1 /* 2 * Based on arch/arm/kernel/signal.c 3 * 4 * Copyright (C) 1995-2009 Russell King 5 * Copyright (C) 2012 ARM Ltd. 6 * Modified by Will Deacon <will.deacon@arm.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program. If not, see <http://www.gnu.org/licenses/>. 19 */ 20 21 #include <linux/compat.h> 22 #include <linux/signal.h> 23 #include <linux/syscalls.h> 24 #include <linux/ratelimit.h> 25 26 #include <asm/fpsimd.h> 27 #include <asm/signal32.h> 28 #include <asm/uaccess.h> 29 #include <asm/unistd32.h> 30 31 struct compat_sigcontext { 32 /* We always set these two fields to 0 */ 33 compat_ulong_t trap_no; 34 compat_ulong_t error_code; 35 36 compat_ulong_t oldmask; 37 compat_ulong_t arm_r0; 38 compat_ulong_t arm_r1; 39 compat_ulong_t arm_r2; 40 compat_ulong_t arm_r3; 41 compat_ulong_t arm_r4; 42 compat_ulong_t arm_r5; 43 compat_ulong_t arm_r6; 44 compat_ulong_t arm_r7; 45 compat_ulong_t arm_r8; 46 compat_ulong_t arm_r9; 47 compat_ulong_t arm_r10; 48 compat_ulong_t arm_fp; 49 compat_ulong_t arm_ip; 50 compat_ulong_t arm_sp; 51 compat_ulong_t arm_lr; 52 compat_ulong_t arm_pc; 53 compat_ulong_t arm_cpsr; 54 compat_ulong_t fault_address; 55 }; 56 57 struct compat_ucontext { 58 compat_ulong_t uc_flags; 59 compat_uptr_t uc_link; 60 compat_stack_t uc_stack; 61 struct compat_sigcontext uc_mcontext; 62 compat_sigset_t uc_sigmask; 63 int __unused[32 - (sizeof (compat_sigset_t) / sizeof (int))]; 64 compat_ulong_t uc_regspace[128] __attribute__((__aligned__(8))); 65 }; 66 67 struct compat_vfp_sigframe { 68 compat_ulong_t magic; 69 compat_ulong_t size; 70 struct compat_user_vfp { 71 compat_u64 fpregs[32]; 72 compat_ulong_t fpscr; 73 } ufp; 74 struct compat_user_vfp_exc { 75 compat_ulong_t fpexc; 76 compat_ulong_t fpinst; 77 compat_ulong_t fpinst2; 78 } ufp_exc; 79 } __attribute__((__aligned__(8))); 80 81 #define VFP_MAGIC 0x56465001 82 #define VFP_STORAGE_SIZE sizeof(struct compat_vfp_sigframe) 83 84 struct compat_aux_sigframe { 85 struct compat_vfp_sigframe vfp; 86 87 /* Something that isn't a valid magic number for any coprocessor. */ 88 unsigned long end_magic; 89 } __attribute__((__aligned__(8))); 90 91 struct compat_sigframe { 92 struct compat_ucontext uc; 93 compat_ulong_t retcode[2]; 94 }; 95 96 struct compat_rt_sigframe { 97 struct compat_siginfo info; 98 struct compat_sigframe sig; 99 }; 100 101 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 102 103 static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set) 104 { 105 compat_sigset_t cset; 106 107 cset.sig[0] = set->sig[0] & 0xffffffffull; 108 cset.sig[1] = set->sig[0] >> 32; 109 110 return copy_to_user(uset, &cset, sizeof(*uset)); 111 } 112 113 static inline int get_sigset_t(sigset_t *set, 114 const compat_sigset_t __user *uset) 115 { 116 compat_sigset_t s32; 117 118 if (copy_from_user(&s32, uset, sizeof(*uset))) 119 return -EFAULT; 120 121 set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32); 122 return 0; 123 } 124 125 int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from) 126 { 127 int err; 128 129 if (!access_ok(VERIFY_WRITE, to, sizeof(*to))) 130 return -EFAULT; 131 132 /* If you change siginfo_t structure, please be sure 133 * this code is fixed accordingly. 134 * It should never copy any pad contained in the structure 135 * to avoid security leaks, but must copy the generic 136 * 3 ints plus the relevant union member. 137 * This routine must convert siginfo from 64bit to 32bit as well 138 * at the same time. 139 */ 140 err = __put_user(from->si_signo, &to->si_signo); 141 err |= __put_user(from->si_errno, &to->si_errno); 142 err |= __put_user((short)from->si_code, &to->si_code); 143 if (from->si_code < 0) 144 err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, 145 SI_PAD_SIZE); 146 else switch (from->si_code & __SI_MASK) { 147 case __SI_KILL: 148 err |= __put_user(from->si_pid, &to->si_pid); 149 err |= __put_user(from->si_uid, &to->si_uid); 150 break; 151 case __SI_TIMER: 152 err |= __put_user(from->si_tid, &to->si_tid); 153 err |= __put_user(from->si_overrun, &to->si_overrun); 154 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, 155 &to->si_ptr); 156 break; 157 case __SI_POLL: 158 err |= __put_user(from->si_band, &to->si_band); 159 err |= __put_user(from->si_fd, &to->si_fd); 160 break; 161 case __SI_FAULT: 162 err |= __put_user((compat_uptr_t)(unsigned long)from->si_addr, 163 &to->si_addr); 164 #ifdef BUS_MCEERR_AO 165 /* 166 * Other callers might not initialize the si_lsb field, 167 * so check explicitely for the right codes here. 168 */ 169 if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) 170 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); 171 #endif 172 break; 173 case __SI_CHLD: 174 err |= __put_user(from->si_pid, &to->si_pid); 175 err |= __put_user(from->si_uid, &to->si_uid); 176 err |= __put_user(from->si_status, &to->si_status); 177 err |= __put_user(from->si_utime, &to->si_utime); 178 err |= __put_user(from->si_stime, &to->si_stime); 179 break; 180 case __SI_RT: /* This is not generated by the kernel as of now. */ 181 case __SI_MESGQ: /* But this is */ 182 err |= __put_user(from->si_pid, &to->si_pid); 183 err |= __put_user(from->si_uid, &to->si_uid); 184 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr); 185 break; 186 default: /* this is just in case for now ... */ 187 err |= __put_user(from->si_pid, &to->si_pid); 188 err |= __put_user(from->si_uid, &to->si_uid); 189 break; 190 } 191 return err; 192 } 193 194 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from) 195 { 196 memset(to, 0, sizeof *to); 197 198 if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) || 199 copy_from_user(to->_sifields._pad, 200 from->_sifields._pad, SI_PAD_SIZE)) 201 return -EFAULT; 202 203 return 0; 204 } 205 206 /* 207 * VFP save/restore code. 208 */ 209 static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) 210 { 211 struct fpsimd_state *fpsimd = ¤t->thread.fpsimd_state; 212 compat_ulong_t magic = VFP_MAGIC; 213 compat_ulong_t size = VFP_STORAGE_SIZE; 214 compat_ulong_t fpscr, fpexc; 215 int err = 0; 216 217 /* 218 * Save the hardware registers to the fpsimd_state structure. 219 * Note that this also saves V16-31, which aren't visible 220 * in AArch32. 221 */ 222 fpsimd_save_state(fpsimd); 223 224 /* Place structure header on the stack */ 225 __put_user_error(magic, &frame->magic, err); 226 __put_user_error(size, &frame->size, err); 227 228 /* 229 * Now copy the FP registers. Since the registers are packed, 230 * we can copy the prefix we want (V0-V15) as it is. 231 * FIXME: Won't work if big endian. 232 */ 233 err |= __copy_to_user(&frame->ufp.fpregs, fpsimd->vregs, 234 sizeof(frame->ufp.fpregs)); 235 236 /* Create an AArch32 fpscr from the fpsr and the fpcr. */ 237 fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) | 238 (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK); 239 __put_user_error(fpscr, &frame->ufp.fpscr, err); 240 241 /* 242 * The exception register aren't available so we fake up a 243 * basic FPEXC and zero everything else. 244 */ 245 fpexc = (1 << 30); 246 __put_user_error(fpexc, &frame->ufp_exc.fpexc, err); 247 __put_user_error(0, &frame->ufp_exc.fpinst, err); 248 __put_user_error(0, &frame->ufp_exc.fpinst2, err); 249 250 return err ? -EFAULT : 0; 251 } 252 253 static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) 254 { 255 struct fpsimd_state fpsimd; 256 compat_ulong_t magic = VFP_MAGIC; 257 compat_ulong_t size = VFP_STORAGE_SIZE; 258 compat_ulong_t fpscr; 259 int err = 0; 260 261 __get_user_error(magic, &frame->magic, err); 262 __get_user_error(size, &frame->size, err); 263 264 if (err) 265 return -EFAULT; 266 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) 267 return -EINVAL; 268 269 /* 270 * Copy the FP registers into the start of the fpsimd_state. 271 * FIXME: Won't work if big endian. 272 */ 273 err |= __copy_from_user(fpsimd.vregs, frame->ufp.fpregs, 274 sizeof(frame->ufp.fpregs)); 275 276 /* Extract the fpsr and the fpcr from the fpscr */ 277 __get_user_error(fpscr, &frame->ufp.fpscr, err); 278 fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK; 279 fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK; 280 281 /* 282 * We don't need to touch the exception register, so 283 * reload the hardware state. 