linux/kernel/compat.c
<<
>>
Prefs
   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/timex.h>
  24#include <linux/export.h>
  25#include <linux/migrate.h>
  26#include <linux/posix-timers.h>
  27#include <linux/times.h>
  28#include <linux/ptrace.h>
  29#include <linux/gfp.h>
  30
  31#include <linux/uaccess.h>
  32
  33int compat_get_timex(struct timex *txc, const struct compat_timex __user *utp)
  34{
  35        struct compat_timex tx32;
  36
  37        memset(txc, 0, sizeof(struct timex));
  38        if (copy_from_user(&tx32, utp, sizeof(struct compat_timex)))
  39                return -EFAULT;
  40
  41        txc->modes = tx32.modes;
  42        txc->offset = tx32.offset;
  43        txc->freq = tx32.freq;
  44        txc->maxerror = tx32.maxerror;
  45        txc->esterror = tx32.esterror;
  46        txc->status = tx32.status;
  47        txc->constant = tx32.constant;
  48        txc->precision = tx32.precision;
  49        txc->tolerance = tx32.tolerance;
  50        txc->time.tv_sec = tx32.time.tv_sec;
  51        txc->time.tv_usec = tx32.time.tv_usec;
  52        txc->tick = tx32.tick;
  53        txc->ppsfreq = tx32.ppsfreq;
  54        txc->jitter = tx32.jitter;
  55        txc->shift = tx32.shift;
  56        txc->stabil = tx32.stabil;
  57        txc->jitcnt = tx32.jitcnt;
  58        txc->calcnt = tx32.calcnt;
  59        txc->errcnt = tx32.errcnt;
  60        txc->stbcnt = tx32.stbcnt;
  61
  62        return 0;
  63}
  64
  65int compat_put_timex(struct compat_timex __user *utp, const struct timex *txc)
  66{
  67        struct compat_timex tx32;
  68
  69        memset(&tx32, 0, sizeof(struct compat_timex));
  70        tx32.modes = txc->modes;
  71        tx32.offset = txc->offset;
  72        tx32.freq = txc->freq;
  73        tx32.maxerror = txc->maxerror;
  74        tx32.esterror = txc->esterror;
  75        tx32.status = txc->status;
  76        tx32.constant = txc->constant;
  77        tx32.precision = txc->precision;
  78        tx32.tolerance = txc->tolerance;
  79        tx32.time.tv_sec = txc->time.tv_sec;
  80        tx32.time.tv_usec = txc->time.tv_usec;
  81        tx32.tick = txc->tick;
  82        tx32.ppsfreq = txc->ppsfreq;
  83        tx32.jitter = txc->jitter;
  84        tx32.shift = txc->shift;
  85        tx32.stabil = txc->stabil;
  86        tx32.jitcnt = txc->jitcnt;
  87        tx32.calcnt = txc->calcnt;
  88        tx32.errcnt = txc->errcnt;
  89        tx32.stbcnt = txc->stbcnt;
  90        tx32.tai = txc->tai;
  91        if (copy_to_user(utp, &tx32, sizeof(struct compat_timex)))
  92                return -EFAULT;
  93        return 0;
  94}
  95
  96static int __compat_get_timeval(struct timeval *tv, const struct compat_timeval __user *ctv)
  97{
  98        return (!access_ok(VERIFY_READ, ctv, sizeof(*ctv)) ||
  99                        __get_user(tv->tv_sec, &ctv->tv_sec) ||
 100                        __get_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
 101}
 102
 103static int __compat_put_timeval(const struct timeval *tv, struct compat_timeval __user *ctv)
 104{
 105        return (!access_ok(VERIFY_WRITE, ctv, sizeof(*ctv)) ||
 106                        __put_user(tv->tv_sec, &ctv->tv_sec) ||
 107                        __put_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
 108}
 109
 110static int __compat_get_timespec(struct timespec *ts, const struct compat_timespec __user *cts)
 111{
 112        return (!access_ok(VERIFY_READ, cts, sizeof(*cts)) ||
 113                        __get_user(ts->tv_sec, &cts->tv_sec) ||
 114                        __get_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
 115}
 116
 117static int __compat_put_timespec(const struct timespec *ts, struct compat_timespec __user *cts)
 118{
 119        return (!access_ok(VERIFY_WRITE, cts, sizeof(*cts)) ||
 120                        __put_user(ts->tv_sec, &cts->tv_sec) ||
 121                        __put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
 122}
 123
 124static int __compat_get_timespec64(struct timespec64 *ts64,
 125                                   const struct compat_timespec __user *cts)
 126{
 127        struct compat_timespec ts;
 128        int ret;
 129
 130        ret = copy_from_user(&ts, cts, sizeof(ts));
 131        if (ret)
 132                return -EFAULT;
 133
 134        ts64->tv_sec = ts.tv_sec;
 135        ts64->tv_nsec = ts.tv_nsec;
 136
 137        return 0;
 138}
 139
 140static int __compat_put_timespec64(const struct timespec64 *ts64,
