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 2014-05-16 17:46:38 +02:00 committed by David S. Miller
parent 5d637d5aab
commit 03556e4d0d
2 changed files with 255 additions and 0 deletions

View File

@ -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;
}

View File

@ -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 */