xref: /linux/net/xfrm/xfrm_compat.c (revision eec8359f0797ef87c6ef6cbed6de08b02073b833)
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 	[XFRMA_NAT_KEEPALIVE_INTERVAL]	= { .type = NLA_U32 },
135 	[XFRMA_SA_PCPU]		= { .type = NLA_U32 },
136 };
137 
138 static struct nlmsghdr *xfrm_nlmsg_put_compat(struct sk_buff *skb,
139 			const struct nlmsghdr *nlh_src, u16 type)
140 {
141 	int payload = compat_msg_min[type];
142 	int src_len = xfrm_msg_min[type];
143 	struct nlmsghdr *nlh_dst;
144 
145 	/* Compat messages are shorter or equal to native (+padding) */
146 	if (WARN_ON_ONCE(src_len < payload))
147 		return ERR_PTR(-EMSGSIZE);
148 
149 	nlh_dst = nlmsg_put(skb, nlh_src->nlmsg_pid, nlh_src->nlmsg_seq,
150 			    nlh_src->nlmsg_type, payload, nlh_src->nlmsg_flags);
151 	if (!nlh_dst)
152 		return ERR_PTR(-EMSGSIZE);
153 
154 	memset(nlmsg_data(nlh_dst), 0, payload);
155 
156 	switch (nlh_src->nlmsg_type) {
157 	/* Compat message has the same layout as native */
158 	case XFRM_MSG_DELSA:
159 	case XFRM_MSG_DELPOLICY:
160 	case XFRM_MSG_FLUSHSA:
161 	case XFRM_MSG_FLUSHPOLICY:
162 	case XFRM_MSG_NEWAE:
163 	case XFRM_MSG_REPORT:
164 	case XFRM_MSG_MIGRATE:
165 	case XFRM_MSG_NEWSADINFO:
166 	case XFRM_MSG_NEWSPDINFO:
167 	case XFRM_MSG_MAPPING:
168 		WARN_ON_ONCE(src_len != payload);
169 		memcpy(nlmsg_data(nlh_dst), nlmsg_data(nlh_src), src_len);
170 		break;
171 	/* 4 byte alignment for trailing u64 on native, but not on compat */
172 	case XFRM_MSG_NEWSA:
173 	case XFRM_MSG_NEWPOLICY:
174 	case XFRM_MSG_UPDSA:
175 	case XFRM_MSG_UPDPOLICY:
176 		WARN_ON_ONCE(src_len != payload + 4);
177 		memcpy(nlmsg_data(nlh_dst), nlmsg_data(nlh_src), payload);
178 		break;
179 	case XFRM_MSG_EXPIRE: {
180 		const struct xfrm_user_expire *src_ue  = nlmsg_data(nlh_src);
181 		struct compat_xfrm_user_expire *dst_ue = nlmsg_data(nlh_dst);
182 
183 		/* compat_xfrm_user_expire has 4-byte smaller state */
184 		memcpy(dst_ue, src_ue, sizeof(dst_ue->state));
185 		dst_ue->hard = src_ue->hard;
186 		break;
187 	}
188 	case XFRM_MSG_ACQUIRE: {
189 		const struct xfrm_user_acquire *src_ua  = nlmsg_data(nlh_src);
190 		struct compat_xfrm_user_acquire *dst_ua = nlmsg_data(nlh_dst);
191 
192 		memcpy(dst_ua, src_ua, offsetof(struct compat_xfrm_user_acquire, aalgos));
193 		dst_ua->aalgos = src_ua->aalgos;
194 		dst_ua->ealgos = src_ua->ealgos;
195 		dst_ua->calgos = src_ua->calgos;
196 		dst_ua->seq    = src_ua->seq;
197 		break;
198 	}
199 	case XFRM_MSG_POLEXPIRE: {
200 		const struct xfrm_user_polexpire *src_upe  = nlmsg_data(nlh_src);
201 		struct compat_xfrm_user_polexpire *dst_upe = nlmsg_data(nlh_dst);
202 
203 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
204 		memcpy(dst_upe, src_upe, sizeof(dst_upe->pol));
205 		dst_upe->hard = src_upe->hard;