 141                                   struct compat_timespec __user *cts)
 142{
 143        struct compat_timespec ts = {
 144                .tv_sec = ts64->tv_sec,
 145                .tv_nsec = ts64->tv_nsec
 146        };
 147        return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0;
 148}
 149
 150int compat_get_timespec64(struct timespec64 *ts, const void __user *uts)
 151{
 152        if (COMPAT_USE_64BIT_TIME)
 153                return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
 154        else
 155                return __compat_get_timespec64(ts, uts);
 156}
 157EXPORT_SYMBOL_GPL(compat_get_timespec64);
 158
 159int compat_put_timespec64(const struct timespec64 *ts, void __user *uts)
 160{
 161        if (COMPAT_USE_64BIT_TIME)
 162                return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
 163        else
 164                return __compat_put_timespec64(ts, uts);
 165}
 166EXPORT_SYMBOL_GPL(compat_put_timespec64);
 167
 168int compat_get_timeval(struct timeval *tv, const void __user *utv)
 169{
 170        if (COMPAT_USE_64BIT_TIME)
 171                return copy_from_user(tv, utv, sizeof(*tv)) ? -EFAULT : 0;
 172        else
 173                return __compat_get_timeval(tv, utv);
 174}
 175EXPORT_SYMBOL_GPL(compat_get_timeval);
 176
 177int compat_put_timeval(const struct timeval *tv, void __user *utv)
 178{
 179        if (COMPAT_USE_64BIT_TIME)
 180                return copy_to_user(utv, tv, sizeof(*tv)) ? -EFAULT : 0;
 181        else
 182                return __compat_put_timeval(tv, utv);
 183}
 184EXPORT_SYMBOL_GPL(compat_put_timeval);
 185
 186int compat_get_timespec(struct timespec *ts, const void __user *uts)
 187{
 188        if (COMPAT_USE_64BIT_TIME)
 189                return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
 190        else
 191                return __compat_get_timespec(ts, uts);
 192}
 193EXPORT_SYMBOL_GPL(compat_get_timespec);
 194
 195int compat_put_timespec(const struct timespec *ts, void __user *uts)
 196{
 197        if (COMPAT_USE_64BIT_TIME)
 198                return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
 199        else
 200                return __compat_put_timespec(ts, uts);
 201}
 202EXPORT_SYMBOL_GPL(compat_put_timespec);
 203
 204int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i)
 205{
 206        struct compat_itimerval v32;
 207
 208        if (copy_from_user(&v32, i, sizeof(struct compat_itimerval)))
 209                return -EFAULT;
 210        o->it_interval.tv_sec = v32.it_interval.tv_sec;
 211        o->it_interval.tv_usec = v32.it_interval.tv_usec;
 212        o->it_value.tv_sec = v32.it_value.tv_sec;
 213        o->it_value.tv_usec = v32.it_value.tv_usec;
 214        return 0;
 215}
 216
 217int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)
 218{
 219        struct compat_itimerval v32;
 220
 221        v32.it_interval.tv_sec = i->it_interval.tv_sec;
 222        v32.it_interval.tv_usec = i->it_interval.tv_usec;
 223        v32.it_value.tv_sec = i->it_value.tv_sec;
 224        v32.it_value.tv_usec = i->it_value.tv_usec;
 225        return copy_to_user(o, &v32, sizeof(struct compat_itimerval)) ? -EFAULT : 0;
 226}
 227
 228#ifdef __ARCH_WANT_SYS_SIGPROCMASK
 229
 230/*
 231 * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
 232 * blocked set of signals to the supplied signal set
 233 */
 234static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
 235{
 236        memcpy(blocked->sig, &set, sizeof(set));
 237}
 238
 239COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
 240                       compat_old_sigset_t __user *, nset,
 241                       compat_old_sigset_t __user *, oset)
 242{
 243        old_sigset_t old_set, new_set;
 244        sigset_t new_blocked;
 245
 246        old_set = current->blocked.sig[0];
 247
 248        if (nset) {
 249                if (get_user(new_set, nset))
 250                        return -EFAULT;
 251                new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
 252
 253                new_blocked = current->blocked;
 254
 255                switch (how) {
 256                case SIG_BLOCK:
 257                        sigaddsetmask(&new_blocked, new_set);
 258                        break;
 259                case SIG_UNBLOCK:
 260                        sigdelsetmask(&new_blocked, new_set);
 261                        break;
 262                case SIG_SETMASK:
 263                        compat_sig_setmask(&new_blocked, new_set);
 264                        break;
