1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright IBM Corp. 2000, 2006 4 * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com) 5 * Gerhard Tonn (ton@de.ibm.com) 6 * 7 * Copyright (C) 1991, 1992 Linus Torvalds 8 * 9 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson 10 */ 11 12 #include <linux/compat.h> 13 #include <linux/sched.h> 14 #include <linux/sched/task_stack.h> 15 #include <linux/mm.h> 16 #include <linux/smp.h> 17 #include <linux/kernel.h> 18 #include <linux/signal.h> 19 #include <linux/errno.h> 20 #include <linux/wait.h> 21 #include <linux/ptrace.h> 22 #include <linux/unistd.h> 23 #include <linux/stddef.h> 24 #include <linux/tty.h> 25 #include <linux/personality.h> 26 #include <linux/binfmts.h> 27 #include <asm/ucontext.h> 28 #include <linux/uaccess.h> 29 #include <asm/lowcore.h> 30 #include <asm/switch_to.h> 31 #include "compat_linux.h" 32 #include "compat_ptrace.h" 33 #include "entry.h" 34 35 typedef struct 36 { 37 __u8 callee_used_stack[__SIGNAL_FRAMESIZE32]; 38 struct sigcontext32 sc; 39 _sigregs32 sregs; 40 int signo; 41 _sigregs_ext32 sregs_ext; 42 __u16 svc_insn; /* Offset of svc_insn is NOT fixed! */ 43 } sigframe32; 44 45 typedef struct 46 { 47 __u8 callee_used_stack[__SIGNAL_FRAMESIZE32]; 48 __u16 svc_insn; 49 compat_siginfo_t info; 50 struct ucontext32 uc; 51 } rt_sigframe32; 52 53 static inline void sigset_to_sigset32(unsigned long *set64, 54 compat_sigset_word *set32) 55 { 56 set32[0] = (compat_sigset_word) set64[0]; 57 set32[1] = (compat_sigset_word)(set64[0] >> 32); 58 } 59 60 static inline void sigset32_to_sigset(compat_sigset_word *set32, 61 unsigned long *set64) 62 { 63 set64[0] = (unsigned long) set32[0] | ((unsigned long) set32[1] << 32); 64 } 65 66 int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from) 67 { 68 int err; 69 70 /* If you change siginfo_t structure, please be sure 71 this code is fixed accordingly. 72 It should never copy any pad contained in the structure 73 to avoid security leaks, but must copy the generic 74 3 ints plus the relevant union member. 75 This routine must convert siginfo from 64bit to 32bit as well 76 at the same time. */ 77 err = __put_user(from->si_signo, &to->si_signo); 78 err |= __put_user(from->si_errno, &to->si_errno); 79 err |= __put_user(from->si_code, &to->si_code); 80 if (from->si_code < 0) 81 err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE); 82 else { 83 switch (siginfo_layout(from->si_signo, from->si_code)) { 84 case SIL_RT: 85 err |= __put_user(from->si_int, &to->si_int); 86 /* fallthrough */ 87 case SIL_KILL: 88 err |= __put_user(from->si_pid, &to->si_pid); 89 err |= __put_user(from->si_uid, &to->si_uid); 90 break; 91 case SIL_CHLD: 92 err |= __put_user(from->si_pid, &to->si_pid); 93 err |= __put_user(from->si_uid, &to->si_uid); 94 err |= __put_user(from->si_utime, &to->si_utime); 95 err |= __put_user(from->si_stime, &to->si_stime); 96 err |= __put_user(from->si_status, &to->si_status); 97 break; 98 case SIL_FAULT: 99 err |= __put_user((unsigned long) from->si_addr, 100 &to->si_addr); 101 break; 102 case SIL_POLL: 103 err |= __put_user(from->si_band, &to->si_band); 104 err |= __put_user(from->si_fd, &to->si_fd); 105 break; 106 case SIL_TIMER: 107 err |= __put_user(from->si_tid, &to->si_tid); 108 err |= __put_user(from->si_overrun, &to->si_overrun); 109 err |= __put_user(from->si_int, &to->si_int); 110 break; 111 default: 112 break; 113 } 114 } 115 return err ? -EFAULT : 0; 116 } 117 118 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from) 