xref: /linux/arch/arm/kernel/sys_oabi-compat.c (revision 55d0969c451159cff86949b38c39171cab962069)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  arch/arm/kernel/sys_oabi-compat.c
4  *
5  *  Compatibility wrappers for syscalls that are used from
6  *  old ABI user space binaries with an EABI kernel.
7  *
8  *  Author:	Nicolas Pitre
9  *  Created:	Oct 7, 2005
10  *  Copyright:	MontaVista Software, Inc.
11  */
12 
13 #include <asm/syscalls.h>
14 
15 /*
16  * The legacy ABI and the new ARM EABI have different rules making some
17  * syscalls incompatible especially with structure arguments.
18  * Most notably, Eabi says 64-bit members should be 64-bit aligned instead of
19  * simply word aligned.  EABI also pads structures to the size of the largest
20  * member it contains instead of the invariant 32-bit.
21  *
22  * The following syscalls are affected:
23  *
24  * sys_stat64:
25  * sys_lstat64:
26  * sys_fstat64:
27  * sys_fstatat64:
28  *
29  *   struct stat64 has different sizes and some members are shifted
30  *   Compatibility wrappers are needed for them and provided below.
31  *
32  * sys_fcntl64:
33  *
34  *   struct flock64 has different sizes and some members are shifted
35  *   A compatibility wrapper is needed and provided below.
36  *
37  * sys_statfs64:
38  * sys_fstatfs64:
39  *
40  *   struct statfs64 has extra padding with EABI growing its size from
41  *   84 to 88.  This struct is now __attribute__((packed,aligned(4)))
42  *   with a small assembly wrapper to force the sz argument to 84 if it is 88
43  *   to avoid copying the extra padding over user space unexpecting it.
44  *
45  * sys_newuname:
46  *
47  *   struct new_utsname has no padding with EABI.  No problem there.
48  *
49  * sys_epoll_ctl:
50  * sys_epoll_wait:
51  *
52  *   struct epoll_event has its second member shifted also affecting the
53  *   structure size. Compatibility wrappers are needed and provided below.
54  *
55  * sys_ipc:
56  * sys_semop:
57  * sys_semtimedop:
58  *
59  *   struct sembuf loses its padding with EABI.  Since arrays of them are
60  *   used they have to be copyed to remove the padding. Compatibility wrappers
61  *   provided below.
62  *
63  * sys_bind:
64  * sys_connect:
65  * sys_sendmsg:
66  * sys_sendto:
67  * sys_socketcall:
68  *
69  *   struct sockaddr_un loses its padding with EABI.  Since the size of the
70  *   structure is used as a validation test in unix_mkname(), we need to
71  *   change the length argument to 110 whenever it is 112.  Compatibility
72  *   wrappers provided below.
73  */
74 
75 #include <linux/syscalls.h>
76 #include <linux/errno.h>
77 #include <linux/fs.h>
78 #include <linux/filelock.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/ipc_namespace.h>
87 #include <linux/uaccess.h>
88 #include <linux/slab.h>
89 
90 #include <asm/syscall.h>
91 
92 struct oldabi_stat64 {
93 	unsigned long long st_dev;
94 	unsigned int	__pad1;
95 	unsigned long	__st_ino;
96 	unsigned int	st_mode;
97 	unsigned int	st_nlink;
98 
99 	unsigned long	st_uid;
100 	unsigned long	st_gid;
101 
102 	unsigned long long st_rdev;
103 	unsigned int	__pad2;
104 
105 	long long	st_size;
106 	unsigned long	st_blksize;
107 	unsigned long long st_blocks;
108 
109 	unsigned long	st_atime;
110 	unsigned long	st_atime_nsec;
111 
112 	unsigned long	st_mtime;
113 	unsigned long	st_mtime_nsec;
114 
115 	unsigned long	st_ctime;
116 	unsigned long	st_ctime_nsec;
117 
118 	unsigned long long st_ino;
119 } __attribute__ ((packed,aligned(4)));
120 
121 static long cp_oldabi_stat64(struct kstat *stat,
122 			     struct oldabi_stat64 __user *statbuf)
