arch/s390/kernel/compat_signal.c

   1 /*
   2  *    Copyright IBM Corp. 2000, 2006
   3  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
   4  *               Gerhard Tonn (ton@de.ibm.com)
   5  *
   6  *  Copyright (C) 1991, 1992  Linus Torvalds
   7  *
   8  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   9  */
  10
  11 #include <linux/compat.h>
  12 #include <linux/sched.h>
  13 #include <linux/mm.h>
  14 #include <linux/smp.h>
  15 #include <linux/kernel.h>
  16 #include <linux/signal.h>
  17 #include <linux/errno.h>
  18 #include <linux/wait.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/unistd.h>
  21 #include <linux/stddef.h>
  22 #include <linux/tty.h>
  23 #include <linux/personality.h>
  24 #include <linux/binfmts.h>
  25 #include <asm/ucontext.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/lowcore.h>
  28 #include <asm/switch_to.h>
  29 #include "compat_linux.h"
  30 #include "compat_ptrace.h"
  31 #include "entry.h"
  32
  33 typedef struct
  34 {
  35         __u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
  36         struct sigcontext32 sc;
  37         _sigregs32 sregs;
  38         int signo;
  39         _sigregs_ext32 sregs_ext;
  40         __u16 svc_insn;         /* Offset of svc_insn is NOT fixed! */
  41 } sigframe32;
  42
  43 typedef struct
  44 {
  45         __u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
  46         __u16 svc_insn;
  47         compat_siginfo_t info;
  48         struct ucontext32 uc;
  49 } rt_sigframe32;
  50
  51 int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
  52 {
  53         int err;
  54
  55         /* If you change siginfo_t structure, please be sure
  56            this code is fixed accordingly.
  57            It should never copy any pad contained in the structure
  58            to avoid security leaks, but must copy the generic
  59            3 ints plus the relevant union member.
  60            This routine must convert siginfo from 64bit to 32bit as well
  61            at the same time.  */
  62         err = __put_user(from->si_signo, &to->si_signo);
  63         err |= __put_user(from->si_errno, &to->si_errno);
  64         err |= __put_user((short)from->si_code, &to->si_code);
  65         if (from->si_code < 0)
  66                 err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
  67         else {
  68                 switch (from->si_code >> 16) {
  69                 case __SI_RT >> 16: /* This is not generated by the kernel as of now.  */
  70                 case __SI_MESGQ >> 16:
  71                         err |= __put_user(from->si_int, &to->si_int);
  72                         /* fallthrough */
  73                 case __SI_KILL >> 16:
  74                         err |= __put_user(from->si_pid, &to->si_pid);
  75                         err |= __put_user(from->si_uid, &to->si_uid);
  76                         break;
  77                 case __SI_CHLD >> 16:
  78                         err |= __put_user(from->si_pid, &to->si_pid);
  79                         err |= __put_user(from->si_uid, &to->si_uid);
  80                         err |= __put_user(from->si_utime, &to->si_utime);
  81                         err |= __put_user(from->si_stime, &to->si_stime);
  82                         err |= __put_user(from->si_status, &to->si_status);
  83                         break;
  84                 case __SI_FAULT >> 16:
  85                         err |= __put_user((unsigned long) from->si_addr,
  86                                           &to->si_addr);
  87                         break;
  88                 case __SI_POLL >> 16:
  89                         err |= __put_user(from->si_band, &to->si_band);
  90                         err |= __put_user(from->si_fd, &to->si_fd);
  91                         break;
  92                 case __SI_TIMER >> 16:
  93                         err |= __put_user(from->si_tid, &to->si_tid);
  94                         err |= __put_user(from->si_overrun, &to->si_overrun);
  95                         err |= __put_user(from->si_int, &to->si_int);
  96                         break;
  97                 default:
  98                         break;
  99                 }
 100         }
 101         return err ? -EFAULT : 0;
 102 }
 103
 104 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
 105 {
 106         int err;
 107         u32 tmp;
 108
 109         err = __get_user(to->si_signo, &from->si_signo);
 110         err |= __get_user(to->si_errno, &from->si_errno);
 111         err |= __get_user(to->si_code, &from->si_code);
 112
 113         if (to->si_code < 0)
 114                 err |= __copy_from_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
 115         else {
 116                 switch (to->si_code >> 16) {
 117                 case __SI_RT >> 16: /* This is not generated by the kernel as of now.  */
 118                 case __SI_MESGQ >> 16:
 119                         err |= __get_user(to->si_int, &from->si_int);
