xref: /openbmc/linux/net/compat.c (revision aa0dc6a7) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * 32bit Socket syscall emulation. Based on arch/sparc64/kernel/sys_sparc32.c.
4  *
5  * Copyright (C) 2000		VA Linux Co
6  * Copyright (C) 2000		Don Dugger <n0ano@valinux.com>
7  * Copyright (C) 1999 		Arun Sharma <arun.sharma@intel.com>
8  * Copyright (C) 1997,1998 	Jakub Jelinek (jj@sunsite.mff.cuni.cz)
9  * Copyright (C) 1997 		David S. Miller (davem@caip.rutgers.edu)
10  * Copyright (C) 2000		Hewlett-Packard Co.
11  * Copyright (C) 2000		David Mosberger-Tang <davidm@hpl.hp.com>
12  * Copyright (C) 2000,2001	Andi Kleen, SuSE Labs
13  */
14 
15 #include <linux/kernel.h>
16 #include <linux/gfp.h>
17 #include <linux/fs.h>
18 #include <linux/types.h>
19 #include <linux/file.h>
20 #include <linux/icmpv6.h>
21 #include <linux/socket.h>
22 #include <linux/syscalls.h>
23 #include <linux/filter.h>
24 #include <linux/compat.h>
25 #include <linux/security.h>
26 #include <linux/audit.h>
27 #include <linux/export.h>
28 
29 #include <net/scm.h>
30 #include <net/sock.h>
31 #include <net/ip.h>
32 #include <net/ipv6.h>
33 #include <linux/uaccess.h>
34 #include <net/compat.h>
35 
36 int __get_compat_msghdr(struct msghdr *kmsg,
37 			struct compat_msghdr __user *umsg,
38 			struct sockaddr __user **save_addr,
39 			compat_uptr_t *ptr, compat_size_t *len)
40 {
41 	struct compat_msghdr msg;
42 	ssize_t err;
43 
44 	if (copy_from_user(&msg, umsg, sizeof(*umsg)))
45 		return -EFAULT;
46 
47 	kmsg->msg_flags = msg.msg_flags;
48 	kmsg->msg_namelen = msg.msg_namelen;
49 
50 	if (!msg.msg_name)
51 		kmsg->msg_namelen = 0;
52 
53 	if (kmsg->msg_namelen < 0)
54 		return -EINVAL;
55 
56 	if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))
57 		kmsg->msg_namelen = sizeof(struct sockaddr_storage);
58 
59 	kmsg->msg_control_is_user = true;
60 	kmsg->msg_control_user = compat_ptr(msg.msg_control);
61 	kmsg->msg_controllen = msg.msg_controllen;
62 
63 	if (save_addr)
64 		*save_addr = compat_ptr(msg.msg_name);
65 
66 	if (msg.msg_name && kmsg->msg_namelen) {
67 		if (!save_addr) {
68 			err = move_addr_to_kernel(compat_ptr(msg.msg_name),
69 						  kmsg->msg_namelen,
70 						  kmsg->msg_name);
71 			if (err < 0)
72 				return err;
73 		}
74 	} else {
75 		kmsg->msg_name = NULL;
76 		kmsg->msg_namelen = 0;
77 	}
78 
79 	if (msg.msg_iovlen > UIO_MAXIOV)
80 		return -EMSGSIZE;
81 
82 	kmsg->msg_iocb = NULL;
83 	*ptr = msg.msg_iov;
84 	*len = msg.msg_iovlen;
85 	return 0;
86 }
87 
88 int get_compat_msghdr(struct msghdr *kmsg,
89 		      struct compat_msghdr __user *umsg,
90 		      struct sockaddr __user **save_addr,
91 		      struct iovec **iov)
92 {
93 	compat_uptr_t ptr;
94 	compat_size_t len;
95 	ssize_t err;
96 
