kernel/compat.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/kernel/compat.c
   4  *
   5  *  Kernel compatibililty routines for e.g. 32 bit syscall support
   6  *  on 64 bit kernels.
   7  *
   8  *  Copyright (C) 2002-2003 Stephen Rothwell, IBM Corporation
   9  */
  10
  11 #include <linux/linkage.h>
  12 #include <linux/compat.h>
  13 #include <linux/errno.h>
  14 #include <linux/time.h>
  15 #include <linux/signal.h>
  16 #include <linux/sched.h>        /* for MAX_SCHEDULE_TIMEOUT */
  17 #include <linux/syscalls.h>
  18 #include <linux/unistd.h>
  19 #include <linux/security.h>
  20 #include <linux/export.h>
  21 #include <linux/migrate.h>
  22 #include <linux/posix-timers.h>
  23 #include <linux/times.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/gfp.h>
  26
  27 #include <linux/uaccess.h>
  28
  29 static int __compat_get_timeval(struct timeval *tv, const struct old_timeval32 __user *ctv)
  30 {
  31         return (!access_ok(ctv, sizeof(*ctv)) ||
  32                         __get_user(tv->tv_sec, &ctv->tv_sec) ||
  33                         __get_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
  34 }
  35
  36 static int __compat_put_timeval(const struct timeval *tv, struct old_timeval32 __user *ctv)
  37 {
  38         return (!access_ok(ctv, sizeof(*ctv)) ||
  39                         __put_user(tv->tv_sec, &ctv->tv_sec) ||
  40                         __put_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
  41 }
  42
  43 static int __compat_get_timespec(struct timespec *ts, const struct old_timespec32 __user *cts)
  44 {
  45         return (!access_ok(cts, sizeof(*cts)) ||
  46                         __get_user(ts->tv_sec, &cts->tv_sec) ||
  47                         __get_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
  48 }
  49
  50 static int __compat_put_timespec(const struct timespec *ts, struct old_timespec32 __user *cts)
  51 {
  52         return (!access_ok(cts, sizeof(*cts)) ||
  53                         __put_user(ts->tv_sec, &cts->tv_sec) ||
  54                         __put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
  55 }
  56
  57 int compat_get_timeval(struct timeval *tv, const void __user *utv)
  58 {
  59         if (COMPAT_USE_64BIT_TIME)
  60                 return copy_from_user(tv, utv, sizeof(*tv)) ? -EFAULT : 0;
  61         else
  62                 return __compat_get_timeval(tv, utv);
  63 }
  64 EXPORT_SYMBOL_GPL(compat_get_timeval);
  65
  66 int compat_put_timeval(const struct timeval *tv, void __user *utv)
  67 {
  68         if (COMPAT_USE_64BIT_TIME)
  69                 return copy_to_user(utv, tv, sizeof(*tv)) ? -EFAULT : 0;
  70         else
  71                 return __compat_put_timeval(tv, utv);
  72 }
  73 EXPORT_SYMBOL_GPL(compat_put_timeval);
  74
  75 int compat_get_timespec(struct timespec *ts, const void __user *uts)
  76 {
  77         if (COMPAT_USE_64BIT_TIME)
  78                 return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
  79         else
  80                 return __compat_get_timespec(ts, uts);
  81 }
  82 EXPORT_SYMBOL_GPL(compat_get_timespec);
  83
  84 int compat_put_timespec(const struct timespec *ts, void __user *uts)
  85 {
  86         if (COMPAT_USE_64BIT_TIME)
  87                 return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
  88         else
  89                 return __compat_put_timespec(ts, uts);
  90 }
  91 EXPORT_SYMBOL_GPL(compat_put_timespec);
  92
  93 int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i)
  94 {
  95         struct compat_itimerval v32;
  96
  97         if (copy_from_user(&v32, i, sizeof(struct compat_itimerval)))
  98                 return -EFAULT;
  99         o->it_interval.tv_sec = v32.it_interval.tv_sec;
 100         o->it_interval.tv_usec = v32.it_interval.tv_usec;
 101         o->it_value.tv_sec = v32.it_value.tv_sec;
 102         o->it_value.tv_usec = v32.it_value.tv_usec;
 103         return 0;
 104 }
 105
 106 int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)
 107 {
 108         struct compat_itimerval v32;
 109
 110         v32.it_interval.tv_sec = i->it_interval.tv_sec;
 111         v32.it_interval.tv_usec = i->it_interval.tv_usec;
 112         v32.it_value.tv_sec = i->it_value.tv_sec;
 113         v32.it_value.tv_usec = i->it_value.tv_usec;
 114         return copy_to_user(o, &v32, sizeof(struct compat_itimerval)) ? -EFAULT : 0;
 115 }
 116
 117 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
 118
 119 /*
 120  * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
 121  * blocked set of signals to the supplied signal set
 122  */
 123 static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
 124 {
 125         memcpy(blocked->sig, &set, sizeof(set));
 126 }
 127
 128 COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
