xref: /openbmc/linux/net/xfrm/xfrm_compat.c (revision 79e790ff)
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/xfrm.h>
9 #include <net/xfrm.h>
10 
11 struct compat_xfrm_lifetime_cfg {
12 	compat_u64 soft_byte_limit, hard_byte_limit;
13 	compat_u64 soft_packet_limit, hard_packet_limit;
14 	compat_u64 soft_add_expires_seconds, hard_add_expires_seconds;
15 	compat_u64 soft_use_expires_seconds, hard_use_expires_seconds;
16 }; /* same size on 32bit, but only 4 byte alignment required */
17 
18 struct compat_xfrm_lifetime_cur {
19 	compat_u64 bytes, packets, add_time, use_time;
20 }; /* same size on 32bit, but only 4 byte alignment required */
21 
22 struct compat_xfrm_userpolicy_info {
23 	struct xfrm_selector sel;
24 	struct compat_xfrm_lifetime_cfg lft;
25 	struct compat_xfrm_lifetime_cur curlft;
26 	__u32 priority, index;
27 	u8 dir, action, flags, share;
28 	/* 4 bytes additional padding on 64bit */
29 };
30 
31 struct compat_xfrm_usersa_info {
32 	struct xfrm_selector sel;
33 	struct xfrm_id id;
34 	xfrm_address_t saddr;
35 	struct compat_xfrm_lifetime_cfg lft;
36 	struct compat_xfrm_lifetime_cur curlft;
37 	struct xfrm_stats stats;
38 	__u32 seq, reqid;
39 	u16 family;
40 	u8 mode, replay_window, flags;
41 	/* 4 bytes additional padding on 64bit */
42 };
43 
44 struct compat_xfrm_user_acquire {
45 	struct xfrm_id id;
46 	xfrm_address_t saddr;
47 	struct xfrm_selector sel;
48 	struct compat_xfrm_userpolicy_info policy;
49 	/* 4 bytes additional padding on 64bit */
50 	__u32 aalgos, ealgos, calgos, seq;
51 };
52 
53 struct compat_xfrm_userspi_info {
54 	struct compat_xfrm_usersa_info info;
55 	/* 4 bytes additional padding on 64bit */
56 	__u32 min, max;
57 };
58 
59 struct compat_xfrm_user_expire {
60 	struct compat_xfrm_usersa_info state;
61 	/* 8 bytes additional padding on 64bit */
62 	u8 hard;
63 };
64 
65 struct compat_xfrm_user_polexpire {
66 	struct compat_xfrm_userpolicy_info pol;
67 	/* 8 bytes additional padding on 64bit */
68 	u8 hard;
69 };
70 
71 #define XMSGSIZE(type) sizeof(struct type)
72 
73 static const int compat_msg_min[XFRM_NR_MSGTYPES] = {
74 	[XFRM_MSG_NEWSA       - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_usersa_info),
75 	[XFRM_MSG_DELSA       - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_id),
76 	[XFRM_MSG_GETSA       - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_id),
77 	[XFRM_MSG_NEWPOLICY   - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_userpolicy_info),
78 	[XFRM_MSG_DELPOLICY   - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_id),
79 	[XFRM_MSG_GETPOLICY   - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_id),
80 	[XFRM_MSG_ALLOCSPI    - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_userspi_info),
81 	[XFRM_MSG_ACQUIRE     - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_user_acquire),
82 	[XFRM_MSG_EXPIRE      - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_user_expire),
83 	[XFRM_MSG_UPDPOLICY   - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_userpolicy_info),
