In nft's nft_exthdr_eval() routine we process IPv6 extension header through invoking ipv6_find_hdr(), but we call it with an uninitialized offset variable that contains some stack value. In ipv6_find_hdr() we then test if the value of offset != 0 and call skb_header_pointer() on that offset in order to map struct ipv6hdr into it. Fix it up by initializing offset to 0 as it was probably intended to be. Fixes: 96518518cc41 ("netfilter: add nftables") Signed-off-by: Daniel Borkmann <dborkman@xxxxxxxxxx> Cc: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx> --- net/netfilter/nft_exthdr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c index 8e0bb75..55c939f 100644 --- a/net/netfilter/nft_exthdr.c +++ b/net/netfilter/nft_exthdr.c @@ -31,7 +31,7 @@ static void nft_exthdr_eval(const struct nft_expr *expr, { struct nft_exthdr *priv = nft_expr_priv(expr); struct nft_data *dest = &data[priv->dreg]; - unsigned int offset; + unsigned int offset = 0; int err; err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL); -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html