1 /* 2 * arch/arm/kernel/sys_oabi-compat.c 3 * 4 * Compatibility wrappers for syscalls that are used from 5 * old ABI user space binaries with an EABI kernel. 6 * 7 * Author: Nicolas Pitre 8 * Created: Oct 7, 2005 9 * Copyright: MontaVista Software, Inc. 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * published by the Free Software Foundation. 14 */ 15 16 /* 17 * The legacy ABI and the new ARM EABI have different rules making some 18 * syscalls incompatible especially with structure arguments. 19 * Most notably, Eabi says 64-bit members should be 64-bit aligned instead of 20 * simply word aligned. EABI also pads structures to the size of the largest 21 * member it contains instead of the invariant 32-bit. 22 * 23 * The following syscalls are affected: 24 * 25 * sys_stat64: 26 * sys_lstat64: 27 * sys_fstat64: 28 * sys_fstatat64: 29 * 30 * struct stat64 has different sizes and some members are shifted 31 * Compatibility wrappers are needed for them and provided below. 32 * 33 * sys_fcntl64: 34 * 35 * struct flock64 has different sizes and some members are shifted 36 * A compatibility wrapper is needed and provided below. 37 * 38 * sys_statfs64: 39 * sys_fstatfs64: 40 * 41 * struct statfs64 has extra padding with EABI growing its size from 42 * 84 to 88. This struct is now __attribute__((packed,aligned(4))) 43 * with a small assembly wrapper to force the sz argument to 84 if it is 88 44 * to avoid copying the extra padding over user space unexpecting it. 45 * 46 * sys_newuname: 47 * 48 * struct new_utsname has no padding with EABI. No problem there. 49 * 50 * sys_epoll_ctl: 51 * sys_epoll_wait: 52 * 53 * struct epoll_event has its second member shifted also affecting the 54 * structure size. Compatibility wrappers are needed and provided below. 55 * 56 * sys_ipc: 57 * sys_semop: 58 * sys_semtimedop: 59 * 60 * struct sembuf loses its padding with EABI. Since arrays of them are 61 * used they have to be copyed to remove the padding. Compatibility wrappers 62 * provided below. 63 * 64 * sys_bind: 65 * sys_connect: 66 * sys_sendmsg: 67 * sys_sendto: 68 * sys_socketcall: 69 * 70 * struct sockaddr_un loses its padding with EABI. Since the size of the 71 * structure is used as a validation test in unix_mkname(), we need to 72 * change the length argument to 110 whenever it is 112. Compatibility 73 * wrappers provided below. 74 */ 75 76 #include <linux/syscalls.h> 77 #include <linux/errno.h> 78 #include <linux/fs.h> 79 #include <linux/fcntl.h> 80 #include <linux/eventpoll.h> 81 #include <linux/sem.h> 82 #include <linux/socket.h> 83 #include <linux/net.h> 84 #include <linux/ipc.h> 85 #include <asm/uaccess.h> 86 87 struct oldabi_stat64 { 88 unsigned long long st_dev; 89 unsigned int __pad1; 90 unsigned long __st_ino; 91 unsigned int st_mode; 92 unsigned int st_nlink; 93 94 unsigned long st_uid; 95 unsigned long st_gid; 96 97 unsigned long long st_rdev; 98 unsigned int __pad2; 99 100 long long st_size; 101 unsigned long st_blksize; 102 unsigned long long st_blocks; 103 104 unsigned long st_atime; 105 unsigned long st_atime_nsec; 106 107 unsigned long st_mtime; 108 unsigned long st_mtime_nsec; 109 110 unsigned long st_ctime; 111 unsigned long st_ctime_nsec; 112 113 unsigned long long st_ino; 114 } __attribute__ ((packed,aligned(4))); 115 116 static long cp_oldabi_stat64(struct kstat *stat, 117 struct oldabi_stat64 __user *statbuf) 118 { 119 struct oldabi_stat64 tmp; 120 121 tmp.st_dev = huge_encode_dev(stat->dev); 122 tmp.__pad1 = 0; 123 tmp.__st_ino = stat->ino; 124 tmp.st_mode = stat->mode; 125 tmp.st_nlink = stat->nlink; 126 tmp.st_uid = stat->uid; 127 tmp.st_gid = stat->gid; 128 tmp.st_rdev = huge_encode_dev(stat->rdev); 129 tmp.st_size = stat->size; 130 tmp.st_blocks = stat->blocks; 131 tmp.