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 <linux/uaccess.h> 86 #include <linux/slab.h> 87 88 struct oldabi_stat64 { 89 unsigned long long st_dev; 90 unsigned int __pad1; 91 unsigned long __st_ino; 92 unsigned int st_mode; 93 unsigned int st_nlink; 94 95 unsigned long st_uid; 96 unsigned long st_gid; 97 98 unsigned long long st_rdev; 99 unsigned int __pad2; 100 101 long long st_size; 102 unsigned long st_blksize; 103 unsigned long long st_blocks; 104 105 unsigned long st_atime; 106 unsigned long st_atime_nsec; 107 108 unsigned long st_mtime; 109 unsigned long st_mtime_nsec; 110 111 unsigned long st_ctime; 112 unsigned long st_ctime_nsec; 113 114 unsigned long long st_ino; 115 } __attribute__ ((packed,aligned(4))); 116 117 static long cp_oldabi_stat64(struct kstat *stat, 118 struct oldabi_stat64 __user *statbuf) 119 { 120 struct oldabi_stat64 tmp; 121 122 tmp.st_dev = huge_encode_dev(stat->dev); 123 tmp.__pad1 = 0; 124 tmp.__st_ino = stat->ino; 125 tmp.st_mode = stat->mode; 126 tmp.st_nlink = stat->nlink; 127 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid); 128 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid); 129 tmp.st_rdev = huge_encode_dev(stat->rdev); 130 tmp.st_size = stat->size; 131 tmp.st_blocks = stat->blocks; 132 tmp.__pad2 = 0; 133 tmp.st_blksize = stat->blksize; 134 tmp.st_atime = stat->atime.tv_sec; 135 tmp.st_atime_nsec = stat->atime.tv_nsec; 136 tmp.st_mtime = stat->mtime.tv_sec; 137 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 138 tmp.st_ctime = stat->ctime.tv_sec; 139 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 140 tmp.st_ino = stat->ino; 141 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 142 } 143 144 asmlinkage long sys_oabi_stat64(const char __user * filename, 145 struct oldabi_stat64 __user * statbuf) 146 { 147 struct kstat stat; 148 int error = vfs_stat(filename, &stat); 149 if (!error) 150 error = cp_oldabi_stat64(&stat, statbuf); 151 return error; 152 } 153 154 asmlinkage long sys_oabi_lstat64(const char __user * filename, 155 struct oldabi_stat64 __user * statbuf) 156 { 157 struct kstat stat; 158 int error = vfs_lstat(filename, &stat); 159 if (!error) 160 error = cp_oldabi_stat64(&stat, statbuf); 161 return error; 162 } 163 164 asmlinkage long sys_oabi_fstat64(unsigned long fd, 165 struct oldabi_stat64 __user * statbuf) 166 { 167 struct kstat stat; 168 int error = vfs_fstat(fd, &stat); 169 if (!error) 170 error = cp_oldabi_stat64(&stat, statbuf); 171 return error; 172 } 173 174 asmlinkage long sys_oabi_fstatat64(int dfd, 175 const char __user *filename, 176 struct oldabi_stat64 __user *statbuf, 177 int flag) 178 { 179 struct kstat stat; 180 int error; 181 182 error = vfs_fstatat(dfd, filename, &stat, flag); 183 if (error) 184 return error; 185 return cp_oldabi_stat64(&stat, statbuf); 186 } 187 188 struct oabi_flock64 { 189 short l_type; 190 short l_whence; 191 loff_t l_start; 192 loff_t l_len; 193 pid_t l_pid; 194 } __attribute__ ((packed,aligned(4))); 195 196 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd, 197 unsigned long arg) 198 { 199 struct oabi_flock64 user; 200 struct flock64 kernel; 201 mm_segment_t fs = USER_DS; /* initialized to kill a warning */ 202 unsigned long local_arg = arg; 203 int ret; 204 205 switch (cmd) { 206 case F_OFD_GETLK: 207 case F_OFD_SETLK: 208 case F_OFD_SETLKW: 209 case F_GETLK64: 210 case F_SETLK64: 