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         __u32 gprs_high[NUM_GPRS];
  40         __u8 retcode[S390_SYSCALL_SIZE];
  41 } sigframe32;
  42
  43 typedef struct
  44 {
  45         __u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
  46         __u8 retcode[S390_SYSCALL_SIZE];
  47         compat_siginfo_t info;
  48         struct ucontext32 uc;
  49         __u32 gprs_high[NUM_GPRS];
  50 } rt_sigframe32;
  51
  52 int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
  53 {
  54         int err;
  55
  56         /* If you change siginfo_t structure, please be sure
  57            this code is fixed accordingly.
  58            It should never copy any pad contained in the structure
  59            to avoid security leaks, but must copy the generic
  60            3 ints plus the relevant union member.
  61            This routine must convert siginfo from 64bit to 32bit as well
  62            at the same time.  */
  63         err = __put_user(from->si_signo, &to->si_signo);
  64         err |= __put_user(from->si_errno, &to->si_errno);
  65         err |= __put_user((short)from->si_code, &to->si_code);
  66         if (from->si_code < 0)
  67                 err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
  68         else {
  69                 switch (from->si_code >> 16) {
  70                 case __SI_RT >> 16: /* This is not generated by the kernel as of now.  */
  71                 case __SI_MESGQ >> 16:
  72                         err |= __put_user(from->si_int, &to->si_int);
  73                         /* fallthrough */
  74                 case __SI_KILL >> 16:
  75                         err |= __put_user(from->si_pid, &to->si_pid);
  76                         err |= __put_user(from->si_uid, &to->si_uid);
  77                         break;
  78                 case __SI_CHLD >> 16:
  79                         err |= __put_user(from->si_pid, &to->si_pid);
  80                         err |= __put_user(from->si_uid, &to->si_uid);
  81                         err |= __put_user(from->si_utime, &to->si_utime);
  82                         err |= __put_user(from->si_stime, &to->si_stime);
  83                         err |= __put_user(from->si_status, &to->si_status);
  84                         break;
  85                 case __SI_FAULT >> 16:
  86                         err |= __put_user((unsigned long) from->si_addr,
  87                                           &to->si_addr);
  88                         break;
  89                 case __SI_POLL >> 16:
  90                         err |= __put_user(from->si_band, &to->si_band);
  91                         err |= __put_user(from->si_fd, &to->si_fd);
  92                         break;
  93                 case __SI_TIMER >> 16:
  94                         err |= __put_user(from->si_tid, &to->si_tid);
  95                         err |= __put_user(from->si_overrun, &to->si_overrun);
  96                         err |= __put_user(from->si_int, &to->si_int);
  97                         break;
  98                 default:
  99                         break;
 100                 }
 101         }
 102         return err;
 103 }
 104
 105 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
 106 {
 107         int err;
 108         u32 tmp;
 109
 110         err = __get_user(to->si_signo, &from->si_signo);
 111         err |= __get_user(to->si_errno, &from->si_errno);
 112         err |= __get_user(to->si_code, &from->si_code);
 113
 114         if (to->si_code < 0)
 115                 err |= __copy_from_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
 116         else {
 117                 switch (to->si_code >> 16) {
 118                 case __SI_RT >> 16: /* This is not generated by the kernel as of now.  */
 119                 case __SI_MESGQ >> 16:
 120                         err |= __get_user(to->si_int, &from->si_int);
 121                         /* fallthrough */
 122                 case __SI_KILL >> 16:
 123                         err |= __get_user(to->si_pid, &from->si_pid);
 124                         err |= __get_user(to->si_uid, &from->si_uid);
 125                         break;
 126                 case __SI_CHLD >> 16:
 127                         err |= __get_user(to->si_pid, &from->si_pid);
 128                         err |= __get_user(to->si_uid, &from->si_uid);
 129                         err |= __get_user(to->si_utime, &from->si_utime);
 130                         err |= __get_user(to->si_stime, &from->si_stime);
 131                         err |= __get_user(to->si_status, &from->si_status);
