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 #include <asm/syscalls.h>
  14
  15 /*
  16  * The legacy ABI and the new ARM EABI have different rules making some
  17  * syscalls incompatible especially with structure arguments.
  18  * Most notably, Eabi says 64-bit members should be 64-bit aligned instead of
  19  * simply word aligned.  EABI also pads structures to the size of the largest
  20  * member it contains instead of the invariant 32-bit.
  21  *
  22  * The following syscalls are affected:
  23  *
  24  * sys_stat64:
  25  * sys_lstat64:
  26  * sys_fstat64:
  27  * sys_fstatat64:
  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/filelock.h>
  79 #include <linux/cred.h>
  80 #include <linux/fcntl.h>
  81 #include <linux/eventpoll.h>
  82 #include <linux/sem.h>
  83 #include <linux/socket.h>
  84 #include <linux/net.h>
  85 #include <linux/ipc.h>
  86 #include <linux/ipc_namespace.h>
  87 #include <linux/uaccess.h>
  88 #include <linux/slab.h>
  89
  90 #include <asm/syscall.h>
  91
  92 struct oldabi_stat64 {
  93         unsigned long long st_dev;
  94         unsigned int    __pad1;
  95         unsigned long   __st_ino;
  96         unsigned int    st_mode;
  97         unsigned int    st_nlink;
  98
  99         unsigned long   st_uid;
 100         unsigned long   st_gid;
 101
 102         unsigned long long st_rdev;
 103         unsigned int    __pad2;
 104
 105         long long       st_size;
 106         unsigned long   st_blksize;
 107         unsigned long long st_blocks;
 108
 109         unsigned long   st_atime;
 110         unsigned long   st_atime_nsec;
 111
 112         unsigned long   st_mtime;
 113         unsigned long   st_mtime_nsec;
 114
 115         unsigned long   st_ctime;
 116         unsigned long   st_ctime_nsec;
 117
 118         unsigned long long st_ino;
 119 } __attribute__ ((packed,aligned(4)));
 120
 121 static long cp_oldabi_stat64(struct kstat *stat,
 122                              struct oldabi_stat64 __user *statbuf)
 123 {
 124         struct oldabi_stat64 tmp;
 125
 126         tmp.st_dev = huge_encode_dev(stat->dev);
 127         tmp.__pad1 = 0;
 128         tmp.__st_ino = stat->ino;
 129         tmp.st_mode = stat->mode;
 130         tmp.st_nlink = stat->nlink;
 131         tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
 132         tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
 133         tmp.st_rdev = huge_encode_dev(stat->rdev);
 134         tmp.st_size = stat->size;
 135         tmp.st_blocks = stat->blocks;
 136         tmp.__pad2 = 0;
 137         tmp.st_blksize = stat->blksize;
 138         tmp.st_atime = stat->atime.tv_sec;
 139         tmp.st_atime_nsec = stat->atime.tv_nsec;
 140         tmp.st_mtime = stat->mtime.tv_sec;
 141         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 142         tmp.st_ctime = stat->ctime.tv_sec;
 143         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 144         tmp.st_ino = stat->ino;
 145         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 146 }
 147
 148 asmlinkage long sys_oabi_stat64(const char __user * filename,
 149                                 struct oldabi_stat64 __user * statbuf)
 150 {
 151         struct kstat stat;
 152         int error = vfs_stat(filename, &stat);
 153         if (!error)
 154                 error = cp_oldabi_stat64(&stat, statbuf);
 155         return error;
 156 }
 157
 158 asmlinkage long sys_oabi_lstat64(const char __user * filename,
 159                                  struct oldabi_stat64 __user * statbuf)
 160 {
 161         struct kstat stat;
 162         int error = vfs_lstat(filename, &stat);
 163         if (!error)
 164                 error = cp_oldabi_stat64(&stat, statbuf);
 165         return error;
 166 }
 167
 168 asmlinkage long sys_oabi_fstat64(unsigned long fd,
 169                                  struct oldabi_stat64 __user * statbuf)
 170 {
 171         struct kstat stat;
 172         int error = vfs_fstat(fd, &stat);
 173         if (!error)
 174                 error = cp_oldabi_stat64(&stat, statbuf);
 175         return error;
 176 }
 177
 178 asmlinkage long sys_oabi_fstatat64(int dfd,
 179                                    const char __user *filename,
 180                                    struct oldabi_stat64  __user *statbuf,
 181                                    int flag)
 182 {
 183         struct kstat stat;
 184         int error;
 185
 186         error = vfs_fstatat(dfd, filename, &stat, flag);
 187         if (error)
 188                 return error;
 189         return cp_oldabi_stat64(&stat, statbuf);
 190 }
 191
 192 struct oabi_flock64 {
 193         short   l_type;
 194         short   l_whence;
 195         loff_t  l_start;
 196         loff_t  l_len;
 197         pid_t   l_pid;
 198 } __attribute__ ((packed,aligned(4)));
 199
 200 static int get_oabi_flock(struct flock64 *kernel, struct oabi_flock64 __user *arg)
 201 {
 202         struct oabi_flock64 user;
 203
 204         if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
 205                            sizeof(user)))
 206                 return -EFAULT;
 207
 208         kernel->l_type   = user.l_type;
 209         kernel->l_whence = user.l_whence;
 210         kernel->l_start  = user.l_start;
 211         kernel->l_len    = user.l_len;
 212         kernel->l_pid    = user.l_pid;
 213
 214         return 0;
 215 }
 216
 217 static int put_oabi_flock(struct flock64 *kernel, struct oabi_flock64 __user *arg)
