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1#define pr_fmt(fmt) "IPsec: " fmt
2
3#include <crypto/hash.h>
4#include <linux/err.h>
5#include <linux/module.h>
6#include <linux/slab.h>
7#include <net/ip.h>
8#include <net/xfrm.h>
9#include <net/ah.h>
10#include <linux/crypto.h>
11#include <linux/pfkeyv2.h>
12#include <linux/scatterlist.h>
13#include <net/icmp.h>
14#include <net/protocol.h>
15
16struct ah_skb_cb {
17 struct xfrm_skb_cb xfrm;
18 void *tmp;
19};
20
21#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
22
23static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
24 unsigned int size)
25{
26 unsigned int len;
27
28 len = size + crypto_ahash_digestsize(ahash) +
29 (crypto_ahash_alignmask(ahash) &
30 ~(crypto_tfm_ctx_alignment() - 1));
31
32 len = ALIGN(len, crypto_tfm_ctx_alignment());
33
34 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
35 len = ALIGN(len, __alignof__(struct scatterlist));
36
37 len += sizeof(struct scatterlist) * nfrags;
38
39 return kmalloc(len, GFP_ATOMIC);
40}
41
42static inline u8 *ah_tmp_auth(void *tmp, unsigned int offset)
43{
44 return tmp + offset;
45}
46
47static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
48 unsigned int offset)
49{
50 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
51}
52
53static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
54 u8 *icv)
55{
56 struct ahash_request *req;
57
58 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
59 crypto_tfm_ctx_alignment());
60
61 ahash_request_set_tfm(req, ahash);
62
63 return req;
64}
65
66static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
67 struct ahash_request *req)
68{
69 return (void *)ALIGN((unsigned long)(req + 1) +
70 crypto_ahash_reqsize(ahash),
71 __alignof__(struct scatterlist));
72}
73
74/* Clear mutable options and find final destination to substitute
75 * into IP header for icv calculation. Options are already checked
76 * for validity, so paranoia is not required. */
77
78static int ip_clear_mutable_options(const struct iphdr *iph, __be32 *daddr)
79{
80 unsigned char *optptr = (unsigned char *)(iph+1);
81 int l = iph->ihl*4 - sizeof(struct iphdr);
82 int optlen;
83
84 while (l > 0) {
85 switch (*optptr) {
86 case IPOPT_END:
87 return 0;
88 case IPOPT_NOOP:
89 l--;
90 optptr++;
91 continue;
92 }
93 optlen = optptr[1];
94 if (optlen<2 || optlen>l)
95 return -EINVAL;
96 switch (*optptr) {
97 case IPOPT_SEC:
98 case 0x85: /* Some "Extended Security" crap. */
99 case IPOPT_CIPSO:
100 case IPOPT_RA:
101 case 0x80|21: /* RFC1770 */
102 break;
103 case IPOPT_LSRR:
104 case IPOPT_SSRR:
105 if (optlen < 6)
106 return -EINVAL;
107 memcpy(daddr, optptr+optlen-4, 4);
108 /* Fall through */
109 default:
110 memset(optptr, 0, optlen);
111 }
112 l -= optlen;
113 optptr += optlen;
114 }
115 return 0;
116}
117
118static void ah_output_done(struct crypto_async_request *base, int err)
119{
120 u8 *icv;
121 struct iphdr *iph;
122 struct sk_buff *skb = base->data;
123 struct xfrm_state *x = skb_dst(skb)->xfrm;
124 struct ah_data *ahp = x->data;
125 struct iphdr *top_iph = ip_hdr(skb);
126 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
127 int ihl = ip_hdrlen(skb);
128
129 iph = AH_SKB_CB(skb)->tmp;
130 icv = ah_tmp_icv(ahp->ahash, iph, ihl);
131 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
132
133 top_iph->tos = iph->tos;
134 top_iph->ttl = iph->ttl;
135 top_iph->frag_off = iph->frag_off;
136 if (top_iph->ihl != 5) {
137 top_iph->daddr = iph->daddr;
138 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
139 }
140
141 kfree(AH_SKB_CB(skb)->tmp);
142 xfrm_output_resume(skb, err);
143}
144
145static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
146{
147 int err;
148 int nfrags;
149 int ihl;
150 u8 *icv;