84 	[XFRM_MSG_UPDSA       - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_usersa_info),
85 	[XFRM_MSG_POLEXPIRE   - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_user_polexpire),
86 	[XFRM_MSG_FLUSHSA     - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_flush),
87 	[XFRM_MSG_FLUSHPOLICY - XFRM_MSG_BASE] = 0,
88 	[XFRM_MSG_NEWAE       - XFRM_MSG_BASE] = XMSGSIZE(xfrm_aevent_id),
89 	[XFRM_MSG_GETAE       - XFRM_MSG_BASE] = XMSGSIZE(xfrm_aevent_id),
90 	[XFRM_MSG_REPORT      - XFRM_MSG_BASE] = XMSGSIZE(xfrm_user_report),
91 	[XFRM_MSG_MIGRATE     - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_id),
92 	[XFRM_MSG_NEWSADINFO  - XFRM_MSG_BASE] = sizeof(u32),
93 	[XFRM_MSG_GETSADINFO  - XFRM_MSG_BASE] = sizeof(u32),
94 	[XFRM_MSG_NEWSPDINFO  - XFRM_MSG_BASE] = sizeof(u32),
95 	[XFRM_MSG_GETSPDINFO  - XFRM_MSG_BASE] = sizeof(u32),
96 	[XFRM_MSG_MAPPING     - XFRM_MSG_BASE] = XMSGSIZE(xfrm_user_mapping)
97 };
98 
99 static const struct nla_policy compat_policy[XFRMA_MAX+1] = {
100 	[XFRMA_SA]		= { .len = XMSGSIZE(compat_xfrm_usersa_info)},
101 	[XFRMA_POLICY]		= { .len = XMSGSIZE(compat_xfrm_userpolicy_info)},
102 	[XFRMA_LASTUSED]	= { .type = NLA_U64},
103 	[XFRMA_ALG_AUTH_TRUNC]	= { .len = sizeof(struct xfrm_algo_auth)},
104 	[XFRMA_ALG_AEAD]	= { .len = sizeof(struct xfrm_algo_aead) },
105 	[XFRMA_ALG_AUTH]	= { .len = sizeof(struct xfrm_algo) },
106 	[XFRMA_ALG_CRYPT]	= { .len = sizeof(struct xfrm_algo) },
107 	[XFRMA_ALG_COMP]	= { .len = sizeof(struct xfrm_algo) },
108 	[XFRMA_ENCAP]		= { .len = sizeof(struct xfrm_encap_tmpl) },
109 	[XFRMA_TMPL]		= { .len = sizeof(struct xfrm_user_tmpl) },
110 	[XFRMA_SEC_CTX]		= { .len = sizeof(struct xfrm_sec_ctx) },
111 	[XFRMA_LTIME_VAL]	= { .len = sizeof(struct xfrm_lifetime_cur) },
112 	[XFRMA_REPLAY_VAL]	= { .len = sizeof(struct xfrm_replay_state) },
113 	[XFRMA_REPLAY_THRESH]	= { .type = NLA_U32 },
114 	[XFRMA_ETIMER_THRESH]	= { .type = NLA_U32 },
115 	[XFRMA_SRCADDR]		= { .len = sizeof(xfrm_address_t) },
116 	[XFRMA_COADDR]		= { .len = sizeof(xfrm_address_t) },
117 	[XFRMA_POLICY_TYPE]	= { .len = sizeof(struct xfrm_userpolicy_type)},
118 	[XFRMA_MIGRATE]		= { .len = sizeof(struct xfrm_user_migrate) },
119 	[XFRMA_KMADDRESS]	= { .len = sizeof(struct xfrm_user_kmaddress) },
120 	[XFRMA_MARK]		= { .len = sizeof(struct xfrm_mark) },
121 	[XFRMA_TFCPAD]		= { .type = NLA_U32 },
122 	[XFRMA_REPLAY_ESN_VAL]	= { .len = sizeof(struct xfrm_replay_state_esn) },
123 	[XFRMA_SA_EXTRA_FLAGS]	= { .type = NLA_U32 },
124 	[XFRMA_PROTO]		= { .type = NLA_U8 },
125 	[XFRMA_ADDRESS_FILTER]	= { .len = sizeof(struct xfrm_address_filter) },
126 	[XFRMA_OFFLOAD_DEV]	= { .len = sizeof(struct xfrm_user_offload) },
127 	[XFRMA_SET_MARK]	= { .type = NLA_U32 },
128 	[XFRMA_SET_MARK_MASK]	= { .type = NLA_U32 },
129 	[XFRMA_IF_ID]		= { .type = NLA_U32 },
130 };
131 
132 static struct nlmsghdr *xfrm_nlmsg_put_compat(struct sk_buff *skb,
133 			const struct nlmsghdr *nlh_src, u16 type)
134 {
135 	int payload = compat_msg_min[type];
136 	int src_len = xfrm_msg_min[type];
