arch/tile/kernel/compat_signal.c

   1 /*
   2  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  */
  14
  15 #include <linux/sched.h>
  16 #include <linux/mm.h>
  17 #include <linux/smp.h>
  18 #include <linux/kernel.h>
  19 #include <linux/signal.h>
  20 #include <linux/errno.h>
  21 #include <linux/wait.h>
  22 #include <linux/unistd.h>
  23 #include <linux/stddef.h>
  24 #include <linux/personality.h>
  25 #include <linux/suspend.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/elf.h>
  28 #include <linux/compat.h>
  29 #include <linux/syscalls.h>
  30 #include <linux/uaccess.h>
  31 #include <asm/processor.h>
  32 #include <asm/ucontext.h>
  33 #include <asm/sigframe.h>
  34 #include <asm/syscalls.h>
  35 #include <arch/interrupts.h>
  36
  37 struct compat_sigaction {
  38         compat_uptr_t sa_handler;
  39         compat_ulong_t sa_flags;
  40         compat_uptr_t sa_restorer;
  41         sigset_t sa_mask __packed;
  42 };
  43
  44 struct compat_sigaltstack {
  45         compat_uptr_t ss_sp;
  46         int ss_flags;
  47         compat_size_t ss_size;
  48 };
  49
  50 struct compat_ucontext {
  51         compat_ulong_t    uc_flags;
  52         compat_uptr_t     uc_link;
  53         struct compat_sigaltstack         uc_stack;
  54         struct sigcontext uc_mcontext;
  55         sigset_t          uc_sigmask;   /* mask last for extensibility */
  56 };
  57
  58 #define COMPAT_SI_PAD_SIZE      ((SI_MAX_SIZE - 3 * sizeof(int)) / sizeof(int))
  59
  60 struct compat_siginfo {
  61         int si_signo;
  62         int si_errno;
  63         int si_code;
  64
  65         union {
  66                 int _pad[COMPAT_SI_PAD_SIZE];
  67
  68                 /* kill() */
  69                 struct {
  70                         unsigned int _pid;      /* sender's pid */
  71                         unsigned int _uid;      /* sender's uid */
  72                 } _kill;
  73
  74                 /* POSIX.1b timers */
  75                 struct {
  76                         compat_timer_t _tid;    /* timer id */
  77                         int _overrun;           /* overrun count */
  78                         compat_sigval_t _sigval;        /* same as below */
  79                         int _sys_private;       /* not to be passed to user */
  80                         int _overrun_incr;      /* amount to add to overrun */
  81                 } _timer;
  82
  83                 /* POSIX.1b signals */
  84                 struct {
  85                         unsigned int _pid;      /* sender's pid */
  86                         unsigned int _uid;      /* sender's uid */
  87                         compat_sigval_t _sigval;
  88                 } _rt;
  89
  90                 /* SIGCHLD */
  91                 struct {
  92                         unsigned int _pid;      /* which child */
  93                         unsigned int _uid;      /* sender's uid */
  94                         int _status;            /* exit code */
  95                         compat_clock_t _utime;
  96                         compat_clock_t _stime;
  97                 } _sigchld;
  98
  99                 /* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
 100                 struct {
 101                         unsigned int _addr;     /* faulting insn/memory ref. */
 102 #ifdef __ARCH_SI_TRAPNO
 103                         int _trapno;    /* TRAP # which caused the signal */
 104 #endif
 105                 } _sigfault;
 106
 107                 /* SIGPOLL */
 108                 struct {
 109                         int _band;      /* POLL_IN, POLL_OUT, POLL_MSG */
 110                         int _fd;
 111                 } _sigpoll;
 112         } _sifields;
 113 };
 114
 115 struct compat_rt_sigframe {
 116         unsigned char save_area[C_ABI_SAVE_AREA_SIZE]; /* caller save area */
 117         struct compat_siginfo info;
 118         struct compat_ucontext uc;
 119 };
 120
 121 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 122
 123 long compat_sys_rt_sigaction(int sig, struct compat_sigaction __user *act,
 124                              struct compat_sigaction __user *oact,
 125                              size_t sigsetsize)
