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, const 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 ? -EFAULT : 0;
 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 ? -EFAULT : 0;
 152 }
 153
 154 static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs)
 155 {
 156         _sigregs32 user_sregs;
 157         int i;
 158
 159         user_sregs.regs.psw.mask = (__u32)(regs->psw.mask >> 32);
 160         user_sregs.regs.psw.mask &= PSW32_MASK_USER | PSW32_MASK_RI;
 161         user_sregs.regs.psw.mask |= PSW32_USER_BITS;
 162         user_sregs.regs.psw.addr = (__u32) regs->psw.addr |
 163                 (__u32)(regs->psw.mask & PSW_MASK_BA);
 164         for (i = 0; i < NUM_GPRS; i++)
 165                 user_sregs.regs.gprs[i] = (__u32) regs->gprs[i];
 166         save_access_regs(current->thread.acrs);
 167         memcpy(&user_sregs.regs.acrs, current->thread.acrs,
 168                sizeof(user_sregs.regs.acrs));
 169         save_fp_ctl(&current->thread.fp_regs.fpc);
 170         save_fp_regs(current->thread.fp_regs.fprs);
 171         memcpy(&user_sregs.fpregs, &current->thread.fp_regs,
 172                sizeof(user_sregs.fpregs));
 173         if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs32)))
 174                 return -EFAULT;
 175         return 0;
 176 }
 177
 178 static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
 179 {
 180         _sigregs32 user_sregs;
 181         int i;
 182
 183         /* Alwys make any pending restarted system call return -EINTR */
 184         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 185
 186         if (__copy_from_user(&user_sregs, &sregs->regs, sizeof(user_sregs)))
 187                 return -EFAULT;
 188
 189         if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW32_MASK_RI))
 190                 return -EINVAL;
 191
 192         /* Loading the floating-point-control word can fail. Do that first. */
 193         if (restore_fp_ctl(&user_sregs.fpregs.fpc))
 194                 return -EINVAL;
 195
 196         /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
 197         regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
 198                 (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_USER) << 32 |
 199                 (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_RI) << 32 |
 200                 (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_AMODE);
 201         /* Check for invalid user address space control. */
 202         if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
 203                 regs->psw.mask = PSW_ASC_PRIMARY |
 204                         (regs->psw.mask & ~PSW_MASK_ASC);
 205         regs->psw.addr = (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_INSN);
 206         for (i = 0; i < NUM_GPRS; i++)
 207                 regs->gprs[i] = (__u64) user_sregs.regs.gprs[i];
 208         memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
 209                sizeof(current->thread.acrs));
 210         restore_access_regs(current->thread.acrs);
 211
 212         memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
 213                sizeof(current->thread.fp_regs));
 214
 215         restore_fp_regs(current->thread.fp_regs.fprs);
 216         clear_thread_flag(TIF_SYSCALL); /* No longer in a system call */
 217         return 0;
 218 }
 219
 220 static int save_sigregs_gprs_high(struct pt_regs *regs, __u32 __user *uregs)
 221 {
 222         __u32 gprs_high[NUM_GPRS];
 223         int i;
 224
 225         for (i = 0; i < NUM_GPRS; i++)
 226                 gprs_high[i] = regs->gprs[i] >> 32;
 227         if (__copy_to_user(uregs, &gprs_high, sizeof(gprs_high)))
 228                 return -EFAULT;
 229         return 0;
 230 }
 231
 232 static int restore_sigregs_gprs_high(struct pt_regs *regs, __u32 __user *uregs)
 233 {
 234         __u32 gprs_high[NUM_GPRS];
 235         int i;
 236
 237         if (__copy_from_user(&gprs_high, uregs, sizeof(gprs_high)))
 238                 return -EFAULT;
 239         for (i = 0; i < NUM_GPRS; i++)
 240                 *(__u32 *)&regs->gprs[i] = gprs_high[i];
 241         return 0;
 242 }
 243
 244 asmlinkage long sys32_sigreturn(void)
 245 {
 246         struct pt_regs *regs = task_pt_regs(current);
 247         sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
 248         sigset_t set;
 249
 250         if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32))
 251                 goto badframe;
 252         set_current_blocked(&set);
 253         if (restore_sigregs32(regs, &frame->sregs))
 254                 goto badframe;
 255         if (restore_sigregs_gprs_high(regs, frame->gprs_high))
 256                 goto badframe;
 257         return regs->gprs[2];
 258 badframe:
 259         force_sig(SIGSEGV, current);
 260         return 0;
 261 }
 262
 263 asmlinkage long sys32_rt_sigreturn(void)
 264 {
 265         struct pt_regs *regs = task_pt_regs(current);
 266         rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
 267         sigset_t set;
 268
 269         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 270                 goto badframe;
 271         set_current_blocked(&set);
 272         if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
 273                 goto badframe;
 274         if (restore_sigregs_gprs_high(regs, frame->gprs_high))
 275                 goto badframe;
 276         if (compat_restore_altstack(&frame->uc.uc_stack))
 277                 goto badframe;
 278         return regs->gprs[2];
 279 badframe:
 280         force_sig(SIGSEGV, current);
 281         return 0;
 282 }
 283
 284 /*
 285  * Set up a signal frame.