__pad2 = 0; 132 tmp.st_blksize = stat->blksize; 133 tmp.st_atime = stat->atime.tv_sec; 134 tmp.st_atime_nsec = stat->atime.tv_nsec; 135 tmp.st_mtime = stat->mtime.tv_sec; 136 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 137 tmp.st_ctime = stat->ctime.tv_sec; 138 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 139 tmp.st_ino = stat->ino; 140 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 141 } 142 143 asmlinkage long sys_oabi_stat64(char __user * filename, 144 struct oldabi_stat64 __user * statbuf) 145 { 146 struct kstat stat; 147 int error = vfs_stat(filename, &stat); 148 if (!error) 149 error = cp_oldabi_stat64(&stat, statbuf); 150 return error; 151 } 152 153 asmlinkage long sys_oabi_lstat64(char __user * filename, 154 struct oldabi_stat64 __user * statbuf) 155 { 156 struct kstat stat; 157 int error = vfs_lstat(filename, &stat); 158 if (!error) 159 error = cp_oldabi_stat64(&stat, statbuf); 160 return error; 161 } 162 163 asmlinkage long sys_oabi_fstat64(unsigned long fd, 164 struct oldabi_stat64 __user * statbuf) 165 { 166 struct kstat stat; 167 int error = vfs_fstat(fd, &stat); 168 if (!error) 169 error = cp_oldabi_stat64(&stat, statbuf); 170 return error; 171 } 172 173 asmlinkage long sys_oabi_fstatat64(int dfd, 174 char __user *filename, 175 struct oldabi_stat64 __user *statbuf, 176 int flag) 177 { 178 struct kstat stat; 179 int error = -EINVAL; 180 181 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) 182 goto out; 183 184 if (flag & AT_SYMLINK_NOFOLLOW) 185 error = vfs_lstat_fd(dfd, filename, &stat); 186 else 187 error = vfs_stat_fd(dfd, filename, &stat); 188 189 if (!error) 190 error = cp_oldabi_stat64(&stat, statbuf); 191 192 out: 193 return error; 194 } 195 196 struct oabi_flock64 { 197 short l_type; 198 short l_whence; 199 loff_t l_start; 200 loff_t l_len; 201 pid_t l_pid; 202 } __attribute__ ((packed,aligned(4))); 203 204 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd, 205 unsigned long arg) 206 { 207 struct oabi_flock64 user; 208 struct flock64 kernel; 209 mm_segment_t fs = USER_DS; /* initialized to kill a warning */ 210 unsigned long local_arg = arg; 211 int ret; 212 213 switch (cmd) { 214 case F_GETLK64: 215 case F_SETLK64: 216 case F_SETLKW64: 217 if (copy_from_user(&user, (struct oabi_flock64 __user *)arg, 218 sizeof(user))) 219 return -EFAULT; 220 kernel.l_type = user.l_type; 221 kernel.l_whence = user.l_whence; 222 kernel.l_start = user.l_start; 223 kernel.l_len = user.l_len; 224 kernel.l_pid = user.l_pid; 225 local_arg = (unsigned long)&kernel; 226 fs = get_fs(); 227 set_fs(KERNEL_DS); 228 } 229 230 ret = sys_fcntl64(fd, cmd, local_arg); 231 232 switch (cmd) { 233 case F_GETLK64: 234 if (!ret) { 235 user.l_type = kernel.l_type; 236 user.l_whence = kernel.l_whence; 237 user.l_start = kernel.l_start; 238 user.l_len = kernel.l_len; 239 user.l_pid = kernel.l_pid; 240 if (copy_to_user((struct oabi_flock64 __user *)arg, 241 &user, sizeof(user))) 242 ret = -EFAULT; 243 } 244 case F_SETLK64: 245 case F_SETLKW64: 246 set_fs(fs); 247 } 248 249 return ret; 250 } 251 252 struct oabi_epoll_event { 253 __u32 events; 254 __u64 data; 255 } __attribute__ ((packed,aligned(4))); 256 257 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd, 258 struct oabi_epoll_event __user *event) 259 { 260 struct oabi_epoll_event user; 261 struct epoll_event kernel; 262 mm_segment_t fs; 263 long ret; 264 265 if (op == EPOLL_CTL_DEL) 266 return sys_epoll_ctl(epfd, op, fd, NULL); 267 if (copy_from_user(&user, event, sizeof(user))) 268 return -EFAULT; 269 kernel.events = user.events; 270 kernel.data = user.data; 271 fs = get_fs(); 272 set_fs(KERNEL_DS); 273 ret = sys_epoll_ctl(epfd, op, fd, &kernel); 274 set_fs(fs); 275 return ret; 276 } 277 278 asmlinkage long sys_oabi_epoll_wait(int epfd, 279 struct oabi_epoll_event __user *events, 280 int maxevents, int timeout) 281 { 282 struct epoll_event *kbuf; 283 mm_segment_t fs; 284 long ret, err, i; 285 286 if (maxevents <= 0 || maxevents > (INT_MAX/sizeof(struct epoll_event))) 287 return -EINVAL; 288 kbuf = kmalloc(sizeof(*kbuf) * maxevents, GFP_KERNEL); 289 if (!kbuf) 290 return -ENOMEM; 291 fs = get_fs(); 292 set_fs(KERNEL_DS); 293 ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout); 294 set_fs(fs); 295 err = 0; 296 for (i = 0; i < ret; i++) { 297 __put_user_error(kbuf[i].events, &events->events, err); 298 __put_user_error(kbuf[i].data, &events->data, err); 299 events++; 300 } 301 kfree(kbuf); 302 return err ? -EFAULT : ret; 303 } 304 305 struct oabi_sembuf { 306 unsigned short sem_num; 307 short sem_op; 308 short sem_flg; 309 unsigned short __pad; 310 }; 311 312 asmlinkage long sys_oabi_semtimedop(int semid, 313 struct oabi_sembuf __user *tsops, 314 unsigned nsops, 315 const struct timespec __user *timeout) 316 { 317 struct sembuf *sops; 318 