xref: /linux/net/xfrm/xfrm_compat.c (revision 18f65355e112dfc87d5e2e8a299119afd2e65e7e)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * XFRM compat layer
4  * Author: Dmitry Safonov <dima@arista.com>
5  * Based on code and translator idea by: Florian Westphal <fw@strlen.de>
6  */
7 #include <linux/compat.h>
8 #include <linux/nospec.h>
9 #include <linux/xfrm.h>
10 #include <net/xfrm.h>
11 
12 struct compat_xfrm_lifetime_cfg {
13 	compat_u64 soft_byte_limit, hard_byte_limit;
14 	compat_u64 soft_packet_limit, hard_packet_limit;
15 	compat_u64 soft_add_expires_seconds, hard_add_expires_seconds;
16 	compat_u64 soft_use_expires_seconds, hard_use_expires_seconds;
17 }; /* same size on 32bit, but only 4 byte alignment required */
18 
19 struct compat_xfrm_lifetime_cur {
20 	compat_u64 bytes, packets, add_time, use_time;
21 }; /* same size on 32bit, but only 4 byte alignment required */
22 
23 struct compat_xfrm_userpolicy_info {
24 	struct xfrm_selector sel;
25 	struct compat_xfrm_lifetime_cfg lft;
26 	struct compat_xfrm_lifetime_cur curlft;
27 	__u32 priority, index;
28 	u8 dir, action, flags, share;
29 	/* 4 bytes additional padding on 64bit */
30 };
31 
32 struct compat_xfrm_usersa_info {
33 	struct xfrm_selector sel;
34 	struct xfrm_id id;
35 	xfrm_address_t saddr;
36 	struct compat_xfrm_lifetime_cfg lft;
37 	struct compat_xfrm_lifetime_cur curlft;
38 	struct xfrm_stats stats;
39 	__u32 seq, reqid;
40 	u16 family;
41 	u8 mode, replay_window, flags;
42 	/* 4 bytes additional padding on 64bit */
43 };
44 
45 struct compat_xfrm_user_acquire {
46 	struct xfrm_id id;
47 	xfrm_address_t saddr;
48 	struct xfrm_selector sel;
49 	struct compat_xfrm_userpolicy_info policy;
50 	/* 4 bytes additional padding on 64bit */
51 	__u32 aalgos, ealgos, calgos, seq;
52 };
53 
54 struct compat_xfrm_userspi_info {
55 	struct compat_xfrm_usersa_info info;
56 	/* 4 bytes additional padding on 64bit */
57 	__u32 min, max;
58 };
59 
60 struct compat_xfrm_user_expire {
61 	struct compat_xfrm_usersa_info state;
62 	/* 8 bytes additional padding on 64bit */
63 	u8 hard;
64 };
65 
66 struct compat_xfrm_user_polexpire {
67 	struct compat_xfrm_userpolicy_info pol;
68 	/* 8 bytes additional padding on 64bit */
69 	u8 hard;
70 };
71 
72 #define XMSGSIZE(type) sizeof(struct type)
73 
74 static const int compat_msg_min[XFRM_NR_MSGTYPES] = {
75 	[XFRM_MSG_NEWSA       - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_usersa_info),
76 	[XFRM_MSG_DELSA       - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_id),
77 	[XFRM_MSG_GETSA       - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_id),
78 	[XFRM_MSG_NEWPOLICY   - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_userpolicy_info),
79 	[XFRM_MSG_DELPOLICY   - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_id),
80 	[XFRM_MSG_GETPOLICY   - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_id),