 132                         break;
 133                 case __SI_FAULT >> 16:
 134                         err |= __get_user(tmp, &from->si_addr);
 135                         to->si_addr = (void __force __user *)
 136                                 (u64) (tmp & PSW32_ADDR_INSN);
 137                         break;
 138                 case __SI_POLL >> 16:
 139                         err |= __get_user(to->si_band, &from->si_band);
 140                         err |= __get_user(to->si_fd, &from->si_fd);
 141                         break;
 142                 case __SI_TIMER >> 16:
 143                         err |= __get_user(to->si_tid, &from->si_tid);
 144                         err |= __get_user(to->si_overrun, &from->si_overrun);
 145                         err |= __get_user(to->si_int, &from->si_int);
 146                         break;
 147                 default:
 148                         break;
 149                 }
 150         }
 151         return err;
 152 }
 153
 154 static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs)
 155 {
 156         _s390_regs_common32 regs32;
 157         int err, i;
 158
 159         regs32.psw.mask = psw32_user_bits |
 160                 ((__u32)(regs->psw.mask >> 32) & PSW32_MASK_USER);
 161         regs32.psw.addr = (__u32) regs->psw.addr |
 162                 (__u32)(regs->psw.mask & PSW_MASK_BA);
 163         for (i = 0; i < NUM_GPRS; i++)
 164                 regs32.gprs[i] = (__u32) regs->gprs[i];
 165         save_access_regs(current->thread.acrs);
 166         memcpy(regs32.acrs, current->thread.acrs, sizeof(regs32.acrs));
 167         err = __copy_to_user(&sregs->regs, &regs32, sizeof(regs32));
 168         if (err)
 169                 return err;
 170         save_fp_regs(&current->thread.fp_regs);
 171         /* s390_fp_regs and _s390_fp_regs32 are the same ! */
 172         return __copy_to_user(&sregs->fpregs, &current->thread.fp_regs,
 173                               sizeof(_s390_fp_regs32));
 174 }
 175
 176 static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
 177 {
 178         _s390_regs_common32 regs32;
 179         int err, i;
 180
 181         /* Alwys make any pending restarted system call return -EINTR */
 182         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 183
 184         err = __copy_from_user(&regs32, &sregs->regs, sizeof(regs32));
 185         if (err)
 186                 return err;
 187         regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
 188                 (__u64)(regs32.psw.mask & PSW32_MASK_USER) << 32 |
 189                 (__u64)(regs32.psw.addr & PSW32_ADDR_AMODE);
 190         /* Check for invalid user address space control. */
 191         if ((regs->psw.mask & PSW_MASK_ASC) >= (psw_kernel_bits & PSW_MASK_ASC))
 192                 regs->psw.mask = (psw_user_bits & PSW_MASK_ASC) |
 193                         (regs->psw.mask & ~PSW_MASK_ASC);
 194         regs->psw.addr = (__u64)(regs32.psw.addr & PSW32_ADDR_INSN);
 195         for (i = 0; i < NUM_GPRS; i++)
 196                 regs->gprs[i] = (__u64) regs32.gprs[i];
 197         memcpy(current->thread.acrs, regs32.acrs, sizeof(current->thread.acrs));
 198         restore_access_regs(current->thread.acrs);
 199
 200         err = __copy_from_user(&current->thread.fp_regs, &sregs->fpregs,
 201                                sizeof(_s390_fp_regs32));
 202         current->thread.fp_regs.fpc &= FPC_VALID_MASK;
 203         if (err)
 204                 return err;
 205
 206         restore_fp_regs(&current->thread.fp_regs);
 207         clear_thread_flag(TIF_SYSCALL); /* No longer in a system call */
 208         return 0;
 209 }
 210
 211 static int save_sigregs_gprs_high(struct pt_regs *regs, __u32 __user *uregs)
 212 {
 213         __u32 gprs_high[NUM_GPRS];
 214         int i;
 215
 216         for (i = 0; i < NUM_GPRS; i++)
 217                 gprs_high[i] = regs->gprs[i] >> 32;
 218
 219         return __copy_to_user(uregs, &gprs_high, sizeof(gprs_high));
 220 }
 221
 222 static int restore_sigregs_gprs_high(struct pt_regs *regs, __u32 __user *uregs)
 223 {
 224         __u32 gprs_high[NUM_GPRS];
 225         int err, i;
 226
 227         err = __copy_from_user(&gprs_high, uregs, sizeof(gprs_high));
 228         if (err)
 229                 return err;
 230         for (i = 0; i < NUM_GPRS; i++)
 231                 *(__u32 *)&regs->gprs[i] = gprs_high[i];
 232         return 0;
 233 }
 234
 235 asmlinkage long sys32_sigreturn(void)
 236 {
 237         struct pt_regs *regs = task_pt_regs(current);
 238         sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
