2 #include <linux/module.h>
6 #include <asm/scatterlist.h>
7 #include <linux/crypto.h>
8 #include <linux/kernel.h>
9 #include <linux/pfkeyv2.h>
10 #include <linux/random.h>
12 #include <net/protocol.h>
15 static int esp_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
18 struct iphdr
*top_iph
;
19 struct ip_esp_hdr
*esph
;
20 struct crypto_blkcipher
*tfm
;
21 struct blkcipher_desc desc
;
23 struct sk_buff
*trailer
;
30 /* Strip IP+ESP header. */
31 __skb_pull(skb
, skb_transport_offset(skb
));
32 /* Now skb is pure payload to encrypt */
36 /* Round to block size */
40 alen
= esp
->auth
.icv_trunc_len
;
44 blksize
= ALIGN(crypto_blkcipher_blocksize(tfm
), 4);
45 clen
= ALIGN(clen
+ 2, blksize
);
47 clen
= ALIGN(clen
, esp
->conf
.padlen
);
49 if ((nfrags
= skb_cow_data(skb
, clen
-skb
->len
+alen
, &trailer
)) < 0)
53 tail
= skb_tail_pointer(trailer
);
56 for (i
=0; i
<clen
-skb
->len
- 2; i
++)
59 tail
[clen
- skb
->len
- 2] = (clen
- skb
->len
) - 2;
60 pskb_put(skb
, trailer
, clen
- skb
->len
);
62 __skb_push(skb
, skb
->data
- skb_network_header(skb
));
63 top_iph
= ip_hdr(skb
);
64 esph
= (struct ip_esp_hdr
*)(skb_network_header(skb
) +
66 top_iph
->tot_len
= htons(skb
->len
+ alen
);
67 *(skb_tail_pointer(trailer
) - 1) = top_iph
->protocol
;
69 /* this is non-NULL only with UDP Encapsulation */
71 struct xfrm_encap_tmpl
*encap
= x
->encap
;
75 uh
= (struct udphdr
*)esph
;
76 uh
->source
= encap
->encap_sport
;
77 uh
->dest
= encap
->encap_dport
;
78 uh
->len
= htons(skb
->len
+ alen
- top_iph
->ihl
*4);
81 switch (encap
->encap_type
) {
83 case UDP_ENCAP_ESPINUDP
:
84 esph
= (struct ip_esp_hdr
*)(uh
+ 1);
86 case UDP_ENCAP_ESPINUDP_NON_IKE
:
87 udpdata32
= (__be32
*)(uh
+ 1);
88 udpdata32
[0] = udpdata32
[1] = 0;
89 esph
= (struct ip_esp_hdr
*)(udpdata32
+ 2);
93 top_iph
->protocol
= IPPROTO_UDP
;
95 top_iph
->protocol
= IPPROTO_ESP
;
97 esph
->spi
= x
->id
.spi
;
98 esph
->seq_no
= htonl(++x
->replay
.oseq
);
99 xfrm_aevent_doreplay(x
);
101 if (esp
->conf
.ivlen
) {
102 if (unlikely(!esp
->conf
.ivinitted
)) {
103 get_random_bytes(esp
->conf
.ivec
, esp
->conf
.ivlen
);
104 esp
->conf
.ivinitted
= 1;
106 crypto_blkcipher_set_iv(tfm
, esp
->conf
.ivec
, esp
->conf
.ivlen
);
110 struct scatterlist
*sg
= &esp
->sgbuf
[0];
112 if (unlikely(nfrags
> ESP_NUM_FAST_SG
)) {
113 sg
= kmalloc(sizeof(struct scatterlist
)*nfrags
, GFP_ATOMIC
);
117 skb_to_sgvec(skb
, sg
, esph
->enc_data
+esp
->conf
.ivlen
-skb
->data
, clen
);
118 err
= crypto_blkcipher_encrypt(&desc
