From ed7f2afdd0e043a397677e597ced0830b83ba0b3 Mon Sep 17 00:00:00 2001 From: Si-Wei Liu Date: Wed, 24 Jul 2024 10:04:51 -0700 Subject: [PATCH 1/2] tap: add missing verification for short frame 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@vger.kernel.org Signed-off-by: Si-Wei Liu Signed-off-by: Dongli Zhang Reviewed-by: Willem de Bruijn Reviewed-by: Paolo Abeni Reviewed-by: Jason Wang Link: https://patch.msgid.link/20240724170452.16837-2-dongli.zhang@oracle.com Signed-off-by: Jakub Kicinski --- 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); From 049584807f1d797fc3078b68035450a9769eb5c3 Mon Sep 17 00:00:00 2001 From: Dongli Zhang Date: Wed, 24 Jul 2024 10:04:52 -0700 Subject: [PATCH 2/2] tun: add missing verification for short frame The cited commit missed to check against the validity of the frame length in the tun_xdp_one() path, which could cause a corrupted skb to be sent downstack. Even before the skb is transmitted, the tun_xdp_one-->eth_type_trans() may access the Ethernet header although it can be less 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, tun_get_user() already prohibits short frame which has the length less than Ethernet header size from being transmitted for IFF_TAP. This is to drop any frame shorter than the Ethernet header size just like how tun_get_user() does. CVE: CVE-2024-41091 Inspired-by: https://lore.kernel.org/netdev/1717026141-25716-1-git-send-email-si-wei.liu@oracle.com/ Fixes: 043d222f93ab ("tuntap: accept an array of XDP buffs through sendmsg()") Cc: stable@vger.kernel.org Signed-off-by: Dongli Zhang Reviewed-by: Si-Wei Liu Reviewed-by: Willem de Bruijn Reviewed-by: Paolo Abeni Reviewed-by: Jason Wang Link: https://patch.msgid.link/20240724170452.16837-3-dongli.zhang@oracle.com Signed-off-by: Jakub Kicinski --- drivers/net/tun.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 9b24861464bc..1d06c560c5e6 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -2455,6 +2455,9 @@ static int tun_xdp_one(struct tun_struct *tun, bool skb_xdp = false; struct page *page; + if (unlikely(datasize < ETH_HLEN)) + return -EINVAL; + xdp_prog = rcu_dereference(tun->xdp_prog); if (xdp_prog) { if (gso->gso_type) {