[ovs-dev] [PATCH 3/6] lldp: fix a buffer overflow when handling management address TLV
Fabrizio D'Angelo
fdangelo at redhat.com
Mon Oct 26 20:57:42 UTC 2020
From: Vincent Bernat <vincent at bernat.im>
Upstream commit:
commit a8d8006c06d9ac16ebcf33295cbd625c0847ca9b
Author: Vincent Bernat <vincent at bernat.im>
Date: Sun, 4 Oct 2015 01:50:38 +0200
lldp: fix a buffer overflow when handling management address TLV
When a remote device was advertising a too large management address
while still respecting TLV boundaries, lldpd would crash due to a buffer
overflow. However, the buffer being a static one, this buffer overflow
is not exploitable if hardening was not disabled. This bug exists since
version 0.5.6.
Co-authored-by: Fabrizio D'Angelo <fdangelo at redhat.com>
Signed-off-by: Fabrizio D'Angelo <fdangelo at redhat.com>
---
lib/lldp/lldp.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/lib/lldp/lldp.c b/lib/lldp/lldp.c
index 593c5e1c34..aaa8ec842a 100644
--- a/lib/lldp/lldp.c
+++ b/lib/lldp/lldp.c
@@ -530,6 +530,11 @@ lldp_decode(struct lldpd *cfg OVS_UNUSED, char *frame, int s,
case LLDP_TLV_MGMT_ADDR:
CHECK_TLV_SIZE(1, "Management address");
addr_str_length = PEEK_UINT8;
+ if (addr_str_length > sizeof(addr_str_buffer)) {
+ VLOG_WARN(name "too large management address on %s",
+ hardware->h_ifname);
+ goto malformed;
+ }
CHECK_TLV_SIZE(1 + addr_str_length, "Management address");
PEEK_BYTES(addr_str_buffer, addr_str_length);
addr_length = addr_str_length - 1;
@@ -554,7 +559,7 @@ lldp_decode(struct lldpd *cfg OVS_UNUSED, char *frame, int s,
break;
case LLDP_TLV_ORG:
- CHECK_TLV_SIZE(4, "Organisational");
+ CHECK_TLV_SIZE(1 + (int)sizeof(orgid), "Organisational");
PEEK_BYTES(orgid, sizeof orgid);
tlv_subtype = PEEK_UINT8;
if (memcmp(dot1, orgid, sizeof orgid) == 0) {
--
2.26.2
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