |
264 | sp = align_sigframe(sp - frame_size); |
265 | ||
266 | /* | |
267 | * If we are on the alternate signal stack and would overflow it, don't. | |
268 | * Return an always-bogus address instead so we will die with SIGSEGV. | |
269 | */ | |
270 | if (onsigstack && !likely(on_sig_stack(sp))) | |
271 | return (void __user *)-1L; | |
272 | ||
72a671ce | 273 | /* save i387 and extended state */ |
2722146e SAS |
274 | ret = copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size); |
275 | if (ret < 0) | |
14fc9fbc HS |
276 | return (void __user *)-1L; |
277 | ||
278 | return (void __user *)sp; | |
1da177e4 LT |
279 | } |
280 | ||
75779f05 HS |
281 | #ifdef CONFIG_X86_32 |
282 | static const struct { | |
283 | u16 poplmovl; | |
284 | u32 val; | |
285 | u16 int80; | |
286 | } __attribute__((packed)) retcode = { | |
287 | 0xb858, /* popl %eax; movl $..., %eax */ | |
288 | __NR_sigreturn, | |
289 | 0x80cd, /* int $0x80 */ | |
290 | }; | |
291 | ||
292 | static const struct { | |
293 | u8 movl; | |
294 | u32 val; | |
295 | u16 int80; | |
296 | u8 pad; | |
297 | } __attribute__((packed)) rt_retcode = { | |
298 | 0xb8, /* movl $..., %eax */ | |
299 | __NR_rt_sigreturn, | |
300 | 0x80cd, /* int $0x80 */ | |
301 | 0 | |
302 | }; | |
303 | ||
7e907f48 | 304 | static int |
235b8022 | 305 | __setup_frame(int sig, struct ksignal *ksig, sigset_t *set, |
1d13024e | 306 | struct pt_regs *regs) |
1da177e4 | 307 | { |
1da177e4 | 308 | struct sigframe __user *frame; |
7e907f48 | 309 | void __user *restorer; |
b00d8f8f | 310 | void __user *fp = NULL; |
1da177e4 | 311 | |
b00d8f8f | 312 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp); |
1da177e4 | 313 | |
5c1f1780 | 314 | if (!user_access_begin(frame, sizeof(*frame))) |
3d0aedd9 | 315 | return -EFAULT; |
1da177e4 | 316 | |
5c1f1780 | 317 | unsafe_put_user(sig, &frame->sig, Efault); |
b00d8f8f | 318 | unsafe_put_sigcontext(&frame->sc, fp, regs, set, Efault); |
5c1f1780 | 319 | unsafe_put_user(set->sig[1], &frame->extramask[0], Efault); |
1a3e4ca4 | 320 | if (current->mm->context.vdso) |
6f121e54 | 321 | restorer = current->mm->context.vdso + |
0a6d1fa0 | 322 | vdso_image_32.sym___kernel_sigreturn; |
9fbbd4dd | 323 | else |
ade1af77 | 324 | restorer = &frame->retcode; |
235b8022 AV |
325 | if (ksig->ka.sa.sa_flags & SA_RESTORER) |
326 | restorer = ksig->ka.sa.sa_restorer; | |
1da177e4 LT |
327 | |
328 | /* Set up to return from userspace. */ | |
5c1f1780 | 329 | unsafe_put_user(restorer, &frame->pretcode, Efault); |
7e907f48 | 330 | |
1da177e4 | 331 | /* |
7e907f48 | 332 | * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 |
1da177e4 LT |
333 | * |
334 | * WE DO NOT USE IT ANY MORE! It's only left here for historical | |
335 | * reasons and because gdb uses it as a signature to notice | |
336 | * signal handler stack frames. | |
337 | */ | |
5c1f1780 AV |
338 | unsafe_put_user(*((u64 *)&retcode), (u64 *)frame->retcode, Efault); |
339 | user_access_end(); | |
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; |
b00d8f8f AV |
354 | |
355 | Efault: | |
356 | user_access_end(); | |
357 | return -EFAULT; | |
