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/unistd.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(from->si_int, &to->si_int); 158 break; 159 case __SI_POLL: 160 err |= __put_user(from->si_band, &to->si_band); 161 err |= __put_user(from->si_fd, &to->si_fd); 162 break; 163 case __SI_FAULT: 164 err |= __put_user((compat_uptr_t)(unsigned long)from->si_addr, 165 &to->si_addr); 166 #ifdef BUS_MCEERR_AO 167 /* 168 * Other callers might not initialize the si_lsb field, 169 * so check explicitely for the right codes here. 170 */ 171 if (from->si_signo == SIGBUS && 172 (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(from->si_int, &to->si_int); 188 break; 189 case __SI_SYS: 190 err |= __put_user((compat_uptr_t)(unsigned long) 191 from->si_call_addr, &to->si_call_addr); 192 err |= __put_user(from->si_syscall, &to->si_syscall); 193 err |= __put_user(from->si_arch, &to->si_arch); 194 break; 195 default: /* this is just in case for now ... */ 196 err |= __put_user(from->si_pid, &to->si_pid); 197 err |= __put_user(from->si_uid, &to->si_uid); 198 break; 199 } 200 return err; 201 } 202 203 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from) 204 { 205 if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) || 206 copy_from_user(to->_sifields._pad, 207 from->_sifields._pad, SI_PAD_SIZE)) 208 return -EFAULT; 209 210 return 0; 211 } 212 213 /* 214 * VFP save/restore code. 215 */ 216 static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) 217 { 218 struct fpsimd_state *fpsimd = ¤t->thread.fpsimd_state; 219 compat_ulong_t magic = VFP_MAGIC; 220 compat_ulong_t size = VFP_STORAGE_SIZE; 221 compat_ulong_t fpscr, fpexc; 222 int err = 0; 223 224 /* 225 * Save the hardware registers to the fpsimd_state structure. 226 * Note that this also saves V16-31, which aren't visible 227 * in AArch32. 228 */ 229 fpsimd_preserve_current_state(); 230 231 /* Place structure header on the stack */ 232 __put_user_error(magic, &frame->magic, err); 233 __put_user_error(size, &frame->size, err); 234 235 /* 236 * Now copy the FP registers. Since the registers are packed, 237 * we can copy the prefix we want (V0-V15) as it is. 238 * FIXME: Won't work if big endian. 239 */ 240 err |= __copy_to_user(&frame->ufp.fpregs, fpsimd->vregs, 241 sizeof(frame->ufp.fpregs)); 242 243 /* Create an AArch32 fpscr from the fpsr and the fpcr. */ 244 fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) | 245 (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK); 246 __put_user_error(fpscr, &frame->ufp.fpscr, err); 247 248 /* 249 * The exception register aren't available so we fake up a 250 * basic FPEXC and zero everything else. 251 */ 252 fpexc = (1 << 30); 253 __put_user_error(fpexc, &frame->ufp_exc.fpexc, err); 254 __put_user_error(0, &frame->ufp_exc.fpinst, err); 255 __put_user_error(0, &frame->ufp_exc.fpinst2, err); 256 257 return err ? -EFAULT : 0; 258 } 259 260 static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) 261 { 262 struct fpsimd_state fpsimd; 263 compat_ulong_t magic = VFP_MAGIC; 264 compat_ulong_t size = VFP_STORAGE_SIZE; 265 compat_ulong_t fpscr; 266 int err = 0; 267 268 __get_user_error(magic, &frame->magic, err); 269 __get_user_error(size, &frame->size, err); 270 271 if (err) 272 return -EFAULT; 273 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) 274 return -EINVAL; 275 276 /* 277 * Copy the FP registers into the start of the fpsimd_state. 278 * FIXME: Won't work if big endian. 279 */ 280 err |= __copy_from_user(fpsimd.vregs, frame->ufp.fpregs, 281 sizeof(frame->ufp.fpregs)); 282 283 /* Extract the fpsr and the fpcr from the fpscr */ 284 __get_user_error(fpscr, &frame->ufp.fpscr, err); 285 fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK; 286 fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK; 287 288 /* 289 * We don't need to touch the exception register, so 290 * reload the hardware state. 