 265                default:
 266                        return -EINVAL;
 267                }
 268
 269                set_current_blocked(&new_blocked);
 270        }
 271
 272        if (oset) {
 273                if (put_user(old_set, oset))
 274                        return -EFAULT;
 275        }
 276
 277        return 0;
 278}
 279
 280#endif
 281
 282int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
 283{
 284        struct compat_rusage r32;
 285        memset(&r32, 0, sizeof(r32));
 286        r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
 287        r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
 288        r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
 289        r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
 290        r32.ru_maxrss = r->ru_maxrss;
 291        r32.ru_ixrss = r->ru_ixrss;
 292        r32.ru_idrss = r->ru_idrss;
 293        r32.ru_isrss = r->ru_isrss;
 294        r32.ru_minflt = r->ru_minflt;
 295        r32.ru_majflt = r->ru_majflt;
 296        r32.ru_nswap = r->ru_nswap;
 297        r32.ru_inblock = r->ru_inblock;
 298        r32.ru_oublock = r->ru_oublock;
 299        r32.ru_msgsnd = r->ru_msgsnd;
 300        r32.ru_msgrcv = r->ru_msgrcv;
 301        r32.ru_nsignals = r->ru_nsignals;
 302        r32.ru_nvcsw = r->ru_nvcsw;
 303        r32.ru_nivcsw = r->ru_nivcsw;
 304        if (copy_to_user(ru, &r32, sizeof(r32)))
 305                return -EFAULT;
 306        return 0;
 307}
 308
 309static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
 310                                    unsigned len, struct cpumask *new_mask)
 311{
 312        unsigned long *k;
 313
 314        if (len < cpumask_size())
 315                memset(new_mask, 0, cpumask_size());
 316        else if (len > cpumask_size())
 317                len = cpumask_size();
 318
 319        k = cpumask_bits(new_mask);
 320        return compat_get_bitmap(k, user_mask_ptr, len * 8);
 321}
 322
 323COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
 324                       unsigned int, len,
 325                       compat_ulong_t __user *, user_mask_ptr)
 326{
 327        cpumask_var_t new_mask;
 328        int retval;
 329
 330        if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
 331                return -ENOMEM;
 332
 333        retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
 334        if (retval)
 335                goto out;
 336
 337        retval = sched_setaffinity(pid, new_mask);
 338out:
 339        free_cpumask_var(new_mask);
 340        return retval;
 341}
 342
 343COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t,  pid, unsigned int, len,
 344                       compat_ulong_t __user *, user_mask_ptr)
 345{
 346        int ret;
 347        cpumask_var_t mask;
 348
 349        if ((len * BITS_PER_BYTE) < nr_cpu_ids)
 350                return -EINVAL;
 351        if (len & (sizeof(compat_ulong_t)-1))
 352                return -EINVAL;
 353
 354        if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 355                return -ENOMEM;
 356
 357        ret = sched_getaffinity(pid, mask);
 358        if (ret == 0) {
 359                unsigned int retlen = min(len, cpumask_size());
 360
 361                if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
 362                        ret = -EFAULT;
 363                else
 364                        ret = retlen;
 365        }
 366        free_cpumask_var(mask);
 367
 368        return ret;
 369}
 370
 371int get_compat_itimerspec64(struct itimerspec64 *its,
 372                        const struct compat_itimerspec __user *uits)
 373{
 374
 375        if (__compat_get_timespec64(&its->it_interval, &uits->it_interval) ||
 376            __compat_get_timespec64(&its->it_value, &uits->it_value))
 377                return -EFAULT;
 378        return 0;
 379}
 380EXPORT_SYMBOL_GPL(get_compat_itimerspec64);
 381
 382int put_compat_itimerspec64(const struct itimerspec64 *its,
 383                        struct compat_itimerspec __user *uits)
 384{
 385        if (__compat_put_timespec64(&its->it_interval, &uits->it_interval) ||
 386            __compat_put_timespec64(&its->it_value, &uits->it_value))
 387                return -EFAULT;
 388        return 0;
 389}
 390EXPORT_SYMBOL_GPL(put_compat_itimerspec64);
 391
 392/*
 393 * We currently only need the following fields from the sigevent
 394 * structure: sigev_value, sigev_signo, sig_notify and (sometimes
 395 * sigev_notify_thread_id).  The others are handled in user mode.