1da177e4 LT |
358 | } |
359 | ||
235b8022 | 360 | static int __setup_rt_frame(int sig, struct ksignal *ksig, |
1d13024e | 361 | sigset_t *set, struct pt_regs *regs) |
1da177e4 | 362 | { |
1da177e4 | 363 | struct rt_sigframe __user *frame; |
7e907f48 | 364 | void __user *restorer; |
b00d8f8f | 365 | void __user *fp = NULL; |
1da177e4 | 366 | |
b00d8f8f | 367 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp); |
1da177e4 | 368 | |
119cd59f | 369 | if (!user_access_begin(frame, sizeof(*frame))) |
3d0aedd9 | 370 | return -EFAULT; |
1da177e4 | 371 | |
119cd59f AV |
372 | unsafe_put_user(sig, &frame->sig, Efault); |
373 | unsafe_put_user(&frame->info, &frame->pinfo, Efault); | |
374 | unsafe_put_user(&frame->uc, &frame->puc, Efault); | |
98e3d45e | 375 | |
119cd59f AV |
376 | /* Create the ucontext. */ |
377 | if (static_cpu_has(X86_FEATURE_XSAVE)) | |
378 | unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault); | |
379 | else | |
380 | unsafe_put_user(0, &frame->uc.uc_flags, Efault); | |
381 | unsafe_put_user(0, &frame->uc.uc_link, Efault); | |
382 | unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); | |
98e3d45e | 383 | |
119cd59f AV |
384 | /* Set up to return from userspace. */ |
385 | restorer = current->mm->context.vdso + | |
386 | vdso_image_32.sym___kernel_rt_sigreturn; | |
387 | if (ksig->ka.sa.sa_flags & SA_RESTORER) | |
388 | restorer = ksig->ka.sa.sa_restorer; | |
389 | unsafe_put_user(restorer, &frame->pretcode, Efault); | |
98e3d45e | 390 | |
119cd59f AV |
391 | /* |
392 | * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 | |
393 | * | |
394 | * WE DO NOT USE IT ANY MORE! It's only left here for historical | |
395 | * reasons and because gdb uses it as a signature to notice | |
396 | * signal handler stack frames. | |
397 | */ | |
398 | unsafe_put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode, Efault); | |
b00d8f8f | 399 | unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault); |
b87df659 | 400 | unsafe_put_sigmask(set, frame, Efault); |
119cd59f | 401 | user_access_end(); |
49b8c695 | 402 | |
ead8e4e7 | 403 | if (copy_siginfo_to_user(&frame->info, &ksig->info)) |
3d0aedd9 | 404 | return -EFAULT; |
1da177e4 LT |
405 | |
406 | /* Set up registers for signal handler */ | |
7e907f48 | 407 | regs->sp = (unsigned long)frame; |
235b8022 | 408 | regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
13ad7725 | 409 | regs->ax = (unsigned long)sig; |
7e907f48 IM |
410 | regs->dx = (unsigned long)&frame->info; |
411 | regs->cx = (unsigned long)&frame->uc; | |
1da177e4 | 412 | |
65ea5b03 PA |
413 | regs->ds = __USER_DS; |
414 | regs->es = __USER_DS; | |
415 | regs->ss = __USER_DS; | |
416 | regs->cs = __USER_CS; | |
1da177e4 | 417 | |
283828f3 | 418 | return 0; |
119cd59f AV |
419 | Efault: |
420 | user_access_end(); | |
421 | return -EFAULT; | |
1da177e4 | 422 | } |
bfeb91a9 | 423 | #else /* !CONFIG_X86_32 */ |
6c25da5a AL |
424 | static unsigned long frame_uc_flags(struct pt_regs *regs) |
425 | { | |
426 | unsigned long flags; | |
427 | ||
d366bf7e | 428 | if (boot_cpu_has(X86_FEATURE_XSAVE)) |
6c25da5a AL |
