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/filelock.h> 77 #include <linux/cred.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 <linux/ipc_namespace.h> 85 #include <linux/uaccess.h> 86 #include <linux/slab.h> 87 88 #include <asm/syscall.h> 89 90 struct oldabi_stat64 { 91 unsigned long long st_dev; 92 unsigned int __pad1; 93 unsigned long __st_ino; 94 unsigned int st_mode; 95 unsigned int st_nlink; 96 97 unsigned long st_uid; 98 unsigned long st_gid; 99 100 unsigned long long st_rdev; 101 unsigned int __pad2; 102 103 long long st_size; 104 unsigned long st_blksize; 105 unsigned long long st_blocks; 106 107 unsigned long st_atime; 108 unsigned long st_atime_nsec; 109 110 unsigned long st_mtime; 111 unsigned long st_mtime_nsec; 112 113 unsigned long st_ctime; 114 unsigned long st_ctime_nsec; 115 116 unsigned long long st_ino; 117 } __attribute__ ((packed,aligned(4))); 118 119 static long cp_oldabi_stat64(struct kstat *stat, 120 struct oldabi_stat64 __user *statbuf) 121 { 122 struct oldabi_stat64 tmp; 123 124 tmp.st_dev = huge_encode_dev(stat->dev); 125 tmp.__pad1 = 0; 126 tmp.__st_ino = stat->ino; 127 tmp.st_mode = stat->mode; 128 tmp.st_nlink = stat->nlink; 129 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid); 130 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid); 131 tmp.st_rdev = huge_encode_dev(stat->rdev); 132 tmp.st_size = stat->size; 133 tmp.st_blocks = stat->blocks; 134 tmp.__pad2 = 0; 135 tmp.st_blksize = stat->blksize; 136 tmp.st_atime = stat->atime.tv_sec; 137 tmp.st_atime_nsec = stat->atime.tv_nsec; 138 tmp.st_mtime = stat->mtime.tv_sec; 139 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 140 tmp.st_ctime = stat->ctime.tv_sec; 141 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 142 tmp.st_ino = stat->ino; 143 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 144 } 145 146 asmlinkage long sys_oabi_stat64(const char __user * filename, 147 struct oldabi_stat64 __user * statbuf) 148 { 149 struct kstat stat; 150 int error = vfs_stat(filename, &stat); 151 if (!error) 152 error = cp_oldabi_stat64(&stat, statbuf); 153 return error; 154 } 155 156 asmlinkage long sys_oabi_lstat64(const char __user * filename, 157 struct oldabi_stat64 __user * statbuf) 158 { 159 struct kstat stat; 160 int error = vfs_lstat(filename, &stat); 161 if (!error) 162 error = cp_oldabi_stat64(&stat, statbuf); 163 return error; 164 } 165 166 asmlinkage long sys_oabi_fstat64(unsigned long fd, 167 struct oldabi_stat64 __user * statbuf) 168 { 169 struct kstat stat; 170 int error = vfs_fstat(fd, &stat); 171 if (!error) 172 error = cp_oldabi_stat64(&stat, statbuf); 173 return error; 174 } 175 176 asmlinkage long sys_oabi_fstatat64(int dfd, 177 const char __user *filename, 178 struct oldabi_stat64 __user *statbuf, 179 int flag) 180 { 181 struct kstat stat; 182 int error; 183 184 error = vfs_fstatat(dfd, filename, &stat, flag); 185 if (error) 186 return error; 187 return cp_oldabi_stat64(&stat, statbuf); 188 } 189 190 struct oabi_flock64 { 191 short l_type; 192 short l_whence; 193 loff_t l_start; 194 loff_t l_len; 195 pid_t l_pid; 196 } __attribute__ ((packed,aligned(4))); 197 198 static int get_oabi_flock(struct flock64 *kernel, struct oabi_flock64 __user *arg) 199 { 200 struct oabi_flock64 user; 201 202 if (copy_from_user(&user, (struct oabi_flock64 __user *)arg, 203 sizeof(user))) 204 return -EFAULT; 205 206 kernel->l_type = user.l_type; 207 kernel->l_whence = user.l_whence; 208 kernel->l_start = user.l_start; 209 kernel->l_len = user.l_len; 210 kernel->l_pid = user.l_pid; 211 212 return 0; 213 } 214 215 static int put_oabi_flock(struct flock64 *kernel, struct oabi_flock64 __user *arg) 216 { 217 struct oabi_flock64 user; 218 219 user.l_type = kernel->l_type; 220 user.l_whence = kernel->l_whence; 221 user.l_start = kernel->l_start; 222 user.l_len = kernel->l_len; 223 user.l_pid = kernel->l_pid; 224 225 if (copy_to_user((struct oabi_flock64 __user *)arg, 226 &user, sizeof(user))) 227 return -EFAULT; 228 229 return 0; 230 } 231 232 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd, 233 unsigned long arg) 234 { 235 void __user *argp = (void __user *)arg; 236 struct fd f = fdget_raw(fd); 237 struct flock64 flock; 238 long err = -EBADF; 239 240 if (!f.file) 241 goto out; 242 243 switch (cmd) { 244 case F_GETLK64: 245 case F_OFD_GETLK: 246 err = security_file_fcntl(f.file, cmd, arg); 247 if (err) 248 break; 249 err = get_oabi_flock(&flock, argp); 250 if (err) 251 break; 252 err = fcntl_getlk64(f.file, cmd, &flock); 253 if (!err) 254 err = put_oabi_flock(&flock, argp); 255 break; 256 case F_SETLK64: 257 case F_SETLKW64: 258 case F_OFD_SETLK: 259 case F_OFD_SETLKW: 260 err = security_file_fcntl(f.file, cmd, arg); 261 if (err) 262 break; 263 err = get_oabi_flock(&flock, argp); 264 if (err) 265 break; 266 err = fcntl_setlk64(fd, f.file, cmd, &flock); 267 break; 268 default: 269 err = sys_fcntl64(fd, cmd, arg); 270 break; 271 } 272 fdput(f); 273 out: 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 } 515