151 struct sk_buff *trailer;
152 struct crypto_ahash *ahash;
153 struct ahash_request *req;
154 struct scatterlist *sg;
155 struct iphdr *iph, *top_iph;
156 struct ip_auth_hdr *ah;
157 struct ah_data *ahp;
158
159 ahp = x->data;
160 ahash = ahp->ahash;
161
162 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
163 goto out;
164 nfrags = err;
165
166 skb_push(skb, -skb_network_offset(skb));
167 ah = ip_auth_hdr(skb);
168 ihl = ip_hdrlen(skb);
169
170 err = -ENOMEM;
171 iph = ah_alloc_tmp(ahash, nfrags, ihl);
172 if (!iph)
173 goto out;
174
175 icv = ah_tmp_icv(ahash, iph, ihl);
176 req = ah_tmp_req(ahash, icv);
177 sg = ah_req_sg(ahash, req);
178
179 memset(ah->auth_data, 0, ahp->icv_trunc_len);
180
181 top_iph = ip_hdr(skb);
182
183 iph->tos = top_iph->tos;
184 iph->ttl = top_iph->ttl;
185 iph->frag_off = top_iph->frag_off;
186
187 if (top_iph->ihl != 5) {
188 iph->daddr = top_iph->daddr;
189 memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
190 err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
191 if (err)
192 goto out_free;
193 }
194
195 ah->nexthdr = *skb_mac_header(skb);
196 *skb_mac_header(skb) = IPPROTO_AH;
197
198 top_iph->tos = 0;
199 top_iph->tot_len = htons(skb->len);
200 top_iph->frag_off = 0;
201 top_iph->ttl = 0;
202 top_iph->check = 0;
203
204 if (x->props.flags & XFRM_STATE_ALIGN4)
205 ah->hdrlen = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
206 else
207 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
208
209 ah->reserved = 0;
210 ah->spi = x->id.spi;
211 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
212
213 sg_init_table(sg, nfrags);
214 skb_to_sgvec(skb, sg, 0, skb->len);
215
216 ahash_request_set_crypt(req, sg, icv, skb->len);
217 ahash_request_set_callback(req, 0, ah_output_done, skb);
218
219 AH_SKB_CB(skb)->tmp = iph;
220
221 err = crypto_ahash_digest(req);
222 if (err) {
223 if (err == -EINPROGRESS)
224 goto out;
225
226 if (err == -EBUSY)
227 err = NET_XMIT_DROP;
228 goto out_free;
229 }
230
231 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
232
233 top_iph->tos = iph->tos;
234 top_iph->ttl = iph->ttl;
235 top_iph->frag_off = iph->frag_off;
236 if (top_iph->ihl != 5) {
237 top_iph->daddr = iph->daddr;
238 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
239 }
240
241out_free:
242 kfree(iph);
243out:
244 return err;
245}
246
247static void ah_input_done(struct crypto_async_request *base, int err)
248{
249 u8 *auth_data;
250 u8 *icv;
251 struct iphdr *work_iph;
252 struct sk_buff *skb = base->data;
253 struct xfrm_state *x = xfrm_input_state(skb);
254 struct ah_data *ahp = x->data;
255 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
256 int ihl = ip_hdrlen(skb);
257 int ah_hlen = (ah->hdrlen + 2) << 2;
258
259 work_iph = AH_SKB_CB(skb)->tmp;
260 auth_data = ah_tmp_auth(work_iph, ihl);
261 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
262
263 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
264 if (err)
265 goto out;
266
267 err = ah->nexthdr;
268
269 skb->network_header += ah_hlen;
270 memcpy(skb_network_header(skb), work_iph, ihl);
271 __skb_pull(skb, ah_hlen + ihl);
272 skb_set_transport_header(skb, -ihl);
273out:
274 kfree(AH_SKB_CB(skb)->tmp);
275 xfrm_input_resume(skb, err);
276}
277
278static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
279{
280 int ah_hlen;
281 int ihl;
282 int nexthdr;
283 int nfrags;
284 u8 *auth_data;
285 u8 *icv;
286 struct sk_buff *trailer;
287 struct crypto_ahash *ahash;
288 struct ahash_request *req;
289 struct scatterlist *sg;
290 struct iphdr *iph, *work_iph;
291 struct ip_auth_hdr *ah;
292 struct ah_data *ahp;
293 int err = -ENOMEM;
294
295 if (!pskb_may_pull(skb, sizeof(*ah)))
296 goto out;
297
298 ah = (struct ip_auth_hdr *)skb->data;
299 ahp = x->data;