97 	err = __get_compat_msghdr(kmsg, umsg, save_addr, &ptr, &len);
98 	if (err)
99 		return err;
100 
101 	err = import_iovec(save_addr ? READ : WRITE, compat_ptr(ptr), len,
102 			   UIO_FASTIOV, iov, &kmsg->msg_iter);
103 	return err < 0 ? err : 0;
104 }
105 
106 /* Bleech... */
107 #define CMSG_COMPAT_ALIGN(len)	ALIGN((len), sizeof(s32))
108 
109 #define CMSG_COMPAT_DATA(cmsg)				\
110 	((void __user *)((char __user *)(cmsg) + sizeof(struct compat_cmsghdr)))
111 #define CMSG_COMPAT_SPACE(len)				\
112 	(sizeof(struct compat_cmsghdr) + CMSG_COMPAT_ALIGN(len))
113 #define CMSG_COMPAT_LEN(len)				\
114 	(sizeof(struct compat_cmsghdr) + (len))
115 
116 #define CMSG_COMPAT_FIRSTHDR(msg)			\
117 	(((msg)->msg_controllen) >= sizeof(struct compat_cmsghdr) ?	\
118 	 (struct compat_cmsghdr __user *)((msg)->msg_control) :		\
119 	 (struct compat_cmsghdr __user *)NULL)
120 
121 #define CMSG_COMPAT_OK(ucmlen, ucmsg, mhdr) \
122 	((ucmlen) >= sizeof(struct compat_cmsghdr) && \
123 	 (ucmlen) <= (unsigned long) \
124 	 ((mhdr)->msg_controllen - \
125 	  ((char __user *)(ucmsg) - (char __user *)(mhdr)->msg_control_user)))
126 
127 static inline struct compat_cmsghdr __user *cmsg_compat_nxthdr(struct msghdr *msg,
128 		struct compat_cmsghdr __user *cmsg, int cmsg_len)
129 {
130 	char __user *ptr = (char __user *)cmsg + CMSG_COMPAT_ALIGN(cmsg_len);
131 	if ((unsigned long)(ptr + 1 - (char __user *)msg->msg_control) >
132 			msg->msg_controllen)
133 		return NULL;
134 	return (struct compat_cmsghdr __user *)ptr;
135 }
136 
137 /* There is a lot of hair here because the alignment rules (and
138  * thus placement) of cmsg headers and length are different for
139  * 32-bit apps.  -DaveM
140  */
141 int cmsghdr_from_user_compat_to_kern(struct msghdr *kmsg, struct sock *sk,
142 			       unsigned char *stackbuf, int stackbuf_size)
143 {
144 	struct compat_cmsghdr __user *ucmsg;
145 	struct cmsghdr *kcmsg, *kcmsg_base;
146 	compat_size_t ucmlen;
147 	__kernel_size_t kcmlen, tmp;
148 	int err = -EFAULT;
149 
150 	BUILD_BUG_ON(sizeof(struct compat_cmsghdr) !=
151 		     CMSG_COMPAT_ALIGN(sizeof(struct compat_cmsghdr)));
152 
153 	kcmlen = 0;
154 	kcmsg_base = kcmsg = (struct cmsghdr *)stackbuf;
155 	ucmsg = CMSG_COMPAT_FIRSTHDR(kmsg);
156 	while (ucmsg != NULL) {
157 		if (get_user(ucmlen, &ucmsg->cmsg_len))
158 			return -EFAULT;
159 
160 		/* Catch bogons. */
161 		if (!CMSG_COMPAT_OK(ucmlen, ucmsg, kmsg))
162 			return -EINVAL;
163 
164 		tmp = ((ucmlen - sizeof(*ucmsg)) + sizeof(struct cmsghdr));
165 		tmp = CMSG_ALIGN(tmp);
166 		kcmlen += tmp;
167 		ucmsg = cmsg_compat_nxthdr(kmsg, ucmsg, ucmlen);
168 	}
169 	if (kcmlen == 0)
170 		return -EINVAL;
171 
172 	/* The kcmlen holds the 64-bit version of the control length.
