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