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 struct fd f = fdget_raw(fd); 239 struct flock64 flock; 240 long err = -EBADF; 241 242 if (!f.file) 243 goto out; 244 245 switch (cmd) { 246 case F_GETLK64: 247 case F_OFD_GETLK: 248 err = security_file_fcntl(f.file, cmd, arg); 249 if (err) 250 break; 251 err = get_oabi_flock(&flock, argp); 252 if (err) 253 break; 254 err = fcntl_getlk64(f.file, 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(f.file, cmd, arg); 263 if (err) 264 break; 265 err = get_oabi_flock(&flock, argp); 266 if (err) 267 break; 268 err = fcntl_setlk64(fd, f.file, cmd, &flock); 269 break; 270 default: 271 err = sys_fcntl64(fd, cmd, arg); 272 break; 273 } 274 fdput(f); 275 out: 276 return err; 277 } 278 279 struct oabi_epoll_event { 280 __poll_t events; 281 __u64 data; 282 } __attribute__ ((packed,aligned(4))); 283 284 #ifdef CONFIG_EPOLL 285 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd, 286 struct oabi_epoll_event __user *event) 287 { 288 struct oabi_epoll_event user; 289 struct epoll_event kernel; 290 291 if (ep_op_has_event(op) && 292 copy_from_user(&user, event, sizeof(user))) 293 return -EFAULT; 294 295 kernel.events = user.events; 296 kernel.data = user.data; 297 298 return do_epoll_ctl(epfd, op, fd, &kernel, false); 299 } 300 #else 301 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd, 302 struct oabi_epoll_event __user *event) 303 { 304 return -EINVAL; 305 } 306 #endif 307 308 struct epoll_event __user * 309 epoll_put_uevent(__poll_t revents, __u64 data, 310 struct epoll_event __user *uevent) 311 { 312 if (in_oabi_syscall()) { 313 struct oabi_epoll_event __user *oevent = (void __user *)uevent; 314 315 if (__put_user(revents, &oevent->events) || 316 __put_user(data, &oevent->data)) 317 return NULL; 318 319 return (void __user *)(oevent+1); 320 } 321 322 if (__put_user(revents, &uevent->events) || 323 __put_user(data, &uevent->data)) 324 return NULL; 325 326 return uevent+1; 327 } 328 329 struct oabi_sembuf { 330 unsigned short sem_num; 331 short sem_op; 332 short sem_flg; 333 unsigned short __pad; 334 }; 335 336 #define sc_semopm sem_ctls[2] 337 338 #ifdef CONFIG_SYSVIPC 339 asmlinkage long sys_oabi_semtimedop(int semid, 340 struct oabi_sembuf __user *tsops, 341 unsigned nsops, 342 const struct old_timespec32 __user *timeout) 343 { 344 struct ipc_namespace *ns; 345 struct sembuf *sops; 346 long err; 347 int i; 348 349 ns = current->nsproxy->ipc_ns; 350 if (nsops > ns->sc_semopm) 351 return -E2BIG; 352 if (nsops < 1 || nsops > SEMOPM) 353 return -EINVAL; 354 sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL); 355 if (!sops) 356 return -ENOMEM; 357 err = 0; 358 for (i = 0; i < nsops; i++) { 359 struct oabi_sembuf osb; 360 err |= copy_from_user(&osb, tsops, sizeof(osb)); 361 sops[i].sem_num = osb.sem_num; 362 sops[i].sem_op = osb.sem_op; 363 sops[i].sem_flg = osb.sem_flg; 364 tsops++; 365 } 366 if (err) { 367 err = -EFAULT; 368 goto out; 369 } 370 371 if (timeout) { 372 struct timespec64 ts; 373 err = get_old_timespec32(&ts, timeout); 374 if (err) 375 goto out; 376 err = __do_semtimedop(semid, sops, nsops, &ts, ns); 377 goto out; 378 } 379 err = __do_semtimedop(semid, sops, nsops, NULL, ns); 380 out: 381 kvfree(sops); 382 return err; 383 } 384 385 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops, 386 unsigned nsops) 387 { 388 return sys_oabi_semtimedop(semid, tsops, nsops, NULL); 389 } 390 391 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third, 392 void __user *ptr, long