429 | flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS; |
430 | else | |
431 | flags = UC_SIGCONTEXT_SS; | |
432 | ||
433 | if (likely(user_64bit_mode(regs))) | |
434 | flags |= UC_STRICT_RESTORE_SS; | |
435 | ||
436 | return flags; | |
437 | } | |
438 | ||
235b8022 | 439 | static int __setup_rt_frame(int sig, struct ksignal *ksig, |
bfeb91a9 HS |
440 | sigset_t *set, struct pt_regs *regs) |
441 | { | |
442 | struct rt_sigframe __user *frame; | |
443 | void __user *fp = NULL; | |
88e47182 | 444 | unsigned long uc_flags; |
bfeb91a9 | 445 | |
119cd59f AV |
446 | /* x86-64 should always use SA_RESTORER. */ |
447 | if (!(ksig->ka.sa.sa_flags & SA_RESTORER)) | |
448 | return -EFAULT; | |
bfeb91a9 | 449 | |
235b8022 | 450 | frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp); |
88e47182 | 451 | uc_flags = frame_uc_flags(regs); |
bfeb91a9 | 452 | |
119cd59f | 453 | if (!user_access_begin(frame, sizeof(*frame))) |
bfeb91a9 HS |
454 | return -EFAULT; |
455 | ||
119cd59f AV |
456 | /* Create the ucontext. */ |
457 | unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault); | |
458 | unsafe_put_user(0, &frame->uc.uc_link, Efault); | |
459 | unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); | |
460 | ||
461 | /* Set up to return from userspace. If provided, use a stub | |
462 | already in userspace. */ | |
463 | unsafe_put_user(ksig->ka.sa.sa_restorer, &frame->pretcode, Efault); | |
b00d8f8f | 464 | unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault); |
b87df659 | 465 | unsafe_put_sigmask(set, frame, Efault); |
119cd59f | 466 | user_access_end(); |
5e88353d | 467 | |
235b8022 AV |
468 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
469 | if (copy_siginfo_to_user(&frame->info, &ksig->info)) | |
bfeb91a9 HS |
470 | return -EFAULT; |
471 | } | |
472 | ||
bfeb91a9 HS |
473 | /* Set up registers for signal handler */ |
474 | regs->di = sig; | |
475 | /* In case the signal handler was declared without prototypes */ | |
476 | regs->ax = 0; | |
477 | ||
478 | /* This also works for non SA_SIGINFO handlers because they expect the | |
479 | next argument after the signal number on the stack. */ | |
480 | regs->si = (unsigned long)&frame->info; | |
481 | regs->dx = (unsigned long)&frame->uc; | |
235b8022 | 482 | regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
bfeb91a9 HS |
483 | |
484 | regs->sp = (unsigned long)frame; | |
485 | ||
8ff5bd2e AL |
486 | /* |
487 | * Set up the CS and SS registers to run signal handlers in | |
488 | * 64-bit mode, even if the handler happens to be interrupting | |
489 | * 32-bit or 16-bit code. | |
490 | * | |
491 | * SS is subtle. In 64-bit mode, we don't need any particular | |
492 | * SS descriptor, but we do need SS to be valid. It's possible | |
493 | * that the old SS is entirely bogus -- this can happen if the | |
494 | * signal we're trying to deliver is #GP or #SS caused by a bad | |
495 | * SS value. We also have a compatbility issue here: DOSEMU | |
496 | * relies on the contents of the SS register indicating the | |
497 | * SS value at the time of the signal, even though that code in | |
