From 03556e4d0dbbbf4af9df76f4a3839c86f6afb015 Mon Sep 17 00:00:00 2001 From: Phoebe Buckheister Date: Fri, 16 May 2014 17:46:38 +0200 Subject: [PATCH] mac802154: add llsec encryption method Signed-off-by: Phoebe Buckheister Signed-off-by: David S. Miller --- net/mac802154/llsec.c | 253 ++++++++++++++++++++++++++++++++++++++++++ net/mac802154/llsec.h | 2 + 2 files changed, 255 insertions(+) diff --git a/net/mac802154/llsec.c b/net/mac802154/llsec.c index a210d1eb65a9..2a4b68e2a934 100644 --- a/net/mac802154/llsec.c +++ b/net/mac802154/llsec.c @@ -527,3 +527,256 @@ int mac802154_llsec_seclevel_del(struct mac802154_llsec *sec, return 0; } + + + +static int llsec_recover_addr(struct mac802154_llsec *sec, + struct ieee802154_addr *addr) +{ + __le16 caddr = sec->params.coord_shortaddr; + addr->pan_id = sec->params.pan_id; + + if (caddr == cpu_to_le16(IEEE802154_ADDR_BROADCAST)) { + return -EINVAL; + } else if (caddr == cpu_to_le16(IEEE802154_ADDR_UNDEF)) { + addr->extended_addr = sec->params.coord_hwaddr; + addr->mode = IEEE802154_ADDR_LONG; + } else { + addr->short_addr = sec->params.coord_shortaddr; + addr->mode = IEEE802154_ADDR_SHORT; + } + + return 0; +} + +static struct mac802154_llsec_key* +llsec_lookup_key(struct mac802154_llsec *sec, + const struct ieee802154_hdr *hdr, + const struct ieee802154_addr *addr, + struct ieee802154_llsec_key_id *key_id) +{ + struct ieee802154_addr devaddr = *addr; + u8 key_id_mode = hdr->sec.key_id_mode; + struct ieee802154_llsec_key_entry *key_entry; + struct mac802154_llsec_key *key; + + if (key_id_mode == IEEE802154_SCF_KEY_IMPLICIT && + devaddr.mode == IEEE802154_ADDR_NONE) { + if (hdr->fc.type == IEEE802154_FC_TYPE_BEACON) { + devaddr.extended_addr = sec->params.coord_hwaddr; + devaddr.mode = IEEE802154_ADDR_LONG; + } else if (llsec_recover_addr(sec, &devaddr) < 0) { + return NULL; + } + } + + list_for_each_entry_rcu(key_entry, &sec->table.keys, list) { + const struct ieee802154_llsec_key_id *id = &key_entry->id; + + if (!(key_entry->key->frame_types & BIT(hdr->fc.type))) + continue; + + if (id->mode != key_id_mode) + continue; + + if (key_id_mode == IEEE802154_SCF_KEY_IMPLICIT) { + if (ieee802154_addr_equal(&devaddr, &id->device_addr)) + goto found; + } else { + if (id->id != hdr->sec.key_id) + continue; + + if ((key_id_mode == IEEE802154_SCF_KEY_INDEX) || + (key_id_mode == IEEE802154_SCF_KEY_SHORT_INDEX && + id->short_source == hdr->sec.short_src) || + (key_id_mode == IEEE802154_SCF_KEY_HW_INDEX && + id->extended_source == hdr->sec.extended_src)) + goto found; + } + } + + return NULL; + +found: + key = container_of(key_entry->key, struct mac802154_llsec_key, key); + if (key_id) + *key_id = key_entry->id; + return llsec_key_get(key); +} + + +static void llsec_geniv(u8 iv[16], __le64 addr, + const struct ieee802154_sechdr *sec) +{ + __be64 addr_bytes = (__force __be64) swab64((__force u64) addr); + __be32 frame_counter = (__force __be32) swab32((__force u32) sec->frame_counter); + + iv[0] = 1; /* L' = L - 1 = 1 */ + memcpy(iv + 1, &addr_bytes, sizeof(addr_bytes)); + memcpy(iv + 9, &frame_counter, sizeof(frame_counter)); + iv[13] = sec->level; + iv[14] = 0; + iv[15] = 1; +} + +static int +llsec_do_encrypt_unauth(struct sk_buff *skb, const struct mac802154_llsec *sec, + const struct ieee802154_hdr *hdr, + struct mac802154_llsec_key *key) +{ + u8 iv[16]; + struct scatterlist src; + struct blkcipher_desc req = { + .tfm = key->tfm0, + .info = iv, + .flags = 0, + }; + + llsec_geniv(iv, sec->params.hwaddr, &hdr->sec); + sg_init_one(&src, skb->data, skb->len); + return crypto_blkcipher_encrypt_iv(&req, &src, &src, skb->len); +} + +static struct crypto_aead* +llsec_tfm_by_len(struct mac802154_llsec_key *key, int