fifth) 393 { 394 switch (call & 0xffff) { 395 case SEMOP: 396 return sys_oabi_semtimedop(first, 397 (struct oabi_sembuf __user *)ptr, 398 second, NULL); 399 case SEMTIMEDOP: 400 return sys_oabi_semtimedop(first, 401 (struct oabi_sembuf __user *)ptr, 402 second, 403 (const struct old_timespec32 __user *)fifth); 404 default: 405 return sys_ipc(call, first, second, third, ptr, fifth); 406 } 407 } 408 #else 409 asmlinkage long sys_oabi_semtimedop(int semid, 410 struct oabi_sembuf __user *tsops, 411 unsigned nsops, 412 const struct old_timespec32 __user *timeout) 413 { 414 return -ENOSYS; 415 } 416 417 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops, 418 unsigned nsops) 419 { 420 return -ENOSYS; 421 } 422 423 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third, 424 void __user *ptr, long fifth) 425 { 426 return -ENOSYS; 427 } 428 #endif 429 430 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen) 431 { 432 sa_family_t sa_family; 433 if (addrlen == 112 && 434 get_user(sa_family, &addr->sa_family) == 0 && 435 sa_family == AF_UNIX) 436 addrlen = 110; 437 return sys_bind(fd, addr, addrlen); 438 } 439 440 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen) 441 { 442 sa_family_t sa_family; 443 if (addrlen == 112 && 444 get_user(sa_family, &addr->sa_family) == 0 && 445 sa_family == AF_UNIX) 446 addrlen = 110; 447 return sys_connect(fd, addr, addrlen); 448 } 449 450 asmlinkage long sys_oabi_sendto(int fd, void __user *buff, 451 size_t len, unsigned flags, 452 struct sockaddr __user *addr, 453 int addrlen) 454 { 455 sa_family_t sa_family; 456 if (addrlen == 112 && 457 get_user(sa_family, &addr->sa_family) == 0 && 458 sa_family == AF_UNIX) 459 addrlen = 110; 460 return sys_sendto(fd, buff, len, flags, addr, addrlen); 461 } 462 463 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags) 464 { 465 struct sockaddr __user *addr; 466 int msg_namelen; 467 sa_family_t sa_family; 468 if (msg && 469 get_user(msg_namelen, &msg->msg_namelen) == 0 && 470 msg_namelen == 112 && 471 get_user(addr, &msg->msg_name) == 0 && 472 get_user(sa_family, &addr->sa_family) == 0 && 473 sa_family == AF_UNIX) 474 { 475 /* 476 * HACK ALERT: there is a limit to how much backward bending 477 * we should do for what is actually a transitional 478 * compatibility layer. This already has known flaws with 479 * a few ioctls that we don't intend to fix. Therefore 480 * consider this blatent hack as another one... and take care 481 * to run for cover. In most cases it will "just work fine". 482 * If it doesn't, well, tough. 483 */ 484 put_user(110, &msg->msg_namelen); 485 } 486 return sys_sendmsg(fd, msg, flags); 487 } 488 489 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args) 490 { 491 unsigned long r = -EFAULT, a[6]; 492 493 switch (call) { 494 case SYS_BIND: 495 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 496 r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]); 497 break; 498 case SYS_CONNECT: 499 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 500 r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]); 501 break; 502 case SYS_SENDTO: 503 if (copy_from_user(a, args, 6 * sizeof(long)) == 0) 504 r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3], 505 (struct sockaddr __user *)a[4], a[5]); 506 break; 507 case SYS_SENDMSG: 508 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 509 r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]); 510 break; 511 default: 512 r = sys_socketcall(call, args); 513 } 514 515 return r; 516 } 517