498 | * DOSEMU predates sigreturn's ability to restore SS. (DOSEMU | |
499 | * avoids relying on sigreturn to restore SS; instead it uses | |
500 | * a trampoline.) So we do our best: if the old SS was valid, | |
501 | * we keep it. Otherwise we replace it. | |
502 | */ | |
bfeb91a9 HS |
503 | regs->cs = __USER_CS; |
504 | ||
8ff5bd2e AL |
505 | if (unlikely(regs->ss != __USER_DS)) |
506 | force_valid_ss(regs); | |
507 | ||
bfeb91a9 | 508 | return 0; |
119cd59f AV |
509 | |
510 | Efault: | |
511 | user_access_end(); | |
512 | return -EFAULT; | |
bfeb91a9 HS |
513 | } |
514 | #endif /* CONFIG_X86_32 */ | |
515 | ||
c3b3f524 CH |
516 | #ifdef CONFIG_X86_X32_ABI |
517 | static int x32_copy_siginfo_to_user(struct compat_siginfo __user *to, | |
518 | const struct kernel_siginfo *from) | |
519 | { | |
520 | struct compat_siginfo new; | |
521 | ||
522 | copy_siginfo_to_external32(&new, from); | |
523 | if (from->si_signo == SIGCHLD) { | |
524 | new._sifields._sigchld_x32._utime = from->si_utime; | |
525 | new._sifields._sigchld_x32._stime = from->si_stime; | |
526 | } | |
527 | if (copy_to_user(to, &new, sizeof(struct compat_siginfo))) | |
528 | return -EFAULT; | |
529 | return 0; | |
530 | } | |
531 | ||
532 | int copy_siginfo_to_user32(struct compat_siginfo __user *to, | |
533 | const struct kernel_siginfo *from) | |
534 | { | |
535 | if (in_x32_syscall()) | |
536 | return x32_copy_siginfo_to_user(to, from); | |
537 | return __copy_siginfo_to_user32(to, from); | |
538 | } | |
539 | #endif /* CONFIG_X86_X32_ABI */ | |
540 | ||
235b8022 AV |
541 | static int x32_setup_rt_frame(struct ksignal *ksig, |
542 | compat_sigset_t *set, | |
050902c0 SS |
543 | struct pt_regs *regs) |
544 | { | |
545 | #ifdef CONFIG_X86_X32_ABI | |
546 | struct rt_sigframe_x32 __user *frame; | |
88e47182 | 547 | unsigned long uc_flags; |
050902c0 | 548 | void __user *restorer; |
b00d8f8f | 549 | void __user *fp = NULL; |
050902c0 | 550 | |
39f16c1c | 551 | if (!(ksig->ka.sa.sa_flags & SA_RESTORER)) |
050902c0 SS |
552 | return -EFAULT; |
553 | ||
b00d8f8f | 554 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp); |
050902c0 | 555 | |
88e47182 PZ |
556 | uc_flags = frame_uc_flags(regs); |
557 | ||
39f16c1c AV |
558 | if (!user_access_begin(frame, sizeof(*frame))) |
559 | return -EFAULT; | |
050902c0 | 560 | |
39f16c1c AV |
561 | /* Create the ucontext. */ |
562 | unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault); | |
563 | unsafe_put_user(0, &frame->uc.uc_link, Efault); | |
564 | unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); | |
565 | unsafe_put_user(0, &frame->uc.uc__pad0, Efault); | |
566 | restorer = ksig->ka.sa.sa_restorer; | |
567 | unsafe_put_user(restorer, (unsigned long __user *)&frame->pretcode, Efault); | |
b00d8f8f | 568 | unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault); |
b87df659 | 569 | unsafe_put_sigmask(set, frame, Efault); |
39f16c1c | 570 | user_access_end(); |
49b8c695 | 571 | |
791612e9 | 572 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
c3b3f524 | 573 | if (x32_copy_siginfo_to_user(&frame->info, &ksig->info)) |
