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 <linux/uaccess.h>
  86 #include <linux/slab.h>
  87
  88 struct oldabi_stat64 {
  89         unsigned long long st_dev;
  90         unsigned int    __pad1;
  91         unsigned long   __st_ino;
  92         unsigned int    st_mode;
  93         unsigned int    st_nlink;
  94
  95         unsigned long   st_uid;
  96         unsigned long   st_gid;
  97
  98         unsigned long long st_rdev;
  99         unsigned int    __pad2;
 100
 101         long long       st_size;
 102         unsigned long   st_blksize;
 103         unsigned long long st_blocks;
 104
 105         unsigned long   st_atime;
 106         unsigned long   st_atime_nsec;
 107
 108         unsigned long   st_mtime;
 109         unsigned long   st_mtime_nsec;
 110
 111         unsigned long   st_ctime;
 112         unsigned long   st_ctime_nsec;
 113
 114         unsigned long long st_ino;
 115 } __attribute__ ((packed,aligned(4)));
 116
 117 static long cp_oldabi_stat64(struct kstat *stat,
 118                              struct oldabi_stat64 __user *statbuf)
 119 {
 120         struct oldabi_stat64 tmp;
 121
 122         tmp.st_dev = huge_encode_dev(stat->dev);
 123         tmp.__pad1 = 0;
 124         tmp.__st_ino = stat->ino;
 125         tmp.st_mode = stat->mode;
 126         tmp.st_nlink = stat->nlink;
 127         tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
 128         tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
 129         tmp.st_rdev = huge_encode_dev(stat->rdev);
 130         tmp.st_size = stat->size;
 131         tmp.st_blocks = stat->blocks;
 132         tmp.__pad2 = 0;
 133         tmp.st_blksize = stat->blksize;
 134         tmp.st_atime = stat->atime.tv_sec;
 135         tmp.st_atime_nsec = stat->atime.tv_nsec;
 136         tmp.st_mtime = stat->mtime.tv_sec;
 137         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 138         tmp.st_ctime = stat->ctime.tv_sec;
 139         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 140         tmp.st_ino = stat->ino;
 141         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 142 }
 143
 144 asmlinkage long sys_oabi_stat64(const char __user * filename,
 145                                 struct oldabi_stat64 __user * statbuf)
 146 {
 147         struct kstat stat;
 148         int error = vfs_stat(filename, &stat);
 149         if (!error)
 150                 error = cp_oldabi_stat64(&stat, statbuf);
 151         return error;
 152 }
 153
 154 asmlinkage long sys_oabi_lstat64(const char __user * filename,
 155                                  struct oldabi_stat64 __user * statbuf)
 156 {
 157         struct kstat stat;
 158         int error = vfs_lstat(filename, &stat);
 159         if (!error)
 160                 error = cp_oldabi_stat64(&stat, statbuf);
 161         return error;
 162 }
 163
 164 asmlinkage long sys_oabi_fstat64(unsigned long fd,
 165                                  struct oldabi_stat64 __user * statbuf)
 166 {
 167         struct kstat stat;
 168         int error = vfs_fstat(fd, &stat);
 169         if (!error)
 170                 error = cp_oldabi_stat64(&stat, statbuf);
 171         return error;
 172 }
 173
 174 asmlinkage long sys_oabi_fstatat64(int dfd,
 175                                    const char __user *filename,
 176                                    struct oldabi_stat64  __user *statbuf,
 177                                    int flag)
 178 {
 179         struct kstat stat;
 180         int error;
 181
 182         error = vfs_fstatat(dfd, filename, &stat, flag);
 183         if (error)
 184                 return error;
 185         return cp_oldabi_stat64(&stat, statbuf);
 186 }
 187
 188 struct oabi_flock64 {
 189         short   l_type;
 190         short   l_whence;
 191         loff_t  l_start;
 192         loff_t  l_len;
 193         pid_t   l_pid;
 194 } __attribute__ ((packed,aligned(4)));
 195
 196 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
 197                                  unsigned long arg)
 198 {
 199         struct oabi_flock64 user;
 200         struct flock64 kernel;
 201         mm_segment_t fs = USER_DS; /* initialized to kill a warning */
 202         unsigned long local_arg = arg;
 203         int ret;
 204
 205         switch (cmd) {
 206         case F_GETLK64:
 207         case F_SETLK64:
 208         case F_SETLKW64:
 209                 if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
 210                                    sizeof(user)))
 211                         return -EFAULT;
 212                 kernel.l_type   = user.l_type;
 213                 kernel.l_whence = user.l_whence;
 214                 kernel.l_start  = user.l_start;