 120                         /* fallthrough */
 121                 case __SI_KILL >> 16:
 122                         err |= __get_user(to->si_pid, &from->si_pid);
 123                         err |= __get_user(to->si_uid, &from->si_uid);
 124                         break;
 125                 case __SI_CHLD >> 16:
 126                         err |= __get_user(to->si_pid, &from->si_pid);
 127                         err |= __get_user(to->si_uid, &from->si_uid);
 128                         err |= __get_user(to->si_utime, &from->si_utime);
 129                         err |= __get_user(to->si_stime, &from->si_stime);
 130                         err |= __get_user(to->si_status, &from->si_status);
 131                         break;
 132                 case __SI_FAULT >> 16:
 133                         err |= __get_user(tmp, &from->si_addr);
 134                         to->si_addr = (void __force __user *)
 135                                 (u64) (tmp & PSW32_ADDR_INSN);
 136                         break;
 137                 case __SI_POLL >> 16:
 138                         err |= __get_user(to->si_band, &from->si_band);
 139                         err |= __get_user(to->si_fd, &from->si_fd);
 140                         break;
 141                 case __SI_TIMER >> 16:
 142                         err |= __get_user(to->si_tid, &from->si_tid);
 143                         err |= __get_user(to->si_overrun, &from->si_overrun);
 144                         err |= __get_user(to->si_int, &from->si_int);
 145                         break;
 146                 default:
 147                         break;
 148                 }
 149         }
 150         return err ? -EFAULT : 0;
 151 }
 152
 153 /* Store registers needed to create the signal frame */
 154 static void store_sigregs(void)
 155 {
 156         int i;
 157
 158         save_access_regs(current->thread.acrs);
 159         save_fp_ctl(&current->thread.fp_regs.fpc);
 160         if (current->thread.vxrs) {
 161                 save_vx_regs(current->thread.vxrs);
 162                 for (i = 0; i < __NUM_FPRS; i++)
 163                         current->thread.fp_regs.fprs[i] =
 164                                 *(freg_t *)(current->thread.vxrs + i);
 165         } else
 166                 save_fp_regs(current->thread.fp_regs.fprs);
 167 }
 168
 169 /* Load registers after signal return */
 170 static void load_sigregs(void)
 171 {
 172         int i;
 173
 174         restore_access_regs(current->thread.acrs);
 175         /* restore_fp_ctl is done in restore_sigregs */
 176         if (current->thread.vxrs) {
 177                 for (i = 0; i < __NUM_FPRS; i++)
 178                         *(freg_t *)(current->thread.vxrs + i) =
 179                                 current->thread.fp_regs.fprs[i];
 180                 restore_vx_regs(current->thread.vxrs);
 181         } else
 182                 restore_fp_regs(current->thread.fp_regs.fprs);
 183 }
 184
 185 static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs)
 186 {
 187         _sigregs32 user_sregs;
 188         int i;
 189
 190         user_sregs.regs.psw.mask = (__u32)(regs->psw.mask >> 32);
 191         user_sregs.regs.psw.mask &= PSW32_MASK_USER | PSW32_MASK_RI;
 192         user_sregs.regs.psw.mask |= PSW32_USER_BITS;
 193         user_sregs.regs.psw.addr = (__u32) regs->psw.addr |
 194                 (__u32)(regs->psw.mask & PSW_MASK_BA);
 195         for (i = 0; i < NUM_GPRS; i++)
 196                 user_sregs.regs.gprs[i] = (__u32) regs->gprs[i];
 197         memcpy(&user_sregs.regs.acrs, current->thread.acrs,
 198                sizeof(user_sregs.regs.acrs));
 199         memcpy(&user_sregs.fpregs, &current->thread.fp_regs,
 200                sizeof(user_sregs.fpregs));
 201         if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs32)))
 202                 return -EFAULT;
 203         return 0;
 204 }
 205
 206 static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
 207 {
 208         _sigregs32 user_sregs;
 209         int i;
 210
 211         /* Alwys make any pending restarted system call return -EINTR */
 212         current->restart_block.fn = do_no_restart_syscall;
 213
 214         if (__copy_from_user(&user_sregs, &sregs->regs, sizeof(user_sregs)))
 215                 return -EFAULT;
 216
 217         if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW32_MASK_RI))
 218                 return -EINVAL;
 219
 220         /* Loading the floating-point-control word can fail. Do that first. */
 221         if (restore_fp_ctl(&user_sregs.fpregs.fpc))
 222                 return -EINVAL;
 223
 224         /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
 225         regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
 226                 (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_USER) << 32 |
 227                 (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_RI) << 32 |