173 	 * It may not be modified as we do not stick it into the kmsg
174 	 * until we have successfully copied over all of the data
175 	 * from the user.
176 	 */
177 	if (kcmlen > stackbuf_size)
178 		kcmsg_base = kcmsg = sock_kmalloc(sk, kcmlen, GFP_KERNEL);
179 	if (kcmsg == NULL)
180 		return -ENOMEM;
181 
182 	/* Now copy them over neatly. */
183 	memset(kcmsg, 0, kcmlen);
184 	ucmsg = CMSG_COMPAT_FIRSTHDR(kmsg);
185 	while (ucmsg != NULL) {
186 		struct compat_cmsghdr cmsg;
187 		if (copy_from_user(&cmsg, ucmsg, sizeof(cmsg)))
188 			goto Efault;
189 		if (!CMSG_COMPAT_OK(cmsg.cmsg_len, ucmsg, kmsg))
190 			goto Einval;
191 		tmp = ((cmsg.cmsg_len - sizeof(*ucmsg)) + sizeof(struct cmsghdr));
192 		if ((char *)kcmsg_base + kcmlen - (char *)kcmsg < CMSG_ALIGN(tmp))
193 			goto Einval;
194 		kcmsg->cmsg_len = tmp;
195 		kcmsg->cmsg_level = cmsg.cmsg_level;
196 		kcmsg->cmsg_type = cmsg.cmsg_type;
197 		tmp = CMSG_ALIGN(tmp);
198 		if (copy_from_user(CMSG_DATA(kcmsg),
199 				   CMSG_COMPAT_DATA(ucmsg),
200 				   (cmsg.cmsg_len - sizeof(*ucmsg))))
201 			goto Efault;
202 
203 		/* Advance. */
204 		kcmsg = (struct cmsghdr *)((char *)kcmsg + tmp);
205 		ucmsg = cmsg_compat_nxthdr(kmsg, ucmsg, cmsg.cmsg_len);
206 	}
207 
208 	/*
209 	 * check the length of messages copied in is the same as the
210 	 * what we get from the first loop
211 	 */
212 	if ((char *)kcmsg - (char *)kcmsg_base != kcmlen)
213 		goto Einval;
214 
215 	/* Ok, looks like we made it.  Hook it up and return success. */
216 	kmsg->msg_control = kcmsg_base;
217 	kmsg->msg_controllen = kcmlen;
218 	return 0;
219 
220 Einval:
221 	err = -EINVAL;
222 Efault:
223 	if (kcmsg_base != (struct cmsghdr *)stackbuf)
224 		sock_kfree_s(sk, kcmsg_base, kcmlen);
225 	return err;
226 }
227 
228 int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void *data)
229 {
230 	struct compat_cmsghdr __user *cm = (struct compat_cmsghdr __user *) kmsg->msg_control;
231 	struct compat_cmsghdr cmhdr;
232 	struct old_timeval32 ctv;
233 	struct old_timespec32 cts[3];
234 	int cmlen;
235 
236 	if (cm == NULL || kmsg->msg_controllen < sizeof(*cm)) {
237 		kmsg->msg_flags |= MSG_CTRUNC;
238 		return 0; /* XXX: return error? check spec. */
239 	}
240 
241 	if (!COMPAT_USE_64BIT_TIME) {
242 		if (level == SOL_SOCKET && type == SO_TIMESTAMP_OLD) {
243 			struct __kernel_old_timeval *tv = (struct __kernel_old_timeval *)data;
244 			ctv.tv_sec = tv->tv_sec;
245 			ctv.tv_usec = tv->tv_usec;
246 			data = &ctv;
247 			len = sizeof(ctv);
248 		}
249 		if (level == SOL_SOCKET &&
