[OE-core] [PATCH] dhcp: CVE-2016-2774

[Catalin Enache]

ISC DHCP 4.1.x before 4.1-ESV-R13 and 4.2.x and 4.3.x before
4.3.4 does not restrict the number of concurrent TCP sessions,
which allows remote attackers to cause a denial of service
(INSIST assertion failure or request-processing outage)
by establishing many sessions.

http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-2774

Signed-off-by: Catalin Enache <catalin.enache at windriver.com>
---
 .../dhcp/dhcp/CVE-2016-2774.patch                  | 65 ++++++++++++++++++++++
 meta/recipes-connectivity/dhcp/dhcp_4.3.3.bb       |  1 +
 2 files changed, 66 insertions(+)
 create mode 100644 meta/recipes-connectivity/dhcp/dhcp/CVE-2016-2774.patch

diff --git a/meta/recipes-connectivity/dhcp/dhcp/CVE-2016-2774.patch b/meta/recipes-connectivity/dhcp/dhcp/CVE-2016-2774.patch
new file mode 100644
index 0000000..93ff54a
--- /dev/null
+++ b/meta/recipes-connectivity/dhcp/dhcp/CVE-2016-2774.patch
@@ -0,0 +1,65 @@
+From b9f56d578ebfd649b5d829960540859ac6ca931c Mon Sep 17 00:00:00 2001
+From: Catalin Enache <catalin.enache at windriver.com>
+Date: Tue, 12 Apr 2016 18:23:31 +0300
+Subject: [PATCH] Add patch to limit the value of an fd we accept for a
+ connection.
+
+Upstream-Status: Backport
+
+By limiting the highest value we accept for an fd we limit the number
+of connections.
+
+Author: Shawn Routhier <sar at isc.org>
+Signed-off-by: Catalin Enache <catalin.enache at windriver.com>
+---
+ includes/site.h   | 6 ++++++
+ omapip/listener.c | 9 +++++++--
+ 3 files changed, 18 insertions(+), 2 deletions(-)
+
+diff --git a/includes/site.h b/includes/site.h
+index 9c33de3..df020c8 100644
+--- a/includes/site.h
++++ b/includes/site.h
+@@ -290,6 +290,12 @@
+    this option will be removed at some time. */
+ /* #define INCLUDE_OLD_DHCP_ISC_ERROR_CODES */
+ 
++/* Limit the value of a file descriptor the serve will use
++   when accepting a connecting request.  This can be used to
++   limit the number of TCP connections that the server will
++   allow at one time.  A value of 0 means there is no limit.*/
++#define MAX_FD_VALUE 200
++
+ /* Include definitions for various options.  In general these
+    should be left as is, but if you have already defined one
+    of these and prefer your definition you can comment the 
+diff --git a/omapip/listener.c b/omapip/listener.c
+index 8bdcdbd..61473cf 100644
+--- a/omapip/listener.c
++++ b/omapip/listener.c
+@@ -3,7 +3,7 @@
+    Subroutines that support the generic listener object. */
+ 
+ /*
+- * Copyright (c) 2012,2014 by Internet Systems Consortium, Inc. ("ISC")
++ * Copyright (c) 2012,2014,2016 by Internet Systems Consortium, Inc. ("ISC")
+  * Copyright (c) 2004,2007,2009 by Internet Systems Consortium, Inc. ("ISC")
+  * Copyright (c) 1999-2003 by Internet Software Consortium
+  *
+@@ -233,7 +233,12 @@ isc_result_t omapi_accept (omapi_object_t *h)
+ 			return ISC_R_NORESOURCES;
+ 		return ISC_R_UNEXPECTED;
+ 	}
+-	
++
++	if ((MAX_FD_VALUE != 0) && (socket > MAX_FD_VALUE)) {
++		close(socket);
++		return (ISC_R_NORESOURCES);
++	}
++
+ #if defined (TRACING)
+ 	/* If we're recording a trace, remember the connection. */
+ 	if (trace_record ()) {
+-- 
+2.7.4
+
diff --git a/meta/recipes-connectivity/dhcp/dhcp_4.3.3.bb b/meta/recipes-connectivity/dhcp/dhcp_4.3.3.bb
index 970617f..4e8cd27 100644
--- a/meta/recipes-connectivity/dhcp/dhcp_4.3.3.bb
+++ b/meta/recipes-connectivity/dhcp/dhcp_4.3.3.bb
@@ -8,6 +8,7 @@ SRC_URI += "file://dhcp-3.0.3-dhclient-dbus.patch;striplevel=0 \
             file://replace-ifconfig-route.patch \
             file://CVE-2015-8605.patch \
             file://0001-site.h-enable-gentle-shutdown.patch \
+            file://CVE-2016-2774.patch \
            "
 
 SRC_URI[md5sum] = "c5577b09c9017cdd319a11ff6364268e"
-- 
2.7.4