From 634ef8cf4e51841a1f7d7bd5771335b4e1960690 Mon Sep 17 00:00:00 2001 From: Jordy Zomer Date: Wed, 17 Nov 2021 20:06:48 +0100 Subject: [PATCH] ipv6: check return value of ipv6_skip_exthdr [ Upstream commit 5f9c55c8066bcd93ac25234a02585701fe2e31df ] The offset value is used in pointer math on skb->data. Since ipv6_skip_exthdr may return -1 the pointer to uh and th may not point to the actual udp and tcp headers and potentially overwrite other stuff. This is why I think this should be checked. EDIT: added {}'s, thanks Kees Signed-off-by: Jordy Zomer Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv6/esp6.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index ed2f061..f0bac6f 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -808,6 +808,12 @@ int esp6_input_done2(struct sk_buff *skb, int err) struct tcphdr *th; offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); + + if (offset < 0) { + err = -EINVAL; + goto out; + } + uh = (void *)(skb->data + offset); th = (void *)(skb->data + offset); hdr_len += offset; -- 2.7.4