119 { 120 int err; 121 u32 tmp; 122 123 err = __get_user(to->si_signo, &from->si_signo); 124 err |= __get_user(to->si_errno, &from->si_errno); 125 err |= __get_user(to->si_code, &from->si_code); 126 127 if (to->si_code < 0) 128 err |= __copy_from_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE); 129 else { 130 switch (siginfo_layout(to->si_signo, to->si_code)) { 131 case SIL_RT: 132 err |= __get_user(to->si_int, &from->si_int); 133 /* fallthrough */ 134 case SIL_KILL: 135 err |= __get_user(to->si_pid, &from->si_pid); 136 err |= __get_user(to->si_uid, &from->si_uid); 137 break; 138 case SIL_CHLD: 139 err |= __get_user(to->si_pid, &from->si_pid); 140 err |= __get_user(to->si_uid, &from->si_uid); 141 err |= __get_user(to->si_utime, &from->si_utime); 142 err |= __get_user(to->si_stime, &from->si_stime); 143 err |= __get_user(to->si_status, &from->si_status); 144 break; 145 case SIL_FAULT: 146 err |= __get_user(tmp, &from->si_addr); 147 to->si_addr = (void __force __user *) 148 (u64) (tmp & PSW32_ADDR_INSN); 149 break; 150 case SIL_POLL: 151 err |= __get_user(to->si_band, &from->si_band); 152 err |= __get_user(to->si_fd, &from->si_fd); 153 break; 154 case SIL_TIMER: 155 err |= __get_user(to->si_tid, &from->si_tid); 156 err |= __get_user(to->si_overrun, &from->si_overrun); 157 err |= __get_user(to->si_int, &from->si_int); 158 break; 159 default: 160 break; 161 } 162 } 163 return err ? -EFAULT : 0; 164 } 165 166 /* Store registers needed to create the signal frame */ 167 static void store_sigregs(void) 168 { 169 save_access_regs(current->thread.acrs); 170 save_fpu_regs(); 171 } 172 173 /* Load registers after signal return */ 174 static void load_sigregs(void) 175 { 176 restore_access_regs(current->thread.acrs); 177 } 178 179 static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs) 180 { 181 _sigregs32 user_sregs; 182 int i; 183 184 user_sregs.regs.psw.mask = (__u32)(regs->psw.mask >> 32); 185 user_sregs.regs.psw.mask &= PSW32_MASK_USER | PSW32_MASK_RI; 186 user_sregs.regs.psw.mask |= PSW32_USER_BITS; 187 user_sregs.regs.psw.addr = (__u32) regs->psw.addr | 188 (__u32)(regs->psw.mask & PSW_MASK_BA); 189 for (i = 0; i < NUM_GPRS; i++) 190 user_sregs.regs.gprs[i] = (__u32) regs->gprs[i]; 191 memcpy(&user_sregs.regs.acrs, current->thread.acrs, 192 sizeof(user_sregs.regs.acrs)); 193 fpregs_store((_s390_fp_regs *) &user_sregs.fpregs, ¤t->thread.fpu); 194 if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs32))) 195 return -EFAULT; 196 return 0; 197 } 198 199 static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs) 200 { 201 _sigregs32 user_sregs; 202 int i; 203 204 /* Alwys make any pending restarted system call return -EINTR */ 205 current->restart_block.fn = do_no_restart_syscall; 206 207 if (__copy_from_user(&user_sregs, &sregs->regs, sizeof(user_sregs))) 208 return -EFAULT; 209 210 if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW32_MASK_RI)) 211 return -EINVAL; 212 213 /* Test the floating-point-control word. */ 214 if (test_fp_ctl(user_sregs.fpregs.fpc)) 215 return -EINVAL; 216 217 /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */ 218 regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) | 219 (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_USER) << 32 | 220 (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_RI) << 32 | 221 (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_AMODE); 222 /* Check for invalid user address space control. */ 223 