linux/kernel/compat.c
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   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
 124int compat_get_timeval(struct timeval *tv, const void __user *utv)
 125{
 126        if (COMPAT_USE_64BIT_TIME)
 127                return copy_from_user(tv, utv, sizeof(*tv)) ? -EFAULT : 0;
 128        else
 129                return __compat_get_timeval(tv, utv);
 130}
 131EXPORT_SYMBOL_GPL(compat_get_timeval);
 132
 133int compat_put_timeval(const struct timeval *tv, void __user *utv)
 134{
 135        if (COMPAT_USE_64BIT_TIME)
 136                return copy_to_user(utv, tv, sizeof(*tv)) ? -EFAULT : 0;
 137        else
 138                return __compat_put_timeval(tv, utv);
 139}
 140EXPORT_SYMBOL_GPL(compat_put_timeval);
 141
 142int compat_get_timespec(struct timespec *ts, const void __user *uts)
 143{
 144        if (COMPAT_USE_64BIT_TIME)
 145                return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
 146        else
 147                return __compat_get_timespec(ts, uts);
 148}
 149EXPORT_SYMBOL_GPL(compat_get_timespec);
 150
 151int compat_put_timespec(const struct timespec *ts, void __user *uts)
 152{
 153        if (COMPAT_USE_64BIT_TIME)
 154                return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
 155        else
 156                return __compat_put_timespec(ts, uts);
 157}
 158EXPORT_SYMBOL_GPL(compat_put_timespec);
 159
 160int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i)
 161{
 162        struct compat_itimerval v32;
 163
 164        if (copy_from_user(&v32, i, sizeof(struct compat_itimerval)))
 165                return -EFAULT;
 166        o->it_interval.tv_sec = v32.it_interval.tv_sec;
 167        o->it_interval.tv_usec = v32.it_interval.tv_usec;
 168        o->it_value.tv_sec = v32.it_value.tv_sec;
 169        o->it_value.tv_usec = v32.it_value.tv_usec;
 170        return 0;
 171}
 172
 173int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)
 174{
 175        struct compat_itimerval v32;
 176
 177        v32.it_interval.tv_sec = i->it_interval.tv_sec;
 178        v32.it_interval.tv_usec = i->it_interval.tv_usec;
 179        v32.it_value.tv_sec = i->it_value.tv_sec;
 180        v32.it_value.tv_usec = i->it_value.tv_usec;
 181        return copy_to_user(o, &v32, sizeof(struct compat_itimerval)) ? -EFAULT : 0;
 182}
 183
 184#ifdef __ARCH_WANT_SYS_SIGPROCMASK
 185
 186/*
 187 * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
 188 * blocked set of signals to the supplied signal set
 189 */
 190static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
 191{
 192        memcpy(blocked->sig, &set, sizeof(set));
 193}
 194
 195COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
 196                       compat_old_sigset_t __user *, nset,
 197                       compat_old_sigset_t __user *, oset)
 198{
 199        old_sigset_t old_set, new_set;
 200        sigset_t new_blocked;
 201
 202        old_set = current->blocked.sig[0];
 203
 204        if (nset) {
 205                if (get_user(new_set, nset))
 206                        return -EFAULT;
 207                new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
 208
 209                new_blocked = current->blocked;
 210
 211                switch (how) {
 212                case SIG_BLOCK:
 213                        sigaddsetmask(&new_blocked, new_set);
 214                        break;
 215                case SIG_UNBLOCK:
 216                        sigdelsetmask(&new_blocked, new_set);
 217                        break;
 218                case SIG_SETMASK:
 219                        compat_sig_setmask(&new_blocked, new_set);
 220                        break;
 221                default:
 222                        return -EINVAL;
 223                }
 224
 225                set_current_blocked(&new_blocked);
 226        }
 227
 228        if (oset) {
 229                if (put_user(old_set, oset))
 230                        return -EFAULT;
 231        }
 232
 233        return 0;
 234}
 235
 236#endif
 237
 238int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
 239{
 240        struct compat_rusage r32;
 241        memset(&r32, 0, sizeof(r32));
 242        r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
 243        r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
 244        r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
 245        r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
 246        r32.ru_maxrss = r->ru_maxrss;
 247        r32.ru_ixrss = r->ru_ixrss;
 248        r32.ru_idrss = r->ru_idrss;
 249        r32.ru_isrss = r->ru_isrss;
 250        r32.ru_minflt = r->ru_minflt;
 251        r32.ru_majflt = r->ru_majflt;
 252        r32.ru_nswap = r->ru_nswap;
 253        r32.ru_inblock = r->ru_inblock;
 254        r32.ru_oublock = r->ru_oublock;
 255        r32.ru_msgsnd = r->ru_msgsnd;
 256        r32.ru_msgrcv = r->ru_msgrcv;
 257        r32.ru_nsignals = r->ru_nsignals;
 258        r32.ru_nvcsw = r->ru_nvcsw;
 259        r32.ru_nivcsw = r->ru_nivcsw;
 260        if (copy_to_user(ru, &r32, sizeof(r32)))
 261                return -EFAULT;
 262        return 0;
 263}
 264
 265static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
 266                                    unsigned len, struct cpumask *new_mask)
 267{
 268        unsigned long *k;
 269
 270        if (len < cpumask_size())
 271                memset(new_mask, 0, cpumask_size());
 272        else if (len > cpumask_size())
 273                len = cpumask_size();
 274
 275        k = cpumask_bits(new_mask);
 276        return compat_get_bitmap(k, user_mask_ptr, len * 8);
 277}
 278
 279COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
 280                       unsigned int, len,
 281                       compat_ulong_t __user *, user_mask_ptr)
 282{
 283        cpumask_var_t new_mask;
 284        int retval;
 285
