This is a note to let you know that I've just added the patch titled netfilter: nf_queue: do not allow packet truncation below transport header offset to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: netfilter-nf_queue-do-not-allow-packet-truncation-be.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit bab893233260229ee8d558c0e53ebf015aab17cb Author: Florian Westphal <fw@xxxxxxxxx> Date: Tue Jul 26 12:42:06 2022 +0200 netfilter: nf_queue: do not allow packet truncation below transport header offset [ Upstream commit 99a63d36cb3ed5ca3aa6fcb64cffbeaf3b0fb164 ] Domingo Dirutigliano and Nicola Guerrera report kernel panic when sending nf_queue verdict with 1-byte nfta_payload attribute. The IP/IPv6 stack pulls the IP(v6) header from the packet after the input hook. If user truncates the packet below the header size, this skb_pull() will result in a malformed skb (skb->len < 0). Fixes: 7af4cc3fa158 ("[NETFILTER]: Add "nfnetlink_queue" netfilter queue handler over nfnetlink") Reported-by: Domingo Dirutigliano <pwnzer0tt1@xxxxxxxxx> Signed-off-by: Florian Westphal <fw@xxxxxxxxx> Reviewed-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index ba74bb2d6341..369f1634afe9 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -827,11 +827,16 @@ nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum) } static int -nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e, int diff) +nfqnl_mangle(void *data, unsigned int data_len, struct nf_queue_entry *e, int diff) { struct sk_buff *nskb; if (diff < 0) { + unsigned int min_len = skb_transport_offset(e->skb); + + if (data_len < min_len) + return -EINVAL; + if (pskb_trim(e->skb, data_len)) return -ENOMEM; } else if (diff > 0) {