kernel/compat.c

   1 /*
   2  *  linux/kernel/compat.c
   3  *
   4  *  Kernel compatibililty routines for e.g. 32 bit syscall support
   5  *  on 64 bit kernels.
   6  *
   7  *  Copyright (C) 2002-2003 Stephen Rothwell, IBM Corporation
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2 as
  11  *  published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/linkage.h>
  15 #include <linux/compat.h>
  16 #include <linux/errno.h>
  17 #include <linux/time.h>
  18 #include <linux/signal.h>
  19 #include <linux/sched.h>        /* for MAX_SCHEDULE_TIMEOUT */
  20 #include <linux/syscalls.h>
  21 #include <linux/unistd.h>
  22 #include <linux/security.h>
  23 #include <linux/export.h>
  24 #include <linux/migrate.h>
  25 #include <linux/posix-timers.h>
  26 #include <linux/times.h>
  27 #include <linux/ptrace.h>
  28 #include <linux/gfp.h>
  29
  30 #include <linux/uaccess.h>
  31
  32 static int __compat_get_timeval(struct timeval *tv, const struct old_timeval32 __user *ctv)
  33 {
  34         return (!access_ok(ctv, sizeof(*ctv)) ||
  35                         __get_user(tv->tv_sec, &ctv->tv_sec) ||
  36                         __get_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
  37 }
  38
  39 static int __compat_put_timeval(const struct timeval *tv, struct old_timeval32 __user *ctv)
  40 {
  41         return (!access_ok(ctv, sizeof(*ctv)) ||
  42                         __put_user(tv->tv_sec, &ctv->tv_sec) ||
  43                         __put_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
  44 }
  45
  46 static int __compat_get_timespec(struct timespec *ts, const struct old_timespec32 __user *cts)
  47 {
  48         return (!access_ok(cts, sizeof(*cts)) ||
  49                         __get_user(ts->tv_sec, &cts->tv_sec) ||
  50                         __get_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
  51 }
  52
  53 static int __compat_put_timespec(const struct timespec *ts, struct old_timespec32 __user *cts)
  54 {
  55         return (!access_ok(cts, sizeof(*cts)) ||
  56                         __put_user(ts->tv_sec, &cts->tv_sec) ||
  57                         __put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
  58 }
  59
  60 int compat_get_timeval(struct timeval *tv, const void __user *utv)
  61 {
  62         if (COMPAT_USE_64BIT_TIME)
  63                 return copy_from_user(tv, utv, sizeof(*tv)) ? -EFAULT : 0;
  64         else
  65                 return __compat_get_timeval(tv, utv);
  66 }
  67 EXPORT_SYMBOL_GPL(compat_get_timeval);
  68
  69 int compat_put_timeval(const struct timeval *tv, void __user *utv)
  70 {
  71         if (COMPAT_USE_64BIT_TIME)
  72                 return copy_to_user(utv, tv, sizeof(*tv)) ? -EFAULT : 0;
  73         else
  74                 return __compat_put_timeval(tv, utv);
  75 }
  76 EXPORT_SYMBOL_GPL(compat_put_timeval);
  77
  78 int compat_get_timespec(struct timespec *ts, const void __user *uts)
  79 {
  80         if (COMPAT_USE_64BIT_TIME)
  81                 return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
  82         else
  83                 return __compat_get_timespec(ts, uts);
  84 }
  85 EXPORT_SYMBOL_GPL(compat_get_timespec);
  86
  87 int compat_put_timespec(const struct timespec *ts, void __user *uts)
  88 {
  89         if (COMPAT_USE_64BIT_TIME)
  90                 return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
  91         else
  92                 return __compat_put_timespec(ts, uts);
  93 }
  94 EXPORT_SYMBOL_GPL(compat_put_timespec);
  95
  96 int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i)
  97 {
  98         struct compat_itimerval v32;
  99
 100         if (copy_from_user(&v32, i, sizeof(struct compat_itimerval)))
 101                 return -EFAULT;
 102         o->it_interval.tv_sec = v32.it_interval.tv_sec;
 103         o->it_interval.tv_usec = v32.it_interval.tv_usec;
 104         o->it_value.tv_sec = v32.it_value.tv_sec;
 105         o->it_value.tv_usec = v32.it_value.tv_usec;
 106         return 0;
 107 }
 108
 109 int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)
 110 {
 111         struct compat_itimerval v32;
 112
 113         v32.it_interval.tv_sec = i->it_interval.tv_sec;
 114         v32.it_interval.tv_usec = i->it_interval.tv_usec;
 115         v32.it_value.tv_sec = i->it_value.tv_sec;
 116         v32.it_value.tv_usec = i->it_value.tv_usec;
 117         return copy_to_user(o, &v32, sizeof(struct compat_itimerval)) ? -EFAULT : 0;
 118 }
 119
 120 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
 121
 122 /*
 123  * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
 124  * blocked set of signals to the supplied signal set
 125  */
 126 static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
 127 {
 128         memcpy(blocked->sig, &set, sizeof(set));
 129 }
 130