206 		break;
207 	}
208 	case XFRM_MSG_ALLOCSPI: {
209 		const struct xfrm_userspi_info *src_usi = nlmsg_data(nlh_src);
210 		struct compat_xfrm_userspi_info *dst_usi = nlmsg_data(nlh_dst);
211 
212 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
213 		memcpy(dst_usi, src_usi, sizeof(src_usi->info));
214 		dst_usi->min = src_usi->min;
215 		dst_usi->max = src_usi->max;
216 		break;
217 	}
218 	/* Not being sent by kernel */
219 	case XFRM_MSG_GETSA:
220 	case XFRM_MSG_GETPOLICY:
221 	case XFRM_MSG_GETAE:
222 	case XFRM_MSG_GETSADINFO:
223 	case XFRM_MSG_GETSPDINFO:
224 	default:
225 		pr_warn_once("unsupported nlmsg_type %d\n", nlh_src->nlmsg_type);
226 		return ERR_PTR(-EOPNOTSUPP);
227 	}
228 
229 	return nlh_dst;
230 }
231 
232 static int xfrm_nla_cpy(struct sk_buff *dst, const struct nlattr *src, int len)
233 {
234 	return nla_put(dst, src->nla_type, len, nla_data(src));
235 }
236 
237 static int xfrm_xlate64_attr(struct sk_buff *dst, const struct nlattr *src)
238 {
239 	switch (src->nla_type) {
240 	case XFRMA_PAD:
241 		/* Ignore */
242 		return 0;
243 	case XFRMA_UNSPEC:
244 	case XFRMA_ALG_AUTH:
245 	case XFRMA_ALG_CRYPT:
246 	case XFRMA_ALG_COMP:
247 	case XFRMA_ENCAP:
248 	case XFRMA_TMPL:
249 		return xfrm_nla_cpy(dst, src, nla_len(src));
250 	case XFRMA_SA:
251 		return xfrm_nla_cpy(dst, src, XMSGSIZE(compat_xfrm_usersa_info));
252 	case XFRMA_POLICY:
253 		return xfrm_nla_cpy(dst, src, XMSGSIZE(compat_xfrm_userpolicy_info));
254 	case XFRMA_SEC_CTX:
255 		return xfrm_nla_cpy(dst, src, nla_len(src));
256 	case XFRMA_LTIME_VAL:
257 		return nla_put_64bit(dst, src->nla_type, nla_len(src),
258 			nla_data(src), XFRMA_PAD);
259 	case XFRMA_REPLAY_VAL:
260 	case XFRMA_REPLAY_THRESH:
261 	case XFRMA_ETIMER_THRESH:
262 	case XFRMA_SRCADDR:
263 	case XFRMA_COADDR:
264 		return xfrm_nla_cpy(dst, src, nla_len(src));
265 	case XFRMA_LASTUSED:
266 		return nla_put_64bit(dst, src->nla_type, nla_len(src),
267 			nla_data(src), XFRMA_PAD);
268 	case XFRMA_POLICY_TYPE:
269 	case XFRMA_MIGRATE:
270 	case XFRMA_ALG_AEAD:
271 	case XFRMA_KMADDRESS:
272 	case XFRMA_ALG_AUTH_TRUNC:
273 	case XFRMA_MARK:
274 	case XFRMA_TFCPAD:
275 	case XFRMA_REPLAY_ESN_VAL:
276 	case XFRMA_SA_EXTRA_FLAGS:
277 	case XFRMA_PROTO:
278 	case XFRMA_ADDRESS_FILTER:
279 	case XFRMA_OFFLOAD_DEV:
280 	case XFRMA_SET_MARK:
281 	case XFRMA_SET_MARK_MASK:
282 	case XFRMA_IF_ID:
283 	case XFRMA_MTIMER_THRESH:
284 	case XFRMA_SA_DIR:
285 	case XFRMA_NAT_KEEPALIVE_INTERVAL:
286 	case XFRMA_SA_PCPU:
287 	case XFRMA_IPTFS_DROP_TIME:
288 	case XFRMA_IPTFS_REORDER_WINDOW:
289 	case XFRMA_IPTFS_DONT_FRAG:
290 	case XFRMA_IPTFS_INIT_DELAY:
291 	case XFRMA_IPTFS_MAX_QSIZE:
292 	case XFRMA_IPTFS_PKT_SIZE:
293 		return xfrm_nla_cpy(dst, src, nla_len(src));
294 	default:
