netdev - [PATCH V3 net-next] ixgbe: Avoid unaligned access in ixgbe

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-next>] [day] [month] [year] [list]

Message-ID: <20160314194716.GM5084@oracle.com>
Date:	Mon, 14 Mar 2016 15:47:16 -0400
From:	Sowmini Varadhan <sowmini.varadhan@...cle.com>
To:	intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
	alexander.duyck@...il.com
Cc:	jeffrey.t.kirsher@...el.com, jesse.brandeburg@...el.com,
	shannon.nelson@...el.com, carolyn.wyborny@...el.com,
	donald.c.skidmore@...el.com, bruce.w.allan@...el.com,
	john.ronciak@...el.com, mitch.a.williams@...el.com,
	sowmini.varadhan@...cle.com
Subject: [PATCH V3 net-next] ixgbe: Avoid unaligned access in ixgbe_atr() for
 LLC packets


For LLC based protocols like lldp, stp etc., the ethernet header
is an 802.3 header with a h_proto that is not 0x800, 0x86dd, or
even 0x806.  In this world, the skb_network_header() points at
the DSAP/SSAP/..  and is not likely to be NET_IP_ALIGNed in
ixgbe_atr().

With LLC, drivers are not likely to correctly find IPVERSION,
or "6", at hdr.ipv4->version, but will instead just needlessly
trigger an unaligned access. (IPv4/IPv6 over LLC is almost never
implemented).

The unaligned access is thus avoidable: bail out quickly after
examining skb->protocol. The only Ethernet II protocols handled
are IPv4 and IPv6

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@...cle.com>
---
v2: Alexander Duyck comments
v3: filter out all ethertypes  except for Ethernet II and (IPv4 or IPv6)

 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 4d6223d..aeab2fe 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -7574,6 +7574,11 @@ static void ixgbe_atr(struct ixgbe_ring *ring,
 	if (!ring->atr_sample_rate)
 		return;
 
+	/* this function only handles IPv4 or IPv6 */
+	if (first->protocol != htons(ETH_P_IP) &&
+	    first->protocol != htons(ETH_P_IPV6))
+		return;
+
 	ring->atr_count++;
 
 	/* snag network header to get L4 type and address */
-- 
1.7.1