211 case F_SETLKW64: 212 if (copy_from_user(&user, (struct oabi_flock64 __user *)arg, 213 sizeof(user))) 214 return -EFAULT; 215 kernel.l_type = user.l_type; 216 kernel.l_whence = user.l_whence; 217 kernel.l_start = user.l_start; 218 kernel.l_len = user.l_len; 219 kernel.l_pid = user.l_pid; 220 local_arg = (unsigned long)&kernel; 221 fs = get_fs(); 222 set_fs(KERNEL_DS); 223 } 224 225 ret = sys_fcntl64(fd, cmd, local_arg); 226 227 switch (cmd) { 228 case F_GETLK64: 229 if (!ret) { 230 user.l_type = kernel.l_type; 231 user.l_whence = kernel.l_whence; 232 user.l_start = kernel.l_start; 233 user.l_len = kernel.l_len; 234 user.l_pid = kernel.l_pid; 235 if (copy_to_user((struct oabi_flock64 __user *)arg, 236 &user, sizeof(user))) 237 ret = -EFAULT; 238 } 239 case F_SETLK64: 240 case F_SETLKW64: 241 set_fs(fs); 242 } 243 244 return ret; 245 } 246 247 struct oabi_epoll_event { 248 __u32 events; 249 __u64 data; 250 } __attribute__ ((packed,aligned(4))); 251 252 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd, 253 struct oabi_epoll_event __user *event) 254 { 255 struct oabi_epoll_event user; 256 struct epoll_event kernel; 257 mm_segment_t fs; 258 long ret; 259 260 if (op == EPOLL_CTL_DEL) 261 return sys_epoll_ctl(epfd, op, fd, NULL); 262 if (copy_from_user(&user, event, sizeof(user))) 263 return -EFAULT; 264 kernel.events = user.events; 265 kernel.data = user.data; 266 fs = get_fs(); 267 set_fs(KERNEL_DS); 268 ret = sys_epoll_ctl(epfd, op, fd, &kernel); 269 set_fs(fs); 270 return ret; 271 } 272 273 asmlinkage long sys_oabi_epoll_wait(int epfd, 274 struct oabi_epoll_event __user *events, 275 int maxevents, int timeout) 276 { 277 struct epoll_event *kbuf; 278 mm_segment_t fs; 279 long ret, err, i; 280 281 if (maxevents <= 0 || maxevents > (INT_MAX/sizeof(struct epoll_event))) 282 return -EINVAL; 283 kbuf = kmalloc(sizeof(*kbuf) * maxevents, GFP_KERNEL); 284 if (!kbuf) 285 return -ENOMEM; 286 fs = get_fs(); 287 set_fs(KERNEL_DS); 288 ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout); 289 set_fs(fs); 290 err = 0; 291 for (i = 0; i < ret; i++) { 292 __put_user_error(kbuf[i].events, &events->events, err); 293 __put_user_error(kbuf[i].data, &events->data, err); 294 events++; 295 } 296 kfree(kbuf); 297 return err ? -EFAULT : ret; 298 } 299 300 struct oabi_sembuf { 301 unsigned short sem_num; 302 short sem_op; 303 short sem_flg; 304 unsigned short __pad; 305 }; 306 307 asmlinkage long sys_oabi_semtimedop(int semid, 308 struct oabi_sembuf __user *tsops, 309 unsigned nsops, 310 const struct timespec __user *timeout) 311 { 312 struct sembuf *sops; 313 struct timespec local_timeout; 314 long err; 315 int i; 316 317 if (nsops < 1 || nsops > SEMOPM) 318 return -EINVAL; 319 sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL); 320 if (!sops) 321 return -ENOMEM; 322 err = 0; 323 for (i = 0; i < nsops; i++) { 324 __get_user_error(sops[i].sem_num, &tsops->sem_num, err); 325 __get_user_error(sops[i].sem_op, &tsops->sem_op, err); 326 __get_user_error(sops[i].sem_flg, &tsops->sem_flg, err); 327 tsops++; 328 } 329 if (timeout) { 330 /* copy this as well before changing domain protection */ 331 err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout)); 332 timeout = &local_timeout; 333 } 334 if (err) { 335 err = -EFAULT; 336 } else { 337 mm_segment_t fs = get_fs(); 338 set_fs(KERNEL_DS); 339 err = sys_semtimedop(semid, sops, nsops, timeout); 340 set_fs(fs); 341 } 342 kfree(sops); 343 return err; 344 } 345 346 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops, 347 unsigned nsops) 348 { 349 return sys_oabi_semtimedop(semid, tsops, nsops, NULL); 350 } 351 352 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third, 353 void __user *ptr, long fifth) 354 { 355 switch (call & 0xffff) { 356 case SEMOP: 357 return sys_oabi_semtimedop(first, 358 (struct oabi_sembuf __user *)ptr, 359 second, NULL); 360 case SEMTIMEDOP: 361 return sys_oabi_semtimedop(first, 362 (struct oabi_sembuf __user *)ptr, 363 second, 364 (const struct timespec __user *)fifth); 365 default: 366 return sys_ipc(call, first, second, third, ptr, fifth); 367 } 368 } 369 370 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen) 371 { 372 sa_family_t sa_family; 373 if (addrlen == 112 && 374 get_user(sa_family, &addr->sa_family) == 0 && 375 sa_family == AF_UNIX) 376 addrlen = 110; 377 return sys_bind(fd, addr, addrlen); 378 } 379 380 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen) 381 { 382 sa_family_t sa_family; 383 if (addrlen == 112 && 384 get_user(sa_family, &addr->sa_family) == 0 && 385 sa_family == AF_UNIX) 386 addrlen = 110; 387 return sys_connect(fd, addr, addrlen); 388 } 389 390 asmlinkage long sys_oabi_sendto(int fd, void __user *buff, 391 size_t len, unsigned flags, 392 struct sockaddr __user *addr, 393 int addrlen) 394 { 395 sa_family_t sa_family; 396 if (addrlen == 112 && 397 get_user(sa_family, &addr->sa_family) == 0 && 398 sa_family == AF_UNIX) 399 addrlen = 110; 400 return sys_sendto(fd, buff, len, flags, addr, addrlen); 401 } 402 403 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags) 404 { 405 struct sockaddr __user *addr; 406 int msg_namelen; 407 sa_family_t sa_family; 408 if (msg && 409 get_user(msg_namelen, &msg->msg_namelen) == 0 && 410 msg_namelen == 112 && 411 get_user(addr, &msg->msg_name) == 0 && 412 get_user(sa_family, &addr->sa_family) == 0 && 413 sa_family == AF_UNIX) 414 { 415 /* 416 * HACK ALERT: there is a limit to how much backward bending 417 * we should do for what is actually a transitional 418 * compatibility layer. This already has known flaws with 419 * a few ioctls that we don't intend to fix. Therefore 420 * consider this blatent hack as another one... and take care 421 * to run for cover. In most cases it will "just work fine". 422 * If it doesn't, well, tough. 423 */ 424 put_user(110, &msg->msg_namelen); 425 } 426 return sys_sendmsg(fd, msg, flags); 427 } 428 429 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args) 430 { 431 unsigned long r = -EFAULT, a[6]; 432 433 switch (call) { 434 case SYS_BIND: 435 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 436 r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]); 437 break; 438 case SYS_CONNECT: 439 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 440 r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]); 441 break; 442 case SYS_SENDTO: 443 if (copy_from_user(a, args, 6 * sizeof(long)) == 0) 444 r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3], 445 (struct sockaddr __user *)a[4], a[5]); 446 break; 447 case SYS_SENDMSG: 448 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 449 r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]); 450 break; 451 default: 452 r = sys_socketcall(call, args); 453 } 454 455 return r; 456 } 457