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> |
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 | |
d9a89a26 TH |
50 | #define COPY(x) do { \ |
51 | get_user_ex(regs->x, &sc->x); \ | |
52 | } while (0) | |
2601657d | 53 | |
d9a89a26 TH |
54 | #define GET_SEG(seg) ({ \ |
55 | unsigned short tmp; \ | |
56 | get_user_ex(tmp, &sc->seg); \ | |
57 | tmp; \ | |
58 | }) | |
2601657d | 59 | |
d9a89a26 TH |
60 | #define COPY_SEG(seg) do { \ |
61 | regs->seg = GET_SEG(seg); \ | |
62 | } while (0) | |
2601657d | 63 | |
d9a89a26 TH |
64 | #define COPY_SEG_CPL3(seg) do { \ |
65 | regs->seg = GET_SEG(seg) | 3; \ | |
66 | } while (0) | |
2601657d | 67 | |
8ff5bd2e AL |
68 | #ifdef CONFIG_X86_64 |
69 | /* | |
70 | * If regs->ss will cause an IRET fault, change it. Otherwise leave it | |
71 | * alone. Using this generally makes no sense unless | |
72 | * user_64bit_mode(regs) would return true. | |
73 | */ | |
74 | static void force_valid_ss(struct pt_regs *regs) | |
75 | { | |
76 | u32 ar; | |
77 | asm volatile ("lar %[old_ss], %[ar]\n\t" | |
78 | "jz 1f\n\t" /* If invalid: */ | |
79 | "xorl %[ar], %[ar]\n\t" /* set ar = 0 */ | |
80 | "1:" | |
81 | : [ar] "=r" (ar) | |
82 | : [old_ss] "rm" ((u16)regs->ss)); | |
83 | ||
84 | /* | |
85 | * For a valid 64-bit user context, we need DPL 3, type | |
86 | * read-write data or read-write exp-down data, and S and P | |
87 | * set. We can't use VERW because VERW doesn't check the | |
88 | * P bit. | |
89 | */ | |
90 | ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK; | |
91 | if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) && | |
92 | ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN)) | |
93 | regs->ss = __USER_DS; | |
94 | } | |
95 | #endif | |
96 | ||
6c25da5a AL |
97 | static int restore_sigcontext(struct pt_regs *regs, |
98 | struct sigcontext __user *sc, | |
99 | unsigned long uc_flags) | |
2601657d | 100 | { |
530e5c82 | 101 | unsigned long buf_val; |
2601657d HS |
102 | void __user *buf; |
103 | unsigned int tmpflags; | |
104 | unsigned int err = 0; | |
105 | ||
106 | /* Always make any pending restarted system calls return -EINTR */ | |
f56141e3 | 107 | current->restart_block.fn = do_no_restart_syscall; |
2601657d | 108 | |
98e3d45e HS |
109 | get_user_try { |
110 | ||
2601657d | 111 | #ifdef CONFIG_X86_32 |
d9a89a26 | 112 | set_user_gs(regs, GET_SEG(gs)); |
98e3d45e HS |
113 | COPY_SEG(fs); |
114 | COPY_SEG(es); | |
115 | COPY_SEG(ds); | |
2601657d HS |
116 | #endif /* CONFIG_X86_32 */ |
117 | ||
98e3d45e | 118 | COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx); |
6a3713f0 | 119 | COPY(dx); COPY(cx); COPY(ip); COPY(ax); |
2601657d HS |
120 | |
121 | #ifdef CONFIG_X86_64 | |
98e3d45e HS |
122 | COPY(r8); |
123 | COPY(r9); | |
124 | COPY(r10); | |
125 | COPY(r11); | |
126 | COPY(r12); | |
127 | COPY(r13); | |
128 | COPY(r14); | |
129 | COPY(r15); | |
2601657d HS |
130 | #endif /* CONFIG_X86_64 */ |
131 | ||
98e3d45e HS |
132 | COPY_SEG_CPL3(cs); |
133 | COPY_SEG_CPL3(ss); | |
6c25da5a AL |
134 | |
135 | #ifdef CONFIG_X86_64 | |
136 | /* | |
137 | * Fix up SS if needed for the benefit of old DOSEMU and | |
138 | * CRIU. | |
139 | */ | |
140 | if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && | |
141 | user_64bit_mode(regs))) | |
142 | force_valid_ss(regs); | |
143 | #endif | |
2601657d | 144 | |
98e3d45e HS |
145 | get_user_ex(tmpflags, &sc->flags); |
146 | regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS); | |
147 | regs->orig_ax = -1; /* disable syscall checks */ | |
148 | ||
530e5c82 IM |
149 | get_user_ex(buf_val, &sc->fpstate); |
150 | buf = (void __user *)buf_val; | |
98e3d45e | 151 | } get_user_catch(err); |
2601657d | 152 | |
97f2645f | 153 | err |= fpu__restore_sig(buf, IS_ENABLED(CONFIG_X86_32)); |
5e88353d | 154 | |
1daeaa31 BG |
155 | force_iret(); |
156 | ||
2601657d HS |
157 | return err; |
158 | } | |
159 | ||
85139422 PA |
160 | int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, |
161 | struct pt_regs *regs, unsigned long mask) | |
2601657d HS |
162 | { |
163 | int err = 0; | |
