mac802154: add llsec encryption method
Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Phoebe Buckheister
David S. Miller
parent
5d637d5aab
commit
03556e4d0d
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@ -527,3 +527,256 @@ int mac802154_llsec_seclevel_del(struct mac802154_llsec *sec,
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return 0;
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}
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static int llsec_recover_addr(struct mac802154_llsec *sec,
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struct ieee802154_addr *addr)
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{
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__le16 caddr = sec->params.coord_shortaddr;
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addr->pan_id = sec->params.pan_id;
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if (caddr == cpu_to_le16(IEEE802154_ADDR_BROADCAST)) {
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return -EINVAL;
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} else if (caddr == cpu_to_le16(IEEE802154_ADDR_UNDEF)) {
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addr->extended_addr = sec->params.coord_hwaddr;
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addr->mode = IEEE802154_ADDR_LONG;
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} else {
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addr->short_addr = sec->params.coord_shortaddr;
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addr->mode = IEEE802154_ADDR_SHORT;
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}
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return 0;
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}
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static struct mac802154_llsec_key*
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llsec_lookup_key(struct mac802154_llsec *sec,
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const struct ieee802154_hdr *hdr,
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const struct ieee802154_addr *addr,
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struct ieee802154_llsec_key_id *key_id)
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{
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struct ieee802154_addr devaddr = *addr;
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u8 key_id_mode = hdr->sec.key_id_mode;
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struct ieee802154_llsec_key_entry *key_entry;
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struct mac802154_llsec_key *key;
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if (key_id_mode == IEEE802154_SCF_KEY_IMPLICIT &&
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devaddr.mode == IEEE802154_ADDR_NONE) {
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if (hdr->fc.type == IEEE802154_FC_TYPE_BEACON) {
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devaddr.extended_addr = sec->params.coord_hwaddr;
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devaddr.mode = IEEE802154_ADDR_LONG;
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} else if (llsec_recover_addr(sec, &devaddr) < 0) {
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return NULL;
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}
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}
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list_for_each_entry_rcu(key_entry, &sec->table.keys, list) {
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const struct ieee802154_llsec_key_id *id = &key_entry->id;
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if (!(key_entry->key->frame_types & BIT(hdr->fc.type)))
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continue;
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if (id->mode != key_id_mode)
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continue;
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if (key_id_mode == IEEE802154_SCF_KEY_IMPLICIT) {
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if (ieee802154_addr_equal(&devaddr, &id->device_addr))
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goto found;
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} else {
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if (id->id != hdr->sec.key_id)
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continue;
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if ((key_id_mode == IEEE802154_SCF_KEY_INDEX) ||
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(key_id_mode == IEEE802154_SCF_KEY_SHORT_INDEX &&
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id->short_source == hdr->sec.short_src) ||
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(key_id_mode == IEEE802154_SCF_KEY_HW_INDEX &&
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id->extended_source == hdr->sec.extended_src))
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goto found;
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}
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}
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return NULL;
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found:
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key = container_of(key_entry->key, struct mac802154_llsec_key, key);
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if (key_id)
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*key_id = key_entry->id;
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return llsec_key_get(key);
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}
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static void llsec_geniv(u8 iv[16], __le64 addr,
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const struct ieee802154_sechdr *sec)
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{
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__be64 addr_bytes = (__force __be64) swab64((__force u64) addr);
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__be32 frame_counter = (__force __be32) swab32((__force u32) sec->frame_counter);
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iv[0] = 1; /* L' = L - 1 = 1 */
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memcpy(iv + 1, &addr_bytes, sizeof(addr_bytes));
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memcpy(iv + 9, &frame_counter, sizeof(frame_counter));
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iv[13] = sec->level;
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iv[14] = 0;
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iv[15] = 1;
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}
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static int
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llsec_do_encrypt_unauth(struct sk_buff *skb, const struct mac802154_llsec *sec,
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const struct ieee802154_hdr *hdr,
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struct mac802154_llsec_key *key)
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{
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u8 iv[16];
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struct scatterlist src;
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struct blkcipher_desc req = {
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.tfm = key->tfm0,
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.info = iv,
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.flags = 0,
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};
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llsec_geniv(iv, sec->params.hwaddr, &hdr->sec);
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sg_init_one(&src, skb->data, skb->len);
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return crypto_blkcipher_encrypt_iv(&req, &src, &src, skb->len);
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}
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static struct crypto_aead*
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llsec_tfm_by_len(struct mac802154_llsec_key *key, int authlen)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(key->tfm); i++)
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if (crypto_aead_authsize(key->tfm[i]) == authlen)
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return key->tfm[i];
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BUG();
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}
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static int