137 	struct nlmsghdr *nlh_dst;
138 
139 	/* Compat messages are shorter or equal to native (+padding) */
140 	if (WARN_ON_ONCE(src_len < payload))
141 		return ERR_PTR(-EMSGSIZE);
142 
143 	nlh_dst = nlmsg_put(skb, nlh_src->nlmsg_pid, nlh_src->nlmsg_seq,
144 			    nlh_src->nlmsg_type, payload, nlh_src->nlmsg_flags);
145 	if (!nlh_dst)
146 		return ERR_PTR(-EMSGSIZE);
147 
148 	memset(nlmsg_data(nlh_dst), 0, payload);
149 
150 	switch (nlh_src->nlmsg_type) {
151 	/* Compat message has the same layout as native */
152 	case XFRM_MSG_DELSA:
153 	case XFRM_MSG_DELPOLICY:
154 	case XFRM_MSG_FLUSHSA:
155 	case XFRM_MSG_FLUSHPOLICY:
156 	case XFRM_MSG_NEWAE:
157 	case XFRM_MSG_REPORT:
158 	case XFRM_MSG_MIGRATE:
159 	case XFRM_MSG_NEWSADINFO:
160 	case XFRM_MSG_NEWSPDINFO:
161 	case XFRM_MSG_MAPPING:
162 		WARN_ON_ONCE(src_len != payload);
163 		memcpy(nlmsg_data(nlh_dst), nlmsg_data(nlh_src), src_len);
164 		break;
165 	/* 4 byte alignment for trailing u64 on native, but not on compat */
166 	case XFRM_MSG_NEWSA:
167 	case XFRM_MSG_NEWPOLICY:
168 	case XFRM_MSG_UPDSA:
169 	case XFRM_MSG_UPDPOLICY:
170 		WARN_ON_ONCE(src_len != payload + 4);
171 		memcpy(nlmsg_data(nlh_dst), nlmsg_data(nlh_src), payload);
172 		break;
173 	case XFRM_MSG_EXPIRE: {
174 		const struct xfrm_user_expire *src_ue  = nlmsg_data(nlh_src);
175 		struct compat_xfrm_user_expire *dst_ue = nlmsg_data(nlh_dst);
176 
177 		/* compat_xfrm_user_expire has 4-byte smaller state */
178 		memcpy(dst_ue, src_ue, sizeof(dst_ue->state));
179 		dst_ue->hard = src_ue->hard;
180 		break;
181 	}
182 	case XFRM_MSG_ACQUIRE: {
183 		const struct xfrm_user_acquire *src_ua  = nlmsg_data(nlh_src);
184 		struct compat_xfrm_user_acquire *dst_ua = nlmsg_data(nlh_dst);
185 
186 		memcpy(dst_ua, src_ua, offsetof(struct compat_xfrm_user_acquire, aalgos));
187 		dst_ua->aalgos = src_ua->aalgos;
188 		dst_ua->ealgos = src_ua->ealgos;
189 		dst_ua->calgos = src_ua->calgos;
190 		dst_ua->seq    = src_ua->seq;
191 		break;
192 	}
193 	case XFRM_MSG_POLEXPIRE: {
194 		const struct xfrm_user_polexpire *src_upe  = nlmsg_data(nlh_src);
195 		struct compat_xfrm_user_polexpire *dst_upe = nlmsg_data(nlh_dst);
196 
197 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
198 		memcpy(dst_upe, src_upe, sizeof(dst_upe->pol));
199 		dst_upe->hard = src_upe->hard;
200 		break;
201 	}
202 	case XFRM_MSG_ALLOCSPI: {
203 		const struct xfrm_userspi_info *src_usi = nlmsg_data(nlh_src);
204 		struct compat_xfrm_userspi_info *dst_usi = nlmsg_data(nlh_dst);
205 
206 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
207 		memcpy(dst_usi, src_usi, sizeof(src_usi->info));
208 		dst_usi->min = src_usi->min;
209 		dst_usi->max = src_usi->max;
210 		break;
211 	}
212 	/* Not being sent by kernel */
213 	case XFRM_MSG_GETSA:
214 	case XFRM_MSG_GETPOLICY:
215 	case XFRM_MSG_GETAE:
216 	case XFRM_MSG_GETSADINFO:
217 	case XFRM_MSG_GETSPDINFO:
218 	default:
219 		pr_warn_once("unsupported nlmsg_type %d\n", nlh_src->nlmsg_type);
220 		return ERR_PTR(-EOPNOTSUPP);
221 	}
