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: 7af4cc3fa1
("[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>
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@ -838,11 +838,16 @@ nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
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}
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static int
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nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e, int diff)
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nfqnl_mangle(void *data, unsigned int data_len, struct nf_queue_entry *e, int diff)
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{
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struct sk_buff *nskb;
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if (diff < 0) {
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unsigned int min_len = skb_transport_offset(e->skb);
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if (data_len < min_len)
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return -EINVAL;
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if (pskb_trim(e->skb, data_len))
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return -ENOMEM;
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} else if (diff > 0) {
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