hostapd: Fix security problem
This fixes: CVE-2019-11555 "EAP-pwd message reassembly issue with unexpected fragment" https://w1.fi/security/2019-5/eap-pwd-message-reassembly-issue-with-unexpected-fragment.txt This shouöld not affect OpenWrt in the default settings as we do not use EAP-pwd. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
This commit is contained in:
		@@ -7,7 +7,7 @@
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include $(TOPDIR)/rules.mk
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					include $(TOPDIR)/rules.mk
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PKG_NAME:=hostapd
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					PKG_NAME:=hostapd
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PKG_RELEASE:=7
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					PKG_RELEASE:=8
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PKG_SOURCE_URL:=http://w1.fi/hostap.git
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					PKG_SOURCE_URL:=http://w1.fi/hostap.git
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PKG_SOURCE_PROTO:=git
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					PKG_SOURCE_PROTO:=git
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@@ -0,0 +1,40 @@
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					From fe76f487e28bdc61940f304f153a954cf36935ea Mon Sep 17 00:00:00 2001
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					From: Jouni Malinen <jouni@codeaurora.org>
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					Date: Wed, 17 Apr 2019 01:55:32 +0300
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					Subject: [PATCH 1/3] EAP-pwd server: Fix reassembly buffer handling
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					data->inbuf allocation might fail and if that were to happen, the next
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					fragment in the exchange could have resulted in NULL pointer
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					dereference. Unexpected fragment with more bit might also be able to
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					trigger this. Fix that by explicitly checking for data->inbuf to be
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					available before using it.
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					Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
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					---
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					 src/eap_server/eap_server_pwd.c | 8 +++++++-
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					 1 file changed, 7 insertions(+), 1 deletion(-)
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					--- a/src/eap_server/eap_server_pwd.c
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					+++ b/src/eap_server/eap_server_pwd.c
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					@@ -947,6 +947,12 @@ static void eap_pwd_process(struct eap_s
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					 	 * the first and all intermediate fragments have the M bit set
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					 	 */
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					 	if (EAP_PWD_GET_MORE_BIT(lm_exch) || data->in_frag_pos) {
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					+		if (!data->inbuf) {
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					+			wpa_printf(MSG_DEBUG,
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					+				   "EAP-pwd: No buffer for reassembly");
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					+			eap_pwd_state(data, FAILURE);
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					+			return;
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					+		}
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					 		if ((data->in_frag_pos + len) > wpabuf_size(data->inbuf)) {
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					 			wpa_printf(MSG_DEBUG, "EAP-pwd: Buffer overflow "
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					 				   "attack detected! (%d+%d > %d)",
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					@@ -967,7 +973,7 @@ static void eap_pwd_process(struct eap_s
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					 	 * last fragment won't have the M bit set (but we're obviously
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					 	 * buffering fragments so that's how we know it's the last)
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					 	 */
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					-	if (data->in_frag_pos) {
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					+	if (data->in_frag_pos && data->inbuf) {
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					 		pos = wpabuf_head_u8(data->inbuf);
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					 		len = data->in_frag_pos;
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					 		wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
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@@ -0,0 +1,40 @@
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					From d2d1a324ce937628e4d9d9999fe113819b7d4478 Mon Sep 17 00:00:00 2001
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					From: Jouni Malinen <jouni@codeaurora.org>
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					Date: Wed, 17 Apr 2019 02:21:20 +0300
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					Subject: [PATCH 3/3] EAP-pwd peer: Fix reassembly buffer handling
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					Unexpected fragment might result in data->inbuf not being allocated
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					before processing and that could have resulted in NULL pointer
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					dereference. Fix that by explicitly checking for data->inbuf to be
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					available before using it.
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					Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
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					---
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					 src/eap_peer/eap_pwd.c | 9 ++++++++-
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					 1 file changed, 8 insertions(+), 1 deletion(-)
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					--- a/src/eap_peer/eap_pwd.c
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					+++ b/src/eap_peer/eap_pwd.c
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					@@ -969,6 +969,13 @@ eap_pwd_process(struct eap_sm *sm, void
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					 	 * buffer and ACK the fragment
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					 	 */
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					 	if (EAP_PWD_GET_MORE_BIT(lm_exch) || data->in_frag_pos) {
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					+		if (!data->inbuf) {
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					+			wpa_printf(MSG_DEBUG,
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					+				   "EAP-pwd: No buffer for reassembly");
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					+			ret->methodState = METHOD_DONE;
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					+			ret->decision = DECISION_FAIL;
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					+			return NULL;
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					+		}
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					 		data->in_frag_pos += len;
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					 		if (data->in_frag_pos > wpabuf_size(data->inbuf)) {
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					 			wpa_printf(MSG_INFO, "EAP-pwd: Buffer overflow attack "
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					@@ -995,7 +1002,7 @@ eap_pwd_process(struct eap_sm *sm, void
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					 	/*
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					 	 * we're buffering and this is the last fragment
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					 	 */
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					-	if (data->in_frag_pos) {
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					+	if (data->in_frag_pos && data->inbuf) {
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					 		wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
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					 			   (int) len);
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					 		pos = wpabuf_head_u8(data->inbuf);
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