[PATCH] sctp: verify length provided in heartbeat information parameter
From: Thomas Graf <tgraf@suug.ch>
Date: 2012-11-30 12:16:28
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> --- 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;