From: Jordy Zomer <jordy@pwning.systems> stable inclusion from stable-v5.10.84 commit 4d5968ea06fbfc7f6bb88dee7ce459f4755cebb5 bugzilla: 186030 https://gitee.com/openeuler/kernel/issues/I4QV2F Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ 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 <jordy@pwning.systems> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- net/ipv6/esp6.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index 8d001f665fb1..7f2ffc7b1f75 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; -- 2.20.1