 396 * We also assume that copying sigev_value.sival_int is sufficient
 397 * to keep all the bits of sigev_value.sival_ptr intact.
 398 */
 399int get_compat_sigevent(struct sigevent *event,
 400                const struct compat_sigevent __user *u_event)
 401{
 402        memset(event, 0, sizeof(*event));
 403        return (!access_ok(VERIFY_READ, u_event, sizeof(*u_event)) ||
 404                __get_user(event->sigev_value.sival_int,
 405                        &u_event->sigev_value.sival_int) ||
 406                __get_user(event->sigev_signo, &u_event->sigev_signo) ||
 407                __get_user(event->sigev_notify, &u_event->sigev_notify) ||
 408                __get_user(event->sigev_notify_thread_id,
 409                        &u_event->sigev_notify_thread_id))
 410                ? -EFAULT : 0;
 411}
 412
 413long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
 414                       unsigned long bitmap_size)
 415{
 416        unsigned long nr_compat_longs;
 417
 418        /* align bitmap up to nearest compat_long_t boundary */
 419        bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 420        nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
 421
 422        if (!access_ok(VERIFY_READ, umask, bitmap_size / 8))
 423                return -EFAULT;
 424
 425        user_access_begin();
 426        while (nr_compat_longs > 1) {
 427                compat_ulong_t l1, l2;
 428                unsafe_get_user(l1, umask++, Efault);
 429                unsafe_get_user(l2, umask++, Efault);
 430                *mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
 431                nr_compat_longs -= 2;
 432        }
 433        if (nr_compat_longs)
 434                unsafe_get_user(*mask, umask++, Efault);
 435        user_access_end();
 436        return 0;
 437
 438Efault:
 439        user_access_end();
 440        return -EFAULT;
 441}
 442
 443long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
 444                       unsigned long bitmap_size)
 445{
 446        unsigned long nr_compat_longs;
 447
 448        /* align bitmap up to nearest compat_long_t boundary */
 449        bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 450        nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
 451
 452        if (!access_ok(VERIFY_WRITE, umask, bitmap_size / 8))
 453                return -EFAULT;
 454
 455        user_access_begin();
 456        while (nr_compat_longs > 1) {
 457                unsigned long m = *mask++;
 458                unsafe_put_user((compat_ulong_t)m, umask++, Efault);
 459                unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
 460                nr_compat_longs -= 2;
 461        }
 462        if (nr_compat_longs)
 463                unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
 464        user_access_end();
 465        return 0;
 466Efault:
 467        user_access_end();
 468        return -EFAULT;
 469}
 470
 471int
 472get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
 473{
 474#ifdef __BIG_ENDIAN
 475        compat_sigset_t v;
 476        if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
 477                return -EFAULT;
 478        switch (_NSIG_WORDS) {
 479        case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
 480        case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
 481        case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
 482        case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );
 483        }
 484#else
 485        if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
 486                return -EFAULT;
 487#endif
 488        return 0;
 489}
 490EXPORT_SYMBOL_GPL(get_compat_sigset);
 491
 492/*
 493 * Allocate user-space memory for the duration of a single system call,
 494 * in order to marshall parameters inside a compat thunk.
 495 */
 496void __user *compat_alloc_user_space(unsigned long len)
 497{
 498        void __user *ptr;
 499
 500        /* If len would occupy more than half of the entire compat space... */
 501        if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
 502                return NULL;
 503
 504        ptr = arch_compat_alloc_user_space(len);
 505
 506        if (unlikely(!access_ok(VERIFY_WRITE, ptr, len)))
 507                return NULL;
 508
 509        return ptr;
 510}
 511EXPORT_SYMBOL_GPL(compat_alloc_user_space);
 512