164 | ||
98e3d45e | 165 | put_user_try { |
2601657d | 166 | |
98e3d45e | 167 | #ifdef CONFIG_X86_32 |
d9a89a26 | 168 | put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs); |
98e3d45e HS |
169 | put_user_ex(regs->fs, (unsigned int __user *)&sc->fs); |
170 | put_user_ex(regs->es, (unsigned int __user *)&sc->es); | |
171 | put_user_ex(regs->ds, (unsigned int __user *)&sc->ds); | |
2601657d HS |
172 | #endif /* CONFIG_X86_32 */ |
173 | ||
98e3d45e HS |
174 | put_user_ex(regs->di, &sc->di); |
175 | put_user_ex(regs->si, &sc->si); | |
176 | put_user_ex(regs->bp, &sc->bp); | |
177 | put_user_ex(regs->sp, &sc->sp); | |
178 | put_user_ex(regs->bx, &sc->bx); | |
179 | put_user_ex(regs->dx, &sc->dx); | |
180 | put_user_ex(regs->cx, &sc->cx); | |
181 | put_user_ex(regs->ax, &sc->ax); | |
2601657d | 182 | #ifdef CONFIG_X86_64 |
98e3d45e HS |
183 | put_user_ex(regs->r8, &sc->r8); |
184 | put_user_ex(regs->r9, &sc->r9); | |
185 | put_user_ex(regs->r10, &sc->r10); | |
186 | put_user_ex(regs->r11, &sc->r11); | |
187 | put_user_ex(regs->r12, &sc->r12); | |
188 | put_user_ex(regs->r13, &sc->r13); | |
189 | put_user_ex(regs->r14, &sc->r14); | |
190 | put_user_ex(regs->r15, &sc->r15); | |
2601657d HS |
191 | #endif /* CONFIG_X86_64 */ |
192 | ||
51e7dc70 | 193 | put_user_ex(current->thread.trap_nr, &sc->trapno); |
98e3d45e HS |
194 | put_user_ex(current->thread.error_code, &sc->err); |
195 | put_user_ex(regs->ip, &sc->ip); | |
2601657d | 196 | #ifdef CONFIG_X86_32 |
98e3d45e HS |
197 | put_user_ex(regs->cs, (unsigned int __user *)&sc->cs); |
198 | put_user_ex(regs->flags, &sc->flags); | |
199 | put_user_ex(regs->sp, &sc->sp_at_signal); | |
200 | put_user_ex(regs->ss, (unsigned int __user *)&sc->ss); | |
2601657d | 201 | #else /* !CONFIG_X86_32 */ |
98e3d45e HS |
202 | put_user_ex(regs->flags, &sc->flags); |
203 | put_user_ex(regs->cs, &sc->cs); | |
ed596cde LT |
204 | put_user_ex(0, &sc->gs); |
205 | put_user_ex(0, &sc->fs); | |
6c25da5a | 206 | put_user_ex(regs->ss, &sc->ss); |
2601657d HS |
207 | #endif /* CONFIG_X86_32 */ |
208 | ||
98e3d45e | 209 | put_user_ex(fpstate, &sc->fpstate); |
2601657d | 210 | |
98e3d45e HS |
211 | /* non-iBCS2 extensions.. */ |
212 | put_user_ex(mask, &sc->oldmask); | |
213 | put_user_ex(current->thread.cr2, &sc->cr2); | |
214 | } put_user_catch(err); | |
2601657d HS |
215 | |
216 | return err; | |
217 | } | |
218 | ||
1da177e4 | 219 | /* |
bfeb91a9 | 220 | * Set up a signal frame. |
1da177e4 | 221 | */ |
1da177e4 LT |
222 | |
223 | /* | |
224 | * Determine which stack to use.. | |
225 | */ | |
1fae0279 HS |
226 | static unsigned long align_sigframe(unsigned long sp) |
227 | { | |
228 | #ifdef CONFIG_X86_32 | |
229 | /* | |
230 | * Align the stack pointer according to the i386 ABI, | |
231 | * i.e. so that on function entry ((sp + 4) & 15) == 0. | |
232 | */ | |
233 | sp = ((sp + 4) & -16ul) - 4; | |
234 | #else /* !CONFIG_X86_32 */ | |
235 | sp = round_down(sp, 16) - 8; | |
236 | #endif | |
237 | return sp; | |
238 | } | |
239 | ||
dae0f305 | 240 | static void __user * |
3c1c7f10 | 241 | get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, |
144b0712 | 242 | void __user **fpstate) |
1da177e4 | 243 | { |
1da177e4 | 244 | /* Default to using normal stack */ |
72a671ce | 245 | unsigned long math_size = 0; |
75779f05 | 246 | unsigned long sp = regs->sp; |
72a671ce | 247 | unsigned long buf_fx = 0; |
14fc9fbc | 248 | int onsigstack = on_sig_stack(sp); |
c5bedc68 | 249 | struct fpu *fpu = ¤t->thread.fpu; |
75779f05 | 250 | |
75779f05 | 251 | /* redzone */ |
97f2645f | 252 | if (IS_ENABLED(CONFIG_X86_64)) |
050902c0 | 253 | sp -= 128; |
1da177e4 | 254 | |
0b4521e8 SS |
255 | /* This is the X/Open sanctioned signal stack switching. */ |
256 | if (ka->sa.sa_flags & SA_ONSTACK) { | |
257 | if (sas_ss_flags(sp) == 0) | |
258 | sp = current->sas_ss_sp + current->sas_ss_size; | |
97f2645f | 259 | } else if (IS_ENABLED(CONFIG_X86_32) && |
0b4521e8 | 260 | !onsigstack && |
99504819 | 261 | regs->ss != __USER_DS && |
0b4521e8 SS |
262 | !(ka->sa.sa_flags & SA_RESTORER) && |