300 ahash = ahp->ahash;
301
302 nexthdr = ah->nexthdr;
303 ah_hlen = (ah->hdrlen + 2) << 2;
304
305 if (x->props.flags & XFRM_STATE_ALIGN4) {
306 if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
307 ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
308 goto out;
309 } else {
310 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
311 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
312 goto out;
313 }
314
315 if (!pskb_may_pull(skb, ah_hlen))
316 goto out;
317
318 /* We are going to _remove_ AH header to keep sockets happy,
319 * so... Later this can change. */
320 if (skb_cloned(skb) &&
321 pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
322 goto out;
323
324 skb->ip_summed = CHECKSUM_NONE;
325
326
327 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
328 goto out;
329 nfrags = err;
330
331 ah = (struct ip_auth_hdr *)skb->data;
332 iph = ip_hdr(skb);
333 ihl = ip_hdrlen(skb);
334
335 work_iph = ah_alloc_tmp(ahash, nfrags, ihl + ahp->icv_trunc_len);
336 if (!work_iph)
337 goto out;
338
339 auth_data = ah_tmp_auth(work_iph, ihl);
340 icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
341 req = ah_tmp_req(ahash, icv);
342 sg = ah_req_sg(ahash, req);
343
344 memcpy(work_iph, iph, ihl);
345 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
346 memset(ah->auth_data, 0, ahp->icv_trunc_len);
347
348 iph->ttl = 0;
349 iph->tos = 0;
350 iph->frag_off = 0;
351 iph->check = 0;
352 if (ihl > sizeof(*iph)) {
353 __be32 dummy;
354 err = ip_clear_mutable_options(iph, &dummy);
355 if (err)
356 goto out_free;
357 }
358
359 skb_push(skb, ihl);
360
361 sg_init_table(sg, nfrags);
362 skb_to_sgvec(skb, sg, 0, skb->len);
363
364 ahash_request_set_crypt(req, sg, icv, skb->len);
365 ahash_request_set_callback(req, 0, ah_input_done, skb);
366
367 AH_SKB_CB(skb)->tmp = work_iph;
368
369 err = crypto_ahash_digest(req);
370 if (err) {
371 if (err == -EINPROGRESS)
372 goto out;
373
374 goto out_free;
375 }
376
377 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
378 if (err)
379 goto out_free;
380
381 skb->network_header += ah_hlen;
382 memcpy(skb_network_header(skb), work_iph, ihl);
383 __skb_pull(skb, ah_hlen + ihl);
384 skb_set_transport_header(skb, -ihl);
385
386 err = nexthdr;
387
388out_free:
389 kfree (work_iph);
390out:
391 return err;
392}
393
394static void ah4_err(struct sk_buff *skb, u32 info)
395{
396 struct net *net = dev_net(skb->dev);
397 const struct iphdr *iph = (const struct iphdr *)skb->data;
398 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
399 struct xfrm_state *x;
400
401 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
402 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
403 return;
404
405 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
406 ah->spi, IPPROTO_AH, AF_INET);
407 if (!x)
408 return;
409 pr_debug("pmtu discovery on SA AH/%08x/%08x\n",
410 ntohl(ah->spi), ntohl(iph->daddr));
411 xfrm_state_put(x);
412}
413
414static int ah_init_state(struct xfrm_state *x)
415{
416 struct ah_data *ahp = NULL;
417 struct xfrm_algo_desc *aalg_desc;
418 struct crypto_ahash *ahash;
419
420 if (!x->aalg)
421 goto error;
422
423 if (x->encap)
424 goto error;
425
426 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
427 if (!ahp)
428 return -ENOMEM;
429
430 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
431 if (IS_ERR(ahash))
432 goto error;
433
434 ahp->ahash = ahash;
435 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
436 (x->aalg->alg_key_len + 7) / 8))
437 goto error;
438
439 /*
440 * Lookup the algorithm description maintained by xfrm_algo,
441 * verify crypto transform properties, and store information
442 * we need for AH processing. This lookup cannot fail here
443 * after a successful crypto_alloc_ahash().