123 {
124 	struct oldabi_stat64 tmp;
125 
126 	tmp.st_dev = huge_encode_dev(stat->dev);
127 	tmp.__pad1 = 0;
128 	tmp.__st_ino = stat->ino;
129 	tmp.st_mode = stat->mode;
130 	tmp.st_nlink = stat->nlink;
131 	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
132 	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
133 	tmp.st_rdev = huge_encode_dev(stat->rdev);
134 	tmp.st_size = stat->size;
135 	tmp.st_blocks = stat->blocks;
136 	tmp.__pad2 = 0;
137 	tmp.st_blksize = stat->blksize;
138 	tmp.st_atime = stat->atime.tv_sec;
139 	tmp.st_atime_nsec = stat->atime.tv_nsec;
140 	tmp.st_mtime = stat->mtime.tv_sec;
141 	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
142 	tmp.st_ctime = stat->ctime.tv_sec;
143 	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
144 	tmp.st_ino = stat->ino;
145 	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
146 }
147 
148 asmlinkage long sys_oabi_stat64(const char __user * filename,
149 				struct oldabi_stat64 __user * statbuf)
150 {
151 	struct kstat stat;
152 	int error = vfs_stat(filename, &stat);
153 	if (!error)
154 		error = cp_oldabi_stat64(&stat, statbuf);
155 	return error;
156 }
157 
158 asmlinkage long sys_oabi_lstat64(const char __user * filename,
159 				 struct oldabi_stat64 __user * statbuf)
160 {
161 	struct kstat stat;
162 	int error = vfs_lstat(filename, &stat);
163 	if (!error)
164 		error = cp_oldabi_stat64(&stat, statbuf);
165 	return error;
166 }
167 
168 asmlinkage long sys_oabi_fstat64(unsigned long fd,
169 				 struct oldabi_stat64 __user * statbuf)
170 {
171 	struct kstat stat;
172 	int error = vfs_fstat(fd, &stat);
173 	if (!error)
174 		error = cp_oldabi_stat64(&stat, statbuf);
175 	return error;
176 }
177 
178 asmlinkage long sys_oabi_fstatat64(int dfd,
179 				   const char __user *filename,
180 				   struct oldabi_stat64  __user *statbuf,
181 				   int flag)
182 {
183 	struct kstat stat;
184 	int error;
185 
186 	error = vfs_fstatat(dfd, filename, &stat, flag);
187 	if (error)
188 		return error;
189 	return cp_oldabi_stat64(&stat, statbuf);
190 }
191 
192 struct oabi_flock64 {
193 	short	l_type;
194 	short	l_whence;
195 	loff_t	l_start;
196 	loff_t	l_len;
197 	pid_t	l_pid;
198 } __attribute__ ((packed,aligned(4)));
199 
200 static int get_oabi_flock(struct flock64 *kernel, struct oabi_flock64 __user *arg)
201 {
202 	struct oabi_flock64 user;
203 
204 	if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
205 			   sizeof(user)))
206 		return -EFAULT;
207 
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 	return 0;
215 }
216 
217 static int put_oabi_flock(struct flock64 *kernel, struct oabi_flock64 __user *arg)
218 {
219 	struct oabi_flock64 user;
220 
221 	user.l_type	= kernel->l_type;
222 	user.l_whence	= kernel->l_whence;
223 	user.l_start	= kernel->l_start;
224 	user.l_len	= kernel->l_len;
225 	user.l_pid	= kernel->l_pid;
226 
227 	if (copy_to_user((struct oabi_flock64 __user *)arg,
228 			 &user, sizeof(user)))
229 		return -EFAULT;
230 
231 	return 0;
232 }
233 
234 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
235 				 unsigned long arg)
236 {
237 	void __user *argp = (void __user *)arg;
238 	struct fd f = fdget_raw(fd);
239 	struct flock64 flock;
240 	long err = -EBADF;
241 
242 	if (!fd_file(f))
243 		goto out;
244 
245 	switch (cmd) {
246 	case F_GETLK64:
247 	case F_OFD_GETLK:
248 		err = security_file_fcntl(fd_file(f), cmd, arg);
249 		if (err)
250 			break;
251 		err = get_oabi_flock(&flock, argp);
252 		if (err)
253 			break;
254 		err = fcntl_getlk64(fd_file(f), cmd, &flock);
255 		if (!err)