 131 COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
 132                        compat_old_sigset_t __user *, nset,
 133                        compat_old_sigset_t __user *, oset)
 134 {
 135         old_sigset_t old_set, new_set;
 136         sigset_t new_blocked;
 137
 138         old_set = current->blocked.sig[0];
 139
 140         if (nset) {
 141                 if (get_user(new_set, nset))
 142                         return -EFAULT;
 143                 new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
 144
 145                 new_blocked = current->blocked;
 146
 147                 switch (how) {
 148                 case SIG_BLOCK:
 149                         sigaddsetmask(&new_blocked, new_set);
 150                         break;
 151                 case SIG_UNBLOCK:
 152                         sigdelsetmask(&new_blocked, new_set);
 153                         break;
 154                 case SIG_SETMASK:
 155                         compat_sig_setmask(&new_blocked, new_set);
 156                         break;
 157                 default:
 158                         return -EINVAL;
 159                 }
 160
 161                 set_current_blocked(&new_blocked);
 162         }
 163
 164         if (oset) {
 165                 if (put_user(old_set, oset))
 166                         return -EFAULT;
 167         }
 168
 169         return 0;
 170 }
 171
 172 #endif
 173
 174 int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
 175 {
 176         struct compat_rusage r32;
 177         memset(&r32, 0, sizeof(r32));
 178         r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
 179         r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
 180         r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
 181         r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
 182         r32.ru_maxrss = r->ru_maxrss;
 183         r32.ru_ixrss = r->ru_ixrss;
 184         r32.ru_idrss = r->ru_idrss;
 185         r32.ru_isrss = r->ru_isrss;
 186         r32.ru_minflt = r->ru_minflt;
 187         r32.ru_majflt = r->ru_majflt;
 188         r32.ru_nswap = r->ru_nswap;
 189         r32.ru_inblock = r->ru_inblock;
 190         r32.ru_oublock = r->ru_oublock;
 191         r32.ru_msgsnd = r->ru_msgsnd;
 192         r32.ru_msgrcv = r->ru_msgrcv;
 193         r32.ru_nsignals = r->ru_nsignals;
 194         r32.ru_nvcsw = r->ru_nvcsw;
 195         r32.ru_nivcsw = r->ru_nivcsw;
 196         if (copy_to_user(ru, &r32, sizeof(r32)))
 197                 return -EFAULT;
 198         return 0;
 199 }
 200
 201 static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
 202                                     unsigned len, struct cpumask *new_mask)
 203 {
 204         unsigned long *k;
 205
 206         if (len < cpumask_size())
 207                 memset(new_mask, 0, cpumask_size());
 208         else if (len > cpumask_size())
 209                 len = cpumask_size();
 210
 211         k = cpumask_bits(new_mask);
 212         return compat_get_bitmap(k, user_mask_ptr, len * 8);
 213 }
 214
 215 COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
 216                        unsigned int, len,
 217                        compat_ulong_t __user *, user_mask_ptr)
 218 {
 219         cpumask_var_t new_mask;
 220         int retval;
 221
 222         if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
 223                 return -ENOMEM;
 224
 225         retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
 226         if (retval)
 227                 goto out;
 228
 229         retval = sched_setaffinity(pid, new_mask);
 230 out:
 231         free_cpumask_var(new_mask);
 232         return retval;
 233 }
 234
 235 COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t,  pid, unsigned int, len,
 236                        compat_ulong_t __user *, user_mask_ptr)
 237 {
 238         int ret;
 239         cpumask_var_t mask;
 240
 241         if ((len * BITS_PER_BYTE) < nr_cpu_ids)
 242                 return -EINVAL;
 243         if (len & (sizeof(compat_ulong_t)-1))
 244                 return -EINVAL;
 245
 246         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 247                 return -ENOMEM;
 248
 249         ret = sched_getaffinity(pid, mask);
 250         if (ret == 0) {
 251                 unsigned int retlen = min(len, cpumask_size());
 252
 253                 if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
 254                         ret = -EFAULT;
 255                 else
 256                         ret = retlen;
 257         }
 258         free_cpumask_var(mask);
 259
 260         return ret;
 261 }
 262
 263 /*
 264  * We currently only need the following fields from the sigevent
 265  * structure: sigev_value, sigev_signo, sig_notify and (sometimes
 266  * sigev_notify_thread_id).  The others are handled in user mode.
