1 // SPDX-License-Identifier: GPL-2.0-only
3 * arch/arm/kernel/sys_oabi-compat.c
5 * Compatibility wrappers for syscalls that are used from
6 * old ABI user space binaries with an EABI kernel.
8 * Author: Nicolas Pitre
10 * Copyright: MontaVista Software, Inc.
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.
20 * The following syscalls are affected:
27 * struct stat64 has different sizes and some members are shifted
28 * Compatibility wrappers are needed for them and provided below.
32 * struct flock64 has different sizes and some members are shifted
33 * A compatibility wrapper is needed and provided below.
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.
45 * struct new_utsname has no padding with EABI. No problem there.
50 * struct epoll_event has its second member shifted also affecting the
51 * structure size. Compatibility wrappers are needed and provided below.
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
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.
73 #include <linux/syscalls.h>
74 #include <linux/errno.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/uaccess.h>
84 #include <linux/slab.h>
86 struct oldabi_stat64 {
87 unsigned long long st_dev;
89 unsigned long __st_ino;
91 unsigned int st_nlink;
96 unsigned long long st_rdev;
100 unsigned long st_blksize;
101 unsigned long long st_blocks;
103 unsigned long st_atime;
104 unsigned long st_atime_nsec;
106 unsigned long st_mtime;
107 unsigned long st_mtime_nsec;
109 unsigned long st_ctime;
110 unsigned long st_ctime_nsec;
112 unsigned long long st_ino;
113 } __attribute__ ((packed,aligned(4)));
115 static long cp_oldabi_stat64(struct kstat *stat,
116 struct oldabi_stat64 __user *statbuf)
118 struct oldabi_stat64 tmp;
120 tmp.st_dev = huge_encode_dev(stat->dev);
122 tmp.__st_ino = stat->ino;
123 tmp.st_mode = stat->mode;
124 tmp.st_nlink = stat->nlink;
125 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
126 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
127 tmp.st_rdev = huge_encode_dev(stat->rdev);
128 tmp.st_size = stat->size;
129 tmp.st_blocks = stat->blocks;
131 tmp.st_blksize = stat->blksize;
132 tmp.st_atime = stat->atime.tv_sec;
133 tmp.st_atime_nsec = stat->atime.tv_nsec;
134 tmp.st_mtime = stat->mtime.tv_sec;
135 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
136 tmp.st_ctime = stat->ctime.tv_sec;
137 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
138 tmp.st_ino = stat->ino;
139 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
142 asmlinkage long sys_oabi_stat64(const char __user * filename,
143 struct oldabi_stat64 __user * statbuf)
146 int error = vfs_stat(filename, &stat);
148 error = cp_oldabi_stat64(&stat, statbuf);
152 asmlinkage long sys_oabi_lstat64(const char __user * filename,
153 struct oldabi_stat64 __user * statbuf)
156 int error = vfs_lstat(filename, &stat);
158 error = cp_oldabi_stat64(&stat, statbuf);
162 asmlinkage long sys_oabi_fstat64(unsigned long fd,
163 struct oldabi_stat64 __user * statbuf)
166 int error = vfs_fstat(fd, &stat);
168 error = cp_oldabi_stat64(&stat, statbuf);
172 asmlinkage long sys_oabi_fstatat64(int dfd,
173 const char __user *filename,
174 struct oldabi_stat64 __user *statbuf,
180 error = vfs_fstatat(dfd, filename, &stat, flag);
183 return cp_oldabi_stat64(&stat, statbuf);
186 struct oabi_flock64 {
192 } __attribute__ ((packed,aligned(4)));
194 static long do_locks(unsigned int fd, unsigned int cmd,
197 struct flock64 kernel;
198 struct oabi_flock64 user;
202 if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
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;
213 ret = sys_fcntl64(fd, cmd, (unsigned long)&kernel);
216 if (!ret && (cmd == F_GETLK64 || cmd == F_OFD_GETLK)) {
217 user.l_type = kernel.l_type;
218 user.l_whence = kernel.l_whence;
219 user.l_start = kernel.l_start;
220 user.l_len = kernel.l_len;
221 user.l_pid = kernel.l_pid;
222 if (copy_to_user((struct oabi_flock64 __user *)arg,
223 &user, sizeof(user)))
229 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
239 return do_locks(fd, cmd, arg);
242 return sys_fcntl64(fd, cmd, arg);
246 struct oabi_epoll_event {
249 } __attribute__ ((packed,aligned(4)));
252 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
253 struct oabi_epoll_event __user *event)
255 struct oabi_epoll_event user;
256 struct epoll_event kernel;
258 if (ep_op_has_event(op) &&
259 copy_from_user(&user, event, sizeof(user)))
262 kernel.events = user.events;
263 kernel.data = user.data;