 286        if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
 287                return -ENOMEM;
 288
 289        retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
 290        if (retval)
 291                goto out;
 292
 293        retval = sched_setaffinity(pid, new_mask);
 294out:
 295        free_cpumask_var(new_mask);
 296        return retval;
 297}
 298
 299COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t,  pid, unsigned int, len,
 300                       compat_ulong_t __user *, user_mask_ptr)
 301{
 302        int ret;
 303        cpumask_var_t mask;
 304
 305        if ((len * BITS_PER_BYTE) < nr_cpu_ids)
 306                return -EINVAL;
 307        if (len & (sizeof(compat_ulong_t)-1))
 308                return -EINVAL;
 309
 310        if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 311                return -ENOMEM;
 312
 313        ret = sched_getaffinity(pid, mask);
 314        if (ret == 0) {
 315                unsigned int retlen = min(len, cpumask_size());
 316
 317                if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
 318                        ret = -EFAULT;
 319                else
 320                        ret = retlen;
 321        }
 322        free_cpumask_var(mask);
 323
 324        return ret;
 325}
 326
 327/*
 328 * We currently only need the following fields from the sigevent
 329 * structure: sigev_value, sigev_signo, sig_notify and (sometimes
 330 * sigev_notify_thread_id).  The others are handled in user mode.
 331 * We also assume that copying sigev_value.sival_int is sufficient
 332 * to keep all the bits of sigev_value.sival_ptr intact.
 333 */
 334int get_compat_sigevent(struct sigevent *event,
 335                const struct compat_sigevent __user *u_event)
 336{
 337        memset(event, 0, sizeof(*event));
 338        return (!access_ok(VERIFY_READ, u_event, sizeof(*u_event)) ||
 339                __get_user(event->sigev_value.sival_int,
 340                        &u_event->sigev_value.sival_int) ||
 341                __get_user(event->sigev_signo, &u_event->sigev_signo) ||
 342                __get_user(event->sigev_notify, &u_event->sigev_notify) ||
 343                __get_user(event->sigev_notify_thread_id,
 344                        &u_event->sigev_notify_thread_id))
 345                ? -EFAULT : 0;
 346}
 347
 348long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
 349                       unsigned long bitmap_size)
 350{
 351        unsigned long nr_compat_longs;
 352
 353        /* align bitmap up to nearest compat_long_t boundary */
 354        bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 355        nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
 356
 357        if (!access_ok(VERIFY_READ, umask, bitmap_size / 8))
 358                return -EFAULT;
 359
 360        user_access_begin();
 361        while (nr_compat_longs > 1) {
 362                compat_ulong_t l1, l2;
 363                unsafe_get_user(l1, umask++, Efault);
 364                unsafe_get_user(l2, umask++, Efault);
 365                *mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
 366                nr_compat_longs -= 2;
 367        }
 368        if (nr_compat_longs)
 369                unsafe_get_user(*mask, umask++, Efault);
 370        user_access_end();
 371        return 0;
 372
 373Efault:
 374        user_access_end();
 375        return -EFAULT;
 376}
 377
 378long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
 379                       unsigned long bitmap_size)
 380{
 381        unsigned long nr_compat_longs;
 382
 383        /* align bitmap up to nearest compat_long_t boundary */
 384        bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 385        nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
 386
 387        if (!access_ok(VERIFY_WRITE, umask, bitmap_size / 8))
 388                return -EFAULT;
 389
 390        user_access_begin();
 391        while (nr_compat_longs > 1) {
 392                unsigned long m = *mask++;
 393                unsafe_put_user((compat_ulong_t)m, umask++, Efault);
 394                unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
 395                nr_compat_longs -= 2;
 396        }
 397        if (nr_compat_longs)
 398                unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
 399        user_access_end();
 400        return 0;
 401Efault:
 402        user_access_end();
 403        return -EFAULT;
 404}
 405
 406int
 407get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
 408{
 409#ifdef __BIG_ENDIAN
 410        compat_sigset_t v;
 411        if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
 412                return -EFAULT;
 413        switch (_NSIG_WORDS) {
 414        case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
 415        case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
 416        case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
 417        case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );
 418        }
 419#else
 420        if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
 421                return -EFAULT;
 422#endif
 423        return 0;
 424}
 425EXPORT_SYMBOL_GPL(get_compat_sigset);
 426
 427/*
 428 * Allocate user-space memory for the duration of a single system call,
 429 * in order to marshall parameters inside a compat thunk.
 430 */
 431void __user *compat_alloc_user_space(unsigned long len)
 432{
 433        void __user *ptr;
 434
 435        /* If len would occupy more than half of the entire compat space... */
 436        if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
 437                return NULL;
 438
 439        ptr = arch_compat_alloc_user_space(len);
 440
 441        if (unlikely(!access_ok(VERIFY_WRITE, ptr, len)))
 442                return NULL;
 443
 444        return ptr;
 445}
 446EXPORT_SYMBOL_GPL(compat_alloc_user_space);
 447