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 <linux/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 explicitly 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 * We have to be careful with endianness, since the fpsimd context-switch 217 * code operates on 128-bit (Q) register values whereas the compat ABI 218 * uses an array of 64-bit (D) registers. Consequently, we need to swap 219 * the two halves of each Q register when running on a big-endian CPU. 220 */ 221 union __fpsimd_vreg { 222 __uint128_t raw; 223 struct { 224 #ifdef __AARCH64EB__ 225 u64 hi; 226 u64 lo; 227 #else 228 u64 lo; 229 u64 hi; 230 #endif 231 }; 232 }; 233 234 static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) 235 { 236 struct fpsimd_state *fpsimd = ¤t->thread.fpsimd_state; 237 compat_ulong_t magic = VFP_MAGIC; 238 compat_ulong_t size = VFP_STORAGE_SIZE; 239 compat_ulong_t fpscr, fpexc; 240 int i, err = 0; 241 242 /* 243 * Save the hardware registers to the fpsimd_state structure. 244 * Note that this also saves V16-31, which aren't visible 245 * in AArch32. 246 */ 247 fpsimd_preserve_current_state(); 248 249 /* Place structure header on the stack */ 250 __put_user_error(magic, &frame->magic, err); 251 __put_user_error(size, &frame->size, err); 252 253 /* 254 * Now copy the FP registers. Since the registers are packed, 255 * we can copy the prefix we want (V0-V15) as it is. 256 */ 257 for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) { 258 union __fpsimd_vreg vreg = { 259 .raw = fpsimd->vregs[i >> 1], 260 }; 261 262 __put_user_error(vreg.lo, &frame->ufp.fpregs[i], err); 263 __put_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err); 264 } 265 266 /* Create an AArch32 fpscr from the fpsr and the fpcr. */ 267 fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) | 268 (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK); 269 __put_user_error(fpscr, &frame->ufp.fpscr, err); 270 271 /* 272 * The exception register aren't available so we fake up a 273 * basic FPEXC and zero everything else. 274 */ 275 fpexc = (1 << 30); 276 __put_user_error(fpexc, &frame->ufp_exc.fpexc, err); 277 __put_user_error(0, &frame->ufp_exc.fpinst, err); 278 __put_user_error(0, &frame->ufp_exc.fpinst2, err); 279 280 return err ? -EFAULT : 0; 281 } 282 283 static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) 284 { 285 struct fpsimd_state fpsimd; 286 compat_ulong_t magic = VFP_MAGIC; 287 compat_ulong_t size = VFP_STORAGE_SIZE; 288 compat_ulong_t fpscr; 289 int i, err = 0; 290 291 __get_user_error(magic, &frame->magic, err); 292 __get_user_error(size, &frame->size, err); 293 294 if (err) 295 return -EFAULT; 296 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) 297 return -EINVAL; 298 299 /* Copy the FP registers into the start of the fpsimd_state. */ 300 for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) { 301 union __fpsimd_vreg vreg; 302 303 __get_user_error(vreg.lo, &frame->ufp.fpregs[i], err); 304 __get_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err); 305 fpsimd.vregs[i >> 1] = vreg.raw; 306 } 307 308 /* Extract the fpsr and the fpcr from the fpscr */ 309 __get_user_error(fpscr, &frame->ufp.fpscr, err); 310 fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK; 311 fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK; 312 313 /* 314 * We don't need to touch the exception register, so 315 * reload the hardware state. 316 */ 317 if (!err) 318 fpsimd_update_current_state(&fpsimd); 319 320 return err ? -EFAULT : 0; 321 } 322 323 static int compat_restore_sigframe(struct pt_regs *regs, 324 struct compat_sigframe __user *sf) 325 { 326 int err; 327 sigset_t set; 328 struct compat_aux_sigframe __user *aux; 329 330 err = get_sigset_t(&set, &sf->uc.uc_sigmask); 331 if (err == 0) { 332 sigdelsetmask(&set, ~_BLOCKABLE); 333 set_current_blocked(&set); 334 } 335 336 __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); 337 __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); 338 __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); 339 __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); 340 __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); 341 __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); 342 __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); 343 __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); 344 __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); 345 __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); 346 __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); 347 __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); 348 __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); 349 __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); 350 __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); 351 __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); 352 __get_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err); 353 354 /* 355 * Avoid compat_sys_sigreturn() restarting. 356 */ 357 regs->syscallno = ~0UL; 358 359 err |= !valid_user_regs(®s->user_regs, current); 360 361 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; 362 if (err == 0) 363 err |= compat_restore_vfp_context(&aux->vfp); 364 365 return err; 366 } 367 368 asmlinkage int compat_sys_sigreturn(struct pt_regs *regs) 369 { 370 struct compat_sigframe __user *frame; 371 372 /* Always make any pending restarted system calls return -EINTR */ 373 current->restart_block.fn = do_no_restart_syscall; 374 375 /* 376 * Since we stacked the signal on a 64-bit boundary, 377 * then 'sp' should be word aligned here. If it's 378 * not, then the user is trying to mess with us. 379 */ 380 if (regs->compat_sp & 7) 381 goto badframe; 382 383 frame = (struct compat_sigframe __user *)regs->compat_sp; 384 385 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 386 goto badframe; 387 388 if (compat_restore_sigframe(regs, frame)) 389 goto badframe; 390 391 return regs->regs[0]; 392 393 badframe: 394 if (show_unhandled_signals) 395 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n", 396 current->comm, task_pid_nr(current), __func__, 397 regs->pc, regs->compat_sp); 398 force_sig(SIGSEGV, current); 399 return 0; 400 } 401 402 asmlinkage int compat_sys_rt_sigreturn(struct pt_regs *regs) 403 { 404 struct compat_rt_sigframe __user *frame; 405 406 /* Always make any pending restarted system calls return -EINTR */ 407 current->restart_block.fn = do_no_restart_syscall; 408 409 /* 410 * Since we stacked the signal on a 64-bit boundary, 411 * then 'sp' should be word aligned here. If it's 412 * not, then the user is trying to mess with us. 413 */ 414 if (regs->compat_sp & 7) 415 goto badframe; 416 417 frame = (struct compat_rt_sigframe __user *)regs->compat_sp; 418 419 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 420 goto badframe; 421 422 if (compat_restore_sigframe(regs, &frame->sig)) 423 goto badframe; 424 425 if (compat_restore_altstack(&frame->sig.uc.uc_stack)) 426 goto badframe; 427 428 return regs->regs[0]; 429 430 badframe: 431 if (show_unhandled_signals) 432 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n", 433 current->comm, task_pid_nr(current), __func__, 434 regs->pc, regs->compat_sp); 435 force_sig(SIGSEGV, current); 436 return 0; 437 } 438 439 static void __user *compat_get_sigframe(struct ksignal *ksig, 440 struct pt_regs *regs, 441 int framesize) 442 { 443 compat_ulong_t sp = sigsp(regs->compat_sp, ksig); 444 void __user *frame; 445 446 /* 447 * ATPCS B01 mandates 8-byte alignment 448 */ 449 frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7)); 450 451 /* 452 * Check that we can actually write to the signal frame. 