444 */
445 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
446 BUG_ON(!aalg_desc);
447
448 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
449 crypto_ahash_digestsize(ahash)) {
450 pr_info("%s: %s digestsize %u != %hu\n",
451 __func__, x->aalg->alg_name,
452 crypto_ahash_digestsize(ahash),
453 aalg_desc->uinfo.auth.icv_fullbits / 8);
454 goto error;
455 }
456
457 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
458 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
459
460 BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
461
462 if (x->props.flags & XFRM_STATE_ALIGN4)
463 x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
464 ahp->icv_trunc_len);
465 else
466 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
467 ahp->icv_trunc_len);
468 if (x->props.mode == XFRM_MODE_TUNNEL)
469 x->props.header_len += sizeof(struct iphdr);
470 x->data = ahp;
471
472 return 0;
473
474error:
475 if (ahp) {
476 crypto_free_ahash(ahp->ahash);
477 kfree(ahp);
478 }
479 return -EINVAL;
480}
481
482static void ah_destroy(struct xfrm_state *x)
483{
484 struct ah_data *ahp = x->data;
485
486 if (!ahp)
487 return;
488
489 crypto_free_ahash(ahp->ahash);
490 kfree(ahp);
491}
492
493
494static const struct xfrm_type ah_type =
495{
496 .description = "AH4",
497 .owner = THIS_MODULE,
498 .proto = IPPROTO_AH,
499 .flags = XFRM_TYPE_REPLAY_PROT,
500 .init_state = ah_init_state,
501 .destructor = ah_destroy,
502 .input = ah_input,
503 .output = ah_output
504};
505
506static const struct net_protocol ah4_protocol = {
507 .handler = xfrm4_rcv,
508 .err_handler = ah4_err,
509 .no_policy = 1,
510 .netns_ok = 1,
511};
512
513static int __init ah4_init(void)
514{
515 if (xfrm_register_type(&ah_type, AF_INET) < 0) {
516 pr_info("%s: can't add xfrm type\n", __func__);
517 return -EAGAIN;
518 }
519 if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
520 pr_info("%s: can't add protocol\n", __func__);
521 xfrm_unregister_type(&ah_type, AF_INET);
522 return -EAGAIN;
523 }
524 return 0;
525}
526
527static void __exit ah4_fini(void)
528{
529 if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
530 pr_info("%s: can't remove protocol\n", __func__);
531 if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
532 pr_info("%s: can't remove xfrm type\n", __func__);
533}
534
535module_init(ah4_init);
536module_exit(ah4_fini);
537MODULE_LICENSE("GPL");
538MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);
1// SPDX-License-Identifier: GPL-2.0-only
2#define pr_fmt(fmt) "IPsec: " fmt
3
4#include <crypto/algapi.h>
5#include <crypto/hash.h>
6#include <linux/err.h>
7#include <linux/module.h>
8#include <linux/slab.h>
9#include <net/ip.h>
10#include <net/xfrm.h>
11#include <net/ah.h>
12#include <linux/crypto.h>
13#include <linux/pfkeyv2.h>
14#include <linux/scatterlist.h>
15#include <net/icmp.h>
16#include <net/protocol.h>
17
18struct ah_skb_cb {
19 struct xfrm_skb_cb xfrm;
20 void *tmp;
21};
22
23#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
24
25static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
26 unsigned int size)
27{
28 unsigned int len;
29
30 len = size + crypto_ahash_digestsize(ahash) +
31 (crypto_ahash_alignmask(ahash) &
32 ~(crypto_tfm_ctx_alignment() - 1));
33
34 len = ALIGN(len, crypto_tfm_ctx_alignment());
35
36 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
37 len = ALIGN(len, __alignof__(struct scatterlist));
38
39 len += sizeof(struct scatterlist) * nfrags;
40
41 return kmalloc(len, GFP_ATOMIC);
42}
43
44static inline u8 *ah_tmp_auth(void *tmp, unsigned int offset)
45{
46 return tmp + offset;
