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_GETLKP:
 207         case F_SETLKP:
 208         case F_SETLKPW:
 209         case F_GETLK64:
 210         case F_SETLK64:
 211         case F_SETLKW64:
 212                 if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
 213                                    sizeof(user)))
 214                         return -EFAULT;
 215                 kernel.l_type   = user.l_type;
 216                 kernel.l_whence = user.l_whence;
 217                 kernel.l_start  = user.l_start;
 218                 kernel.l_len    = user.l_len;
 219                 kernel.l_pid    = user.l_pid;
 220                 local_arg = (unsigned long)&kernel;
 221                 fs = get_fs();
 222                 set_fs(KERNEL_DS);
 223         }
 224
 225         ret = sys_fcntl64(fd, cmd, local_arg);
 226
 227         switch (cmd) {
 228         case F_GETLK64:
 229                 if (!ret) {
 230                         user.l_type     = kernel.l_type;
 231                         user.l_whence   = kernel.l_whence;
 232                         user.l_start    = kernel.l_start;
 233                         user.l_len      = kernel.l_len;
 234                         user.l_pid      = kernel.l_pid;
 235                         if (copy_to_user((struct oabi_flock64 __user *)arg,
 236                                          &user, sizeof(user)))
 237                                 ret = -EFAULT;
 238                 }
 239         case F_SETLK64:
 240         case F_SETLKW64:
 241                 set_fs(fs);
 242         }
 243
 244         return ret;
 245 }
 246
 247 struct oabi_epoll_event {
 248         __u32 events;
 249         __u64 data;
 250 } __attribute__ ((packed,aligned(4)));
 251
 252 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
 253                                    struct oabi_epoll_event __user *event)
 254 {
 255         struct oabi_epoll_event user;
 256         struct epoll_event kernel;
 257         mm_segment_t fs;
 258         long ret;
 259
 260         if (op == EPOLL_CTL_DEL)
 261                 return sys_epoll_ctl(epfd, op, fd, NULL);
 262         if (copy_from_user(&user, event, sizeof(user)))
 263                 return -EFAULT;
 264         kernel.events = user.events;
 265         kernel.data   = user.data;
 266         fs = get_fs();
 267         set_fs(KERNEL_DS);
 268         ret = sys_epoll_ctl(epfd, op, fd, &kernel);
 269         set_fs(fs);
 270         return ret;
 271 }
 272
 273 asmlinkage long sys_oabi_epoll_wait(int epfd,
 274                                     struct oabi_epoll_event __user *events,
 275                                     int maxevents, int timeout)
 276 {
 277         struct epoll_event *kbuf;
 278         mm_segment_t fs;
 279         long ret, err, i;
 280
 281         if (maxevents <= 0 || maxevents > (INT_MAX/sizeof(struct epoll_event)))
 282                 return -EINVAL;
 283         kbuf = kmalloc(sizeof(*kbuf) * maxevents, GFP_KERNEL);
 284         if (!kbuf)
 285                 return -ENOMEM;
 286         fs = get_fs();
 287         set_fs(KERNEL_DS);
 288         ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout);
 289         set_fs(fs);
 290         err = 0;
 291         for (i = 0; i < ret; i++) {
 292                 __put_user_error(kbuf[i].events, &events->events, err);
 293                 __put_user_error(kbuf[i].data,   &events->data,   err);
 294                 events++;
 295         }
 296         kfree(kbuf);
 297         return err ? -EFAULT : ret;
 298 }
 299
 300 struct oabi_sembuf {
 301         unsigned short  sem_num;
 302         short           sem_op;
 303         short           sem_flg;
 304         unsigned short  __pad;
 305 };
 306
 307 asmlinkage long sys_oabi_semtimedop(int semid,
 308                                     struct oabi_sembuf __user *tsops,
 309                                     unsigned nsops,
 310                                     const struct timespec __user *timeout)
 311 {
 312         struct sembuf *sops;
 313         struct timespec local_timeout;
 314         long err;
 315         int i;
 316
 317         if (nsops < 1 || nsops > SEMOPM)
 318                 return -EINVAL;
 319         sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL);
 320         if (!sops)
 321                 return -ENOMEM;
 322         err = 0;
 323         for (i = 0; i < nsops; i++) {
 324                 __get_user_error(sops[i].sem_num, &tsops->sem_num, err);
 325                 __get_user_error(sops[i].sem_op,  &tsops->sem_op,  err);
 326                 __get_user_error(sops[i].sem_flg, &tsops->sem_flg, err);
 327                 tsops++;
 328         }
 329         if (timeout) {
 330                 /* copy this as well before changing domain protection */
 331                 err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout));
 332                 timeout = &local_timeout;
 333         }
 334         if (err) {
 335                 err = -EFAULT;
