summaryrefslogtreecommitdiffstats
path: root/arch/arm/kernel/sys_oabi-compat.c
blob: 1df21a61e379e1a0fe66e784c7a1212814b100da (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
/*
 *  arch/arm/kernel/sys_oabi-compat.c
 *
 *  Compatibility wrappers for syscalls that are used from
 *  old ABI user space binaries with an EABI kernel.
 *
 *  Author:	Nicolas Pitre
 *  Created:	Oct 7, 2005
 *  Copyright:	MontaVista Software, Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 */

/*
 * The legacy ABI and the new ARM EABI have different rules making some
 * syscalls incompatible especially with structure arguments.
 * Most notably, Eabi says 64-bit members should be 64-bit aligned instead of
 * simply word aligned.  EABI also pads structures to the size of the largest
 * member it contains instead of the invariant 32-bit.
 *
 * The following syscalls are affected:
 *
 * sys_stat64:
 * sys_lstat64:
 * sys_fstat64:
 * sys_fstatat64:
 *
 *   struct stat64 has different sizes and some members are shifted
 *   Compatibility wrappers are needed for them and provided below.
 *
 * sys_fcntl64:
 *
 *   struct flock64 has different sizes and some members are shifted
 *   A compatibility wrapper is needed and provided below.
 *
 * sys_statfs64:
 * sys_fstatfs64:
 *
 *   struct statfs64 has extra padding with EABI growing its size from
 *   84 to 88.  This struct is now __attribute__((packed,aligned(4)))
 *   with a small assembly wrapper to force the sz argument to 84 if it is 88
 *   to avoid copying the extra padding over user space unexpecting it.
 *
 * sys_newuname:
 *
 *   struct new_utsname has no padding with EABI.  No problem there.
 *
 * sys_epoll_ctl:
 * sys_epoll_wait:
 *
 *   struct epoll_event has its second member shifted also affecting the
 *   structure size. Compatibility wrappers are needed and provided below.
 *
 * sys_ipc:
 * sys_semop:
 * sys_semtimedop:
 *
 *   struct sembuf loses its padding with EABI.  Since arrays of them are
 *   used they have to be copyed to remove the padding. Compatibility wrappers
 *   provided below.
 *
 * sys_bind:
 * sys_connect:
 * sys_sendmsg:
 * sys_sendto:
 * sys_socketcall:
 *
 *   struct sockaddr_un loses its padding with EABI.  Since the size of the
 *   structure is used as a validation test in unix_mkname(), we need to
 *   change the length argument to 110 whenever it is 112.  Compatibility
 *   wrappers provided below.
 */

#include <linux/syscalls.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/cred.h>
#include <linux/fcntl.h>
#include <linux/eventpoll.h>
#include <linux/sem.h>
#include <linux/socket.h>
#include <linux/net.h>
#include <linux/ipc.h>
#include <linux/uaccess.h>
#include <linux/slab.h>

struct oldabi_stat64 {
	unsigned long long st_dev;
	unsigned int	__pad1;
	unsigned long	__st_ino;
	unsigned int	st_mode;
	unsigned int	st_nlink;

	unsigned long	st_uid;
	unsigned long	st_gid;

	unsigned long long st_rdev;
	unsigned int	__pad2;

	long long	st_size;
	unsigned long	st_blksize;
	unsigned long long st_blocks;

	unsigned long	st_atime;
	unsigned long	st_atime_nsec;

	unsigned long	st_mtime;
	unsigned long	st_mtime_nsec;

	unsigned long	st_ctime;
	unsigned long	st_ctime_nsec;

	unsigned long long st_ino;
} __attribute__ ((packed,aligned(4)));

static long cp_oldabi_stat64(struct kstat *stat,
			     struct oldabi_stat64 __user *statbuf)
{
	struct oldabi_stat64 tmp;

	tmp.st_dev = huge_encode_dev(stat->dev);
	tmp.__pad1 = 0;
	tmp.__st_ino = stat->ino;
	tmp.st_mode = stat->mode;
	tmp.st_nlink = stat->nlink;
	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
	tmp.st_rdev = huge_encode_dev(stat->rdev);
	tmp.st_size = stat->size;
	tmp.st_blocks = stat->blocks;
	tmp.__pad2 = 0;
	tmp.st_blksize = stat->blksize;
	tmp.st_atime = stat->atime.tv_sec;
	tmp.st_atime_nsec = stat->atime.tv_nsec;
	tmp.st_mtime = stat->mtime.tv_sec;
	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
	tmp.st_ctime = stat->ctime.tv_sec;
	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
	tmp.st_ino = stat->ino;
	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}