81 	[XFRM_MSG_ALLOCSPI    - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_userspi_info),
82 	[XFRM_MSG_ACQUIRE     - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_user_acquire),
83 	[XFRM_MSG_EXPIRE      - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_user_expire),
84 	[XFRM_MSG_UPDPOLICY   - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_userpolicy_info),
85 	[XFRM_MSG_UPDSA       - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_usersa_info),
86 	[XFRM_MSG_POLEXPIRE   - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_user_polexpire),
87 	[XFRM_MSG_FLUSHSA     - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_flush),
88 	[XFRM_MSG_FLUSHPOLICY - XFRM_MSG_BASE] = 0,
89 	[XFRM_MSG_NEWAE       - XFRM_MSG_BASE] = XMSGSIZE(xfrm_aevent_id),
90 	[XFRM_MSG_GETAE       - XFRM_MSG_BASE] = XMSGSIZE(xfrm_aevent_id),
91 	[XFRM_MSG_REPORT      - XFRM_MSG_BASE] = XMSGSIZE(xfrm_user_report),
92 	[XFRM_MSG_MIGRATE     - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_id),
93 	[XFRM_MSG_NEWSADINFO  - XFRM_MSG_BASE] = sizeof(u32),
94 	[XFRM_MSG_GETSADINFO  - XFRM_MSG_BASE] = sizeof(u32),
95 	[XFRM_MSG_NEWSPDINFO  - XFRM_MSG_BASE] = sizeof(u32),
96 	[XFRM_MSG_GETSPDINFO  - XFRM_MSG_BASE] = sizeof(u32),
97 	[XFRM_MSG_MAPPING        - XFRM_MSG_BASE] = XMSGSIZE(xfrm_user_mapping),
98 	[XFRM_MSG_MIGRATE_STATE  - XFRM_MSG_BASE] = XMSGSIZE(xfrm_user_migrate_state),
99 };
100 
101 static const struct nla_policy compat_policy[XFRMA_MAX+1] = {
102 	[XFRMA_UNSPEC]          = { .strict_start_type = XFRMA_SA_DIR },
103 	[XFRMA_SA]		= { .len = XMSGSIZE(compat_xfrm_usersa_info)},
104 	[XFRMA_POLICY]		= { .len = XMSGSIZE(compat_xfrm_userpolicy_info)},
105 	[XFRMA_LASTUSED]	= { .type = NLA_U64},
106 	[XFRMA_ALG_AUTH_TRUNC]	= { .len = sizeof(struct xfrm_algo_auth)},
107 	[XFRMA_ALG_AEAD]	= { .len = sizeof(struct xfrm_algo_aead) },
108 	[XFRMA_ALG_AUTH]	= { .len = sizeof(struct xfrm_algo) },
109 	[XFRMA_ALG_CRYPT]	= { .len = sizeof(struct xfrm_algo) },
110 	[XFRMA_ALG_COMP]	= { .len = sizeof(struct xfrm_algo) },
111 	[XFRMA_ENCAP]		= { .len = sizeof(struct xfrm_encap_tmpl) },
112 	[XFRMA_TMPL]		= { .len = sizeof(struct xfrm_user_tmpl) },
113 	[XFRMA_SEC_CTX]		= { .len = sizeof(struct xfrm_user_sec_ctx) },
114 	[XFRMA_LTIME_VAL]	= { .len = sizeof(struct xfrm_lifetime_cur) },
115 	[XFRMA_REPLAY_VAL]	= { .len = sizeof(struct xfrm_replay_state) },
116 	[XFRMA_REPLAY_THRESH]	= { .type = NLA_U32 },
117 	[XFRMA_ETIMER_THRESH]	= { .type = NLA_U32 },
118 	[XFRMA_SRCADDR]		= { .len = sizeof(xfrm_address_t) },
119 	[XFRMA_COADDR]		= { .len = sizeof(xfrm_address_t) },
120 	[XFRMA_POLICY_TYPE]	= { .len = sizeof(struct xfrm_userpolicy_type)},
121 	[XFRMA_MIGRATE]		= { .len = sizeof(struct xfrm_user_migrate) },
122 	[XFRMA_KMADDRESS]	= { .len = sizeof(struct xfrm_user_kmaddress) },
123 	[XFRMA_MARK]		= { .len = sizeof(struct xfrm_mark) },
124 	[XFRMA_TFCPAD]		= { .type = NLA_U32 },
125 	[XFRMA_REPLAY_ESN_VAL]	= { .len = sizeof(struct xfrm_replay_state_esn) },