47}
48
49static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
50 unsigned int offset)
51{
52 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
53}
54
55static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
56 u8 *icv)
57{
58 struct ahash_request *req;
59
60 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
61 crypto_tfm_ctx_alignment());
62
63 ahash_request_set_tfm(req, ahash);
64
65 return req;
66}
67
68static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
69 struct ahash_request *req)
70{
71 return (void *)ALIGN((unsigned long)(req + 1) +
72 crypto_ahash_reqsize(ahash),
73 __alignof__(struct scatterlist));
74}
75
76/* Clear mutable options and find final destination to substitute
77 * into IP header for icv calculation. Options are already checked
78 * for validity, so paranoia is not required. */
79
80static int ip_clear_mutable_options(const struct iphdr *iph, __be32 *daddr)
81{
82 unsigned char *optptr = (unsigned char *)(iph+1);
83 int l = iph->ihl*4 - sizeof(struct iphdr);
84 int optlen;
85
86 while (l > 0) {
87 switch (*optptr) {
88 case IPOPT_END:
89 return 0;
90 case IPOPT_NOOP:
91 l--;
92 optptr++;
93 continue;
94 }
95 optlen = optptr[1];
96 if (optlen<2 || optlen>l)
97 return -EINVAL;
98 switch (*optptr) {
99 case IPOPT_SEC:
100 case 0x85: /* Some "Extended Security" crap. */
101 case IPOPT_CIPSO:
102 case IPOPT_RA:
103 case 0x80|21: /* RFC1770 */
104 break;
105 case IPOPT_LSRR:
106 case IPOPT_SSRR:
107 if (optlen < 6)
108 return -EINVAL;
109 memcpy(daddr, optptr+optlen-4, 4);
110 fallthrough;
111 default:
112 memset(optptr, 0, optlen);
113 }
114 l -= optlen;
115 optptr += optlen;
116 }
117 return 0;
118}
119
120static void ah_output_done(struct crypto_async_request *base, int err)
121{
122 u8 *icv;
123 struct iphdr *iph;
124 struct sk_buff *skb = base->data;
125 struct xfrm_state *x = skb_dst(skb)->xfrm;
126 struct ah_data *ahp = x->data;
127 struct iphdr *top_iph = ip_hdr(skb);
128 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
129 int ihl = ip_hdrlen(skb);
130
131 iph = AH_SKB_CB(skb)->tmp;
132 icv = ah_tmp_icv(ahp->ahash, iph, ihl);
133 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
134
135 top_iph->tos = iph->tos;
136 top_iph->ttl = iph->ttl;
137 top_iph->frag_off = iph->frag_off;
138 if (top_iph->ihl != 5) {
139 top_iph->daddr = iph->daddr;
140 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
141 }
142
143 kfree(AH_SKB_CB(skb)->tmp);
144 xfrm_output_resume(skb->sk, skb, err);
145}
146
147static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
148{
149 int err;
150 int nfrags;
151 int ihl;
152 u8 *icv;
153 struct sk_buff *trailer;
154 struct crypto_ahash *ahash;
155 struct ahash_request *req;
156 struct scatterlist *sg;
157 struct iphdr *iph, *top_iph;
158 struct ip_auth_hdr *ah;
159 struct ah_data *ahp;
160 int seqhi_len = 0;
161 __be32 *seqhi;
162 int sglists = 0;
163 struct scatterlist *seqhisg;
164
165 ahp = x->data;
166 ahash = ahp->ahash;
167
168 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
169 goto out;
170 nfrags = err;
171
172 skb_push(skb, -skb_network_offset(skb));
173 ah = ip_auth_hdr(skb);
174 ihl = ip_hdrlen(skb);
175
176 if (x->props.flags & XFRM_STATE_ESN) {
177 sglists = 1;
178 seqhi_len = sizeof(*seqhi);
179 }
180 err = -ENOMEM;
181 iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl + seqhi_len);
182 if (!iph)
183 goto out;
184 seqhi = (__be32 *)((char *)iph + ihl);
185 icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
186 req = ah_tmp_req(ahash, icv);
187 sg = ah_req_sg(ahash, req);
188 seqhisg = sg + nfrags;
