| Message ID | 20211117190648.2732560-1-jordy@pwning.systems (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 5f9c55c8066bcd93ac25234a02585701fe2e31df |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2] ipv6: check return value of ipv6_skip_exthdr | expand |
Hello: This patch was applied to netdev/net.git (master) by David S. Miller <davem@davemloft.net>: On Wed, 17 Nov 2021 20:06:48 +0100 you wrote: > 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 > > [...] Here is the summary with links: - [v2] ipv6: check return value of ipv6_skip_exthdr https://git.kernel.org/netdev/net/c/5f9c55c8066b You are awesome, thank you!
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index ed2f061b8768..f0bac6f7ab6b 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;
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> --- net/ipv6/esp6.c | 6 ++++++ 1 file changed, 6 insertions(+)