--- /dev/null
+/*
+ * SR-IPv6 implementation -- HMAC functions
+ *
+ * Author:
+ * David Lebrun <david.lebrun@uclouvain.be>
+ *
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/in6.h>
+#include <linux/icmpv6.h>
+#include <linux/mroute6.h>
+#include <linux/slab.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv6.h>
+
+#include <net/sock.h>
+#include <net/snmp.h>
+
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/transp_v6.h>
+#include <net/rawv6.h>
+#include <net/ndisc.h>
+#include <net/ip6_route.h>
+#include <net/addrconf.h>
+#include <net/xfrm.h>
+
+#include <linux/cryptohash.h>
+#include <crypto/hash.h>
+#include <crypto/sha.h>
+#include <net/seg6.h>
+#include <net/genetlink.h>
+#include <net/seg6_hmac.h>
+#include <linux/random.h>
+
+static char * __percpu *hmac_ring;
+
+static int seg6_hmac_cmpfn(struct rhashtable_compare_arg *arg, const void *obj)
+{
+ const struct seg6_hmac_info *hinfo = obj;
+
+ return (hinfo->hmackeyid != *(__u32 *)arg->key);
+}
+
+static inline void seg6_hinfo_release(struct seg6_hmac_info *hinfo)
+{
+ kfree_rcu(hinfo, rcu);
+}
+
+static void seg6_free_hi(void *ptr, void *arg)
+{
+ struct seg6_hmac_info *hinfo = (struct seg6_hmac_info *)ptr;
+
+ if (hinfo)
+ seg6_hinfo_release(hinfo);
+}
+
+static const struct rhashtable_params rht_params = {
+ .head_offset = offsetof(struct seg6_hmac_info, node),
+ .key_offset = offsetof(struct seg6_hmac_info, hmackeyid),
+ .key_len = sizeof(u32),
+ .automatic_shrinking = true,
+ .obj_cmpfn = seg6_hmac_cmpfn,
+};
+
+static struct seg6_hmac_algo hmac_algos[] = {
+ {
+ .alg_id = SEG6_HMAC_ALGO_SHA1,
+ .name = "hmac(sha1)",
+ },
+ {
+ .alg_id = SEG6_HMAC_ALGO_SHA256,
+ .name = "hmac(sha256)",
+ },
+};
+
+static struct sr6_tlv_hmac *seg6_get_tlv_hmac(struct ipv6_sr_hdr *srh)
+{
+ struct sr6_tlv_hmac *tlv;
+
+ if (srh->hdrlen < (srh->first_segment + 1) * 2 + 5)
+ return NULL;
+
+ if (!sr_has_hmac(srh))
+ return NULL;
+
+ tlv = (struct sr6_tlv_hmac *)
+ ((char *)srh + ((srh->hdrlen + 1) << 3) - 40);
+
+ if (tlv->tlvhdr.type != SR6_TLV_HMAC || tlv->tlvhdr.len != 38)
+ return NULL;
+
+ return tlv;
+}
+
+static struct seg6_hmac_algo *__hmac_get_algo(u8 alg_id)
+{
+ struct seg6_hmac_algo *algo;
+ int i, alg_count;
+
+ alg_count = sizeof(hmac_algos) / sizeof(struct seg6_hmac_algo);
+ for (i = 0; i < alg_count; i++) {
+ algo = &hmac_algos[i];
+ if (algo->alg_id == alg_id)
+ return algo;
+ }
+
+ return NULL;
+}
+
+static int __do_hmac(struct seg6_hmac_info *hinfo, const char *text, u8 psize,
+ u8 *output, int outlen)
+{
+ struct seg6_hmac_algo *algo;
+ struct crypto_shash *tfm;
+ struct shash_desc *shash;
