On Sun, 2017-04-02 at 19:52 +0300, Denys Fedoryshchenko wrote:
> On 2017-04-02 15:32, Eric Dumazet wrote:
> > On Sun, 2017-04-02 at 15:25 +0300, Denys Fedoryshchenko wrote:
> >> > */
> >> I will add also WARN_ON_ONCE(tcp_hdrlen >= 15 * 4) before, for
> >> curiosity, if this condition are triggered. Is it fine like that?
> >
> > Sure.
>
> It didnt triggered WARN_ON, and with both patches here is one more
> KASAN.
> What i noticed also after this KASAN, there is many others start to
> trigger in TCPMSS and locking up server by flood.
> There is heavy netlink activity, it is pppoe server with lot of shapers.
> I noticed there left sfq by mistake, usually i am removing it, because
> it may trigger kernel panic too (and hard to trace reason).
> I will try with pfifo instead, after 6 hours.
>
> Here is full log with others: https://nuclearcat.com/kasan.txt
>
Could that be that netfilter does not abort earlier if TCP header is
completely wrong ?
diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c
index
27241a767f17b4b27d24095a31e5e9a2d3e29ce4..dd64bff38ba8074e6feb2e6e305eacb30ce4c2da
100644
--- a/net/netfilter/xt_TCPMSS.c
+++ b/net/netfilter/xt_TCPMSS.c
@@ -104,7 +104,7 @@ tcpmss_mangle_packet(struct sk_buff *skb,
tcph = (struct tcphdr *)(skb_network_header(skb) + tcphoff);
tcp_hdrlen = tcph->doff * 4;
- if (len < tcp_hdrlen)
+ if (len < tcp_hdrlen || tcp_hdrlen < sizeof(struct tcphdr))
return -1;
if (info->mss == XT_TCPMSS_CLAMP_PMTU) {
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
