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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 | // SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 1991, 1992 Linus Torvalds * * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes * 2000-12-* x86-64 compatibility mode signal handling by Andi Kleen */ #include <linux/sched.h> #include <linux/sched/task_stack.h> #include <linux/mm.h> #include <linux/smp.h> #include <linux/kernel.h> #include <linux/errno.h> #include <linux/wait.h> #include <linux/unistd.h> #include <linux/stddef.h> #include <linux/personality.h> #include <linux/compat.h> #include <linux/binfmts.h> #include <linux/syscalls.h> #include <asm/ucontext.h> #include <linux/uaccess.h> #include <asm/fpu/signal.h> #include <asm/ptrace.h> #include <asm/user32.h> #include <uapi/asm/sigcontext.h> #include <asm/proto.h> #include <asm/vdso.h> #include <asm/sigframe.h> #include <asm/sighandling.h> #include <asm/smap.h> #include <asm/gsseg.h> #ifdef CONFIG_IA32_EMULATION #include <asm/unistd_32_ia32.h> static inline void reload_segments(struct sigcontext_32 *sc) { unsigned int cur; savesegment(gs, cur); if ((sc->gs | 0x03) != cur) load_gs_index(sc->gs | 0x03); savesegment(fs, cur); if ((sc->fs | 0x03) != cur) loadsegment(fs, sc->fs | 0x03); savesegment(ds, cur); if ((sc->ds | 0x03) != cur) loadsegment(ds, sc->ds | 0x03); savesegment(es, cur); if ((sc->es | 0x03) != cur) loadsegment(es, sc->es | 0x03); } #define sigset32_t compat_sigset_t #define siginfo32_t compat_siginfo_t #define restore_altstack32 compat_restore_altstack #define unsafe_save_altstack32 unsafe_compat_save_altstack #else #define sigset32_t sigset_t #define siginfo32_t siginfo_t #define __NR_ia32_sigreturn __NR_sigreturn #define __NR_ia32_rt_sigreturn __NR_rt_sigreturn #define restore_altstack32 restore_altstack #define unsafe_save_altstack32 unsafe_save_altstack #define __copy_siginfo_to_user32 copy_siginfo_to_user #endif /* * Do a signal return; undo the signal stack. */ static bool ia32_restore_sigcontext(struct pt_regs *regs, struct sigcontext_32 __user *usc) { struct sigcontext_32 sc; /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall; if (unlikely(copy_from_user(&sc, usc, sizeof(sc)))) return false; /* Get only the ia32 registers. */ regs->bx = sc.bx; regs->cx = sc.cx; regs->dx = sc.dx; regs->si = sc.si; regs->di = sc.di; regs->bp = sc.bp; regs->ax = sc.ax; regs->sp = sc.sp; regs->ip = sc.ip; /* Get CS/SS and force CPL3 */ regs->cs = sc.cs | 0x03; regs->ss = sc.ss | 0x03; regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS); /* disable syscall checks */ regs->orig_ax = -1; #ifdef CONFIG_IA32_EMULATION /* * Reload fs and gs if they have changed in the signal * handler. This does not handle long fs/gs base changes in * the handler, but does not clobber them at least in the * normal case. */ reload_segments(&sc); #else loadsegment(gs, sc.gs); regs->fs = sc.fs; regs->es = sc.es; regs->ds = sc.ds; #endif return fpu__restore_sig(compat_ptr(sc.fpstate), 1); } SYSCALL32_DEFINE0(sigreturn) { struct pt_regs *regs = current_pt_regs(); struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8); sigset_t set; if (!access_ok(frame, sizeof(*frame))) goto badframe; if (__get_user(set.sig[0], &frame->sc.oldmask) || __get_user(((__u32 *)&set)[1], &frame->extramask[0])) goto badframe; set_current_blocked(&set); if (!ia32_restore_sigcontext(regs, &frame->sc)) goto badframe; return regs->ax; badframe: signal_fault(regs, frame, "32bit sigreturn"); return 0; } SYSCALL32_DEFINE0(rt_sigreturn) { struct pt_regs *regs = current_pt_regs(); struct rt_sigframe_ia32 __user *frame; sigset_t set; frame = (struct rt_sigframe_ia32 __user *)(regs->sp - 4); if (!access_ok(frame, sizeof(*frame))) goto badframe; if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask)) goto badframe; set_current_blocked(&set); if (!ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext)) goto badframe; if (restore_altstack32(&frame->uc.uc_stack)) goto badframe; return regs->ax; badframe: signal_fault(regs, frame, "32bit rt sigreturn"); return 0; } /* * Set up a signal frame. */ #define get_user_seg(seg) ({ unsigned int v; savesegment(seg, v); v; }) static __always_inline int __unsafe_setup_sigcontext32(struct sigcontext_32 __user *sc, void __user *fpstate, struct pt_regs *regs, unsigned int mask) { unsafe_put_user(get_user_seg(gs), (unsigned int __user *)&sc->gs, Efault); #ifdef CONFIG_IA32_EMULATION unsafe_put_user(get_user_seg(fs), (unsigned int __user *)&sc->fs, Efault); unsafe_put_user(get_user_seg(ds), (unsigned int __user *)&sc->ds, Efault); unsafe_put_user(get_user_seg(es), (unsigned int __user *)&sc->es, Efault); #else unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault); unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault); unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault); #endif unsafe_put_user(regs->di, &sc->di, Efault); unsafe_put_user(regs->si, &sc->si, Efault); unsafe_put_user(regs->bp, &sc->bp, Efault); unsafe_put_user(regs->sp, &sc->sp, Efault); unsafe_put_user(regs->bx, &sc->bx, Efault); unsafe_put_user(regs->dx, &sc->dx, Efault); unsafe_put_user(regs->cx, &sc->cx, Efault); unsafe_put_user(regs->ax, &sc->ax, Efault); unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault); unsafe_put_user(current->thread.error_code, &sc->err, Efault); unsafe_put_user(regs->ip, &sc->ip, Efault); unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault); unsafe_put_user(regs->flags, &sc->flags, Efault); unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault); unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault); unsafe_put_user(ptr_to_compat(fpstate), &sc->fpstate, Efault); /* non-iBCS2 extensions.. */ unsafe_put_user(mask, &sc->oldmask, Efault); unsafe_put_user(current->thread.cr2, &sc->cr2, Efault); return 0; Efault: return -EFAULT; } #define unsafe_put_sigcontext32(sc, fp, regs, set, label) \ do { \ if (__unsafe_setup_sigcontext32(sc, fp, regs, set->sig[0])) \ goto label; \ } while(0) int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs) { sigset32_t *set = (sigset32_t *) sigmask_to_save(); struct sigframe_ia32 __user *frame; void __user *restorer; void __user *fp = NULL; /* copy_to_user optimizes that into a single 8 byte store */ static const struct { u16 poplmovl; u32 val; u16 int80; } __attribute__((packed)) code = { 0xb858, /* popl %eax ; movl $...,%eax */ __NR_ia32_sigreturn, 0x80cd, /* int $0x80 */ }; frame = get_sigframe(ksig, regs, sizeof(*frame), &fp); if (ksig->ka.sa.sa_flags & SA_RESTORER) { restorer = ksig->ka.sa.sa_restorer; } else { /* Return stub is in 32bit vsyscall page */ if (current->mm->context.vdso) restorer = current->mm->context.vdso + vdso_image_32.sym___kernel_sigreturn; else restorer = &frame->retcode; } if (!user_access_begin(frame, sizeof(*frame))) return -EFAULT; unsafe_put_user(ksig->sig, &frame->sig, Efault); unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault); unsafe_put_user(set->sig[1], &frame->extramask[0], Efault); unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault); /* * These