263 | ka->sa.sa_restorer) { | |
264 | /* This is the legacy signal stack switching. */ | |
265 | sp = (unsigned long) ka->sa.sa_restorer; | |
1da177e4 LT |
266 | } |
267 | ||
e4a81bfc | 268 | if (fpu->initialized) { |
97f2645f | 269 | sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32), |
82c0e45e | 270 | &buf_fx, &math_size); |
25051702 | 271 | *fpstate = (void __user *)sp; |
3c1c7f10 SS |
272 | } |
273 | ||
14fc9fbc HS |
274 | sp = align_sigframe(sp - frame_size); |
275 | ||
276 | /* | |
277 | * If we are on the alternate signal stack and would overflow it, don't. | |
278 | * Return an always-bogus address instead so we will die with SIGSEGV. | |
279 | */ | |
280 | if (onsigstack && !likely(on_sig_stack(sp))) | |
281 | return (void __user *)-1L; | |
282 | ||
72a671ce | 283 | /* save i387 and extended state */ |
e4a81bfc | 284 | if (fpu->initialized && |
c8e14041 | 285 | copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0) |
14fc9fbc HS |
286 | return (void __user *)-1L; |
287 | ||
288 | return (void __user *)sp; | |
1da177e4 LT |
289 | } |
290 | ||
75779f05 HS |
291 | #ifdef CONFIG_X86_32 |
292 | static const struct { | |
293 | u16 poplmovl; | |
294 | u32 val; | |
295 | u16 int80; | |
296 | } __attribute__((packed)) retcode = { | |
297 | 0xb858, /* popl %eax; movl $..., %eax */ | |
298 | __NR_sigreturn, | |
299 | 0x80cd, /* int $0x80 */ | |
300 | }; | |
301 | ||
302 | static const struct { | |
303 | u8 movl; | |
304 | u32 val; | |
305 | u16 int80; | |
306 | u8 pad; | |
307 | } __attribute__((packed)) rt_retcode = { | |
308 | 0xb8, /* movl $..., %eax */ | |
309 | __NR_rt_sigreturn, | |
310 | 0x80cd, /* int $0x80 */ | |
311 | 0 | |
312 | }; | |
313 | ||
7e907f48 | 314 | static int |
235b8022 | 315 | __setup_frame(int sig, struct ksignal *ksig, sigset_t *set, |
1d13024e | 316 | struct pt_regs *regs) |
1da177e4 | 317 | { |
1da177e4 | 318 | struct sigframe __user *frame; |
7e907f48 | 319 | void __user *restorer; |
1da177e4 | 320 | int err = 0; |
ab513701 | 321 | void __user *fpstate = NULL; |
1da177e4 | 322 | |
235b8022 | 323 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); |
1da177e4 LT |
324 | |
325 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
3d0aedd9 | 326 | return -EFAULT; |
1da177e4 | 327 | |
2ba48e16 | 328 | if (__put_user(sig, &frame->sig)) |
3d0aedd9 | 329 | return -EFAULT; |
1da177e4 | 330 | |
2ba48e16 | 331 | if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0])) |
3d0aedd9 | 332 | return -EFAULT; |
1da177e4 LT |
333 | |
334 | if (_NSIG_WORDS > 1) { | |
2ba48e16 HS |
335 | if (__copy_to_user(&frame->extramask, &set->sig[1], |
336 | sizeof(frame->extramask))) | |
3d0aedd9 | 337 | return -EFAULT; |
1da177e4 LT |
338 | } |
339 | ||
1a3e4ca4 | 340 | if (current->mm->context.vdso) |
6f121e54 | 341 | restorer = current->mm->context.vdso + |
0a6d1fa0 | 342 | vdso_image_32.sym___kernel_sigreturn; |
9fbbd4dd | 343 | else |
ade1af77 | 344 | restorer = &frame->retcode; |
235b8022 AV |
345 | if (ksig->ka.sa.sa_flags & SA_RESTORER) |
346 | restorer = ksig->ka.sa.sa_restorer; | |
1da177e4 LT |
347 | |
348 | /* Set up to return from userspace. */ | |
349 | err |= __put_user(restorer, &frame->pretcode); | |
7e907f48 | 350 | |
1da177e4 | 351 | /* |
7e907f48 | 352 | * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 |
1da177e4 LT |
353 | * |
354 | * WE DO NOT USE IT ANY MORE! It's only left here for historical | |
355 | * reasons and because gdb uses it as a signature to notice | |
356 | * signal handler stack frames. | |
357 | */ | |
4a612048 | 358 | err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode); |
1da177e4 LT |
359 | |
360 | if (err) | |
3d0aedd9 | 361 | return -EFAULT; |
1da177e4 LT |
362 | |
363 | /* Set up registers for signal handler */ | |
7e907f48 | 364 | regs->sp = (unsigned long)frame; |
235b8022 | 365 | regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
7e907f48 | 366 | regs->ax = (unsigned long)sig; |
92bc2056 HH |
367 | regs->dx = 0; |
368 | regs->cx = 0; | |
1da177e4 | 369 | |
65ea5b03 PA |
370 | regs->ds = __USER_DS; |
371 | regs->es = __USER_DS; | |
