linux/arch/arm/kernel/sys_oabi-compat.c
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   1/*
   2 *  arch/arm/kernel/sys_oabi-compat.c
   3 *
   4 *  Compatibility wrappers for syscalls that are used from
   5 *  old ABI user space binaries with an EABI kernel.
   6 *
   7 *  Author:     Nicolas Pitre
   8 *  Created:    Oct 7, 2005
   9 *  Copyright:  MontaVista Software, Inc.
  10 *
  11 *  This program is free software; you can redistribute it and/or modify
  12 *  it under the terms of the GNU General Public License version 2 as
  13 *  published by the Free Software Foundation.
  14 */
  15
  16/*
  17 * The legacy ABI and the new ARM EABI have different rules making some
  18 * syscalls incompatible especially with structure arguments.
  19 * Most notably, Eabi says 64-bit members should be 64-bit aligned instead of
  20 * simply word aligned.  EABI also pads structures to the size of the largest
  21 * member it contains instead of the invariant 32-bit.
  22 *
  23 * The following syscalls are affected:
  24 *
  25 * sys_stat64:
  26 * sys_lstat64:
  27 * sys_fstat64:
  28 * sys_fstatat64:
  29 *
  30 *   struct stat64 has different sizes and some members are shifted
  31 *   Compatibility wrappers are needed for them and provided below.
  32 *
  33 * sys_fcntl64:
  34 *
  35 *   struct flock64 has different sizes and some members are shifted
  36 *   A compatibility wrapper is needed and provided below.
  37 *
  38 * sys_statfs64:
  39 * sys_fstatfs64:
  40 *
  41 *   struct statfs64 has extra padding with EABI growing its size from
  42 *   84 to 88.  This struct is now __attribute__((packed,aligned(4)))
  43 *   with a small assembly wrapper to force the sz argument to 84 if it is 88
  44 *   to avoid copying the extra padding over user space unexpecting it.
  45 *
  46 * sys_newuname:
  47 *
  48 *   struct new_utsname has no padding with EABI.  No problem there.
  49 *
  50 * sys_epoll_ctl:
  51 * sys_epoll_wait:
  52 *
  53 *   struct epoll_event has its second member shifted also affecting the
  54 *   structure size. Compatibility wrappers are needed and provided below.
  55 *
  56 * sys_ipc:
  57 * sys_semop:
  58 * sys_semtimedop:
  59 *
  60 *   struct sembuf loses its padding with EABI.  Since arrays of them are
  61 *   used they have to be copyed to remove the padding. Compatibility wrappers
  62 *   provided below.
  63 *
  64 * sys_bind:
  65 * sys_connect:
  66 * sys_sendmsg:
  67 * sys_sendto:
  68 * sys_socketcall:
  69 *
  70 *   struct sockaddr_un loses its padding with EABI.  Since the size of the
  71 *   structure is used as a validation test in unix_mkname(), we need to
  72 *   change the length argument to 110 whenever it is 112.  Compatibility
  73 *   wrappers provided below.
