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>
11 #include <linux/spinlock.h>
13 #include <net/protocol.h>
16 static int esp_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
19 struct ip_esp_hdr
*esph
;
20 struct crypto_blkcipher
*tfm
;
21 struct blkcipher_desc desc
;
23 struct sk_buff
*trailer
;
30 /* skb is pure payload to encrypt */
34 /* Round to block size */
38 alen
= esp
->auth
.icv_trunc_len
;
42 blksize
= ALIGN(crypto_blkcipher_blocksize(tfm
), 4);
43 clen
= ALIGN(clen
+ 2, blksize
);
45 clen
= ALIGN(clen
, esp
->conf
.padlen
);
47 if ((nfrags
= skb_cow_data(skb
, clen
-skb
->len
+alen
, &trailer
)) < 0)
51 tail
= skb_tail_pointer(trailer
);
54 for (i
=0; i
<clen
-skb
->len
- 2; i
++)
57 tail
[clen
- skb
->len
- 2] = (clen
- skb
->len
) - 2;
58 pskb_put(skb
, trailer
, clen
- skb
->len
);
60 skb_push(skb
, -skb_network_offset(skb
));
61 esph
= ip_esp_hdr(skb
);
62 *(skb_tail_pointer(trailer
) - 1) = *skb_mac_header(skb
);
63 *skb_mac_header(skb
) = IPPROTO_ESP
;
65 spin_lock_bh(&x
->lock
);
67 /* this is non-NULL only with UDP Encapsulation */
69 struct xfrm_encap_tmpl
*encap
= x
->encap
;
73 uh
= (struct udphdr
*)esph
;
74 uh
->source
= encap
->encap_sport
;
75 uh
->dest
= encap
->encap_dport
;
76 uh
->len
= htons(skb
->len
+ alen
- skb_transport_offset(skb
));
79 switch (encap
->encap_type
) {
81 case UDP_ENCAP_ESPINUDP
:
82 esph
= (struct ip_esp_hdr
*)(uh
+ 1);
84 case UDP_ENCAP_ESPINUDP_NON_IKE
:
85 udpdata32
= (__be32
*)(uh
+ 1);
86 udpdata32
[0] = udpdata32
[1] = 0;
87 esph
= (struct ip_esp_hdr
*)(udpdata32
+ 2);
91 *skb_mac_header(skb
) = IPPROTO_UDP
;
94 esph
->spi
= x
->id
.spi
;
95 esph
->seq_no
= htonl(XFRM_SKB_CB(skb
)->seq
);
97 if (esp
->conf
.ivlen
) {
98 if (unlikely(!esp
->conf
.ivinitted
)) {
99 get_random_bytes(esp
->conf
.ivec
, esp
->conf
.ivlen
);
100 esp
->conf
.ivinitted
= 1;
102 crypto_blkcipher_set_iv(tfm
, esp
->conf
.ivec
, esp
->conf
.ivlen
);
106 struct scatterlist
*sg
= &esp
->sgbuf
[0];
108 if (unlikely(nfrags
> ESP_NUM_FAST_SG
)) {
109 sg
= kmalloc(sizeof(struct scatterlist
)*nfrags
, GFP_ATOMIC
);
113 skb_to_sgvec(skb
, sg
, esph
->enc_data
+esp
->conf
.ivlen
-skb
->data
, clen
);
114 err
= crypto_blkcipher_encrypt(&desc
, sg
, sg
, clen
);
115 if (unlikely(sg
!= &esp
->sgbuf
[0]))
122 if (esp
->conf
.ivlen
) {
123 memcpy(esph
->enc_data
, esp
->conf
.ivec
, esp
->conf
.ivlen
);
124 crypto_blkcipher_get_iv(tfm
, esp
->conf
.ivec
, esp
->conf
.ivlen
);
127 if (esp
->auth
.icv_full_len
) {
128 err
= esp_mac_digest(esp
, skb
, (u8
*)esph
- skb
->data
,
129 sizeof(*esph
) + esp
->conf
.ivlen
+ clen
);
130 memcpy(pskb_put(skb
, trailer
, alen
), esp
->auth
.work_icv
, alen
);
134 spin_unlock_bh(&x
->lock
);
141 * Note: detecting truncated vs. non-truncated authentication data is very
142 * expensive, so we only support truncated data, which is the recommended
145 static int esp_input(struct xfrm_state
*x
, struct sk_buff
*skb
)
148 struct ip_esp_hdr
*esph
;
149 struct esp_data
*esp
= x
->data
;
150 struct crypto_blkcipher
*tfm
= esp
->conf
.tfm
;
151 struct blkcipher_desc desc
= { .tfm
= tfm
};
152 struct sk_buff
*trailer
;
153 int blksize
= ALIGN(crypto_blkcipher_blocksize(tfm
), 4);
154 int alen
= esp
->auth
.icv_trunc_len
;
155 int elen
= skb
->len
- sizeof(*esph
) - esp
->conf
.ivlen
- alen
;
159 struct scatterlist
*sg
;
163 if (!pskb_may_pull(skb
, sizeof(*esph
)))