, sg
, sg
, clen
);
119 if (unlikely(sg
!= &esp
->sgbuf
[0]))
126 if (esp
->conf
.ivlen
) {
127 memcpy(esph
->enc_data
, esp
->conf
.ivec
, esp
->conf
.ivlen
);
128 crypto_blkcipher_get_iv(tfm
, esp
->conf
.ivec
, esp
->conf
.ivlen
);
131 if (esp
->auth
.icv_full_len
) {
132 err
= esp_mac_digest(esp
, skb
, (u8
*)esph
- skb
->data
,
133 sizeof(*esph
) + esp
->conf
.ivlen
+ clen
);
134 memcpy(pskb_put(skb
, trailer
, alen
), esp
->auth
.work_icv
, alen
);
137 ip_send_check(top_iph
);
144 * Note: detecting truncated vs. non-truncated authentication data is very
145 * expensive, so we only support truncated data, which is the recommended
148 static int esp_input(struct xfrm_state
*x
, struct sk_buff
*skb
)
151 struct ip_esp_hdr
*esph
;
152 struct esp_data
*esp
= x
->data
;
153 struct crypto_blkcipher
*tfm
= esp
->conf
.tfm
;
154 struct blkcipher_desc desc
= { .tfm
= tfm
};
155 struct sk_buff
*trailer
;
156 int blksize
= ALIGN(crypto_blkcipher_blocksize(tfm
), 4);
157 int alen
= esp
->auth
.icv_trunc_len
;
158 int elen
= skb
->len
- sizeof(struct ip_esp_hdr
) - esp
->conf
.ivlen
- alen
;
162 struct scatterlist
*sg
;
166 if (!pskb_may_pull(skb
, sizeof(struct ip_esp_hdr
)))
169 if (elen
<= 0 || (elen
& (blksize
-1)))
172 /* If integrity check is required, do this. */
173 if (esp
->auth
.icv_full_len
) {
176 err
= esp_mac_digest(esp
, skb
, 0, skb
->len
- alen
);
180 if (skb_copy_bits(skb
, skb
->len
- alen
, sum
, alen
))
183 if (unlikely(memcmp(esp
->auth
.work_icv
, sum
, alen
))) {
184 x
->stats
.integrity_failed
++;
189 if ((nfrags
= skb_cow_data(skb
, 0, &trailer
)) < 0)
192 skb
->ip_summed
= CHECKSUM_NONE
;
194 esph
= (struct ip_esp_hdr
*)skb
->data
;
196 /* Get ivec. This can be wrong, check against another impls. */
198 crypto_blkcipher_set_iv(tfm
, esph
->enc_data
, esp
->conf
.ivlen
);
202 if (unlikely(nfrags
> ESP_NUM_FAST_SG
)) {
203 sg
= kmalloc(sizeof(struct scatterlist
)*nfrags
, GFP_ATOMIC
);
207 skb_to_sgvec(skb
, sg
, sizeof(struct ip_esp_hdr
) + esp
->conf
.ivlen
, elen
);
208 err
= crypto_blkcipher_decrypt(&desc
, sg
, sg
, elen
);
209 if (unlikely(sg
!= &esp
->sgbuf
[0]))
214 if (skb_copy_bits(skb
, skb
->len
-alen
-2, nexthdr
, 2))
218 if (padlen
+2 >= elen
)
221 /* ... check padding bits here. Silly. :-) */
227 struct xfrm_encap_tmpl
*encap
= x
->encap
;
228 struct udphdr
*uh
= (void *)(skb_network_header(skb
) + ihl
);
231 * 1) if the NAT-T peer's IP or port changed then
232 * advertize the change to the keying daemon.
