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
cp_oldabi_stat64(struct kstat * stat,struct oldabi_stat64 __user * statbuf)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
sys_oabi_stat64(const char __user * filename,struct oldabi_stat64 __user * statbuf)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
sys_oabi_lstat64(const char __user * filename,struct oldabi_stat64 __user * statbuf)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
sys_oabi_fstat64(unsigned long fd,struct oldabi_stat64 __user * statbuf)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
sys_oabi_fstatat64(int dfd,const char __user * filename,struct oldabi_stat64 __user * statbuf,int flag)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
get_oabi_flock(struct flock64 * kernel,struct oabi_flock64 __user * arg)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
put_oabi_flock(struct flock64 * kernel,struct oabi_flock64 __user * arg)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
sys_oabi_fcntl64(unsigned int fd,unsigned int cmd,unsigned long arg)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 CLASS(fd_raw, f)(fd);
239 struct flock64 flock;
240 long err;
241
242 if (fd_empty(f))
243 return -EBADF;
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 return err;
275 }
276
277 struct oabi_epoll_event {
278 __poll_t events;
279 __u64 data;
280 } __attribute__ ((packed,aligned(4)));
281
282 #ifdef CONFIG_EPOLL
sys_oabi_epoll_ctl(int epfd,int op,int fd,struct oabi_epoll_event __user * event)283 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
284 struct oabi_epoll_event __user *event)
285 {
286 struct oabi_epoll_event user;
287 struct epoll_event kernel;
288
289 if (ep_op_has_event(op) &&
290 copy_from_user(&user, event, sizeof(user)))
291 return -EFAULT;
292
293 kernel.events = user.events;
294 kernel.data = user.data;
295
296 return do_epoll_ctl(epfd, op, fd, &kernel, false);
297 }
298 #else
sys_oabi_epoll_ctl(int epfd,int op,int fd,struct oabi_epoll_event __user * event)299 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
300 struct oabi_epoll_event __user *event)
301 {
302 return -EINVAL;
303 }
304 #endif
305
306 struct epoll_event __user *
epoll_put_uevent(__poll_t revents,__u64 data,struct epoll_event __user * uevent)307 epoll_put_uevent(__poll_t revents, __u64 data,
308 struct epoll_event __user *uevent)
309 {
310 if (in_oabi_syscall()) {
311 struct oabi_epoll_event __user *oevent = (void __user *)uevent;
312
313 if (__put_user(revents, &oevent->events) ||
314 __put_user(data, &oevent->data))
315 return NULL;
316
317 return (void __user *)(oevent+1);
318 }
319
320 if (__put_user(revents, &uevent->events) ||
321 __put_user(data, &uevent->data))
322 return NULL;
323
324 return uevent+1;
325 }
326
327 struct oabi_sembuf {
328 unsigned short sem_num;
329 short sem_op;
330 short sem_flg;
331 unsigned short __pad;
332 };
333
334 #define sc_semopm sem_ctls[2]
335
336 #ifdef CONFIG_SYSVIPC
sys_oabi_semtimedop(int semid,struct oabi_sembuf __user * tsops,unsigned nsops,const struct old_timespec32 __user * timeout)337 asmlinkage long sys_oabi_semtimedop(int semid,
338 struct oabi_sembuf __user *tsops,
339 unsigned nsops,
340 const struct old_timespec32 __user *timeout)
341 {
342 struct ipc_namespace *ns;
343 struct sembuf *sops;
344 long err;
345 int i;
346
347 ns = current->nsproxy->ipc_ns;
348 if (nsops > ns->sc_semopm)
349 return -E2BIG;
350 if (nsops < 1 || nsops > SEMOPM)
351 return -EINVAL;
352 sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
353 if (!sops)
354 return -ENOMEM;
355 err = 0;
356 for (i = 0; i < nsops; i++) {
357 struct oabi_sembuf osb;
358 err |= copy_from_user(&osb, tsops, sizeof(osb));
359 sops[i].sem_num = osb.sem_num;
360 sops[i].sem_op = osb.sem_op;
361 sops[i].sem_flg = osb.sem_flg;
362 tsops++;
363 }
364 if (err) {
365 err = -EFAULT;
366 goto out;
367 }
368
369 if (timeout) {
370 struct timespec64 ts;
371 err = get_old_timespec32(&ts, timeout);
372 if (err)
373 goto out;
374 err = __do_semtimedop(semid, sops, nsops, &ts, ns);
375 goto out;
376 }
377 err = __do_semtimedop(semid, sops, nsops, NULL, ns);
378 out:
379 kvfree(sops);
380 return err;
381 }
382
sys_oabi_semop(int semid,struct oabi_sembuf __user * tsops,unsigned nsops)383 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
384 unsigned nsops)
385 {