372 | regs->ss = __USER_DS; | |
373 | regs->cs = __USER_CS; | |
1da177e4 | 374 | |
283828f3 | 375 | return 0; |
1da177e4 LT |
376 | } |
377 | ||
235b8022 | 378 | static int __setup_rt_frame(int sig, struct ksignal *ksig, |
1d13024e | 379 | sigset_t *set, struct pt_regs *regs) |
1da177e4 | 380 | { |
1da177e4 | 381 | struct rt_sigframe __user *frame; |
7e907f48 | 382 | void __user *restorer; |
1da177e4 | 383 | int err = 0; |
ab513701 | 384 | void __user *fpstate = NULL; |
1da177e4 | 385 | |
235b8022 | 386 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); |
1da177e4 LT |
387 | |
388 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
3d0aedd9 | 389 | return -EFAULT; |
1da177e4 | 390 | |
98e3d45e HS |
391 | put_user_try { |
392 | put_user_ex(sig, &frame->sig); | |
393 | put_user_ex(&frame->info, &frame->pinfo); | |
394 | put_user_ex(&frame->uc, &frame->puc); | |
98e3d45e HS |
395 | |
396 | /* Create the ucontext. */ | |
d366bf7e | 397 | if (boot_cpu_has(X86_FEATURE_XSAVE)) |
98e3d45e HS |
398 | put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); |
399 | else | |
400 | put_user_ex(0, &frame->uc.uc_flags); | |
401 | put_user_ex(0, &frame->uc.uc_link); | |
bd1c149a | 402 | save_altstack_ex(&frame->uc.uc_stack, regs->sp); |
98e3d45e HS |
403 | |
404 | /* Set up to return from userspace. */ | |
6f121e54 | 405 | restorer = current->mm->context.vdso + |
0a6d1fa0 | 406 | vdso_image_32.sym___kernel_rt_sigreturn; |
235b8022 AV |
407 | if (ksig->ka.sa.sa_flags & SA_RESTORER) |
408 | restorer = ksig->ka.sa.sa_restorer; | |
98e3d45e HS |
409 | put_user_ex(restorer, &frame->pretcode); |
410 | ||
411 | /* | |
412 | * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 | |
413 | * | |
414 | * WE DO NOT USE IT ANY MORE! It's only left here for historical | |
415 | * reasons and because gdb uses it as a signature to notice | |
416 | * signal handler stack frames. | |
417 | */ | |
418 | put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode); | |
419 | } put_user_catch(err); | |
49b8c695 | 420 | |
235b8022 | 421 | err |= copy_siginfo_to_user(&frame->info, &ksig->info); |
5e88353d PA |
422 | err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, |
423 | regs, set->sig[0]); | |
424 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
1da177e4 LT |
425 | |
426 | if (err) | |
3d0aedd9 | 427 | return -EFAULT; |
1da177e4 LT |
428 | |
429 | /* Set up registers for signal handler */ | |
7e907f48 | 430 | regs->sp = (unsigned long)frame; |
235b8022 | 431 | regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
13ad7725 | 432 | regs->ax = (unsigned long)sig; |
7e907f48 IM |
433 | regs->dx = (unsigned long)&frame->info; |
434 | regs->cx = (unsigned long)&frame->uc; | |
1da177e4 | 435 | |
65ea5b03 PA |
436 | regs->ds = __USER_DS; |
437 | regs->es = __USER_DS; | |
438 | regs->ss = __USER_DS; | |
439 | regs->cs = __USER_CS; | |
1da177e4 | 440 | |
283828f3 | 441 | return 0; |
1da177e4 | 442 | } |
bfeb91a9 | 443 | #else /* !CONFIG_X86_32 */ |
6c25da5a AL |
444 | static unsigned long frame_uc_flags(struct pt_regs *regs) |
445 | { | |
446 | unsigned long flags; | |
447 | ||
d366bf7e | 448 | if (boot_cpu_has(X86_FEATURE_XSAVE)) |
6c25da5a AL |
449 | flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS; |
450 | else | |
451 | flags = UC_SIGCONTEXT_SS; | |
452 | ||
453 | if (likely(user_64bit_mode(regs))) | |
454 | flags |= UC_STRICT_RESTORE_SS; | |
455 | ||
456 | return flags; | |
457 | } | |
458 | ||
235b8022 | 459 | static int __setup_rt_frame(int sig, struct ksignal *ksig, |
bfeb91a9 HS |
460 | sigset_t *set, struct pt_regs *regs) |
461 | { | |
462 | struct rt_sigframe __user *frame; | |
463 | void __user *fp = NULL; | |
464 | int err = 0; | |
bfeb91a9 | 465 | |
235b8022 | 466 | frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp); |
bfeb91a9 HS |
467 | |
468 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
469 | return -EFAULT; | |
470 | ||
235b8022 AV |
471 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
472 | if (copy_siginfo_to_user(&frame->info, &ksig->info)) | |
bfeb91a9 HS |
