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 88struct 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 117static 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 = stat->uid; 128 tmp.st_gid = 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 144asmlinkage 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 154asmlinkage 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 164asmlinkage 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 174asmlinkage 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 188struct 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 196asmlinkage 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_GETLK64: 207 case F_SETLK64: 208 case F_SETLKW64: 209 if (copy_from_user(&user, (struct oabi_flock64 __user *)arg, 210 sizeof(user))) 211 return -EFAULT; 212 kernel.l_type = user.l_type; 213 kernel.l_whence = user.l_whence; 214 kernel.l_start = user.l_start; 215 kernel.l_len = user.l_len; 216 kernel.l_pid = user.l_pid; 217 local_arg = (unsigned long)&kernel; 218 fs = get_fs(); 219 set_fs(KERNEL_DS); 220 } 221 222 ret = sys_fcntl64(fd, cmd, local_arg); 223 224 switch (cmd) { 225 case F_GETLK64: 226 if (!ret) { 227 user.l_type = kernel.l_type; 228 user.l_whence = kernel.l_whence; 229 user.l_start = kernel.l_start; 230 user.l_len = kernel.l_len; 231 user.l_pid = kernel.l_pid; 232 if (copy_to_user((struct oabi_flock64 __user *)arg, 233 &user, sizeof(user))) 234 ret = -EFAULT; 235 } 236 case F_SETLK64: 237 case F_SETLKW64: 238 set_fs(fs); 239 } 240 241 return ret; 242} 243 244struct oabi_epoll_event { 245 __u32 events; 246 __u64 data; 247} __attribute__ ((packed,aligned(4))); 248 249asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd, 250 struct oabi_epoll_event __user *event) 251{ 252 struct oabi_epoll_event user; 253 struct epoll_event kernel; 254 mm_segment_t fs; 255 long ret; 256 257 if (op == EPOLL_CTL_DEL) 258 return sys_epoll_ctl(epfd, op, fd, NULL); 259 if (copy_from_user(&user, event, sizeof(user))) 260 return -EFAULT; 261 kernel.events = user.events; 262 kernel.data = user.data; 263 fs = get_fs(); 264 set_fs(KERNEL_DS); 265 ret = sys_epoll_ctl(epfd, op, fd, &kernel); 266 set_fs(fs); 267 return ret; 268} 269 270asmlinkage long sys_oabi_epoll_wait(int epfd, 271 struct oabi_epoll_event __user *events, 272 int maxevents, int timeout) 273{ 274 struct epoll_event *kbuf; 275 mm_segment_t fs; 276 long ret, err, i; 277 278 if (maxevents <= 0 || maxevents > (INT_MAX/sizeof(struct epoll_event))) 279 return -EINVAL; 280 kbuf = kmalloc(sizeof(*kbuf) * maxevents, GFP_KERNEL); 281 if (!kbuf) 282 return -ENOMEM; 283 fs = get_fs(); 284 set_fs(KERNEL_DS); 285 ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout); 286 set_fs(fs); 287 err = 0; 288 for (i = 0; i < ret; i++) { 289 __put_user_error(kbuf[i].events, &events->events, err); 290 __put_user_error(kbuf[i].data, &events->data, err); 291 events++; 292 } 293 kfree(kbuf); 294 return err ? -EFAULT : ret; 295} 296 297struct oabi_sembuf { 298 unsigned short sem_num; 299 short sem_op; 300 short sem_flg; 301 unsigned short __pad; 302}; 303 304asmlinkage long sys_oabi_semtimedop(int semid, 305 struct oabi_sembuf __user *tsops, 306 unsigned nsops, 307 const struct timespec __user *timeout) 308{ 309 struct sembuf *sops; 310 struct timespec local_timeout; 311 long err; 312 int i; 313 314 if (nsops < 1) 315 return -EINVAL; 316 sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL); 317 if (!sops) 318 return -ENOMEM; 319 err = 0; 320 for (i = 0; i < nsops; i++) { 321 __get_user_error(sops[i].sem_num, &tsops->sem_num, err); 322 __get_user_error(sops[i].sem_op, &tsops->sem_op, err); 323 __get_user_error(sops[i].sem_flg, &tsops->sem_flg, err); 324 tsops++; 