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/uaccess.h>
84 #include <linux/slab.h>
85
86 struct oldabi_stat64 {
87 unsigned long long st_dev;
88 unsigned int __pad1;
89 unsigned long __st_ino;
90 unsigned int st_mode;
91 unsigned int st_nlink;
92
93 unsigned long st_uid;
94 unsigned long st_gid;
95
96 unsigned long long st_rdev;
97 unsigned int __pad2;
98
99 long long st_size;
100 unsigned long st_blksize;
101 unsigned long long st_blocks;
102
103 unsigned long st_atime;
104 unsigned long st_atime_nsec;
105
106 unsigned long st_mtime;
107 unsigned long st_mtime_nsec;
108
109 unsigned long st_ctime;
110 unsigned long st_ctime_nsec;
111
112 unsigned long long st_ino;
113 } __attribute__ ((packed,aligned(4)));
114
cp_oldabi_stat64(struct kstat * stat,struct oldabi_stat64 __user * statbuf)115 static long cp_oldabi_stat64(struct kstat *stat,
116 struct oldabi_stat64 __user *statbuf)
117 {
118 struct oldabi_stat64 tmp;
119
120 tmp.st_dev = huge_encode_dev(stat->dev);
121 tmp.__pad1 = 0;
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;
130 tmp.__pad2 = 0;
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;
140 }
141
sys_oabi_stat64(const char __user * filename,struct oldabi_stat64 __user * statbuf)142 asmlinkage long sys_oabi_stat64(const char __user * filename,
143 struct oldabi_stat64 __user * statbuf)
144 {
145 struct kstat stat;
146 int error = vfs_stat(filename, &stat);
147 if (!error)
148 error = cp_oldabi_stat64(&stat, statbuf);
149 return error;
150 }
151
sys_oabi_lstat64(const char __user * filename,struct oldabi_stat64 __user * statbuf)152 asmlinkage long sys_oabi_lstat64(const char __user * filename,
153 struct oldabi_stat64 __user * statbuf)
154 {
155 struct kstat stat;
156 int error = vfs_lstat(filename, &stat);
157 if (!error)
158 error = cp_oldabi_stat64(&stat, statbuf);
159 return error;
160 }
161
sys_oabi_fstat64(unsigned long fd,struct oldabi_stat64 __user * statbuf)162 asmlinkage long sys_oabi_fstat64(unsigned long fd,
163 struct oldabi_stat64 __user * statbuf)
164 {
165 struct kstat stat;
166 int error = vfs_fstat(fd, &stat);
167 if (!error)
168 error = cp_oldabi_stat64(&stat, statbuf);
169 return error;
170 }
171
sys_oabi_fstatat64(int dfd,const char __user * filename,struct oldabi_stat64 __user * statbuf,int flag)172 asmlinkage long sys_oabi_fstatat64(int dfd,
173 const char __user *filename,
174 struct oldabi_stat64 __user *statbuf,
175 int flag)
176 {
177 struct kstat stat;
178 int error;
179
180 error = vfs_fstatat(dfd, filename, &stat, flag);
181 if (error)
182 return error;
183 return cp_oldabi_stat64(&stat, statbuf);
184 }
185
186 struct oabi_flock64 {
187 short l_type;
188 short l_whence;
189 loff_t l_start;
190 loff_t l_len;
191 pid_t l_pid;
192 } __attribute__ ((packed,aligned(4)));
193
do_locks(unsigned int fd,unsigned int cmd,unsigned long arg)194 static long do_locks(unsigned int fd, unsigned int cmd,
195 unsigned long arg)
196 {
197 struct flock64 kernel;
198 struct oabi_flock64 user;
199 mm_segment_t fs;
200 long ret;
201
202 if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
203 sizeof(user)))
204 return -EFAULT;
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 fs = get_fs();
212 set_fs(KERNEL_DS);
213 ret = sys_fcntl64(fd, cmd, (unsigned long)&kernel);
214 set_fs(fs);
215
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)))
224 ret = -EFAULT;
225 }
226 return ret;
227 }
228
sys_oabi_fcntl64(unsigned int fd,unsigned int cmd,unsigned long arg)229 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
230 unsigned long arg)
231 {
232 switch (cmd) {
233 case F_OFD_GETLK:
234 case F_OFD_SETLK:
235 case F_OFD_SETLKW:
236 case F_GETLK64:
237 case F_SETLK64:
238 case F_SETLKW64:
239 return do_locks(fd, cmd, arg);
240
241 default:
242 return sys_fcntl64(fd, cmd, arg);
243 }
244 }
245
246 struct oabi_epoll_event {
247 __u32 events;
248 __u64 data;
249 } __attribute__ ((packed,aligned(4)));
250
sys_oabi_epoll_ctl(int epfd,int op,int fd,struct oabi_epoll_event __user * event)251 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
252 struct oabi_epoll_event __user *event)
253 {
254 struct oabi_epoll_event user;
255 struct epoll_event kernel;
256 mm_segment_t fs;
257 long ret;
258
259 if (op == EPOLL_CTL_DEL)
260 return sys_epoll_ctl(epfd, op, fd, NULL);
261 if (copy_from_user(&user, event, sizeof(user)))
262 return -EFAULT;
263 kernel.events = user.events;
264 kernel.data = user.data;
265 fs = get_fs();
266 set_fs(KERNEL_DS);
267 ret = sys_epoll_ctl(epfd, op, fd, &kernel);
268 set_fs(fs);
269 return ret;
270 }
271
sys_oabi_epoll_wait(int epfd,struct oabi_epoll_event __user * events,int maxevents,int timeout)272 asmlinkage long sys_oabi_epoll_wait(int epfd,
273 struct oabi_epoll_event __user *events,
274 int maxevents, int timeout)
275 {
276 struct epoll_event *kbuf;
277 struct oabi_epoll_event e;
278 mm_segment_t fs;
279 long ret, err, i;
280
281 if (maxevents <= 0 ||
282 maxevents > (INT_MAX/sizeof(*kbuf)) ||
283 maxevents > (INT_MAX/sizeof(*events)))
284 return -EINVAL;
285 if (!access_ok(events, sizeof(*events) * maxevents))
286 return -EFAULT;
287 kbuf = kmalloc_array(maxevents, sizeof(*kbuf), GFP_KERNEL);
288 if (!kbuf)
289 return -ENOMEM;
290 fs = get_fs();
291 set_fs(KERNEL_DS);
292 ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout);
293 set_fs(fs);
294 err = 0;
295 for (i = 0; i < ret; i++) {
296 e.events = kbuf[i].events;
297 e.data = kbuf[i].data;
298 err = __copy_to_user(events, &e, sizeof(e));
299 if (err)
300 break;
301 events++;
302 }
303 kfree(kbuf);
304 return err ? -EFAULT : ret;
305 }
306
307 struct oabi_sembuf {
308 unsigned short sem_num;
309 short sem_op;
310 short sem_flg;
311 unsigned short __pad;
312 };
313
sys_oabi_semtimedop(int semid,struct oabi_sembuf __user * tsops,unsigned nsops,const struct old_timespec32 __user * timeout)314 asmlinkage long sys_oabi_semtimedop(int semid,
315 struct oabi_sembuf __user *tsops,
316 unsigned nsops,
317 const struct old_timespec32 __user *timeout)
318 {
319 struct sembuf *sops;
320 struct old_timespec32 local_timeout;
321 long err;
322 int i;
323
324 if (nsops < 1 || nsops > SEMOPM)
325 return -EINVAL;
326 if (!access_ok(tsops, sizeof(*tsops) * nsops))
327 return -EFAULT;
328 sops = kmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
329 if (!sops)
330 return -ENOMEM;
331 err = 0;
332 for (i = 0; i < nsops; i++) {
333 struct oabi_sembuf osb;
334 err |= __copy_from_user(&osb, tsops, sizeof(osb));
335 sops[i].sem_num = osb.sem_num;
336 sops[i].sem_op = osb.sem_op;
337 sops[i].sem_flg = osb.sem_flg;
338 tsops++;
339 }
340 if (timeout) {
341 /* copy this as well before changing domain protection */
342 err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout));
343 timeout = &local_timeout;
344 }
345 if (err) {
346 err = -EFAULT;
347 } else {
348 mm_segment_t fs = get_fs();
349 set_fs(KERNEL_DS);
350 err = sys_semtimedop_time32(semid, sops, nsops, timeout);
351 set_fs(fs);
352 }
353 kfree(sops);
354 return err;
355 }
356
sys_oabi_semop(int semid,struct oabi_sembuf __user * tsops,unsigned nsops)357 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
358 unsigned nsops)
359 {
360 return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