if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME) 224 regs->psw.mask = PSW_ASC_PRIMARY | 225 (regs->psw.mask & ~PSW_MASK_ASC); 226 regs->psw.addr = (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_INSN); 227 for (i = 0; i < NUM_GPRS; i++) 228 regs->gprs[i] = (__u64) user_sregs.regs.gprs[i]; 229 memcpy(¤t->thread.acrs, &user_sregs.regs.acrs, 230 sizeof(current->thread.acrs)); 231 fpregs_load((_s390_fp_regs *) &user_sregs.fpregs, ¤t->thread.fpu); 232 233 clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */ 234 return 0; 235 } 236 237 static int save_sigregs_ext32(struct pt_regs *regs, 238 _sigregs_ext32 __user *sregs_ext) 239 { 240 __u32 gprs_high[NUM_GPRS]; 241 __u64 vxrs[__NUM_VXRS_LOW]; 242 int i; 243 244 /* Save high gprs to signal stack */ 245 for (i = 0; i < NUM_GPRS; i++) 246 gprs_high[i] = regs->gprs[i] >> 32; 247 if (__copy_to_user(&sregs_ext->gprs_high, &gprs_high, 248 sizeof(sregs_ext->gprs_high))) 249 return -EFAULT; 250 251 /* Save vector registers to signal stack */ 252 if (MACHINE_HAS_VX) { 253 for (i = 0; i < __NUM_VXRS_LOW; i++) 254 vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1); 255 if (__copy_to_user(&sregs_ext->vxrs_low, vxrs, 256 sizeof(sregs_ext->vxrs_low)) || 257 __copy_to_user(&sregs_ext->vxrs_high, 258 current->thread.fpu.vxrs + __NUM_VXRS_LOW, 259 sizeof(sregs_ext->vxrs_high))) 260 return -EFAULT; 261 } 262 return 0; 263 } 264 265 static int restore_sigregs_ext32(struct pt_regs *regs, 266 _sigregs_ext32 __user *sregs_ext) 267 { 268 __u32 gprs_high[NUM_GPRS]; 269 __u64 vxrs[__NUM_VXRS_LOW]; 270 int i; 271 272 /* Restore high gprs from signal stack */ 273 if (__copy_from_user(&gprs_high, &sregs_ext->gprs_high, 274 sizeof(sregs_ext->gprs_high))) 275 return -EFAULT; 276 for (i = 0; i < NUM_GPRS; i++) 277 *(__u32 *)®s->gprs[i] = gprs_high[i]; 278 279 /* Restore vector registers from signal stack */ 280 if (MACHINE_HAS_VX) { 281 if (__copy_from_user(vxrs, &sregs_ext->vxrs_low, 282 sizeof(sregs_ext->vxrs_low)) || 283 __copy_from_user(current->thread.fpu.vxrs + __NUM_VXRS_LOW, 284 &sregs_ext->vxrs_high, 285 sizeof(sregs_ext->vxrs_high))) 286 return -EFAULT; 287 for (i = 0; i < __NUM_VXRS_LOW; i++) 288 *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = vxrs[i]; 289 } 290 return 0; 291 } 292 293 COMPAT_SYSCALL_DEFINE0(sigreturn) 294 { 295 struct pt_regs *regs = task_pt_regs(current); 296 sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15]; 297 compat_sigset_t cset; 298 sigset_t set; 299 300 if (__copy_from_user(&cset.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32)) 301 goto badframe; 302 sigset32_to_sigset(cset.sig, set.sig); 303 set_current_blocked(&set); 304 save_fpu_regs(); 305 if (restore_sigregs32(regs, &frame->sregs)) 306 goto badframe; 307 if (restore_sigregs_ext32(regs, &frame->sregs_ext)) 308 goto badframe; 309 load_sigregs(); 310 return regs->gprs[2]; 311 badframe: 312 force_sig(SIGSEGV, current); 313 return 0; 314 } 315 316 COMPAT_SYSCALL_DEFINE0(rt_sigreturn) 317 { 318 struct pt_regs *regs = task_pt_regs(current); 319 rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15]; 320 compat_sigset_t cset; 321 sigset_t set; 322 323 if (__copy_from_user(&cset, &frame->uc.uc_sigmask, sizeof(cset))) 324 goto badframe; 325 sigset32_to_sigset(cset.sig, set.sig); 326 set_current_blocked(&set); 327 if (compat_restore_altstack(&frame->uc.uc_stack)) 328 goto badframe; 329 save_fpu_regs(); 330 if (restore_sigregs32(regs, &frame->uc.uc_mcontext)) 331 goto badframe; 332 if (restore_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext)) 333 goto badframe; 334 load_sigregs(); 335 return regs->gprs[2]; 336 badframe: 337 force_sig(SIGSEGV, current); 338 return 0; 339 } 340 341 /* 342 * Set up a signal frame. 