Commit 24a997ac authored by Si-Wei Liu's avatar Si-Wei Liu Committed by Liu Jian
Browse files

tap: add missing verification for short frame 

stable inclusion
from stable-v6.6.43
commit aa6a5704cab861c9b2ae9f475076e1881e87f5aa
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAG8ZG
CVE: CVE-2024-41090

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=aa6a5704cab861c9b2ae9f475076e1881e87f5aa

---------------------------

commit ed7f2afdd0e043a397677e597ced0830b83ba0b3 upstream.

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: 0efac277 ("tap: accept an array of XDP buffs through sendmsg()")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarSi-Wei Liu <si-wei.liu@oracle.com>
Signed-off-by: default avatarDongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Reviewed-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarJason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20240724170452.16837-2-dongli.zhang@oracle.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarLiu Jian <liujian56@huawei.com>
parent 4ad15c7f

drivers/net/tap.c

+5 −0
Original line number Diff line number Diff line
@@ -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);