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/esr.h> 27 #include <asm/fpsimd.h> 28 #include <asm/signal32.h> 29 #include <asm/uaccess.h> 30 #include <asm/unistd32.h> 31 32 struct compat_sigcontext { 33 /* We always set these two fields to 0 */ 34 compat_ulong_t trap_no; 35 compat_ulong_t error_code; 36 37 compat_ulong_t oldmask; 38 compat_ulong_t arm_r0; 39 compat_ulong_t arm_r1; 40 compat_ulong_t arm_r2; 41 compat_ulong_t arm_r3; 42 compat_ulong_t arm_r4; 43 compat_ulong_t arm_r5; 44 compat_ulong_t arm_r6; 45 compat_ulong_t arm_r7; 46 compat_ulong_t arm_r8; 47 compat_ulong_t arm_r9; 48 compat_ulong_t arm_r10; 49 compat_ulong_t arm_fp; 50 compat_ulong_t arm_ip; 51 compat_ulong_t arm_sp; 52 compat_ulong_t arm_lr; 53 compat_ulong_t arm_pc; 54 compat_ulong_t arm_cpsr; 55 compat_ulong_t fault_address; 56 }; 57 58 struct compat_ucontext { 59 compat_ulong_t uc_flags; 60 compat_uptr_t uc_link; 61 compat_stack_t uc_stack; 62 struct compat_sigcontext uc_mcontext; 63 compat_sigset_t uc_sigmask; 64 int __unused[32 - (sizeof (compat_sigset_t) / sizeof (int))]; 65 compat_ulong_t uc_regspace[128] __attribute__((__aligned__(8))); 66 }; 67 68 struct compat_vfp_sigframe { 69 compat_ulong_t magic; 70 compat_ulong_t size; 71 struct compat_user_vfp { 72 compat_u64 fpregs[32]; 73 compat_ulong_t fpscr; 74 } ufp; 75 struct compat_user_vfp_exc { 76 compat_ulong_t fpexc; 77 compat_ulong_t fpinst; 78 compat_ulong_t fpinst2; 79 } ufp_exc; 80 } __attribute__((__aligned__(8))); 81 82 #define VFP_MAGIC 0x56465001 83 #define VFP_STORAGE_SIZE sizeof(struct compat_vfp_sigframe) 84 85 #define FSR_WRITE_SHIFT (11) 86 87 struct compat_aux_sigframe { 88 struct compat_vfp_sigframe vfp; 89 90 /* Something that isn't a valid magic number for any coprocessor. */ 91 unsigned long end_magic; 92 } __attribute__((__aligned__(8))); 93 94 struct compat_sigframe { 95 struct compat_ucontext uc; 96 compat_ulong_t retcode[2]; 97 }; 98 99 struct compat_rt_sigframe { 100 struct compat_siginfo info; 101 struct compat_sigframe sig; 102 }; 103 104 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 105 106 static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set) 107 { 108 compat_sigset_t cset; 109 110 cset.sig[0] = set->sig[0] & 0xffffffffull; 111 cset.sig[1] = set->sig[0] >> 32; 112 113 return copy_to_user(uset, &cset, sizeof(*uset)); 114 } 115 116 static inline int get_sigset_t(sigset_t *set, 117 const compat_sigset_t __user *uset) 118 { 119 compat_sigset_t s32; 120 121 if (copy_from_user(&s32, uset, sizeof(*uset))) 122 return -EFAULT; 123 124 set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32); 125 return 0; 126 } 127 128 int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from) 129 { 130 int err; 131 132 if (!access_ok(VERIFY_WRITE, to, sizeof(*to))) 133 return -EFAULT; 134 135 /* If you change siginfo_t structure, please be sure 136 * this code is fixed accordingly. 137 * It should never copy any pad contained in the structure 138 * to avoid security leaks, but must copy the generic 139 * 3 ints plus the relevant union member. 140 * This routine must convert siginfo from 64bit to 32bit as well 141 * at the same time. 142 */ 143 err = __put_user(from->si_signo, &to->si_signo); 144 err |= __put_user(from->si_errno, &to->si_errno); 145 err |= __put_user((short)from->si_code, &to->si_code); 146 if (from->si_code < 0) 147 err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, 148 SI_PAD_SIZE); 149 else switch (from->si_code & __SI_MASK) { 150 case __SI_KILL: 151 err |= __put_user(from->si_pid, &to->si_pid); 152 err |= __put_user(from->si_uid, &to->si_uid); 153 break; 154 case __SI_TIMER: 155 err |= __put_user(from->si_tid, &to->si_tid); 156 err |= __put_user(from->si_overrun, &to->si_overrun); 157 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, 158 &to->si_ptr); 159 break; 160 case __SI_POLL: 161 err |= __put_user(from->si_band, &to->si_band); 162 err |= __put_user(from->si_fd, &to->si_fd); 163 break; 164 case __SI_FAULT: 165 err |= __put_user((compat_uptr_t)(unsigned long)from->si_addr, 166 &to->si_addr); 167 #ifdef BUS_MCEERR_AO 168 /* 169 * Other callers might not initialize the si_lsb field, 170 * so check explicitely for the right codes here. 171 */ 172 if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) 173 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); 174 #endif 175 break; 176 case __SI_CHLD: 177 err |= __put_user(from->si_pid, &to->si_pid); 178 err |= __put_user(from->si_uid, &to->si_uid); 179 err |= __put_user(from->si_status, &to->si_status); 180 err |= __put_user(from->si_utime, &to->si_utime); 181 err |= __put_user(from->si_stime, &to->si_stime); 182 break; 183 case __SI_RT: /* This is not generated by the kernel as of now. */ 184 case __SI_MESGQ: /* But this is */ 185 err |= __put_user(from->si_pid, &to->si_pid); 186 err |= __put_user(from->si_uid, &to->si_uid); 187 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr); 188 break; 189 default: /* this is just in case for now ... */ 190 err |= __put_user(from->si_pid, &to->si_pid); 191 err |= __put_user(from->si_uid, &to->si_uid); 192 break; 193 } 194 return err; 195 } 196 197 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from) 198 { 199 memset(to, 0, sizeof *to); 200 201 if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) || 202 copy_from_user(to->_sifields._pad, 203 from->_sifields._pad, SI_PAD_SIZE)) 204 return -EFAULT; 205 206 return 0; 207 } 208 209 /* 210 * VFP save/restore code. 211 */ 212 static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) 213 { 214 struct fpsimd_state *fpsimd = ¤t->thread.fpsimd_state; 215 compat_ulong_t magic = VFP_MAGIC; 216 compat_ulong_t size = VFP_STORAGE_SIZE; 217 compat_ulong_t fpscr, fpexc; 218 int err = 0; 219 220 /* 221 * Save the hardware registers to the fpsimd_state structure. 