linux/kernel/compat.c
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   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
  29static 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
  36static 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
  43static 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
  50static 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
  57int 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}
  64EXPORT_SYMBOL_GPL(compat_get_timeval);
  65
  66int 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}
  73EXPORT_SYMBOL_GPL(compat_put_timeval);
  74
  75int 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}
  82EXPORT_SYMBOL_GPL(compat_get_timespec);
  83
  84int 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}
  91EXPORT_SYMBOL_GPL(compat_put_timespec);
  92
  93int 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
 106int 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 */
 123static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
 124{
 125        memcpy(blocked->sig, &set, sizeof(set));
 126}
 127
 128COMPAT_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
 171int 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
 198static 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
 212COMPAT_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);
 227out:
 228        free_cpumask_var(new_mask);
 229        return retval;
 230}
 231
 232COMPAT_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 */
 267int 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
 281long 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
 305Efault:
 306        user_access_end();
 307        return -EFAULT;
 308}
 309
 310long 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;
 332Efault:
 333        user_access_end();
 334        return -EFAULT;
 335}
 336
 337int
 338get_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}
 359EXPORT_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 */
 365void __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}
 380EXPORT_SYMBOL_GPL(compat_alloc_user_space);
 381