arch/arm/kernel/sys_oabi-compat.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  arch/arm/kernel/sys_oabi-compat.c
   4  *
   5  *  Compatibility wrappers for syscalls that are used from
   6  *  old ABI user space binaries with an EABI kernel.
   7  *
   8  *  Author:     Nicolas Pitre
   9  *  Created:    Oct 7, 2005
  10  *  Copyright:  MontaVista Software, Inc.
  11  */
  12
  13 /*
  14  * The legacy ABI and the new ARM EABI have different rules making some
  15  * syscalls incompatible especially with structure arguments.
  16  * Most notably, Eabi says 64-bit members should be 64-bit aligned instead of
  17  * simply word aligned.  EABI also pads structures to the size of the largest
  18  * member it contains instead of the invariant 32-bit.
  19  *
  20  * The following syscalls are affected:
  21  *
  22  * sys_stat64:
  23  * sys_lstat64:
  24  * sys_fstat64:
  25  * sys_fstatat64:
  26  *
  27  *   struct stat64 has different sizes and some members are shifted
  28  *   Compatibility wrappers are needed for them and provided below.
  29  *
  30  * sys_fcntl64:
  31  *
  32  *   struct flock64 has different sizes and some members are shifted
  33  *   A compatibility wrapper is needed and provided below.
  34  *
  35  * sys_statfs64:
  36  * sys_fstatfs64:
  37  *
  38  *   struct statfs64 has extra padding with EABI growing its size from
  39  *   84 to 88.  This struct is now __attribute__((packed,aligned(4)))
  40  *   with a small assembly wrapper to force the sz argument to 84 if it is 88
  41  *   to avoid copying the extra padding over user space unexpecting it.
  42  *
  43  * sys_newuname:
  44  *
  45  *   struct new_utsname has no padding with EABI.  No problem there.
  46  *
  47  * sys_epoll_ctl:
  48  * sys_epoll_wait:
  49  *
  50  *   struct epoll_event has its second member shifted also affecting the
  51  *   structure size. Compatibility wrappers are needed and provided below.
  52  *
  53  * sys_ipc:
  54  * sys_semop:
  55  * sys_semtimedop:
  56  *
  57  *   struct sembuf loses its padding with EABI.  Since arrays of them are
  58  *   used they have to be copyed to remove the padding. Compatibility wrappers
  59  *   provided below.
  60  *
  61  * sys_bind:
  62  * sys_connect:
  63  * sys_sendmsg:
  64  * sys_sendto:
  65  * sys_socketcall:
  66  *
  67  *   struct sockaddr_un loses its padding with EABI.  Since the size of the
  68  *   structure is used as a validation test in unix_mkname(), we need to
  69  *   change the length argument to 110 whenever it is 112.  Compatibility
  70  *   wrappers provided below.
  71  */
  72
  73 #include <linux/syscalls.h>
  74 #include <linux/errno.h>
  75 #include <linux/fs.h>
  76 #include <linux/cred.h>
  77 #include <linux/fcntl.h>
  78 #include <linux/eventpoll.h>
  79 #include <linux/sem.h>
  80 #include <linux/socket.h>
  81 #include <linux/net.h>
  82 #include <linux/ipc.h>
  83 #include <linux/uaccess.h>
  84 #include <linux/slab.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 = from_kuid_munged(current_user_ns(), stat->uid);
 126         tmp.st_gid = from_kgid_munged(current_user_ns(), 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(const 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(const 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 asmlinkage long sys_oabi_fstatat64(int dfd,
 173                                    const char __user *filename,
 174                                    struct oldabi_stat64  __user *statbuf,
 175                                    int flag)
 176 {
 177         struct kstat stat;
 178         int error;
 179
 180         error = vfs_fstatat(dfd, filename, &stat, flag);
 181         if (error)
 182                 return error;
 183         return cp_oldabi_stat64(&stat, statbuf);
 184 }
 185
 186 struct oabi_flock64 {
 187         short   l_type;
 188         short   l_whence;
 189         loff_t  l_start;
 190         loff_t  l_len;
 191         pid_t   l_pid;
 192 } __attribute__ ((packed,aligned(4)));
 193
 194 static long do_locks(unsigned int fd, unsigned int cmd,
 195                                  unsigned long arg)
 196 {
 197         struct flock64 kernel;
 198         struct oabi_flock64 user;
 199         mm_segment_t fs;
 200         long ret;
 201
 202         if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
 203                            sizeof(user)))
 204                 return -EFAULT;
 205         kernel.l_type   = user.l_type;
 206         kernel.l_whence = user.l_whence;
 207         kernel.l_start  = user.l_start;
 208         kernel.l_len    = user.l_len;
 209         kernel.l_pid    = user.l_pid;
 210
 211         fs = get_fs();
 212         set_fs(KERNEL_DS);
 213         ret = sys_fcntl64(fd, cmd, (unsigned long)&kernel);
 214         set_fs(fs);
 215