+ int ret, dgsize;
+
+ algo = __hmac_get_algo(hinfo->alg_id);
+ if (!algo)
+ return -ENOENT;
+
+ tfm = *this_cpu_ptr(algo->tfms);
+
+ dgsize = crypto_shash_digestsize(tfm);
+ if (dgsize > outlen) {
+ pr_debug("sr-ipv6: __do_hmac: digest size too big (%d / %d)\n",
+ dgsize, outlen);
+ return -ENOMEM;
+ }
+
+ ret = crypto_shash_setkey(tfm, hinfo->secret, hinfo->slen);
+ if (ret < 0) {
+ pr_debug("sr-ipv6: crypto_shash_setkey failed: err %d\n", ret);
+ goto failed;
+ }
+
+ shash = *this_cpu_ptr(algo->shashs);
+ shash->tfm = tfm;
+
+ ret = crypto_shash_digest(shash, text, psize, output);
+ if (ret < 0) {
+ pr_debug("sr-ipv6: crypto_shash_digest failed: err %d\n", ret);
+ goto failed;
+ }
+
+ return dgsize;
+
+failed:
+ return ret;
+}
+
+int seg6_hmac_compute(struct seg6_hmac_info *hinfo, struct ipv6_sr_hdr *hdr,
+ struct in6_addr *saddr, u8 *output)
+{
+ __be32 hmackeyid = cpu_to_be32(hinfo->hmackeyid);
+ u8 tmp_out[SEG6_HMAC_MAX_DIGESTSIZE];
+ int plen, i, dgsize, wrsize;
+ char *ring, *off;
+
+ /* a 160-byte buffer for digest output allows to store highest known
+ * hash function (RadioGatun) with up to 1216 bits
+ */
+
+ /* saddr(16) + first_seg(1) + cleanup(1) + keyid(4) + seglist(16n) */
+ plen = 16 + 1 + 1 + 4 + (hdr->first_segment + 1) * 16;
+
+ /* this limit allows for 14 segments */
+ if (plen >= SEG6_HMAC_RING_SIZE)
+ return -EMSGSIZE;
+
+ /* Let's build the HMAC text on the ring buffer. The text is composed
+ * as follows, in order:
+ *
+ * 1. Source IPv6 address (128 bits)
+ * 2. first_segment value (8 bits)
+ * 3. cleanup flag (8 bits: highest bit is cleanup value, others are 0)
+ * 4. HMAC Key ID (32 bits)
+ * 5. All segments in the segments list (n * 128 bits)
+ */
+
+ local_bh_disable();
+ ring = *this_cpu_ptr(hmac_ring);
+ off = ring;
+
+ /* source address */
+ memcpy(off, saddr, 16);
+ off += 16;
+
+ /* first_segment value */
+ *off++ = hdr->first_segment;
+
+ /* cleanup flag */
+ *off++ = !!(sr_has_cleanup(hdr)) << 7;
+
+ /* HMAC Key ID */
+ memcpy(off, &hmackeyid, 4);
+ off += 4;
+
+ /* all segments in the list */
+ for (i = 0; i < hdr->first_segment + 1; i++) {
+ memcpy(off, hdr->segments + i, 16);
+ off += 16;
+ }
+
+ dgsize = __do_hmac(hinfo, ring, plen, tmp_out,
+ SEG6_HMAC_MAX_DIGESTSIZE);
+ local_bh_enable();
+
+ if (dgsize < 0)
+ return dgsize;
+
+ wrsize = SEG6_HMAC_FIELD_LEN;
+ if (wrsize > dgsize)
+ wrsize = dgsize;
+
+ memset(output, 0, SEG6_HMAC_FIELD_LEN);
+ memcpy(output, tmp_out, wrsize);
+
+ return 0;
+}
+EXPORT_SYMBOL(seg6_hmac_compute);
+
+/* checks if an incoming SR-enabled packet's HMAC status matches
+ * the incoming policy.
