| Message ID | 20210912212433.45389-1-jeremy@azazel.net |
|---|---|
| State | Accepted |
| Delegated to: | Pablo Neira |
| Headers | show |
| Series | [nf] netfilter: ip6_tables: zero-initialize fragment offset | expand |
Jeremy Sowden <jeremy@azazel.net> wrote: > 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. Fixes: f7108a20dee44 ("netfilter: xtables: move extension arguments into compound structure (1/6)" Reviewed-by: Florian Westphal <fw@strlen.de>
On 2021-09-13, at 01:39:00 +0200, Florian Westphal wrote: > Jeremy Sowden <jeremy@azazel.net> wrote: > > 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. > > Fixes: f7108a20dee44 ("netfilter: xtables: move extension arguments into compound structure (1/6)" > Reviewed-by: Florian Westphal <fw@strlen.de> Thanks, Florian. J.
On Sun, Sep 12, 2021 at 10:24:33PM +0100, Jeremy Sowden wrote: > 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. Applied, thanks.
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index de2cf3943b91..a579ea14a69b 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;
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> --- net/ipv6/netfilter/ip6_tables.c | 1 + 1 file changed, 1 insertion(+)