791612e9 AV |
574 | return -EFAULT; |
575 | } | |
050902c0 SS |
576 | |
577 | /* Set up registers for signal handler */ | |
578 | regs->sp = (unsigned long) frame; | |
235b8022 | 579 | regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
050902c0 SS |
580 | |
581 | /* We use the x32 calling convention here... */ | |
235b8022 | 582 | regs->di = ksig->sig; |
050902c0 SS |
583 | regs->si = (unsigned long) &frame->info; |
584 | regs->dx = (unsigned long) &frame->uc; | |
585 | ||
586 | loadsegment(ds, __USER_DS); | |
587 | loadsegment(es, __USER_DS); | |
588 | ||
589 | regs->cs = __USER_CS; | |
590 | regs->ss = __USER_DS; | |
591 | #endif /* CONFIG_X86_X32_ABI */ | |
592 | ||
593 | return 0; | |
39f16c1c AV |
594 | #ifdef CONFIG_X86_X32_ABI |
595 | Efault: | |
596 | user_access_end(); | |
597 | return -EFAULT; | |
598 | #endif | |
050902c0 SS |
599 | } |
600 | ||
bfeb91a9 HS |
601 | /* |
602 | * Do a signal return; undo the signal stack. | |
603 | */ | |
e5fa2d06 | 604 | #ifdef CONFIG_X86_32 |
4c8ca51a | 605 | SYSCALL_DEFINE0(sigreturn) |
bfeb91a9 | 606 | { |
3fe26fa3 | 607 | struct pt_regs *regs = current_pt_regs(); |
bfeb91a9 | 608 | struct sigframe __user *frame; |
bfeb91a9 HS |
609 | sigset_t set; |
610 | ||
bfeb91a9 HS |
611 | frame = (struct sigframe __user *)(regs->sp - 8); |
612 | ||
96d4f267 | 613 | if (!access_ok(frame, sizeof(*frame))) |
bfeb91a9 | 614 | goto badframe; |
71c3313a AV |
615 | if (__get_user(set.sig[0], &frame->sc.oldmask) || |
616 | __get_user(set.sig[1], &frame->extramask[0])) | |
bfeb91a9 HS |
617 | goto badframe; |
618 | ||
3982294b | 619 | set_current_blocked(&set); |
bfeb91a9 | 620 | |
6c25da5a AL |
621 | /* |
622 | * x86_32 has no uc_flags bits relevant to restore_sigcontext. | |
623 | * Save a few cycles by skipping the __get_user. | |
624 | */ | |
625 | if (restore_sigcontext(regs, &frame->sc, 0)) | |
bfeb91a9 | 626 | goto badframe; |
6a3713f0 | 627 | return regs->ax; |
bfeb91a9 HS |
628 | |
629 | badframe: | |
ae417bb4 | 630 | signal_fault(regs, frame, "sigreturn"); |
bfeb91a9 HS |
631 | |
632 | return 0; | |
633 | } | |
e5fa2d06 | 634 | #endif /* CONFIG_X86_32 */ |
bfeb91a9 | 635 | |
4c8ca51a | 636 | SYSCALL_DEFINE0(rt_sigreturn) |
bfeb91a9 | 637 | { |
3fe26fa3 | 638 | struct pt_regs *regs = current_pt_regs(); |
bfeb91a9 | 639 | struct rt_sigframe __user *frame; |
bfeb91a9 | 640 | sigset_t set; |
6c25da5a | 641 | unsigned long uc_flags; |
bfeb91a9 HS |
642 | |
643 | frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long)); | |
96d4f267 | 644 | if (!access_ok(frame, sizeof(*frame))) |
bfeb91a9 | 645 | goto badframe; |
71c3313a | 646 | if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask)) |
bfeb91a9 | 647 | goto badframe; |
6c25da5a AL |
648 | if (__get_user(uc_flags, &frame->uc.uc_flags)) |
649 | goto badframe; | |
bfeb91a9 | 650 | |
e9bd3f0f | 651 | set_current_blocked(&set); |
bfeb91a9 | 652 | |
6c25da5a | 653 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
bfeb91a9 HS |
654 | goto badframe; |
655 | ||
c40702c4 | 656 | if (restore_altstack(&frame->uc.uc_stack)) |
bfeb91a9 HS |
657 | goto badframe; |