250 		    (type == SO_TIMESTAMPNS_OLD || type == SO_TIMESTAMPING_OLD)) {
251 			int count = type == SO_TIMESTAMPNS_OLD ? 1 : 3;
252 			int i;
253 			struct __kernel_old_timespec *ts = data;
254 			for (i = 0; i < count; i++) {
255 				cts[i].tv_sec = ts[i].tv_sec;
256 				cts[i].tv_nsec = ts[i].tv_nsec;
257 			}
258 			data = &cts;
259 			len = sizeof(cts[0]) * count;
260 		}
261 	}
262 
263 	cmlen = CMSG_COMPAT_LEN(len);
264 	if (kmsg->msg_controllen < cmlen) {
265 		kmsg->msg_flags |= MSG_CTRUNC;
266 		cmlen = kmsg->msg_controllen;
267 	}
268 	cmhdr.cmsg_level = level;
269 	cmhdr.cmsg_type = type;
270 	cmhdr.cmsg_len = cmlen;
271 
272 	if (copy_to_user(cm, &cmhdr, sizeof cmhdr))
273 		return -EFAULT;
274 	if (copy_to_user(CMSG_COMPAT_DATA(cm), data, cmlen - sizeof(struct compat_cmsghdr)))
275 		return -EFAULT;
276 	cmlen = CMSG_COMPAT_SPACE(len);
277 	if (kmsg->msg_controllen < cmlen)
278 		cmlen = kmsg->msg_controllen;
279 	kmsg->msg_control += cmlen;
280 	kmsg->msg_controllen -= cmlen;
281 	return 0;
282 }
283 
284 static int scm_max_fds_compat(struct msghdr *msg)
285 {
286 	if (msg->msg_controllen <= sizeof(struct compat_cmsghdr))
287 		return 0;
288 	return (msg->msg_controllen - sizeof(struct compat_cmsghdr)) / sizeof(int);
289 }
290 
291 void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm)
292 {
293 	struct compat_cmsghdr __user *cm =
294 		(struct compat_cmsghdr __user *)msg->msg_control;
295 	unsigned int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
296 	int fdmax = min_t(int, scm_max_fds_compat(msg), scm->fp->count);
297 	int __user *cmsg_data = CMSG_COMPAT_DATA(cm);
298 	int err = 0, i;
299 
300 	for (i = 0; i < fdmax; i++) {
301 		err = receive_fd_user(scm->fp->fp[i], cmsg_data + i, o_flags);
302 		if (err < 0)
303 			break;
304 	}
305 
306 	if (i > 0) {
307 		int cmlen = CMSG_COMPAT_LEN(i * sizeof(int));
308 
309 		err = put_user(SOL_SOCKET, &cm->cmsg_level);
310 		if (!err)
311 			err = put_user(SCM_RIGHTS, &cm->cmsg_type);
312 		if (!err)
313 			err = put_user(cmlen, &cm->cmsg_len);
314 		if (!err) {
315 			cmlen = CMSG_COMPAT_SPACE(i * sizeof(int));
316 			if (msg->msg_controllen < cmlen)
317 				cmlen = msg->msg_controllen;
318 			msg->msg_control += cmlen;
319 			msg->msg_controllen -= cmlen;
320 		}
321 	}
322 
323 	if (i < scm->fp->count || (scm->fp->count && fdmax <= 0))
324 		msg->msg_flags |= MSG_CTRUNC;
325 
326 	/*
327 	 * All of the files that fit in the message have had their usage counts
328 	 * incremented, so we just free the list.