343 */ 344 345 346 /* 347 * Determine which stack to use.. 348 */ 349 static inline void __user * 350 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size) 351 { 352 unsigned long sp; 353 354 /* Default to using normal stack */ 355 sp = (unsigned long) A(regs->gprs[15]); 356 357 /* Overflow on alternate signal stack gives SIGSEGV. */ 358 if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL)) 359 return (void __user *) -1UL; 360 361 /* This is the X/Open sanctioned signal stack switching. */ 362 if (ka->sa.sa_flags & SA_ONSTACK) { 363 if (! sas_ss_flags(sp)) 364 sp = current->sas_ss_sp + current->sas_ss_size; 365 } 366 367 return (void __user *)((sp - frame_size) & -8ul); 368 } 369 370 static int setup_frame32(struct ksignal *ksig, sigset_t *set, 371 struct pt_regs *regs) 372 { 373 int sig = ksig->sig; 374 sigframe32 __user *frame; 375 struct sigcontext32 sc; 376 unsigned long restorer; 377 size_t frame_size; 378 379 /* 380 * gprs_high are always present for 31-bit compat tasks. 381 * The space for vector registers is only allocated if 382 * the machine supports it 383 */ 384 frame_size = sizeof(*frame) - sizeof(frame->sregs_ext.__reserved); 385 if (!MACHINE_HAS_VX) 386 frame_size -= sizeof(frame->sregs_ext.vxrs_low) + 387 sizeof(frame->sregs_ext.vxrs_high); 388 frame = get_sigframe(&ksig->ka, regs, frame_size); 389 if (frame == (void __user *) -1UL) 390 return -EFAULT; 391 392 /* Set up backchain. */ 393 if (__put_user(regs->gprs[15], (unsigned int __user *) frame)) 394 return -EFAULT; 395 396 /* Create struct sigcontext32 on the signal stack */ 397 sigset_to_sigset32(set->sig, sc.oldmask); 398 sc.sregs = (__u32)(unsigned long __force) &frame->sregs; 399 if (__copy_to_user(&frame->sc, &sc, sizeof(frame->sc))) 400 return -EFAULT; 401 402 /* Store registers needed to create the signal frame */ 403 store_sigregs(); 404 405 /* Create _sigregs32 on the signal stack */ 406 if (save_sigregs32(regs, &frame->sregs)) 407 return -EFAULT; 408 409 /* Place signal number on stack to allow backtrace from handler. */ 410 if (__put_user(regs->gprs[2], (int __force __user *) &frame->signo)) 411 return -EFAULT; 412 413 /* Create _sigregs_ext32 on the signal stack */ 414 if (save_sigregs_ext32(regs, &frame->sregs_ext)) 415 return -EFAULT; 416 417 /* Set up to return from userspace. If provided, use a stub 418 already in userspace. */ 419 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 420 restorer = (unsigned long __force) 421 ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE; 422 } else { 423 /* Signal frames without vectors registers are short ! */ 424 __u16 __user *svc = (void __user *) frame + frame_size - 2; 425 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc)) 426 return -EFAULT; 427 restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE; 428 } 429 430 /* Set up registers for signal handler */ 431 regs->gprs[14] = restorer; 432 regs->gprs[15] = (__force __u64) frame; 433 /* Force 31 bit amode and default user address space control. */ 434 regs->psw.mask = PSW_MASK_BA | 435 (PSW_USER_BITS & PSW_MASK_ASC) | 436 (regs->psw.mask & ~PSW_MASK_ASC); 437 regs->psw.addr = (__force __u64) ksig->ka.sa.sa_handler; 438 439 regs->gprs[2] = sig; 440 regs->gprs[3] = (__force __u64) &frame->sc; 441 442 /* We forgot to include these in the sigcontext. 