 286  */
 287
 288
 289 /*
 290  * Determine which stack to use..
 291  */
 292 static inline void __user *
 293 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 294 {
 295         unsigned long sp;
 296
 297         /* Default to using normal stack */
 298         sp = (unsigned long) A(regs->gprs[15]);
 299
 300         /* Overflow on alternate signal stack gives SIGSEGV. */
 301         if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
 302                 return (void __user *) -1UL;
 303
 304         /* This is the X/Open sanctioned signal stack switching.  */
 305         if (ka->sa.sa_flags & SA_ONSTACK) {
 306                 if (! sas_ss_flags(sp))
 307                         sp = current->sas_ss_sp + current->sas_ss_size;
 308         }
 309
 310         return (void __user *)((sp - frame_size) & -8ul);
 311 }
 312
 313 static inline int map_signal(int sig)
 314 {
 315         if (current_thread_info()->exec_domain
 316             && current_thread_info()->exec_domain->signal_invmap
 317             && sig < 32)
 318                 return current_thread_info()->exec_domain->signal_invmap[sig];
 319         else
 320                 return sig;
 321 }
 322
 323 static int setup_frame32(int sig, struct k_sigaction *ka,
 324                         sigset_t *set, struct pt_regs * regs)
 325 {
 326         sigframe32 __user *frame = get_sigframe(ka, regs, sizeof(sigframe32));
 327
 328         if (frame == (void __user *) -1UL)
 329                 goto give_sigsegv;
 330
 331         if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE32))
 332                 goto give_sigsegv;
 333
 334         if (save_sigregs32(regs, &frame->sregs))
 335                 goto give_sigsegv;
 336         if (save_sigregs_gprs_high(regs, frame->gprs_high))
 337                 goto give_sigsegv;
 338         if (__put_user((unsigned long) &frame->sregs, &frame->sc.sregs))
 339                 goto give_sigsegv;
 340
 341         /* Set up to return from userspace.  If provided, use a stub
 342            already in userspace.  */
 343         if (ka->sa.sa_flags & SA_RESTORER) {
 344                 regs->gprs[14] = (__u64 __force) ka->sa.sa_restorer | PSW32_ADDR_AMODE;
 345         } else {
 346                 regs->gprs[14] = (__u64 __force) frame->retcode | PSW32_ADDR_AMODE;
 347                 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
 348                                (u16 __force __user *)(frame->retcode)))
 349                         goto give_sigsegv;
 350         }
 351
 352         /* Set up backchain. */
 353         if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
 354                 goto give_sigsegv;
 355
 356         /* Set up registers for signal handler */
 357         regs->gprs[15] = (__force __u64) frame;
 358         /* Force 31 bit amode and default user address space control. */
 359         regs->psw.mask = PSW_MASK_BA |
 360                 (PSW_USER_BITS & PSW_MASK_ASC) |
 361                 (regs->psw.mask & ~PSW_MASK_ASC);
 362         regs->psw.addr = (__force __u64) ka->sa.sa_handler;
 363
 364         regs->gprs[2] = map_signal(sig);
 365         regs->gprs[3] = (__force __u64) &frame->sc;
 366
 367         /* We forgot to include these in the sigcontext.
