From: Marcelo Ricardo Leitner Date: Mon, 28 Jun 2021 19:13:42 +0000 (-0300) Subject: sctp: add size validation when walking chunks X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=50619dbf8db77e98d821d615af4f634d08e22698;p=linux.git sctp: add size validation when walking chunks The first chunk in a packet is ensured to be present at the beginning of sctp_rcv(), as a packet needs to have at least 1 chunk. But the second one, may not be completely available and ch->length can be over uninitialized memory. Fix here is by only trying to walk on the next chunk if there is enough to hold at least the header, and then proceed with the ch->length validation that is already there. Reported-by: Ilja Van Sprundel Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- diff --git a/net/sctp/input.c b/net/sctp/input.c index 8924e2e142c82..f72bff93745c4 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -1247,7 +1247,7 @@ static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net, ch = (struct sctp_chunkhdr *)ch_end; chunk_num++; - } while (ch_end < skb_tail_pointer(skb)); + } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb)); return asoc; }