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/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/uaccess.h> 87 #include <linux/slab.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 long do_locks(unsigned int fd, unsigned int cmd, 198 unsigned long arg) 199 { 200 struct flock64 kernel; 201 struct oabi_flock64 user; 202 mm_segment_t fs; 203 long ret; 204 205 if (copy_from_user(&user, (struct oabi_flock64 __user *)arg, 206 sizeof(user))) 207 return -EFAULT; 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 fs = get_fs(); 215 set_fs(KERNEL_DS); 216 ret = sys_fcntl64(fd, cmd, (unsigned long)&kernel); 217 set_fs(fs); 218 219 if (!ret && (cmd == F_GETLK64 || cmd == F_OFD_GETLK)) { 220 user.l_type = kernel.l_type; 221 user.l_whence = kernel.l_whence; 222 user.l_start = kernel.l_start; 223 user.l_len = kernel.l_len; 224 user.l_pid = kernel.l_pid; 225 if (copy_to_user((struct oabi_flock64 __user *)arg, 226 &user, sizeof(user))) 227 ret = -EFAULT; 228 } 229 return ret; 230 } 231 232 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd, 233 unsigned long arg) 234 { 235 switch (cmd) { 236 case F_OFD_GETLK: 237 case F_OFD_SETLK: 238 case F_OFD_SETLKW: 239 case F_GETLK64: 240 case F_SETLK64: 241 case F_SETLKW64: 242 return do_locks(fd, cmd, arg); 243 244 default: 245 return sys_fcntl64(fd, cmd, arg); 246 } 247 } 248 249 struct oabi_epoll_event { 250 __u32 events; 251 __u64 data; 252 } __attribute__ ((packed,aligned(4))); 253 254 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd, 255 struct oabi_epoll_event __user *event) 256 { 257 struct oabi_epoll_event user; 258 struct epoll_event kernel; 259 mm_segment_t fs; 260 long ret; 261 262 if (op == EPOLL_CTL_DEL) 263 return sys_epoll_ctl(epfd, op, fd, NULL); 264 if (copy_from_user(&user, event, sizeof(user))) 265 return -EFAULT; 266 kernel.events = user.events; 267 kernel.data = user.data; 268 fs = get_fs(); 269 set_fs(KERNEL_DS); 270 ret = sys_epoll_ctl(epfd, op, fd, &kernel); 271 set_fs(fs); 272 return ret; 273 } 274 275 asmlinkage long sys_oabi_epoll_wait(int epfd, 276 struct oabi_epoll_event __user *events, 277 int maxevents, int timeout) 278 { 279 struct epoll_event *kbuf; 280 struct oabi_epoll_event e; 281 mm_segment_t fs; 282 long ret, err, i; 283 284 if (maxevents <= 0 || 285 maxevents > (INT_MAX/sizeof(*kbuf)) || 286 maxevents > (INT_MAX/sizeof(*events))) 287 return -EINVAL; 288 if (!access_ok(events, sizeof(*events) * maxevents)) 289 return -EFAULT; 290 kbuf = kmalloc_array(maxevents, sizeof(*kbuf), GFP_KERNEL); 291 if (!kbuf) 292 return -ENOMEM; 293 fs = get_fs(); 294 set_fs(KERNEL_DS); 295 ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout); 296 set_fs(fs); 297 err = 0; 298 for (i = 0; i < ret; i++) { 299 e.events = kbuf[i].events; 300 e.data = kbuf[i].data; 301 err = __copy_to_user(events, &e, sizeof(e)); 302 if (err) 303 break; 304 events++; 305 } 306 kfree(kbuf); 307 return err ? -EFAULT : ret; 308 } 309 310 struct oabi_sembuf { 311 unsigned short sem_num; 312 short sem_op; 313 short sem_flg; 314 unsigned short __pad; 315 }; 316 317 asmlinkage long sys_oabi_semtimedop(int semid, 318 struct oabi_sembuf __user *tsops, 319 unsigned nsops, 320 const struct timespec __user *timeout) 321 { 322 struct sembuf *sops; 323 struct timespec local_timeout; 324 long err; 325 int i; 326 327 if (nsops < 1 || nsops > SEMOPM) 328 return -EINVAL; 329 if (!access_ok(tsops, sizeof(*tsops) * nsops)) 330 return -EFAULT; 331 sops = kmalloc_array(nsops, sizeof(*sops), GFP_KERNEL); 332 if (!sops) 333 return -ENOMEM; 334 err = 0; 335 for (i = 0; i < nsops; i++) { 336 struct oabi_sembuf osb; 337 err |= __copy_from_user(&osb, tsops, sizeof(osb)); 338 sops[i].sem_num = osb.sem_num; 339 sops[i].sem_op = osb.sem_op; 340 