are actually not used anymore, but left because some * gdb versions depend on them as a marker. */ unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault); user_access_end(); /* Set up registers for signal handler */ regs->sp = (unsigned long) frame; regs->ip = (unsigned long) ksig->ka.sa.sa_handler; /* Make -mregparm=3 work */ regs->ax = ksig->sig; regs->dx = 0; regs->cx = 0; #ifdef CONFIG_IA32_EMULATION loadsegment(ds, __USER_DS); loadsegment(es, __USER_DS); #else regs->ds = __USER_DS; regs->es = __USER_DS; #endif regs->cs = __USER32_CS; regs->ss = __USER_DS; return 0; Efault: user_access_end(); return -EFAULT; } int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) { sigset32_t *set = (sigset32_t *) sigmask_to_save(); struct rt_sigframe_ia32 __user *frame; void __user *restorer; void __user *fp = NULL; /* unsafe_put_user optimizes that into a single 8 byte store */ static const struct { u8 movl; u32 val; u16 int80; u8 pad; } __attribute__((packed)) code = { 0xb8, __NR_ia32_rt_sigreturn, 0x80cd, 0, }; frame = get_sigframe(ksig, regs, sizeof(*frame), &fp); if (!user_access_begin(frame, sizeof(*frame))) return -EFAULT; unsafe_put_user(ksig->sig, &frame->sig, Efault); unsafe_put_user(ptr_to_compat(&frame->info), &frame->pinfo, Efault); unsafe_put_user(ptr_to_compat(&frame->uc), &frame->puc, Efault); /* Create the ucontext. */ if (static_cpu_has(X86_FEATURE_XSAVE)) unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault); else unsafe_put_user(0, &frame->uc.uc_flags, Efault); unsafe_put_user(0, &frame->uc.uc_link, Efault); unsafe_save_altstack32(&frame->uc.uc_stack, regs->sp, Efault); if (ksig->ka.sa.sa_flags & SA_RESTORER) restorer = ksig->ka.sa.sa_restorer; else restorer = current->mm->context.vdso + vdso_image_32.sym___kernel_rt_sigreturn; unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault); /* * Not actually used anymore, but left because some gdb * versions need it. */ unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault); unsafe_put_sigcontext32(&frame->uc.uc_mcontext, fp, regs, set, Efault); unsafe_put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask, Efault); user_access_end(); if (__copy_siginfo_to_user32(&frame->info, &ksig->info)) return -EFAULT; /* Set up registers for signal handler */ regs->sp = (unsigned long) frame; regs->ip = (unsigned long) ksig->ka.sa.sa_handler; /* Make -mregparm=3 work */ regs->ax = ksig->sig; regs->dx = (unsigned long) &frame->info; regs->cx = (unsigned long) &frame->uc; #ifdef CONFIG_IA32_EMULATION loadsegment(ds, __USER_DS); loadsegment(es, __USER_DS); #else regs->ds = __USER_DS; regs->es = __USER_DS; #endif regs->cs = __USER32_CS; regs->ss = __USER_DS; return 0; Efault: user_access_end(); return -EFAULT; } /* * The siginfo_t structure and handing code is very easy * to break in several ways. It must always be updated when new * updates are made to the main siginfo_t, and * copy_siginfo_to_user32() must be updated when the * (arch-independent) copy_siginfo_to_user() is updated. * * It is also easy to put a new member in the siginfo_t * which has implicit alignment which can move internal structure * alignment around breaking the ABI. This can happen if you, * for instance, put a plain 64-bit value in there. */ /* * If adding a new si_code, there is probably new data in * the siginfo. Make sure folks bumping the si_code * limits also have to look at this code. Make sure any * new fields are handled in copy_siginfo_to_user32()! */ static_assert(NSIGILL == 