linux-kernel - [PATCH net 1/2] tap: add missing verification for short frame

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240724170452.16837-2-dongli.zhang@oracle.com>
Date: Wed, 24 Jul 2024 10:04:51 -0700
From: Dongli Zhang <dongli.zhang@...cle.com>
To: netdev@...r.kernel.org
Cc: willemdebruijn.kernel@...il.com, jasowang@...hat.com, davem@...emloft.net,
        edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
        ast@...nel.org, daniel@...earbox.net, hawk@...nel.org,
        john.fastabend@...il.com, linux-kernel@...r.kernel.org,
        bpf@...r.kernel.org, si-wei.liu@...cle.com
Subject: [PATCH net 1/2] tap: add missing verification for short frame

From: Si-Wei Liu <si-wei.liu@...cle.com>

The cited commit missed to check against the validity of the frame length
in the tap_get_user_xdp() path, which could cause a corrupted skb to be
sent downstack. Even before the skb is transmitted, the
tap_get_user_xdp()-->skb_set_network_header() may assume the size is more
than ETH_HLEN. Once transmitted, this could either cause out-of-bound
access beyond the actual length, or confuse the underlayer with incorrect
or inconsistent header length in the skb metadata.

In the alternative path, tap_get_user() already prohibits short frame which
has the length less than Ethernet header size from being transmitted.

This is to drop any frame shorter than the Ethernet header size just like
how tap_get_user() does.

CVE: CVE-2024-41090
Link: https://lore.kernel.org/netdev/1717026141-25716-1-git-send-email-si-wei.liu@oracle.com/
Fixes: 0efac27791ee ("tap: accept an array of XDP buffs through sendmsg()")
Cc: stable@...r.kernel.org
Signed-off-by: Si-Wei Liu <si-wei.liu@...cle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@...cle.com>
Reviewed-by: Willem de Bruijn <willemb@...gle.com>
Reviewed-by: Paolo Abeni <pabeni@...hat.com>
Reviewed-by: Jason Wang <jasowang@...hat.com>
---
 drivers/net/tap.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index bfdd3875fe86..77574f7a3bd4 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -1177,6 +1177,11 @@ static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp)
 	struct sk_buff *skb;
 	int err, depth;

+	if (unlikely(xdp->data_end - xdp->data < ETH_HLEN)) {
+		err = -EINVAL;
+		goto err;
+	}
+
 	if (q->flags & IFF_VNET_HDR)
 		vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);

-- 
2.34.1