diff options
| author | Florian Westphal <fw@strlen.de> | 2022-07-26 12:42:06 +0200 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2022-07-26 21:12:42 +0200 |
| commit | 99a63d36cb3ed5ca3aa6fcb64cffbeaf3b0fb164 (patch) | |
| tree | 3c552bf8a966f236cf0bfb778f4b3a945150b2cc /net | |
| parent | 9b134b1694ec8926926ba6b7b80884ea829245a0 (diff) | |
netfilter: nf_queue: do not allow packet truncation below transport header offset
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@proton.me>
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nfnetlink_queue.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index a364f8e5e698..87a9009d5234 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -843,11 +843,16 @@ 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) { |