222 
223 	return nlh_dst;
224 }
225 
226 static int xfrm_nla_cpy(struct sk_buff *dst, const struct nlattr *src, int len)
227 {
228 	return nla_put(dst, src->nla_type, len, nla_data(src));
229 }
230 
231 static int xfrm_xlate64_attr(struct sk_buff *dst, const struct nlattr *src)
232 {
233 	switch (src->nla_type) {
234 	case XFRMA_PAD:
235 		/* Ignore */
236 		return 0;
237 	case XFRMA_UNSPEC:
238 	case XFRMA_ALG_AUTH:
239 	case XFRMA_ALG_CRYPT:
240 	case XFRMA_ALG_COMP:
241 	case XFRMA_ENCAP:
242 	case XFRMA_TMPL:
243 		return xfrm_nla_cpy(dst, src, nla_len(src));
244 	case XFRMA_SA:
245 		return xfrm_nla_cpy(dst, src, XMSGSIZE(compat_xfrm_usersa_info));
246 	case XFRMA_POLICY:
247 		return xfrm_nla_cpy(dst, src, XMSGSIZE(compat_xfrm_userpolicy_info));
248 	case XFRMA_SEC_CTX:
249 		return xfrm_nla_cpy(dst, src, nla_len(src));
250 	case XFRMA_LTIME_VAL:
251 		return nla_put_64bit(dst, src->nla_type, nla_len(src),
252 			nla_data(src), XFRMA_PAD);
253 	case XFRMA_REPLAY_VAL:
254 	case XFRMA_REPLAY_THRESH:
255 	case XFRMA_ETIMER_THRESH:
256 	case XFRMA_SRCADDR:
257 	case XFRMA_COADDR:
258 		return xfrm_nla_cpy(dst, src, nla_len(src));
259 	case XFRMA_LASTUSED:
260 		return nla_put_64bit(dst, src->nla_type, nla_len(src),
261 			nla_data(src), XFRMA_PAD);
262 	case XFRMA_POLICY_TYPE:
263 	case XFRMA_MIGRATE:
264 	case XFRMA_ALG_AEAD:
265 	case XFRMA_KMADDRESS:
266 	case XFRMA_ALG_AUTH_TRUNC:
267 	case XFRMA_MARK:
268 	case XFRMA_TFCPAD:
269 	case XFRMA_REPLAY_ESN_VAL:
270 	case XFRMA_SA_EXTRA_FLAGS:
271 	case XFRMA_PROTO:
272 	case XFRMA_ADDRESS_FILTER:
273 	case XFRMA_OFFLOAD_DEV:
274 	case XFRMA_SET_MARK:
275 	case XFRMA_SET_MARK_MASK:
276 	case XFRMA_IF_ID:
277 		return xfrm_nla_cpy(dst, src, nla_len(src));
278 	default:
279 		BUILD_BUG_ON(XFRMA_MAX != XFRMA_IF_ID);
280 		pr_warn_once("unsupported nla_type %d\n", src->nla_type);
281 		return -EOPNOTSUPP;
282 	}
283 }
284 
285 /* Take kernel-built (64bit layout) and create 32bit layout for userspace */
286 static int xfrm_xlate64(struct sk_buff *dst, const struct nlmsghdr *nlh_src)
287 {
288 	u16 type = nlh_src->nlmsg_type - XFRM_MSG_BASE;
289 	const struct nlattr *nla, *attrs;
290 	struct nlmsghdr *nlh_dst;
291 	int len, remaining;
292 
293 	nlh_dst = xfrm_nlmsg_put_compat(dst, nlh_src, type);
294 	if (IS_ERR(nlh_dst))
295 		return PTR_ERR(nlh_dst);
296 
297 	attrs = nlmsg_attrdata(nlh_src, xfrm_msg_min[type]);
298 	len = nlmsg_attrlen(nlh_src, xfrm_msg_min[type]);
299 
300 	nla_for_each_attr(nla, attrs, len, remaining) {
301 		int err = xfrm_xlate64_attr(dst, nla);
302 
303 		if (err)
304 			return err;
305 	}
306 
307 	nlmsg_end(dst, nlh_dst);
308 
309 	return 0;
310 }
311 
312 static int xfrm_alloc_compat(struct sk_buff *skb, const struct nlmsghdr *nlh_src)
313 {
314 	u16 type = nlh_src->nlmsg_type - XFRM_MSG_BASE;
315 	struct sk_buff *new = NULL;
316 	int err;
317 
318 	if (type >= ARRAY_SIZE(xfrm_msg_min)) {
319 		pr_warn_once("unsupported nlmsg_type %d\n", nlh_src->nlmsg_type);
320 		return -EOPNOTSUPP;
321 	}
322 