473 | return -EFAULT; |
474 | } | |
475 | ||
98e3d45e HS |
476 | put_user_try { |
477 | /* Create the ucontext. */ | |
6c25da5a | 478 | put_user_ex(frame_uc_flags(regs), &frame->uc.uc_flags); |
98e3d45e | 479 | put_user_ex(0, &frame->uc.uc_link); |
bd1c149a | 480 | save_altstack_ex(&frame->uc.uc_stack, regs->sp); |
98e3d45e HS |
481 | |
482 | /* Set up to return from userspace. If provided, use a stub | |
483 | already in userspace. */ | |
484 | /* x86-64 should always use SA_RESTORER. */ | |
235b8022 AV |
485 | if (ksig->ka.sa.sa_flags & SA_RESTORER) { |
486 | put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode); | |
98e3d45e HS |
487 | } else { |
488 | /* could use a vstub here */ | |
489 | err |= -EFAULT; | |
490 | } | |
491 | } put_user_catch(err); | |
bfeb91a9 | 492 | |
5e88353d PA |
493 | err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]); |
494 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
495 | ||
bfeb91a9 HS |
496 | if (err) |
497 | return -EFAULT; | |
498 | ||
499 | /* Set up registers for signal handler */ | |
500 | regs->di = sig; | |
501 | /* In case the signal handler was declared without prototypes */ | |
502 | regs->ax = 0; | |
503 | ||
504 | /* This also works for non SA_SIGINFO handlers because they expect the | |
505 | next argument after the signal number on the stack. */ | |
506 | regs->si = (unsigned long)&frame->info; | |
507 | regs->dx = (unsigned long)&frame->uc; | |
235b8022 | 508 | regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
bfeb91a9 HS |
509 | |
510 | regs->sp = (unsigned long)frame; | |
511 | ||
8ff5bd2e AL |
512 | /* |
513 | * Set up the CS and SS registers to run signal handlers in | |
514 | * 64-bit mode, even if the handler happens to be interrupting | |
515 | * 32-bit or 16-bit code. | |
516 | * | |
517 | * SS is subtle. In 64-bit mode, we don't need any particular | |
518 | * SS descriptor, but we do need SS to be valid. It's possible | |
519 | * that the old SS is entirely bogus -- this can happen if the | |
520 | * signal we're trying to deliver is #GP or #SS caused by a bad | |
521 | * SS value. We also have a compatbility issue here: DOSEMU | |
522 | * relies on the contents of the SS register indicating the | |
523 | * SS value at the time of the signal, even though that code in | |
524 | * DOSEMU predates sigreturn's ability to restore SS. (DOSEMU | |
525 | * avoids relying on sigreturn to restore SS; instead it uses | |
526 | * a trampoline.) So we do our best: if the old SS was valid, | |
527 | * we keep it. Otherwise we replace it. | |
528 | */ | |
bfeb91a9 HS |
529 | regs->cs = __USER_CS; |
530 | ||
8ff5bd2e AL |
531 | if (unlikely(regs->ss != __USER_DS)) |
532 | force_valid_ss(regs); | |
533 | ||
bfeb91a9 HS |
534 | return 0; |
535 | } | |
536 | #endif /* CONFIG_X86_32 */ | |
537 | ||
235b8022 AV |
538 | static int x32_setup_rt_frame(struct ksignal *ksig, |
539 | compat_sigset_t *set, | |
050902c0 SS |
540 | struct pt_regs *regs) |
541 | { | |
542 | #ifdef CONFIG_X86_X32_ABI | |
543 | struct rt_sigframe_x32 __user *frame; | |
544 | void __user *restorer; | |
545 | int err = 0; | |
546 | void __user *fpstate = NULL; | |
547 | ||
235b8022 | 548 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); |
050902c0 SS |
549 | |
550 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
551 | return -EFAULT; | |
552 | ||
235b8022 | 553 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
68463510 | 554 | if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true)) |
050902c0 SS |
555 | return -EFAULT; |
556 | } | |
557 | ||
558 | put_user_try { | |
559 | /* Create the ucontext. */ | |
6c25da5a | 560 | put_user_ex(frame_uc_flags(regs), &frame->uc.uc_flags); |
050902c0 | 561 | put_user_ex(0, &frame->uc.uc_link); |
bd1c149a | 562 | compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp); |
050902c0 | 563 | put_user_ex(0, &frame->uc.uc__pad0); |
050902c0 | 564 | |
235b8022 AV |
565 | if (ksig->ka.sa.sa_flags & SA_RESTORER) { |
566 | restorer = ksig->ka.sa.sa_restorer; | |
050902c0 SS |
567 | } else { |
