[OE-core] [PATCH][dizzy] dhcp: CVE-2015-8605
mariano.lopez at linux.intel.com
mariano.lopez at linux.intel.com
Thu Mar 10 12:00:21 UTC 2016
From: Mariano Lopez <mariano.lopez at linux.intel.com>
ISC DHCP allows remote attackers to cause a denial of
service (application crash) via an invalid length field
in a UDP IPv4 packet.
Signed-off-by: Mariano Lopez <mariano.lopez at linux.intel.com>
---
.../dhcp/dhcp/CVE-2015-8605.patch | 99 ++++++++++++++++
.../dhcp/dhcp/CVE-2015-8605_1.patch | 131 +++++++++++++++++++++
meta/recipes-connectivity/dhcp/dhcp_4.3.0.bb | 2 +
3 files changed, 232 insertions(+)
create mode 100644 meta/recipes-connectivity/dhcp/dhcp/CVE-2015-8605.patch
create mode 100644 meta/recipes-connectivity/dhcp/dhcp/CVE-2015-8605_1.patch
diff --git a/meta/recipes-connectivity/dhcp/dhcp/CVE-2015-8605.patch b/meta/recipes-connectivity/dhcp/dhcp/CVE-2015-8605.patch
new file mode 100644
index 0000000..923d5d5
--- /dev/null
+++ b/meta/recipes-connectivity/dhcp/dhcp/CVE-2015-8605.patch
@@ -0,0 +1,99 @@
+Solves CVE-2015-8605 that caused DoS when an invalid lenght field in IPv4 UDP
+was recived by the server.
+
+Upstream-Status: Backport
+CVE: CVE-2015-8605
+
+Signed-off-by: Mariano Lopez <mariano.lopez at linux.intel.com>
+
+=======================================================================
+diff --git a/common/packet.c b/common/packet.c
+index b530432..e600e37 100644
+--- a/common/packet.c
++++ b/common/packet.c
+@@ -220,7 +220,28 @@ ssize_t decode_hw_header (interface, buf, bufix, from)
+ }
+ }
+
+-/* UDP header and IP header decoded together for convenience. */
++/*!
++ *
++ * \brief UDP header and IP header decoded together for convenience.
++ *
++ * Attempt to decode the UDP and IP headers and, if necessary, checksum
++ * the packet.
++ *
++ * \param inteface - the interface on which the packet was recevied
++ * \param buf - a pointer to the buffer for the received packet
++ * \param bufix - where to start processing the buffer, previous
++ * routines may have processed parts of the buffer already
++ * \param from - space to return the address of the packet sender
++ * \param buflen - remaining length of the buffer, this will have been
++ * decremented by bufix by the caller
++ * \param rbuflen - space to return the length of the payload from the udp
++ * header
++ * \param csum_ready - indication if the checksum is valid for use
++ * non-zero indicates the checksum should be validated
++ *
++ * \return - the index to the first byte of the udp payload (that is the
++ * start of the DHCP packet
++ */
+
+ ssize_t
+ decode_udp_ip_header(struct interface_info *interface,
+@@ -231,7 +252,7 @@ decode_udp_ip_header(struct interface_info *interface,
+ unsigned char *data;
+ struct ip ip;
+ struct udphdr udp;
+- unsigned char *upp, *endbuf;
++ unsigned char *upp;
+ u_int32_t ip_len, ulen, pkt_len;
+ static unsigned int ip_packets_seen = 0;
+ static unsigned int ip_packets_bad_checksum = 0;
+@@ -241,11 +262,8 @@ decode_udp_ip_header(struct interface_info *interface,
+ static unsigned int udp_packets_length_overflow = 0;
+ unsigned len;
+
+- /* Designate the end of the input buffer for bounds checks. */
+- endbuf = buf + bufix + buflen;
+-
+ /* Assure there is at least an IP header there. */
+- if ((buf + bufix + sizeof(ip)) > endbuf)
++ if (sizeof(ip) > buflen)
+ return -1;
+
+ /* Copy the IP header into a stack aligned structure for inspection.