 126 {
 127         struct k_sigaction new_sa, old_sa;
 128         int ret = -EINVAL;
 129
 130         /* XXX: Don't preclude handling different sized sigset_t's.  */
 131         if (sigsetsize != sizeof(sigset_t))
 132                 goto out;
 133
 134         if (act) {
 135                 compat_uptr_t handler, restorer;
 136
 137                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
 138                     __get_user(handler, &act->sa_handler) ||
 139                     __get_user(new_sa.sa.sa_flags, &act->sa_flags) ||
 140                     __get_user(restorer, &act->sa_restorer) ||
 141                     __copy_from_user(&new_sa.sa.sa_mask, &act->sa_mask,
 142                                      sizeof(sigset_t)))
 143                         return -EFAULT;
 144                 new_sa.sa.sa_handler = compat_ptr(handler);
 145                 new_sa.sa.sa_restorer = compat_ptr(restorer);
 146         }
 147
 148         ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
 149
 150         if (!ret && oact) {
 151                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 152                     __put_user(ptr_to_compat(old_sa.sa.sa_handler),
 153                                &oact->sa_handler) ||
 154                     __put_user(ptr_to_compat(old_sa.sa.sa_restorer),
 155                                &oact->sa_restorer) ||
 156                     __put_user(old_sa.sa.sa_flags, &oact->sa_flags) ||
 157                     __copy_to_user(&oact->sa_mask, &old_sa.sa.sa_mask,
 158                                    sizeof(sigset_t)))
 159                         return -EFAULT;
 160         }
 161 out:
 162         return ret;
 163 }
 164
 165 long compat_sys_rt_sigqueueinfo(int pid, int sig,
 166                                 struct compat_siginfo __user *uinfo)
 167 {
 168         siginfo_t info;
 169         int ret;
 170         mm_segment_t old_fs = get_fs();
 171
 172         if (copy_siginfo_from_user32(&info, uinfo))
 173                 return -EFAULT;
 174         set_fs(KERNEL_DS);
 175         ret = sys_rt_sigqueueinfo(pid, sig, (siginfo_t __force __user *)&info);
 176         set_fs(old_fs);
 177         return ret;
 178 }
 179
 180 int copy_siginfo_to_user32(struct compat_siginfo __user *to, siginfo_t *from)
 181 {
 182         int err;
 183
 184         if (!access_ok(VERIFY_WRITE, to, sizeof(struct compat_siginfo)))
 185                 return -EFAULT;
 186
 187         /* If you change siginfo_t structure, please make sure that
 188            this code is fixed accordingly.
 189            It should never copy any pad contained in the structure
 190            to avoid security leaks, but must copy the generic
 191            3 ints plus the relevant union member.  */
 192         err = __put_user(from->si_signo, &to->si_signo);
 193         err |= __put_user(from->si_errno, &to->si_errno);
 194         err |= __put_user((short)from->si_code, &to->si_code);
 195
 196         if (from->si_code < 0) {
 197                 err |= __put_user(from->si_pid, &to->si_pid);
 198                 err |= __put_user(from->si_uid, &to->si_uid);
 199                 err |= __put_user(ptr_to_compat(from->si_ptr), &to->si_ptr);
 200         } else {
 201                 /*
 202                  * First 32bits of unions are always present:
 203                  * si_pid === si_band === si_tid === si_addr(LS half)
 204                  */
 205                 err |= __put_user(from->_sifields._pad[0],
 206                                   &to->_sifields._pad[0]);
 207                 switch (from->si_code >> 16) {
 208                 case __SI_FAULT >> 16:
 209                         break;
 210                 case __SI_CHLD >> 16:
 211                         err |= __put_user(from->si_utime, &to->si_utime);
 212                         err |= __put_user(from->si_stime, &to->si_stime);
 213                         err |= __put_user(from->si_status, &to->si_status);
 214                         /* FALL THROUGH */
 215                 default:
 216                 case __SI_KILL >> 16:
 217                         err |= __put_user(from->si_uid, &to->si_uid);
 218                         break;