authlen) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(key->tfm); i++) + if (crypto_aead_authsize(key->tfm[i]) == authlen) + return key->tfm[i]; + + BUG(); +} + +static int +llsec_do_encrypt_auth(struct sk_buff *skb, const struct mac802154_llsec *sec, + const struct ieee802154_hdr *hdr, + struct mac802154_llsec_key *key) +{ + u8 iv[16]; + unsigned char *data; + int authlen, assoclen, datalen, rc; + struct scatterlist src, assoc[2], dst[2]; + struct aead_request *req; + + authlen = ieee802154_sechdr_authtag_len(&hdr->sec); + llsec_geniv(iv, sec->params.hwaddr, &hdr->sec); + + req = aead_request_alloc(llsec_tfm_by_len(key, authlen), GFP_ATOMIC); + if (!req) + return -ENOMEM; + + sg_init_table(assoc, 2); + sg_set_buf(&assoc[0], skb_mac_header(skb), skb->mac_len); + assoclen = skb->mac_len; + + data = skb_mac_header(skb) + skb->mac_len; + datalen = skb_tail_pointer(skb) - data; + + if (hdr->sec.level & IEEE802154_SCF_SECLEVEL_ENC) { + sg_set_buf(&assoc[1], data, 0); + } else { + sg_set_buf(&assoc[1], data, datalen); + assoclen += datalen; + datalen = 0; + } + + sg_init_one(&src, data, datalen); + + sg_init_table(dst, 2); + sg_set_buf(&dst[0], data, datalen); + sg_set_buf(&dst[1], skb_put(skb, authlen), authlen); + + aead_request_set_callback(req, 0, NULL, NULL); + aead_request_set_assoc(req, assoc, assoclen); + aead_request_set_crypt(req, &src, dst, datalen, iv); + + rc = crypto_aead_encrypt(req); + + kfree(req); + + return rc; +} + +static int llsec_do_encrypt(struct sk_buff *skb, + const struct mac802154_llsec *sec, + const struct ieee802154_hdr *hdr, + struct mac802154_llsec_key *key) +{ + if (hdr->sec.level == IEEE802154_SCF_SECLEVEL_ENC) + return llsec_do_encrypt_unauth(skb, sec, hdr, key); + else + return llsec_do_encrypt_auth(skb, sec, hdr, key); +} + +int mac802154_llsec_encrypt(struct mac802154_llsec *sec, struct sk_buff *skb) +{ + struct ieee802154_hdr hdr; + int rc, authlen, hlen; + struct mac802154_llsec_key *key; + u32 frame_ctr; + + hlen = ieee802154_hdr_pull(skb, &hdr); + + if (hlen < 0 || hdr.fc.type != IEEE802154_FC_TYPE_DATA) + return -EINVAL; + + if (!hdr.fc.security_enabled || hdr.sec.level == 0) { + skb_push(skb, hlen); + return 0; + } + + authlen = ieee802154_sechdr_authtag_len(&hdr.sec); + + if (skb->len + hlen + authlen + IEEE802154_MFR_SIZE > IEEE802154_MTU) + return -EMSGSIZE; + + rcu_read_lock(); + + read_lock_bh(&sec->lock); + + if (!sec->params.enabled) { + rc = -EINVAL; + goto fail_read; + } + + key = llsec_lookup_key(sec, &hdr, &hdr.dest, NULL); + if (!key) { + rc = -ENOKEY; + goto fail_read; + } + + read_unlock_bh(&sec->lock); + + write_lock_bh(&sec->lock); + + frame_ctr = be32_to_cpu(sec->params.frame_counter); + hdr.sec.frame_counter = cpu_to_le32(frame_ctr); + if (frame_ctr == 0xFFFFFFFF) { + write_unlock_bh(&sec->lock); + llsec_key_put(key); + rc = -EOVERFLOW; + goto fail; + } + + sec->params.frame_counter = cpu_to_be32(frame_ctr + 1); + + write_unlock_bh(&sec->lock); + + rcu_read_unlock(); + + skb->mac_len = ieee802154_hdr_push(skb, &hdr); + skb_reset_mac_header(skb); + + rc = llsec_do_encrypt(skb, sec, &hdr, key); + llsec_key_put(key); + + return rc < 0 ? rc : 0; + +fail_read: + read_unlock(&sec->lock); +fail: + rcu_read_unlock(); + return rc; +} diff --git a/net/mac802154/llsec.h b/net/mac802154/llsec.h index 65c1dd4ad5ce..083055b3b795 100644 --- a/net/mac802154/llsec.h +++ b/net/mac802154/llsec.h @@ -102,4 +102,6 @@ int mac802154_llsec_seclevel_add(struct mac802154_llsec *sec, int mac802154_llsec_seclevel_del(struct mac802154_llsec *sec, const struct ieee802154_llsec_seclevel *sl); +int mac802154_llsec_encrypt(struct mac802154_llsec *sec, struct sk_buff *skb); + #endif /* MAC802154_LLSEC_H */ -- 2.20.1