126 	[XFRMA_SA_EXTRA_FLAGS]	= { .type = NLA_U32 },
127 	[XFRMA_PROTO]		= { .type = NLA_U8 },
128 	[XFRMA_ADDRESS_FILTER]	= { .len = sizeof(struct xfrm_address_filter) },
129 	[XFRMA_OFFLOAD_DEV]	= { .len = sizeof(struct xfrm_user_offload) },
130 	[XFRMA_SET_MARK]	= { .type = NLA_U32 },
131 	[XFRMA_SET_MARK_MASK]	= { .type = NLA_U32 },
132 	[XFRMA_IF_ID]		= { .type = NLA_U32 },
133 	[XFRMA_MTIMER_THRESH]	= { .type = NLA_U32 },
134 	[XFRMA_SA_DIR]          = NLA_POLICY_RANGE(NLA_U8, XFRM_SA_DIR_IN, XFRM_SA_DIR_OUT),
135 	[XFRMA_NAT_KEEPALIVE_INTERVAL]	= { .type = NLA_U32 },
136 	[XFRMA_SA_PCPU]		= { .type = NLA_U32 },
137 };
138 
139 static struct nlmsghdr *xfrm_nlmsg_put_compat(struct sk_buff *skb,
140 			const struct nlmsghdr *nlh_src, u16 type)
141 {
142 	int payload = compat_msg_min[type];
143 	int src_len = xfrm_msg_min[type];
144 	struct nlmsghdr *nlh_dst;
145 
146 	/* Compat messages are shorter or equal to native (+padding) */
147 	if (WARN_ON_ONCE(src_len < payload))
148 		return ERR_PTR(-EMSGSIZE);
149 
150 	nlh_dst = nlmsg_put(skb, nlh_src->nlmsg_pid, nlh_src->nlmsg_seq,
151 			    nlh_src->nlmsg_type, payload, nlh_src->nlmsg_flags);
152 	if (!nlh_dst)
153 		return ERR_PTR(-EMSGSIZE);
154 
155 	memset(nlmsg_data(nlh_dst), 0, payload);
156 
157 	switch (nlh_src->nlmsg_type) {
158 	/* Compat message has the same layout as native */
159 	case XFRM_MSG_DELSA:
160 	case XFRM_MSG_DELPOLICY:
161 	case XFRM_MSG_FLUSHSA:
162 	case XFRM_MSG_FLUSHPOLICY:
163 	case XFRM_MSG_NEWAE:
164 	case XFRM_MSG_REPORT:
165 	case XFRM_MSG_MIGRATE:
166 	case XFRM_MSG_MIGRATE_STATE:
167 	case XFRM_MSG_NEWSADINFO:
168 	case XFRM_MSG_NEWSPDINFO:
169 	case XFRM_MSG_MAPPING:
170 		WARN_ON_ONCE(src_len != payload);
171 		memcpy(nlmsg_data(nlh_dst), nlmsg_data(nlh_src), src_len);
172 		break;
173 	/* 4 byte alignment for trailing u64 on native, but not on compat */
174 	case XFRM_MSG_NEWSA:
175 	case XFRM_MSG_NEWPOLICY:
176 	case XFRM_MSG_UPDSA:
177 	case XFRM_MSG_UPDPOLICY:
178 		WARN_ON_ONCE(src_len != payload + 4);
179 		memcpy(nlmsg_data(nlh_dst), nlmsg_data(nlh_src), payload);
180 		break;
181 	case XFRM_MSG_EXPIRE: {
182 		const struct xfrm_user_expire *src_ue  = nlmsg_data(nlh_src);
183 		struct compat_xfrm_user_expire *dst_ue = nlmsg_data(nlh_dst);
184 
185 		/* compat_xfrm_user_expire has 4-byte smaller state */
186 		memcpy(dst_ue, src_ue, sizeof(dst_ue->state));
187 		dst_ue->hard = src_ue->hard;
188 		break;
189 	}
190 	case XFRM_MSG_ACQUIRE: {
191 		const struct xfrm_user_acquire *src_ua  = nlmsg_data(nlh_src);
192 		struct compat_xfrm_user_acquire *dst_ua = nlmsg_data(nlh_dst);
193 
194 		memcpy(dst_ua, src_ua, offsetof(struct compat_xfrm_user_acquire, aalgos));
195 		dst_ua->aalgos = src_ua->aalgos;
196 		dst_ua->ealgos = src_ua->ealgos;
197 		dst_ua->calgos = src_ua->calgos;
198 		dst_ua->seq    = src_ua->seq;
199 		break;
200 	}
201 	case XFRM_MSG_POLEXPIRE: {