284 */ 285 if (!err) { 286 preempt_disable(); 287 fpsimd_load_state(&fpsimd); 288 preempt_enable(); 289 } 290 291 return err ? -EFAULT : 0; 292 } 293 294 static int compat_restore_sigframe(struct pt_regs *regs, 295 struct compat_sigframe __user *sf) 296 { 297 int err; 298 sigset_t set; 299 struct compat_aux_sigframe __user *aux; 300 301 err = get_sigset_t(&set, &sf->uc.uc_sigmask); 302 if (err == 0) { 303 sigdelsetmask(&set, ~_BLOCKABLE); 304 set_current_blocked(&set); 305 } 306 307 __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); 308 __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); 309 __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); 310 __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); 311 __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); 312 __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); 313 __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); 314 __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); 315 __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); 316 __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); 317 __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); 318 __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); 319 __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); 320 __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); 321 __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); 322 __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); 323 __get_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err); 324 325 /* 326 * Avoid compat_sys_sigreturn() restarting. 327 */ 328 regs->syscallno = ~0UL; 329 330 err |= !valid_user_regs(®s->user_regs); 331 332 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; 333 if (err == 0) 334 err |= compat_restore_vfp_context(&aux->vfp); 335 336 return err; 337 } 338 339 asmlinkage int compat_sys_sigreturn(struct pt_regs *regs) 340 { 341 struct compat_sigframe __user *frame; 342 343 /* Always make any pending restarted system calls return -EINTR */ 344 current_thread_info()->restart_block.fn = do_no_restart_syscall; 345 346 /* 347 * Since we stacked the signal on a 64-bit boundary, 348 * then 'sp' should be word aligned here. If it's 349 * not, then the user is trying to mess with us. 350 */ 351 if (regs->compat_sp & 7) 352 goto badframe; 353 354 frame = (struct compat_sigframe __user *)regs->compat_sp; 355 356 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 357 goto badframe; 358 359 if (compat_restore_sigframe(regs, frame)) 360 goto badframe; 361 362 return regs->regs[0]; 363 364 badframe: 365 if (show_unhandled_signals) 366 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n", 367 current->comm, task_pid_nr(current), __func__, 368 regs->pc, regs->sp); 369 force_sig(SIGSEGV, current); 370 return 0; 371 } 372 373 asmlinkage int compat_sys_rt_sigreturn(struct pt_regs *regs) 374 { 375 struct compat_rt_sigframe __user *frame; 376 377 /* Always make any pending restarted system calls return -EINTR */ 378 current_thread_info()->restart_block.fn = do_no_restart_syscall; 379 380 /* 381 * Since we stacked the signal on a 64-bit boundary, 382 * then 'sp' should be word aligned here. If it's 383 * not, then the user is trying to mess with us. 384 */ 385 if (regs->compat_sp & 7) 386 goto badframe; 387 388 frame = (struct compat_rt_sigframe __user *)regs->compat_sp; 389 390 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 391 goto badframe; 392 393 if (compat_restore_sigframe(regs, &frame->sig)) 394 goto badframe; 395 396 if (compat_restore_altstack(&frame->sig.uc.uc_stack)) 397 goto badframe; 398 399 return regs->regs[0]; 400 401 badframe: 402 if (show_unhandled_signals) 403 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n", 404 current->comm, task_pid_nr(current), __func__, 405 regs->pc, regs->sp); 406 force_sig(SIGSEGV, current); 407 return 0; 408 } 409 410 static void __user *compat_get_sigframe(struct k_sigaction *ka, 411 struct pt_regs *regs, 412 int framesize) 413 { 414 compat_ulong_t sp = regs->compat_sp; 415 void __user *frame; 416 417 /* 418 * This is the X/Open sanctioned signal stack switching. 419 */ 420 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) 421 sp = current->sas_ss_sp + current->sas_ss_size; 422 423 /* 424 * ATPCS B01 mandates 8-byte alignment 425 */ 426 frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7)); 427 428 /* 429 * Check that we can actually write to the signal frame. 