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
  29#ifdef __ARCH_WANT_SYS_SIGPROCMASK
  30
  31/*
  32 * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
  33 * blocked set of signals to the supplied signal set
  34 */
  35static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
  36{
  37        memcpy(blocked->sig, &set, sizeof(set));
  38}
  39
  40COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
  41                       compat_old_sigset_t __user *, nset,
  42                       compat_old_sigset_t __user *, oset)
  43{
  44        old_sigset_t old_set, new_set;
  45        sigset_t new_blocked;
  46
  47        old_set = current->blocked.sig[0];
  48
  49        if (nset) {
  50                if (get_user(new_set, nset))
  51                        return -EFAULT;
  52                new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
  53
  54                new_blocked = current->blocked;
  55
  56                switch (how) {
  57                case SIG_BLOCK:
  58                        sigaddsetmask(&new_blocked, new_set);
  59                        break;
  60                case SIG_UNBLOCK:
  61                        sigdelsetmask(&new_blocked, new_set);
  62                        break;
  63                case SIG_SETMASK:
  64                        compat_sig_setmask(&new_blocked, new_set);
  65                        break;
  66                default:
  67                        return -EINVAL;
  68                }
  69
  70                set_current_blocked(&new_blocked);
  71        }
  72
  73        if (oset) {
  74                if (put_user(old_set, oset))
  75                        return -EFAULT;
  76        }
  77
  78        return 0;
  79}
  80
  81#endif
  82
  83int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
  84{
  85        struct compat_rusage r32;
  86        memset(&r32, 0, sizeof(r32));
  87        r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
  88        r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
  89        r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
  90        r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
  91        r32.ru_maxrss = r->ru_maxrss;
  92        r32.ru_ixrss = r->ru_ixrss;
  93        r32.ru_idrss = r->ru_idrss;
  94        r32.ru_isrss = r->ru_isrss;
  95        r32.ru_minflt = r->ru_minflt;
  96        r32.ru_majflt = r->ru_majflt;
  97        r32.ru_nswap = r->ru_nswap;
  98        r32.ru_inblock = r->ru_inblock;
  99        r32.ru_oublock = r->ru_oublock;
 100        r32.ru_msgsnd = r->ru_msgsnd;
 101        r32.ru_msgrcv = r->ru_msgrcv;
 102        r32.ru_nsignals = r->ru_nsignals;
 103        r32.ru_nvcsw = r->ru_nvcsw;
 104        r32.ru_nivcsw = r->ru_nivcsw;
 105        if (copy_to_user(ru, &r32, sizeof(r32)))
 106                return -EFAULT;
 107        return 0;
 108}
 109
 110static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
 111                                    unsigned len, struct cpumask *new_mask)
 112{
 113        unsigned long *k;
 114
 115        if (len < cpumask_size())
 116                memset(new_mask, 0, cpumask_size());
 117        else if (len > cpumask_size())
 118                len = cpumask_size();
 119
 120        k = cpumask_bits(new_mask);
 121        return compat_get_bitmap(k, user_mask_ptr, len * 8);
 122}
 123
 124COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
 125                       unsigned int, len,
 126                       compat_ulong_t __user *, user_mask_ptr)
 127{
 128        cpumask_var_t new_mask;
 129        int retval;
 130
 131        if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
 132                return -ENOMEM;
 133
 134        retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
 135        if (retval)
 136                goto out;
 137
 138        retval = sched_setaffinity(pid, new_mask);
 139out:
 140        free_cpumask_var(new_mask);
 141        return retval;
 142}
 143
 144COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t,  pid, unsigned int, len,
 145                       compat_ulong_t __user *, user_mask_ptr)
 146{
 147        int ret;
 148        cpumask_var_t mask;
 149
 150        if ((len * BITS_PER_BYTE) < nr_cpu_ids)
 151                return -EINVAL;
 152        if (len & (sizeof(compat_ulong_t)-1))
 153                return -EINVAL;
 154
 155        if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
 156                return -ENOMEM;
 157
 158        ret = sched_getaffinity(pid, mask);
 159        if (ret == 0) {
 160                unsigned int retlen = min(len, cpumask_size());
 161
 162                if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
 163                        ret = -EFAULT;
 164                else
 165                        ret = retlen;
 166        }
 167        free_cpumask_var(mask);
 168
 169        return ret;
 170}
 171
 172/*
 173 * We currently only need the following fields from the sigevent
 174 * structure: sigev_value, sigev_signo, sig_notify and (sometimes
 175 * sigev_notify_thread_id).  The others are handled in user mode.
 176 * We also assume that copying sigev_value.sival_int is sufficient
 177 * to keep all the bits of sigev_value.sival_ptr intact.
 178 */
 179int get_compat_sigevent(struct sigevent *event,
 180                const struct compat_sigevent __user *u_event)
 181{
 182        memset(event, 0, sizeof(*event));
 183        return (!access_ok(u_event, sizeof(*u_event)) ||
 184                __get_user(event->sigev_value.sival_int,
 185                        &u_event->sigev_value.sival_int) ||
 186                __get_user(event->sigev_signo, &u_event->sigev_signo) ||
 187                __get_user(event->sigev_notify, &u_event->sigev_notify) ||
 188                __get_user(event->sigev_notify_thread_id,
 189                        &u_event->sigev_notify_thread_id))
 190                ? -EFAULT : 0;
 191}
 192
 193long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
 194                       unsigned long bitmap_size)
 195{
 196        unsigned long nr_compat_longs;
 197
 198        /* align bitmap up to nearest compat_long_t boundary */
 199        bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 200        nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
 201
 202        if (!user_read_access_begin(umask, bitmap_size / 8))
 203                return -EFAULT;
 204
 205        while (nr_compat_longs > 1) {
 206                compat_ulong_t l1, l2;
 207                unsafe_get_user(l1, umask++, Efault);
 208                unsafe_get_user(l2, umask++, Efault);
 209                *mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
 210                nr_compat_longs -= 2;
 211        }
 212        if (nr_compat_longs)
 213                unsafe_get_user(*mask, umask++, Efault);
 214        user_read_access_end();
 215        return 0;
 216
 217Efault:
 218        user_read_access_end();
 219        return -EFAULT;
 220}
 221
 222long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
 223                       unsigned long bitmap_size)
 224{
 225        unsigned long nr_compat_longs;
 226
 227        /* align bitmap up to nearest compat_long_t boundary */
 228        bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 229        nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
 230
 231        if (!user_write_access_begin(umask, bitmap_size / 8))
 232                return -EFAULT;
 233
 234        while (nr_compat_longs > 1) {
 235                unsigned long m = *mask++;
 236                unsafe_put_user((compat_ulong_t)m, umask++, Efault);
 237                unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
 238                nr_compat_longs -= 2;
 239        }
 240        if (nr_compat_longs)
 241                unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
 242        user_write_access_end();
 243        return 0;
 244Efault:
 245        user_write_access_end();
 246        return -EFAULT;
 247}
 248
 249int
 250get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
 251{
 252#ifdef __BIG_ENDIAN
 253        compat_sigset_t v;
 254        if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
 255                return -EFAULT;
 256        switch (_NSIG_WORDS) {
 257        case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
 258                fallthrough;
 259        case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
 260                fallthrough;
 261        case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
 262                fallthrough;
 263        case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );
 264        }
 265#else
 266        if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
 267                return -EFAULT;
 268#endif
 269        return 0;
 270}
 271EXPORT_SYMBOL_GPL(get_compat_sigset);
 272