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Diffstat (limited to 'net/ipv4/esp4.c')
-rw-r--r--net/ipv4/esp4.c510
1 files changed, 510 insertions, 0 deletions
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
new file mode 100644
index 000000000000..053a883247ba
--- /dev/null
+++ b/net/ipv4/esp4.c
@@ -0,0 +1,510 @@
+#include <linux/config.h>
+#include <linux/module.h>
+#include <net/ip.h>
+#include <net/xfrm.h>
+#include <net/esp.h>
+#include <asm/scatterlist.h>
+#include <linux/crypto.h>
+#include <linux/pfkeyv2.h>
+#include <linux/random.h>
+#include <net/icmp.h>
+#include <net/udp.h>
+
+/* decapsulation data for use when post-processing */
+struct esp_decap_data {
+ xfrm_address_t saddr;
+ __u16 sport;
+ __u8 proto;
+};
+
+static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+ int err;
+ struct iphdr *top_iph;
+ struct ip_esp_hdr *esph;
+ struct crypto_tfm *tfm;
+ struct esp_data *esp;
+ struct sk_buff *trailer;
+ int blksize;
+ int clen;
+ int alen;
+ int nfrags;
+
+ /* Strip IP+ESP header. */
+ __skb_pull(skb, skb->h.raw - skb->data);
+ /* Now skb is pure payload to encrypt */
+
+ err = -ENOMEM;
+
+ /* Round to block size */
+ clen = skb->len;
+
+ esp = x->data;
+ alen = esp->auth.icv_trunc_len;
+ tfm = esp->conf.tfm;
+ blksize = (crypto_tfm_alg_blocksize(tfm) + 3) & ~3;
+ clen = (clen + 2 + blksize-1)&~(blksize-1);
+ if (esp->conf.padlen)
+ clen = (clen + esp->conf.padlen-1)&~(esp->conf.padlen-1);
+
+ if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0)
+ goto error;
+
+ /* Fill padding... */
+ do {
+ int i;
+ for (i=0; i<clen-skb->len - 2; i++)
+ *(u8*)(trailer->tail + i) = i+1;
+ } while (0);
+ *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
+ pskb_put(skb, trailer, clen - skb->len);
+
+ __skb_push(skb, skb->data - skb->nh.raw);
+ top_iph = skb->nh.iph;
+ esph = (struct ip_esp_hdr *)(skb->nh.raw + top_iph->ihl*4);
+ top_iph->tot_len = htons(skb->len + alen);
+ *(u8*)(trailer->tail - 1) = top_iph->protocol;
+
+ /* this is non-NULL only with UDP Encapsulation */
+ if (x->encap) {
+ struct xfrm_encap_tmpl *encap = x->encap;
+ struct udphdr *uh;
+ u32 *udpdata32;
+
+ uh = (struct udphdr *)esph;
+ uh->source = encap->encap_sport;
+ uh->dest = encap->encap_dport;
+ uh->len = htons(skb->len + alen - top_iph->ihl*4);
+ uh->check = 0;
+
+ switch (encap->encap_type) {
+ default:
+ case UDP_ENCAP_ESPINUDP:
+ esph = (struct ip_esp_hdr *)(uh + 1);
+ break;
+ case UDP_ENCAP_ESPINUDP_NON_IKE:
+ udpdata32 = (u32 *)(uh + 1);
+ udpdata32[0] = udpdata32[1] = 0;
+ esph = (struct ip_esp_hdr *)(udpdata32 + 2);
+ break;
+ }
+
+ top_iph->protocol = IPPROTO_UDP;
+ } else
+ top_iph->protocol = IPPROTO_ESP;
+
+ esph->spi = x->id.spi;
+ esph->seq_no = htonl(++x->replay.oseq);
+
+ if (esp->conf.ivlen)
+ crypto_cipher_set_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
+
+ do {
+ struct scatterlist *sg = &esp->sgbuf[0];
+
+ if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
+ sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
+ if (!sg)
+ goto error;
+ }
+ skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
+ crypto_cipher_encrypt(tfm, sg, sg, clen);
+ if (unlikely(sg != &esp->sgbuf[0]))
+ kfree(sg);
+ } while (0);
+
+ if (esp->conf.ivlen) {
+ memcpy(esph->enc_data, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
+ crypto_cipher_get_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
+ }
+
+ if (esp->auth.icv_full_len) {
+ esp->auth.icv(esp, skb, (u8*)esph-skb->data,
+ sizeof(struct ip_esp_hdr) + esp->conf.ivlen+clen, trailer->tail);
+ pskb_put(skb, trailer, alen);
+ }
+
+ ip_send_check(top_iph);
+
+ err = 0;
+
+error:
+ return err;
+}
+
+/*
+ * Note: detecting truncated vs. non-truncated authentication data is very
+ * expensive, so we only support truncated data, which is the recommended
+ * and common case.