453 */ 454 if (!access_ok(VERIFY_WRITE, frame, framesize)) 455 frame = NULL; 456 457 return frame; 458 } 459 460 static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, 461 compat_ulong_t __user *rc, void __user *frame, 462 int usig) 463 { 464 compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler); 465 compat_ulong_t retcode; 466 compat_ulong_t spsr = regs->pstate & ~(PSR_f | COMPAT_PSR_E_BIT); 467 int thumb; 468 469 /* Check if the handler is written for ARM or Thumb */ 470 thumb = handler & 1; 471 472 if (thumb) 473 spsr |= COMPAT_PSR_T_BIT; 474 else 475 spsr &= ~COMPAT_PSR_T_BIT; 476 477 /* The IT state must be cleared for both ARM and Thumb-2 */ 478 spsr &= ~COMPAT_PSR_IT_MASK; 479 480 /* Restore the original endianness */ 481 spsr |= COMPAT_PSR_ENDSTATE; 482 483 if (ka->sa.sa_flags & SA_RESTORER) { 484 retcode = ptr_to_compat(ka->sa.sa_restorer); 485 } else { 486 /* Set up sigreturn pointer */ 487 unsigned int idx = thumb << 1; 488 489 if (ka->sa.sa_flags & SA_SIGINFO) 490 idx += 3; 491 492 retcode = AARCH32_VECTORS_BASE + 493 AARCH32_KERN_SIGRET_CODE_OFFSET + 494 (idx << 2) + thumb; 495 } 496 497 regs->regs[0] = usig; 498 regs->compat_sp = ptr_to_compat(frame); 499 regs->compat_lr = retcode; 500 regs->pc = handler; 501 regs->pstate = spsr; 502 } 503 504 static int compat_setup_sigframe(struct compat_sigframe __user *sf, 505 struct pt_regs *regs, sigset_t *set) 506 { 507 struct compat_aux_sigframe __user *aux; 508 int err = 0; 509 510 __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); 511 __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); 512 __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); 513 __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); 514 __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); 515 __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); 516 __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); 517 __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); 518 __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); 519 __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); 520 __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); 521 __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); 522 __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); 523 __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); 524 __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); 525 __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); 526 __put_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err); 527 528 __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err); 529 /* set the compat FSR WnR */ 530 __put_user_error(!!(current->thread.fault_code & ESR_ELx_WNR) << 531 FSR_WRITE_SHIFT, &sf->uc.uc_mcontext.error_code, err); 532 __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err); 533 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 534 535 err |= put_sigset_t(&sf->uc.uc_sigmask, set); 536 537 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; 538 539 if (err == 0) 540 err |= compat_preserve_vfp_context(&aux->vfp); 541 __put_user_error(0, &aux->end_magic, err); 542 543 return err; 544 } 545 546 /* 547 * 32-bit signal handling routines called from signal.c 548 */ 549 int compat_setup_rt_frame(int usig, struct ksignal *ksig, 550 sigset_t *set, struct pt_regs *regs) 551 { 552 struct compat_rt_sigframe __user *frame; 553 int err = 0; 554 555 frame = compat_get_sigframe(ksig, regs, sizeof(*frame)); 556 557 if (!frame) 558 return 1; 559 560 err |= copy_siginfo_to_user32(&frame->info, &ksig->info); 561 562 __put_user_error(0, &frame->sig.uc.uc_flags, err); 563 __put_user_error(0, &frame->sig.uc.uc_link, err); 564 565 err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp); 566 567 err |= compat_setup_sigframe(&frame->sig, regs, set); 568 569 if (err == 0) { 570 compat_setup_return(regs, &ksig->ka, frame->sig.retcode, frame, usig); 571 regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info; 572 regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc; 573 } 574 575 return err; 576 } 577 578 int compat_setup_frame(int usig, struct ksignal *ksig, sigset_t *set, 579 struct pt_regs *regs) 580 { 581 struct compat_sigframe __user *frame; 582 int err = 0; 583 584 frame = compat_get_sigframe(ksig, regs, sizeof(*frame)); 585 586 if (!frame) 587 return 1; 588 589 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 590 591 err |= compat_setup_sigframe(frame, regs, set); 592 if (err == 0) 593 compat_setup_return(regs, &ksig->ka, frame->retcode, frame, usig); 594 595 return err; 596 } 597 598 void compat_setup_restart_syscall(struct pt_regs *regs) 599 { 600 regs->regs[7] = __NR_compat_restart_syscall; 601 } 602