 218 {
 219         struct oabi_flock64 user;
 220
 221         user.l_type     = kernel->l_type;
 222         user.l_whence   = kernel->l_whence;
 223         user.l_start    = kernel->l_start;
 224         user.l_len      = kernel->l_len;
 225         user.l_pid      = kernel->l_pid;
 226
 227         if (copy_to_user((struct oabi_flock64 __user *)arg,
 228                          &user, sizeof(user)))
 229                 return -EFAULT;
 230
 231         return 0;
 232 }
 233
 234 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
 235                                  unsigned long arg)
 236 {
 237         void __user *argp = (void __user *)arg;
 238         CLASS(fd_raw, f)(fd);
 239         struct flock64 flock;
 240         long err;
 241
 242         if (fd_empty(f))
 243                 return -EBADF;
 244
 245         switch (cmd) {
 246         case F_GETLK64:
 247         case F_OFD_GETLK:
 248                 err = security_file_fcntl(fd_file(f), cmd, arg);
 249                 if (err)
 250                         break;
 251                 err = get_oabi_flock(&flock, argp);
 252                 if (err)
 253                         break;
 254                 err = fcntl_getlk64(fd_file(f), cmd, &flock);
 255                 if (!err)
 256                        err = put_oabi_flock(&flock, argp);
 257                 break;
 258         case F_SETLK64:
 259         case F_SETLKW64:
 260         case F_OFD_SETLK:
 261         case F_OFD_SETLKW:
 262                 err = security_file_fcntl(fd_file(f), cmd, arg);
 263                 if (err)
 264                         break;
 265                 err = get_oabi_flock(&flock, argp);
 266                 if (err)
 267                         break;
 268                 err = fcntl_setlk64(fd, fd_file(f), cmd, &flock);
 269                 break;
 270         default:
 271                 err = sys_fcntl64(fd, cmd, arg);
 272                 break;
 273         }
 274         return err;
 275 }
 276
 277 struct oabi_epoll_event {
 278         __poll_t events;
 279         __u64 data;
 280 } __attribute__ ((packed,aligned(4)));
 281
 282 #ifdef CONFIG_EPOLL
 283 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
 284                                    struct oabi_epoll_event __user *event)
 285 {
 286         struct oabi_epoll_event user;
 287         struct epoll_event kernel;
 288
 289         if (ep_op_has_event(op) &&
 290             copy_from_user(&user, event, sizeof(user)))
 291                 return -EFAULT;
 292
 293         kernel.events = user.events;
 294         kernel.data   = user.data;
 295
 296         return do_epoll_ctl(epfd, op, fd, &kernel, false);
 297 }
 298 #else
 299 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
 300                                    struct oabi_epoll_event __user *event)
 301 {
 302         return -EINVAL;
 303 }
 304 #endif
 305
 306 struct epoll_event __user *
 307 epoll_put_uevent(__poll_t revents, __u64 data,
 308                  struct epoll_event __user *uevent)
 309 {
 310         if (in_oabi_syscall()) {
 311                 struct oabi_epoll_event __user *oevent = (void __user *)uevent;
 312
 313                 if (__put_user(revents, &oevent->events) ||
 314                     __put_user(data, &oevent->data))
 315                         return NULL;
 316
 317                 return (void __user *)(oevent+1);
 318         }
 319
 320         if (__put_user(revents, &uevent->events) ||
 321             __put_user(data, &uevent->data))
 322                 return NULL;
 323
 324         return uevent+1;
 325 }
 326
 327 struct oabi_sembuf {
 328         unsigned short  sem_num;
 329         short           sem_op;
 330         short           sem_flg;
 331         unsigned short  __pad;
 332 };
 333
 334 #define sc_semopm     sem_ctls[2]
 335
 336 #ifdef CONFIG_SYSVIPC
 337 asmlinkage long sys_oabi_semtimedop(int semid,
 338                                     struct oabi_sembuf __user *tsops,
 339                                     unsigned nsops,
 340                                     const struct old_timespec32 __user *timeout)
 341 {
 342         struct ipc_namespace *ns;
 343         struct sembuf *sops;
 344         long err;
 345         int i;
 346
 347         ns = current->nsproxy->ipc_ns;
 348         if (nsops > ns->sc_semopm)
 349                 return -E2BIG;
 350         if (nsops < 1 || nsops > SEMOPM)
 351                 return -EINVAL;
 352         sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
 353         if (!sops)
 354                 return -ENOMEM;
 355         err = 0;
 356         for (i = 0; i < nsops; i++) {
 357                 struct oabi_sembuf osb;
 358                 err |= copy_from_user(&osb, tsops, sizeof(osb));
 359                 sops[i].sem_num = osb.sem_num;
 360                 sops[i].sem_op = osb.sem_op;
 361                 sops[i].sem_flg = osb.sem_flg;
 362                 tsops++;
 363         }
 364         if (err) {
 365                 err = -EFAULT;
 366                 goto out;
 367         }
 368
 369         if (timeout) {
 370                 struct timespec64 ts;
 371                 err = get_old_timespec32(&ts, timeout);
 372                 if (err)
 373                         goto out;
 374                 err = __do_semtimedop(semid, sops, nsops, &ts, ns);
 375                 goto out;
 376         }