 216         if (!ret && (cmd == F_GETLK64 || cmd == F_OFD_GETLK)) {
 217                 user.l_type     = kernel.l_type;
 218                 user.l_whence   = kernel.l_whence;
 219                 user.l_start    = kernel.l_start;
 220                 user.l_len      = kernel.l_len;
 221                 user.l_pid      = kernel.l_pid;
 222                 if (copy_to_user((struct oabi_flock64 __user *)arg,
 223                                  &user, sizeof(user)))
 224                         ret = -EFAULT;
 225         }
 226         return ret;
 227 }
 228
 229 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
 230                                  unsigned long arg)
 231 {
 232         switch (cmd) {
 233         case F_OFD_GETLK:
 234         case F_OFD_SETLK:
 235         case F_OFD_SETLKW:
 236         case F_GETLK64:
 237         case F_SETLK64:
 238         case F_SETLKW64:
 239                 return do_locks(fd, cmd, arg);
 240
 241         default:
 242                 return sys_fcntl64(fd, cmd, arg);
 243         }
 244 }
 245
 246 struct oabi_epoll_event {
 247         __u32 events;
 248         __u64 data;
 249 } __attribute__ ((packed,aligned(4)));
 250
 251 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
 252                                    struct oabi_epoll_event __user *event)
 253 {
 254         struct oabi_epoll_event user;
 255         struct epoll_event kernel;
 256
 257         if (ep_op_has_event(op) &&
 258             copy_from_user(&user, event, sizeof(user)))
 259                 return -EFAULT;
 260
 261         kernel.events = user.events;
 262         kernel.data   = user.data;
 263
 264         return do_epoll_ctl(epfd, op, fd, &kernel, false);
 265 }
 266
 267 asmlinkage long sys_oabi_epoll_wait(int epfd,
 268                                     struct oabi_epoll_event __user *events,
 269                                     int maxevents, int timeout)
 270 {
 271         struct epoll_event *kbuf;
 272         struct oabi_epoll_event e;
 273         mm_segment_t fs;
 274         long ret, err, i;
 275
 276         if (maxevents <= 0 ||
 277                         maxevents > (INT_MAX/sizeof(*kbuf)) ||
 278                         maxevents > (INT_MAX/sizeof(*events)))
 279                 return -EINVAL;
 280         if (!access_ok(events, sizeof(*events) * maxevents))
 281                 return -EFAULT;
 282         kbuf = kmalloc_array(maxevents, sizeof(*kbuf), GFP_KERNEL);
 283         if (!kbuf)
 284                 return -ENOMEM;
 285         fs = get_fs();
 286         set_fs(KERNEL_DS);
 287         ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout);
 288         set_fs(fs);
 289         err = 0;
 290         for (i = 0; i < ret; i++) {
 291                 e.events = kbuf[i].events;
 292                 e.data = kbuf[i].data;
 293                 err = __copy_to_user(events, &e, sizeof(e));
 294                 if (err)
 295                         break;
 296                 events++;
 297         }
 298         kfree(kbuf);
 299         return err ? -EFAULT : ret;
 300 }
 301
 302 struct oabi_sembuf {
 303         unsigned short  sem_num;
 304         short           sem_op;
 305         short           sem_flg;
 306         unsigned short  __pad;
 307 };
 308
 309 asmlinkage long sys_oabi_semtimedop(int semid,
 310                                     struct oabi_sembuf __user *tsops,
 311                                     unsigned nsops,
 312                                     const struct old_timespec32 __user *timeout)
 313 {
 314         struct sembuf *sops;
 315         struct old_timespec32 local_timeout;
 316         long err;
 317         int i;
 318
 319         if (nsops < 1 || nsops > SEMOPM)
 320                 return -EINVAL;
 321         if (!access_ok(tsops, sizeof(*tsops) * nsops))
 322                 return -EFAULT;
 323         sops = kmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
 324         if (!sops)
 325                 return -ENOMEM;
 326         err = 0;
 327         for (i = 0; i < nsops; i++) {
 328                 struct oabi_sembuf osb;
 329                 err |= __copy_from_user(&osb, tsops, sizeof(osb));
 330                 sops[i].sem_num = osb.sem_num;
 331                 sops[i].sem_op = osb.sem_op;
 332                 sops[i].sem_flg = osb.sem_flg;
 333                 tsops++;
 334         }
 335         if (timeout) {
 336                 /* copy this as well before changing domain protection */
 337                 err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout));
 338                 timeout = &local_timeout;
 339         }
 340         if (err) {
 341                 err = -EFAULT;
 342         } else {
 343                 mm_segment_t fs = get_fs();
 344                 set_fs(KERNEL_DS);
 345                 err = sys_semtimedop_time32(semid, sops, nsops, timeout);