  74 */
  75
  76#include <linux/syscalls.h>
  77#include <linux/errno.h>
  78#include <linux/fs.h>
  79#include <linux/fcntl.h>
  80#include <linux/eventpoll.h>
  81#include <linux/sem.h>
  82#include <linux/socket.h>
  83#include <linux/net.h>
  84#include <linux/ipc.h>
  85#include <linux/uaccess.h>
  86
  87struct oldabi_stat64 {
  88        unsigned long long st_dev;
  89        unsigned int    __pad1;
  90        unsigned long   __st_ino;
  91        unsigned int    st_mode;
  92        unsigned int    st_nlink;
  93
  94        unsigned long   st_uid;
  95        unsigned long   st_gid;
  96
  97        unsigned long long st_rdev;
  98        unsigned int    __pad2;
  99
 100        long long       st_size;
 101        unsigned long   st_blksize;
 102        unsigned long long st_blocks;
 103
 104        unsigned long   st_atime;
 105        unsigned long   st_atime_nsec;
 106
 107        unsigned long   st_mtime;
 108        unsigned long   st_mtime_nsec;
 109
 110        unsigned long   st_ctime;
 111        unsigned long   st_ctime_nsec;
 112
 113        unsigned long long st_ino;
 114} __attribute__ ((packed,aligned(4)));
 115
 116static long cp_oldabi_stat64(struct kstat *stat,
 117                             struct oldabi_stat64 __user *statbuf)
 118{
 119        struct oldabi_stat64 tmp;
 120
 121        tmp.st_dev = huge_encode_dev(stat->dev);
 122        tmp.__pad1 = 0;
 123        tmp.__st_ino = stat->ino;
 124        tmp.st_mode = stat->mode;
 125        tmp.st_nlink = stat->nlink;
 126        tmp.st_uid = stat->uid;
 127        tmp.st_gid = stat->gid;
 128        tmp.st_rdev = huge_encode_dev(stat->rdev);
 129        tmp.st_size = stat->size;
 130        tmp.st_blocks = stat->blocks;
 131        tmp.__pad2 = 0;
 132        tmp.st_blksize = stat->blksize;
 133        tmp.st_atime = stat->atime.tv_sec;
 134        tmp.st_atime_nsec = stat->atime.tv_nsec;
 135        tmp.st_mtime = stat->mtime.tv_sec;
 136        tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 137        tmp.st_ctime = stat->ctime.tv_sec;
 138        tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 139        tmp.st_ino = stat->ino;
 140        return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 141}
 142
 143asmlinkage long sys_oabi_stat64(char __user * filename,
 144                                struct oldabi_stat64 __user * statbuf)
 145{
 146        struct kstat stat;
 147        int error = vfs_stat(filename, &stat);
 148        if (!error)
 149                error = cp_oldabi_stat64(&stat, statbuf);
 150        return error;
 151}
 152
 153asmlinkage long sys_oabi_lstat64(char __user * filename,
 154                                 struct oldabi_stat64 __user * statbuf)
 155{
 156        struct kstat stat;
 157        int error = vfs_lstat(filename, &stat);
 158        if (!error)
 159                error = cp_oldabi_stat64(&stat, statbuf);
 160        return error;
 161}
 162
 163asmlinkage long sys_oabi_fstat64(unsigned long fd,
 164                                 struct oldabi_stat64 __user * statbuf)
 165{
 166        struct kstat stat;
 167        int error = vfs_fstat(fd, &stat);
 168        if (!error)
 169                error = cp_oldabi_stat64(&stat, statbuf);
 170        return error;
 171}
 172
 173asmlinkage long sys_oabi_fstatat64(int dfd,
 174                                   char __user *filename,
 175                                   struct oldabi_stat64  __user *statbuf,
 176                                   int flag)
 177{
 178        struct kstat stat;
 179        int error = -EINVAL;
 180
 181        if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
 182                goto out;
 183
 184        if (flag & AT_SYMLINK_NOFOLLOW)
 185                error = vfs_lstat_fd(dfd, filename, &stat);
 186        else
 187                error = vfs_stat_fd(dfd, filename, &stat);
 188
 189        if (!error)
 190        error = cp_oldabi_stat64(&stat, statbuf);
 191
 192out:
 193        return error;
 194}
 195
 196struct oabi_flock64 {
 197        short   l_type;
 198        short   l_whence;
 199        loff_t  l_start;
 200        loff_t  l_len;
 201        pid_t   l_pid;
 202} __attribute__ ((packed,aligned(4)));
 203
 204asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
 205                                 unsigned long arg)
 206{
 207        struct oabi_flock64 user;
 208        struct flock64 kernel;
 209        mm_segment_t fs = USER_DS; /* initialized to kill a warning */
 210        unsigned long local_arg = arg;
 211        int ret;
 212
 213        switch (cmd) {
 214        case F_GETLK64:
 215        case F_SETLK64:
 216        case F_SETLKW64:
 217                if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
 218                                   sizeof(user)))
 219                        return -EFAULT;