 368            To avoid breaking binary compatibility, they are passed as args. */
 369         if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
 370             sig == SIGTRAP || sig == SIGFPE) {
 371                 /* set extra registers only for synchronous signals */
 372                 regs->gprs[4] = regs->int_code & 127;
 373                 regs->gprs[5] = regs->int_parm_long;
 374                 regs->gprs[6] = task_thread_info(current)->last_break;
 375         }
 376
 377         /* Place signal number on stack to allow backtrace from handler.  */
 378         if (__put_user(regs->gprs[2], (int __force __user *) &frame->signo))
 379                 goto give_sigsegv;
 380         return 0;
 381
 382 give_sigsegv:
 383         force_sigsegv(sig, current);
 384         return -EFAULT;
 385 }
 386
 387 static int setup_rt_frame32(int sig, struct k_sigaction *ka, siginfo_t *info,
 388                            sigset_t *set, struct pt_regs * regs)
 389 {
 390         int err = 0;
 391         rt_sigframe32 __user *frame = get_sigframe(ka, regs, sizeof(rt_sigframe32));
 392
 393         if (frame == (void __user *) -1UL)
 394                 goto give_sigsegv;
 395
 396         if (copy_siginfo_to_user32(&frame->info, info))
 397                 goto give_sigsegv;
 398
 399         /* Create the ucontext.  */
 400         err |= __put_user(UC_EXTENDED, &frame->uc.uc_flags);
 401         err |= __put_user(0, &frame->uc.uc_link);
 402         err |= __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]);
 403         err |= save_sigregs32(regs, &frame->uc.uc_mcontext);
 404         err |= save_sigregs_gprs_high(regs, frame->gprs_high);
 405         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 406         if (err)
 407                 goto give_sigsegv;
 408
 409         /* Set up to return from userspace.  If provided, use a stub
 410            already in userspace.  */
 411         if (ka->sa.sa_flags & SA_RESTORER) {
 412                 regs->gprs[14] = (__u64 __force) ka->sa.sa_restorer | PSW32_ADDR_AMODE;
 413         } else {
 414                 regs->gprs[14] = (__u64 __force) frame->retcode | PSW32_ADDR_AMODE;
 415                 err |= __put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
 416                                   (u16 __force __user *)(frame->retcode));
 417         }
 418
 419         /* Set up backchain. */
 420         if (__put_user(regs->gprs[15], (unsigned int __force __user *) frame))
 421                 goto give_sigsegv;
 422
 423         /* Set up registers for signal handler */
 424         regs->gprs[15] = (__force __u64) frame;
 425         /* Force 31 bit amode and default user address space control. */
 426         regs->psw.mask = PSW_MASK_BA |
 427                 (PSW_USER_BITS & PSW_MASK_ASC) |
 428                 (regs->psw.mask & ~PSW_MASK_ASC);
 429         regs->psw.addr = (__u64 __force) ka->sa.sa_handler;
 430
 431         regs->gprs[2] = map_signal(sig);
 432         regs->gprs[3] = (__force __u64) &frame->info;
 433         regs->gprs[4] = (__force __u64) &frame->uc;
 434         regs->gprs[5] = task_thread_info(current)->last_break;
 435         return 0;
 436
 437 give_sigsegv:
 438         force_sigsegv(sig, current);
 439         return -EFAULT;
 440 }
 441
 442 /*
 443  * OK, we're invoking a handler
 444  */
 445
 446 void handle_signal32(unsigned long sig, struct k_sigaction *ka,
 447                     siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
 448 {
 449         int ret;
 450
 451         /* Set up the stack frame */
 452         if (ka->sa.sa_flags & SA_SIGINFO)
 453                 ret = setup_rt_frame32(sig, ka, info, oldset, regs);
 454         else
 455                 ret = setup_frame32(sig, ka, oldset, regs);
 456         if (ret)
 457                 return;
 458         signal_delivered(sig, info, ka, regs,
 459                                  test_thread_flag(TIF_SINGLE_STEP));
 460 }
 461