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 /*
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.
19  *
20  * The following syscalls are affected:
21  *
22  * sys_stat64:
23  * sys_lstat64:
24  * sys_fstat64:
25  * sys_fstatat64:
26  *
27  *   struct stat64 has different sizes and some members are shifted
28  *   Compatibility wrappers are needed for them and provided below.
29  *
30  * sys_fcntl64:
31  *
32  *   struct flock64 has different sizes and some members are shifted
33  *   A compatibility wrapper is needed and provided below.
34  *
35  * sys_statfs64:
36  * sys_fstatfs64:
37  *
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.
42  *
43  * sys_newuname:
44  *
45  *   struct new_utsname has no padding with EABI.  No problem there.
46  *
47  * sys_epoll_ctl:
48  * sys_epoll_wait:
49  *
50  *   struct epoll_event has its second member shifted also affecting the
51  *   structure size. Compatibility wrappers are needed and provided below.
52  *
53  * sys_ipc:
54  * sys_semop:
55  * sys_semtimedop:
56  *
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
59  *   provided below.
60  *
61  * sys_bind:
62  * sys_connect:
63  * sys_sendmsg:
64  * sys_sendto:
65  * sys_socketcall:
66  *
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.
71  */
72 
73 #include <linux/syscalls.h>
74 #include <linux/errno.h>
75 #include <linux/fs.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/ipc_namespace.h>
84 #include <linux/uaccess.h>
85 #include <linux/slab.h>
86 
87 #include <asm/syscall.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 
cp_oldabi_stat64(struct kstat * stat,struct oldabi_stat64 __user * statbuf)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 
sys_oabi_stat64(const char __user * filename,struct oldabi_stat64 __user * statbuf)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 
sys_oabi_lstat64(const char __user * filename,struct oldabi_stat64 __user * statbuf)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 
sys_oabi_fstat64(unsigned long fd,struct oldabi_stat64 __user * statbuf)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 
sys_oabi_fstatat64(int dfd,const char __user * filename,struct oldabi_stat64 __user * statbuf,int flag)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 
get_oabi_flock(struct flock64 * kernel,struct oabi_flock64 __user * arg)197 static int get_oabi_flock(struct flock64 *kernel, struct oabi_flock64 __user *arg)
198 {
199 	struct oabi_flock64 user;
200 
201 	if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
202 			   sizeof(user)))
203 		return -EFAULT;
204 
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;
210 
211 	return 0;
212 }
213 
put_oabi_flock(struct flock64 * kernel,struct oabi_flock64 __user * arg)214 static int put_oabi_flock(struct flock64 *kernel, struct oabi_flock64 __user *arg)
215 {
216 	struct oabi_flock64 user;
217 
218 	user.l_type	= kernel->l_type;
219 	user.l_whence	= kernel->l_whence;
220 	user.l_start	= kernel->l_start;
221 	user.l_len	= kernel->l_len;
222 	user.l_pid	= kernel->l_pid;
223 
224 	if (copy_to_user((struct oabi_flock64 __user *)arg,
225 			 &user, sizeof(user)))
226 		return -EFAULT;
227 
228 	return 0;
229 }
230 
sys_oabi_fcntl64(unsigned int fd,unsigned int cmd,unsigned long arg)231 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
232 				 unsigned long arg)
233 {
234 	void __user *argp = (void __user *)arg;
235 	struct fd f = fdget_raw(fd);
236 	struct flock64 flock;
237 	long err = -EBADF;
238 
239 	if (!f.file)
240 		goto out;
241 
242 	switch (cmd) {
243 	case F_GETLK64:
244 	case F_OFD_GETLK:
245 		err = security_file_fcntl(f.file, cmd, arg);
246 		if (err)
247 			break;
248 		err = get_oabi_flock(&flock, argp);
249 		if (err)
250 			break;
251 		err = fcntl_getlk64(f.file, cmd, &flock);
252 		if (!err)
253 		       err = put_oabi_flock(&flock, argp);
254 		break;
255 	case F_SETLK64:
256 	case F_SETLKW64:
257 	case F_OFD_SETLK:
258 	case F_OFD_SETLKW:
259 		err = security_file_fcntl(f.file, cmd, arg);
260 		if (err)
261 			break;