265 return do_epoll_ctl(epfd, op, fd, &kernel, false);
268 asmlinkage long sys_oabi_epoll_wait(int epfd,
269 struct oabi_epoll_event __user *events,
270 int maxevents, int timeout)
272 struct epoll_event *kbuf;
273 struct oabi_epoll_event e;
277 if (maxevents <= 0 ||
278 maxevents > (INT_MAX/sizeof(*kbuf)) ||
279 maxevents > (INT_MAX/sizeof(*events)))
281 if (!access_ok(events, sizeof(*events) * maxevents))
283 kbuf = kmalloc_array(maxevents, sizeof(*kbuf), GFP_KERNEL);
288 ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout);
291 for (i = 0; i < ret; i++) {
292 e.events = kbuf[i].events;
293 e.data = kbuf[i].data;
294 err = __copy_to_user(events, &e, sizeof(e));
300 return err ? -EFAULT : ret;
303 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
304 struct oabi_epoll_event __user *event)
309 asmlinkage long sys_oabi_epoll_wait(int epfd,
310 struct oabi_epoll_event __user *events,
311 int maxevents, int timeout)
318 unsigned short sem_num;
321 unsigned short __pad;
324 asmlinkage long sys_oabi_semtimedop(int semid,
325 struct oabi_sembuf __user *tsops,
327 const struct old_timespec32 __user *timeout)
330 struct old_timespec32 local_timeout;
334 if (nsops < 1 || nsops > SEMOPM)
336 if (!access_ok(tsops, sizeof(*tsops) * nsops))
338 sops = kmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
342 for (i = 0; i < nsops; i++) {
343 struct oabi_sembuf osb;
344 err |= __copy_from_user(&osb, tsops, sizeof(osb));
345 sops[i].sem_num = osb.sem_num;
346 sops[i].sem_op = osb.sem_op;
347 sops[i].sem_flg = osb.sem_flg;
351 /* copy this as well before changing domain protection */
352 err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout));
353 timeout = &local_timeout;
358 mm_segment_t fs = get_fs();
360 err = sys_semtimedop_time32(semid, sops, nsops, timeout);
367 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
370 return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
373 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
374 void __user *ptr, long fifth)
376 switch (call & 0xffff) {
378 return sys_oabi_semtimedop(first,
379 (struct oabi_sembuf __user *)ptr,
382 return sys_oabi_semtimedop(first,
383 (struct oabi_sembuf __user *)ptr,
385 (const struct old_timespec32 __user *)fifth);
387 return sys_ipc(call, first, second, third, ptr, fifth);
391 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
393 sa_family_t sa_family;
394 if (addrlen == 112 &&
395 get_user(sa_family, &addr->sa_family) == 0 &&
396 sa_family == AF_UNIX)
398 return sys_bind(fd, addr, addrlen);
401 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
403 sa_family_t sa_family;
404 if (addrlen == 112 &&
405 get_user(sa_family, &addr->sa_family) == 0 &&
406 sa_family == AF_UNIX)
408 return sys_connect(fd, addr, addrlen);
411 asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
412 size_t len, unsigned flags,
413 struct sockaddr __user *addr,
416 sa_family_t sa_family;
417 if (addrlen == 112 &&
418 get_user(sa_family, &addr->sa_family) == 0 &&
419 sa_family == AF_UNIX)
421 return sys_sendto(fd, buff, len, flags, addr, addrlen);
424 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags)
426 struct sockaddr __user *addr;
428 sa_family_t sa_family;
430 get_user(msg_namelen, &msg->msg_namelen) == 0 &&
431 msg_namelen == 112 &&
432 get_user(addr, &msg->msg_name) == 0 &&
433 get_user(sa_family, &addr->sa_family) == 0 &&
434 sa_family == AF_UNIX)
437 * HACK ALERT: there is a limit to how much backward bending
438 * we should do for what is actually a transitional
439 * compatibility layer. This already has known flaws with
440 * a few ioctls that we don't intend to fix. Therefore
441 * consider this blatent hack as another one... and take care
442 * to run for cover. In most cases it will "just work fine".
443 * If it doesn't, well, tough.
445 put_user(110, &msg->msg_namelen);
447 return sys_sendmsg(fd, msg, flags);
450 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
452 unsigned long r = -EFAULT, a[6];
456 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
457 r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
460 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
461 r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
464 if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
465 r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
466 (struct sockaddr __user *)a[4], a[5]);
469 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
470 r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]);
473 r = sys_socketcall(call, args);