256 		       err = put_oabi_flock(&flock, argp);
257 		break;
258 	case F_SETLK64:
259 	case F_SETLKW64:
260 	case F_OFD_SETLK:
261 	case F_OFD_SETLKW:
262 		err = security_file_fcntl(fd_file(f), cmd, arg);
263 		if (err)
264 			break;
265 		err = get_oabi_flock(&flock, argp);
266 		if (err)
267 			break;
268 		err = fcntl_setlk64(fd, fd_file(f), cmd, &flock);
269 		break;
270 	default:
271 		err = sys_fcntl64(fd, cmd, arg);
272 		break;
273 	}
274 	fdput(f);
275 out:
276 	return err;
277 }
278 
279 struct oabi_epoll_event {
280 	__poll_t events;
281 	__u64 data;
282 } __attribute__ ((packed,aligned(4)));
283 
284 #ifdef CONFIG_EPOLL
285 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
286 				   struct oabi_epoll_event __user *event)
287 {
288 	struct oabi_epoll_event user;
289 	struct epoll_event kernel;
290 
291 	if (ep_op_has_event(op) &&
292 	    copy_from_user(&user, event, sizeof(user)))
293 		return -EFAULT;
294 
295 	kernel.events = user.events;
296 	kernel.data   = user.data;
297 
298 	return do_epoll_ctl(epfd, op, fd, &kernel, false);
299 }
300 #else
301 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
302 				   struct oabi_epoll_event __user *event)
303 {
304 	return -EINVAL;
305 }
306 #endif
307 
308 struct epoll_event __user *
309 epoll_put_uevent(__poll_t revents, __u64 data,
310 		 struct epoll_event __user *uevent)
311 {
312 	if (in_oabi_syscall()) {
313 		struct oabi_epoll_event __user *oevent = (void __user *)uevent;
314 
315 		if (__put_user(revents, &oevent->events) ||
316 		    __put_user(data, &oevent->data))
317 			return NULL;
318 
319 		return (void __user *)(oevent+1);
320 	}
321 
322 	if (__put_user(revents, &uevent->events) ||
323 	    __put_user(data, &uevent->data))
324 		return NULL;
325 
326 	return uevent+1;
327 }
328 
329 struct oabi_sembuf {
330 	unsigned short	sem_num;
331 	short		sem_op;
332 	short		sem_flg;
333 	unsigned short	__pad;
334 };
335 
336 #define sc_semopm     sem_ctls[2]
337 
338 #ifdef CONFIG_SYSVIPC
339 asmlinkage long sys_oabi_semtimedop(int semid,
340 				    struct oabi_sembuf __user *tsops,
341 				    unsigned nsops,
342 				    const struct old_timespec32 __user *timeout)
343 {
344 	struct ipc_namespace *ns;
345 	struct sembuf *sops;
346 	long err;
347 	int i;
348 
349 	ns = current->nsproxy->ipc_ns;
350 	if (nsops > ns->sc_semopm)
351 		return -E2BIG;
352 	if (nsops < 1 || nsops > SEMOPM)
353 		return -EINVAL;
354 	sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
355 	if (!sops)
356 		return -ENOMEM;
357 	err = 0;
358 	for (i = 0; i < nsops; i++) {
359 		struct oabi_sembuf osb;
360 		err |= copy_from_user(&osb, tsops, sizeof(osb));
361 		sops[i].sem_num = osb.sem_num;
362 		sops[i].sem_op = osb.sem_op;
363 		sops[i].sem_flg = osb.sem_flg;
364 		tsops++;
365 	}
366 	if (err) {
367 		err = -EFAULT;
368 		goto out;
369 	}
370 
371 	if (timeout) {
372 		struct timespec64 ts;
373 		err = get_old_timespec32(&ts, timeout);
374 		if (err)
375 			goto out;
376 		err = __do_semtimedop(semid, sops, nsops, &ts, ns);
377 		goto out;
378 	}
379 	err = __do_semtimedop(semid, sops, nsops, NULL, ns);
380 out:
381 	kvfree(sops);
382 	return err;
383 }
384 
385 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
386 			       unsigned nsops)
387 {
388 	return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
389 }
390 
391 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
392 			    void __user *ptr, long fifth)
393 {
394 	switch (call & 0xffff) {
395 	case SEMOP:
396 		return  sys_oabi_semtimedop(first,
397 					    (struct oabi_sembuf __user *)ptr,
398 					    second, NULL);