 228                 (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_AMODE);
 229         /* Check for invalid user address space control. */
 230         if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
 231                 regs->psw.mask = PSW_ASC_PRIMARY |
 232                         (regs->psw.mask & ~PSW_MASK_ASC);
 233         regs->psw.addr = (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_INSN);
 234         for (i = 0; i < NUM_GPRS; i++)
 235                 regs->gprs[i] = (__u64) user_sregs.regs.gprs[i];
 236         memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
 237                sizeof(current->thread.acrs));
 238
 239         memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
 240                sizeof(current->thread.fp_regs));
 241
 242         clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
 243         return 0;
 244 }
 245
 246 static int save_sigregs_ext32(struct pt_regs *regs,
 247                               _sigregs_ext32 __user *sregs_ext)
 248 {
 249         __u32 gprs_high[NUM_GPRS];
 250         __u64 vxrs[__NUM_VXRS_LOW];
 251         int i;
 252
 253         /* Save high gprs to signal stack */
 254         for (i = 0; i < NUM_GPRS; i++)
 255                 gprs_high[i] = regs->gprs[i] >> 32;
 256         if (__copy_to_user(&sregs_ext->gprs_high, &gprs_high,
 257                            sizeof(sregs_ext->gprs_high)))
 258                 return -EFAULT;
 259
 260         /* Save vector registers to signal stack */
 261         if (current->thread.vxrs) {
 262                 for (i = 0; i < __NUM_VXRS_LOW; i++)
 263                         vxrs[i] = *((__u64 *)(current->thread.vxrs + i) + 1);
 264                 if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
 265                                    sizeof(sregs_ext->vxrs_low)) ||
 266                     __copy_to_user(&sregs_ext->vxrs_high,
 267                                    current->thread.vxrs + __NUM_VXRS_LOW,
 268                                    sizeof(sregs_ext->vxrs_high)))
 269                         return -EFAULT;
 270         }
 271         return 0;
 272 }
 273
 274 static int restore_sigregs_ext32(struct pt_regs *regs,
 275                                  _sigregs_ext32 __user *sregs_ext)
 276 {
 277         __u32 gprs_high[NUM_GPRS];
 278         __u64 vxrs[__NUM_VXRS_LOW];
 279         int i;
 280
 281         /* Restore high gprs from signal stack */
 282         if (__copy_from_user(&gprs_high, &sregs_ext->gprs_high,
 283                              sizeof(&sregs_ext->gprs_high)))
 284                 return -EFAULT;
 285         for (i = 0; i < NUM_GPRS; i++)
 286                 *(__u32 *)&regs->gprs[i] = gprs_high[i];
 287
 288         /* Restore vector registers from signal stack */
 289         if (current->thread.vxrs) {
 290                 if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
 291                                      sizeof(sregs_ext->vxrs_low)) ||
 292                     __copy_from_user(current->thread.vxrs + __NUM_VXRS_LOW,
 293                                      &sregs_ext->vxrs_high,
 294                                      sizeof(sregs_ext->vxrs_high)))
 295                         return -EFAULT;
 296                 for (i = 0; i < __NUM_VXRS_LOW; i++)
 297                         *((__u64 *)(current->thread.vxrs + i) + 1) = vxrs[i];
 298         }
 299         return 0;
 300 }
 301
 302 COMPAT_SYSCALL_DEFINE0(sigreturn)
 303 {
 304         struct pt_regs *regs = task_pt_regs(current);
 305         sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
 306         sigset_t set;
 307
 308         if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32))
 309                 goto badframe;
 310         set_current_blocked(&set);
 311         if (restore_sigregs32(regs, &frame->sregs))
 312                 goto badframe;
 313         if (restore_sigregs_ext32(regs, &frame->sregs_ext))
 314                 goto badframe;
 315         load_sigregs();
 316         return regs->gprs[2];
 317 badframe:
 318         force_sig(SIGSEGV, current);
 319         return 0;
 320 }
 321
 322 COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
 323 {
 324         struct pt_regs *regs = task_pt_regs(current);
 325         rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
 326         sigset_t set;
 327
 328         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 329                 goto badframe;
 330         set_current_blocked(&set);
 331         if (compat_restore_altstack(&frame->uc.uc_stack))
 332                 goto badframe;
 333         if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
 334                 goto badframe;
 335         if (restore_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
 336                 goto badframe;
 337         load_sigregs();
 338         return regs->gprs[2];
 339 badframe:
 340         force_sig(SIGSEGV, current);
 341         return 0;
 342 }
 343
 344 /*
 345  * Set up a signal frame.