329 	 */
330 	__scm_destroy(scm);
331 }
332 
333 /* Argument list sizes for compat_sys_socketcall */
334 #define AL(x) ((x) * sizeof(u32))
335 static unsigned char nas[21] = {
336 	AL(0), AL(3), AL(3), AL(3), AL(2), AL(3),
337 	AL(3), AL(3), AL(4), AL(4), AL(4), AL(6),
338 	AL(6), AL(2), AL(5), AL(5), AL(3), AL(3),
339 	AL(4), AL(5), AL(4)
340 };
341 #undef AL
342 
343 static inline long __compat_sys_sendmsg(int fd,
344 					struct compat_msghdr __user *msg,
345 					unsigned int flags)
346 {
347 	return __sys_sendmsg(fd, (struct user_msghdr __user *)msg,
348 			     flags | MSG_CMSG_COMPAT, false);
349 }
350 
351 COMPAT_SYSCALL_DEFINE3(sendmsg, int, fd, struct compat_msghdr __user *, msg,
352 		       unsigned int, flags)
353 {
354 	return __compat_sys_sendmsg(fd, msg, flags);
355 }
356 
357 static inline long __compat_sys_sendmmsg(int fd,
358 					 struct compat_mmsghdr __user *mmsg,
359 					 unsigned int vlen, unsigned int flags)
360 {
361 	return __sys_sendmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
362 			      flags | MSG_CMSG_COMPAT, false);
363 }
364 
365 COMPAT_SYSCALL_DEFINE4(sendmmsg, int, fd, struct compat_mmsghdr __user *, mmsg,
366 		       unsigned int, vlen, unsigned int, flags)
367 {
368 	return __compat_sys_sendmmsg(fd, mmsg, vlen, flags);
369 }
370 
371 static inline long __compat_sys_recvmsg(int fd,
372 					struct compat_msghdr __user *msg,
373 					unsigned int flags)
374 {
375 	return __sys_recvmsg(fd, (struct user_msghdr __user *)msg,
376 			     flags | MSG_CMSG_COMPAT, false);
377 }
378 
379 COMPAT_SYSCALL_DEFINE3(recvmsg, int, fd, struct compat_msghdr __user *, msg,
380 		       unsigned int, flags)
381 {
382 	return __compat_sys_recvmsg(fd, msg, flags);
383 }
384 
385 static inline long __compat_sys_recvfrom(int fd, void __user *buf,
386 					 compat_size_t len, unsigned int flags,
387 					 struct sockaddr __user *addr,
388 					 int __user *addrlen)
389 {
390 	return __sys_recvfrom(fd, buf, len, flags | MSG_CMSG_COMPAT, addr,
391 			      addrlen);
392 }
393 
394 COMPAT_SYSCALL_DEFINE4(recv, int, fd, void __user *, buf, compat_size_t, len, unsigned int, flags)
395 {
396 	return __compat_sys_recvfrom(fd, buf, len, flags, NULL, NULL);
397 }
398 
399 COMPAT_SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, buf, compat_size_t, len,
400 		       unsigned int, flags, struct sockaddr __user *, addr,
401 		       int __user *, addrlen)
402 {
403 	return __compat_sys_recvfrom(fd, buf, len, flags, addr, addrlen);
404 }
405 
406 COMPAT_SYSCALL_DEFINE5(recvmmsg_time64, int, fd, struct compat_mmsghdr __user *, mmsg,
407 		       unsigned int, vlen, unsigned int, flags,
408 		       struct __kernel_timespec __user *, timeout)
409 {
410 	return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
411 			      flags | MSG_CMSG_COMPAT, timeout, NULL);
412 }
413 
414 #ifdef CONFIG_COMPAT_32BIT_TIME
415 COMPAT_SYSCALL_DEFINE5(recvmmsg_time32, int, fd, struct compat_mmsghdr __user *, mmsg,