291 */ 292 if (!err) 293 fpsimd_update_current_state(&fpsimd); 294 295 return err ? -EFAULT : 0; 296 } 297 298 static int compat_restore_sigframe(struct pt_regs *regs, 299 struct compat_sigframe __user *sf) 300 { 301 int err; 302 sigset_t set; 303 struct compat_aux_sigframe __user *aux; 304 305 err = get_sigset_t(&set, &sf->uc.uc_sigmask); 306 if (err == 0) { 307 sigdelsetmask(&set, ~_BLOCKABLE); 308 set_current_blocked(&set); 309 } 310 311 __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); 312 __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); 313 __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); 314 __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); 315 __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); 316 __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); 317 __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); 318 __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); 319 __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); 320 __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); 321 __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); 322 __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); 323 __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); 324 __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); 325 __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); 326 __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); 327 __get_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err); 328 329 /* 330 * Avoid compat_sys_sigreturn() restarting. 331 */ 332 regs->syscallno = ~0UL; 333 334 err |= !valid_user_regs(®s->user_regs); 335 336 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; 337 if (err == 0) 338 err |= compat_restore_vfp_context(&aux->vfp); 339 340 return err; 341 } 342 343 asmlinkage int compat_sys_sigreturn(struct pt_regs *regs) 344 { 345 struct compat_sigframe __user *frame; 346 347 /* Always make any pending restarted system calls return -EINTR */ 348 current->restart_block.fn = do_no_restart_syscall; 349 350 /* 351 * Since we stacked the signal on a 64-bit boundary, 352 * then 'sp' should be word aligned here. If it's 353 * not, then the user is trying to mess with us. 354 */ 355 if (regs->compat_sp & 7) 356 goto badframe; 357 358 frame = (struct compat_sigframe __user *)regs->compat_sp; 359 360 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 361 goto badframe; 362 363 if (compat_restore_sigframe(regs, frame)) 364 goto badframe; 365 366 return regs->regs[0]; 367 368 badframe: 369 if (show_unhandled_signals) 370 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n", 371 current->comm, task_pid_nr(current), __func__, 372 regs->pc, regs->compat_sp); 373 force_sig(SIGSEGV, current); 374 return 0; 375 } 376 377 asmlinkage int compat_sys_rt_sigreturn(struct pt_regs *regs) 378 { 379 struct compat_rt_sigframe __user *frame; 380 381 /* Always make any pending restarted system calls return -EINTR */ 382 current->restart_block.fn = do_no_restart_syscall; 383 384 /* 385 * Since we stacked the signal on a 64-bit boundary, 386 * then 'sp' should be word aligned here. If it's 387 * not, then the user is trying to mess with us. 388 */ 389 if (regs->compat_sp & 7) 390 goto badframe; 391 392 frame = (struct compat_rt_sigframe __user *)regs->compat_sp; 393 394 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 395 goto badframe; 396 397 if (compat_restore_sigframe(regs, &frame->sig)) 398 goto badframe; 399 400 if (compat_restore_altstack(&frame->sig.uc.uc_stack)) 401 goto badframe; 402 403 return regs->regs[0]; 404 405 badframe: 406 if (show_unhandled_signals) 407 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n", 408 current->comm, task_pid_nr(current), __func__, 409 regs->pc, regs->compat_sp); 410 force_sig(SIGSEGV, current); 411 return 0; 412 } 413 414 static void __user *compat_get_sigframe(struct ksignal *ksig, 415 struct pt_regs *regs, 416 int framesize) 417 { 418 compat_ulong_t sp = sigsp(regs->compat_sp, ksig); 419 void __user *frame; 420 421 /* 422 * ATPCS B01 mandates 8-byte alignment 423 */ 424 frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7)); 425 426 /* 427 * Check that we can actually write to the signal frame. 