323 	if (skb_shinfo(skb)->frag_list == NULL) {
324 		new = alloc_skb(skb->len + skb_tailroom(skb), GFP_ATOMIC);
325 		if (!new)
326 			return -ENOMEM;
327 		skb_shinfo(skb)->frag_list = new;
328 	}
329 
330 	err = xfrm_xlate64(skb_shinfo(skb)->frag_list, nlh_src);
331 	if (err) {
332 		if (new) {
333 			kfree_skb(new);
334 			skb_shinfo(skb)->frag_list = NULL;
335 		}
336 		return err;
337 	}
338 
339 	return 0;
340 }
341 
342 /* Calculates len of translated 64-bit message. */
343 static size_t xfrm_user_rcv_calculate_len64(const struct nlmsghdr *src,
344 					    struct nlattr *attrs[XFRMA_MAX+1])
345 {
346 	size_t len = nlmsg_len(src);
347 
348 	switch (src->nlmsg_type) {
349 	case XFRM_MSG_NEWSA:
350 	case XFRM_MSG_NEWPOLICY:
351 	case XFRM_MSG_ALLOCSPI:
352 	case XFRM_MSG_ACQUIRE:
353 	case XFRM_MSG_UPDPOLICY:
354 	case XFRM_MSG_UPDSA:
355 		len += 4;
356 		break;
357 	case XFRM_MSG_EXPIRE:
358 	case XFRM_MSG_POLEXPIRE:
359 		len += 8;
360 		break;
361 	default:
362 		break;
363 	}
364 
365 	if (attrs[XFRMA_SA])
366 		len += 4;
367 	if (attrs[XFRMA_POLICY])
368 		len += 4;
369 
370 	/* XXX: some attrs may need to be realigned
371 	 * if !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
372 	 */
373 
374 	return len;
375 }
376 
377 static int xfrm_attr_cpy32(void *dst, size_t *pos, const struct nlattr *src,
378 			   size_t size, int copy_len, int payload)
379 {
380 	struct nlmsghdr *nlmsg = dst;
381 	struct nlattr *nla;
382 
383 	/* xfrm_user_rcv_msg_compat() relies on fact that 32-bit messages
384 	 * have the same len or shorted than 64-bit ones.
385 	 * 32-bit translation that is bigger than 64-bit original is unexpected.
386 	 */
387 	if (WARN_ON_ONCE(copy_len > payload))
388 		copy_len = payload;
389 
390 	if (size - *pos < nla_attr_size(payload))
391 		return -ENOBUFS;
392 
393 	nla = dst + *pos;
394 
395 	memcpy(nla, src, nla_attr_size(copy_len));
396 	nla->nla_len = nla_attr_size(payload);
397 	*pos += nla_attr_size(copy_len);
398 	nlmsg->nlmsg_len += nla->nla_len;
399 
400 	memset(dst + *pos, 0, payload - copy_len);
401 	*pos += payload - copy_len;
402 
403 	return 0;
404 }
405 
406 static int xfrm_xlate32_attr(void *dst, const struct nlattr *nla,
407 			     size_t *pos, size_t size,
408 			     struct netlink_ext_ack *extack)
409 {
410 	int type = nla_type(nla);
411 	u16 pol_len32, pol_len64;
412 	int err;
413 
414 	if (type > XFRMA_MAX) {
415 		BUILD_BUG_ON(XFRMA_MAX != XFRMA_IF_ID);
416 		NL_SET_ERR_MSG(extack, "Bad attribute");
417 		return -EOPNOTSUPP;
418 	}
419 	if (nla_len(nla) < compat_policy[type].len) {
420 		NL_SET_ERR_MSG(extack, "Attribute bad length");
421 		return -EOPNOTSUPP;
422 	}
423 
424 	pol_len32 = compat_policy[type].len;
425 	pol_len64 = xfrma_policy[type].len;
426 
427 	/* XFRMA_SA and XFRMA_POLICY - need to know how-to translate */
428 	if (pol_len32 != pol_len64) {
429 		if (nla_len(nla) != compat_policy[type].len) {
430 			NL_SET_ERR_MSG(extack, "Attribute bad length");
431 			return -EOPNOTSUPP;
432 		}
433 		err = xfrm_attr_cpy32(dst, pos, nla, size, pol_len32, pol_len64);