 215                 kernel.l_len    = user.l_len;
 216                 kernel.l_pid    = user.l_pid;
 217                 local_arg = (unsigned long)&kernel;
 218                 fs = get_fs();
 219                 set_fs(KERNEL_DS);
 220         }
 221
 222         ret = sys_fcntl64(fd, cmd, local_arg);
 223
 224         switch (cmd) {
 225         case F_GETLK64:
 226                 if (!ret) {
 227                         user.l_type     = kernel.l_type;
 228                         user.l_whence   = kernel.l_whence;
 229                         user.l_start    = kernel.l_start;
 230                         user.l_len      = kernel.l_len;
 231                         user.l_pid      = kernel.l_pid;
 232                         if (copy_to_user((struct oabi_flock64 __user *)arg,
 233                                          &user, sizeof(user)))
 234                                 ret = -EFAULT;
 235                 }
 236         case F_SETLK64:
 237         case F_SETLKW64:
 238                 set_fs(fs);
 239         }
 240
 241         return ret;
 242 }
 243
 244 struct oabi_epoll_event {
 245         __u32 events;
 246         __u64 data;
 247 } __attribute__ ((packed,aligned(4)));
 248
 249 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
 250                                    struct oabi_epoll_event __user *event)
 251 {
 252         struct oabi_epoll_event user;
 253         struct epoll_event kernel;
 254         mm_segment_t fs;
 255         long ret;
 256
 257         if (op == EPOLL_CTL_DEL)
 258                 return sys_epoll_ctl(epfd, op, fd, NULL);
 259         if (copy_from_user(&user, event, sizeof(user)))
 260                 return -EFAULT;
 261         kernel.events = user.events;
 262         kernel.data   = user.data;
 263         fs = get_fs();
 264         set_fs(KERNEL_DS);
 265         ret = sys_epoll_ctl(epfd, op, fd, &kernel);
 266         set_fs(fs);
 267         return ret;
 268 }
 269
 270 asmlinkage long sys_oabi_epoll_wait(int epfd,
 271                                     struct oabi_epoll_event __user *events,
 272                                     int maxevents, int timeout)
 273 {
 274         struct epoll_event *kbuf;
 275         mm_segment_t fs;
 276         long ret, err, i;
 277
 278         if (maxevents <= 0 || maxevents > (INT_MAX/sizeof(struct epoll_event)))
 279                 return -EINVAL;
 280         kbuf = kmalloc(sizeof(*kbuf) * maxevents, GFP_KERNEL);
 281         if (!kbuf)
 282                 return -ENOMEM;
 283         fs = get_fs();
 284         set_fs(KERNEL_DS);
 285         ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout);
 286         set_fs(fs);
 287         err = 0;
 288         for (i = 0; i < ret; i++) {
 289                 __put_user_error(kbuf[i].events, &events->events, err);
 290                 __put_user_error(kbuf[i].data,   &events->data,   err);
 291                 events++;
 292         }
 293         kfree(kbuf);
 294         return err ? -EFAULT : ret;
 295 }
 296
 297 struct oabi_sembuf {
 298         unsigned short  sem_num;
 299         short           sem_op;
 300         short           sem_flg;
 301         unsigned short  __pad;
 302 };
 303
 304 asmlinkage long sys_oabi_semtimedop(int semid,
 305                                     struct oabi_sembuf __user *tsops,
 306                                     unsigned nsops,
 307                                     const struct timespec __user *timeout)
 308 {
 309         struct sembuf *sops;
 310         struct timespec local_timeout;
 311         long err;
 312         int i;
 313
 314         if (nsops < 1 || nsops > SEMOPM)
 315                 return -EINVAL;
 316         sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL);
 317         if (!sops)
 318                 return -ENOMEM;
 319         err = 0;
 320         for (i = 0; i < nsops; i++) {
 321                 __get_user_error(sops[i].sem_num, &tsops->sem_num, err);
 322                 __get_user_error(sops[i].sem_op,  &tsops->sem_op,  err);
 323                 __get_user_error(sops[i].sem_flg, &tsops->sem_flg, err);
 324                 tsops++;
 325         }
 326         if (timeout) {
 327                 /* copy this as well before changing domain protection */
 328                 err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout));
 329                 timeout = &local_timeout;
 330         }
 331         if (err) {
 332                 err = -EFAULT;
 333         } else {
 334                 mm_segment_t fs = get_fs();
 335                 set_fs(KERNEL_DS);
 336                 err = sys_semtimedop(semid, sops, nsops, timeout);
 337                 set_fs(fs);
 338         }
 339         kfree(sops);
 340         return err;