658 | ||
6a3713f0 | 659 | return regs->ax; |
bfeb91a9 HS |
660 | |
661 | badframe: | |
662 | signal_fault(regs, frame, "rt_sigreturn"); | |
663 | return 0; | |
664 | } | |
665 | ||
68463510 | 666 | static inline int is_ia32_compat_frame(struct ksignal *ksig) |
05012c13 | 667 | { |
97f2645f | 668 | return IS_ENABLED(CONFIG_IA32_EMULATION) && |
68463510 | 669 | ksig->ka.sa.sa_flags & SA_IA32_ABI; |
05012c13 IM |
670 | } |
671 | ||
68463510 | 672 | static inline int is_ia32_frame(struct ksignal *ksig) |
05012c13 | 673 | { |
68463510 | 674 | return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig); |
05012c13 IM |
675 | } |
676 | ||
68463510 | 677 | static inline int is_x32_frame(struct ksignal *ksig) |
05012c13 | 678 | { |
68463510 DS |
679 | return IS_ENABLED(CONFIG_X86_X32_ABI) && |
680 | ksig->ka.sa.sa_flags & SA_X32_ABI; | |
05012c13 IM |
681 | } |
682 | ||
1d13024e | 683 | static int |
235b8022 | 684 | setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) |
1d13024e | 685 | { |
3050a35f | 686 | int usig = ksig->sig; |
b7f9a11a | 687 | sigset_t *set = sigmask_to_save(); |
050902c0 | 688 | compat_sigset_t *cset = (compat_sigset_t *) set; |
1d13024e | 689 | |
bff9504b | 690 | /* Perform fixup for the pre-signal frame. */ |
784e0300 | 691 | rseq_signal_deliver(ksig, regs); |
d6761b8f | 692 | |
1d13024e | 693 | /* Set up the stack frame */ |
68463510 | 694 | if (is_ia32_frame(ksig)) { |
235b8022 AV |
695 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
696 | return ia32_setup_rt_frame(usig, ksig, cset, regs); | |
455edbc4 | 697 | else |
235b8022 | 698 | return ia32_setup_frame(usig, ksig, cset, regs); |
68463510 | 699 | } else if (is_x32_frame(ksig)) { |
235b8022 | 700 | return x32_setup_rt_frame(ksig, cset, regs); |
c5a37394 | 701 | } else { |
235b8022 | 702 | return __setup_rt_frame(ksig->sig, ksig, set, regs); |
c5a37394 | 703 | } |
1d13024e HS |
704 | } |
705 | ||
a610d6e6 | 706 | static void |
235b8022 | 707 | handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
1da177e4 | 708 | { |
fd0f86b6 | 709 | bool stepping, failed; |
c5bedc68 | 710 | struct fpu *fpu = ¤t->thread.fpu; |
fd0f86b6 | 711 | |
5ed92a8a BG |
712 | if (v8086_mode(regs)) |
713 | save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL); | |
714 | ||
1da177e4 | 715 | /* Are we from a system call? */ |
bb57925f | 716 | if (syscall_get_nr(current, regs) >= 0) { |
1da177e4 | 717 | /* If so, check system call restarting.. */ |
bb57925f | 718 | switch (syscall_get_error(current, regs)) { |
ac66f3fd HH |
719 | case -ERESTART_RESTARTBLOCK: |
720 | case -ERESTARTNOHAND: | |
721 | regs->ax = -EINTR; | |
722 | break; | |
723 | ||
724 | case -ERESTARTSYS: | |
235b8022 | 725 | if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { |
65ea5b03 | 726 | regs->ax = -EINTR; |
1da177e4 | 727 | break; |
ac66f3fd | 728 | } |
df561f66 | 729 | fallthrough; |
ac66f3fd HH |
730 | case -ERESTARTNOINTR: |
731 | regs->ax = regs->orig_ax; | |
732 | regs->ip -= 2; | |
733 | break; | |
1da177e4 LT |
734 | } |
735 | } | |
736 | ||
737 | /* | |
fd0f86b6 ON |
738 | * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now |