233 * This is an inbound SA, so just compare
236 if (iph
->saddr
!= x
->props
.saddr
.a4
||
237 uh
->source
!= encap
->encap_sport
) {
238 xfrm_address_t ipaddr
;
240 ipaddr
.a4
= iph
->saddr
;
241 km_new_mapping(x
, &ipaddr
, uh
->source
);
243 /* XXX: perhaps add an extra
244 * policy check here, to see
245 * if we should allow or
246 * reject a packet from a
253 * 2) ignore UDP/TCP checksums in case
254 * of NAT-T in Transport Mode, or
255 * perform other post-processing fixes
256 * as per draft-ietf-ipsec-udp-encaps-06,
259 if (x
->props
.mode
== XFRM_MODE_TRANSPORT
||
260 x
->props
.mode
== XFRM_MODE_BEET
)
261 skb
->ip_summed
= CHECKSUM_UNNECESSARY
;
264 iph
->protocol
= nexthdr
[1];
265 pskb_trim(skb
, skb
->len
- alen
- padlen
- 2);
266 __skb_pull(skb
, sizeof(*esph
) + esp
->conf
.ivlen
);
267 skb_set_transport_header(skb
, -ihl
);
275 static u32
esp4_get_mtu(struct xfrm_state
*x
, int mtu
)
277 struct esp_data
*esp
= x
->data
;
278 u32 blksize
= ALIGN(crypto_blkcipher_blocksize(esp
->conf
.tfm
), 4);
279 u32 align
= max_t(u32
, blksize
, esp
->conf
.padlen
);
282 mtu
-= x
->props
.header_len
+ esp
->auth
.icv_trunc_len
;
283 rem
= mtu
& (align
- 1);
286 switch (x
->props
.mode
) {
287 case XFRM_MODE_TUNNEL
:
290 case XFRM_MODE_TRANSPORT
:
293 mtu
+= min_t(u32
, blksize
- 4, rem
);
296 /* The worst case. */
297 mtu
+= min_t(u32
, IPV4_BEET_PHMAXLEN
, rem
);
304 static void esp4_err(struct sk_buff
*skb
, u32 info
)
306 struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
307 struct ip_esp_hdr
*esph
= (struct ip_esp_hdr
*)(skb
->data
+(iph
->ihl
<<2));
308 struct xfrm_state
*x
;
310 if (icmp_hdr(skb
)->type
!= ICMP_DEST_UNREACH
||
311 icmp_hdr(skb
)->code
!= ICMP_FRAG_NEEDED
)
314 x
= xfrm_state_lookup((xfrm_address_t
*)&iph
->daddr
, esph
->spi
, IPPROTO_ESP
, AF_INET
);
317 NETDEBUG(KERN_DEBUG
"pmtu discovery on SA ESP/%08x/%08x\n",
318 ntohl(esph
->spi
), ntohl(iph
->daddr
));
322 static void esp_destroy(struct xfrm_state
*x
)
324 struct esp_data
*esp
= x
->data
;
329 crypto_free_blkcipher(esp
->conf
.tfm
);
330 esp
->conf
.tfm
= NULL
;
331 kfree(esp
->conf
.ivec
);
332 esp
->conf
.ivec
= NULL
;
333 crypto_free_hash(esp
->auth
.tfm
);
334 esp
->auth
.tfm
= NULL
;
335 kfree(esp
->auth
.work_icv
);
336 esp
->auth
.work_icv
= NULL
;
340 static int esp_init_state(struct xfrm_state
*x
)
342 struct esp_data
*esp
= NULL
;
343 struct crypto_blkcipher
*tfm
;
346 /* null auth and encryption can have zero length keys */
348 if (x
->aalg
->alg_key_len
> 512)
354 esp
= kzalloc(sizeof(*esp
), GFP_KERNEL
);
359 struct xfrm_algo_desc
*aalg_desc
;
360 struct crypto_hash
*hash
;
362 esp
->auth
.key
= x
->aalg
->alg_key
;
363 esp
->auth
.key_len
= (x
->aalg
->alg_key_len
+7)/8;
364 hash
= crypto_alloc_hash(x
->aalg
->alg_name
, 0,
369 esp
->auth
.tfm
= hash
;
370 if (crypto_hash_setkey(hash
, esp
->auth
.key
, esp
->auth
.key_len
))
373 aalg_desc