 341 }
 342
 343 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
 344                                unsigned nsops)
 345 {
 346         return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
 347 }
 348
 349 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
 350                             void __user *ptr, long fifth)
 351 {
 352         switch (call & 0xffff) {
 353         case SEMOP:
 354                 return  sys_oabi_semtimedop(first,
 355                                             (struct oabi_sembuf __user *)ptr,
 356                                             second, NULL);
 357         case SEMTIMEDOP:
 358                 return  sys_oabi_semtimedop(first,
 359                                             (struct oabi_sembuf __user *)ptr,
 360                                             second,
 361                                             (const struct timespec __user *)fifth);
 362         default:
 363                 return sys_ipc(call, first, second, third, ptr, fifth);
 364         }
 365 }
 366
 367 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
 368 {
 369         sa_family_t sa_family;
 370         if (addrlen == 112 &&
 371             get_user(sa_family, &addr->sa_family) == 0 &&
 372             sa_family == AF_UNIX)
 373                         addrlen = 110;
 374         return sys_bind(fd, addr, addrlen);
 375 }
 376
 377 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
 378 {
 379         sa_family_t sa_family;
 380         if (addrlen == 112 &&
 381             get_user(sa_family, &addr->sa_family) == 0 &&
 382             sa_family == AF_UNIX)
 383                         addrlen = 110;
 384         return sys_connect(fd, addr, addrlen);
 385 }
 386
 387 asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
 388                                 size_t len, unsigned flags,
 389                                 struct sockaddr __user *addr,
 390                                 int addrlen)
 391 {
 392         sa_family_t sa_family;
 393         if (addrlen == 112 &&
 394             get_user(sa_family, &addr->sa_family) == 0 &&
 395             sa_family == AF_UNIX)
 396                         addrlen = 110;
 397         return sys_sendto(fd, buff, len, flags, addr, addrlen);
 398 }
 399
 400 asmlinkage long sys_oabi_sendmsg(int fd, struct msghdr __user *msg, unsigned flags)
 401 {
 402         struct sockaddr __user *addr;
 403         int msg_namelen;
 404         sa_family_t sa_family;
 405         if (msg &&
 406             get_user(msg_namelen, &msg->msg_namelen) == 0 &&
 407             msg_namelen == 112 &&
 408             get_user(addr, &msg->msg_name) == 0 &&
 409             get_user(sa_family, &addr->sa_family) == 0 &&
 410             sa_family == AF_UNIX)
 411         {
 412                 /*
 413                  * HACK ALERT: there is a limit to how much backward bending
 414                  * we should do for what is actually a transitional
 415                  * compatibility layer.  This already has known flaws with
 416                  * a few ioctls that we don't intend to fix.  Therefore
 417                  * consider this blatent hack as another one... and take care
 418                  * to run for cover.  In most cases it will "just work fine".
 419                  * If it doesn't, well, tough.
 420                  */
 421                 put_user(110, &msg->msg_namelen);
 422         }
 423         return sys_sendmsg(fd, msg, flags);
 424 }
 425
 426 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
 427 {
 428         unsigned long r = -EFAULT, a[6];
 429
 430         switch (call) {
 431         case SYS_BIND:
 432                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 433                         r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
 434                 break;
 435         case SYS_CONNECT:
 436                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 437                         r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
 438                 break;
 439         case SYS_SENDTO:
 440                 if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
 441                         r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
 442                                             (struct sockaddr __user *)a[4], a[5]);
 443                 break;
 444         case SYS_SENDMSG:
 445                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 446                         r = sys_oabi_sendmsg(a[0], (struct msghdr __user *)a[1], a[2]);
 447                 break;
 448         default:
 449                 r = sys_socketcall(call, args);
 450         }
 451
 452         return r;
 453 }