Re: [PATCH] sctp: verify length provided in heartbeat information parameter

[Vlad Yasevich <vyasevich@gmail.com>]

On 11/30/2012 07:16 AM, Thomas Graf wrote:
> If the variable parameter length provided in the mandatory
> heartbeat information parameter exceeds the calculated payload
> length the packet has been corrupted. Reply with a parameter
> length protocol violation message.
>
> Signed-off-by: Thomas Graf <tgraf@suug.ch>

Acked-by: Vlad Yasevich <vyasevich@gmail.com>

-vlad

> ---
>   net/sctp/sm_statefuns.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
> index b6adef8..e92079d 100644
> --- a/net/sctp/sm_statefuns.c
> +++ b/net/sctp/sm_statefuns.c
> @@ -1055,6 +1055,7 @@ sctp_disposition_t sctp_sf_beat_8_3(struct net *net,
>   				    void *arg,
>   				    sctp_cmd_seq_t *commands)
>   {
> +	sctp_paramhdr_t *param_hdr;
>   	struct sctp_chunk *chunk = arg;
>   	struct sctp_chunk *reply;
>   	size_t paylen = 0;
> @@ -1072,12 +1073,17 @@ sctp_disposition_t sctp_sf_beat_8_3(struct net *net,
>   	 * Information field copied from the received HEARTBEAT chunk.
>   	 */
>   	chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
> +	param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr;
>   	paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
> +
> +	if (ntohs(param_hdr->length) > paylen)
> +		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
> +						  param_hdr, commands);
> +
>   	if (!pskb_pull(chunk->skb, paylen))
>   		goto nomem;
>
> -	reply = sctp_make_heartbeat_ack(asoc, chunk,
> -					chunk->subh.hb_hdr, paylen);
> +	reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
>   	if (!reply)
>   		goto nomem;
>
> --
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