 129                        compat_old_sigset_t __user *, nset,
 130                        compat_old_sigset_t __user *, oset)
 131 {
 132         old_sigset_t old_set, new_set;
 133         sigset_t new_blocked;
 134
 135         old_set = current->blocked.sig[0];
 136
 137         if (nset) {
 138                 if (get_user(new_set, nset))
 139                         return -EFAULT;
 140                 new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
 141
 142                 new_blocked = current->blocked;
 143
 144                 switch (how) {
 145                 case SIG_BLOCK:
 146                         sigaddsetmask(&new_blocked, new_set);
 147                         break;
 148                 case SIG_UNBLOCK:
 149                         sigdelsetmask(&new_blocked, new_set);
 150                         break;
 151                 case SIG_SETMASK:
 152                         compat_sig_setmask(&new_blocked, new_set);
 153                         break;
 154                 default:
 155                         return -EINVAL;
 156                 }
 157
 158                 set_current_blocked(&new_blocked);
 159         }
 160
 161         if (oset) {
 162                 if (put_user(old_set, oset))
 163                         return -EFAULT;
 164         }
 165
 166         return 0;
 167 }
 168
 169 #endif
 170
 171 int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
 172 {
 173         struct compat_rusage r32;
 174         memset(&r32, 0, sizeof(r32));
 175         r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
 176         r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
 177         r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
 178         r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
 179         r32.ru_maxrss = r->ru_maxrss;
 180         r32.ru_ixrss = r->ru_ixrss;
 181         r32.ru_idrss = r->ru_idrss;
 182         r32.ru_isrss = r->ru_isrss;
 183         r32.ru_minflt = r->ru_minflt;
 184         r32.ru_majflt = r->ru_majflt;
 185         r32.ru_nswap = r->ru_nswap;
 186         r32.ru_inblock = r->ru_inblock;
 187         r32.ru_oublock = r->ru_oublock;
 188         r32.ru_msgsnd = r->ru_msgsnd;
 189         r32.ru_msgrcv = r->ru_msgrcv;
 190         r32.ru_nsignals = r->ru_nsignals;
 191         r32.ru_nvcsw = r->ru_nvcsw;
 192         r32.ru_nivcsw = r->ru_nivcsw;
 193         if (copy_to_user(ru, &r32, sizeof(r32)))
 194                 return -EFAULT;
 195         return 0;
 196 }
 197
 198 static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
 199                                     unsigned len, struct cpumask *new_mask)
 200 {
 201         unsigned long *k;
 202
 203         if (len < cpumask_size())
 204                 memset(new_mask, 0, cpumask_size());
 205         else if (len > cpumask_size())
 206                 len = cpumask_size();
 207
 208         k = cpumask_bits(new_mask);
 209         return compat_get_bitmap(k, user_mask_ptr, len * 8);
 210 }
 211
 212 COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
 213                        unsigned int, len,
 214                        compat_ulong_t __user *, user_mask_ptr)
 215 {
 216         cpumask_var_t new_mask;
 217         int retval;
 218
 219         if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
 220                 return -ENOMEM;
 221
 222         retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
 223         if (retval)
 224                 goto out;
 225
 226         retval = sched_setaffinity(pid, new_mask);
 227 out:
 228         free_cpumask_var(new_mask);
 229         return retval;
 230 }
 231
 232 COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t,  pid, unsigned int, len,
 233                        compat_ulong_t __user *, user_mask_ptr)
 234 {
 235         int ret;
 236         cpumask_var_t mask;
 237
 238         if ((len * BITS_PER_BYTE) < nr_cpu_ids)
 239                 return -EINVAL;
 240         if (len & (sizeof(compat_ulong_t)-1))
 241                 return -EINVAL;
 242
 243         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 244                 return -ENOMEM;
 245
 246         ret = sched_getaffinity(pid, mask);
 247         if (ret == 0) {
 248                 unsigned int retlen = min(len, cpumask_size());
 249
 250                 if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
 251                         ret = -EFAULT;
 252                 else
 253                         ret = retlen;
 254         }
 255         free_cpumask_var(mask);
 256
 257         return ret;
 258 }
 259
 260 /*
 261  * We currently only need the following fields from the sigevent
 262  * structure: sigev_value, sigev_signo, sig_notify and (sometimes
 263  * sigev_notify_thread_id).  The others are handled in user mode.
