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From 7490f281f09a8455c48e19b0cf1b99ab758ee4f4 Mon Sep 17 00:00:00 2001
From: Qian Chen <cq674350529@163.com>
Date: Tue, 20 Dec 2022 09:36:08 -0500
Subject: [PATCH] lldp: Fix bugs when parsing malformed AutoAttach.
The OVS LLDP implementation includes support for AutoAttach standard, which
the 'upstream' lldpd project does not include. As part of adding this
support, the message parsing for these TLVs did not include proper length
checks for the LLDP_TLV_AA_ELEMENT_SUBTYPE and the
LLDP_TLV_AA_ISID_VLAN_ASGNS_SUBTYPE elements. The result is that a message
without a proper boundary will cause an overread of memory, and lead to
undefined results, including crashes or other unidentified behavior.
The fix is to introduce proper bounds checking for these elements. Introduce
a unit test to ensure that we have some proper rejection in this code
base in the future.
Fixes: be53a5c447c3 ("auto-attach: Initial support for Auto-Attach standard")
Upstream-Status: Backport from upstream [https://github.com/openvswitch/ovs/commit/7490f281f09a8455c48e19b0cf1b99ab758ee4f4]
CVE: CVE-2022-4337 - openvswitch: Out-of-Bounds Read in Organization Specific TLV
CVE: CVE-2022-4338 - openvswitch: Integer Underflow in Organization Specific TLV
Signed-off-by: Qian Chen <cq674350529@163.com>
Co-authored-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
---
lib/lldp/lldp.c | 2 ++
tests/ofproto-dpif.at | 19 +++++++++++++++++++
2 files changed, 21 insertions(+)
diff --git a/lib/lldp/lldp.c b/lib/lldp/lldp.c
index dfeb2a800..6fdcfef56 100644
--- a/lib/lldp/lldp.c
+++ b/lib/lldp/lldp.c
@@ -583,6 +583,7 @@ lldp_decode(struct lldpd *cfg OVS_UNUSED, char *frame, int s,
switch(tlv_subtype) {
case LLDP_TLV_AA_ELEMENT_SUBTYPE:
+ CHECK_TLV_SIZE(50, "ELEMENT");
PEEK_BYTES(&msg_auth_digest, sizeof msg_auth_digest);
aa_element_dword = PEEK_UINT32;
@@ -629,6 +630,7 @@ lldp_decode(struct lldpd *cfg OVS_UNUSED, char *frame, int s,
break;
case LLDP_TLV_AA_ISID_VLAN_ASGNS_SUBTYPE:
+ CHECK_TLV_SIZE(36, "ISID_VLAN_ASGNS");
PEEK_BYTES(&msg_auth_digest, sizeof msg_auth_digest);
/* Subtract off tlv type and length (2Bytes) + OUI (3B) +
diff --git a/tests/ofproto-dpif.at b/tests/ofproto-dpif.at
index eb4cd1896..fa6111c1e 100644
--- a/tests/ofproto-dpif.at
+++ b/tests/ofproto-dpif.at
@@ -62,6 +62,25 @@ AT_CHECK([ovs-appctl coverage/read-counter rev_reconfigure], [0], [dnl
OVS_VSWITCHD_STOP
AT_CLEANUP
+AT_SETUP([ofproto-dpif - malformed lldp autoattach tlv])
+OVS_VSWITCHD_START()
+add_of_ports br0 1
+
+dnl Enable lldp
+AT_CHECK([ovs-vsctl set interface p1 lldp:enable=true])
+
+dnl Send a malformed lldp packet
+packet="0180c200000ef6b426aa5f0088cc020704f6b426aa5f000403057632060200780c"dnl
+"5044454144424545464445414442454546444541444245454644454144424545464445414"dnl
+"4424545464445414442454546444541444245454644454144424545464445414442454546"dnl
+"4445414442454546fe0500040d0c010000"
+AT_CHECK([ovs-appctl netdev-dummy/receive p1 "$packet"], [0], [stdout])
+
+OVS_WAIT_UNTIL([grep -q "ISID_VLAN_ASGNS TLV too short" ovs-vswitchd.log])
+
+OVS_VSWITCHD_STOP(["/|WARN|ISID_VLAN_ASGNS TLV too short received on/d"])
+AT_CLEANUP
+
AT_SETUP([ofproto-dpif - active-backup bonding (with primary)])
dnl Create br0 with members p1, p2 and p7, creating bond0 with p1 and
--
2.34.1
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