202 		const struct xfrm_user_polexpire *src_upe  = nlmsg_data(nlh_src);
203 		struct compat_xfrm_user_polexpire *dst_upe = nlmsg_data(nlh_dst);
204 
205 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
206 		memcpy(dst_upe, src_upe, sizeof(dst_upe->pol));
207 		dst_upe->hard = src_upe->hard;
208 		break;
209 	}
210 	case XFRM_MSG_ALLOCSPI: {
211 		const struct xfrm_userspi_info *src_usi = nlmsg_data(nlh_src);
212 		struct compat_xfrm_userspi_info *dst_usi = nlmsg_data(nlh_dst);
213 
214 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
215 		memcpy(dst_usi, src_usi, sizeof(src_usi->info));
216 		dst_usi->min = src_usi->min;
217 		dst_usi->max = src_usi->max;
218 		break;
219 	}
220 	/* Not being sent by kernel */
221 	case XFRM_MSG_GETSA:
222 	case XFRM_MSG_GETPOLICY:
223 	case XFRM_MSG_GETAE:
224 	case XFRM_MSG_GETSADINFO:
225 	case XFRM_MSG_GETSPDINFO:
226 	default:
227 		pr_warn_once("unsupported nlmsg_type %d\n", nlh_src->nlmsg_type);
228 		return ERR_PTR(-EOPNOTSUPP);
229 	}
230 
231 	return nlh_dst;
232 }
233 
234 static int xfrm_nla_cpy(struct sk_buff *dst, const struct nlattr *src, int len)
235 {
236 	return nla_put(dst, src->nla_type, len, nla_data(src));
237 }
238 
239 static int xfrm_xlate64_attr(struct sk_buff *dst, const struct nlattr *src)
240 {
241 	switch (src->nla_type) {
242 	case XFRMA_PAD:
243 		/* Ignore */
244 		return 0;
245 	case XFRMA_UNSPEC:
246 	case XFRMA_ALG_AUTH:
247 	case XFRMA_ALG_CRYPT:
248 	case XFRMA_ALG_COMP:
249 	case XFRMA_ENCAP:
250 	case XFRMA_TMPL:
251 		return xfrm_nla_cpy(dst, src, nla_len(src));
252 	case XFRMA_SA:
253 		return xfrm_nla_cpy(dst, src, XMSGSIZE(compat_xfrm_usersa_info));
254 	case XFRMA_POLICY:
255 		return xfrm_nla_cpy(dst, src, XMSGSIZE(compat_xfrm_userpolicy_info));
256 	case XFRMA_SEC_CTX:
257 		return xfrm_nla_cpy(dst, src, nla_len(src));
258 	case XFRMA_LTIME_VAL:
259 		return nla_put_64bit(dst, src->nla_type, nla_len(src),
260 			nla_data(src), XFRMA_PAD);
261 	case XFRMA_REPLAY_VAL:
262 	case XFRMA_REPLAY_THRESH:
263 	case XFRMA_ETIMER_THRESH:
264 	case XFRMA_SRCADDR:
265 	case XFRMA_COADDR:
266 		return xfrm_nla_cpy(dst, src, nla_len(src));
267 	case XFRMA_LASTUSED:
268 		return nla_put_64bit(dst, src->nla_type, nla_len(src),
269 			nla_data(src), XFRMA_PAD);
270 	case XFRMA_POLICY_TYPE:
271 	case XFRMA_MIGRATE:
272 	case XFRMA_ALG_AEAD:
273 	case XFRMA_KMADDRESS:
274 	case XFRMA_ALG_AUTH_TRUNC:
275 	case XFRMA_MARK:
276 	case XFRMA_TFCPAD:
277 	case XFRMA_REPLAY_ESN_VAL:
278 	case XFRMA_SA_EXTRA_FLAGS:
279 	case XFRMA_PROTO:
280 	case XFRMA_ADDRESS_FILTER:
281 	case XFRMA_OFFLOAD_DEV:
282 	case XFRMA_SET_MARK:
283 	case XFRMA_SET_MARK_MASK:
284 	case XFRMA_IF_ID:
285 	case XFRMA_MTIMER_THRESH:
286 	case XFRMA_SA_DIR:
287 	case XFRMA_NAT_KEEPALIVE_INTERVAL:
288 	case XFRMA_SA_PCPU:
289 	case XFRMA_IPTFS_DROP_TIME:
290 	case XFRMA_IPTFS_REORDER_WINDOW:
291 	case XFRMA_IPTFS_DONT_FRAG:
292 	case XFRMA_IPTFS_INIT_DELAY:
293 	case XFRMA_IPTFS_MAX_QSIZE:
294 	case XFRMA_IPTFS_PKT_SIZE:
295 		return xfrm_nla_cpy(dst, src, nla_len(src));
296 	default:
297 		BUILD_BUG_ON(XFRMA_MAX != XFRMA_IPTFS_PKT_SIZE);
298 		pr_warn_once("unsupported nla_type %d\n", src->nla_type);
299 		return -EOPNOTSUPP;
300 	}
301 }
302 
303 /* Take kernel-built (64bit layout) and create 32bit layout for userspace */
304 static int xfrm_xlate64(struct sk_buff *dst, const struct nlmsghdr *nlh_src)
305 {
306 	u16 type = nlh_src->nlmsg_type - XFRM_MSG_BASE;
307 	const struct nlattr *nla, *attrs;
308 	struct nlmsghdr *nlh_dst;
309 	int len, remaining;
310 
311 	nlh_dst = xfrm_nlmsg_put_compat(dst, nlh_src, type);
312 	if (IS_ERR(nlh_dst))
313 		return PTR_ERR(nlh_dst);
314 
315 	attrs = nlmsg_attrdata(nlh_src, xfrm_msg_min[type]);
316 	len = nlmsg_attrlen(nlh_src, xfrm_msg_min[type]);
317 
318 	nla_for_each_attr(nla, attrs, len, remaining) {
319 		int err;
320 
321 		switch (nlh_src->nlmsg_type) {
322 		case XFRM_MSG_NEWSPDINFO:
323 			err = xfrm_nla_cpy(dst, nla, nla_len(nla));
324 			break;
325 		default:
326 			err = xfrm_xlate64_attr(dst, nla);
327 			break;
328 		}
329 		if (err)
330 			return err;
331 	}
332 
333 	nlmsg_end(dst, nlh_dst);
334 
335 	return 0;
336 }
337 
338 static int xfrm_alloc_compat(struct sk_buff *skb, const struct nlmsghdr *nlh_src)
339 {
340 	u16 type = nlh_src->nlmsg_type - XFRM_MSG_BASE;
341 	struct sk_buff *new = NULL;
342 	int err;
343 
344 	if (type >= ARRAY_SIZE(xfrm_msg_min)) {
345 		pr_warn_once("unsupported nlmsg_type %d\n", nlh_src->nlmsg_type);
346 		return -EOPNOTSUPP;
347 	}
348 
349 	if (skb_shinfo(skb)->frag_list == NULL) {
350 		new = alloc_skb(skb->len + skb_tailroom(skb), GFP_ATOMIC);
351 		if (!new)
352 			return -ENOMEM;
353 		skb_shinfo(skb)->frag_list = new;
354 	}
355 
356 	err = xfrm_xlate64(skb_shinfo(skb)->frag_list, nlh_src);
357 	if (err) {
358 		if (new) {
359 			kfree_skb(new);
360 			skb_shinfo(skb)->frag_list = NULL;
361 		}
362 		return err;
363 	}
364 
365 	return 0;
366 }
367 
368 /* Calculates len of translated 64-bit message. */
369 static size_t xfrm_user_rcv_calculate_len64(const struct nlmsghdr *src,
370 					    struct nlattr *attrs[XFRMA_MAX + 1],
371 					    int maxtype)
372 {
373 	size_t len = nlmsg_len(src);
374 
375 	switch (src->nlmsg_type) {
376 	case XFRM_MSG_NEWSA:
377 	case XFRM_MSG_NEWPOLICY:
378 	case XFRM_MSG_ALLOCSPI:
379 	case XFRM_MSG_ACQUIRE:
380 	case XFRM_MSG_UPDPOLICY:
381 	case XFRM_MSG_UPDSA:
382 		len += 4;
383 		break;
384 	case XFRM_MSG_EXPIRE:
385 	case XFRM_MSG_POLEXPIRE:
386 		len += 8;
387 		break;
388 	case XFRM_MSG_NEWSPDINFO:
389 		/* attirbutes are xfrm_spdattr_type_t, not xfrm_attr_type_t */
390 		return len;
391 	default:
392 		break;
393 	}
394 
395 	/* Unexpected for anything, but XFRM_MSG_NEWSPDINFO, please
396 	 * correct both 64=>32-bit and 32=>64-bit translators to copy
397 	 * new attributes.