189
190 memset(ah->auth_data, 0, ahp->icv_trunc_len);
191
192 top_iph = ip_hdr(skb);
193
194 iph->tos = top_iph->tos;
195 iph->ttl = top_iph->ttl;
196 iph->frag_off = top_iph->frag_off;
197
198 if (top_iph->ihl != 5) {
199 iph->daddr = top_iph->daddr;
200 memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
201 err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
202 if (err)
203 goto out_free;
204 }
205
206 ah->nexthdr = *skb_mac_header(skb);
207 *skb_mac_header(skb) = IPPROTO_AH;
208
209 top_iph->tos = 0;
210 top_iph->tot_len = htons(skb->len);
211 top_iph->frag_off = 0;
212 top_iph->ttl = 0;
213 top_iph->check = 0;
214
215 if (x->props.flags & XFRM_STATE_ALIGN4)
216 ah->hdrlen = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
217 else
218 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
219
220 ah->reserved = 0;
221 ah->spi = x->id.spi;
222 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
223
224 sg_init_table(sg, nfrags + sglists);
225 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
226 if (unlikely(err < 0))
227 goto out_free;
228
229 if (x->props.flags & XFRM_STATE_ESN) {
230 /* Attach seqhi sg right after packet payload */
231 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
232 sg_set_buf(seqhisg, seqhi, seqhi_len);
233 }
234 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
235 ahash_request_set_callback(req, 0, ah_output_done, skb);
236
237 AH_SKB_CB(skb)->tmp = iph;
238
239 err = crypto_ahash_digest(req);
240 if (err) {
241 if (err == -EINPROGRESS)
242 goto out;
243
244 if (err == -ENOSPC)
245 err = NET_XMIT_DROP;
246 goto out_free;
247 }
248
249 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
250
251 top_iph->tos = iph->tos;
252 top_iph->ttl = iph->ttl;
253 top_iph->frag_off = iph->frag_off;
254 if (top_iph->ihl != 5) {
255 top_iph->daddr = iph->daddr;
256 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
257 }
258
259out_free:
260 kfree(iph);
261out:
262 return err;
263}
264
265static void ah_input_done(struct crypto_async_request *base, int err)
266{
267 u8 *auth_data;
268 u8 *icv;
269 struct iphdr *work_iph;
270 struct sk_buff *skb = base->data;
271 struct xfrm_state *x = xfrm_input_state(skb);
272 struct ah_data *ahp = x->data;
273 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
274 int ihl = ip_hdrlen(skb);
275 int ah_hlen = (ah->hdrlen + 2) << 2;
276
277 if (err)
278 goto out;
279
280 work_iph = AH_SKB_CB(skb)->tmp;
281 auth_data = ah_tmp_auth(work_iph, ihl);
282 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
283
284 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
285 if (err)
286 goto out;
287
288 err = ah->nexthdr;
289
290 skb->network_header += ah_hlen;
291 memcpy(skb_network_header(skb), work_iph, ihl);
292 __skb_pull(skb, ah_hlen + ihl);
293
294 if (x->props.mode == XFRM_MODE_TUNNEL)
295 skb_reset_transport_header(skb);
296 else
297 skb_set_transport_header(skb, -ihl);
298out:
299 kfree(AH_SKB_CB(skb)->tmp);
300 xfrm_input_resume(skb, err);
301}
302
303static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
304{
305 int ah_hlen;
306 int ihl;
307 int nexthdr;
308 int nfrags;
309 u8 *auth_data;
310 u8 *icv;
311 struct sk_buff *trailer;
312 struct crypto_ahash *ahash;
313 struct ahash_request *req;
314 struct scatterlist *sg;
315 struct iphdr *iph, *work_iph;
316 struct ip_auth_hdr *ah;
317 struct ah_data *ahp;
318 int err = -ENOMEM;
319 int seqhi_len = 0;
320 __be32 *seqhi;
321 int sglists = 0;
322 struct scatterlist *seqhisg;
323
324 if (!pskb_may_pull(skb, sizeof(*ah)))
325 goto out;
326
327 ah = (struct ip_auth_hdr *)skb->data;