+ */
+static int esp_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
+{
+ struct iphdr *iph;
+ struct ip_esp_hdr *esph;
+ struct esp_data *esp = x->data;
+ struct sk_buff *trailer;
+ int blksize = crypto_tfm_alg_blocksize(esp->conf.tfm);
+ int alen = esp->auth.icv_trunc_len;
+ int elen = skb->len - sizeof(struct ip_esp_hdr) - esp->conf.ivlen - alen;
+ int nfrags;
+ int encap_len = 0;
+
+ if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr)))
+ goto out;
+
+ if (elen <= 0 || (elen & (blksize-1)))
+ goto out;
+
+ /* If integrity check is required, do this. */
+ if (esp->auth.icv_full_len) {
+ u8 sum[esp->auth.icv_full_len];
+ u8 sum1[alen];
+
+ esp->auth.icv(esp, skb, 0, skb->len-alen, sum);
+
+ if (skb_copy_bits(skb, skb->len-alen, sum1, alen))
+ BUG();
+
+ if (unlikely(memcmp(sum, sum1, alen))) {
+ x->stats.integrity_failed++;
+ goto out;
+ }
+ }
+
+ if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0)
+ goto out;
+
+ skb->ip_summed = CHECKSUM_NONE;
+
+ esph = (struct ip_esp_hdr*)skb->data;
+ iph = skb->nh.iph;
+
+ /* Get ivec. This can be wrong, check against another impls. */
+ if (esp->conf.ivlen)
+ crypto_cipher_set_iv(esp->conf.tfm, esph->enc_data, crypto_tfm_alg_ivsize(esp->conf.tfm));
+
+ {
+ u8 nexthdr[2];
+ struct scatterlist *sg = &esp->sgbuf[0];
+ u8 workbuf[60];
+ int padlen;
+
+ if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
+ sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
+ if (!sg)
+ goto out;
+ }
+ skb_to_sgvec(skb, sg, sizeof(struct ip_esp_hdr) + esp->conf.ivlen, elen);
+ crypto_cipher_decrypt(esp->conf.tfm, sg, sg, elen);
+ if (unlikely(sg != &esp->sgbuf[0]))
+ kfree(sg);
+
+ if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
+ BUG();
+
+ padlen = nexthdr[0];
+ if (padlen+2 >= elen)
+ goto out;
+
+ /* ... check padding bits here. Silly. :-) */
+
+ if (x->encap && decap && decap->decap_type) {
+ struct esp_decap_data *encap_data;
+ struct udphdr *uh = (struct udphdr *) (iph+1);
+
+ encap_data = (struct esp_decap_data *) (decap->decap_data);
+ encap_data->proto = 0;
+
+ switch (decap->decap_type) {
+ case UDP_ENCAP_ESPINUDP:
+ case UDP_ENCAP_ESPINUDP_NON_IKE:
+ encap_data->proto = AF_INET;
+ encap_data->saddr.a4 = iph->saddr;
+ encap_data->sport = uh->source;
+ encap_len = (void*)esph - (void*)uh;
+ break;
+
+ default:
+ goto out;
+ }
+ }
+
+ iph->protocol = nexthdr[1];
+ pskb_trim(skb, skb->len - alen - padlen - 2);
+ memcpy(workbuf, skb->nh.raw, iph->ihl*4);
+ skb->h.raw = skb_pull(skb, sizeof(struct ip_esp_hdr) + esp->conf.ivlen);
+ skb->nh.raw += encap_len + sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
+ memcpy(skb->nh.raw, workbuf, iph->ihl*4);
+ skb->nh.iph->tot_len = htons(skb->len);
+ }
+
+ return 0;
+
+out:
+ return -EINVAL;
+}
+
+static int esp_post_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
+{
+
+ if (x->encap) {
+ struct xfrm_encap_tmpl *encap;
+ struct esp_decap_data *decap_data;
+
+ encap = x->encap;
+ decap_data = (struct esp_decap_data *)(decap->decap_data);
+
+ /* first, make sure that the decap type == the encap type */
+ if (encap->encap_type != decap->decap_type)
+ return -EINVAL;
+
+ switch (encap->encap_type) {
+ default:
+ case UDP_ENCAP_ESPINUDP:
+ case UDP_ENCAP_ESPINUDP_NON_IKE:
+ /*
+ * 1) if the NAT-T peer's IP or port changed then
+ * advertize the change to the keying daemon.