443 To avoid breaking binary compatibility, they are passed as args. */ 444 if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL || 445 sig == SIGTRAP || sig == SIGFPE) { 446 /* set extra registers only for synchronous signals */ 447 regs->gprs[4] = regs->int_code & 127; 448 regs->gprs[5] = regs->int_parm_long; 449 regs->gprs[6] = current->thread.last_break; 450 } 451 452 return 0; 453 } 454 455 static int setup_rt_frame32(struct ksignal *ksig, sigset_t *set, 456 struct pt_regs *regs) 457 { 458 compat_sigset_t cset; 459 rt_sigframe32 __user *frame; 460 unsigned long restorer; 461 size_t frame_size; 462 u32 uc_flags; 463 464 frame_size = sizeof(*frame) - 465 sizeof(frame->uc.uc_mcontext_ext.__reserved); 466 /* 467 * gprs_high are always present for 31-bit compat tasks. 468 * The space for vector registers is only allocated if 469 * the machine supports it 470 */ 471 uc_flags = UC_GPRS_HIGH; 472 if (MACHINE_HAS_VX) { 473 uc_flags |= UC_VXRS; 474 } else 475 frame_size -= sizeof(frame->uc.uc_mcontext_ext.vxrs_low) + 476 sizeof(frame->uc.uc_mcontext_ext.vxrs_high); 477 frame = get_sigframe(&ksig->ka, regs, frame_size); 478 if (frame == (void __user *) -1UL) 479 return -EFAULT; 480 481 /* Set up backchain. */ 482 if (__put_user(regs->gprs[15], (unsigned int __force __user *) frame)) 483 return -EFAULT; 484 485 /* Set up to return from userspace. If provided, use a stub 486 already in userspace. */ 487 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 488 restorer = (unsigned long __force) 489 ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE; 490 } else { 491 __u16 __user *svc = &frame->svc_insn; 492 if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc)) 493 return -EFAULT; 494 restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE; 495 } 496 497 /* Create siginfo on the signal stack */ 498 if (copy_siginfo_to_user32(&frame->info, &ksig->info)) 499 return -EFAULT; 500 501 /* Store registers needed to create the signal frame */ 502 store_sigregs(); 503 504 /* Create ucontext on the signal stack. */ 505 sigset_to_sigset32(set->sig, cset.sig); 506 if (__put_user(uc_flags, &frame->uc.uc_flags) || 507 __put_user(0, &frame->uc.uc_link) || 508 __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]) || 509 save_sigregs32(regs, &frame->uc.uc_mcontext) || 510 __copy_to_user(&frame->uc.uc_sigmask, &cset, sizeof(cset)) || 511 save_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext)) 512 return -EFAULT; 513 514 /* Set up registers for signal handler */ 515 regs->gprs[14] = restorer; 516 regs->gprs[15] = (__force __u64) frame; 517 /* Force 31 bit amode and default user address space control. */ 518 regs->psw.mask = PSW_MASK_BA | 519 (PSW_USER_BITS & PSW_MASK_ASC) | 520 (regs->psw.mask & ~PSW_MASK_ASC); 521 regs->psw.addr = (__u64 __force) ksig->ka.sa.sa_handler; 522 523 regs->gprs[2] = ksig->sig; 524 regs->gprs[3] = (__force __u64) &frame->info; 525 regs->gprs[4] = (__force __u64) &frame->uc; 526 regs->gprs[5] = current->thread.last_break; 527 return 0; 528 } 529 530 /* 531 * OK, we're invoking a handler 532 */ 533 534 void handle_signal32(struct ksignal *ksig, sigset_t *oldset, 535 struct pt_regs *regs) 536 { 537 int ret; 538 539 /* Set up the stack frame */ 540 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 541 ret = setup_rt_frame32(ksig, oldset, regs); 542 else 543 ret = setup_frame32(ksig, oldset, regs); 544 545 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP)); 546 } 547 548