434 		if (err)
435 			return err;
436 	}
437 
438 	return xfrm_attr_cpy32(dst, pos, nla, size, nla_len(nla), nla_len(nla));
439 }
440 
441 static int xfrm_xlate32(struct nlmsghdr *dst, const struct nlmsghdr *src,
442 			struct nlattr *attrs[XFRMA_MAX+1],
443 			size_t size, u8 type, struct netlink_ext_ack *extack)
444 {
445 	size_t pos;
446 	int i;
447 
448 	memcpy(dst, src, NLMSG_HDRLEN);
449 	dst->nlmsg_len = NLMSG_HDRLEN + xfrm_msg_min[type];
450 	memset(nlmsg_data(dst), 0, xfrm_msg_min[type]);
451 
452 	switch (src->nlmsg_type) {
453 	/* Compat message has the same layout as native */
454 	case XFRM_MSG_DELSA:
455 	case XFRM_MSG_GETSA:
456 	case XFRM_MSG_DELPOLICY:
457 	case XFRM_MSG_GETPOLICY:
458 	case XFRM_MSG_FLUSHSA:
459 	case XFRM_MSG_FLUSHPOLICY:
460 	case XFRM_MSG_NEWAE:
461 	case XFRM_MSG_GETAE:
462 	case XFRM_MSG_REPORT:
463 	case XFRM_MSG_MIGRATE:
464 	case XFRM_MSG_NEWSADINFO:
465 	case XFRM_MSG_GETSADINFO:
466 	case XFRM_MSG_NEWSPDINFO:
467 	case XFRM_MSG_GETSPDINFO:
468 	case XFRM_MSG_MAPPING:
469 		memcpy(nlmsg_data(dst), nlmsg_data(src), compat_msg_min[type]);
470 		break;
471 	/* 4 byte alignment for trailing u64 on native, but not on compat */
472 	case XFRM_MSG_NEWSA:
473 	case XFRM_MSG_NEWPOLICY:
474 	case XFRM_MSG_UPDSA:
475 	case XFRM_MSG_UPDPOLICY:
476 		memcpy(nlmsg_data(dst), nlmsg_data(src), compat_msg_min[type]);
477 		break;
478 	case XFRM_MSG_EXPIRE: {
479 		const struct compat_xfrm_user_expire *src_ue = nlmsg_data(src);
480 		struct xfrm_user_expire *dst_ue = nlmsg_data(dst);
481 
482 		/* compat_xfrm_user_expire has 4-byte smaller state */
483 		memcpy(dst_ue, src_ue, sizeof(src_ue->state));
484 		dst_ue->hard = src_ue->hard;
485 		break;
486 	}
487 	case XFRM_MSG_ACQUIRE: {
488 		const struct compat_xfrm_user_acquire *src_ua = nlmsg_data(src);
489 		struct xfrm_user_acquire *dst_ua = nlmsg_data(dst);
490 
491 		memcpy(dst_ua, src_ua, offsetof(struct compat_xfrm_user_acquire, aalgos));
492 		dst_ua->aalgos = src_ua->aalgos;
493 		dst_ua->ealgos = src_ua->ealgos;
494 		dst_ua->calgos = src_ua->calgos;
495 		dst_ua->seq    = src_ua->seq;
496 		break;
497 	}
498 	case XFRM_MSG_POLEXPIRE: {
499 		const struct compat_xfrm_user_polexpire *src_upe = nlmsg_data(src);
500 		struct xfrm_user_polexpire *dst_upe = nlmsg_data(dst);
501 
502 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
503 		memcpy(dst_upe, src_upe, sizeof(src_upe->pol));
504 		dst_upe->hard = src_upe->hard;
505 		break;
506 	}
507 	case XFRM_MSG_ALLOCSPI: {
508 		const struct compat_xfrm_userspi_info *src_usi = nlmsg_data(src);
509 		struct xfrm_userspi_info *dst_usi = nlmsg_data(dst);
510 
511 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
512 		memcpy(dst_usi, src_usi, sizeof(src_usi->info));
513 		dst_usi->min = src_usi->min;
514 		dst_usi->max = src_usi->max;
515 		break;
516 	}
517 	default:
518 		NL_SET_ERR_MSG(extack, "Unsupported message type");
519 		return -EOPNOTSUPP;
520 	}
521 	pos = dst->nlmsg_len;
522 
523 	for (i = 1; i < XFRMA_MAX + 1; i++) {