 220                kernel.l_type   = user.l_type;
 221                kernel.l_whence = user.l_whence;
 222                kernel.l_start  = user.l_start;
 223                kernel.l_len    = user.l_len;
 224                kernel.l_pid    = user.l_pid;
 225                local_arg = (unsigned long)&kernel;
 226                fs = get_fs();
 227                set_fs(KERNEL_DS);
 228        }
 229
 230        ret = sys_fcntl64(fd, cmd, local_arg);
 231
 232        switch (cmd) {
 233        case F_GETLK64:
 234                if (!ret) {
 235                        user.l_type     = kernel.l_type;
 236                        user.l_whence   = kernel.l_whence;
 237                        user.l_start    = kernel.l_start;
 238                        user.l_len      = kernel.l_len;
 239                        user.l_pid      = kernel.l_pid;
 240                        if (copy_to_user((struct oabi_flock64 __user *)arg,
 241                                         &user, sizeof(user)))
 242                                ret = -EFAULT;
 243                }
 244        case F_SETLK64:
 245        case F_SETLKW64:
 246                set_fs(fs);
 247        }
 248
 249        return ret;
 250}
 251
 252struct oabi_epoll_event {
 253        __u32 events;
 254        __u64 data;
 255} __attribute__ ((packed,aligned(4)));
 256
 257asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
 258                                   struct oabi_epoll_event __user *event)
 259{
 260        struct oabi_epoll_event user;
 261        struct epoll_event kernel;
 262        mm_segment_t fs;
 263        long ret;
 264
 265        if (op == EPOLL_CTL_DEL)
 266                return sys_epoll_ctl(epfd, op, fd, NULL);
 267        if (copy_from_user(&user, event, sizeof(user)))
 268                return -EFAULT;
 269        kernel.events = user.events;
 270        kernel.data   = user.data;
 271        fs = get_fs();
 272        set_fs(KERNEL_DS);
 273        ret = sys_epoll_ctl(epfd, op, fd, &kernel);
 274        set_fs(fs);
 275        return ret;
 276}
 277
 278asmlinkage long sys_oabi_epoll_wait(int epfd,
 279                                    struct oabi_epoll_event __user *events,
 280                                    int maxevents, int timeout)
 281{
 282        struct epoll_event *kbuf;
 283        mm_segment_t fs;
 284        long ret, err, i;
 285
 286        if (maxevents <= 0 || maxevents > (INT_MAX/sizeof(struct epoll_event)))
 287                return -EINVAL;
 288        kbuf = kmalloc(sizeof(*kbuf) * maxevents, GFP_KERNEL);
 289        if (!kbuf)
 290                return -ENOMEM;
 291        fs = get_fs();
 292        set_fs(KERNEL_DS);
 293        ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout);
 294        set_fs(fs);
 295        err = 0;
 296        for (i = 0; i < ret; i++) {
 297                __put_user_error(kbuf[i].events, &events->events, err);
 298                __put_user_error(kbuf[i].data,   &events->data,   err);
 299                events++;
 300        }
 301        kfree(kbuf);
 302        return err ? -EFAULT : ret;
 303}
 304
 305struct oabi_sembuf {
 306        unsigned short  sem_num;
 307        short           sem_op;
 308        short           sem_flg;
 309        unsigned short  __pad;
 310};
 311
 312asmlinkage long sys_oabi_semtimedop(int semid,
 313                                    struct oabi_sembuf __user *tsops,
 314                                    unsigned nsops,
 315                                    const struct timespec __user *timeout)
 316{
 317        struct sembuf *sops;
 318        struct timespec local_timeout;
 319        long err;
 320        int i;
 321
 322        if (nsops < 1)
 323                return -EINVAL;
 324        sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL);
 325        if (!sops)
 326                return -ENOMEM;
 327        err = 0;
 328        for (i = 0; i < nsops; i++) {
 329                __get_user_error(sops[i].sem_num, &tsops->sem_num, err);
 330                __get_user_error(sops[i].sem_op,  &tsops->sem_op,  err);
 331                __get_user_error(sops[i].sem_flg, &tsops->sem_flg, err);
 332                tsops++;
 333        }
 334        if (timeout) {
 335                /* copy this as well before changing domain protection */
 336                err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout));
 337                timeout = &local_timeout;
 338        }
 339        if (err) {
 340                err = -EFAULT;
 341        } else {
 342                mm_segment_t fs = get_fs();
 343                set_fs(KERNEL_DS);
 344                err = sys_semtimedop(semid, sops, nsops, timeout);
 345                set_fs(fs);
 346        }
 347        kfree(sops);
 348        return err;
 349}
 350