= xfrm_aalg_get_byname(x
->aalg
->alg_name
, 0);
376 if (aalg_desc
->uinfo
.auth
.icv_fullbits
/8 !=
377 crypto_hash_digestsize(hash
)) {
378 NETDEBUG(KERN_INFO
"ESP: %s digestsize %u != %hu\n",
380 crypto_hash_digestsize(hash
),
381 aalg_desc
->uinfo
.auth
.icv_fullbits
/8);
385 esp
->auth
.icv_full_len
= aalg_desc
->uinfo
.auth
.icv_fullbits
/8;
386 esp
->auth
.icv_trunc_len
= aalg_desc
->uinfo
.auth
.icv_truncbits
/8;
388 esp
->auth
.work_icv
= kmalloc(esp
->auth
.icv_full_len
, GFP_KERNEL
);
389 if (!esp
->auth
.work_icv
)
392 esp
->conf
.key
= x
->ealg
->alg_key
;
393 esp
->conf
.key_len
= (x
->ealg
->alg_key_len
+7)/8;
394 tfm
= crypto_alloc_blkcipher(x
->ealg
->alg_name
, 0, CRYPTO_ALG_ASYNC
);
398 esp
->conf
.ivlen
= crypto_blkcipher_ivsize(tfm
);
399 esp
->conf
.padlen
= 0;
400 if (esp
->conf
.ivlen
) {
401 esp
->conf
.ivec
= kmalloc(esp
->conf
.ivlen
, GFP_KERNEL
);
402 if (unlikely(esp
->conf
.ivec
== NULL
))
404 esp
->conf
.ivinitted
= 0;
406 if (crypto_blkcipher_setkey(tfm
, esp
->conf
.key
, esp
->conf
.key_len
))
408 x
->props
.header_len
= sizeof(struct ip_esp_hdr
) + esp
->conf
.ivlen
;
409 if (x
->props
.mode
== XFRM_MODE_TUNNEL
)
410 x
->props
.header_len
+= sizeof(struct iphdr
);
411 else if (x
->props
.mode
== XFRM_MODE_BEET
)
412 x
->props
.header_len
+= IPV4_BEET_PHMAXLEN
;
414 struct xfrm_encap_tmpl
*encap
= x
->encap
;
416 switch (encap
->encap_type
) {
419 case UDP_ENCAP_ESPINUDP
:
420 x
->props
.header_len
+= sizeof(struct udphdr
);
422 case UDP_ENCAP_ESPINUDP_NON_IKE
:
423 x
->props
.header_len
+= sizeof(struct udphdr
) + 2 * sizeof(u32
);
428 align
= ALIGN(crypto_blkcipher_blocksize(esp
->conf
.tfm
), 4);
429 if (esp
->conf
.padlen
)
430 align
= max_t(u32
, align
, esp
->conf
.padlen
);
431 x
->props
.trailer_len
= align
+ 1 + esp
->auth
.icv_trunc_len
;
441 static struct xfrm_type esp_type
=
443 .description
= "ESP4",
444 .owner
= THIS_MODULE
,
445 .proto
= IPPROTO_ESP
,
446 .init_state
= esp_init_state
,
447 .destructor
= esp_destroy
,
448 .get_mtu
= esp4_get_mtu
,
453 static struct net_protocol esp4_protocol
= {
454 .handler
= xfrm4_rcv
,
455 .err_handler
= esp4_err
,
459 static int __init
esp4_init(void)
461 if (xfrm_register_type(&esp_type
, AF_INET
) < 0) {
462 printk(KERN_INFO
"ip esp init: can't add xfrm type\n");
465 if (inet_add_protocol(&esp4_protocol
, IPPROTO_ESP
) < 0) {
466 printk(KERN_INFO
"ip esp init: can't add protocol\n");
467 xfrm_unregister_type(&esp_type
, AF_INET
);
473 static void __exit
esp4_fini(void)
475 if (inet_del_protocol(&esp4_protocol
, IPPROTO_ESP
) < 0)
476 printk(KERN_INFO
"ip esp close: can't remove protocol\n");
477 if (xfrm_unregister_type(&esp_type
, AF_INET
) < 0)
478 printk(KERN_INFO
"ip esp close: can't remove xfrm type\n");
481 module_init(esp4_init
);
482 module_exit(esp4_fini
);
483 MODULE_LICENSE("GPL");
484 MODULE_ALIAS_XFRM_TYPE(AF_INET
, XFRM_PROTO_ESP
);