+ * This is an inbound SA, so just compare
+ * SRC ports.
+ */
+ if (decap_data->proto == AF_INET &&
+ (decap_data->saddr.a4 != x->props.saddr.a4 ||
+ decap_data->sport != encap->encap_sport)) {
+ xfrm_address_t ipaddr;
+
+ ipaddr.a4 = decap_data->saddr.a4;
+ km_new_mapping(x, &ipaddr, decap_data->sport);
+
+ /* XXX: perhaps add an extra
+ * policy check here, to see
+ * if we should allow or
+ * reject a packet from a
+ * different source
+ * address/port.
+ */
+ }
+
+ /*
+ * 2) ignore UDP/TCP checksums in case
+ * of NAT-T in Transport Mode, or
+ * perform other post-processing fixes
+ * as per * draft-ietf-ipsec-udp-encaps-06,
+ * section 3.1.2
+ */
+ if (!x->props.mode)
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+ break;
+ }
+ }
+ return 0;
+}
+
+static u32 esp4_get_max_size(struct xfrm_state *x, int mtu)
+{
+ struct esp_data *esp = x->data;
+ u32 blksize = crypto_tfm_alg_blocksize(esp->conf.tfm);
+
+ if (x->props.mode) {
+ mtu = (mtu + 2 + blksize-1)&~(blksize-1);
+ } else {
+ /* The worst case. */
+ mtu += 2 + blksize;
+ }
+ if (esp->conf.padlen)
+ mtu = (mtu + esp->conf.padlen-1)&~(esp->conf.padlen-1);
+
+ return mtu + x->props.header_len + esp->auth.icv_trunc_len;
+}
+
+static void esp4_err(struct sk_buff *skb, u32 info)
+{
+ struct iphdr *iph = (struct iphdr*)skb->data;
+ struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2));
+ struct xfrm_state *x;
+
+ if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
+ skb->h.icmph->code != ICMP_FRAG_NEEDED)
+ return;
+
+ x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
+ if (!x)
+ return;
+ NETDEBUG(printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
+ ntohl(esph->spi), ntohl(iph->daddr)));
+ xfrm_state_put(x);
+}
+
+static void esp_destroy(struct xfrm_state *x)
+{
+ struct esp_data *esp = x->data;
+
+ if (!esp)
+ return;
+
+ if (esp->conf.tfm) {
+ crypto_free_tfm(esp->conf.tfm);
+ esp->conf.tfm = NULL;
+ }
+ if (esp->conf.ivec) {
+ kfree(esp->conf.ivec);
+ esp->conf.ivec = NULL;
+ }
+ if (esp->auth.tfm) {
+ crypto_free_tfm(esp->auth.tfm);
+ esp->auth.tfm = NULL;
+ }
+ if (esp->auth.work_icv) {
+ kfree(esp->auth.work_icv);
+ esp->auth.work_icv = NULL;
+ }
+ kfree(esp);
+}
+
+static int esp_init_state(struct xfrm_state *x, void *args)
+{
+ struct esp_data *esp = NULL;
+
+ /* null auth and encryption can have zero length keys */
+ if (x->aalg) {
+ if (x->aalg->alg_key_len > 512)
+ goto error;
+ }
+ if (x->ealg == NULL)
+ goto error;
+
+ esp = kmalloc(sizeof(*esp), GFP_KERNEL);
+ if (esp == NULL)
+ return -ENOMEM;
+
+ memset(esp, 0, sizeof(*esp));
+
+ if (x->aalg) {
+ struct xfrm_algo_desc *aalg_desc;
+
+ esp->auth.key = x->aalg->alg_key;
+ esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
+ esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
+ if (esp->auth.tfm == NULL)
+ goto error;
+ esp->auth.icv = esp_hmac_digest;
+
+ aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
+ BUG_ON(!aalg_desc);
+
+ if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
+ crypto_tfm_alg_digestsize(esp->auth.tfm)) {
