[PATCH 5.10 05/22] netfilter: ip6_tables: zero-initialize fragment offset

Greg Kroah-Hartman
2021-10-14T15:03:09Z

From: Jeremy Sowden <jeremy@azazel.net>

[ Upstream commit 310e2d43c3ad429c1fba4b175806cf1f55ed73a6 ]

ip6tables only sets the `IP6T_F_PROTO` flag on a rule if a protocol is
specified (`-p tcp`, for example). However, if the flag is not set,
`ip6_packet_match` doesn't call `ipv6_find_hdr` for the skb, in which
case the fragment offset is left uninitialized and a garbage value is
passed to each matcher.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv6/netfilter/ip6_tables.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index eb2b5404806c..d36168baf677 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -273,6 +273,7 @@ ip6t_do_table(struct sk_buff *skb,
* things we don't know, ie. tcp syn flag or ports). If the
* rule is also a fragment-specific rule, non-fragments won't
* match it. */
+ acpar.fragoff = 0;
acpar.hotdrop = false;
acpar.state = state;

--
2.33.0