xref: /linux/net/xfrm/xfrm_compat.c (revision 447e140e66fd226350b3ce86cffc965eaae4c856)
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 };
99 
100 static const struct nla_policy compat_policy[XFRMA_MAX+1] = {
101 	[XFRMA_UNSPEC]          = { .strict_start_type = XFRMA_SA_DIR },
102 	[XFRMA_SA]		= { .len = XMSGSIZE(compat_xfrm_usersa_info)},
103 	[XFRMA_POLICY]		= { .len = XMSGSIZE(compat_xfrm_userpolicy_info)},
104 	[XFRMA_LASTUSED]	= { .type = NLA_U64},
105 	[XFRMA_ALG_AUTH_TRUNC]	= { .len = sizeof(struct xfrm_algo_auth)},
106 	[XFRMA_ALG_AEAD]	= { .len = sizeof(struct xfrm_algo_aead) },
107 	[XFRMA_ALG_AUTH]	= { .len = sizeof(struct xfrm_algo) },
108 	[XFRMA_ALG_CRYPT]	= { .len = sizeof(struct xfrm_algo) },
109 	[XFRMA_ALG_COMP]	= { .len = sizeof(struct xfrm_algo) },
110 	[XFRMA_ENCAP]		= { .len = sizeof(struct xfrm_encap_tmpl) },
111 	[XFRMA_TMPL]		= { .len = sizeof(struct xfrm_user_tmpl) },
112 	[XFRMA_SEC_CTX]		= { .len = sizeof(struct xfrm_user_sec_ctx) },
113 	[XFRMA_LTIME_VAL]	= { .len = sizeof(struct xfrm_lifetime_cur) },
114 	[XFRMA_REPLAY_VAL]	= { .len = sizeof(struct xfrm_replay_state) },
115 	[XFRMA_REPLAY_THRESH]	= { .type = NLA_U32 },
116 	[XFRMA_ETIMER_THRESH]	= { .type = NLA_U32 },
117 	[XFRMA_SRCADDR]		= { .len = sizeof(xfrm_address_t) },
118 	[XFRMA_COADDR]		= { .len = sizeof(xfrm_address_t) },
119 	[XFRMA_POLICY_TYPE]	= { .len = sizeof(struct xfrm_userpolicy_type)},
120 	[XFRMA_MIGRATE]		= { .len = sizeof(struct xfrm_user_migrate) },
121 	[XFRMA_KMADDRESS]	= { .len = sizeof(struct xfrm_user_kmaddress) },
122 	[XFRMA_MARK]		= { .len = sizeof(struct xfrm_mark) },
123 	[XFRMA_TFCPAD]		= { .type = NLA_U32 },
124 	[XFRMA_REPLAY_ESN_VAL]	= { .len = sizeof(struct xfrm_replay_state_esn) },
125 	[XFRMA_SA_EXTRA_FLAGS]	= { .type = NLA_U32 },
126 	[XFRMA_PROTO]		= { .type = NLA_U8 },
127 	[XFRMA_ADDRESS_FILTER]	= { .len = sizeof(struct xfrm_address_filter) },
128 	[XFRMA_OFFLOAD_DEV]	= { .len = sizeof(struct xfrm_user_offload) },
129 	[XFRMA_SET_MARK]	= { .type = NLA_U32 },
130 	[XFRMA_SET_MARK_MASK]	= { .type = NLA_U32 },
131 	[XFRMA_IF_ID]		= { .type = NLA_U32 },
132 	[XFRMA_MTIMER_THRESH]	= { .type = NLA_U32 },
133 	[XFRMA_SA_DIR]          = NLA_POLICY_RANGE(NLA_U8, XFRM_SA_DIR_IN, XFRM_SA_DIR_OUT),
134 };
135 
136 static struct nlmsghdr *xfrm_nlmsg_put_compat(struct sk_buff *skb,
137 			const struct nlmsghdr *nlh_src, u16 type)
138 {
139 	int payload = compat_msg_min[type];
140 	int src_len = xfrm_msg_min[type];
141 	struct nlmsghdr *nlh_dst;
142 
143 	/* Compat messages are shorter or equal to native (+padding) */
144 	if (WARN_ON_ONCE(src_len < payload))
145 		return ERR_PTR(-EMSGSIZE);
146 