+ NETDEBUG(printk(KERN_INFO "ESP: %s digestsize %u != %hu\n",
+ x->aalg->alg_name,
+ crypto_tfm_alg_digestsize(esp->auth.tfm),
+ aalg_desc->uinfo.auth.icv_fullbits/8));
+ goto error;
+ }
+
+ esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
+ esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
+
+ esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
+ if (!esp->auth.work_icv)
+ goto error;
+ }
+ esp->conf.key = x->ealg->alg_key;
+ esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
+ if (x->props.ealgo == SADB_EALG_NULL)
+ esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_ECB);
+ else
+ esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_CBC);
+ if (esp->conf.tfm == NULL)
+ goto error;
+ esp->conf.ivlen = crypto_tfm_alg_ivsize(esp->conf.tfm);
+ esp->conf.padlen = 0;
+ if (esp->conf.ivlen) {
+ esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
+ if (unlikely(esp->conf.ivec == NULL))
+ goto error;
+ get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
+ }
+ if (crypto_cipher_setkey(esp->conf.tfm, esp->conf.key, esp->conf.key_len))
+ goto error;
+ x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
+ if (x->props.mode)
+ x->props.header_len += sizeof(struct iphdr);
+ if (x->encap) {
+ struct xfrm_encap_tmpl *encap = x->encap;
+
+ switch (encap->encap_type) {
+ default:
+ goto error;
+ case UDP_ENCAP_ESPINUDP:
+ x->props.header_len += sizeof(struct udphdr);
+ break;
+ case UDP_ENCAP_ESPINUDP_NON_IKE:
+ x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
+ break;
+ }
+ }
+ x->data = esp;
+ x->props.trailer_len = esp4_get_max_size(x, 0) - x->props.header_len;
+ return 0;
+
+error:
+ x->data = esp;
+ esp_destroy(x);
+ x->data = NULL;
+ return -EINVAL;
+}
+
+static struct xfrm_type esp_type =
+{
+ .description = "ESP4",
+ .owner = THIS_MODULE,
+ .proto = IPPROTO_ESP,
+ .init_state = esp_init_state,
+ .destructor = esp_destroy,
+ .get_max_size = esp4_get_max_size,
+ .input = esp_input,
+ .post_input = esp_post_input,
+ .output = esp_output
+};
+
+static struct net_protocol esp4_protocol = {
+ .handler = xfrm4_rcv,
+ .err_handler = esp4_err,
+ .no_policy = 1,
+};
+
+static int __init esp4_init(void)
+{
+ struct xfrm_decap_state decap;
+
+ if (sizeof(struct esp_decap_data) <
+ sizeof(decap.decap_data)) {
+ extern void decap_data_too_small(void);
+
+ decap_data_too_small();
+ }
+
+ if (xfrm_register_type(&esp_type, AF_INET) < 0) {
+ printk(KERN_INFO "ip esp init: can't add xfrm type\n");
+ return -EAGAIN;
+ }
+ if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
+ printk(KERN_INFO "ip esp init: can't add protocol\n");
+ xfrm_unregister_type(&esp_type, AF_INET);
+ return -EAGAIN;
+ }
+ return 0;
+}
+
+static void __exit esp4_fini(void)
+{
+ if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
+ printk(KERN_INFO "ip esp close: can't remove protocol\n");
+ if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
+ printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
+}
+
+module_init(esp4_init);
+module_exit(esp4_fini);
+MODULE_LICENSE("GPL");