| From 28472faa9eb9cc244cef8a461722727873aba744 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 17 Nov 2021 20:06:48 +0100 |
| Subject: ipv6: check return value of ipv6_skip_exthdr |
| |
| From: Jordy Zomer <jordy@pwning.systems> |
| |
| [ 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> |
| --- |
| net/ipv6/esp6.c | 6 ++++++ |
| 1 file changed, 6 insertions(+) |
| |
| diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c |
| index 8d001f665fb15..7f2ffc7b1f75a 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; |
| -- |
| 2.33.0 |
| |