147 	nlh_dst = nlmsg_put(skb, nlh_src->nlmsg_pid, nlh_src->nlmsg_seq,
148 			    nlh_src->nlmsg_type, payload, nlh_src->nlmsg_flags);
149 	if (!nlh_dst)
150 		return ERR_PTR(-EMSGSIZE);
151 
152 	memset(nlmsg_data(nlh_dst), 0, payload);
153 
154 	switch (nlh_src->nlmsg_type) {
155 	/* Compat message has the same layout as native */
156 	case XFRM_MSG_DELSA:
157 	case XFRM_MSG_DELPOLICY:
158 	case XFRM_MSG_FLUSHSA:
159 	case XFRM_MSG_FLUSHPOLICY:
160 	case XFRM_MSG_NEWAE:
161 	case XFRM_MSG_REPORT:
162 	case XFRM_MSG_MIGRATE:
163 	case XFRM_MSG_NEWSADINFO:
164 	case XFRM_MSG_NEWSPDINFO:
165 	case XFRM_MSG_MAPPING:
166 		WARN_ON_ONCE(src_len != payload);
167 		memcpy(nlmsg_data(nlh_dst), nlmsg_data(nlh_src), src_len);
168 		break;
169 	/* 4 byte alignment for trailing u64 on native, but not on compat */
170 	case XFRM_MSG_NEWSA:
171 	case XFRM_MSG_NEWPOLICY:
172 	case XFRM_MSG_UPDSA:
173 	case XFRM_MSG_UPDPOLICY:
174 		WARN_ON_ONCE(src_len != payload + 4);
175 		memcpy(nlmsg_data(nlh_dst), nlmsg_data(nlh_src), payload);
176 		break;
177 	case XFRM_MSG_EXPIRE: {
178 		const struct xfrm_user_expire *src_ue  = nlmsg_data(nlh_src);
179 		struct compat_xfrm_user_expire *dst_ue = nlmsg_data(nlh_dst);
180 
181 		/* compat_xfrm_user_expire has 4-byte smaller state */
182 		memcpy(dst_ue, src_ue, sizeof(dst_ue->state));
183 		dst_ue->hard = src_ue->hard;
184 		break;
185 	}
186 	case XFRM_MSG_ACQUIRE: {
187 		const struct xfrm_user_acquire *src_ua  = nlmsg_data(nlh_src);
188 		struct compat_xfrm_user_acquire *dst_ua = nlmsg_data(nlh_dst);
189 
190 		memcpy(dst_ua, src_ua, offsetof(struct compat_xfrm_user_acquire, aalgos));
191 		dst_ua->aalgos = src_ua->aalgos;
192 		dst_ua->ealgos = src_ua->ealgos;
193 		dst_ua->calgos = src_ua->calgos;
194 		dst_ua->seq    = src_ua->seq;
195 		break;
196 	}
197 	case XFRM_MSG_POLEXPIRE: {
198 		const struct xfrm_user_polexpire *src_upe  = nlmsg_data(nlh_src);
199 		struct compat_xfrm_user_polexpire *dst_upe = nlmsg_data(nlh_dst);
200 
201 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
202 		memcpy(dst_upe, src_upe, sizeof(dst_upe->pol));
203 		dst_upe->hard = src_upe->hard;
204 		break;
205 	}
206 	case XFRM_MSG_ALLOCSPI: {
207 		const struct xfrm_userspi_info *src_usi = nlmsg_data(nlh_src);
208 		struct compat_xfrm_userspi_info *dst_usi = nlmsg_data(nlh_dst);
209 
210 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
211 		memcpy(dst_usi, src_usi, sizeof(src_usi->info));
212 		dst_usi->min = src_usi->min;
213 		dst_usi->max = src_usi->max;
214 		break;
215 	}
216 	/* Not being sent by kernel */
217 	case XFRM_MSG_GETSA:
218 	case XFRM_MSG_GETPOLICY:
219 	case XFRM_MSG_GETAE:
220 	case XFRM_MSG_GETSADINFO:
221 	case XFRM_MSG_GETSPDINFO:
222 	default:
223 		pr_warn_once("unsupported nlmsg_type %d\n", nlh_src->nlmsg_type);
224 		return ERR_PTR(-EOPNOTSUPP);
225 	}
226 
227 	return nlh_dst;
228 }
229 
230 static int xfrm_nla_cpy(struct sk_buff *dst, const struct nlattr *src, int len)
231 {
232 	return nla_put(dst, src->nla_type, len, nla_data(src));
233 }
234 
235 static int xfrm_xlate64_attr(struct sk_buff *dst, const struct nlattr *src)
236 {
237 	switch (src->nla_type) {
238 	case XFRMA_PAD:
239 		/* Ignore */
240 		return 0;
241 	case XFRMA_UNSPEC:
242 	case XFRMA_ALG_AUTH:
243 	case XFRMA_ALG_CRYPT:
244 	case XFRMA_ALG_COMP:
245 	case XFRMA_ENCAP:
246 	case XFRMA_TMPL:
247 		return xfrm_nla_cpy(dst, src, nla_len(src));
248 	case XFRMA_SA:
249 		return xfrm_nla_cpy(dst, src, XMSGSIZE(compat_xfrm_usersa_info));
250 	case XFRMA_POLICY:
251 		return xfrm_nla_cpy(dst, src, XMSGSIZE(compat_xfrm_userpolicy_info));
252 	case XFRMA_SEC_CTX:
253 		return xfrm_nla_cpy(dst, src, nla_len(src));
254 	case XFRMA_LTIME_VAL:
255 		return nla_put_64bit(dst, src->nla_type, nla_len(src),
256 			nla_data(src), XFRMA_PAD);
257 	case XFRMA_REPLAY_VAL:
258 	case XFRMA_REPLAY_THRESH:
259 	case XFRMA_ETIMER_THRESH:
260 	case XFRMA_SRCADDR:
261 	case XFRMA_COADDR:
262 		return xfrm_nla_cpy(dst, src, nla_len(src));
263 	case XFRMA_LASTUSED:
264 		return nla_put_64bit(dst, src->nla_type, nla_len(src),
265 			nla_data(src), XFRMA_PAD);
266 	case XFRMA_POLICY_TYPE:
267 	case XFRMA_MIGRATE:
268 	case XFRMA_ALG_AEAD:
269 	case XFRMA_KMADDRESS:
270 	case XFRMA_ALG_AUTH_TRUNC:
271 	case XFRMA_MARK:
272 	case XFRMA_TFCPAD:
273 	case XFRMA_REPLAY_ESN_VAL:
274 	case XFRMA_SA_EXTRA_FLAGS:
275 	case XFRMA_PROTO:
276 	case XFRMA_ADDRESS_FILTER:
277 	case XFRMA_OFFLOAD_DEV:
278 	case XFRMA_SET_MARK:
279 	case XFRMA_SET_MARK_MASK:
280 	case XFRMA_IF_ID:
281 	case XFRMA_MTIMER_THRESH:
282 	case XFRMA_SA_DIR:
283 		return xfrm_nla_cpy(dst, src, nla_len(src));
284 	default:
285 		BUILD_BUG_ON(XFRMA_MAX != XFRMA_SA_DIR);
286 		pr_warn_once("unsupported nla_type %d\n", src->nla_type);
287 		return -EOPNOTSUPP;
288 	}
289 }
290 
291 /* Take kernel-built (64bit layout) and create 32bit layout for userspace */
292 static int xfrm_xlate64(struct sk_buff *dst, const struct nlmsghdr *nlh_src)
293 {
294 	u16 type = nlh_src->nlmsg_type - XFRM_MSG_BASE;
295 	const struct nlattr *nla, *attrs;
296 	struct nlmsghdr *nlh_dst;
297 	int len, remaining;
298 
299 	nlh_dst = xfrm_nlmsg_put_compat(dst, nlh_src, type);
300 	if (IS_ERR(nlh_dst))
301 		return PTR_ERR(nlh_dst);
302 
303 	attrs = nlmsg_attrdata(nlh_src, xfrm_msg_min[type]);
304 	len = nlmsg_attrlen(nlh_src, xfrm_msg_min[type]);
305 
