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).
BUG=b/241534002
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2022-36946 in the Linux kernel.
Fixes: 7af4cc3fa158 ("[NETFILTER]: Add "nfnetlink_queue" netfilter queue handler over nfnetlink")
Reported-by: Domingo Dirutigliano <pwnzer0tt1@proton.me>
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
cos-patch: security-high
Change-Id: I55fc69adfdcfccb5dab8a2abce66dcea767c595e
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/36795
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 7d3ab08..581bd13 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -846,11 +846,16 @@
}
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) {