568 | /* could use a vstub here */ | |
569 | restorer = NULL; | |
570 | err |= -EFAULT; | |
571 | } | |
572 | put_user_ex(restorer, &frame->pretcode); | |
573 | } put_user_catch(err); | |
574 | ||
49b8c695 PA |
575 | err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, |
576 | regs, set->sig[0]); | |
577 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
578 | ||
050902c0 SS |
579 | if (err) |
580 | return -EFAULT; | |
581 | ||
582 | /* Set up registers for signal handler */ | |
583 | regs->sp = (unsigned long) frame; | |
235b8022 | 584 | regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
050902c0 SS |
585 | |
586 | /* We use the x32 calling convention here... */ | |
235b8022 | 587 | regs->di = ksig->sig; |
050902c0 SS |
588 | regs->si = (unsigned long) &frame->info; |
589 | regs->dx = (unsigned long) &frame->uc; | |
590 | ||
591 | loadsegment(ds, __USER_DS); | |
592 | loadsegment(es, __USER_DS); | |
593 | ||
594 | regs->cs = __USER_CS; | |
595 | regs->ss = __USER_DS; | |
596 | #endif /* CONFIG_X86_X32_ABI */ | |
597 | ||
598 | return 0; | |
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 | ||
613 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
614 | goto badframe; | |
615 | if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1 | |
616 | && __copy_from_user(&set.sig[1], &frame->extramask, | |
617 | sizeof(frame->extramask)))) | |
618 | goto badframe; | |
619 | ||
3982294b | 620 | set_current_blocked(&set); |
bfeb91a9 | 621 | |
6c25da5a AL |
622 | /* |
623 | * x86_32 has no uc_flags bits relevant to restore_sigcontext. | |
624 | * Save a few cycles by skipping the __get_user. | |
625 | */ | |
626 | if (restore_sigcontext(regs, &frame->sc, 0)) | |
bfeb91a9 | 627 | goto badframe; |
6a3713f0 | 628 | return regs->ax; |
bfeb91a9 HS |
629 | |
630 | badframe: | |
ae417bb4 | 631 | signal_fault(regs, frame, "sigreturn"); |
bfeb91a9 HS |
632 | |
633 | return 0; | |
634 | } | |
e5fa2d06 | 635 | #endif /* CONFIG_X86_32 */ |
bfeb91a9 | 636 | |
4c8ca51a | 637 | SYSCALL_DEFINE0(rt_sigreturn) |
bfeb91a9 | 638 | { |
3fe26fa3 | 639 | struct pt_regs *regs = current_pt_regs(); |
bfeb91a9 | 640 | struct rt_sigframe __user *frame; |
bfeb91a9 | 641 | sigset_t set; |
6c25da5a | 642 | unsigned long uc_flags; |
bfeb91a9 HS |
643 | |
644 | frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long)); | |
645 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
646 | goto badframe; | |
647 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
648 | goto badframe; | |
6c25da5a AL |
649 | if (__get_user(uc_flags, &frame->uc.uc_flags)) |
650 | goto badframe; | |
bfeb91a9 | 651 | |
e9bd3f0f | 652 | set_current_blocked(&set); |
bfeb91a9 | 653 | |
6c25da5a | 654 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
bfeb91a9 HS |
655 | goto badframe; |
656 | ||
c40702c4 | 657 | if (restore_altstack(&frame->uc.uc_stack)) |
bfeb91a9 HS |
658 | goto badframe; |
659 | ||
6a3713f0 | 660 | return regs->ax; |
bfeb91a9 HS |
661 | |
662 | badframe: | |
663 | signal_fault(regs, frame, "rt_sigreturn"); | |
664 | return 0; | |
665 | } | |
666 | ||
68463510 | 667 | static inline int is_ia32_compat_frame(struct ksignal *ksig) |
05012c13 | 668 | { |
97f2645f | 669 | return IS_ENABLED(CONFIG_IA32_EMULATION) && |
68463510 | 670 | ksig->ka.sa.sa_flags & SA_IA32_ABI; |
05012c13 IM |
671 | } |
672 | ||
68463510 | 673 | static inline int is_ia32_frame(struct ksignal *ksig) |
05012c13 | 674 | { |
68463510 | 675 | return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig); |
05012c13 IM |
676 | } |
677 | ||
68463510 | 678 | static inline int is_x32_frame(struct ksignal *ksig) |
05012c13 | 679 | { |
68463510 DS |
680 | return IS_ENABLED(CONFIG_X86_X32_ABI) && |
681 | ksig->ka.sa.sa_flags & SA_X32_ABI; | |
05012c13 IM |
682 | } |
683 | ||
1d13024e | 684 | static int |
235b8022 | 685 | setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) |
1d13024e | 686 | { |
3050a35f | 687 | int usig = ksig->sig; |
b7f9a11a | 688 | sigset_t *set = sigmask_to_save(); |
050902c0 | 689 | compat_sigset_t *cset = (compat_sigset_t *) set; |