 239         sigset_t set;
 240
 241         if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32))
 242                 goto badframe;
 243         set_current_blocked(&set);
 244         if (restore_sigregs32(regs, &frame->sregs))
 245                 goto badframe;
 246         if (restore_sigregs_gprs_high(regs, frame->gprs_high))
 247                 goto badframe;
 248         return regs->gprs[2];
 249 badframe:
 250         force_sig(SIGSEGV, current);
 251         return 0;
 252 }
 253
 254 asmlinkage long sys32_rt_sigreturn(void)
 255 {
 256         struct pt_regs *regs = task_pt_regs(current);
 257         rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
 258         sigset_t set;
 259
 260         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 261                 goto badframe;
 262         set_current_blocked(&set);
 263         if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
 264                 goto badframe;
 265         if (restore_sigregs_gprs_high(regs, frame->gprs_high))
 266                 goto badframe;
 267         if (compat_restore_altstack(&frame->uc.uc_stack))
 268                 goto badframe;
 269         return regs->gprs[2];
 270 badframe:
 271         force_sig(SIGSEGV, current);
 272         return 0;
 273 }
 274
 275 /*
 276  * Set up a signal frame.
 277  */
 278
 279
 280 /*
 281  * Determine which stack to use..
 282  */
 283 static inline void __user *
 284 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 285 {
 286         unsigned long sp;
 287
 288         /* Default to using normal stack */
 289         sp = (unsigned long) A(regs->gprs[15]);
 290
 291         /* Overflow on alternate signal stack gives SIGSEGV. */
 292         if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
 293                 return (void __user *) -1UL;
 294
 295         /* This is the X/Open sanctioned signal stack switching.  */
 296         if (ka->sa.sa_flags & SA_ONSTACK) {
 297                 if (! sas_ss_flags(sp))
 298                         sp = current->sas_ss_sp + current->sas_ss_size;
 299         }
 300
 301         return (void __user *)((sp - frame_size) & -8ul);
 302 }
 303
 304 static inline int map_signal(int sig)
 305 {
 306         if (current_thread_info()->exec_domain
 307             && current_thread_info()->exec_domain->signal_invmap
 308             && sig < 32)
 309                 return current_thread_info()->exec_domain->signal_invmap[sig];
 310         else
 311                 return sig;
 312 }
 313
 314 static int setup_frame32(int sig, struct k_sigaction *ka,
 315                         sigset_t *set, struct pt_regs * regs)
 316 {
 317         sigframe32 __user *frame = get_sigframe(ka, regs, sizeof(sigframe32));
 318
 319         if (frame == (void __user *) -1UL)
 320                 goto give_sigsegv;
 321
 322         if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE32))
 323                 goto give_sigsegv;
 324
 325         if (save_sigregs32(regs, &frame->sregs))
 326                 goto give_sigsegv;
 327         if (save_sigregs_gprs_high(regs, frame->gprs_high))
 328                 goto give_sigsegv;
 329         if (__put_user((unsigned long) &frame->sregs, &frame->sc.sregs))
 330                 goto give_sigsegv;
 331
 332         /* Set up to return from userspace.  If provided, use a stub
 333            already in userspace.  */
 334         if (ka->sa.sa_flags & SA_RESTORER) {
 335                 regs->gprs[14] = (__u64) ka->sa.sa_restorer | PSW32_ADDR_AMODE;
 336         } else {
 337                 regs->gprs[14] = (__u64) frame->retcode | PSW32_ADDR_AMODE;
 338                 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
 339                                (u16 __force __user *)(frame->retcode)))
 340                         goto give_sigsegv;
 341         }
 342
 343         /* Set up backchain. */
 344         if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
 345                 goto give_sigsegv;
 346
 347         /* Set up registers for signal handler */
 348         regs->gprs[15] = (__force __u64) frame;
 349         /* Force 31 bit amode and default user address space control. */
 350         regs->psw.mask = PSW_MASK_BA |
 351                 (psw_user_bits & PSW_MASK_ASC) |
 352                 (regs->psw.mask & ~PSW_MASK_ASC);
 353         regs->psw.addr = (__force __u64) ka->sa.sa_handler;
 354
 355         regs->gprs[2] = map_signal(sig);
 356         regs->gprs[3] = (__force __u64) &frame->sc;
 357
 358         /* We forgot to include these in the sigcontext.
