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
David S. Miller
parent
03556e4d0d
commit
4c14a2fb5d
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@ -18,6 +18,7 @@
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#include <linux/bug.h>
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#include <linux/completion.h>
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#include <net/ieee802154.h>
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#include <crypto/algapi.h>
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#include "mac802154.h"
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#include "llsec.h"
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@ -780,3 +781,249 @@ fail:
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rcu_read_unlock();
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return rc;
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}
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static struct mac802154_llsec_device*
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llsec_lookup_dev(struct mac802154_llsec *sec,
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const struct ieee802154_addr *addr)
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{
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struct ieee802154_addr devaddr = *addr;
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struct mac802154_llsec_device *dev = NULL;
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if (devaddr.mode == IEEE802154_ADDR_NONE &&
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llsec_recover_addr(sec, &devaddr) < 0)
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return NULL;
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if (devaddr.mode == IEEE802154_ADDR_SHORT) {
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u32 key = llsec_dev_hash_short(devaddr.short_addr,
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devaddr.pan_id);
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hash_for_each_possible_rcu(sec->devices_short, dev,
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bucket_s, key) {
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if (dev->dev.pan_id == devaddr.pan_id &&
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dev->dev.short_addr == devaddr.short_addr)
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return dev;
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}
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} else {
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u64 key = llsec_dev_hash_long(devaddr.extended_addr);
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hash_for_each_possible_rcu(sec->devices_hw, dev,
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bucket_hw, key) {
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if (dev->dev.hwaddr == devaddr.extended_addr)
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return dev;
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}
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}
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return NULL;
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}
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static int
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llsec_lookup_seclevel(const struct mac802154_llsec *sec,
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u8 frame_type, u8 cmd_frame_id,
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struct ieee802154_llsec_seclevel *rlevel)
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{
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struct ieee802154_llsec_seclevel *level;
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list_for_each_entry_rcu(level, &sec->table.security_levels, list) {
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if (level->frame_type == frame_type &&
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(frame_type != IEEE802154_FC_TYPE_MAC_CMD ||
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level->cmd_frame_id == cmd_frame_id)) {
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*rlevel = *level;
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return 0;
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}
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}
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return -EINVAL;
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}
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static int
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llsec_do_decrypt_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, __le64 dev_addr)
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{
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u8 iv[16];
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unsigned char *data;
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int datalen;
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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, dev_addr, &hdr->sec);
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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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sg_init_one(&src, data, datalen);
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return crypto_blkcipher_decrypt_iv(&req, &src, &src, datalen);
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}
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static int
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llsec_do_decrypt_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, __le64 dev_addr)
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{
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u8 iv[16];
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unsigned char *data;
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int authlen, datalen, assoclen, rc;
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struct scatterlist src, assoc[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, dev_addr, &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 - authlen);
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assoclen += datalen - authlen;
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data += datalen - authlen;
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datalen = authlen;
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}
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sg_init_one(&src, data, datalen);
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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, &src, datalen, iv);
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rc = crypto_aead_decrypt(req);
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kfree(req);
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skb_trim(skb, skb->len - authlen);
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return rc;
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}
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static int
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llsec_do_decrypt(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, __le64 dev_addr)
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{
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if (hdr->sec.level == IEEE802154_SCF_SECLEVEL_ENC)
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return llsec_do_decrypt_unauth(skb, sec, hdr, key, dev_addr);
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else
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return llsec_do_decrypt_auth(skb, sec, hdr, key, dev_addr);
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}
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static int
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llsec_update_devkey_info(struct mac802154_llsec_device *dev,
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const struct ieee802154_llsec_key_id *in_key,
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u32 frame_counter)
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{
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struct mac802154_llsec_device_key *devkey = NULL;
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if (dev->dev.key_mode == IEEE802154_LLSEC_DEVKEY_RESTRICT) {
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devkey = llsec_devkey_find(dev, in_key);
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if (!devkey)
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return -ENOENT;
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}
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spin_lock_bh(&dev->lock);
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if ((!devkey && frame_counter < dev->dev.frame_counter) ||
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(devkey && frame_counter < devkey->devkey.frame_counter)) {
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spin_unlock_bh(&dev->lock);
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return -EINVAL;
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}
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if (devkey)
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devkey->devkey.frame_counter = frame_counter + 1;
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else
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dev->dev.frame_counter = frame_counter + 1;
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spin_unlock_bh(&dev->lock);
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return 0;
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}
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int mac802154_llsec_decrypt(struct mac802154_llsec *sec, struct sk_buff *skb)
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{
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struct ieee802154_hdr hdr;
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struct mac802154_llsec_key *key;
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struct ieee802154_llsec_key_id key_id;
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struct mac802154_llsec_device *dev;
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struct ieee802154_llsec_seclevel seclevel;
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int err;
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__le64 dev_addr;
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u32 frame_ctr;
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if (ieee802154_hdr_peek(skb, &hdr) < 0)
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return -EINVAL;
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if (!hdr.fc.security_enabled)
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return 0;
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if (hdr.fc.version == 0)
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return -EINVAL;
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read_lock_bh(&sec->lock);
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if (!sec->params.enabled) {
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read_unlock_bh(&sec->lock);
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return -EINVAL;
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}
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read_unlock_bh(&sec->lock);
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rcu_read_lock();
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key = llsec_lookup_key(sec, &hdr, &hdr.source, &key_id);
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if (!key) {
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err = -ENOKEY;
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goto fail;
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}
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dev = llsec_lookup_dev(sec, &hdr.source);
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if (!dev) {
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err = -EINVAL;
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goto fail_dev;
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}
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if (llsec_lookup_seclevel(sec, hdr.fc.type, 0, &seclevel) < 0) {
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err = -EINVAL;
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goto fail_dev;
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}
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if (!(seclevel.sec_levels & BIT(hdr.sec.level)) &&
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(hdr.sec.level == 0 && seclevel.device_override &&
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!dev->dev.seclevel_exempt)) {
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err = -EINVAL;
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goto fail_dev;
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}
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frame_ctr = le32_to_cpu(hdr.sec.frame_counter);
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if (frame_ctr == 0xffffffff) {
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err = -EOVERFLOW;
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goto fail_dev;
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}
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err = llsec_update_devkey_info(dev, &key_id, frame_ctr);
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if (err)
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goto fail_dev;
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dev_addr = dev->dev.hwaddr;
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rcu_read_unlock();
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err = llsec_do_decrypt(skb, sec, &hdr, key, dev_addr);
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llsec_key_put(key);
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return err;
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fail_dev:
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llsec_key_put(key);
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fail:
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rcu_read_unlock();
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return err;
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}
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@ -103,5 +103,6 @@ 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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int mac802154_llsec_decrypt(struct mac802154_llsec *sec, struct sk_buff *skb);
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#endif /* MAC802154_LLSEC_H */
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