399 	case SEMTIMEDOP:
400 		return  sys_oabi_semtimedop(first,
401 					    (struct oabi_sembuf __user *)ptr,
402 					    second,
403 					    (const struct old_timespec32 __user *)fifth);
404 	default:
405 		return sys_ipc(call, first, second, third, ptr, fifth);
406 	}
407 }
408 #else
409 asmlinkage long sys_oabi_semtimedop(int semid,
410 				    struct oabi_sembuf __user *tsops,
411 				    unsigned nsops,
412 				    const struct old_timespec32 __user *timeout)
413 {
414 	return -ENOSYS;
415 }
416 
417 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
418 			       unsigned nsops)
419 {
420 	return -ENOSYS;
421 }
422 
423 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
424 			    void __user *ptr, long fifth)
425 {
426 	return -ENOSYS;
427 }
428 #endif
429 
430 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
431 {
432 	sa_family_t sa_family;
433 	if (addrlen == 112 &&
434 	    get_user(sa_family, &addr->sa_family) == 0 &&
435 	    sa_family == AF_UNIX)
436 			addrlen = 110;
437 	return sys_bind(fd, addr, addrlen);
438 }
439 
440 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
441 {
442 	sa_family_t sa_family;
443 	if (addrlen == 112 &&
444 	    get_user(sa_family, &addr->sa_family) == 0 &&
445 	    sa_family == AF_UNIX)
446 			addrlen = 110;
447 	return sys_connect(fd, addr, addrlen);
448 }
449 
450 asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
451 				size_t len, unsigned flags,
452 				struct sockaddr __user *addr,
453 				int addrlen)
454 {
455 	sa_family_t sa_family;
456 	if (addrlen == 112 &&
457 	    get_user(sa_family, &addr->sa_family) == 0 &&
458 	    sa_family == AF_UNIX)
459 			addrlen = 110;
460 	return sys_sendto(fd, buff, len, flags, addr, addrlen);
461 }
462 
463 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags)
464 {
465 	struct sockaddr __user *addr;
466 	int msg_namelen;
467 	sa_family_t sa_family;
468 	if (msg &&
469 	    get_user(msg_namelen, &msg->msg_namelen) == 0 &&
470 	    msg_namelen == 112 &&
471 	    get_user(addr, &msg->msg_name) == 0 &&
472 	    get_user(sa_family, &addr->sa_family) == 0 &&
473 	    sa_family == AF_UNIX)
474 	{
475 		/*
476 		 * HACK ALERT: there is a limit to how much backward bending
477 		 * we should do for what is actually a transitional
478 		 * compatibility layer.  This already has known flaws with
479 		 * a few ioctls that we don't intend to fix.  Therefore
480 		 * consider this blatent hack as another one... and take care
481 		 * to run for cover.  In most cases it will "just work fine".
482 		 * If it doesn't, well, tough.
483 		 */
484 		put_user(110, &msg->msg_namelen);
485 	}
486 	return sys_sendmsg(fd, msg, flags);
487 }
488 
489 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
490 {
491 	unsigned long r = -EFAULT, a[6];
492 
493 	switch (call) {
494 	case SYS_BIND:
495 		if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
496 			r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
497 		break;
498 	case SYS_CONNECT:
499 		if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
500 			r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
501 		break;
502 	case SYS_SENDTO:
503 		if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
504 			r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
505 					    (struct sockaddr __user *)a[4], a[5]);
506 		break;
507 	case SYS_SENDMSG:
508 		if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
509 			r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]);
510 		break;
511 	default:
512 		r = sys_socketcall(call, args);
513 	}
514 
515 	return r;
516 }
517