4.19-stable review patch. If anyone has any objections, please let me know.
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From: Pablo Neira Ayuso pablo@netfilter.org
[ Upstream commit d5953d680f7e96208c29ce4139a0e38de87a57fe ]
If access to offset + length is larger than the skbuff length, then skb_checksum() triggers BUG_ON().
skb_checksum() internally subtracts the length parameter while iterating over skbuff, BUG_ON(len) at the end of it checks that the expected length to be included in the checksum calculation is fully consumed.
Fixes: 7ec3f7b47b8d ("netfilter: nft_payload: add packet mangling support") Reported-by: Slavin Liu slavin-ayu@qq.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nft_payload.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c index 0ef51c81ec94c..128195a7ea5ed 100644 --- a/net/netfilter/nft_payload.c +++ b/net/netfilter/nft_payload.c @@ -306,6 +306,9 @@ static void nft_payload_set_eval(const struct nft_expr *expr, if ((priv->csum_type == NFT_PAYLOAD_CSUM_INET || priv->csum_flags) && (priv->base != NFT_PAYLOAD_TRANSPORT_HEADER || skb->ip_summed != CHECKSUM_PARTIAL)) { + if (offset + priv->len > skb->len) + goto err; + fsum = skb_checksum(skb, offset, priv->len, 0); tsum = csum_partial(src, priv->len, 0);