From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org,
pabeni@redhat.com, edumazet@google.com
Subject: [PATCH net 3/3] netfilter: nft_payload: incorrect arithmetics when fetching VLAN header bits
Date: Fri, 13 Jan 2023 17:41:06 +0100 [thread overview]
Message-ID: <20230113164106.311491-4-pablo@netfilter.org> (raw)
In-Reply-To: <20230113164106.311491-1-pablo@netfilter.org>
If the offset + length goes over the ethernet + vlan header, then the
length is adjusted to copy the bytes that are within the boundaries of
the vlan_ethhdr scratchpad area. The remaining bytes beyond ethernet +
vlan header are copied directly from the skbuff data area.
Fix incorrect arithmetic operator: subtract, not add, the size of the
vlan header in case of double-tagged packets to adjust the length
accordingly to address CVE-2023-0179.
Reported-by: Davide Ornaghi <d.ornaghi97@gmail.com>
Fixes: f6ae9f120dad ("netfilter: nft_payload: add C-VLAN support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nft_payload.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index 17b418a5a593..3a3c7746e88f 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -63,7 +63,7 @@ nft_payload_copy_vlan(u32 *d, const struct sk_buff *skb, u8 offset, u8 len)
return false;
if (offset + len > VLAN_ETH_HLEN + vlan_hlen)
- ethlen -= offset + len - VLAN_ETH_HLEN + vlan_hlen;
+ ethlen -= offset + len - VLAN_ETH_HLEN - vlan_hlen;
memcpy(dst_u8, vlanh + offset - vlan_hlen, ethlen);
--
2.30.2
next prev parent reply other threads:[~2023-01-13 16:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-13 16:41 [PATCH net 0/3] Netfilter fixes for net Pablo Neira Ayuso
2023-01-13 16:41 ` [PATCH net 1/3] selftests: netfilter: fix transaction test script timeout handling Pablo Neira Ayuso
2023-01-13 16:41 ` [PATCH net 2/3] netfilter: ipset: Fix overflow before widen in the bitmap_ip_create() function Pablo Neira Ayuso
2023-01-13 16:41 ` Pablo Neira Ayuso [this message]
2023-01-18 3:03 ` [PATCH net 0/3] Netfilter fixes for net Jakub Kicinski
-- strict thread matches above, loose matches on Subject: below --
2023-01-11 21:22 Pablo Neira Ayuso
2023-01-11 21:22 ` [PATCH net 3/3] netfilter: nft_payload: incorrect arithmetics when fetching VLAN header bits Pablo Neira Ayuso
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