 267  * We also assume that copying sigev_value.sival_int is sufficient
 268  * to keep all the bits of sigev_value.sival_ptr intact.
 269  */
 270 int get_compat_sigevent(struct sigevent *event,
 271                 const struct compat_sigevent __user *u_event)
 272 {
 273         memset(event, 0, sizeof(*event));
 274         return (!access_ok(u_event, sizeof(*u_event)) ||
 275                 __get_user(event->sigev_value.sival_int,
 276                         &u_event->sigev_value.sival_int) ||
 277                 __get_user(event->sigev_signo, &u_event->sigev_signo) ||
 278                 __get_user(event->sigev_notify, &u_event->sigev_notify) ||
 279                 __get_user(event->sigev_notify_thread_id,
 280                         &u_event->sigev_notify_thread_id))
 281                 ? -EFAULT : 0;
 282 }
 283
 284 long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
 285                        unsigned long bitmap_size)
 286 {
 287         unsigned long nr_compat_longs;
 288
 289         /* align bitmap up to nearest compat_long_t boundary */
 290         bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 291         nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
 292
 293         if (!user_access_begin(umask, bitmap_size / 8))
 294                 return -EFAULT;
 295
 296         while (nr_compat_longs > 1) {
 297                 compat_ulong_t l1, l2;
 298                 unsafe_get_user(l1, umask++, Efault);
 299                 unsafe_get_user(l2, umask++, Efault);
 300                 *mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
 301                 nr_compat_longs -= 2;
 302         }
 303         if (nr_compat_longs)
 304                 unsafe_get_user(*mask, umask++, Efault);
 305         user_access_end();
 306         return 0;
 307
 308 Efault:
 309         user_access_end();
 310         return -EFAULT;
 311 }
 312
 313 long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
 314                        unsigned long bitmap_size)
 315 {
 316         unsigned long nr_compat_longs;
 317
 318         /* align bitmap up to nearest compat_long_t boundary */
 319         bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 320         nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
 321
 322         if (!user_access_begin(umask, bitmap_size / 8))
 323                 return -EFAULT;
 324
 325         while (nr_compat_longs > 1) {
 326                 unsigned long m = *mask++;
 327                 unsafe_put_user((compat_ulong_t)m, umask++, Efault);
 328                 unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
 329                 nr_compat_longs -= 2;
 330         }
 331         if (nr_compat_longs)
 332                 unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
 333         user_access_end();
 334         return 0;
 335 Efault:
 336         user_access_end();
 337         return -EFAULT;
 338 }
 339
 340 int
 341 get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
 342 {
 343 #ifdef __BIG_ENDIAN
 344         compat_sigset_t v;
 345         if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
 346                 return -EFAULT;
 347         switch (_NSIG_WORDS) {
 348         case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
 349         case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
 350         case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
 351         case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );
 352         }
 353 #else
 354         if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
 355                 return -EFAULT;
 356 #endif
 357         return 0;
 358 }
 359 EXPORT_SYMBOL_GPL(get_compat_sigset);
 360
 361 /*
 362  * Allocate user-space memory for the duration of a single system call,
 363  * in order to marshall parameters inside a compat thunk.
 364  */
 365 void __user *compat_alloc_user_space(unsigned long len)
 366 {
 367         void __user *ptr;
 368
 369         /* If len would occupy more than half of the entire compat space... */
 370         if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
 371                 return NULL;
 372
 373         ptr = arch_compat_alloc_user_space(len);
 374
 375         if (unlikely(!access_ok(ptr, len)))
 376                 return NULL;
 377
 378         return ptr;
 379 }
 380 EXPORT_SYMBOL_GPL(compat_alloc_user_space);