361 }
362
sys_oabi_ipc(uint call,int first,int second,int third,void __user * ptr,long fifth)363 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
364 void __user *ptr, long fifth)
365 {
366 switch (call & 0xffff) {
367 case SEMOP:
368 return sys_oabi_semtimedop(first,
369 (struct oabi_sembuf __user *)ptr,
370 second, NULL);
371 case SEMTIMEDOP:
372 return sys_oabi_semtimedop(first,
373 (struct oabi_sembuf __user *)ptr,
374 second,
375 (const struct old_timespec32 __user *)fifth);
376 default:
377 return sys_ipc(call, first, second, third, ptr, fifth);
378 }
379 }
380
sys_oabi_bind(int fd,struct sockaddr __user * addr,int addrlen)381 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
382 {
383 sa_family_t sa_family;
384 if (addrlen == 112 &&
385 get_user(sa_family, &addr->sa_family) == 0 &&
386 sa_family == AF_UNIX)
387 addrlen = 110;
388 return sys_bind(fd, addr, addrlen);
389 }
390
sys_oabi_connect(int fd,struct sockaddr __user * addr,int addrlen)391 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
392 {
393 sa_family_t sa_family;
394 if (addrlen == 112 &&
395 get_user(sa_family, &addr->sa_family) == 0 &&
396 sa_family == AF_UNIX)
397 addrlen = 110;
398 return sys_connect(fd, addr, addrlen);
399 }
400
sys_oabi_sendto(int fd,void __user * buff,size_t len,unsigned flags,struct sockaddr __user * addr,int addrlen)401 asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
402 size_t len, unsigned flags,
403 struct sockaddr __user *addr,
404 int addrlen)
405 {
406 sa_family_t sa_family;
407 if (addrlen == 112 &&
408 get_user(sa_family, &addr->sa_family) == 0 &&
409 sa_family == AF_UNIX)
410 addrlen = 110;
411 return sys_sendto(fd, buff, len, flags, addr, addrlen);
412 }
413
sys_oabi_sendmsg(int fd,struct user_msghdr __user * msg,unsigned flags)414 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags)
415 {
416 struct sockaddr __user *addr;
417 int msg_namelen;
418 sa_family_t sa_family;
419 if (msg &&
420 get_user(msg_namelen, &msg->msg_namelen) == 0 &&
421 msg_namelen == 112 &&
422 get_user(addr, &msg->msg_name) == 0 &&
423 get_user(sa_family, &addr->sa_family) == 0 &&
424 sa_family == AF_UNIX)
425 {
426 /*
427 * HACK ALERT: there is a limit to how much backward bending
428 * we should do for what is actually a transitional
429 * compatibility layer. This already has known flaws with
430 * a few ioctls that we don't intend to fix. Therefore
431 * consider this blatent hack as another one... and take care
432 * to run for cover. In most cases it will "just work fine".
433 * If it doesn't, well, tough.
434 */
435 put_user(110, &msg->msg_namelen);
436 }
437 return sys_sendmsg(fd, msg, flags);
438 }
439
sys_oabi_socketcall(int call,unsigned long __user * args)440 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
441 {
442 unsigned long r = -EFAULT, a[6];
443
444 switch (call) {
445 case SYS_BIND:
446 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
447 r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
448 break;
449 case SYS_CONNECT:
450 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
451 r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
452 break;
453 case SYS_SENDTO:
454 if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
455 r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
456 (struct sockaddr __user *)a[4], a[5]);
457 break;
458 case SYS_SENDMSG:
459 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
460 r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]);
461 break;
462 default:
463 r = sys_socketcall(call, args);
464 }
465
466 return r;
467 }
468