sops[i].sem_flg = osb.sem_flg; 341 tsops++; 342 } 343 if (timeout) { 344 /* copy this as well before changing domain protection */ 345 err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout)); 346 timeout = &local_timeout; 347 } 348 if (err) { 349 err = -EFAULT; 350 } else { 351 mm_segment_t fs = get_fs(); 352 set_fs(KERNEL_DS); 353 err = sys_semtimedop(semid, sops, nsops, timeout); 354 set_fs(fs); 355 } 356 kfree(sops); 357 return err; 358 } 359 360 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops, 361 unsigned nsops) 362 { 363 return sys_oabi_semtimedop(semid, tsops, nsops, NULL); 364 } 365 366 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third, 367 void __user *ptr, long fifth) 368 { 369 switch (call & 0xffff) { 370 case SEMOP: 371 return sys_oabi_semtimedop(first, 372 (struct oabi_sembuf __user *)ptr, 373 second, NULL); 374 case SEMTIMEDOP: 375 return sys_oabi_semtimedop(first, 376 (struct oabi_sembuf __user *)ptr, 377 second, 378 (const struct timespec __user *)fifth); 379 default: 380 return sys_ipc(call, first, second, third, ptr, fifth); 381 } 382 } 383 384 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen) 385 { 386 sa_family_t sa_family; 387 if (addrlen == 112 && 388 get_user(sa_family, &addr->sa_family) == 0 && 389 sa_family == AF_UNIX) 390 addrlen = 110; 391 return sys_bind(fd, addr, addrlen); 392 } 393 394 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen) 395 { 396 sa_family_t sa_family; 397 if (addrlen == 112 && 398 get_user(sa_family, &addr->sa_family) == 0 && 399 sa_family == AF_UNIX) 400 addrlen = 110; 401 return sys_connect(fd, addr, addrlen); 402 } 403 404 asmlinkage long sys_oabi_sendto(int fd, void __user *buff, 405 size_t len, unsigned flags, 406 struct sockaddr __user *addr, 407 int addrlen) 408 { 409 sa_family_t sa_family; 410 if (addrlen == 112 && 411 get_user(sa_family, &addr->sa_family) == 0 && 412 sa_family == AF_UNIX) 413 addrlen = 110; 414 return sys_sendto(fd, buff, len, flags, addr, addrlen); 415 } 416 417 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags) 418 { 419 struct sockaddr __user *addr; 420 int msg_namelen; 421 sa_family_t sa_family; 422 if (msg && 423 get_user(msg_namelen, &msg->msg_namelen) == 0 && 424 msg_namelen == 112 && 425 get_user(addr, &msg->msg_name) == 0 && 426 get_user(sa_family, &addr->sa_family) == 0 && 427 sa_family == AF_UNIX) 428 { 429 /* 430 * HACK ALERT: there is a limit to how much backward bending 431 * we should do for what is actually a transitional 432 * compatibility layer. This already has known flaws with 433 * a few ioctls that we don't intend to fix. Therefore 434 * consider this blatent hack as another one... and take care 435 * to run for cover. In most cases it will "just work fine". 436 * If it doesn't, well, tough. 437 */ 438 put_user(110, &msg->msg_namelen); 439 } 440 return sys_sendmsg(fd, msg, flags); 441 } 442 443 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args) 444 { 445 unsigned long r = -EFAULT, a[6]; 446 447 switch (call) { 448 case SYS_BIND: 449 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 450 r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]); 451 break; 452 case SYS_CONNECT: 453 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 454 r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]); 455 break; 456 case SYS_SENDTO: 457 if (copy_from_user(a, args, 6 * sizeof(long)) == 0) 458 r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3], 459 (struct sockaddr __user *)a[4], a[5]); 460 break; 461 case SYS_SENDMSG: 462 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 463 r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]); 464 break; 465 default: 466 r = sys_socketcall(call, args); 467 } 468 469 return r; 470 } 471