arch/arm/kernel/sys_oabi-compat.c

   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 <asm/uaccess.h>
  86
  87 struct 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
 116 static 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
 143 asmlinkage 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
 153 asmlinkage 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
 163 asmlinkage 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
 173 asmlinkage 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
 192 out:
 193         return error;
 194 }
 195
 196 struct 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
 204 asmlinkage 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
 252 struct oabi_epoll_event {
 253         __u32 events;
 254         __u64 data;
 255 } __attribute__ ((packed,aligned(4)));
 256
 257 asmlinkage 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
 278 asmlinkage 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
 305 struct oabi_sembuf {
 306         unsigned short  sem_num;
 307         short           sem_op;
 308         short           sem_flg;
 309         unsigned short  __pad;
 310 };
 311
 312 asmlinkage 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
 351 asmlinkage 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
 357 extern asmlinkage int sys_ipc(uint call, int first, int second, int third,
 358                               void __user *ptr, long fifth);
 359
 360 asmlinkage 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
 378 asmlinkage 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
 388 asmlinkage 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
 398 asmlinkage 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
 411 asmlinkage 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
 437 asmlinkage 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 }