430 */ 431 if (!access_ok(VERIFY_WRITE, frame, framesize)) 432 frame = NULL; 433 434 return frame; 435 } 436 437 static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, 438 compat_ulong_t __user *rc, void __user *frame, 439 int usig) 440 { 441 compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler); 442 compat_ulong_t retcode; 443 compat_ulong_t spsr = regs->pstate & ~PSR_f; 444 int thumb; 445 446 /* Check if the handler is written for ARM or Thumb */ 447 thumb = handler & 1; 448 449 if (thumb) 450 spsr |= COMPAT_PSR_T_BIT; 451 else 452 spsr &= ~COMPAT_PSR_T_BIT; 453 454 /* The IT state must be cleared for both ARM and Thumb-2 */ 455 spsr &= ~COMPAT_PSR_IT_MASK; 456 457 if (ka->sa.sa_flags & SA_RESTORER) { 458 retcode = ptr_to_compat(ka->sa.sa_restorer); 459 } else { 460 /* Set up sigreturn pointer */ 461 unsigned int idx = thumb << 1; 462 463 if (ka->sa.sa_flags & SA_SIGINFO) 464 idx += 3; 465 466 retcode = AARCH32_VECTORS_BASE + 467 AARCH32_KERN_SIGRET_CODE_OFFSET + 468 (idx << 2) + thumb; 469 } 470 471 regs->regs[0] = usig; 472 regs->compat_sp = ptr_to_compat(frame); 473 regs->compat_lr = retcode; 474 regs->pc = handler; 475 regs->pstate = spsr; 476 } 477 478 static int compat_setup_sigframe(struct compat_sigframe __user *sf, 479 struct pt_regs *regs, sigset_t *set) 480 { 481 struct compat_aux_sigframe __user *aux; 482 int err = 0; 483 484 __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); 485 __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); 486 __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); 487 __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); 488 __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); 489 __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); 490 __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); 491 __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); 492 __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); 493 __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); 494 __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); 495 __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); 496 __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); 497 __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); 498 __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); 499 __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); 500 __put_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err); 501 502 __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err); 503 __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.error_code, err); 504 __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err); 505 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 506 507 err |= put_sigset_t(&sf->uc.uc_sigmask, set); 508 509 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; 510 511 if (err == 0) 512 err |= compat_preserve_vfp_context(&aux->vfp); 513 __put_user_error(0, &aux->end_magic, err); 514 515 return err; 516 } 517 518 /* 519 * 32-bit signal handling routines called from signal.c 520 */ 521 int compat_setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, 522 sigset_t *set, struct pt_regs *regs) 523 { 524 struct compat_rt_sigframe __user *frame; 525 int err = 0; 526 527 frame = compat_get_sigframe(ka, regs, sizeof(*frame)); 528 529 if (!frame) 530 return 1; 531 532 err |= copy_siginfo_to_user32(&frame->info, info); 533 534 __put_user_error(0, &frame->sig.uc.uc_flags, err); 535 __put_user_error(0, &frame->sig.uc.uc_link, err); 536 537 err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp); 538 539 err |= compat_setup_sigframe(&frame->sig, regs, set); 540 541 if (err == 0) { 542 compat_setup_return(regs, ka, frame->sig.retcode, frame, usig); 543 regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info; 544 regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc; 545 } 546 547 return err; 548 } 549 550 int compat_setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, 551 struct pt_regs *regs) 552 { 553 struct compat_sigframe __user *frame; 554 int err = 0; 555 556 frame = compat_get_sigframe(ka, regs, sizeof(*frame)); 557 558 if (!frame) 559 return 1; 560 561 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 562 563 err |= compat_setup_sigframe(frame, regs, set); 564 if (err == 0) 565 compat_setup_return(regs, ka, frame->retcode, frame, usig); 566 567 return err; 568 } 569 570 void compat_setup_restart_syscall(struct pt_regs *regs) 571 { 572 regs->regs[7] = __NR_compat_restart_syscall; 573 } 574