 351asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
 352                               unsigned nsops)
 353{
 354        return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
 355}
 356
 357extern asmlinkage int sys_ipc(uint call, int first, int second, int third,
 358                              void __user *ptr, long fifth);
 359
 360asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
 361                            void __user *ptr, long fifth)
 362{
 363        switch (call & 0xffff) {
 364        case SEMOP:
 365                return  sys_oabi_semtimedop(first,
 366                                            (struct oabi_sembuf __user *)ptr,
 367                                            second, NULL);
 368        case SEMTIMEDOP:
 369                return  sys_oabi_semtimedop(first,
 370                                            (struct oabi_sembuf __user *)ptr,
 371                                            second,
 372                                            (const struct timespec __user *)fifth);
 373        default:
 374                return sys_ipc(call, first, second, third, ptr, fifth);
 375        }
 376}
 377
 378asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
 379{
 380        sa_family_t sa_family;
 381        if (addrlen == 112 &&
 382            get_user(sa_family, &addr->sa_family) == 0 &&
 383            sa_family == AF_UNIX)
 384                        addrlen = 110;
 385        return sys_bind(fd, addr, addrlen);
 386}
 387
 388asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
 389{
 390        sa_family_t sa_family;
 391        if (addrlen == 112 &&
 392            get_user(sa_family, &addr->sa_family) == 0 &&
 393            sa_family == AF_UNIX)
 394                        addrlen = 110;
 395        return sys_connect(fd, addr, addrlen);
 396}
 397
 398asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
 399                                size_t len, unsigned flags,
 400                                struct sockaddr __user *addr,
 401                                int addrlen)
 402{
 403        sa_family_t sa_family;
 404        if (addrlen == 112 &&
 405            get_user(sa_family, &addr->sa_family) == 0 &&
 406            sa_family == AF_UNIX)
 407                        addrlen = 110;
 408        return sys_sendto(fd, buff, len, flags, addr, addrlen);
 409}
 410
 411asmlinkage long sys_oabi_sendmsg(int fd, struct msghdr __user *msg, unsigned flags)
 412{
 413        struct sockaddr __user *addr;
 414        int msg_namelen;
 415        sa_family_t sa_family;
 416        if (msg &&
 417            get_user(msg_namelen, &msg->msg_namelen) == 0 &&
 418            msg_namelen == 112 &&
 419            get_user(addr, &msg->msg_name) == 0 &&
 420            get_user(sa_family, &addr->sa_family) == 0 &&
 421            sa_family == AF_UNIX)
 422        {
 423                /*
 424                 * HACK ALERT: there is a limit to how much backward bending
 425                 * we should do for what is actually a transitional
 426                 * compatibility layer.  This already has known flaws with
 427                 * a few ioctls that we don't intend to fix.  Therefore
 428                 * consider this blatent hack as another one... and take care
 429                 * to run for cover.  In most cases it will "just work fine".
 430                 * If it doesn't, well, tough.
 431                 */
 432                put_user(110, &msg->msg_namelen);
 433        }
 434        return sys_sendmsg(fd, msg, flags);
 435}
 436
 437asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
 438{
 439        unsigned long r = -EFAULT, a[6];
 440
 441        switch (call) {
 442        case SYS_BIND:
 443                if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 444                        r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
 445                break;
 446        case SYS_CONNECT:
 447                if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 448                        r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
 449                break;
 450        case SYS_SENDTO:
 451                if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
 452                        r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
 453                                            (struct sockaddr __user *)a[4], a[5]);
 454                break;
 455        case SYS_SENDMSG:
 456                if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 457                        r = sys_oabi_sendmsg(a[0], (struct msghdr __user *)a[1], a[2]);
 458                break;
 459        default:
 460                r = sys_socketcall(call, args);
 461        }
 462
 463        return r;
 464}
 465
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