 336         } else {
 337                 mm_segment_t fs = get_fs();
 338                 set_fs(KERNEL_DS);
 339                 err = sys_semtimedop(semid, sops, nsops, timeout);
 340                 set_fs(fs);
 341         }
 342         kfree(sops);
 343         return err;
 344 }
 345
 346 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
 347                                unsigned nsops)
 348 {
 349         return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
 350 }
 351
 352 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
 353                             void __user *ptr, long fifth)
 354 {
 355         switch (call & 0xffff) {
 356         case SEMOP:
 357                 return  sys_oabi_semtimedop(first,
 358                                             (struct oabi_sembuf __user *)ptr,
 359                                             second, NULL);
 360         case SEMTIMEDOP:
 361                 return  sys_oabi_semtimedop(first,
 362                                             (struct oabi_sembuf __user *)ptr,
 363                                             second,
 364                                             (const struct timespec __user *)fifth);
 365         default:
 366                 return sys_ipc(call, first, second, third, ptr, fifth);
 367         }
 368 }
 369
 370 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
 371 {
 372         sa_family_t sa_family;
 373         if (addrlen == 112 &&
 374             get_user(sa_family, &addr->sa_family) == 0 &&
 375             sa_family == AF_UNIX)
 376                         addrlen = 110;
 377         return sys_bind(fd, addr, addrlen);
 378 }
 379
 380 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
 381 {
 382         sa_family_t sa_family;
 383         if (addrlen == 112 &&
 384             get_user(sa_family, &addr->sa_family) == 0 &&
 385             sa_family == AF_UNIX)
 386                         addrlen = 110;
 387         return sys_connect(fd, addr, addrlen);
 388 }
 389
 390 asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
 391                                 size_t len, unsigned flags,
 392                                 struct sockaddr __user *addr,
 393                                 int addrlen)
 394 {
 395         sa_family_t sa_family;
 396         if (addrlen == 112 &&
 397             get_user(sa_family, &addr->sa_family) == 0 &&
 398             sa_family == AF_UNIX)
 399                         addrlen = 110;
 400         return sys_sendto(fd, buff, len, flags, addr, addrlen);
 401 }
 402
 403 asmlinkage long sys_oabi_sendmsg(int fd, struct msghdr __user *msg, unsigned flags)
 404 {
 405         struct sockaddr __user *addr;
 406         int msg_namelen;
 407         sa_family_t sa_family;
 408         if (msg &&
 409             get_user(msg_namelen, &msg->msg_namelen) == 0 &&
 410             msg_namelen == 112 &&
 411             get_user(addr, &msg->msg_name) == 0 &&
 412             get_user(sa_family, &addr->sa_family) == 0 &&
 413             sa_family == AF_UNIX)
 414         {
 415                 /*
 416                  * HACK ALERT: there is a limit to how much backward bending
 417                  * we should do for what is actually a transitional
 418                  * compatibility layer.  This already has known flaws with
 419                  * a few ioctls that we don't intend to fix.  Therefore
 420                  * consider this blatent hack as another one... and take care
 421                  * to run for cover.  In most cases it will "just work fine".
 422                  * If it doesn't, well, tough.
 423                  */
 424                 put_user(110, &msg->msg_namelen);
 425         }
 426         return sys_sendmsg(fd, msg, flags);
 427 }
 428
 429 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
 430 {
 431         unsigned long r = -EFAULT, a[6];
 432
 433         switch (call) {
 434         case SYS_BIND:
 435                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 436                         r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
 437                 break;
 438         case SYS_CONNECT:
 439                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 440                         r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
 441                 break;
 442         case SYS_SENDTO:
 443                 if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
 444                         r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
 445                                             (struct sockaddr __user *)a[4], a[5]);
 446                 break;
 447         case SYS_SENDMSG:
 448                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 449                         r = sys_oabi_sendmsg(a[0], (struct msghdr __user *)a[1], a[2]);
 450                 break;
 451         default:
 452                 r = sys_socketcall(call, args);
 453         }
 454
 455         return r;
 456 }