 346  */
 347
 348
 349 /*
 350  * Determine which stack to use..
 351  */
 352 static inline void __user *
 353 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 354 {
 355         unsigned long sp;
 356
 357         /* Default to using normal stack */
 358         sp = (unsigned long) A(regs->gprs[15]);
 359
 360         /* Overflow on alternate signal stack gives SIGSEGV. */
 361         if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
 362                 return (void __user *) -1UL;
 363
 364         /* This is the X/Open sanctioned signal stack switching.  */
 365         if (ka->sa.sa_flags & SA_ONSTACK) {
 366                 if (! sas_ss_flags(sp))
 367                         sp = current->sas_ss_sp + current->sas_ss_size;
 368         }
 369
 370         return (void __user *)((sp - frame_size) & -8ul);
 371 }
 372
 373 static int setup_frame32(struct ksignal *ksig, sigset_t *set,
 374                          struct pt_regs *regs)
 375 {
 376         int sig = ksig->sig;
 377         sigframe32 __user *frame;
 378         struct sigcontext32 sc;
 379         unsigned long restorer;
 380         size_t frame_size;
 381
 382         /*
 383          * gprs_high are always present for 31-bit compat tasks.
 384          * The space for vector registers is only allocated if
 385          * the machine supports it
 386          */
 387         frame_size = sizeof(*frame) - sizeof(frame->sregs_ext.__reserved);
 388         if (!MACHINE_HAS_VX)
 389                 frame_size -= sizeof(frame->sregs_ext.vxrs_low) +
 390                               sizeof(frame->sregs_ext.vxrs_high);
 391         frame = get_sigframe(&ksig->ka, regs, frame_size);
 392         if (frame == (void __user *) -1UL)
 393                 return -EFAULT;
 394
 395         /* Set up backchain. */
 396         if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
 397                 return -EFAULT;
 398
 399         /* Create struct sigcontext32 on the signal stack */
 400         memcpy(&sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE32);
 401         sc.sregs = (__u32)(unsigned long __force) &frame->sregs;
 402         if (__copy_to_user(&frame->sc, &sc, sizeof(frame->sc)))
 403                 return -EFAULT;
 404
 405         /* Store registers needed to create the signal frame */
 406         store_sigregs();
 407
 408         /* Create _sigregs32 on the signal stack */
 409         if (save_sigregs32(regs, &frame->sregs))
 410                 return -EFAULT;
 411
 412         /* Place signal number on stack to allow backtrace from handler.  */
 413         if (__put_user(regs->gprs[2], (int __force __user *) &frame->signo))
 414                 return -EFAULT;
 415
 416         /* Create _sigregs_ext32 on the signal stack */
 417         if (save_sigregs_ext32(regs, &frame->sregs_ext))
 418                 return -EFAULT;
 419
 420         /* Set up to return from userspace.  If provided, use a stub
 421            already in userspace.  */
 422         if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 423                 restorer = (unsigned long __force)
 424                         ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
 425         } else {
 426                 /* Signal frames without vectors registers are short ! */
 427                 __u16 __user *svc = (void __user *) frame + frame_size - 2;
 428                 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
 429                         return -EFAULT;
 430                 restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
 431         }
 432
 433         /* Set up registers for signal handler */
 434         regs->gprs[14] = restorer;
 435         regs->gprs[15] = (__force __u64) frame;
 436         /* Force 31 bit amode and default user address space control. */
 437         regs->psw.mask = PSW_MASK_BA |
 438                 (PSW_USER_BITS & PSW_MASK_ASC) |
 439                 (regs->psw.mask & ~PSW_MASK_ASC);
 440         regs->psw.addr = (__force __u64) ksig->ka.sa.sa_handler;
 441
 442         regs->gprs[2] = sig;
 443         regs->gprs[3] = (__force __u64) &frame->sc;
 444
 445         /* We forgot to include these in the sigcontext.