295 		BUILD_BUG_ON(XFRMA_MAX != XFRMA_IPTFS_PKT_SIZE);
296 		pr_warn_once("unsupported nla_type %d\n", src->nla_type);
297 		return -EOPNOTSUPP;
298 	}
299 }
300 
301 /* Take kernel-built (64bit layout) and create 32bit layout for userspace */
302 static int xfrm_xlate64(struct sk_buff *dst, const struct nlmsghdr *nlh_src)
303 {
304 	u16 type = nlh_src->nlmsg_type - XFRM_MSG_BASE;
305 	const struct nlattr *nla, *attrs;
306 	struct nlmsghdr *nlh_dst;
307 	int len, remaining;
308 
309 	nlh_dst = xfrm_nlmsg_put_compat(dst, nlh_src, type);
310 	if (IS_ERR(nlh_dst))
311 		return PTR_ERR(nlh_dst);
312 
313 	attrs = nlmsg_attrdata(nlh_src, xfrm_msg_min[type]);
314 	len = nlmsg_attrlen(nlh_src, xfrm_msg_min[type]);
315 
316 	nla_for_each_attr(nla, attrs, len, remaining) {
317 		int err;
318 
319 		switch (nlh_src->nlmsg_type) {
320 		case XFRM_MSG_NEWSPDINFO:
321 			err = xfrm_nla_cpy(dst, nla, nla_len(nla));
322 			break;
323 		default:
324 			err = xfrm_xlate64_attr(dst, nla);
325 			break;
326 		}
327 		if (err)
328 			return err;
329 	}
330 
331 	nlmsg_end(dst, nlh_dst);
332 
333 	return 0;
334 }
335 
336 static int xfrm_alloc_compat(struct sk_buff *skb, const struct nlmsghdr *nlh_src)
337 {
338 	u16 type = nlh_src->nlmsg_type - XFRM_MSG_BASE;
339 	struct sk_buff *new = NULL;
340 	int err;
341 
342 	if (type >= ARRAY_SIZE(xfrm_msg_min)) {
343 		pr_warn_once("unsupported nlmsg_type %d\n", nlh_src->nlmsg_type);
344 		return -EOPNOTSUPP;
345 	}
346 
347 	if (skb_shinfo(skb)->frag_list == NULL) {
348 		new = alloc_skb(skb->len + skb_tailroom(skb), GFP_ATOMIC);
349 		if (!new)
350 			return -ENOMEM;
351 		skb_shinfo(skb)->frag_list = new;
352 	}
353 
354 	err = xfrm_xlate64(skb_shinfo(skb)->frag_list, nlh_src);
355 	if (err) {
356 		if (new) {
357 			kfree_skb(new);
358 			skb_shinfo(skb)->frag_list = NULL;
359 		}
360 		return err;
361 	}
362 
363 	return 0;
364 }
365 
366 /* Calculates len of translated 64-bit message. */
367 static size_t xfrm_user_rcv_calculate_len64(const struct nlmsghdr *src,
368 					    struct nlattr *attrs[XFRMA_MAX + 1],
369 					    int maxtype)
370 {
371 	size_t len = nlmsg_len(src);
372 
373 	switch (src->nlmsg_type) {
374 	case XFRM_MSG_NEWSA:
375 	case XFRM_MSG_NEWPOLICY:
376 	case XFRM_MSG_ALLOCSPI:
377 	case XFRM_MSG_ACQUIRE:
378 	case XFRM_MSG_UPDPOLICY:
379 	case XFRM_MSG_UPDSA:
380 		len += 4;
381 		break;
382 	case XFRM_MSG_EXPIRE:
383 	case XFRM_MSG_POLEXPIRE:
384 		len += 8;
385 		break;
386 	case XFRM_MSG_NEWSPDINFO:
387 		/* attirbutes are xfrm_spdattr_type_t, not xfrm_attr_type_t */
388 		return len;
389 	default:
390 		break;
391 	}
392 
393 	/* Unexpected for anything, but XFRM_MSG_NEWSPDINFO, please
394 	 * correct both 64=>32-bit and 32=>64-bit translators to copy
395 	 * new attributes.