+ *
+ * called with rcu_read_lock()
+ */
+bool seg6_hmac_validate_skb(struct sk_buff *skb)
+{
+ u8 hmac_output[SEG6_HMAC_FIELD_LEN];
+ struct net *net = dev_net(skb->dev);
+ struct seg6_hmac_info *hinfo;
+ struct sr6_tlv_hmac *tlv;
+ struct ipv6_sr_hdr *srh;
+ struct inet6_dev *idev;
+
+ idev = __in6_dev_get(skb->dev);
+
+ srh = (struct ipv6_sr_hdr *)skb_transport_header(skb);
+
+ tlv = seg6_get_tlv_hmac(srh);
+
+ /* mandatory check but no tlv */
+ if (idev->cnf.seg6_require_hmac > 0 && !tlv)
+ return false;
+
+ /* no check */
+ if (idev->cnf.seg6_require_hmac < 0)
+ return true;
+
+ /* check only if present */
+ if (idev->cnf.seg6_require_hmac == 0 && !tlv)
+ return true;
+
+ /* now, seg6_require_hmac >= 0 && tlv */
+
+ hinfo = seg6_hmac_info_lookup(net, be32_to_cpu(tlv->hmackeyid));
+ if (!hinfo)
+ return false;
+
+ if (seg6_hmac_compute(hinfo, srh, &ipv6_hdr(skb)->saddr, hmac_output))
+ return false;
+
+ if (memcmp(hmac_output, tlv->hmac, SEG6_HMAC_FIELD_LEN) != 0)
+ return false;
+
+ return true;
+}
+EXPORT_SYMBOL(seg6_hmac_validate_skb);
+
+/* called with rcu_read_lock() */
+struct seg6_hmac_info *seg6_hmac_info_lookup(struct net *net, u32 key)
+{
+ struct seg6_pernet_data *sdata = seg6_pernet(net);
+ struct seg6_hmac_info *hinfo;
+
+ hinfo = rhashtable_lookup_fast(&sdata->hmac_infos, &key, rht_params);
+
+ return hinfo;
+}
+EXPORT_SYMBOL(seg6_hmac_info_lookup);
+
+int seg6_hmac_info_add(struct net *net, u32 key, struct seg6_hmac_info *hinfo)
+{
+ struct seg6_pernet_data *sdata = seg6_pernet(net);
+ int err;
+
+ err = rhashtable_lookup_insert_fast(&sdata->hmac_infos, &hinfo->node,
+ rht_params);
+
+ return err;
+}
+EXPORT_SYMBOL(seg6_hmac_info_add);
+
+int seg6_hmac_info_del(struct net *net, u32 key)
+{
+ struct seg6_pernet_data *sdata = seg6_pernet(net);
+ struct seg6_hmac_info *hinfo;
+ int err = -ENOENT;
+
+ hinfo = rhashtable_lookup_fast(&sdata->hmac_infos, &key, rht_params);
+ if (!hinfo)
+ goto out;
+
+ err = rhashtable_remove_fast(&sdata->hmac_infos, &hinfo->node,
+ rht_params);
+ if (err)
+ goto out;
+
+ seg6_hinfo_release(hinfo);
+
+out:
+ return err;
+}
+EXPORT_SYMBOL(seg6_hmac_info_del);
+
+int seg6_push_hmac(struct net *net, struct in6_addr *saddr,
+ struct ipv6_sr_hdr *srh)
+{
+ struct seg6_hmac_info *hinfo;
+ struct sr6_tlv_hmac *tlv;
+ int err = -ENOENT;
+
+ tlv = seg6_get_tlv_hmac(srh);
+ if (!tlv)
+ return -EINVAL;
+
+ rcu_read_lock();
+
+ hinfo = seg6_hmac_info_lookup(net, be32_to_cpu(tlv->hmackeyid));
+ if (!hinfo)
+ goto out;
+
+ memset(tlv->hmac, 0, SEG6_HMAC_FIELD_LEN);
+ err = seg6_hmac_compute(hinfo, srh, saddr, tlv->hmac);
+
+out:
+ rcu_read_unlock();
+ return err;
+}
+EXPORT_SYMBOL(seg6_push_hmac);