+@@ -257,13 +275,17 @@ decode_udp_ip_header(struct interface_info *interface,
+ ip_len = (*upp & 0x0f) << 2;
+ upp += ip_len;
+
+- /* Check the IP packet length. */
++ /* Check packet lengths are within the buffer:
++ * first the ip header (ip_len)
++ * then the packet length from the ip header (pkt_len)
++ * then the udp header (ip_len + sizeof(udp)
++ * We are liberal in what we accept, the udp payload should fit within
++ * pkt_len, but we only check against the full buffer size.
++ */
+ pkt_len = ntohs(ip.ip_len);
+- if (pkt_len > buflen)
+- return -1;
+-
+- /* Assure after ip_len bytes that there is enough room for a UDP header. */
+- if ((upp + sizeof(udp)) > endbuf)
++ if ((ip_len > buflen) ||
++ (pkt_len > buflen) ||
++ ((ip_len + sizeof(udp)) > buflen))
+ return -1;
+
+ /* Copy the UDP header into a stack aligned structure for inspection. */
+@@ -284,7 +306,8 @@ decode_udp_ip_header(struct interface_info *interface,
+ return -1;
+
+ udp_packets_length_checked++;
+- if ((upp + ulen) > endbuf) {
++ /* verify that the payload length from the udp packet fits in the buffer */
++ if ((ip_len + ulen) > buflen) {
+ udp_packets_length_overflow++;
+ if (((udp_packets_length_checked > 4) &&
+ (udp_packets_length_overflow != 0)) &&
diff --git a/meta/recipes-connectivity/dhcp/dhcp/CVE-2015-8605_1.patch b/meta/recipes-connectivity/dhcp/dhcp/CVE-2015-8605_1.patch
new file mode 100644
index 0000000..37a3d72
--- /dev/null
+++ b/meta/recipes-connectivity/dhcp/dhcp/CVE-2015-8605_1.patch
@@ -0,0 +1,131 @@
+This patch is needed for the CVE-2015-8605 that caused DoS when an invalid lenght field in IPv4 UDP
+was recived by the server.
+
+Upstream-Status: Backport
+CVE: CVE-2015-8605
+
+Signed-off-by: Mariano Lopez <mariano.lopez at linux.intel.com>
+---
+From 0ce1aa94454ce9b50d592c08d7e0c559d38d3bc5 Mon Sep 17 00:00:00 2001
+From: Thomas Markwalder <tmark at isc.org>
+Date: Mon, 8 Sep 2014 09:31:32 -0400
+Subject: [PATCH] [master] Corrected error in UDP bad packet logging
+
+ Merges in rt36897
+---
+ common/packet.c | 55 +++++++++++++++++++++++++++++++++++--------------------
+ 1 file changed, 35 insertions(+), 20 deletions(-)
+
+diff --git a/common/packet.c b/common/packet.c
+index 45e96e8..7460f3d 100644
+--- a/common/packet.c
++++ b/common/packet.c
+@@ -3,7 +3,7 @@
+ Packet assembly code, originally contributed by Archie Cobbs. */
+
+ /*
+- * Copyright (c) 2009,2012 by Internet Systems Consortium, Inc. ("ISC")
++ * Copyright (c) 2009,2012,2014 by Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (c) 2004,2005,2007 by Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (c) 1996-2003 by Internet Software Consortium
+ *
+@@ -234,12 +234,12 @@ decode_udp_ip_header(struct interface_info *interface,
+ unsigned char *upp, *endbuf;
+ u_int32_t ip_len, ulen, pkt_len;
+ u_int32_t sum, usum;
+- static int ip_packets_seen;
+- static int ip_packets_bad_checksum;
+- static int udp_packets_seen;
+- static int udp_packets_bad_checksum;
+- static int udp_packets_length_checked;
+- static int udp_packets_length_overflow;
++ static unsigned int ip_packets_seen = 0;
++ static unsigned int ip_packets_bad_checksum = 0;
++ static unsigned int udp_packets_seen = 0;
++ static unsigned int udp_packets_bad_checksum = 0;
++ static unsigned int udp_packets_length_checked = 0;
++ static unsigned int udp_packets_length_overflow = 0;
+ unsigned len;
+