306 	nla_for_each_attr(nla, attrs, len, remaining) {
307 		int err;
308 
309 		switch (nlh_src->nlmsg_type) {
310 		case XFRM_MSG_NEWSPDINFO:
311 			err = xfrm_nla_cpy(dst, nla, nla_len(nla));
312 			break;
313 		default:
314 			err = xfrm_xlate64_attr(dst, nla);
315 			break;
316 		}
317 		if (err)
318 			return err;
319 	}
320 
321 	nlmsg_end(dst, nlh_dst);
322 
323 	return 0;
324 }
325 
326 static int xfrm_alloc_compat(struct sk_buff *skb, const struct nlmsghdr *nlh_src)
327 {
328 	u16 type = nlh_src->nlmsg_type - XFRM_MSG_BASE;
329 	struct sk_buff *new = NULL;
330 	int err;
331 
332 	if (type >= ARRAY_SIZE(xfrm_msg_min)) {
333 		pr_warn_once("unsupported nlmsg_type %d\n", nlh_src->nlmsg_type);
334 		return -EOPNOTSUPP;
335 	}
336 
337 	if (skb_shinfo(skb)->frag_list == NULL) {
338 		new = alloc_skb(skb->len + skb_tailroom(skb), GFP_ATOMIC);
339 		if (!new)
340 			return -ENOMEM;
341 		skb_shinfo(skb)->frag_list = new;
342 	}
343 
344 	err = xfrm_xlate64(skb_shinfo(skb)->frag_list, nlh_src);
345 	if (err) {
346 		if (new) {
347 			kfree_skb(new);
348 			skb_shinfo(skb)->frag_list = NULL;
349 		}
350 		return err;
351 	}
352 
353 	return 0;
354 }
355 
356 /* Calculates len of translated 64-bit message. */
357 static size_t xfrm_user_rcv_calculate_len64(const struct nlmsghdr *src,
358 					    struct nlattr *attrs[XFRMA_MAX + 1],
359 					    int maxtype)
360 {
361 	size_t len = nlmsg_len(src);
362 
363 	switch (src->nlmsg_type) {
364 	case XFRM_MSG_NEWSA:
365 	case XFRM_MSG_NEWPOLICY:
366 	case XFRM_MSG_ALLOCSPI:
367 	case XFRM_MSG_ACQUIRE:
368 	case XFRM_MSG_UPDPOLICY:
369 	case XFRM_MSG_UPDSA:
370 		len += 4;
371 		break;
372 	case XFRM_MSG_EXPIRE:
373 	case XFRM_MSG_POLEXPIRE:
374 		len += 8;
375 		break;
376 	case XFRM_MSG_NEWSPDINFO:
377 		/* attirbutes are xfrm_spdattr_type_t, not xfrm_attr_type_t */
378 		return len;
379 	default:
380 		break;
381 	}
382 
383 	/* Unexpected for anything, but XFRM_MSG_NEWSPDINFO, please
384 	 * correct both 64=>32-bit and 32=>64-bit translators to copy
385 	 * new attributes.
386 	 */
387 	if (WARN_ON_ONCE(maxtype))
388 		return len;
389 
390 	if (attrs[XFRMA_SA])
391 		len += 4;
392 	if (attrs[XFRMA_POLICY])
393 		len += 4;
394 
395 	/* XXX: some attrs may need to be realigned
396 	 * if !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
397 	 */
398 
399 	return len;
400 }
401 
402 static int xfrm_attr_cpy32(void *dst, size_t *pos, const struct nlattr *src,
403 			   size_t size, int copy_len, int payload)
404 {
405 	struct nlmsghdr *nlmsg = dst;
406 	struct nlattr *nla;
407 
408 	/* xfrm_user_rcv_msg_compat() relies on fact that 32-bit messages
409 	 * have the same len or shorted than 64-bit ones.
