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Message-Id: <20220809175513.816660088@linuxfoundation.org>
Date: Tue, 9 Aug 2022 20:00:14 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
Domingo Dirutigliano <pwnzer0tt1@...ton.me>,
Florian Westphal <fw@...len.de>,
Pablo Neira Ayuso <pablo@...filter.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 23/32] netfilter: nf_queue: do not allow packet truncation below transport header offset
From: Florian Westphal <fw@...len.de>
[ 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@...ton.me>
Signed-off-by: Florian Westphal <fw@...len.de>
Reviewed-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
net/netfilter/nfnetlink_queue.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index a5aff2834bd6..cd496b074a71 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -850,11 +850,16 @@ 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) {
--
2.35.1
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