1d13024e | 690 | |
d6761b8f MD |
691 | /* |
692 | * Increment event counter and perform fixup for the pre-signal | |
693 | * frame. | |
694 | */ | |
695 | rseq_signal_deliver(regs); | |
696 | ||
1d13024e | 697 | /* Set up the stack frame */ |
68463510 | 698 | if (is_ia32_frame(ksig)) { |
235b8022 AV |
699 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
700 | return ia32_setup_rt_frame(usig, ksig, cset, regs); | |
455edbc4 | 701 | else |
235b8022 | 702 | return ia32_setup_frame(usig, ksig, cset, regs); |
68463510 | 703 | } else if (is_x32_frame(ksig)) { |
235b8022 | 704 | return x32_setup_rt_frame(ksig, cset, regs); |
c5a37394 | 705 | } else { |
235b8022 | 706 | return __setup_rt_frame(ksig->sig, ksig, set, regs); |
c5a37394 | 707 | } |
1d13024e HS |
708 | } |
709 | ||
a610d6e6 | 710 | static void |
235b8022 | 711 | handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
1da177e4 | 712 | { |
fd0f86b6 | 713 | bool stepping, failed; |
c5bedc68 | 714 | struct fpu *fpu = ¤t->thread.fpu; |
fd0f86b6 | 715 | |
5ed92a8a BG |
716 | if (v8086_mode(regs)) |
717 | save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL); | |
718 | ||
1da177e4 | 719 | /* Are we from a system call? */ |
bb57925f | 720 | if (syscall_get_nr(current, regs) >= 0) { |
1da177e4 | 721 | /* If so, check system call restarting.. */ |
bb57925f | 722 | switch (syscall_get_error(current, regs)) { |
ac66f3fd HH |
723 | case -ERESTART_RESTARTBLOCK: |
724 | case -ERESTARTNOHAND: | |
725 | regs->ax = -EINTR; | |
726 | break; | |
727 | ||
728 | case -ERESTARTSYS: | |
235b8022 | 729 | if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { |
65ea5b03 | 730 | regs->ax = -EINTR; |
1da177e4 | 731 | break; |
ac66f3fd HH |
732 | } |
733 | /* fallthrough */ | |
734 | case -ERESTARTNOINTR: | |
735 | regs->ax = regs->orig_ax; | |
736 | regs->ip -= 2; | |
737 | break; | |
1da177e4 LT |
738 | } |
739 | } | |
740 | ||
741 | /* | |
fd0f86b6 ON |
742 | * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now |
743 | * so that register information in the sigcontext is correct and | |
744 | * then notify the tracer before entering the signal handler. | |
1da177e4 | 745 | */ |
fd0f86b6 ON |
746 | stepping = test_thread_flag(TIF_SINGLESTEP); |
747 | if (stepping) | |
748 | user_disable_single_step(current); | |
1da177e4 | 749 | |
235b8022 AV |
750 | failed = (setup_rt_frame(ksig, regs) < 0); |
751 | if (!failed) { | |
752 | /* | |
753 | * Clear the direction flag as per the ABI for function entry. | |
ddd40da4 | 754 | * |
24cda109 JO |
755 | * Clear RF when entering the signal handler, because |
756 | * it might disable possible debug exception from the | |
757 | * signal handler. | |
ddd40da4 | 758 | * |
fd0f86b6 ON |
759 | * Clear TF for the case when it wasn't set by debugger to |
760 | * avoid the recursive send_sigtrap() in SIGTRAP handler. | |
235b8022 | 761 | */ |
ddd40da4 | 762 | regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); |
66463db4 ON |
763 | /* |
764 | * Ensure the signal handler starts with the new fpu state. | |
765 | */ | |
e4a81bfc | 766 | if (fpu->initialized) |
fbce7782 | 767 | fpu__clear(fpu); |
a610d6e6 | 768 | } |
fd0f86b6 | 769 | signal_setup_done(failed, ksig, stepping); |
1da177e4 LT |
770 | } |
771 | ||
22eab110 DL |
772 | static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs) |
773 | { | |
609c19a3 AL |
774 | /* |
775 | * This function is fundamentally broken as currently | |
776 | * implemented. | |
777 | * | |
778 | * The idea is that we want to trigger a call to the | |
779 | * restart_block() syscall and that we want in_ia32_syscall(), | |
780 | * in_x32_syscall(), etc. to match whatever they were in the | |
781 | * syscall being restarted. We assume that the syscall | |
782 | * instruction at (regs->ip - 2) matches whatever syscall | |
783 | * instruction we used to enter in the first place. | |
784 | * | |
785 | * The problem is that we can get here when ptrace pokes | |
786 | * syscall-like values into regs even if we're not in a syscall | |
787 | * at all. | |
788 | * | |