398 	 */
399 	if (WARN_ON_ONCE(maxtype))
400 		return len;
401 
402 	if (attrs[XFRMA_SA])
403 		len += 4;
404 	if (attrs[XFRMA_POLICY])
405 		len += 4;
406 
407 	/* XXX: some attrs may need to be realigned
408 	 * if !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
409 	 */
410 
411 	return len;
412 }
413 
414 static int xfrm_attr_cpy32(void *dst, size_t *pos, const struct nlattr *src,
415 			   size_t size, int copy_len, int payload)
416 {
417 	struct nlmsghdr *nlmsg = dst;
418 	struct nlattr *nla;
419 
420 	/* xfrm_user_rcv_msg_compat() relies on fact that 32-bit messages
421 	 * have the same len or shorted than 64-bit ones.
422 	 * 32-bit translation that is bigger than 64-bit original is unexpected.
423 	 */
424 	if (WARN_ON_ONCE(copy_len > payload))
425 		copy_len = payload;
426 
427 	if (size - *pos < nla_attr_size(payload))
428 		return -ENOBUFS;
429 
430 	nla = dst + *pos;
431 
432 	memcpy(nla, src, nla_attr_size(copy_len));
433 	nla->nla_len = nla_attr_size(payload);
434 	*pos += nla_attr_size(copy_len);
435 	nlmsg->nlmsg_len += nla->nla_len;
436 
437 	memset(dst + *pos, 0, payload - copy_len);
438 	*pos += payload - copy_len;
439 
440 	return 0;
441 }
442 
443 static int xfrm_xlate32_attr(void *dst, const struct nlattr *nla,
444 			     size_t *pos, size_t size,
445 			     struct netlink_ext_ack *extack)
446 {
447 	int type = nla_type(nla);
448 	u16 pol_len32, pol_len64;
449 	int err;
450 
451 	if (type > XFRMA_MAX) {
452 		BUILD_BUG_ON(XFRMA_MAX != XFRMA_IPTFS_PKT_SIZE);
453 		NL_SET_ERR_MSG(extack, "Bad attribute");
454 		return -EOPNOTSUPP;
455 	}
456 	type = array_index_nospec(type, XFRMA_MAX + 1);
457 	if (nla_len(nla) < compat_policy[type].len) {
458 		NL_SET_ERR_MSG(extack, "Attribute bad length");
459 		return -EOPNOTSUPP;
460 	}
461 
462 	pol_len32 = compat_policy[type].len;
463 	pol_len64 = xfrma_policy[type].len;
464 
465 	/* XFRMA_SA and XFRMA_POLICY - need to know how-to translate */
466 	if (pol_len32 != pol_len64) {
467 		if (nla_len(nla) != compat_policy[type].len) {
468 			NL_SET_ERR_MSG(extack, "Attribute bad length");
469 			return -EOPNOTSUPP;
470 		}
471 		err = xfrm_attr_cpy32(dst, pos, nla, size, pol_len32, pol_len64);
472 		if (err)
473 			return err;
474 	}
475 
476 	return xfrm_attr_cpy32(dst, pos, nla, size, nla_len(nla), nla_len(nla));
477 }
478 
479 static int xfrm_xlate32(struct nlmsghdr *dst, const struct nlmsghdr *src,
480 			struct nlattr *attrs[XFRMA_MAX+1],
481 			size_t size, u8 type, int maxtype,
482 			struct netlink_ext_ack *extack)
483 {
484 	size_t pos;
485 	int i;
486 
487 	memcpy(dst, src, NLMSG_HDRLEN);
488 	dst->nlmsg_len = NLMSG_HDRLEN + xfrm_msg_min[type];
489 	memset(nlmsg_data(dst), 0, xfrm_msg_min[type]);
490 
491 	switch (src->nlmsg_type) {
492 	/* Compat message has the same layout as native */
493 	case XFRM_MSG_DELSA:
494 	case XFRM_MSG_GETSA:
495 	case XFRM_MSG_DELPOLICY:
496 	case XFRM_MSG_GETPOLICY:
497 	case XFRM_MSG_FLUSHSA:
498 	case XFRM_MSG_FLUSHPOLICY:
499 	case XFRM_MSG_NEWAE:
500 	case XFRM_MSG_GETAE:
501 	case XFRM_MSG_REPORT:
502 	case XFRM_MSG_MIGRATE:
503 	case XFRM_MSG_MIGRATE_STATE:
504 	case XFRM_MSG_NEWSADINFO:
505 	case XFRM_MSG_GETSADINFO:
506 	case XFRM_MSG_NEWSPDINFO:
507 	case XFRM_MSG_GETSPDINFO:
508 	case XFRM_MSG_MAPPING:
509 		memcpy(nlmsg_data(dst), nlmsg_data(src), compat_msg_min[type]);
510 		break;
511 	/* 4 byte alignment for trailing u64 on native, but not on compat */
512 	case XFRM_MSG_NEWSA:
513 	case XFRM_MSG_NEWPOLICY:
514 	case XFRM_MSG_UPDSA:
515 	case XFRM_MSG_UPDPOLICY:
516 		memcpy(nlmsg_data(dst), nlmsg_data(src), compat_msg_min[type]);
517 		break;
518 	case XFRM_MSG_EXPIRE: {
519 		const struct compat_xfrm_user_expire *src_ue = nlmsg_data(src);
520 		struct xfrm_user_expire *dst_ue = nlmsg_data(dst);
521 
522 		/* compat_xfrm_user_expire has 4-byte smaller state */
523 		memcpy(dst_ue, src_ue, sizeof(src_ue->state));
524 		dst_ue->hard = src_ue->hard;
525 		break;
526 	}
527 	case XFRM_MSG_ACQUIRE: {
528 		const struct compat_xfrm_user_acquire *src_ua = nlmsg_data(src);
529 		struct xfrm_user_acquire *dst_ua = nlmsg_data(dst);
530 
531 		memcpy(dst_ua, src_ua, offsetof(struct compat_xfrm_user_acquire, aalgos));
532 		dst_ua->aalgos = src_ua->aalgos;
533 		dst_ua->ealgos = src_ua->ealgos;
534 		dst_ua->calgos = src_ua->calgos;
535 		dst_ua->seq    = src_ua->seq;
536 		break;
537 	}
538 	case XFRM_MSG_POLEXPIRE: {
539 		const struct compat_xfrm_user_polexpire *src_upe = nlmsg_data(src);
540 		struct xfrm_user_polexpire *dst_upe = nlmsg_data(dst);
541 
542 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
543 		memcpy(dst_upe, src_upe, sizeof(src_upe->pol));
544 		dst_upe->hard = src_upe->hard;
545 		break;
546 	}
547 	case XFRM_MSG_ALLOCSPI: {
548 		const struct compat_xfrm_userspi_info *src_usi = nlmsg_data(src);
549 		struct xfrm_userspi_info *dst_usi = nlmsg_data(dst);
550 
551 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
552 		memcpy(dst_usi, src_usi, sizeof(src_usi->info));
553 		dst_usi->min = src_usi->min;
554 		dst_usi->max = src_usi->max;
555 		break;
556 	}
557 	default:
558 		NL_SET_ERR_MSG(extack, "Unsupported message type");
559 		return -EOPNOTSUPP;
560 	}
561 	pos = dst->nlmsg_len;
562 
563 	if (maxtype) {
564 		/* attirbutes are xfrm_spdattr_type_t, not xfrm_attr_type_t */
565 		WARN_ON_ONCE(src->nlmsg_type != XFRM_MSG_NEWSPDINFO);
566 
567 		for (i = 1; i <= maxtype; i++) {
568 			int err;
569 
570 			if (!attrs[i])
571 				continue;
572 
573 			/* just copy - no need for translation */
574 			err = xfrm_attr_cpy32(dst, &pos, attrs[i], size,
575 					nla_len(attrs[i]), nla_len(attrs[i]));
576 			if (err)
577 				return err;
578 		}
579 		return 0;
580 	}
581 
582 	for (i = 1; i < XFRMA_MAX + 1; i++) {
583 		int err;
584 
585 		if (i == XFRMA_PAD)
586 			continue;
587 
588 		if (!attrs[i])
589 			continue;
590 