 377         err = __do_semtimedop(semid, sops, nsops, NULL, ns);
 378 out:
 379         kvfree(sops);
 380         return err;
 381 }
 382
 383 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
 384                                unsigned nsops)
 385 {
 386         return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
 387 }
 388
 389 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
 390                             void __user *ptr, long fifth)
 391 {
 392         switch (call & 0xffff) {
 393         case SEMOP:
 394                 return  sys_oabi_semtimedop(first,
 395                                             (struct oabi_sembuf __user *)ptr,
 396                                             second, NULL);
 397         case SEMTIMEDOP:
 398                 return  sys_oabi_semtimedop(first,
 399                                             (struct oabi_sembuf __user *)ptr,
 400                                             second,
 401                                             (const struct old_timespec32 __user *)fifth);
 402         default:
 403                 return sys_ipc(call, first, second, third, ptr, fifth);
 404         }
 405 }
 406 #else
 407 asmlinkage long sys_oabi_semtimedop(int semid,
 408                                     struct oabi_sembuf __user *tsops,
 409                                     unsigned nsops,
 410                                     const struct old_timespec32 __user *timeout)
 411 {
 412         return -ENOSYS;
 413 }
 414
 415 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
 416                                unsigned nsops)
 417 {
 418         return -ENOSYS;
 419 }
 420
 421 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
 422                             void __user *ptr, long fifth)
 423 {
 424         return -ENOSYS;
 425 }
 426 #endif
 427
 428 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
 429 {
 430         sa_family_t sa_family;
 431         if (addrlen == 112 &&
 432             get_user(sa_family, &addr->sa_family) == 0 &&
 433             sa_family == AF_UNIX)
 434                         addrlen = 110;
 435         return sys_bind(fd, addr, addrlen);
 436 }
 437
 438 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
 439 {
 440         sa_family_t sa_family;
 441         if (addrlen == 112 &&
 442             get_user(sa_family, &addr->sa_family) == 0 &&
 443             sa_family == AF_UNIX)
 444                         addrlen = 110;
 445         return sys_connect(fd, addr, addrlen);
 446 }
 447
 448 asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
 449                                 size_t len, unsigned flags,
 450                                 struct sockaddr __user *addr,
 451                                 int addrlen)
 452 {
 453         sa_family_t sa_family;
 454         if (addrlen == 112 &&
 455             get_user(sa_family, &addr->sa_family) == 0 &&
 456             sa_family == AF_UNIX)
 457                         addrlen = 110;
 458         return sys_sendto(fd, buff, len, flags, addr, addrlen);
 459 }
 460
 461 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags)
 462 {
 463         struct sockaddr __user *addr;
 464         int msg_namelen;
 465         sa_family_t sa_family;
 466         if (msg &&
 467             get_user(msg_namelen, &msg->msg_namelen) == 0 &&
 468             msg_namelen == 112 &&
 469             get_user(addr, &msg->msg_name) == 0 &&
 470             get_user(sa_family, &addr->sa_family) == 0 &&
 471             sa_family == AF_UNIX)
 472         {
 473                 /*
 474                  * HACK ALERT: there is a limit to how much backward bending
 475                  * we should do for what is actually a transitional
 476                  * compatibility layer.  This already has known flaws with
 477                  * a few ioctls that we don't intend to fix.  Therefore
 478                  * consider this blatent hack as another one... and take care
 479                  * to run for cover.  In most cases it will "just work fine".
 480                  * If it doesn't, well, tough.
 481                  */
 482                 put_user(110, &msg->msg_namelen);
 483         }
 484         return sys_sendmsg(fd, msg, flags);
 485 }
 486
 487 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
 488 {
 489         unsigned long r = -EFAULT, a[6];
 490
 491         switch (call) {
 492         case SYS_BIND:
 493                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 494                         r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
 495                 break;
 496         case SYS_CONNECT:
 497                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 498                         r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
 499                 break;
 500         case SYS_SENDTO:
 501                 if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
 502                         r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
 503                                             (struct sockaddr __user *)a[4], a[5]);
 504                 break;
 505         case SYS_SENDMSG:
 506                 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
 507                         r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]);
 508                 break;
 509         default:
 510                 r = sys_socketcall(call, args);
 511         }
 512
 513         return r;
 514 }