428 */ 429 if (!access_ok(VERIFY_WRITE, frame, framesize)) 430 frame = NULL; 431 432 return frame; 433 } 434 435 static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, 436 compat_ulong_t __user *rc, void __user *frame, 437 int usig) 438 { 439 compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler); 440 compat_ulong_t retcode; 441 compat_ulong_t spsr = regs->pstate & ~(PSR_f | COMPAT_PSR_E_BIT); 442 int thumb; 443 444 /* Check if the handler is written for ARM or Thumb */ 445 thumb = handler & 1; 446 447 if (thumb) 448 spsr |= COMPAT_PSR_T_BIT; 449 else 450 spsr &= ~COMPAT_PSR_T_BIT; 451 452 /* The IT state must be cleared for both ARM and Thumb-2 */ 453 spsr &= ~COMPAT_PSR_IT_MASK; 454 455 /* Restore the original endianness */ 456 spsr |= COMPAT_PSR_ENDSTATE; 457 458 if (ka->sa.sa_flags & SA_RESTORER) { 459 retcode = ptr_to_compat(ka->sa.sa_restorer); 460 } else { 461 /* Set up sigreturn pointer */ 462 unsigned int idx = thumb << 1; 463 464 if (ka->sa.sa_flags & SA_SIGINFO) 465 idx += 3; 466 467 retcode = AARCH32_VECTORS_BASE + 468 AARCH32_KERN_SIGRET_CODE_OFFSET + 469 (idx << 2) + thumb; 470 } 471 472 regs->regs[0] = usig; 473 regs->compat_sp = ptr_to_compat(frame); 474 regs->compat_lr = retcode; 475 regs->pc = handler; 476 regs->pstate = spsr; 477 } 478 479 static int compat_setup_sigframe(struct compat_sigframe __user *sf, 480 struct pt_regs *regs, sigset_t *set) 481 { 482 struct compat_aux_sigframe __user *aux; 483 int err = 0; 484 485 __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); 486 __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); 487 __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); 488 __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); 489 __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); 490 __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); 491 __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); 492 __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); 493 __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); 494 __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); 495 __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); 496 __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); 497 __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); 498 __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); 499 __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); 500 __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); 501 __put_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err); 502 503 __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err); 504 /* set the compat FSR WnR */ 505 __put_user_error(!!(current->thread.fault_code & ESR_ELx_WNR) << 506 FSR_WRITE_SHIFT, &sf->uc.uc_mcontext.error_code, err); 507 __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err); 508 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 509 510 err |= put_sigset_t(&sf->uc.uc_sigmask, set); 511 512 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; 513 514 if (err == 0) 515 err |= compat_preserve_vfp_context(&aux->vfp); 516 __put_user_error(0, &aux->end_magic, err); 517 518 return err; 519 } 520 521 /* 522 * 32-bit signal handling routines called from signal.c 523 */ 524 int compat_setup_rt_frame(int usig, struct ksignal *ksig, 525 sigset_t *set, struct pt_regs *regs) 526 { 527 struct compat_rt_sigframe __user *frame; 528 int err = 0; 529 530 frame = compat_get_sigframe(ksig, regs, sizeof(*frame)); 531 532 if (!frame) 533 return 1; 534 535 err |= copy_siginfo_to_user32(&frame->info, &ksig->info); 536 537 __put_user_error(0, &frame->sig.uc.uc_flags, err); 538 __put_user_error(0, &frame->sig.uc.uc_link, err); 539 540 err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp); 541 542 err |= compat_setup_sigframe(&frame->sig, regs, set); 543 544 if (err == 0) { 545 compat_setup_return(regs, &ksig->ka, frame->sig.retcode, frame, usig); 546 regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info; 547 regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc; 548 } 549 550 return err; 551 } 552 553 int compat_setup_frame(int usig, struct ksignal *ksig, sigset_t *set, 554 struct pt_regs *regs) 555 { 556 struct compat_sigframe __user *frame; 557 int err = 0; 558 559 frame = compat_get_sigframe(ksig, regs, sizeof(*frame)); 560 561 if (!frame) 562 return 1; 563 564 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 565 566 err |= compat_setup_sigframe(frame, regs, set); 567 if (err == 0) 568 compat_setup_return(regs, &ksig->ka, frame->retcode, frame, usig); 569 570 return err; 571 } 572 573 void compat_setup_restart_syscall(struct pt_regs *regs) 574 { 575 regs->regs[7] = __NR_compat_restart_syscall; 576 } 577