410 	 * 32-bit translation that is bigger than 64-bit original is unexpected.
411 	 */
412 	if (WARN_ON_ONCE(copy_len > payload))
413 		copy_len = payload;
414 
415 	if (size - *pos < nla_attr_size(payload))
416 		return -ENOBUFS;
417 
418 	nla = dst + *pos;
419 
420 	memcpy(nla, src, nla_attr_size(copy_len));
421 	nla->nla_len = nla_attr_size(payload);
422 	*pos += nla_attr_size(copy_len);
423 	nlmsg->nlmsg_len += nla->nla_len;
424 
425 	memset(dst + *pos, 0, payload - copy_len);
426 	*pos += payload - copy_len;
427 
428 	return 0;
429 }
430 
431 static int xfrm_xlate32_attr(void *dst, const struct nlattr *nla,
432 			     size_t *pos, size_t size,
433 			     struct netlink_ext_ack *extack)
434 {
435 	int type = nla_type(nla);
436 	u16 pol_len32, pol_len64;
437 	int err;
438 
439 	if (type > XFRMA_MAX) {
440 		BUILD_BUG_ON(XFRMA_MAX != XFRMA_SA_DIR);
441 		NL_SET_ERR_MSG(extack, "Bad attribute");
442 		return -EOPNOTSUPP;
443 	}
444 	type = array_index_nospec(type, XFRMA_MAX + 1);
445 	if (nla_len(nla) < compat_policy[type].len) {
446 		NL_SET_ERR_MSG(extack, "Attribute bad length");
447 		return -EOPNOTSUPP;
448 	}
449 
450 	pol_len32 = compat_policy[type].len;
451 	pol_len64 = xfrma_policy[type].len;
452 
453 	/* XFRMA_SA and XFRMA_POLICY - need to know how-to translate */
454 	if (pol_len32 != pol_len64) {
455 		if (nla_len(nla) != compat_policy[type].len) {
456 			NL_SET_ERR_MSG(extack, "Attribute bad length");
457 			return -EOPNOTSUPP;
458 		}
459 		err = xfrm_attr_cpy32(dst, pos, nla, size, pol_len32, pol_len64);
460 		if (err)
461 			return err;
462 	}
463 
464 	return xfrm_attr_cpy32(dst, pos, nla, size, nla_len(nla), nla_len(nla));
465 }
466 
467 static int xfrm_xlate32(struct nlmsghdr *dst, const struct nlmsghdr *src,
468 			struct nlattr *attrs[XFRMA_MAX+1],
469 			size_t size, u8 type, int maxtype,
470 			struct netlink_ext_ack *extack)
471 {
472 	size_t pos;
473 	int i;
474 
475 	memcpy(dst, src, NLMSG_HDRLEN);
476 	dst->nlmsg_len = NLMSG_HDRLEN + xfrm_msg_min[type];
477 	memset(nlmsg_data(dst), 0, xfrm_msg_min[type]);
478 
479 	switch (src->nlmsg_type) {
480 	/* Compat message has the same layout as native */
481 	case XFRM_MSG_DELSA:
482 	case XFRM_MSG_GETSA:
483 	case XFRM_MSG_DELPOLICY:
484 	case XFRM_MSG_GETPOLICY:
485 	case XFRM_MSG_FLUSHSA:
486 	case XFRM_MSG_FLUSHPOLICY:
487 	case XFRM_MSG_NEWAE:
488 	case XFRM_MSG_GETAE:
489 	case XFRM_MSG_REPORT:
490 	case XFRM_MSG_MIGRATE:
491 	case XFRM_MSG_NEWSADINFO:
492 	case XFRM_MSG_GETSADINFO:
493 	case XFRM_MSG_NEWSPDINFO:
494 	case XFRM_MSG_GETSPDINFO:
495 	case XFRM_MSG_MAPPING:
496 		memcpy(nlmsg_data(dst), nlmsg_data(src), compat_msg_min[type]);
497 		break;