 346                 set_fs(fs);
 347         }
 348         kfree(sops);
 349         return err;
 350 }
 351
 352 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
 353                                unsigned nsops)
 354 {
 355         return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
 356 }
 357
 358 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
 359                             void __user *ptr, long fifth)
 360 {
 361         switch (call & 0xffff) {
 362         case SEMOP:
 363                 return  sys_oabi_semtimedop(first,
 364                                             (struct oabi_sembuf __user *)ptr,
 365                                             second, NULL);
 366         case SEMTIMEDOP:
 367                 return  sys_oabi_semtimedop(first,
 368                                             (struct oabi_sembuf __user *)ptr,
 369                                             second,
 370                                             (const struct old_timespec32 __user *)fifth);
 371         default:
 372                 return sys_ipc(call, first, second, third, ptr, fifth);
 373         }
 374 }
 375
 376 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
 377 {
 378         sa_family_t sa_family;
 379         if (addrlen == 112 &&
 380             get_user(sa_family, &addr->sa_family) == 0 &&
 381             sa_family == AF_UNIX)
 382                         addrlen = 110;
 383         return sys_bind(fd, addr, addrlen);
 384 }
 385
 386 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
 387 {
 388         sa_family_t sa_family;
 389         if (addrlen == 112 &&
 390             get_user(sa_family, &addr->sa_family) == 0 &&
 391             sa_family == AF_UNIX)
 392                         addrlen = 110;
 393         return sys_connect(fd, addr, addrlen);
 394 }
 395
 396 asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
 397                                 size_t len, unsigned flags,
 398                                 struct sockaddr __user *addr,
 399                                 int addrlen)
 400 {
 401         sa_family_t sa_family;
 402         if (addrlen == 112 &&
 403             get_user(sa_family, &addr->sa_family) == 0 &&
 404             sa_family == AF_UNIX)
 405                         addrlen = 110;
 406         return sys_sendto(fd, buff, len, flags, addr, addrlen);
 407 }
 408
 409 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags)
 410 {
 411         struct sockaddr __user *addr;
 412         int msg_namelen;
 413         sa_family_t sa_family;
 414         if (msg &&
 415             get_user(msg_namelen, &msg->msg_namelen) == 0 &&
 416             msg_namelen == 112 &&
 417             get_user(addr, &msg->msg_name) == 0 &&
 418             get_user(sa_family, &addr->sa_family) == 0 &&
 419             sa_family == AF_UNIX)
 420         {
 421                 /*
 422                  * HACK ALERT: there is a limit to how much backward bending
 423                  * we should do for what is actually a transitional
 424                  * compatibility layer.  This already has known flaws with
 425                  * a few ioctls that we don't intend to fix.  Therefore
 426                  * consider this blatent hack as another one... and take care
 427                  * to run for cover.  In most cases it will "just work fine".
 428                  * If it doesn't, well, tough.
 429                  */
 430                 put_user(110, &msg->msg_namelen);
 431         }
 432         return sys_sendmsg(fd, msg, flags);
 433 }
 434
 435 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
 436 {
 437         unsigned long r = -EFAULT, a[6];
 438
 439         switch (call) {
 440         case SYS_BIND:
 441                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 442                         r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
 443                 break;
 444         case SYS_CONNECT:
 445                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 446                         r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
 447                 break;
 448         case SYS_SENDTO:
 449                 if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
 450                         r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
 451                                             (struct sockaddr __user *)a[4], a[5]);
 452                 break;
 453         case SYS_SENDMSG:
 454                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 455                         r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]);
 456                 break;
 457         default:
 458                 r = sys_socketcall(call, args);
 459         }
 460
 461         return r;
 462 }