mac802154: add llsec decryption 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 17:46:39 +02:00 committed by David S. Miller
parent 03556e4d0d
commit 4c14a2fb5d
2 changed files with 248 additions and 0 deletions

View File

@ -18,6 +18,7 @@
#include <linux/bug.h>
#include <linux/completion.h>
#include <net/ieee802154.h>
#include <crypto/algapi.h>
#include "mac802154.h"
#include "llsec.h"
@ -780,3 +781,249 @@ int mac802154_llsec_encrypt(struct mac802154_llsec *sec, struct sk_buff *skb)
rcu_read_unlock();
return rc;
}
static struct mac802154_llsec_device*
llsec_lookup_dev(struct mac802154_llsec *sec,
const struct ieee802154_addr *addr)
{
struct ieee802154_addr devaddr = *addr;
struct mac802154_llsec_device *dev = NULL;
if (devaddr.mode == IEEE802154_ADDR_NONE &&
llsec_recover_addr(sec, &devaddr) < 0)
return NULL;
if (devaddr.mode == IEEE802154_ADDR_SHORT) {
u32 key = llsec_dev_hash_short(devaddr.short_addr,
devaddr.pan_id);
hash_for_each_possible_rcu(sec->devices_short, dev,
bucket_s, key) {
if (dev->dev.pan_id == devaddr.pan_id &&
dev->dev.short_addr == devaddr.short_addr)
return dev;
}
} else {
u64 key = llsec_dev_hash_long(devaddr.extended_addr);
hash_for_each_possible_rcu(sec->devices_hw, dev,
bucket_hw, key) {
if (dev->dev.hwaddr == devaddr.extended_addr)
return dev;
}
}
return NULL;
}
static int
llsec_lookup_seclevel(const struct mac802154_llsec *sec,
u8 frame_type, u8 cmd_frame_id,
struct ieee802154_llsec_seclevel *rlevel)
{
struct ieee802154_llsec_seclevel *level;
list_for_each_entry_rcu(level, &sec->table.security_levels, list) {
if (level->frame_type == frame_type &&
(frame_type != IEEE802154_FC_TYPE_MAC_CMD ||
level->cmd_frame_id == cmd_frame_id)) {
*rlevel = *level;
return 0;
}
}
return -EINVAL;
}
static int
llsec_do_decrypt_unauth(struct sk_buff *skb, const struct mac802154_llsec *sec,
const struct ieee802154_hdr *hdr,
struct mac802154_llsec_key *key, __le64 dev_addr)
{
u8 iv[16];
unsigned char *data;
int datalen;
struct scatterlist src;
struct blkcipher_desc req = {
.tfm = key->tfm0,
.info = iv,
.flags = 0,
};
llsec_geniv(iv, dev_addr, &hdr->sec);
data = skb_mac_header(skb) + skb->mac_len;
datalen = skb_tail_pointer(skb) - data;
sg_init_one(&src, data, datalen);
return crypto_blkcipher_decrypt_iv(&req, &src, &src, datalen);
}
static int
llsec_do_decrypt_auth(struct sk_buff *skb, const struct mac802154_llsec *sec,
const struct ieee802154_hdr *hdr,
struct mac802154_llsec_key *key, __le64 dev_addr)
{
u8 iv[16];
unsigned char *data;
int authlen, datalen, assoclen, rc;
struct scatterlist src, assoc[2];
struct aead_request *req;
authlen = ieee802154_sechdr_authtag_len(&hdr->sec);
llsec_geniv(iv, dev_addr, &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 - authlen);
assoclen += datalen - authlen;
data += datalen - authlen;
datalen = authlen;
}
sg_init_one(&src, data, datalen);
aead_request_set_callback(req, 0, NULL, NULL);
aead_request_set_assoc(req, assoc, assoclen);
aead_request_set_crypt(req, &src, &src, datalen, iv);
rc = crypto_aead_decrypt(req);
kfree(req);
skb_trim(skb, skb->len - authlen);
return rc;
}
static int
llsec_do_decrypt(struct sk_buff *skb, const struct mac802154_llsec *sec,
const struct ieee802154_hdr *hdr,
struct mac802154_llsec_key *key, __le64 dev_addr)
{
if (hdr->sec.level == IEEE802154_SCF_SECLEVEL_ENC)
return llsec_do_decrypt_unauth(skb, sec, hdr, key, dev_addr);
else
return llsec_do_decrypt_auth(skb, sec, hdr, key, dev_addr);
}
static int
llsec_update_devkey_info(struct mac802154_llsec_device *dev,
const struct ieee802154_llsec_key_id *in_key,
u32 frame_counter)
{
struct mac802154_llsec_device_key *devkey = NULL;
if (dev->dev.key_mode == IEEE802154_LLSEC_DEVKEY_RESTRICT) {
devkey = llsec_devkey_find(dev, in_key);
if (!devkey)
return -ENOENT;
}
spin_lock_bh(&dev->lock);
if ((!devkey && frame_counter < dev->dev.frame_counter) ||
(devkey && frame_counter < devkey->devkey.frame_counter)) {
spin_unlock_bh(&dev->lock);
return -EINVAL;
}
if (devkey)
devkey->devkey.frame_counter = frame_counter + 1;
else
dev->dev.frame_counter = frame_counter + 1;
spin_unlock_bh(&dev->lock);
return 0;
}
int mac802154_llsec_decrypt(struct mac802154_llsec *sec, struct sk_buff *skb)
{
struct ieee802154_hdr hdr;
struct mac802154_llsec_key *key;
struct ieee802154_llsec_key_id key_id;
struct mac802154_llsec_device *dev;
struct ieee802154_llsec_seclevel seclevel;
int err;
__le64 dev_addr;
u32 frame_ctr;
if (ieee802154_hdr_peek(skb, &hdr) < 0)
return -EINVAL;
if (!hdr.fc.security_enabled)
return 0;
if (hdr.fc.version == 0)
return -EINVAL;
read_lock_bh(&sec->lock);
if (!sec->params.enabled) {
read_unlock_bh(&sec->lock);
return -EINVAL;
}
read_unlock_bh(&sec->lock);
rcu_read_lock();
key = llsec_lookup_key(sec, &hdr, &hdr.source, &key_id);
if (!key) {
err = -ENOKEY;
goto fail;
}
dev = llsec_lookup_dev(sec, &hdr.source);
if (!dev) {
err = -EINVAL;
goto fail_dev;
}
if (llsec_lookup_seclevel(sec, hdr.fc.type, 0, &seclevel) < 0) {
err = -EINVAL;
goto fail_dev;
}
if (!(seclevel.sec_levels & BIT(hdr.sec.level)) &&
(hdr.sec.level == 0 && seclevel.device_override &&
!dev->dev.seclevel_exempt)) {
err = -EINVAL;
goto fail_dev;
}
frame_ctr = le32_to_cpu(hdr.sec.frame_counter);
if (frame_ctr == 0xffffffff) {
err = -EOVERFLOW;
goto fail_dev;
}
err = llsec_update_devkey_info(dev, &key_id, frame_ctr);
if (err)
goto fail_dev;
dev_addr = dev->dev.hwaddr;
rcu_read_unlock();
err = llsec_do_decrypt(skb, sec, &hdr, key, dev_addr);
llsec_key_put(key);
return err;
fail_dev:
llsec_key_put(key);
fail:
rcu_read_unlock();
return err;
}

View File

@ -103,5 +103,6 @@ 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);
int mac802154_llsec_decrypt(struct mac802154_llsec *sec, struct sk_buff *skb);
#endif /* MAC802154_LLSEC_H */