396 	 */
397 	if (WARN_ON_ONCE(maxtype))
398 		return len;
399 
400 	if (attrs[XFRMA_SA])
401 		len += 4;
402 	if (attrs[XFRMA_POLICY])
403 		len += 4;
404 
405 	/* XXX: some attrs may need to be realigned
406 	 * if !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
407 	 */
408 
409 	return len;
410 }
411 
412 static int xfrm_attr_cpy32(void *dst, size_t *pos, const struct nlattr *src,
413 			   size_t size, int copy_len, int payload)
414 {
415 	struct nlmsghdr *nlmsg = dst;
416 	struct nlattr *nla;
417 
418 	/* xfrm_user_rcv_msg_compat() relies on fact that 32-bit messages
419 	 * have the same len or shorted than 64-bit ones.
420 	 * 32-bit translation that is bigger than 64-bit original is unexpected.
421 	 */
422 	if (WARN_ON_ONCE(copy_len > payload))
423 		copy_len = payload;
424 
425 	if (size - *pos < nla_attr_size(payload))
426 		return -ENOBUFS;
427 
428 	nla = dst + *pos;
429 
430 	memcpy(nla, src, nla_attr_size(copy_len));
431 	nla->nla_len = nla_attr_size(payload);
432 	*pos += nla_attr_size(copy_len);
433 	nlmsg->nlmsg_len += nla->nla_len;
434 
435 	memset(dst + *pos, 0, payload - copy_len);
436 	*pos += payload - copy_len;
437 
438 	return 0;
439 }
440 
441 static int xfrm_xlate32_attr(void *dst, const struct nlattr *nla,
442 			     size_t *pos, size_t size,
443 			     struct netlink_ext_ack *extack)
444 {
445 	int type = nla_type(nla);
446 	u16 pol_len32, pol_len64;
447 	int err;
448 
449 	if (type > XFRMA_MAX) {
450 		BUILD_BUG_ON(XFRMA_MAX != XFRMA_IPTFS_PKT_SIZE);
451 		NL_SET_ERR_MSG(extack, "Bad attribute");
452 		return -EOPNOTSUPP;
453 	}
454 	type = array_index_nospec(type, XFRMA_MAX + 1);
455 	if (nla_len(nla) < compat_policy[type].len) {
456 		NL_SET_ERR_MSG(extack, "Attribute bad length");
457 		return -EOPNOTSUPP;
458 	}
459 
460 	pol_len32 = compat_policy[type].len;
461 	pol_len64 = xfrma_policy[type].len;
462 
463 	/* XFRMA_SA and XFRMA_POLICY - need to know how-to translate */
464 	if (pol_len32 != pol_len64) {
465 		if (nla_len(nla) != compat_policy[type].len) {
466 			NL_SET_ERR_MSG(extack, "Attribute bad length");
467 			return -EOPNOTSUPP;
468 		}
469 		err = xfrm_attr_cpy32(dst, pos, nla, size, pol_len32, pol_len64);
470 		if (err)
471 			return err;
472 	}
473 
474 	return xfrm_attr_cpy32(dst, pos, nla, size, nla_len(nla), nla_len(nla));
475 }
476 
477 static int xfrm_xlate32(struct nlmsghdr *dst, const struct nlmsghdr *src,
478 			struct nlattr *attrs[XFRMA_MAX+1],
479 			size_t size, u8 type, int maxtype,
480 			struct netlink_ext_ack *extack)
481 {
482 	size_t pos;
483 	int i;
484 
485 	memcpy(dst, src, NLMSG_HDRLEN);
486 	dst->nlmsg_len = NLMSG_HDRLEN + xfrm_msg_min[type];
487 	memset(nlmsg_data(dst), 0, xfrm_msg_min[type]);
488 
489 	switch (src->nlmsg_type) {
490 	/* Compat message has the same layout as native */
491 	case XFRM_MSG_DELSA:
492 	case XFRM_MSG_GETSA:
493 	case XFRM_MSG_DELPOLICY:
494 	case XFRM_MSG_GETPOLICY:
495 	case XFRM_MSG_FLUSHSA:
496 	case XFRM_MSG_FLUSHPOLICY:
497 	case XFRM_MSG_NEWAE:
498 	case XFRM_MSG_GETAE:
499 	case XFRM_MSG_REPORT:
500 	case XFRM_MSG_MIGRATE:
501 	case XFRM_MSG_NEWSADINFO:
502 	case XFRM_MSG_GETSADINFO:
503 	case XFRM_MSG_NEWSPDINFO:
504 	case XFRM_MSG_GETSPDINFO:
505 	case XFRM_MSG_MAPPING:
506 		memcpy(nlmsg_data(dst), nlmsg_data(src), compat_msg_min[type]);
507 		break;
508 	/* 4 byte alignment for trailing u64 on native, but not on compat */
509 	case XFRM_MSG_NEWSA:
510 	case XFRM_MSG_NEWPOLICY:
511 	case XFRM_MSG_UPDSA:
512 	case XFRM_MSG_UPDPOLICY:
513 		memcpy(nlmsg_data(dst), nlmsg_data(src), compat_msg_min[type]);
514 		break;
515 	case XFRM_MSG_EXPIRE: {
516 		const struct compat_xfrm_user_expire *src_ue = nlmsg_data(src);
517 		struct xfrm_user_expire *dst_ue = nlmsg_data(dst);
518 
519 		/* compat_xfrm_user_expire has 4-byte smaller state */
520 		memcpy(dst_ue, src_ue, sizeof(src_ue->state));
521 		dst_ue->hard = src_ue->hard;
522 		break;
523 	}
524 	case XFRM_MSG_ACQUIRE: {
525 		const struct compat_xfrm_user_acquire *src_ua = nlmsg_data(src);
526 		struct xfrm_user_acquire *dst_ua = nlmsg_data(dst);
527 
528 		memcpy(dst_ua, src_ua, offsetof(struct compat_xfrm_user_acquire, aalgos));
529 		dst_ua->aalgos = src_ua->aalgos;
530 		dst_ua->ealgos = src_ua->ealgos;
531 		dst_ua->calgos = src_ua->calgos;
532 		dst_ua->seq    = src_ua->seq;
533 		break;
534 	}
535 	case XFRM_MSG_POLEXPIRE: {
536 		const struct compat_xfrm_user_polexpire *src_upe = nlmsg_data(src);
537 		struct xfrm_user_polexpire *dst_upe = nlmsg_data(dst);
538 
539 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
540 		memcpy(dst_upe, src_upe, sizeof(src_upe->pol));
541 		dst_upe->hard = src_upe->hard;
542 		break;
543 	}
544 	case XFRM_MSG_ALLOCSPI: {
545 		const struct compat_xfrm_userspi_info *src_usi = nlmsg_data(src);
546 		struct xfrm_userspi_info *dst_usi = nlmsg_data(dst);
547 
548 		/* compat_xfrm_user_polexpire has 4-byte smaller state */
549 		memcpy(dst_usi, src_usi, sizeof(src_usi->info));
550 		dst_usi->min = src_usi->min;
551 		dst_usi->max = src_usi->max;
552 		break;
553 	}
554 	default:
555 		NL_SET_ERR_MSG(extack, "Unsupported message type");
556 		return -EOPNOTSUPP;
557 	}
558 	pos = dst->nlmsg_len;
559 
560 	if (maxtype) {
561 		/* attirbutes are xfrm_spdattr_type_t, not xfrm_attr_type_t */
562 		WARN_ON_ONCE(src->nlmsg_type != XFRM_MSG_NEWSPDINFO);
563 
564 		for (i = 1; i <= maxtype; i++) {
565 			int err;
566 
567 			if (!attrs[i])
568 				continue;
569 
570 			/* just copy - no need for translation */
571 			err = xfrm_attr_cpy32(dst, &pos, attrs[i], size,
572 					nla_len(attrs[i]), nla_len(attrs[i]));
573 			if (err)
574 				return err;
575 		}
576 		return 0;
577 	}
578 
579 	for (i = 1; i < XFRMA_MAX + 1; i++) {
580 		int err;
581 
582 		if (i == XFRMA_PAD)
583 			continue;
584 
585 		if (!attrs[i])
586 			continue;
587 