 219                 case __SI_POLL >> 16:
 220                         err |= __put_user(from->si_fd, &to->si_fd);
 221                         break;
 222                 case __SI_TIMER >> 16:
 223                         err |= __put_user(from->si_overrun, &to->si_overrun);
 224                         err |= __put_user(ptr_to_compat(from->si_ptr),
 225                                           &to->si_ptr);
 226                         break;
 227                          /* This is not generated by the kernel as of now.  */
 228                 case __SI_RT >> 16:
 229                 case __SI_MESGQ >> 16:
 230                         err |= __put_user(from->si_uid, &to->si_uid);
 231                         err |= __put_user(from->si_int, &to->si_int);
 232                         break;
 233                 }
 234         }
 235         return err;
 236 }
 237
 238 int copy_siginfo_from_user32(siginfo_t *to, struct compat_siginfo __user *from)
 239 {
 240         int err;
 241         u32 ptr32;
 242
 243         if (!access_ok(VERIFY_READ, from, sizeof(struct compat_siginfo)))
 244                 return -EFAULT;
 245
 246         err = __get_user(to->si_signo, &from->si_signo);
 247         err |= __get_user(to->si_errno, &from->si_errno);
 248         err |= __get_user(to->si_code, &from->si_code);
 249
 250         err |= __get_user(to->si_pid, &from->si_pid);
 251         err |= __get_user(to->si_uid, &from->si_uid);
 252         err |= __get_user(ptr32, &from->si_ptr);
 253         to->si_ptr = compat_ptr(ptr32);
 254
 255         return err;
 256 }
 257
 258 long compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
 259                             struct compat_sigaltstack __user *uoss_ptr,
 260                             struct pt_regs *regs)
 261 {
 262         stack_t uss, uoss;
 263         int ret;
 264         mm_segment_t seg;
 265
 266         if (uss_ptr) {
 267                 u32 ptr;
 268
 269                 memset(&uss, 0, sizeof(stack_t));
 270                 if (!access_ok(VERIFY_READ, uss_ptr, sizeof(*uss_ptr)) ||
 271                             __get_user(ptr, &uss_ptr->ss_sp) ||
 272                             __get_user(uss.ss_flags, &uss_ptr->ss_flags) ||
 273                             __get_user(uss.ss_size, &uss_ptr->ss_size))
 274                         return -EFAULT;
 275                 uss.ss_sp = compat_ptr(ptr);
 276         }
 277         seg = get_fs();
 278         set_fs(KERNEL_DS);
 279         ret = do_sigaltstack(uss_ptr ? (stack_t __user __force *)&uss : NULL,
 280                              (stack_t __user __force *)&uoss,
 281                              (unsigned long)compat_ptr(regs->sp));
 282         set_fs(seg);
 283         if (ret >= 0 && uoss_ptr)  {
 284                 if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(*uoss_ptr)) ||
 285                     __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
 286                     __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
 287                     __put_user(uoss.ss_size, &uoss_ptr->ss_size))
 288                         ret = -EFAULT;
 289         }
 290         return ret;
 291 }
 292
 293 /* The assembly shim for this function arranges to ignore the return value. */
 294 long compat_sys_rt_sigreturn(struct pt_regs *regs)
 295 {
 296         struct compat_rt_sigframe __user *frame =
 297                 (struct compat_rt_sigframe __user *) compat_ptr(regs->sp);
 298         sigset_t set;
 299
 300         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 301                 goto badframe;
 302         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 303                 goto badframe;
 304
 305         sigdelsetmask(&set, ~_BLOCKABLE);
 306         set_current_blocked(&set);
 307
 308         if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 309                 goto badframe;
 310
 311         if (compat_sys_sigaltstack(&frame->uc.uc_stack, NULL, regs) != 0)
 312                 goto badframe;
 313
 314         return 0;
 315
 316 badframe:
 317         signal_fault("bad sigreturn frame", regs, frame, 0);
 318         return 0;
 319 }
 320
 321 /*
 322  * Determine which stack to use..