739 | * so that register information in the sigcontext is correct and | |
740 | * then notify the tracer before entering the signal handler. | |
1da177e4 | 741 | */ |
fd0f86b6 ON |
742 | stepping = test_thread_flag(TIF_SINGLESTEP); |
743 | if (stepping) | |
744 | user_disable_single_step(current); | |
1da177e4 | 745 | |
235b8022 AV |
746 | failed = (setup_rt_frame(ksig, regs) < 0); |
747 | if (!failed) { | |
748 | /* | |
749 | * Clear the direction flag as per the ABI for function entry. | |
ddd40da4 | 750 | * |
24cda109 JO |
751 | * Clear RF when entering the signal handler, because |
752 | * it might disable possible debug exception from the | |
753 | * signal handler. | |
ddd40da4 | 754 | * |
fd0f86b6 ON |
755 | * Clear TF for the case when it wasn't set by debugger to |
756 | * avoid the recursive send_sigtrap() in SIGTRAP handler. | |
235b8022 | 757 | */ |
ddd40da4 | 758 | regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); |
66463db4 ON |
759 | /* |
760 | * Ensure the signal handler starts with the new fpu state. | |
761 | */ | |
b860eb8d | 762 | fpu__clear_user_states(fpu); |
a610d6e6 | 763 | } |
fd0f86b6 | 764 | signal_setup_done(failed, ksig, stepping); |
1da177e4 LT |
765 | } |
766 | ||
22eab110 DL |
767 | static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs) |
768 | { | |
609c19a3 AL |
769 | /* |
770 | * This function is fundamentally broken as currently | |
771 | * implemented. | |
772 | * | |
773 | * The idea is that we want to trigger a call to the | |
774 | * restart_block() syscall and that we want in_ia32_syscall(), | |
775 | * in_x32_syscall(), etc. to match whatever they were in the | |
776 | * syscall being restarted. We assume that the syscall | |
777 | * instruction at (regs->ip - 2) matches whatever syscall | |
778 | * instruction we used to enter in the first place. | |
779 | * | |
780 | * The problem is that we can get here when ptrace pokes | |
781 | * syscall-like values into regs even if we're not in a syscall | |
782 | * at all. | |
783 | * | |
784 | * For now, we maintain historical behavior and guess based on | |
785 | * stored state. We could do better by saving the actual | |
786 | * syscall arch in restart_block or (with caveats on x32) by | |
787 | * checking if regs->ip points to 'int $0x80'. The current | |
788 | * behavior is incorrect if a tracer has a different bitness | |
789 | * than the tracee. | |
790 | */ | |
791 | #ifdef CONFIG_IA32_EMULATION | |
37a8f7c3 | 792 | if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED)) |
95d97adb DL |
793 | return __NR_ia32_restart_syscall; |
794 | #endif | |
795 | #ifdef CONFIG_X86_X32_ABI | |
796 | return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT); | |
797 | #else | |
22eab110 | 798 | return __NR_restart_syscall; |
95d97adb | 799 | #endif |
22eab110 | 800 | } |
57917752 | 801 | |
1da177e4 LT |
802 | /* |
803 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
804 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
805 | * mistake. | |
806 | */ | |
167fd210 | 807 | void arch_do_signal(struct pt_regs *regs) |
