path: root/net/netfilter
diff options
authorIgnacy Gawędzki <ignacy.gawedzki@green-communications.fr>2021-12-10 16:31:27 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2021-12-16 00:06:24 +0100
commitebb966d3bdfed581ecccbb4a7432341baf7619b4 (patch)
tree769b61302917f9342b3379a2376be2ebc93792e9 /net/netfilter
parentnetfilter: nf_tables: fix use-after-free in nft_set_catchall_destroy() (diff)
netfilter: fix regression in looped (broad|multi)cast's MAC handling
In commit 5648b5e1169f ("netfilter: nfnetlink_queue: fix OOB when mac header was cleared"), the test for non-empty MAC header introduced in commit 2c38de4c1f8da7 ("netfilter: fix looped (broad|multi)cast's MAC handling") has been replaced with a test for a set MAC header. This breaks the case when the MAC header has been reset (using skb_reset_mac_header), as is the case with looped-back multicast packets. As a result, the packets ending up in NFQUEUE get a bogus hwaddr interpreted from the first bytes of the IP header. This patch adds a test for a non-empty MAC header in addition to the test for a set MAC header. The same two tests are also implemented in nfnetlink_log.c, where the initial code of commit 2c38de4c1f8da7 ("netfilter: fix looped (broad|multi)cast's MAC handling") has not been touched, but where supposedly the same situation may happen. Fixes: 5648b5e1169f ("netfilter: nfnetlink_queue: fix OOB when mac header was cleared") Signed-off-by: Ignacy Gawędzki <ignacy.gawedzki@green-communications.fr> Reviewed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
2 files changed, 4 insertions, 2 deletions
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index 691ef4cffdd9..7f83f9697fc1 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -556,7 +556,8 @@ __build_packet_message(struct nfnl_log_net *log,
goto nla_put_failure;
if (indev && skb->dev &&
- skb->mac_header != skb->network_header) {
+ skb_mac_header_was_set(skb) &&
+ skb_mac_header_len(skb) != 0) {
struct nfulnl_msg_packet_hw phw;
int len;
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 5837e8efc9c2..f0b9e21a2452 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -560,7 +560,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
goto nla_put_failure;
if (indev && entskb->dev &&
- skb_mac_header_was_set(entskb)) {
+ skb_mac_header_was_set(entskb) &&
+ skb_mac_header_len(entskb) != 0) {
struct nfqnl_msg_packet_hw phw;
int len;