 446            To avoid breaking binary compatibility, they are passed as args. */
 447         if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
 448             sig == SIGTRAP || sig == SIGFPE) {
 449                 /* set extra registers only for synchronous signals */
 450                 regs->gprs[4] = regs->int_code & 127;
 451                 regs->gprs[5] = regs->int_parm_long;
 452                 regs->gprs[6] = task_thread_info(current)->last_break;
 453         }
 454
 455         return 0;
 456 }
 457
 458 static int setup_rt_frame32(struct ksignal *ksig, sigset_t *set,
 459                             struct pt_regs *regs)
 460 {
 461         rt_sigframe32 __user *frame;
 462         unsigned long restorer;
 463         size_t frame_size;
 464         u32 uc_flags;
 465
 466         frame_size = sizeof(*frame) -
 467                      sizeof(frame->uc.uc_mcontext_ext.__reserved);
 468         /*
 469          * gprs_high are always present for 31-bit compat tasks.
 470          * The space for vector registers is only allocated if
 471          * the machine supports it
 472          */
 473         uc_flags = UC_GPRS_HIGH;
 474         if (MACHINE_HAS_VX) {
 475                 if (current->thread.vxrs)
 476                         uc_flags |= UC_VXRS;
 477         } else
 478                 frame_size -= sizeof(frame->uc.uc_mcontext_ext.vxrs_low) +
 479                               sizeof(frame->uc.uc_mcontext_ext.vxrs_high);
 480         frame = get_sigframe(&ksig->ka, regs, frame_size);
 481         if (frame == (void __user *) -1UL)
 482                 return -EFAULT;
 483
 484         /* Set up backchain. */
 485         if (__put_user(regs->gprs[15], (unsigned int __force __user *) frame))
 486                 return -EFAULT;
 487
 488         /* Set up to return from userspace.  If provided, use a stub
 489            already in userspace.  */
 490         if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 491                 restorer = (unsigned long __force)
 492                         ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
 493         } else {
 494                 __u16 __user *svc = &frame->svc_insn;
 495                 if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc))
 496                         return -EFAULT;
 497                 restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
 498         }
 499
 500         /* Create siginfo on the signal stack */
 501         if (copy_siginfo_to_user32(&frame->info, &ksig->info))
 502                 return -EFAULT;
 503
 504         /* Store registers needed to create the signal frame */
 505         store_sigregs();
 506
 507         /* Create ucontext on the signal stack. */
 508         if (__put_user(uc_flags, &frame->uc.uc_flags) ||
 509             __put_user(0, &frame->uc.uc_link) ||
 510             __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
 511             save_sigregs32(regs, &frame->uc.uc_mcontext) ||
 512             __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)) ||
 513             save_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
 514                 return -EFAULT;
 515
 516         /* Set up registers for signal handler */
 517         regs->gprs[14] = restorer;
 518         regs->gprs[15] = (__force __u64) frame;
 519         /* Force 31 bit amode and default user address space control. */
 520         regs->psw.mask = PSW_MASK_BA |
 521                 (PSW_USER_BITS & PSW_MASK_ASC) |
 522                 (regs->psw.mask & ~PSW_MASK_ASC);
 523         regs->psw.addr = (__u64 __force) ksig->ka.sa.sa_handler;
 524
 525         regs->gprs[2] = ksig->sig;
 526         regs->gprs[3] = (__force __u64) &frame->info;
 527         regs->gprs[4] = (__force __u64) &frame->uc;
 528         regs->gprs[5] = task_thread_info(current)->last_break;
 529         return 0;
 530 }
 531
 532 /*
 533  * OK, we're invoking a handler
 534  */
 535
 536 void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 537                      struct pt_regs *regs)
 538 {
 539         int ret;
 540
 541         /* Set up the stack frame */
 542         if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 543                 ret = setup_rt_frame32(ksig, oldset, regs);
 544         else
 545                 ret = setup_frame32(ksig, oldset, regs);
 546
 547         signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
 548 }
 549