1da177e4 | 808 | { |
235b8022 | 809 | struct ksignal ksig; |
1da177e4 | 810 | |
235b8022 | 811 | if (get_signal(&ksig)) { |
7e907f48 | 812 | /* Whee! Actually deliver the signal. */ |
235b8022 | 813 | handle_signal(&ksig, regs); |
283828f3 | 814 | return; |
1da177e4 LT |
815 | } |
816 | ||
1da177e4 | 817 | /* Did we come from a system call? */ |
bb57925f | 818 | if (syscall_get_nr(current, regs) >= 0) { |
1da177e4 | 819 | /* Restart the system call - no handlers present */ |
bb57925f | 820 | switch (syscall_get_error(current, regs)) { |
283828f3 DH |
821 | case -ERESTARTNOHAND: |
822 | case -ERESTARTSYS: | |
823 | case -ERESTARTNOINTR: | |
65ea5b03 PA |
824 | regs->ax = regs->orig_ax; |
825 | regs->ip -= 2; | |
283828f3 DH |
826 | break; |
827 | ||
828 | case -ERESTART_RESTARTBLOCK: | |
22eab110 | 829 | regs->ax = get_nr_restart_syscall(regs); |
65ea5b03 | 830 | regs->ip -= 2; |
283828f3 | 831 | break; |
1da177e4 LT |
832 | } |
833 | } | |
283828f3 | 834 | |
ac66f3fd HH |
835 | /* |
836 | * If there's no signal to deliver, we just put the saved sigmask | |
837 | * back. | |
838 | */ | |
51a7b448 | 839 | restore_saved_sigmask(); |
1da177e4 LT |
840 | } |
841 | ||
72fa50f4 HS |
842 | void signal_fault(struct pt_regs *regs, void __user *frame, char *where) |
843 | { | |
844 | struct task_struct *me = current; | |
845 | ||
846 | if (show_unhandled_signals && printk_ratelimit()) { | |
ae417bb4 | 847 | printk("%s" |
72fa50f4 | 848 | "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", |
ae417bb4 | 849 | task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, |
72fa50f4 HS |
850 | me->comm, me->pid, where, frame, |
851 | regs->ip, regs->sp, regs->orig_ax); | |
1c99a687 | 852 | print_vma_addr(KERN_CONT " in ", regs->ip); |
c767a54b | 853 | pr_cont("\n"); |
72fa50f4 HS |
854 | } |
855 | ||
3cf5d076 | 856 | force_sig(SIGSEGV); |
72fa50f4 | 857 | } |
c5a37394 PA |
858 | |
859 | #ifdef CONFIG_X86_X32_ABI | |
27dd84fa | 860 | COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn) |
c5a37394 | 861 | { |
3fe26fa3 | 862 | struct pt_regs *regs = current_pt_regs(); |
c5a37394 PA |
863 | struct rt_sigframe_x32 __user *frame; |
864 | sigset_t set; | |
6c25da5a | 865 | unsigned long uc_flags; |
c5a37394 PA |
866 | |
867 | frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); | |
868 | ||
96d4f267 | 869 | if (!access_ok(frame, sizeof(*frame))) |
c5a37394 | 870 | goto badframe; |
71c3313a | 871 | if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask)) |
c5a37394 | 872 | goto badframe; |
6c25da5a AL |
873 | if (__get_user(uc_flags, &frame->uc.uc_flags)) |
874 | goto badframe; | |
c5a37394 | 875 | |
c5a37394 PA |
876 | set_current_blocked(&set); |
877 | ||
6c25da5a | 878 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
c5a37394 PA |
879 | goto badframe; |
880 | ||
90268439 | 881 | if (compat_restore_altstack(&frame->uc.uc_stack)) |
c5a37394 PA |
882 | goto badframe; |
883 | ||
6a3713f0 | 884 | return regs->ax; |
c5a37394 PA |
885 | |
886 | badframe: | |
887 | signal_fault(regs, frame, "x32 rt_sigreturn"); | |
888 | return 0; | |
889 | } | |
890 | #endif |