From: Ignacy Gawędzki ignacy.gawedzki@green-communications.fr

mainline inclusion from mainline-v5.16-rc7 commit ebb966d3bdfed581ecccbb4a7432341baf7619b4 category: bugfix bugzilla: NA CVE: NA

--------------------------------

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 Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Yue Haibing yuehaibing@huawei.com Reviewed-by: Wei Yongjun weiyongjun1@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/netfilter/nfnetlink_log.c | 3 ++- net/netfilter/nfnetlink_queue.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c index 25298b3eb8546..17ca9a681d47b 100644 --- a/net/netfilter/nfnetlink_log.c +++ b/net/netfilter/nfnetlink_log.c @@ -509,7 +509,8 @@ __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 eb5a052d3b252..8955431f2ab26 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -566,7 +566,8 @@ 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;