Re: [PATCH bluetooth-next] mac802154: fix llsec authentication without encryption BUG

[Stefan Schmidt <stefan@osg.samsung.com>]

Hello.

On 18/06/15 17:55, Simon Vincent wrote:
>   802.15.4 security levels 1,2,3 provide data authenticity but
>   no encryption. Currently the llsec implementation hits a BUG() if these modes
>   are used. This is due to the scatterlist length being set to 0 when
>   encryption is not used. This patch fixes this issue.
I have not reviewed the patch yet, but adding a comment here that Phoebe 
pointed out where the problem is might be nice for credits.

regards
Stefan Schmidt

> Signed-off-by: Simon Vincent <simon.vincent@xsilon.com>
> ---
>   net/mac802154/llsec.c | 22 +++++++++++-----------
>   1 file changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/net/mac802154/llsec.c b/net/mac802154/llsec.c
> index 5b2be12..f8081f0 100644
> --- a/net/mac802154/llsec.c
> +++ b/net/mac802154/llsec.c
> @@ -648,7 +648,8 @@ llsec_do_encrypt_auth(struct sk_buff *skb, const struct mac802154_llsec *sec,
>   {
>   	u8 iv[16];
>   	unsigned char *data;
> -	int authlen, assoclen, datalen, rc;
> +	int authlen, datalen, rc;
> +	int assoclen = 0;
>   	struct scatterlist src, assoc[2], dst[2];
>   	struct aead_request *req;
>   
> @@ -659,26 +660,25 @@ llsec_do_encrypt_auth(struct sk_buff *skb, const struct mac802154_llsec *sec,
>   	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);
> +		sg_init_table(assoc, 1);
> +		sg_init_table(dst, 2);
> +		sg_set_buf(&dst[0], data, datalen);
> +		sg_set_buf(&dst[1], skb_put(skb, authlen), authlen);
> +		sg_init_one(&src, data, datalen);
>   	} else {
> +		sg_init_table(assoc, 2);
>   		sg_set_buf(&assoc[1], data, datalen);
>   		assoclen += datalen;
>   		datalen = 0;
> +		sg_init_one(dst, skb_put(skb, authlen), authlen);
>   	}
>   
> -	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);
> +	sg_set_buf(&assoc[0], skb_mac_header(skb), skb->mac_len);
> +	assoclen += skb->mac_len;
>   
>   	aead_request_set_callback(req, 0, NULL, NULL);
>   	aead_request_set_assoc(req, assoc, assoclen);