166 if (elen
<= 0 || (elen
& (blksize
-1)))
169 /* If integrity check is required, do this. */
170 if (esp
->auth
.icv_full_len
) {
173 err
= esp_mac_digest(esp
, skb
, 0, skb
->len
- alen
);
177 if (skb_copy_bits(skb
, skb
->len
- alen
, sum
, alen
))
180 if (unlikely(memcmp(esp
->auth
.work_icv
, sum
, alen
))) {
181 x
->stats
.integrity_failed
++;
186 if ((nfrags
= skb_cow_data(skb
, 0, &trailer
)) < 0)
189 skb
->ip_summed
= CHECKSUM_NONE
;
191 esph
= (struct ip_esp_hdr
*)skb
->data
;
193 /* Get ivec. This can be wrong, check against another impls. */
195 crypto_blkcipher_set_iv(tfm
, esph
->enc_data
, esp
->conf
.ivlen
);
199 if (unlikely(nfrags
> ESP_NUM_FAST_SG
)) {
200 sg
= kmalloc(sizeof(struct scatterlist
)*nfrags
, GFP_ATOMIC
);
204 skb_to_sgvec(skb
, sg
, sizeof(*esph
) + esp
->conf
.ivlen
, elen
);
205 err
= crypto_blkcipher_decrypt(&desc
, sg
, sg
, elen
);
206 if (unlikely(sg
!= &esp
->sgbuf
[0]))
211 if (skb_copy_bits(skb
, skb
->len
-alen
-2, nexthdr
, 2))
215 if (padlen
+2 >= elen
)
218 /* ... check padding bits here. Silly. :-) */
224 struct xfrm_encap_tmpl
*encap
= x
->encap
;
225 struct udphdr
*uh
= (void *)(skb_network_header(skb
) + ihl
);
228 * 1) if the NAT-T peer's IP or port changed then
229 * advertize the change to the keying daemon.
230 * This is an inbound SA, so just compare
233 if (iph
->saddr
!= x
->props
.saddr
.a4
||
234 uh
->source
!= encap
->encap_sport
) {
235 xfrm_address_t ipaddr
;
237 ipaddr
.a4
= iph
->saddr
;
238 km_new_mapping(x
, &ipaddr
, uh
->source
);
240 /* XXX: perhaps add an extra
241 * policy check here, to see
242 * if we should allow or
243 * reject a packet from a
250 * 2) ignore UDP/TCP checksums in case
251 * of NAT-T in Transport Mode, or
252 * perform other post-processing fixes
253 * as per draft-ietf-ipsec-udp-encaps-06,
256 if (x
->props
.mode
== XFRM_MODE_TRANSPORT
)
257 skb
->ip_summed
= CHECKSUM_UNNECESSARY
;
260 pskb_trim(skb
, skb
->len
- alen
- padlen
- 2);
261 __skb_pull(skb
, sizeof(*esph
) + esp
->conf
.ivlen
);
262 skb_set_transport_header(skb
, -ihl
);
270 static u32
esp4_get_mtu(struct xfrm_state
*x
, int mtu
)
272 struct esp_data
*esp
= x
->data
;
273 u32 blksize
= ALIGN(crypto_blkcipher_blocksize(esp
->conf
.tfm
), 4);
274 u32 align
= max_t(u32
, blksize
, esp
->conf
.padlen
);
277 mtu
-= x
->props
.header_len
+ esp
->auth
.icv_trunc_len
;
278 rem
= mtu
& (align
- 1);
281 switch (x
->props
.mode
) {
282 case XFRM_MODE_TUNNEL
:
285 case XFRM_MODE_TRANSPORT
:
288 mtu
+= min_t(u32
, blksize
- 4, rem
);
291 /* The worst case. */
292 mtu
+= min_t(u32
, IPV4_BEET_PHMAXLEN
, rem
);
299 static void esp4_err(struct sk_buff
*skb
, u32 info
)
301 struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
302 struct ip_esp_hdr
*esph
= (struct ip_esp_hdr
*)(skb
->data
+(iph
->ihl
<<2));
303 struct xfrm_state
*x
;
305 if (icmp_hdr(skb
)->type
!= ICMP_DEST_UNREACH
||
306 icmp_hdr(skb
)->code
!= ICMP_FRAG_NEEDED
)
309 x
= xfrm_state_lookup((xfrm_address_t
*)&iph
->daddr
, esph
->spi
, IPPROTO_ESP
, AF_INET
);
312 NETDEBUG(KERN_DEBUG
"pmtu discovery on SA ESP/%08x/%08x\n",
313 ntohl(esph
->spi
), ntohl(iph
->daddr
));
317 static void esp_destroy(struct xfrm_state
*x
)
319 struct esp_data
*esp
= x
->data
;
324 crypto_free_blkcipher(esp
->conf
.tfm
);
325 esp
->conf
.tfm
= NULL
;
326 kfree(esp
->conf
.ivec
);
327 esp
->conf
.ivec
= NULL
;
328 crypto_free_hash(esp