asmlinkage long sys_oabi_stat64(const char __user * filename,
				struct oldabi_stat64 __user * statbuf)
{
	struct kstat stat;
	int error = vfs_stat(filename, &stat);
	if (!error)
		error = cp_oldabi_stat64(&stat, statbuf);
	return error;
}

asmlinkage long sys_oabi_lstat64(const char __user * filename,
				 struct oldabi_stat64 __user * statbuf)
{
	struct kstat stat;
	int error = vfs_lstat(filename, &stat);
	if (!error)
		error = cp_oldabi_stat64(&stat, statbuf);
	return error;
}

asmlinkage long sys_oabi_fstat64(unsigned long fd,
				 struct oldabi_stat64 __user * statbuf)
{
	struct kstat stat;
	int error = vfs_fstat(fd, &stat);
	if (!error)
		error = cp_oldabi_stat64(&stat, statbuf);
	return error;
}

asmlinkage long sys_oabi_fstatat64(int dfd,
				   const char __user *filename,
				   struct oldabi_stat64  __user *statbuf,
				   int flag)
{
	struct kstat stat;
	int error;

	error = vfs_fstatat(dfd, filename, &stat, flag);
	if (error)
		return error;
	return cp_oldabi_stat64(&stat, statbuf);
}

struct oabi_flock64 {
	short	l_type;
	short	l_whence;
	loff_t	l_start;
	loff_t	l_len;
	pid_t	l_pid;
} __attribute__ ((packed,aligned(4)));

static long do_locks(unsigned int fd, unsigned int cmd,
				 unsigned long arg)
{
	struct flock64 kernel;
	struct oabi_flock64 user;
	mm_segment_t fs;
	long ret;

	if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
			   sizeof(user)))
		return -EFAULT;
	kernel.l_type	= user.l_type;
	kernel.l_whence	= user.l_whence;
	kernel.l_start	= user.l_start;
	kernel.l_len	= user.l_len;
	kernel.l_pid	= user.l_pid;

	fs = get_fs();
	set_fs(KERNEL_DS);
	ret = sys_fcntl64(fd, cmd, (unsigned long)&kernel);
	set_fs(fs);

	if (!ret && (cmd == F_GETLK64 || cmd == F_OFD_GETLK)) {
		user.l_type	= kernel.l_type;
		user.l_whence	= kernel.l_whence;
		user.l_start	= kernel.l_start;
		user.l_len	= kernel.l_len;
		user.l_pid	= kernel.l_pid;
		if (copy_to_user((struct oabi_flock64 __user *)arg,
				 &user, sizeof(user)))
			ret = -EFAULT;
	}
	return ret;
}

asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
				 unsigned long arg)
{
	switch (cmd) {
	case F_OFD_GETLK:
	case F_OFD_SETLK:
	case F_OFD_SETLKW:
	case F_GETLK64:
	case F_SETLK64:
	case F_SETLKW64:
		return do_locks(fd, cmd, arg);

	default:
		return sys_fcntl64(fd, cmd, arg);
	}
}

struct oabi_epoll_event {
	__u32 events;
	__u64 data;
} __attribute__ ((packed,aligned(4)));

asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
				   struct oabi_epoll_event __user *event)
{
	struct oabi_epoll_event user;
	struct epoll_event kernel;
	mm_segment_t fs;
	long ret;

	if (op == EPOLL_CTL_DEL)
		return sys_epoll_ctl(epfd, op, fd, NULL);
	if (copy_from_user(&user, event, sizeof(user)))
		return -EFAULT;
	kernel.events = user.events;
	kernel.data   = user.data;
	fs = get_fs();
	set_fs(KERNEL_DS);
	ret = sys_epoll_ctl(epfd, op, fd, &kernel);
	set_fs(fs);
	return ret;
}

asmlinkage long sys_oabi_epoll_wait(int epfd,
				    struct oabi_epoll_event __user *events,
				    int maxevents, int timeout)
{
	struct epoll_event *kbuf;
	mm_segment_t fs;
	long ret, err, i;

	if (maxevents <= 0 ||
			maxevents > (INT_MAX/sizeof(*kbuf)) ||
			maxevents > (INT_MAX/sizeof(*events)))
		return -EINVAL;
	if (!access_ok(VERIFY_WRITE, events, sizeof(*events) * maxevents))
		return -EFAULT;
	kbuf = kmalloc_array(maxevents, sizeof(*kbuf), GFP_KERNEL);
	if (!kbuf)
		return -ENOMEM;
	fs = get_fs();
	set_fs(KERNEL_DS);
	ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout);
	set_fs(fs);
	err = 0;
	for (i = 0; i < ret; i++) {
		__put_user_error(kbuf[i].events, &events->events, err);
		__put_user_error(kbuf[i].data,   &events->data,   err);
		events++;
	}
	kfree(kbuf);
	return err ? -EFAULT : ret;
}

