From 98ee0077452527f971567db01386de3c3d97ce13 Mon Sep 17 00:00:00 2001 From: Sriram Yagnaraman Date: Tue, 24 Jan 2023 02:47:19 +0100 Subject: netfilter: conntrack: fix bug in for_each_sctp_chunk skb_header_pointer() will return NULL if offset + sizeof(_sch) exceeds skb->len, so this offset < skb->len test is redundant. if sch->length == 0, this will end up in an infinite loop, add a check for sch->length > 0 Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.") Suggested-by: Florian Westphal Signed-off-by: Sriram Yagnaraman Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_proto_sctp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net') diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c index 2b2c549ba678..c561c1213704 100644 --- a/net/netfilter/nf_conntrack_proto_sctp.c +++ b/net/netfilter/nf_conntrack_proto_sctp.c @@ -160,8 +160,8 @@ static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct) #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) \ for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0; \ - (offset) < (skb)->len && \ - ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))); \ + ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))) && \ + (sch)->length; \ (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++) /* Some validity checks to make sure the chunks are fine */ -- cgit v1.2.3