From 985970fd0118576d9853d1d1a9c4309ae4d248bb Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 22 Mar 2016 18:02:52 +0100 Subject: [PATCH] netfilter: x_tables: fix unconditional helper commit 54d83fc74aa9ec72794373cb47432c5f7fb1a309 upstream. Ben Hawkes says: In the mark_source_chains function (net/ipv4/netfilter/ip_tables.c) it is possible for a user-supplied ipt_entry structure to have a large next_offset field. This field is not bounds checked prior to writing a counter value at the supplied offset. Problem is that mark_source_chains should not have been called -- the rule doesn't have a next entry, so its supposed to return an absolute verdict of either ACCEPT or DROP. However, the function conditional() doesn't work as the name implies. It only checks that the rule is using wildcard address matching. However, an unconditional rule must also not be using any matches (no -m args). The underflow validator only checked the addresses, therefore passing the 'unconditional absolute verdict' test, while mark_source_chains also tested for presence of matches, and thus proceeeded to the next (not-existent) rule. Unify this so that all the callers have same idea of 'unconditional rule'. Reported-by: Ben Hawkes Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Ben Hutchings --- Reading git-format-patch failed