222 * Note that this also saves V16-31, which aren't visible 223 * in AArch32. 224 */ 225 fpsimd_preserve_current_state(); 226 227 /* Place structure header on the stack */ 228 __put_user_error(magic, &frame->magic, err); 229 __put_user_error(size, &frame->size, err); 230 231 /* 232 * Now copy the FP registers. Since the registers are packed, 233 * we can copy the prefix we want (V0-V15) as it is. 234 * FIXME: Won't work if big endian. 235 */ 236 err |= __copy_to_user(&frame->ufp.fpregs, fpsimd->vregs, 237 sizeof(frame->ufp.fpregs)); 238 239 /* Create an AArch32 fpscr from the fpsr and the fpcr. */ 240 fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) | 241 (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK); 242 __put_user_error(fpscr, &frame->ufp.fpscr, err); 243 244 /* 245 * The exception register aren't available so we fake up a 246 * basic FPEXC and zero everything else. 247 */ 248 fpexc = (1 << 30); 249 __put_user_error(fpexc, &frame->ufp_exc.fpexc, err); 250 __put_user_error(0, &frame->ufp_exc.fpinst, err); 251 __put_user_error(0, &frame->ufp_exc.fpinst2, err); 252 253 return err ? -EFAULT : 0; 254 } 255 256 static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) 257 { 258 struct fpsimd_state fpsimd; 259 compat_ulong_t magic = VFP_MAGIC; 260 compat_ulong_t size = VFP_STORAGE_SIZE; 261 compat_ulong_t fpscr; 262 int err = 0; 263 264 __get_user_error(magic, &frame->magic, err); 265 __get_user_error(size, &frame->size, err); 266 267 if (err) 268 return -EFAULT; 269 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) 270 return -EINVAL; 271 272 /* 273 * Copy the FP registers into the start of the fpsimd_state. 274 * FIXME: Won't work if big endian. 275 */ 276 err |= __copy_from_user(fpsimd.vregs, frame->ufp.fpregs, 277 sizeof(frame->ufp.fpregs)); 278 279 /* Extract the fpsr and the fpcr from the fpscr */ 280 __get_user_error(fpscr, &frame->ufp.fpscr, err); 281 fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK; 282 fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK; 283 284 /* 285 * We don't need to touch the exception register, so 286 * reload the hardware state. 287 */ 288 if (!err) 289 fpsimd_update_current_state(&fpsimd); 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 /* set the compat FSR WnR */ 504 __put_user_error(!!(current->thread.fault_code & ESR_EL1_WRITE) << 505 FSR_WRITE_SHIFT, &sf->uc.uc_mcontext.error_code, err); 506 __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err); 507 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 508 509 err |= put_sigset_t(&sf->uc.uc_sigmask, set); 510 511 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; 512 513 if (err == 0) 514 err |= compat_preserve_vfp_context(&aux->vfp); 515 __put_user_error(0, &aux->end_magic, err); 516 517 return err; 518 } 519 520 /* 521 * 32-bit signal handling routines called from signal.c 522 */ 523 int compat_setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, 524 sigset_t *set, struct pt_regs *regs) 525 { 526 struct compat_rt_sigframe __user *frame; 527 int err = 0; 528 529 frame = compat_get_sigframe(ka, regs, sizeof(*frame)); 530 531 if (!frame) 532 return 1; 533 534 err |= copy_siginfo_to_user32(&frame->info, info); 535 536 __put_user_error(0, &frame->sig.uc.uc_flags, err); 537 __put_user_error(0, &frame->sig.uc.uc_link, err); 538 539 err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp); 540 541 err |= compat_setup_sigframe(&frame->sig, regs, set); 542 543 if (err == 0) { 544 compat_setup_return(regs, ka, frame->sig.retcode, frame, usig); 545 regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info; 546 regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc; 547 } 548 549 return err; 550 } 551 552 int compat_setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, 553 struct pt_regs *regs) 554 { 555 struct compat_sigframe __user *frame; 556 int err = 0; 557 558 frame = compat_get_sigframe(ka, regs, sizeof(*frame)); 559 560 if (!frame) 561 return 1; 562 563 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 564 565 err |= compat_setup_sigframe(frame, regs, set); 566 if (err == 0) 567 compat_setup_return(regs, ka, frame->retcode, frame, usig); 568 569 return err; 570 } 571 572 void compat_setup_restart_syscall(struct pt_regs *regs) 573 { 574 regs->regs[7] = __NR_compat_restart_syscall; 575 } 576