->auth
.tfm
);
329 esp
->auth
.tfm
= NULL
;
330 kfree(esp
->auth
.work_icv
);
331 esp
->auth
.work_icv
= NULL
;
335 static int esp_init_state(struct xfrm_state
*x
)
337 struct esp_data
*esp
= NULL
;
338 struct crypto_blkcipher
*tfm
;
344 esp
= kzalloc(sizeof(*esp
), GFP_KERNEL
);
349 struct xfrm_algo_desc
*aalg_desc
;
350 struct crypto_hash
*hash
;
352 hash
= crypto_alloc_hash(x
->aalg
->alg_name
, 0,
357 esp
->auth
.tfm
= hash
;
358 if (crypto_hash_setkey(hash
, x
->aalg
->alg_key
,
359 (x
->aalg
->alg_key_len
+ 7) / 8))
362 aalg_desc
= xfrm_aalg_get_byname(x
->aalg
->alg_name
, 0);
365 if (aalg_desc
->uinfo
.auth
.icv_fullbits
/8 !=
366 crypto_hash_digestsize(hash
)) {
367 NETDEBUG(KERN_INFO
"ESP: %s digestsize %u != %hu\n",
369 crypto_hash_digestsize(hash
),
370 aalg_desc
->uinfo
.auth
.icv_fullbits
/8);
374 esp
->auth
.icv_full_len
= aalg_desc
->uinfo
.auth
.icv_fullbits
/8;
375 esp
->auth
.icv_trunc_len
= aalg_desc
->uinfo
.auth
.icv_truncbits
/8;
377 esp
->auth
.work_icv
= kmalloc(esp
->auth
.icv_full_len
, GFP_KERNEL
);
378 if (!esp
->auth
.work_icv
)
382 tfm
= crypto_alloc_blkcipher(x
->ealg
->alg_name
, 0, CRYPTO_ALG_ASYNC
);
386 esp
->conf
.ivlen
= crypto_blkcipher_ivsize(tfm
);
387 esp
->conf
.padlen
= 0;
388 if (esp
->conf
.ivlen
) {
389 esp
->conf
.ivec
= kmalloc(esp
->conf
.ivlen
, GFP_KERNEL
);
390 if (unlikely(esp
->conf
.ivec
== NULL
))
392 esp
->conf
.ivinitted
= 0;
394 if (crypto_blkcipher_setkey(tfm
, x
->ealg
->alg_key
,
395 (x
->ealg
->alg_key_len
+ 7) / 8))
397 x
->props
.header_len
= sizeof(struct ip_esp_hdr
) + esp
->conf
.ivlen
;
398 if (x
->props
.mode
== XFRM_MODE_TUNNEL
)
399 x
->props
.header_len
+= sizeof(struct iphdr
);
400 else if (x
->props
.mode
== XFRM_MODE_BEET
)
401 x
->props
.header_len
+= IPV4_BEET_PHMAXLEN
;
403 struct xfrm_encap_tmpl
*encap
= x
->encap
;
405 switch (encap
->encap_type
) {
408 case UDP_ENCAP_ESPINUDP
:
409 x
->props
.header_len
+= sizeof(struct udphdr
);
411 case UDP_ENCAP_ESPINUDP_NON_IKE
:
412 x
->props
.header_len
+= sizeof(struct udphdr
) + 2 * sizeof(u32
);
417 align
= ALIGN(crypto_blkcipher_blocksize(esp
->conf
.tfm
), 4);
418 if (esp
->conf
.padlen
)
419 align
= max_t(u32
, align
, esp
->conf
.padlen
);
420 x
->props
.trailer_len
= align
+ 1 + esp
->auth
.icv_trunc_len
;
430 static struct xfrm_type esp_type
=
432 .description
= "ESP4",
433 .owner
= THIS_MODULE
,
434 .proto
= IPPROTO_ESP
,
435 .flags
= XFRM_TYPE_REPLAY_PROT
,
436 .init_state
= esp_init_state
,
437 .destructor
= esp_destroy
,
438 .get_mtu
= esp4_get_mtu
,
443 static struct net_protocol esp4_protocol
= {
444 .handler
= xfrm4_rcv
,
445 .err_handler
= esp4_err
,
449 static int __init
esp4_init(void)
451 if (xfrm_register_type(&esp_type
, AF_INET
) < 0) {
452 printk(KERN_INFO
"ip esp init: can't add xfrm type\n");
455 if (inet_add_protocol(&esp4_protocol
, IPPROTO_ESP
) < 0) {
456 printk(KERN_INFO
"ip esp init: can't add protocol\n");
457 xfrm_unregister_type(&esp_type
, AF_INET
);
463 static void __exit
esp4_fini(void)
465 if (inet_del_protocol(&esp4_protocol
, IPPROTO_ESP
) < 0)
466 printk(KERN_INFO
"ip esp close: can't remove protocol\n");
467 if (xfrm_unregister_type(&esp_type
, AF_INET
) < 0)
468 printk(KERN_INFO
"ip esp close: can't remove xfrm type\n");
471 module_init(esp4_init
);
472 module_exit(esp4_fini
);
473 MODULE_LICENSE("GPL");
474 MODULE_ALIAS_XFRM_TYPE(AF_INET
, XFRM_PROTO_ESP
);