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