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authorFlorian Westphal <fw@strlen.de>2023-01-26 02:35:21 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2023-01-31 14:02:48 +0100
commitbd0e06f0def75ba26572a94e5350324474a55562 (patch)
treef32e0ac561c3280b84dbe52581fac886fb815fe8
parent2b272bb558f1d3a5aa95ed8a82253786fd1a48ba (diff)
Revert "netfilter: conntrack: fix bug in for_each_sctp_chunk"
There is no bug. If sch->length == 0, this would result in an infinite loop, but first caller, do_basic_checks(), errors out in this case. After this change, packets with bogus zero-length chunks are no longer detected as invalid, so revert & add comment wrt. 0 length check. Fixes: 98ee00774525 ("netfilter: conntrack: fix bug in for_each_sctp_chunk") Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
-rw-r--r--net/netfilter/nf_conntrack_proto_sctp.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c
index 945dd40e7077..011d414038ea 100644
--- a/net/netfilter/nf_conntrack_proto_sctp.c
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -142,10 +142,11 @@ static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
}
#endif
+/* do_basic_checks ensures sch->length > 0, do not use before */
#define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) \
for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0; \
- ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))) && \
- (sch)->length; \
+ (offset) < (skb)->len && \
+ ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))); \
(offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
/* Some validity checks to make sure the chunks are fine */