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llsec_do_encrypt_auth(struct sk_buff *skb, const struct mac802154_llsec *sec,
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const struct ieee802154_hdr *hdr,
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struct mac802154_llsec_key *key)
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{
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u8 iv[16];
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unsigned char *data;
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int authlen, assoclen, datalen, rc;
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struct scatterlist src, assoc[2], dst[2];
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struct aead_request *req;
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authlen = ieee802154_sechdr_authtag_len(&hdr->sec);
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llsec_geniv(iv, sec->params.hwaddr, &hdr->sec);
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req = aead_request_alloc(llsec_tfm_by_len(key, authlen), GFP_ATOMIC);
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if (!req)
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return -ENOMEM;
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sg_init_table(assoc, 2);
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sg_set_buf(&assoc[0], skb_mac_header(skb), skb->mac_len);
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assoclen = skb->mac_len;
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data = skb_mac_header(skb) + skb->mac_len;
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datalen = skb_tail_pointer(skb) - data;
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if (hdr->sec.level & IEEE802154_SCF_SECLEVEL_ENC) {
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sg_set_buf(&assoc[1], data, 0);
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} else {
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sg_set_buf(&assoc[1], data, datalen);
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assoclen += datalen;
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datalen = 0;
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}
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sg_init_one(&src, data, datalen);
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sg_init_table(dst, 2);
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sg_set_buf(&dst[0], data, datalen);
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sg_set_buf(&dst[1], skb_put(skb, authlen), authlen);
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aead_request_set_callback(req, 0, NULL, NULL);
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aead_request_set_assoc(req, assoc, assoclen);
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aead_request_set_crypt(req, &src, dst, datalen, iv);
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rc = crypto_aead_encrypt(req);
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kfree(req);
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return rc;
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}
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static int llsec_do_encrypt(struct sk_buff *skb,
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const struct mac802154_llsec *sec,
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const struct ieee802154_hdr *hdr,
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struct mac802154_llsec_key *key)
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{
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if (hdr->sec.level == IEEE802154_SCF_SECLEVEL_ENC)
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return llsec_do_encrypt_unauth(skb, sec, hdr, key);
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else
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return llsec_do_encrypt_auth(skb, sec, hdr, key);
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}
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int mac802154_llsec_encrypt(struct mac802154_llsec *sec, struct sk_buff *skb)
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{
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struct ieee802154_hdr hdr;
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int rc, authlen, hlen;
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struct mac802154_llsec_key *key;
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u32 frame_ctr;
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hlen = ieee802154_hdr_pull(skb, &hdr);
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if (hlen < 0 || hdr.fc.type != IEEE802154_FC_TYPE_DATA)
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return -EINVAL;
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if (!hdr.fc.security_enabled || hdr.sec.level == 0) {
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skb_push(skb, hlen);
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return 0;
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}
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authlen = ieee802154_sechdr_authtag_len(&hdr.sec);
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if (skb->len + hlen + authlen + IEEE802154_MFR_SIZE > IEEE802154_MTU)
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return -EMSGSIZE;
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rcu_read_lock();
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read_lock_bh(&sec->lock);
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if (!sec->params.enabled) {
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rc = -EINVAL;
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goto fail_read;
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}
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key = llsec_lookup_key(sec, &hdr, &hdr.dest, NULL);
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if (!key) {
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rc = -ENOKEY;
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goto fail_read;
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}
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read_unlock_bh(&sec->lock);
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write_lock_bh(&sec->lock);
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frame_ctr = be32_to_cpu(sec->params.frame_counter);
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hdr.sec.frame_counter = cpu_to_le32(frame_ctr);
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if (frame_ctr == 0xFFFFFFFF) {
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write_unlock_bh(&sec->lock);
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llsec_key_put(key);
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rc = -EOVERFLOW;
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goto fail;
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}
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sec->params.frame_counter = cpu_to_be32(frame_ctr + 1);
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write_unlock_bh(&sec->lock);
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rcu_read_unlock();
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skb->mac_len = ieee802154_hdr_push(skb, &hdr);
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skb_reset_mac_header(skb);
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rc = llsec_do_encrypt(skb, sec, &hdr, key);
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llsec_key_put(key);
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return rc < 0 ? rc : 0;
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fail_read:
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read_unlock(&sec->lock);
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fail:
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rcu_read_unlock();
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return rc;
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}
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@ -102,4 +102,6 @@ int mac802154_llsec_seclevel_add(struct mac802154_llsec *sec,
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int mac802154_llsec_seclevel_del(struct mac802154_llsec *sec,
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const struct ieee802154_llsec_seclevel *sl);
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int mac802154_llsec_encrypt(struct mac802154_llsec *sec, struct sk_buff *skb);
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#endif /* MAC802154_LLSEC_H */
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