 264  * We also assume that copying sigev_value.sival_int is sufficient
 265  * to keep all the bits of sigev_value.sival_ptr intact.
 266  */
 267 int get_compat_sigevent(struct sigevent *event,
 268                 const struct compat_sigevent __user *u_event)
 269 {
 270         memset(event, 0, sizeof(*event));
 271         return (!access_ok(u_event, sizeof(*u_event)) ||
 272                 __get_user(event->sigev_value.sival_int,
 273                         &u_event->sigev_value.sival_int) ||
 274                 __get_user(event->sigev_signo, &u_event->sigev_signo) ||
 275                 __get_user(event->sigev_notify, &u_event->sigev_notify) ||
 276                 __get_user(event->sigev_notify_thread_id,
 277                         &u_event->sigev_notify_thread_id))
 278                 ? -EFAULT : 0;
 279 }
 280
 281 long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
 282                        unsigned long bitmap_size)
 283 {
 284         unsigned long nr_compat_longs;
 285
 286         /* align bitmap up to nearest compat_long_t boundary */
 287         bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 288         nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
 289
 290         if (!user_access_begin(umask, bitmap_size / 8))
 291                 return -EFAULT;
 292
 293         while (nr_compat_longs > 1) {
 294                 compat_ulong_t l1, l2;
 295                 unsafe_get_user(l1, umask++, Efault);
 296                 unsafe_get_user(l2, umask++, Efault);
 297                 *mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
 298                 nr_compat_longs -= 2;
 299         }
 300         if (nr_compat_longs)
 301                 unsafe_get_user(*mask, umask++, Efault);
 302         user_access_end();
 303         return 0;
 304
 305 Efault:
 306         user_access_end();
 307         return -EFAULT;
 308 }
 309
 310 long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
 311                        unsigned long bitmap_size)
 312 {
 313         unsigned long nr_compat_longs;
 314
 315         /* align bitmap up to nearest compat_long_t boundary */
 316         bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 317         nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
 318
 319         if (!user_access_begin(umask, bitmap_size / 8))
 320                 return -EFAULT;
 321
 322         while (nr_compat_longs > 1) {
 323                 unsigned long m = *mask++;
 324                 unsafe_put_user((compat_ulong_t)m, umask++, Efault);
 325                 unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
 326                 nr_compat_longs -= 2;
 327         }
 328         if (nr_compat_longs)
 329                 unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
 330         user_access_end();
 331         return 0;
 332 Efault:
 333         user_access_end();
 334         return -EFAULT;
 335 }
 336
 337 int
 338 get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
 339 {
 340 #ifdef __BIG_ENDIAN
 341         compat_sigset_t v;
 342         if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
 343                 return -EFAULT;
 344         switch (_NSIG_WORDS) {
 345         case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
 346                 /* fall through */
 347         case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
 348                 /* fall through */
 349         case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
 350                 /* fall through */
 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);