+
+static int seg6_hmac_init_ring(void)
+{
+ int i;
+
+ hmac_ring = alloc_percpu(char *);
+
+ if (!hmac_ring)
+ return -ENOMEM;
+
+ for_each_possible_cpu(i) {
+ char *ring = kzalloc(SEG6_HMAC_RING_SIZE, GFP_KERNEL);
+
+ if (!ring)
+ return -ENOMEM;
+
+ *per_cpu_ptr(hmac_ring, i) = ring;
+ }
+
+ return 0;
+}
+
+static int seg6_hmac_init_algo(void)
+{
+ struct seg6_hmac_algo *algo;
+ struct crypto_shash *tfm;
+ struct shash_desc *shash;
+ int i, alg_count, cpu;
+
+ alg_count = sizeof(hmac_algos) / sizeof(struct seg6_hmac_algo);
+
+ for (i = 0; i < alg_count; i++) {
+ struct crypto_shash **p_tfm;
+ int shsize;
+
+ algo = &hmac_algos[i];
+ algo->tfms = alloc_percpu(struct crypto_shash *);
+ if (!algo->tfms)
+ return -ENOMEM;
+
+ for_each_possible_cpu(cpu) {
+ tfm = crypto_alloc_shash(algo->name, 0, GFP_KERNEL);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+ p_tfm = per_cpu_ptr(algo->tfms, cpu);
+ *p_tfm = tfm;
+ }
+
+ p_tfm = this_cpu_ptr(algo->tfms);
+ tfm = *p_tfm;
+
+ shsize = sizeof(*shash) + crypto_shash_descsize(tfm);
+
+ algo->shashs = alloc_percpu(struct shash_desc *);
+ if (!algo->shashs)
+ return -ENOMEM;
+
+ for_each_possible_cpu(cpu) {
+ shash = kzalloc(shsize, GFP_KERNEL);
+ if (!shash)
+ return -ENOMEM;
+ *per_cpu_ptr(algo->shashs, cpu) = shash;
+ }
+ }
+
+ return 0;
+}
+
+int __init seg6_hmac_init(void)
+{
+ int ret;
+
+ ret = seg6_hmac_init_ring();
+ if (ret < 0)
+ goto out;
+
+ ret = seg6_hmac_init_algo();
+
+out:
+ return ret;
+}
+EXPORT_SYMBOL(seg6_hmac_init);
+
+int __net_init seg6_hmac_net_init(struct net *net)
+{
+ struct seg6_pernet_data *sdata = seg6_pernet(net);
+
+ rhashtable_init(&sdata->hmac_infos, &rht_params);
+
+ return 0;
+}
+EXPORT_SYMBOL(seg6_hmac_net_init);
+
+void seg6_hmac_exit(void)
+{
+ struct seg6_hmac_algo *algo = NULL;
+ int i, alg_count, cpu;
+
+ for_each_possible_cpu(i) {
+ char *ring = *per_cpu_ptr(hmac_ring, i);
+
+ kfree(ring);
+ }
+ free_percpu(hmac_ring);
+
+ alg_count = sizeof(hmac_algos) / sizeof(struct seg6_hmac_algo);
+ for (i = 0; i < alg_count; i++) {
+ algo = &hmac_algos[i];
+ for_each_possible_cpu(cpu) {
+ struct crypto_shash *tfm;
+ struct shash_desc *shash;
+
+ shash = *per_cpu_ptr(algo->shashs, cpu);
+ kfree(shash);
+ tfm = *per_cpu_ptr(algo->tfms, cpu);
+ crypto_free_shash(tfm);
+ }
+ free_percpu(algo->tfms);
+ free_percpu(algo->shashs);
+ }
+}
+EXPORT_SYMBOL(seg6_hmac_exit);
+
+void __net_exit seg6_hmac_net_exit(struct net *net)
+{
+ struct seg6_pernet_data *sdata = seg6_pernet(net);
+
+ rhashtable_free_and_destroy(&sdata->hmac_infos, seg6_free_hi, NULL);
+}
+EXPORT_SYMBOL(seg6_hmac_net_exit);
projects / users / hch / configfs.git / commitdiff