498 	/* 4 byte alignment for trailing u64 on native, but not on compat */
499 	case XFRM_MSG_NEWSA:
500 	case XFRM_MSG_NEWPOLICY:
501 	case XFRM_MSG_UPDSA:
502 	case XFRM_MSG_UPDPOLICY:
503 		memcpy(nlmsg_data(dst), nlmsg_data(src), compat_msg_min[type]);
504 		break;
505 	case XFRM_MSG_EXPIRE: {
506 		const struct compat_xfrm_user_expire *src_ue = nlmsg_data(src);
507 		struct xfrm_user_expire *dst_ue = nlmsg_data(dst);
508 
509 		/* compat_xfrm_user_expire has 4-byte smaller state */
510 		memcpy(dst_ue, src_ue, sizeof(src_ue->state));
511 		dst_ue->hard = src_ue->hard;
512 		break;
513 	}
514 	case XFRM_MSG_ACQUIRE: {
515 		const struct compat_xfrm_user_acquire *src_ua = nlmsg_data(src);
516 		struct xfrm_user_acquire *dst_ua = nlmsg_data(dst);
517 
518 		memcpy(dst_ua, src_ua, offsetof(struct compat_xfrm_user_acquire, aalgos));
519 		dst_ua->aalgos = src_ua->aalgos;
520 		dst_ua->ealgos = src_ua->ealgos;
521 		dst_ua->calgos = src_ua->calgos;
522 		dst_ua->seq    = src_ua->seq;
523 		break;
524 	}
525 	case XFRM_MSG_POLEXPIRE: {
526 		const struct compat_xfrm_user_polexpire *src_upe = nlmsg_data(src);
527 		struct xfrm_user_polexpire *dst_upe = nlmsg_data(dst);
528 
529 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
530 		memcpy(dst_upe, src_upe, sizeof(src_upe->pol));
531 		dst_upe->hard = src_upe->hard;
532 		break;
533 	}
534 	case XFRM_MSG_ALLOCSPI: {
535 		const struct compat_xfrm_userspi_info *src_usi = nlmsg_data(src);
536 		struct xfrm_userspi_info *dst_usi = nlmsg_data(dst);
537 
538 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
539 		memcpy(dst_usi, src_usi, sizeof(src_usi->info));
540 		dst_usi->min = src_usi->min;
541 		dst_usi->max = src_usi->max;
542 		break;
543 	}
544 	default:
545 		NL_SET_ERR_MSG(extack, "Unsupported message type");
546 		return -EOPNOTSUPP;
547 	}
548 	pos = dst->nlmsg_len;
549 
550 	if (maxtype) {
551 		/* attirbutes are xfrm_spdattr_type_t, not xfrm_attr_type_t */
552 		WARN_ON_ONCE(src->nlmsg_type != XFRM_MSG_NEWSPDINFO);
553 
554 		for (i = 1; i <= maxtype; i++) {
555 			int err;
556 
557 			if (!attrs[i])
558 				continue;
559 
560 			/* just copy - no need for translation */
561 			err = xfrm_attr_cpy32(dst, &pos, attrs[i], size,
562 					nla_len(attrs[i]), nla_len(attrs[i]));
563 			if (err)
564 				return err;
565 		}
566 		return 0;
567 	}
568 
569 	for (i = 1; i < XFRMA_MAX + 1; i++) {
570 		int err;
571 
572 		if (i == XFRMA_PAD)
573 			continue;
574 
575 		if (!attrs[i])
576 			continue;
577 
578 		err = xfrm_xlate32_attr(dst, attrs[i], &pos, size, extack);
579 		if (err)
580 			return err;
581 	}
582 
583 	return 0;
584 }
585 
586 static struct nlmsghdr *xfrm_user_rcv_msg_compat(const struct nlmsghdr *h32,