struct timespec local_timeout; 319 long err; 320 int i; 321 322 if (nsops < 1) 323 return -EINVAL; 324 sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL); 325 if (!sops) 326 return -ENOMEM; 327 err = 0; 328 for (i = 0; i < nsops; i++) { 329 __get_user_error(sops[i].sem_num, &tsops->sem_num, err); 330 __get_user_error(sops[i].sem_op, &tsops->sem_op, err); 331 __get_user_error(sops[i].sem_flg, &tsops->sem_flg, err); 332 tsops++; 333 } 334 if (timeout) { 335 /* copy this as well before changing domain protection */ 336 err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout)); 337 timeout = &local_timeout; 338 } 339 if (err) { 340 err = -EFAULT; 341 } else { 342 mm_segment_t fs = get_fs(); 343 set_fs(KERNEL_DS); 344 err = sys_semtimedop(semid, sops, nsops, timeout); 345 set_fs(fs); 346 } 347 kfree(sops); 348 return err; 349 } 350 351 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops, 352 unsigned nsops) 353 { 354 return sys_oabi_semtimedop(semid, tsops, nsops, NULL); 355 } 356 357 extern asmlinkage int sys_ipc(uint call, int first, int second, int third, 358 void __user *ptr, long fifth); 359 360 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third, 361 void __user *ptr, long fifth) 362 { 363 switch (call & 0xffff) { 364 case SEMOP: 365 return sys_oabi_semtimedop(first, 366 (struct oabi_sembuf __user *)ptr, 367 second, NULL); 368 case SEMTIMEDOP: 369 return sys_oabi_semtimedop(first, 370 (struct oabi_sembuf __user *)ptr, 371 second, 372 (const struct timespec __user *)fifth); 373 default: 374 return sys_ipc(call, first, second, third, ptr, fifth); 375 } 376 } 377 378 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen) 379 { 380 sa_family_t sa_family; 381 if (addrlen == 112 && 382 get_user(sa_family, &addr->sa_family) == 0 && 383 sa_family == AF_UNIX) 384 addrlen = 110; 385 return sys_bind(fd, addr, addrlen); 386 } 387 388 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen) 389 { 390 sa_family_t sa_family; 391 if (addrlen == 112 && 392 get_user(sa_family, &addr->sa_family) == 0 && 393 sa_family == AF_UNIX) 394 addrlen = 110; 395 return sys_connect(fd, addr, addrlen); 396 } 397 398 asmlinkage long sys_oabi_sendto(int fd, void __user *buff, 399 size_t len, unsigned flags, 400 struct sockaddr __user *addr, 401 int addrlen) 402 { 403 sa_family_t sa_family; 404 if (addrlen == 112 && 405 get_user(sa_family, &addr->sa_family) == 0 && 406 sa_family == AF_UNIX) 407 addrlen = 110; 408 return sys_sendto(fd, buff, len, flags, addr, addrlen); 409 } 410 411 asmlinkage long sys_oabi_sendmsg(int fd, struct msghdr __user *msg, unsigned flags) 412 { 413 struct sockaddr __user *addr; 414 int msg_namelen; 415 sa_family_t sa_family; 416 if (msg && 417 get_user(msg_namelen, &msg->msg_namelen) == 0 && 418 msg_namelen == 112 && 419 get_user(addr, &msg->msg_name) == 0 && 420 get_user(sa_family, &addr->sa_family) == 0 && 421 sa_family == AF_UNIX) 422 { 423 /* 424 * HACK ALERT: there is a limit to how much backward bending 425 * we should do for what is actually a transitional 426 * compatibility layer. This already has known flaws with 427 * a few ioctls that we don't intend to fix. Therefore 428 * consider this blatent hack as another one... and take care 429 * to run for cover. In most cases it will "just work fine". 430 * If it doesn't, well, tough. 431 */ 432 put_user(110, &msg->msg_namelen); 433 } 434 return sys_sendmsg(fd, msg, flags); 435 } 436 437 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args) 438 { 439 unsigned long r = -EFAULT, a[6]; 440 441 switch (call) { 442 case SYS_BIND: 443 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 444 r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]); 445 break; 446 case SYS_CONNECT: 447 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 448 r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]); 449 break; 450 case SYS_SENDTO: 451 if (copy_from_user(a, args, 6 * sizeof(long)) == 0) 452 r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3], 453 (struct sockaddr __user *)a[4], a[5]); 454 break; 455 case SYS_SENDMSG: 456 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 457 r = sys_oabi_sendmsg(a[0], (struct msghdr __user *)a[1], a[2]); 458 break; 459 default: 460 r = sys_socketcall(call, args); 461 } 462 463 return r; 464 } 465