325 } 326 if (timeout) { 327 /* copy this as well before changing domain protection */ 328 err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout)); 329 timeout = &local_timeout; 330 } 331 if (err) { 332 err = -EFAULT; 333 } else { 334 mm_segment_t fs = get_fs(); 335 set_fs(KERNEL_DS); 336 err = sys_semtimedop(semid, sops, nsops, timeout); 337 set_fs(fs); 338 } 339 kfree(sops); 340 return err; 341} 342 343asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops, 344 unsigned nsops) 345{ 346 return sys_oabi_semtimedop(semid, tsops, nsops, NULL); 347} 348 349asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third, 350 void __user *ptr, long fifth) 351{ 352 switch (call & 0xffff) { 353 case SEMOP: 354 return sys_oabi_semtimedop(first, 355 (struct oabi_sembuf __user *)ptr, 356 second, NULL); 357 case SEMTIMEDOP: 358 return sys_oabi_semtimedop(first, 359 (struct oabi_sembuf __user *)ptr, 360 second, 361 (const struct timespec __user *)fifth); 362 default: 363 return sys_ipc(call, first, second, third, ptr, fifth); 364 } 365} 366 367asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen) 368{ 369 sa_family_t sa_family; 370 if (addrlen == 112 && 371 get_user(sa_family, &addr->sa_family) == 0 && 372 sa_family == AF_UNIX) 373 addrlen = 110; 374 return sys_bind(fd, addr, addrlen); 375} 376 377asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen) 378{ 379 sa_family_t sa_family; 380 if (addrlen == 112 && 381 get_user(sa_family, &addr->sa_family) == 0 && 382 sa_family == AF_UNIX) 383 addrlen = 110; 384 return sys_connect(fd, addr, addrlen); 385} 386 387asmlinkage long sys_oabi_sendto(int fd, void __user *buff, 388 size_t len, unsigned flags, 389 struct sockaddr __user *addr, 390 int addrlen) 391{ 392 sa_family_t sa_family; 393 if (addrlen == 112 && 394 get_user(sa_family, &addr->sa_family) == 0 && 395 sa_family == AF_UNIX) 396 addrlen = 110; 397 return sys_sendto(fd, buff, len, flags, addr, addrlen); 398} 399 400asmlinkage long sys_oabi_sendmsg(int fd, struct msghdr __user *msg, unsigned flags) 401{ 402 struct sockaddr __user *addr; 403 int msg_namelen; 404 sa_family_t sa_family; 405 if (msg && 406 get_user(msg_namelen, &msg->msg_namelen) == 0 && 407 msg_namelen == 112 && 408 get_user(addr, &msg->msg_name) == 0 && 409 get_user(sa_family, &addr->sa_family) == 0 && 410 sa_family == AF_UNIX) 411 { 412 /* 413 * HACK ALERT: there is a limit to how much backward bending 414 * we should do for what is actually a transitional 415 * compatibility layer. This already has known flaws with 416 * a few ioctls that we don't intend to fix. Therefore 417 * consider this blatent hack as another one... and take care 418 * to run for cover. In most cases it will "just work fine". 419 * If it doesn't, well, tough. 420 */ 421 put_user(110, &msg->msg_namelen); 422 } 423 return sys_sendmsg(fd, msg, flags); 424} 425 426asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args) 427{ 428 unsigned long r = -EFAULT, a[6]; 429 430 switch (call) { 431 case SYS_BIND: 432 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 433 r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]); 434 break; 435 case SYS_CONNECT: 436 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 437 r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]); 438 break; 439 case SYS_SENDTO: 440 if (copy_from_user(a, args, 6 * sizeof(long)) == 0) 441 r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3], 442 (struct sockaddr __user *)a[4], a[5]); 443 break; 444 case SYS_SENDMSG: 445 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 446 r = sys_oabi_sendmsg(a[0], (struct msghdr __user *)a[1], a[2]); 447 break; 448 default: 449 r = sys_socketcall(call, args); 450 } 451 452 return r; 453} 454