+ /* Designate the end of the input buffer for bounds checks. */
+@@ -287,10 +287,10 @@ decode_udp_ip_header(struct interface_info *interface,
+ udp_packets_length_checked++;
+ if ((upp + ulen) > endbuf) {
+ udp_packets_length_overflow++;
+- if ((udp_packets_length_checked > 4) &&
+- ((udp_packets_length_checked /
+- udp_packets_length_overflow) < 2)) {
+- log_info("%d udp packets in %d too long - dropped",
++ if (((udp_packets_length_checked > 4) &&
++ (udp_packets_length_overflow != 0)) &&
++ ((udp_packets_length_checked / udp_packets_length_overflow) < 2)) {
++ log_info("%u udp packets in %u too long - dropped",
+ udp_packets_length_overflow,
+ udp_packets_length_checked);
+ udp_packets_length_overflow = 0;
+@@ -299,22 +299,31 @@ decode_udp_ip_header(struct interface_info *interface,
+ return -1;
+ }
+
+- if ((ulen < sizeof(udp)) || ((upp + ulen) > endbuf))
+- return -1;
++ /* If at least 5 with less than 50% bad, start over */
++ if (udp_packets_length_checked > 4) {
++ udp_packets_length_overflow = 0;
++ udp_packets_length_checked = 0;
++ }
+
+ /* Check the IP header checksum - it should be zero. */
+- ++ip_packets_seen;
++ ip_packets_seen++;
+ if (wrapsum (checksum (buf + bufix, ip_len, 0))) {
+ ++ip_packets_bad_checksum;
+- if (ip_packets_seen > 4 &&
+- (ip_packets_seen / ip_packets_bad_checksum) < 2) {
+- log_info ("%d bad IP checksums seen in %d packets",
++ if (((ip_packets_seen > 4) && (ip_packets_bad_checksum != 0)) &&
++ ((ip_packets_seen / ip_packets_bad_checksum) < 2)) {
++ log_info ("%u bad IP checksums seen in %u packets",
+ ip_packets_bad_checksum, ip_packets_seen);
+ ip_packets_seen = ip_packets_bad_checksum = 0;
+ }
+ return -1;
+ }
+
++ /* If at least 5 with less than 50% bad, start over */
++ if (ip_packets_seen > 4) {
++ ip_packets_bad_checksum = 0;
++ ip_packets_seen = 0;
++ }
++
+ /* Copy out the IP source address... */
+ memcpy(&from->sin_addr, &ip.ip_src, 4);
+
+@@ -339,15 +348,21 @@ decode_udp_ip_header(struct interface_info *interface,
+ udp_packets_seen++;
+ if (usum && usum != sum) {
+ udp_packets_bad_checksum++;
+- if (udp_packets_seen > 4 &&
+- (udp_packets_seen / udp_packets_bad_checksum) < 2) {
+- log_info ("%d bad udp checksums in %d packets",
++ if (((udp_packets_seen > 4) && (udp_packets_bad_checksum != 0)) &&
++ ((udp_packets_seen / udp_packets_bad_checksum) < 2)) {
++ log_info ("%u bad udp checksums in %u packets",
+ udp_packets_bad_checksum, udp_packets_seen);
+ udp_packets_seen = udp_packets_bad_checksum = 0;
+ }
+ return -1;
+ }
+
++ /* If at least 5 with less than 50% bad, start over */
++ if (udp_packets_seen > 4) {
++ udp_packets_bad_checksum = 0;
++ udp_packets_seen = 0;
++ }
++
+ /* Copy out the port... */
+ memcpy (&from -> sin_port, &udp.uh_sport, sizeof udp.uh_sport);
+
+--
+2.6.2
+
diff --git a/meta/recipes-connectivity/dhcp/dhcp_4.3.0.bb b/meta/recipes-connectivity/dhcp/dhcp_4.3.0.bb
index 13bcceb..523808d 100644
--- a/meta/recipes-connectivity/dhcp/dhcp_4.3.0.bb
+++ b/meta/recipes-connectivity/dhcp/dhcp_4.3.0.bb
@@ -6,6 +6,8 @@ SRC_URI += "file://dhcp-3.0.3-dhclient-dbus.patch;striplevel=0 \
file://fixsepbuild.patch \
file://dhclient-script-drop-resolv.conf.dhclient.patch \
file://replace-ifconfig-route.patch \
+ file://CVE-2015-8605_1.patch \
+ file://CVE-2015-8605.patch \
"
SRC_URI[md5sum] = "1020d77e1a4c1f01b76279caff9beb80"
--
2.6.2
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