262 		err = get_oabi_flock(&flock, argp);
263 		if (err)
264 			break;
265 		err = fcntl_setlk64(fd, f.file, cmd, &flock);
266 		break;
267 	default:
268 		err = sys_fcntl64(fd, cmd, arg);
269 		break;
270 	}
271 	fdput(f);
272 out:
273 	return err;
274 }
275 
276 struct oabi_epoll_event {
277 	__poll_t events;
278 	__u64 data;
279 } __attribute__ ((packed,aligned(4)));
280 
281 #ifdef CONFIG_EPOLL
sys_oabi_epoll_ctl(int epfd,int op,int fd,struct oabi_epoll_event __user * event)282 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
283 				   struct oabi_epoll_event __user *event)
284 {
285 	struct oabi_epoll_event user;
286 	struct epoll_event kernel;
287 
288 	if (ep_op_has_event(op) &&
289 	    copy_from_user(&user, event, sizeof(user)))
290 		return -EFAULT;
291 
292 	kernel.events = user.events;
293 	kernel.data   = user.data;
294 
295 	return do_epoll_ctl(epfd, op, fd, &kernel, false);
296 }
297 #else
sys_oabi_epoll_ctl(int epfd,int op,int fd,struct oabi_epoll_event __user * event)298 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
299 				   struct oabi_epoll_event __user *event)
300 {
301 	return -EINVAL;
302 }
303 #endif
304 
305 struct epoll_event __user *
epoll_put_uevent(__poll_t revents,__u64 data,struct epoll_event __user * uevent)306 epoll_put_uevent(__poll_t revents, __u64 data,
307 		 struct epoll_event __user *uevent)
308 {
309 	if (in_oabi_syscall()) {
310 		struct oabi_epoll_event __user *oevent = (void __user *)uevent;
311 
312 		if (__put_user(revents, &oevent->events) ||
313 		    __put_user(data, &oevent->data))
314 			return NULL;
315 
316 		return (void __user *)(oevent+1);
317 	}
318 
319 	if (__put_user(revents, &uevent->events) ||
320 	    __put_user(data, &uevent->data))
321 		return NULL;
322 
323 	return uevent+1;
324 }
325 
326 struct oabi_sembuf {
327 	unsigned short	sem_num;
328 	short		sem_op;
329 	short		sem_flg;
330 	unsigned short	__pad;
331 };
332 
333 #define sc_semopm     sem_ctls[2]
334 
335 #ifdef CONFIG_SYSVIPC
sys_oabi_semtimedop(int semid,struct oabi_sembuf __user * tsops,unsigned nsops,const struct old_timespec32 __user * timeout)336 asmlinkage long sys_oabi_semtimedop(int semid,
337 				    struct oabi_sembuf __user *tsops,
338 				    unsigned nsops,
339 				    const struct old_timespec32 __user *timeout)
340 {
341 	struct ipc_namespace *ns;
342 	struct sembuf *sops;
343 	long err;
344 	int i;
345 
346 	ns = current->nsproxy->ipc_ns;
347 	if (nsops > ns->sc_semopm)
348 		return -E2BIG;
349 	if (nsops < 1 || nsops > SEMOPM)
350 		return -EINVAL;
351 	sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
352 	if (!sops)
353 		return -ENOMEM;
354 	err = 0;
355 	for (i = 0; i < nsops; i++) {
356 		struct oabi_sembuf osb;
357 		err |= copy_from_user(&osb, tsops, sizeof(osb));
358 		sops[i].sem_num = osb.sem_num;
359 		sops[i].sem_op = osb.sem_op;
360 		sops[i].sem_flg = osb.sem_flg;
361 		tsops++;
362 	}
363 	if (err) {
364 		err = -EFAULT;
365 		goto out;
366 	}
367 
368 	if (timeout) {
369 		struct timespec64 ts;
370 		err = get_old_timespec32(&ts, timeout);
371 		if (err)
372 			goto out;
373 		err = __do_semtimedop(semid, sops, nsops, &ts, ns);
374 		goto out;
375 	}
376 	err = __do_semtimedop(semid, sops, nsops, NULL, ns);
377 out:
378 	kvfree(sops);
379 	return err;
380 }
381 
sys_oabi_semop(int semid,struct oabi_sembuf __user * tsops,unsigned nsops)382 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
383 			       unsigned nsops)
384 {
385 	return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
386 }
387 
sys_oabi_ipc(uint call,int first,int second,int third,void __user * ptr,long fifth)388 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
389 			    void __user *ptr, long fifth)
390 {
391 	switch (call & 0xffff) {
392 	case SEMOP:
393 		return  sys_oabi_semtimedop(first,
394 					    (struct oabi_sembuf __user *)ptr,
395 					    second, NULL);
396 	case SEMTIMEDOP:
397 		return  sys_oabi_semtimedop(first,
398 					    (struct oabi_sembuf __user *)ptr,
399 					    second,
400 					    (const struct old_timespec32 __user *)fifth);