789 | * For now, we maintain historical behavior and guess based on | |
790 | * stored state. We could do better by saving the actual | |
791 | * syscall arch in restart_block or (with caveats on x32) by | |
792 | * checking if regs->ip points to 'int $0x80'. The current | |
793 | * behavior is incorrect if a tracer has a different bitness | |
794 | * than the tracee. | |
795 | */ | |
796 | #ifdef CONFIG_IA32_EMULATION | |
37a8f7c3 | 797 | if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED)) |
95d97adb DL |
798 | return __NR_ia32_restart_syscall; |
799 | #endif | |
800 | #ifdef CONFIG_X86_X32_ABI | |
801 | return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT); | |
802 | #else | |
22eab110 | 803 | return __NR_restart_syscall; |
95d97adb | 804 | #endif |
22eab110 | 805 | } |
57917752 | 806 | |
1da177e4 LT |
807 | /* |
808 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
809 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
810 | * mistake. | |
811 | */ | |
1f484aa6 | 812 | void do_signal(struct pt_regs *regs) |
1da177e4 | 813 | { |
235b8022 | 814 | struct ksignal ksig; |
1da177e4 | 815 | |
235b8022 | 816 | if (get_signal(&ksig)) { |
7e907f48 | 817 | /* Whee! Actually deliver the signal. */ |
235b8022 | 818 | handle_signal(&ksig, regs); |
283828f3 | 819 | return; |
1da177e4 LT |
820 | } |
821 | ||
1da177e4 | 822 | /* Did we come from a system call? */ |
bb57925f | 823 | if (syscall_get_nr(current, regs) >= 0) { |
1da177e4 | 824 | /* Restart the system call - no handlers present */ |
bb57925f | 825 | switch (syscall_get_error(current, regs)) { |
283828f3 DH |
826 | case -ERESTARTNOHAND: |
827 | case -ERESTARTSYS: | |
828 | case -ERESTARTNOINTR: | |
65ea5b03 PA |
829 | regs->ax = regs->orig_ax; |
830 | regs->ip -= 2; | |
283828f3 DH |
831 | break; |
832 | ||
833 | case -ERESTART_RESTARTBLOCK: | |
22eab110 | 834 | regs->ax = get_nr_restart_syscall(regs); |
65ea5b03 | 835 | regs->ip -= 2; |
283828f3 | 836 | break; |
1da177e4 LT |
837 | } |
838 | } | |
283828f3 | 839 | |
ac66f3fd HH |
840 | /* |
841 | * If there's no signal to deliver, we just put the saved sigmask | |
842 | * back. | |
843 | */ | |
51a7b448 | 844 | restore_saved_sigmask(); |
1da177e4 LT |
845 | } |
846 | ||
72fa50f4 HS |
847 | void signal_fault(struct pt_regs *regs, void __user *frame, char *where) |
848 | { | |
849 | struct task_struct *me = current; | |
850 | ||
851 | if (show_unhandled_signals && printk_ratelimit()) { | |
ae417bb4 | 852 | printk("%s" |
72fa50f4 | 853 | "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", |
ae417bb4 | 854 | task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, |
72fa50f4 HS |
855 | me->comm, me->pid, where, frame, |
856 | regs->ip, regs->sp, regs->orig_ax); | |
1c99a687 | 857 | print_vma_addr(KERN_CONT " in ", regs->ip); |
c767a54b | 858 | pr_cont("\n"); |
72fa50f4 HS |
859 | } |
860 | ||
861 | force_sig(SIGSEGV, me); | |
862 | } | |
c5a37394 PA |
863 | |
864 | #ifdef CONFIG_X86_X32_ABI | |
3fe26fa3 | 865 | asmlinkage long sys32_x32_rt_sigreturn(void) |
c5a37394 | 866 | { |
3fe26fa3 | 867 | struct pt_regs *regs = current_pt_regs(); |
c5a37394 PA |
868 | struct rt_sigframe_x32 __user *frame; |
869 | sigset_t set; | |
6c25da5a | 870 | unsigned long uc_flags; |
c5a37394 PA |
871 | |
872 | frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); | |
873 | ||
874 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
875 | goto badframe; | |
876 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
877 | goto badframe; | |
6c25da5a AL |
878 | if (__get_user(uc_flags, &frame->uc.uc_flags)) |
879 | goto badframe; | |
c5a37394 | 880 | |
c5a37394 PA |
881 | set_current_blocked(&set); |
882 | ||
6c25da5a | 883 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
c5a37394 PA |
884 | goto badframe; |
885 | ||
90268439 | 886 | if (compat_restore_altstack(&frame->uc.uc_stack)) |
c5a37394 PA |
887 | goto badframe; |
888 | ||
6a3713f0 | 889 | return regs->ax; |
c5a37394 PA |
890 | |
891 | badframe: | |
892 | signal_fault(regs, frame, "x32 rt_sigreturn"); | |
893 | return 0; | |
894 | } | |
895 | #endif |