netdev - [PATCH net 1/2] vxlan: Don't assume linear buffers in error handler

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: <4875a7f58fc31701a14156978dd7d9abe9870908.1560205281.git.sbrivio@redhat.com>
Date:   Tue, 11 Jun 2019 00:27:05 +0200
From:   Stefano Brivio <sbrivio@...hat.com>
To:     David Miller <davem@...emloft.net>
Cc:     Guillaume Nault <gnault@...hat.com>,
        Eric Dumazet <edumazet@...gle.com>, netdev@...r.kernel.org
Subject: [PATCH net 1/2] vxlan: Don't assume linear buffers in error handler

In commit c3a43b9fec8a ("vxlan: ICMP error lookup handler") I wrongly
assumed buffers from icmp_socket_deliver() would be linear. This is not
the case: icmp_socket_deliver() only guarantees we have 8 bytes of linear
data.

Eric fixed this same issue for fou and fou6 in commits 26fc181e6cac
("fou, fou6: do not assume linear skbs") and 5355ed6388e2 ("fou, fou6:
avoid uninit-value in gue_err() and gue6_err()").

Use pskb_may_pull() instead of checking skb->len, and take into account
the fact we later access the VXLAN header with udp_hdr(), so we also
need to sum skb_transport_header() here.

Reported-by: Guillaume Nault <gnault@...hat.com>
Fixes: c3a43b9fec8a ("vxlan: ICMP error lookup handler")
Signed-off-by: Stefano Brivio <sbrivio@...hat.com>
---
 drivers/net/vxlan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 5994d5415a03..4c9bc29fe3d5 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1766,7 +1766,7 @@ static int vxlan_err_lookup(struct sock *sk, struct sk_buff *skb)
 	struct vxlanhdr *hdr;
 	__be32 vni;

-	if (skb->len < VXLAN_HLEN)
+	if (!pskb_may_pull(skb, skb_transport_offset(skb) + VXLAN_HLEN))
 		return -EINVAL;

 	hdr = vxlan_hdr(skb);
-- 
2.20.1