328 ahp = x->data;
329 ahash = ahp->ahash;
330
331 nexthdr = ah->nexthdr;
332 ah_hlen = (ah->hdrlen + 2) << 2;
333
334 if (x->props.flags & XFRM_STATE_ALIGN4) {
335 if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
336 ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
337 goto out;
338 } else {
339 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
340 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
341 goto out;
342 }
343
344 if (!pskb_may_pull(skb, ah_hlen))
345 goto out;
346
347 /* We are going to _remove_ AH header to keep sockets happy,
348 * so... Later this can change. */
349 if (skb_unclone(skb, GFP_ATOMIC))
350 goto out;
351
352 skb->ip_summed = CHECKSUM_NONE;
353
354
355 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
356 goto out;
357 nfrags = err;
358
359 ah = (struct ip_auth_hdr *)skb->data;
360 iph = ip_hdr(skb);
361 ihl = ip_hdrlen(skb);
362
363 if (x->props.flags & XFRM_STATE_ESN) {
364 sglists = 1;
365 seqhi_len = sizeof(*seqhi);
366 }
367
368 work_iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl +
369 ahp->icv_trunc_len + seqhi_len);
370 if (!work_iph) {
371 err = -ENOMEM;
372 goto out;
373 }
374
375 seqhi = (__be32 *)((char *)work_iph + ihl);
376 auth_data = ah_tmp_auth(seqhi, seqhi_len);
377 icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
378 req = ah_tmp_req(ahash, icv);
379 sg = ah_req_sg(ahash, req);
380 seqhisg = sg + nfrags;
381
382 memcpy(work_iph, iph, ihl);
383 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
384 memset(ah->auth_data, 0, ahp->icv_trunc_len);
385
386 iph->ttl = 0;
387 iph->tos = 0;
388 iph->frag_off = 0;
389 iph->check = 0;
390 if (ihl > sizeof(*iph)) {
391 __be32 dummy;
392 err = ip_clear_mutable_options(iph, &dummy);
393 if (err)
394 goto out_free;
395 }
396
397 skb_push(skb, ihl);
398
399 sg_init_table(sg, nfrags + sglists);
400 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
401 if (unlikely(err < 0))
402 goto out_free;
403
404 if (x->props.flags & XFRM_STATE_ESN) {
405 /* Attach seqhi sg right after packet payload */
406 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
407 sg_set_buf(seqhisg, seqhi, seqhi_len);
408 }
409 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
410 ahash_request_set_callback(req, 0, ah_input_done, skb);
411
412 AH_SKB_CB(skb)->tmp = work_iph;
413
414 err = crypto_ahash_digest(req);
415 if (err) {
416 if (err == -EINPROGRESS)
417 goto out;
418
419 goto out_free;
420 }
421
422 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
423 if (err)
424 goto out_free;
425
426 skb->network_header += ah_hlen;
427 memcpy(skb_network_header(skb), work_iph, ihl);
428 __skb_pull(skb, ah_hlen + ihl);
429 if (x->props.mode == XFRM_MODE_TUNNEL)
430 skb_reset_transport_header(skb);
431 else
432 skb_set_transport_header(skb, -ihl);
433
434 err = nexthdr;
435
436out_free:
437 kfree (work_iph);
438out:
439 return err;
440}
441
442static int ah4_err(struct sk_buff *skb, u32 info)
443{
444 struct net *net = dev_net(skb->dev);
445 const struct iphdr *iph = (const struct iphdr *)skb->data;
446 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
447 struct xfrm_state *x;
448
449 switch (icmp_hdr(skb)->type) {
450 case ICMP_DEST_UNREACH:
451 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
452 return 0;
453 break;
454 case ICMP_REDIRECT:
455 break;
456 default:
457 return 0;
458 }
459
460 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
461 ah->spi, IPPROTO_AH, AF_INET);
462 if (!x)
463 return 0;
464
465 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