588 		err = xfrm_xlate32_attr(dst, attrs[i], &pos, size, extack);
589 		if (err)
590 			return err;
591 	}
592 
593 	return 0;
594 }
595 
596 static struct nlmsghdr *xfrm_user_rcv_msg_compat(const struct nlmsghdr *h32,
597 			int maxtype, const struct nla_policy *policy,
598 			struct netlink_ext_ack *extack)
599 {
600 	/* netlink_rcv_skb() checks if a message has full (struct nlmsghdr) */
601 	u16 type = h32->nlmsg_type - XFRM_MSG_BASE;
602 	struct nlattr *attrs[XFRMA_MAX+1];
603 	struct nlmsghdr *h64;
604 	size_t len;
605 	int err;
606 
607 	BUILD_BUG_ON(ARRAY_SIZE(xfrm_msg_min) != ARRAY_SIZE(compat_msg_min));
608 
609 	if (type >= ARRAY_SIZE(xfrm_msg_min))
610 		return ERR_PTR(-EINVAL);
611 
612 	/* Don't call parse: the message might have only nlmsg header */
613 	if ((h32->nlmsg_type == XFRM_MSG_GETSA ||
614 	     h32->nlmsg_type == XFRM_MSG_GETPOLICY) &&
615 	    (h32->nlmsg_flags & NLM_F_DUMP))
616 		return NULL;
617 
618 	err = nlmsg_parse_deprecated(h32, compat_msg_min[type], attrs,
619 			maxtype ? : XFRMA_MAX, policy ? : compat_policy, extack);
620 	if (err < 0)
621 		return ERR_PTR(err);
622 
623 	len = xfrm_user_rcv_calculate_len64(h32, attrs, maxtype);
624 	/* The message doesn't need translation */
625 	if (len == nlmsg_len(h32))
626 		return NULL;
627 
628 	len += NLMSG_HDRLEN;
629 	h64 = kvmalloc(len, GFP_KERNEL);
630 	if (!h64)
631 		return ERR_PTR(-ENOMEM);
632 
633 	err = xfrm_xlate32(h64, h32, attrs, len, type, maxtype, extack);
634 	if (err < 0) {
635 		kvfree(h64);
636 		return ERR_PTR(err);
637 	}
638 
639 	return h64;
640 }
641 
642 static int xfrm_user_policy_compat(u8 **pdata32, int optlen)
643 {
644 	struct compat_xfrm_userpolicy_info *p = (void *)*pdata32;
645 	u8 *src_templates, *dst_templates;
646 	u8 *data64;
647 
648 	if (optlen < sizeof(*p))
649 		return -EINVAL;
650 
651 	data64 = kmalloc_track_caller(optlen + 4, GFP_USER | __GFP_NOWARN);
652 	if (!data64)
653 		return -ENOMEM;
654 
655 	memcpy(data64, *pdata32, sizeof(*p));
656 	memset(data64 + sizeof(*p), 0, 4);
657 
658 	src_templates = *pdata32 + sizeof(*p);
659 	dst_templates = data64 + sizeof(*p) + 4;
660 	memcpy(dst_templates, src_templates, optlen - sizeof(*p));
661 
662 	kfree(*pdata32);
663 	*pdata32 = data64;
664 	return 0;
665 }
666 
667 static struct xfrm_translator xfrm_translator = {
668 	.owner				= THIS_MODULE,
669 	.alloc_compat			= xfrm_alloc_compat,
670 	.rcv_msg_compat			= xfrm_user_rcv_msg_compat,
671 	.xlate_user_policy_sockptr	= xfrm_user_policy_compat,
672 };
673 
674 static int __init xfrm_compat_init(void)
675 {
676 	return xfrm_register_translator(&xfrm_translator);
677 }
678 
679 static void __exit xfrm_compat_exit(void)
680 {
681 	xfrm_unregister_translator(&xfrm_translator);
682 }
683 
684 module_init(xfrm_compat_init);
685 module_exit(xfrm_compat_exit);
686 MODULE_LICENSE("GPL");
687 MODULE_AUTHOR("Dmitry Safonov");
688 MODULE_DESCRIPTION("XFRM 32-bit compatibility layer");
689