struct oabi_sembuf {
	unsigned short	sem_num;
	short		sem_op;
	short		sem_flg;
	unsigned short	__pad;
};

asmlinkage long sys_oabi_semtimedop(int semid,
				    struct oabi_sembuf __user *tsops,
				    unsigned nsops,
				    const struct timespec __user *timeout)
{
	struct sembuf *sops;
	struct timespec local_timeout;
	long err;
	int i;

	if (nsops < 1 || nsops > SEMOPM)
		return -EINVAL;
	if (!access_ok(VERIFY_READ, tsops, sizeof(*tsops) * nsops))
		return -EFAULT;
	sops = kmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
	if (!sops)
		return -ENOMEM;
	err = 0;
	for (i = 0; i < nsops; i++) {
		__get_user_error(sops[i].sem_num, &tsops->sem_num, err);
		__get_user_error(sops[i].sem_op,  &tsops->sem_op,  err);
		__get_user_error(sops[i].sem_flg, &tsops->sem_flg, err);
		tsops++;
	}
	if (timeout) {
		/* copy this as well before changing domain protection */
		err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout));
		timeout = &local_timeout;
	}
	if (err) {
		err = -EFAULT;
	} else {
		mm_segment_t fs = get_fs();
		set_fs(KERNEL_DS);
		err = sys_semtimedop(semid, sops, nsops, timeout);
		set_fs(fs);
	}
	kfree(sops);
	return err;
}

asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
			       unsigned nsops)
{
	return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
}

asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
			    void __user *ptr, long fifth)
{
	switch (call & 0xffff) {
	case SEMOP:
		return  sys_oabi_semtimedop(first,
					    (struct oabi_sembuf __user *)ptr,
					    second, NULL);
	case SEMTIMEDOP:
		return  sys_oabi_semtimedop(first,
					    (struct oabi_sembuf __user *)ptr,
					    second,
					    (const struct timespec __user *)fifth);
	default:
		return sys_ipc(call, first, second, third, ptr, fifth);
	}
}

asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
{
	sa_family_t sa_family;
	if (addrlen == 112 &&
	    get_user(sa_family, &addr->sa_family) == 0 &&
	    sa_family == AF_UNIX)
			addrlen = 110;
	return sys_bind(fd, addr, addrlen);
}

asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
{
	sa_family_t sa_family;
	if (addrlen == 112 &&
	    get_user(sa_family, &addr->sa_family) == 0 &&
	    sa_family == AF_UNIX)
			addrlen = 110;
	return sys_connect(fd, addr, addrlen);
}

asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
				size_t len, unsigned flags,
				struct sockaddr __user *addr,
				int addrlen)
{
	sa_family_t sa_family;
	if (addrlen == 112 &&
	    get_user(sa_family, &addr->sa_family) == 0 &&
	    sa_family == AF_UNIX)
			addrlen = 110;
	return sys_sendto(fd, buff, len, flags, addr, addrlen);
}

asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags)
{
	struct sockaddr __user *addr;
	int msg_namelen;
	sa_family_t sa_family;
	if (msg &&
	    get_user(msg_namelen, &msg->msg_namelen) == 0 &&
	    msg_namelen == 112 &&
	    get_user(addr, &msg->msg_name) == 0 &&
	    get_user(sa_family, &addr->sa_family) == 0 &&
	    sa_family == AF_UNIX)
	{
		/*
		 * HACK ALERT: there is a limit to how much backward bending
		 * we should do for what is actually a transitional
		 * compatibility layer.  This already has known flaws with
		 * a few ioctls that we don't intend to fix.  Therefore
		 * consider this blatent hack as another one... and take care
		 * to run for cover.  In most cases it will "just work fine".
		 * If it doesn't, well, tough.
		 */
		put_user(110, &msg->msg_namelen);
	}
	return sys_sendmsg(fd, msg, flags);
}

asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
{
	unsigned long r = -EFAULT, a[6];

	switch (call) {
	case SYS_BIND:
		if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
			r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
		break;
	case SYS_CONNECT:
		if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
			r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
		break;
	case SYS_SENDTO:
		if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
			r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
					    (struct sockaddr __user *)a[4], a[5]);
		break;
	case SYS_SENDMSG:
		if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
			r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]);
		break;
	default:
		r = sys_socketcall(call, args);
	}

	return r;
}