386 return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
387 }
388
sys_oabi_ipc(uint call,int first,int second,int third,void __user * ptr,long fifth)389 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
390 void __user *ptr, long fifth)
391 {
392 switch (call & 0xffff) {
393 case SEMOP:
394 return sys_oabi_semtimedop(first,
395 (struct oabi_sembuf __user *)ptr,
396 second, NULL);
397 case SEMTIMEDOP:
398 return sys_oabi_semtimedop(first,
399 (struct oabi_sembuf __user *)ptr,
400 second,
401 (const struct old_timespec32 __user *)fifth);
402 default:
403 return sys_ipc(call, first, second, third, ptr, fifth);
404 }
405 }
406 #else
sys_oabi_semtimedop(int semid,struct oabi_sembuf __user * tsops,unsigned nsops,const struct old_timespec32 __user * timeout)407 asmlinkage long sys_oabi_semtimedop(int semid,
408 struct oabi_sembuf __user *tsops,
409 unsigned nsops,
410 const struct old_timespec32 __user *timeout)
411 {
412 return -ENOSYS;
413 }
414
sys_oabi_semop(int semid,struct oabi_sembuf __user * tsops,unsigned nsops)415 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
416 unsigned nsops)
417 {
418 return -ENOSYS;
419 }
420
sys_oabi_ipc(uint call,int first,int second,int third,void __user * ptr,long fifth)421 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
422 void __user *ptr, long fifth)
423 {
424 return -ENOSYS;
425 }
426 #endif
427
sys_oabi_bind(int fd,struct sockaddr __user * addr,int addrlen)428 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
429 {
430 sa_family_t sa_family;
431 if (addrlen == 112 &&
432 get_user(sa_family, &addr->sa_family) == 0 &&
433 sa_family == AF_UNIX)
434 addrlen = 110;
435 return sys_bind(fd, addr, addrlen);
436 }
437
sys_oabi_connect(int fd,struct sockaddr __user * addr,int addrlen)438 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
439 {
440 sa_family_t sa_family;
441 if (addrlen == 112 &&
442 get_user(sa_family, &addr->sa_family) == 0 &&
443 sa_family == AF_UNIX)
444 addrlen = 110;
445 return sys_connect(fd, addr, addrlen);
446 }
447
sys_oabi_sendto(int fd,void __user * buff,size_t len,unsigned flags,struct sockaddr __user * addr,int addrlen)448 asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
449 size_t len, unsigned flags,
450 struct sockaddr __user *addr,
451 int addrlen)
452 {
453 sa_family_t sa_family;
454 if (addrlen == 112 &&
455 get_user(sa_family, &addr->sa_family) == 0 &&
456 sa_family == AF_UNIX)
457 addrlen = 110;
458 return sys_sendto(fd, buff, len, flags, addr, addrlen);
459 }
460
sys_oabi_sendmsg(int fd,struct user_msghdr __user * msg,unsigned flags)461 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags)
462 {
463 struct sockaddr __user *addr;
464 int msg_namelen;
465 sa_family_t sa_family;
466 if (msg &&
467 get_user(msg_namelen, &msg->msg_namelen) == 0 &&
468 msg_namelen == 112 &&
469 get_user(addr, &msg->msg_name) == 0 &&
470 get_user(sa_family, &addr->sa_family) == 0 &&
471 sa_family == AF_UNIX)
472 {
473 /*
474 * HACK ALERT: there is a limit to how much backward bending
475 * we should do for what is actually a transitional
476 * compatibility layer. This already has known flaws with
477 * a few ioctls that we don't intend to fix. Therefore
478 * consider this blatent hack as another one... and take care
479 * to run for cover. In most cases it will "just work fine".
480 * If it doesn't, well, tough.
481 */
482 put_user(110, &msg->msg_namelen);
483 }
484 return sys_sendmsg(fd, msg, flags);
485 }
486
sys_oabi_socketcall(int call,unsigned long __user * args)487 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
488 {
489 unsigned long r = -EFAULT, a[6];
490
491 switch (call) {
492 case SYS_BIND:
493 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
494 r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
495 break;
496 case SYS_CONNECT:
497 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
498 r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
499 break;
500 case SYS_SENDTO:
501 if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
502 r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
503 (struct sockaddr __user *)a[4], a[5]);
504 break;
505 case SYS_SENDMSG:
506 if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
507 r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]);
508 break;
509 default:
510 r = sys_socketcall(call, args);
511 }
512
513 return r;
514 }
515