[Buildroot] [PATCH v1 1/2] package/busybox: udhcp CVE-2018-20679 patch
jared.bents at rockwellcollins.com
jared.bents at rockwellcollins.com
Wed Mar 6 14:22:30 UTC 2019
From: Jared Bents <jared.bents at rockwellcollins.com>
Patch to resolve CVE-2018-20679 which affects versions prior
to 1.30.0
More information can be found at:
https://nvd.nist.gov/vuln/detail/CVE-2018-20679
This applies to both master and 2019.02
Signed-off-by: Jared Bents <jared.bents at rockwellcollins.com>
---
...tions-are-indeed-4-byte-closes-11506.patch | 136 ++++++++++++++++++
1 file changed, 136 insertions(+)
create mode 100644 package/busybox/0004-udhcpc-check-that-4-byte-options-are-indeed-4-byte-closes-11506.patch
diff --git a/package/busybox/0004-udhcpc-check-that-4-byte-options-are-indeed-4-byte-closes-11506.patch b/package/busybox/0004-udhcpc-check-that-4-byte-options-are-indeed-4-byte-closes-11506.patch
new file mode 100644
index 0000000000..bc1a48bf4b
--- /dev/null
+++ b/package/busybox/0004-udhcpc-check-that-4-byte-options-are-indeed-4-byte-closes-11506.patch
@@ -0,0 +1,136 @@
+From 6d3b4bb24da9a07c263f3c1acf8df85382ff562c Mon Sep 17 00:00:00 2001
+From: Denys Vlasenko <vda.linux at googlemail.com>
+Date: Mon, 17 Dec 2018 18:07:18 +0100
+Subject: udhcpc: check that 4-byte options are indeed 4-byte, closes 11506
+
+function old new delta
+udhcp_get_option32 - 27 +27
+udhcp_get_option 231 248 +17
+------------------------------------------------------------------------------
+(add/remove: 1/0 grow/shrink: 1/0 up/down: 44/0) Total: 44 bytes
+
+Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
+---
+ networking/udhcp/common.c | 19 +++++++++++++++++++
+ networking/udhcp/common.h | 4 ++++
+ networking/udhcp/dhcpc.c | 6 +++---
+ networking/udhcp/dhcpd.c | 6 +++---
+ 4 files changed, 29 insertions(+), 6 deletions(-)
+
+diff --git a/networking/udhcp/common.c b/networking/udhcp/common.c
+index e5fd74f91..41b05b855 100644
+--- a/networking/udhcp/common.c
++++ b/networking/udhcp/common.c
+@@ -272,6 +272,15 @@ uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code)
+ goto complain; /* complain and return NULL */
+
+ if (optionptr[OPT_CODE] == code) {
++ if (optionptr[OPT_LEN] == 0) {
++ /* So far no valid option with length 0 known.
++ * Having this check means that searching
++ * for DHCP_MESSAGE_TYPE need not worry
++ * that returned pointer might be unsafe
++ * to dereference.
++ */
++ goto complain; /* complain and return NULL */
++ }
+ log_option("option found", optionptr);
+ return optionptr + OPT_DATA;
+ }
+@@ -289,6 +298,16 @@ uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code)
+ return NULL;
+ }
+
++uint8_t* FAST_FUNC udhcp_get_option32(struct dhcp_packet *packet, int code)
++{
++ uint8_t *r = udhcp_get_option(packet, code);
++ if (r) {
++ if (r[-1] != 4)
++ r = NULL;
++ }
++ return r;
++}
++
+ /* Return the position of the 'end' option (no bounds checking) */
+ int FAST_FUNC udhcp_end_option(uint8_t *optionptr)
+ {
+diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h
+index 7ad603d33..9511152ff 100644
+--- a/networking/udhcp/common.h
++++ b/networking/udhcp/common.h
+@@ -205,6 +205,10 @@ extern const uint8_t dhcp_option_lengths[] ALIGN1;
+ unsigned FAST_FUNC udhcp_option_idx(const char *name, const char *option_strings);
+
+ uint8_t *udhcp_get_option(struct dhcp_packet *packet, int code) FAST_FUNC;
++/* Same as above + ensures that option length is 4 bytes
++ * (returns NULL if size is different)
++ */
++uint8_t *udhcp_get_option32(struct dhcp_packet *packet, int code) FAST_FUNC;
+ int udhcp_end_option(uint8_t *optionptr) FAST_FUNC;
+ void udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt) FAST_FUNC;
+ #if ENABLE_UDHCPC || ENABLE_UDHCPD
+diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
+index 4b23e4d39..5b3fd531c 100644
+--- a/networking/udhcp/dhcpc.c
++++ b/networking/udhcp/dhcpc.c
+@@ -1691,7 +1691,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
+ * They say ISC DHCP client supports this case.
+ */
+ server_addr = 0;
+- temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
++ temp = udhcp_get_option32(&packet, DHCP_SERVER_ID);
+ if (!temp) {
+ bb_error_msg("no server ID, using 0.0.0.0");
+ } else {
+@@ -1718,7 +1718,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
+ struct in_addr temp_addr;
+ uint8_t *temp;
+
+- temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
++ temp = udhcp_get_option32(&packet, DHCP_LEASE_TIME);
+ if (!temp) {
+ bb_error_msg("no lease time with ACK, using 1 hour lease");
+ lease_seconds = 60 * 60;
+@@ -1813,7 +1813,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
+ uint32_t svid;
+ uint8_t *temp;
+
+- temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
++ temp = udhcp_get_option32(&packet, DHCP_SERVER_ID);
+ if (!temp) {
+ non_matching_svid:
+ log1("received DHCP NAK with wrong"
+diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c
+index a8cd3f03b..477856d11 100644
+--- a/networking/udhcp/dhcpd.c
++++ b/networking/udhcp/dhcpd.c
+@@ -640,7 +640,7 @@ static void add_server_options(struct dhcp_packet *packet)
+ static uint32_t select_lease_time(struct dhcp_packet *packet)
+ {
+ uint32_t lease_time_sec = server_config.max_lease_sec;
+- uint8_t *lease_time_opt = udhcp_get_option(packet, DHCP_LEASE_TIME);
++ uint8_t *lease_time_opt = udhcp_get_option32(packet, DHCP_LEASE_TIME);
+ if (lease_time_opt) {
+ move_from_unaligned32(lease_time_sec, lease_time_opt);
+ lease_time_sec = ntohl(lease_time_sec);
+@@ -987,7 +987,7 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
+ }
+
+ /* Get SERVER_ID if present */
+- server_id_opt = udhcp_get_option(&packet, DHCP_SERVER_ID);
++ server_id_opt = udhcp_get_option32(&packet, DHCP_SERVER_ID);
+ if (server_id_opt) {
+ uint32_t server_id_network_order;
+ move_from_unaligned32(server_id_network_order, server_id_opt);
+@@ -1011,7 +1011,7 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
+ }
+
+ /* Get REQUESTED_IP if present */
+- requested_ip_opt = udhcp_get_option(&packet, DHCP_REQUESTED_IP);
++ requested_ip_opt = udhcp_get_option32(&packet, DHCP_REQUESTED_IP);
+ if (requested_ip_opt) {
+ move_from_unaligned32(requested_nip, requested_ip_opt);
+ }
+--
+cgit v1.2.1
+
--
2.18.0
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