524 		int err;
525 
526 		if (i == XFRMA_PAD)
527 			continue;
528 
529 		if (!attrs[i])
530 			continue;
531 
532 		err = xfrm_xlate32_attr(dst, attrs[i], &pos, size, extack);
533 		if (err)
534 			return err;
535 	}
536 
537 	return 0;
538 }
539 
540 static struct nlmsghdr *xfrm_user_rcv_msg_compat(const struct nlmsghdr *h32,
541 			int maxtype, const struct nla_policy *policy,
542 			struct netlink_ext_ack *extack)
543 {
544 	/* netlink_rcv_skb() checks if a message has full (struct nlmsghdr) */
545 	u16 type = h32->nlmsg_type - XFRM_MSG_BASE;
546 	struct nlattr *attrs[XFRMA_MAX+1];
547 	struct nlmsghdr *h64;
548 	size_t len;
549 	int err;
550 
551 	BUILD_BUG_ON(ARRAY_SIZE(xfrm_msg_min) != ARRAY_SIZE(compat_msg_min));
552 
553 	if (type >= ARRAY_SIZE(xfrm_msg_min))
554 		return ERR_PTR(-EINVAL);
555 
556 	/* Don't call parse: the message might have only nlmsg header */
557 	if ((h32->nlmsg_type == XFRM_MSG_GETSA ||
558 	     h32->nlmsg_type == XFRM_MSG_GETPOLICY) &&
559 	    (h32->nlmsg_flags & NLM_F_DUMP))
560 		return NULL;
561 
562 	err = nlmsg_parse_deprecated(h32, compat_msg_min[type], attrs,
563 			maxtype ? : XFRMA_MAX, policy ? : compat_policy, extack);
564 	if (err < 0)
565 		return ERR_PTR(err);
566 
567 	len = xfrm_user_rcv_calculate_len64(h32, attrs);
568 	/* The message doesn't need translation */
569 	if (len == nlmsg_len(h32))
570 		return NULL;
571 
572 	len += NLMSG_HDRLEN;
573 	h64 = kvmalloc(len, GFP_KERNEL);
574 	if (!h64)
575 		return ERR_PTR(-ENOMEM);
576 
577 	err = xfrm_xlate32(h64, h32, attrs, len, type, extack);
578 	if (err < 0) {
579 		kvfree(h64);
580 		return ERR_PTR(err);
581 	}
582 
583 	return h64;
584 }
585 
586 static int xfrm_user_policy_compat(u8 **pdata32, int optlen)
587 {
588 	struct compat_xfrm_userpolicy_info *p = (void *)*pdata32;
589 	u8 *src_templates, *dst_templates;
590 	u8 *data64;
591 
592 	if (optlen < sizeof(*p))
593 		return -EINVAL;
594 
595 	data64 = kmalloc_track_caller(optlen + 4, GFP_USER | __GFP_NOWARN);
596 	if (!data64)
597 		return -ENOMEM;
598 
599 	memcpy(data64, *pdata32, sizeof(*p));
600 	memset(data64 + sizeof(*p), 0, 4);
601 
602 	src_templates = *pdata32 + sizeof(*p);
603 	dst_templates = data64 + sizeof(*p) + 4;
604 	memcpy(dst_templates, src_templates, optlen - sizeof(*p));
605 
606 	kfree(*pdata32);
607 	*pdata32 = data64;
608 	return 0;
609 }
610 
611 static struct xfrm_translator xfrm_translator = {
612 	.owner				= THIS_MODULE,
613 	.alloc_compat			= xfrm_alloc_compat,
614 	.rcv_msg_compat			= xfrm_user_rcv_msg_compat,
615 	.xlate_user_policy_sockptr	= xfrm_user_policy_compat,
616 };
617 
618 static int __init xfrm_compat_init(void)
619 {
620 	return xfrm_register_translator(&xfrm_translator);
621 }
622 
623 static void __exit xfrm_compat_exit(void)
624 {
625 	xfrm_unregister_translator(&xfrm_translator);
626 }
627 
628 module_init(xfrm_compat_init);
629 module_exit(xfrm_compat_exit);
630 MODULE_LICENSE("GPL");
631 MODULE_AUTHOR("Dmitry Safonov");
632 MODULE_DESCRIPTION("XFRM 32-bit compatibility layer");
633