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 (!f.file)
243 goto out;
244
245 switch (cmd) {
246 case F_GETLK64:
247 case F_OFD_GETLK:
248 err = security_file_fcntl(f.file, cmd, arg);
249 if (err)
250 break;
251 err = get_oabi_flock(&flock, argp);
252 if (err)
253 break;
254 err = fcntl_getlk64(f.file, 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(f.file, cmd, arg);
263 if (err)
264 break;
265 err = get_oabi_flock(&flock, argp);
266 if (err)
267 break;
268 err = fcntl_setlk64(fd, f.file, 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
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.