587 			int maxtype, const struct nla_policy *policy,
588 			struct netlink_ext_ack *extack)
589 {
590 	/* netlink_rcv_skb() checks if a message has full (struct nlmsghdr) */
591 	u16 type = h32->nlmsg_type - XFRM_MSG_BASE;
592 	struct nlattr *attrs[XFRMA_MAX+1];
593 	struct nlmsghdr *h64;
594 	size_t len;
595 	int err;
596 
597 	BUILD_BUG_ON(ARRAY_SIZE(xfrm_msg_min) != ARRAY_SIZE(compat_msg_min));
598 
599 	if (type >= ARRAY_SIZE(xfrm_msg_min))
600 		return ERR_PTR(-EINVAL);
601 
602 	/* Don't call parse: the message might have only nlmsg header */
603 	if ((h32->nlmsg_type == XFRM_MSG_GETSA ||
604 	     h32->nlmsg_type == XFRM_MSG_GETPOLICY) &&
605 	    (h32->nlmsg_flags & NLM_F_DUMP))
606 		return NULL;
607 
608 	err = nlmsg_parse_deprecated(h32, compat_msg_min[type], attrs,
609 			maxtype ? : XFRMA_MAX, policy ? : compat_policy, extack);
610 	if (err < 0)
611 		return ERR_PTR(err);
612 
613 	len = xfrm_user_rcv_calculate_len64(h32, attrs, maxtype);
614 	/* The message doesn't need translation */
615 	if (len == nlmsg_len(h32))
616 		return NULL;
617 
618 	len += NLMSG_HDRLEN;
619 	h64 = kvmalloc(len, GFP_KERNEL);
620 	if (!h64)
621 		return ERR_PTR(-ENOMEM);
622 
623 	err = xfrm_xlate32(h64, h32, attrs, len, type, maxtype, extack);
624 	if (err < 0) {
625 		kvfree(h64);
626 		return ERR_PTR(err);
627 	}
628 
629 	return h64;
630 }
631 
632 static int xfrm_user_policy_compat(u8 **pdata32, int optlen)
633 {
634 	struct compat_xfrm_userpolicy_info *p = (void *)*pdata32;
635 	u8 *src_templates, *dst_templates;
636 	u8 *data64;
637 
638 	if (optlen < sizeof(*p))
639 		return -EINVAL;
640 
641 	data64 = kmalloc_track_caller(optlen + 4, GFP_USER | __GFP_NOWARN);
642 	if (!data64)
643 		return -ENOMEM;
644 
645 	memcpy(data64, *pdata32, sizeof(*p));
646 	memset(data64 + sizeof(*p), 0, 4);
647 
648 	src_templates = *pdata32 + sizeof(*p);
649 	dst_templates = data64 + sizeof(*p) + 4;
650 	memcpy(dst_templates, src_templates, optlen - sizeof(*p));
651 
652 	kfree(*pdata32);
653 	*pdata32 = data64;
654 	return 0;
655 }
656 
657 static struct xfrm_translator xfrm_translator = {
658 	.owner				= THIS_MODULE,
659 	.alloc_compat			= xfrm_alloc_compat,
660 	.rcv_msg_compat			= xfrm_user_rcv_msg_compat,
661 	.xlate_user_policy_sockptr	= xfrm_user_policy_compat,
662 };
663 
664 static int __init xfrm_compat_init(void)
665 {
666 	return xfrm_register_translator(&xfrm_translator);
667 }
668 
669 static void __exit xfrm_compat_exit(void)
670 {
671 	xfrm_unregister_translator(&xfrm_translator);
672 }
673 
674 module_init(xfrm_compat_init);
675 module_exit(xfrm_compat_exit);
676 MODULE_LICENSE("GPL");
677 MODULE_AUTHOR("Dmitry Safonov");
678 MODULE_DESCRIPTION("XFRM 32-bit compatibility layer");
679