466 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_AH);
467 else
468 ipv4_redirect(skb, net, 0, IPPROTO_AH);
469 xfrm_state_put(x);
470
471 return 0;
472}
473
474static int ah_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
475{
476 struct ah_data *ahp = NULL;
477 struct xfrm_algo_desc *aalg_desc;
478 struct crypto_ahash *ahash;
479
480 if (!x->aalg) {
481 NL_SET_ERR_MSG(extack, "AH requires a state with an AUTH algorithm");
482 goto error;
483 }
484
485 if (x->encap) {
486 NL_SET_ERR_MSG(extack, "AH is not compatible with encapsulation");
487 goto error;
488 }
489
490 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
491 if (!ahp)
492 return -ENOMEM;
493
494 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
495 if (IS_ERR(ahash)) {
496 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
497 goto error;
498 }
499
500 ahp->ahash = ahash;
501 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
502 (x->aalg->alg_key_len + 7) / 8)) {
503 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
504 goto error;
505 }
506
507 /*
508 * Lookup the algorithm description maintained by xfrm_algo,
509 * verify crypto transform properties, and store information
510 * we need for AH processing. This lookup cannot fail here
511 * after a successful crypto_alloc_ahash().
512 */
513 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
514 BUG_ON(!aalg_desc);
515
516 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
517 crypto_ahash_digestsize(ahash)) {
518 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
519 goto error;
520 }
521
522 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
523 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
524
525 if (x->props.flags & XFRM_STATE_ALIGN4)
526 x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
527 ahp->icv_trunc_len);
528 else
529 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
530 ahp->icv_trunc_len);
531 if (x->props.mode == XFRM_MODE_TUNNEL)
532 x->props.header_len += sizeof(struct iphdr);
533 x->data = ahp;
534
535 return 0;
536
537error:
538 if (ahp) {
539 crypto_free_ahash(ahp->ahash);
540 kfree(ahp);
541 }
542 return -EINVAL;
543}
544
545static void ah_destroy(struct xfrm_state *x)
546{
547 struct ah_data *ahp = x->data;
548
549 if (!ahp)
550 return;
551
552 crypto_free_ahash(ahp->ahash);
553 kfree(ahp);
554}
555
556static int ah4_rcv_cb(struct sk_buff *skb, int err)
557{
558 return 0;
559}
560
561static const struct xfrm_type ah_type =
562{
563 .owner = THIS_MODULE,
564 .proto = IPPROTO_AH,
565 .flags = XFRM_TYPE_REPLAY_PROT,
566 .init_state = ah_init_state,
567 .destructor = ah_destroy,
568 .input = ah_input,
569 .output = ah_output
570};
571
572static struct xfrm4_protocol ah4_protocol = {
573 .handler = xfrm4_rcv,
574 .input_handler = xfrm_input,
575 .cb_handler = ah4_rcv_cb,
576 .err_handler = ah4_err,
577 .priority = 0,
578};
579
580static int __init ah4_init(void)
581{
582 if (xfrm_register_type(&ah_type, AF_INET) < 0) {
583 pr_info("%s: can't add xfrm type\n", __func__);
584 return -EAGAIN;
585 }
586 if (xfrm4_protocol_register(&ah4_protocol, IPPROTO_AH) < 0) {
587 pr_info("%s: can't add protocol\n", __func__);
588 xfrm_unregister_type(&ah_type, AF_INET);
589 return -EAGAIN;
590 }
591 return 0;
592}
593
594static void __exit ah4_fini(void)
595{
596 if (xfrm4_protocol_deregister(&ah4_protocol, IPPROTO_AH) < 0)
597 pr_info("%s: can't remove protocol\n", __func__);
598 xfrm_unregister_type(&ah_type, AF_INET);
599}
600
601module_init(ah4_init);
602module_exit(ah4_fini);
603MODULE_LICENSE("GPL");
604MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);