 323  */
 324 static inline void __user *compat_get_sigframe(struct k_sigaction *ka,
 325                                                struct pt_regs *regs,
 326                                                size_t frame_size)
 327 {
 328         unsigned long sp;
 329
 330         /* Default to using normal stack */
 331         sp = (unsigned long)compat_ptr(regs->sp);
 332
 333         /*
 334          * If we are on the alternate signal stack and would overflow
 335          * it, don't.  Return an always-bogus address instead so we
 336          * will die with SIGSEGV.
 337          */
 338         if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
 339                 return (void __user __force *)-1UL;
 340
 341         /* This is the X/Open sanctioned signal stack switching.  */
 342         if (ka->sa.sa_flags & SA_ONSTACK) {
 343                 if (sas_ss_flags(sp) == 0)
 344                         sp = current->sas_ss_sp + current->sas_ss_size;
 345         }
 346
 347         sp -= frame_size;
 348         /*
 349          * Align the stack pointer according to the TILE ABI,
 350          * i.e. so that on function entry (sp & 15) == 0.
 351          */
 352         sp &= -16UL;
 353         return (void __user *) sp;
 354 }
 355
 356 int compat_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 357                           sigset_t *set, struct pt_regs *regs)
 358 {
 359         unsigned long restorer;
 360         struct compat_rt_sigframe __user *frame;
 361         int err = 0;
 362         int usig;
 363
 364         frame = compat_get_sigframe(ka, regs, sizeof(*frame));
 365
 366         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 367                 goto give_sigsegv;
 368
 369         usig = current_thread_info()->exec_domain
 370                 && current_thread_info()->exec_domain->signal_invmap
 371                 && sig < 32
 372                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 373                 : sig;
 374
 375         /* Always write at least the signal number for the stack backtracer. */
 376         if (ka->sa.sa_flags & SA_SIGINFO) {
 377                 /* At sigreturn time, restore the callee-save registers too. */
 378                 err |= copy_siginfo_to_user32(&frame->info, info);
 379                 regs->flags |= PT_FLAGS_RESTORE_REGS;
 380         } else {
 381                 err |= __put_user(info->si_signo, &frame->info.si_signo);
 382         }
 383
 384         /* Create the ucontext.  */
 385         err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
 386         err |= __put_user(0, &frame->uc.uc_flags);
 387         err |= __put_user(0, &frame->uc.uc_link);
 388         err |= __put_user(ptr_to_compat((void *)(current->sas_ss_sp)),
 389                           &frame->uc.uc_stack.ss_sp);
 390         err |= __put_user(sas_ss_flags(regs->sp),
 391                           &frame->uc.uc_stack.ss_flags);
 392         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 393         err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
 394         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 395         if (err)
 396                 goto give_sigsegv;
 397
 398         restorer = VDSO_BASE;
 399         if (ka->sa.sa_flags & SA_RESTORER)
 400                 restorer = ptr_to_compat_reg(ka->sa.sa_restorer);
 401
 402         /*
 403          * Set up registers for signal handler.
 404          * Registers that we don't modify keep the value they had from
 405          * user-space at the time we took the signal.
 406          * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
 407          * since some things rely on this (e.g. glibc's debug/segfault.c).
 408          */
 409         regs->pc = ptr_to_compat_reg(ka->sa.sa_handler);
 410         regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
 411         regs->sp = ptr_to_compat_reg(frame);
 412         regs->lr = restorer;
 413         regs->regs[0] = (unsigned long) usig;
 414         regs->regs[1] = ptr_to_compat_reg(&frame->info);
 415         regs->regs[2] = ptr_to_compat_reg(&frame->uc);
 416         regs->flags |= PT_FLAGS_CALLER_SAVES;
 417
 418         /*
 419          * Notify any tracer that was single-stepping it.
 420          * The tracer may want to single-step inside the
 421          * handler too.
 422          */
 423         if (test_thread_flag(TIF_SINGLESTEP))
 424                 ptrace_notify(SIGTRAP);
 425
 426         return 0;
 427
 428 give_sigsegv:
 429         signal_fault("bad setup frame", regs, frame, sig);
 430         return -EFAULT;
 431 }