 359            To avoid breaking binary compatibility, they are passed as args. */
 360         if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
 361             sig == SIGTRAP || sig == SIGFPE) {
 362                 /* set extra registers only for synchronous signals */
 363                 regs->gprs[4] = regs->int_code & 127;
 364                 regs->gprs[5] = regs->int_parm_long;
 365                 regs->gprs[6] = task_thread_info(current)->last_break;
 366         }
 367
 368         /* Place signal number on stack to allow backtrace from handler.  */
 369         if (__put_user(regs->gprs[2], (int __force __user *) &frame->signo))
 370                 goto give_sigsegv;
 371         return 0;
 372
 373 give_sigsegv:
 374         force_sigsegv(sig, current);
 375         return -EFAULT;
 376 }
 377
 378 static int setup_rt_frame32(int sig, struct k_sigaction *ka, siginfo_t *info,
 379                            sigset_t *set, struct pt_regs * regs)
 380 {
 381         int err = 0;
 382         rt_sigframe32 __user *frame = get_sigframe(ka, regs, sizeof(rt_sigframe32));
 383
 384         if (frame == (void __user *) -1UL)
 385                 goto give_sigsegv;
 386
 387         if (copy_siginfo_to_user32(&frame->info, info))
 388                 goto give_sigsegv;
 389
 390         /* Create the ucontext.  */
 391         err |= __put_user(UC_EXTENDED, &frame->uc.uc_flags);
 392         err |= __put_user(0, &frame->uc.uc_link);
 393         err |= __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]);
 394         err |= save_sigregs32(regs, &frame->uc.uc_mcontext);
 395         err |= save_sigregs_gprs_high(regs, frame->gprs_high);
 396         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 397         if (err)
 398                 goto give_sigsegv;
 399
 400         /* Set up to return from userspace.  If provided, use a stub
 401            already in userspace.  */
 402         if (ka->sa.sa_flags & SA_RESTORER) {
 403                 regs->gprs[14] = (__u64) ka->sa.sa_restorer | PSW32_ADDR_AMODE;
 404         } else {
 405                 regs->gprs[14] = (__u64) frame->retcode | PSW32_ADDR_AMODE;
 406                 err |= __put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
 407                                   (u16 __force __user *)(frame->retcode));
 408         }
 409
 410         /* Set up backchain. */
 411         if (__put_user(regs->gprs[15], (unsigned int __force __user *) frame))
 412                 goto give_sigsegv;
 413
 414         /* Set up registers for signal handler */
 415         regs->gprs[15] = (__force __u64) frame;
 416         /* Force 31 bit amode and default user address space control. */
 417         regs->psw.mask = PSW_MASK_BA |
 418                 (psw_user_bits & PSW_MASK_ASC) |
 419                 (regs->psw.mask & ~PSW_MASK_ASC);
 420         regs->psw.addr = (__u64) ka->sa.sa_handler;
 421
 422         regs->gprs[2] = map_signal(sig);
 423         regs->gprs[3] = (__force __u64) &frame->info;
 424         regs->gprs[4] = (__force __u64) &frame->uc;
 425         regs->gprs[5] = task_thread_info(current)->last_break;
 426         return 0;
 427
 428 give_sigsegv:
 429         force_sigsegv(sig, current);
 430         return -EFAULT;
 431 }
 432
 433 /*
 434  * OK, we're invoking a handler
 435  */
 436
 437 void handle_signal32(unsigned long sig, struct k_sigaction *ka,
 438                     siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
 439 {
 440         int ret;
 441
 442         /* Set up the stack frame */
 443         if (ka->sa.sa_flags & SA_SIGINFO)
 444                 ret = setup_rt_frame32(sig, ka, info, oldset, regs);
 445         else
 446                 ret = setup_frame32(sig, ka, oldset, regs);
 447         if (ret)
 448                 return;
 449         signal_delivered(sig, info, ka, regs,
 450                                  test_thread_flag(TIF_SINGLE_STEP));
 451 }
 452