11); static_assert(NSIGFPE == 15); static_assert(NSIGSEGV == 10); static_assert(NSIGBUS == 5); static_assert(NSIGTRAP == 6); static_assert(NSIGCHLD == 6); static_assert(NSIGSYS == 2); /* This is part of the ABI and can never change in size: */ static_assert(sizeof(siginfo32_t) == 128); /* This is a part of the ABI and can never change in alignment */ static_assert(__alignof__(siginfo32_t) == 4); /* * The offsets of all the (unioned) si_fields are fixed * in the ABI, of course. Make sure none of them ever * move and are always at the beginning: */ static_assert(offsetof(siginfo32_t, _sifields) == 3 * sizeof(int)); static_assert(offsetof(siginfo32_t, si_signo) == 0); static_assert(offsetof(siginfo32_t, si_errno) == 4); static_assert(offsetof(siginfo32_t, si_code) == 8); /* * Ensure that the size of each si_field never changes. * If it does, it is a sign that the * copy_siginfo_to_user32() code below needs to updated * along with the size in the CHECK_SI_SIZE(). * * We repeat this check for both the generic and compat * siginfos. * * Note: it is OK for these to grow as long as the whole * structure stays within the padding size (checked * above). */ #define CHECK_SI_OFFSET(name) \ static_assert(offsetof(siginfo32_t, _sifields) == \ offsetof(siginfo32_t, _sifields.name)) #define CHECK_SI_SIZE(name, size) \ static_assert(sizeof_field(siginfo32_t, _sifields.name) == size) CHECK_SI_OFFSET(_kill); CHECK_SI_SIZE (_kill, 2*sizeof(int)); static_assert(offsetof(siginfo32_t, si_pid) == 0xC); static_assert(offsetof(siginfo32_t, si_uid) == 0x10); CHECK_SI_OFFSET(_timer); #ifdef CONFIG_COMPAT /* compat_siginfo_t doesn't have si_sys_private */ CHECK_SI_SIZE (_timer, 3*sizeof(int)); #else CHECK_SI_SIZE (_timer, 4*sizeof(int)); #endif static_assert(offsetof(siginfo32_t, si_tid) == 0x0C); static_assert(offsetof(siginfo32_t, si_overrun) == 0x10); static_assert(offsetof(siginfo32_t, si_value) == 0x14); CHECK_SI_OFFSET(_rt); CHECK_SI_SIZE (_rt, 3*sizeof(int)); static_assert(offsetof(siginfo32_t, si_pid) == 0x0C); static_assert(offsetof(siginfo32_t, si_uid) == 0x10); static_assert(offsetof(siginfo32_t, si_value) == 0x14); CHECK_SI_OFFSET(_sigchld); CHECK_SI_SIZE (_sigchld, 5*sizeof(int)); static_assert(offsetof(siginfo32_t, si_pid) == 0x0C); static_assert(offsetof(siginfo32_t, si_uid) == 0x10); static_assert(offsetof(siginfo32_t, si_status) == 0x14); static_assert(offsetof(siginfo32_t, si_utime) == 0x18); static_assert(offsetof(siginfo32_t, si_stime) == 0x1C); CHECK_SI_OFFSET(_sigfault); CHECK_SI_SIZE (_sigfault, 4*sizeof(int)); static_assert(offsetof(siginfo32_t, si_addr) == 0x0C); static_assert(offsetof(siginfo32_t, si_trapno) == 0x10); static_assert(offsetof(siginfo32_t, si_addr_lsb) == 0x10); static_assert(offsetof(siginfo32_t, si_lower) == 0x14); static_assert(offsetof(siginfo32_t, si_upper) == 0x18); static_assert(offsetof(siginfo32_t, si_pkey) == 0x14); static_assert(offsetof(siginfo32_t, si_perf_data) == 0x10); static_assert(offsetof(siginfo32_t, si_perf_type) == 0x14); static_assert(offsetof(siginfo32_t, si_perf_flags) == 0x18); CHECK_SI_OFFSET(_sigpoll); CHECK_SI_SIZE (_sigpoll, 2*sizeof(int)); static_assert(offsetof(siginfo32_t, si_band) == 0x0C); static_assert(offsetof(siginfo32_t, si_fd) == 0x10); CHECK_SI_OFFSET(_sigsys); CHECK_SI_SIZE (_sigsys, 3*sizeof(int)); static_assert(offsetof(siginfo32_t, si_call_addr) == 0x0C); static_assert(offsetof(siginfo32_t, si_syscall) == 0x10); static_assert(offsetof(siginfo32_t, si_arch) == 0x14); /* any new si_fields should be added here */ |