416 		       unsigned int, vlen, unsigned int, flags,
417 		       struct old_timespec32 __user *, timeout)
418 {
419 	return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
420 			      flags | MSG_CMSG_COMPAT, NULL, timeout);
421 }
422 #endif
423 
424 COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args)
425 {
426 	u32 a[AUDITSC_ARGS];
427 	unsigned int len;
428 	u32 a0, a1;
429 	int ret;
430 
431 	if (call < SYS_SOCKET || call > SYS_SENDMMSG)
432 		return -EINVAL;
433 	len = nas[call];
434 	if (len > sizeof(a))
435 		return -EINVAL;
436 
437 	if (copy_from_user(a, args, len))
438 		return -EFAULT;
439 
440 	ret = audit_socketcall_compat(len / sizeof(a[0]), a);
441 	if (ret)
442 		return ret;
443 
444 	a0 = a[0];
445 	a1 = a[1];
446 
447 	switch (call) {
448 	case SYS_SOCKET:
449 		ret = __sys_socket(a0, a1, a[2]);
450 		break;
451 	case SYS_BIND:
452 		ret = __sys_bind(a0, compat_ptr(a1), a[2]);
453 		break;
454 	case SYS_CONNECT:
455 		ret = __sys_connect(a0, compat_ptr(a1), a[2]);
456 		break;
457 	case SYS_LISTEN:
458 		ret = __sys_listen(a0, a1);
459 		break;
460 	case SYS_ACCEPT:
461 		ret = __sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), 0);
462 		break;
463 	case SYS_GETSOCKNAME:
464 		ret = __sys_getsockname(a0, compat_ptr(a1), compat_ptr(a[2]));
465 		break;
466 	case SYS_GETPEERNAME:
467 		ret = __sys_getpeername(a0, compat_ptr(a1), compat_ptr(a[2]));
468 		break;
469 	case SYS_SOCKETPAIR:
470 		ret = __sys_socketpair(a0, a1, a[2], compat_ptr(a[3]));
471 		break;
472 	case SYS_SEND:
473 		ret = __sys_sendto(a0, compat_ptr(a1), a[2], a[3], NULL, 0);
474 		break;
475 	case SYS_SENDTO:
476 		ret = __sys_sendto(a0, compat_ptr(a1), a[2], a[3],
477 				   compat_ptr(a[4]), a[5]);
478 		break;
479 	case SYS_RECV:
480 		ret = __compat_sys_recvfrom(a0, compat_ptr(a1), a[2], a[3],
481 					    NULL, NULL);
482 		break;
483 	case SYS_RECVFROM:
484 		ret = __compat_sys_recvfrom(a0, compat_ptr(a1), a[2], a[3],
485 					    compat_ptr(a[4]),
486 					    compat_ptr(a[5]));
487 		break;
488 	case SYS_SHUTDOWN:
489 		ret = __sys_shutdown(a0, a1);
490 		break;
491 	case SYS_SETSOCKOPT:
492 		ret = __sys_setsockopt(a0, a1, a[2], compat_ptr(a[3]), a[4]);
493 		break;
494 	case SYS_GETSOCKOPT:
495 		ret = __sys_getsockopt(a0, a1, a[2], compat_ptr(a[3]),
496 				       compat_ptr(a[4]));
497 		break;
498 	case SYS_SENDMSG:
499 		ret = __compat_sys_sendmsg(a0, compat_ptr(a1), a[2]);
500 		break;
501 	case SYS_SENDMMSG:
502 		ret = __compat_sys_sendmmsg(a0, compat_ptr(a1), a[2], a[3]);
503 		break;
504 	case SYS_RECVMSG:
505 		ret = __compat_sys_recvmsg(a0, compat_ptr(a1), a[2]);
506 		break;
507 	case SYS_RECVMMSG:
508 		ret = __sys_recvmmsg(a0, compat_ptr(a1), a[2],
509 				     a[3] | MSG_CMSG_COMPAT, NULL,
510 				     compat_ptr(a[4]));
511 		break;
512 	case SYS_ACCEPT4:
513 		ret = __sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), a[3]);
514 		break;
515 	default:
516 		ret = -EINVAL;
517 		break;
518 	}
519 	return ret;
520 }
521