591 		err = xfrm_xlate32_attr(dst, attrs[i], &pos, size, extack);
592 		if (err)
593 			return err;
594 	}
595 
596 	return 0;
597 }
598 
599 static struct nlmsghdr *xfrm_user_rcv_msg_compat(const struct nlmsghdr *h32,
600 			int maxtype, const struct nla_policy *policy,
601 			struct netlink_ext_ack *extack)
602 {
603 	/* netlink_rcv_skb() checks if a message has full (struct nlmsghdr) */
604 	u16 type = h32->nlmsg_type - XFRM_MSG_BASE;
605 	struct nlattr *attrs[XFRMA_MAX+1];
606 	struct nlmsghdr *h64;
607 	size_t len;
608 	int err;
609 
610 	BUILD_BUG_ON(ARRAY_SIZE(xfrm_msg_min) != ARRAY_SIZE(compat_msg_min));
611 
612 	if (type >= ARRAY_SIZE(xfrm_msg_min))
613 		return ERR_PTR(-EINVAL);
614 
615 	/* Don't call parse: the message might have only nlmsg header */
616 	if ((h32->nlmsg_type == XFRM_MSG_GETSA ||
617 	     h32->nlmsg_type == XFRM_MSG_GETPOLICY) &&
618 	    (h32->nlmsg_flags & NLM_F_DUMP))
619 		return NULL;
620 
621 	err = nlmsg_parse_deprecated(h32, compat_msg_min[type], attrs,
622 			maxtype ? : XFRMA_MAX, policy ? : compat_policy, extack);
623 	if (err < 0)
624 		return ERR_PTR(err);
625 
626 	len = xfrm_user_rcv_calculate_len64(h32, attrs, maxtype);
627 	/* The message doesn't need translation */
628 	if (len == nlmsg_len(h32))
629 		return NULL;
630 
631 	len += NLMSG_HDRLEN;
632 	h64 = kvmalloc(len, GFP_KERNEL);
633 	if (!h64)
634 		return ERR_PTR(-ENOMEM);
635 
636 	err = xfrm_xlate32(h64, h32, attrs, len, type, maxtype, extack);
637 	if (err < 0) {
638 		kvfree(h64);
639 		return ERR_PTR(err);
640 	}
641 
642 	return h64;
643 }
644 
645 static int xfrm_user_policy_compat(u8 **pdata32, int optlen)
646 {
647 	struct compat_xfrm_userpolicy_info *p = (void *)*pdata32;
648 	u8 *src_templates, *dst_templates;
649 	u8 *data64;
650 
651 	if (optlen < sizeof(*p))
652 		return -EINVAL;
653 
654 	data64 = kmalloc_track_caller(optlen + 4, GFP_USER | __GFP_NOWARN);
655 	if (!data64)
656 		return -ENOMEM;
657 
658 	memcpy(data64, *pdata32, sizeof(*p));
659 	memset(data64 + sizeof(*p), 0, 4);
660 
661 	src_templates = *pdata32 + sizeof(*p);
662 	dst_templates = data64 + sizeof(*p) + 4;
663 	memcpy(dst_templates, src_templates, optlen - sizeof(*p));
664 
665 	kfree(*pdata32);
666 	*pdata32 = data64;
667 	return 0;
668 }
669 
670 static struct xfrm_translator xfrm_translator = {
671 	.owner				= THIS_MODULE,
672 	.alloc_compat			= xfrm_alloc_compat,
673 	.rcv_msg_compat			= xfrm_user_rcv_msg_compat,
674 	.xlate_user_policy_sockptr	= xfrm_user_policy_compat,
675 };
676 
677 static int __init xfrm_compat_init(void)
678 {
679 	return xfrm_register_translator(&xfrm_translator);
680 }
681 
682 static void __exit xfrm_compat_exit(void)
683 {
684 	xfrm_unregister_translator(&xfrm_translator);
685 }
686 
687 module_init(xfrm_compat_init);
688 module_exit(xfrm_compat_exit);
689 MODULE_LICENSE("GPL");
690 MODULE_AUTHOR("Dmitry Safonov");
691 MODULE_DESCRIPTION("XFRM 32-bit compatibility layer");
692