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