401 	default:
402 		return sys_ipc(call, first, second, third, ptr, fifth);
403 	}
404 }
405 #else
sys_oabi_semtimedop(int semid,struct oabi_sembuf __user * tsops,unsigned nsops,const struct old_timespec32 __user * timeout)406 asmlinkage long sys_oabi_semtimedop(int semid,
407 				    struct oabi_sembuf __user *tsops,
408 				    unsigned nsops,
409 				    const struct old_timespec32 __user *timeout)
410 {
411 	return -ENOSYS;
412 }
413 
sys_oabi_semop(int semid,struct oabi_sembuf __user * tsops,unsigned nsops)414 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
415 			       unsigned nsops)
416 {
417 	return -ENOSYS;
418 }
419 
sys_oabi_ipc(uint call,int first,int second,int third,void __user * ptr,long fifth)420 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
421 			    void __user *ptr, long fifth)
422 {
423 	return -ENOSYS;
424 }
425 #endif
426 
sys_oabi_bind(int fd,struct sockaddr __user * addr,int addrlen)427 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
428 {
429 	sa_family_t sa_family;
430 	if (addrlen == 112 &&
431 	    get_user(sa_family, &addr->sa_family) == 0 &&
432 	    sa_family == AF_UNIX)
433 			addrlen = 110;
434 	return sys_bind(fd, addr, addrlen);
435 }
436 
sys_oabi_connect(int fd,struct sockaddr __user * addr,int addrlen)437 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
438 {
439 	sa_family_t sa_family;
440 	if (addrlen == 112 &&
441 	    get_user(sa_family, &addr->sa_family) == 0 &&
442 	    sa_family == AF_UNIX)
443 			addrlen = 110;
444 	return sys_connect(fd, addr, addrlen);
445 }
446 
sys_oabi_sendto(int fd,void __user * buff,size_t len,unsigned flags,struct sockaddr __user * addr,int addrlen)447 asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
448 				size_t len, unsigned flags,
449 				struct sockaddr __user *addr,
450 				int addrlen)
451 {
452 	sa_family_t sa_family;
453 	if (addrlen == 112 &&
454 	    get_user(sa_family, &addr->sa_family) == 0 &&
455 	    sa_family == AF_UNIX)
456 			addrlen = 110;
457 	return sys_sendto(fd, buff, len, flags, addr, addrlen);
458 }
459 
sys_oabi_sendmsg(int fd,struct user_msghdr __user * msg,unsigned flags)460 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags)
461 {
462 	struct sockaddr __user *addr;
463 	int msg_namelen;
464 	sa_family_t sa_family;
465 	if (msg &&
466 	    get_user(msg_namelen, &msg->msg_namelen) == 0 &&
467 	    msg_namelen == 112 &&
468 	    get_user(addr, &msg->msg_name) == 0 &&
469 	    get_user(sa_family, &addr->sa_family) == 0 &&
470 	    sa_family == AF_UNIX)
471 	{
472 		/*
473 		 * HACK ALERT: there is a limit to how much backward bending
474 		 * we should do for what is actually a transitional
475 		 * compatibility layer.  This already has known flaws with
476 		 * a few ioctls that we don't intend to fix.  Therefore
477 		 * consider this blatent hack as another one... and take care
478 		 * to run for cover.  In most cases it will "just work fine".
479 		 * If it doesn't, well, tough.
480 		 */
481 		put_user(110, &msg->msg_namelen);
482 	}
483 	return sys_sendmsg(fd, msg, flags);
484 }
485 
sys_oabi_socketcall(int call,unsigned long __user * args)486 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
487 {
488 	unsigned long r = -EFAULT, a[6];
489 
490 	switch (call) {
491 	case SYS_BIND:
492 		if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
493 			r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
494 		break;
495 	case SYS_CONNECT:
496 		if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
497 			r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
498 		break;
499 	case SYS_SENDTO:
500 		if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
501 			r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
502 					    (struct sockaddr __user *)a[4], a[5]);
503 		break;
504 	case SYS_SENDMSG:
505 		if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
506 			r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]);
507 		break;
508 	default:
509 		r = sys_socketcall(call, args);
510 	}
511 
512 	return r;
513 }
514