Resolves: RHEL-3541 - Incorrect handling of a error in parsing of an invalid section of a BGP update can de-peer a router

0014-CVE-2023-38802.patch

@@ -0,0 +1,129 @@
+From 46817adab03802355c3cce7b753c7a735bdcc5ae Mon Sep 17 00:00:00 2001
+From: Donatas Abraitis <donatas@opensourcerouting.org>
+Date: Thu, 13 Jul 2023 22:32:03 +0300
+Subject: [PATCH] bgpd: Use treat-as-withdraw for tunnel encapsulation
+ attribute
+
+Before this path we used session reset method, which is discouraged by rfc7606.
+
+Handle this as rfc requires.
+
+Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
+(cherry picked from commit bcb6b58d9530173df41d3a3cbc4c600ee0b4b186)
+---
+ bgpd/bgp_attr.c | 61 ++++++++++++++++++++-----------------------------
+ 1 file changed, 25 insertions(+), 36 deletions(-)
+
+diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
+index 058fae23cbd..1c0803cfd8e 100644
+--- a/bgpd/bgp_attr.c
++++ b/bgpd/bgp_attr.c
+@@ -1301,6 +1301,7 @@ bgp_attr_malformed(struct bgp_attr_parser_args *args, uint8_t subcode,
+ 	case BGP_ATTR_LARGE_COMMUNITIES:
+ 	case BGP_ATTR_ORIGINATOR_ID:
+ 	case BGP_ATTR_CLUSTER_LIST:
++	case BGP_ATTR_ENCAP:
+ 		return BGP_ATTR_PARSE_WITHDRAW;
+ 	case BGP_ATTR_MP_REACH_NLRI:
+ 	case BGP_ATTR_MP_UNREACH_NLRI:
+@@ -2434,26 +2435,21 @@ bgp_attr_ipv6_ext_communities(struct bgp_attr_parser_args *args)
+ }
+ 
+ /* Parse Tunnel Encap attribute in an UPDATE */
+-static int bgp_attr_encap(uint8_t type, struct peer *peer, /* IN */
+-			  bgp_size_t length, /* IN: attr's length field */
+-			  struct attr *attr, /* IN: caller already allocated */
+-			  uint8_t flag,      /* IN: attr's flags field */
+-			  uint8_t *startp)
++static int bgp_attr_encap(struct bgp_attr_parser_args *args)
+ {
+-	bgp_size_t total;
+ 	uint16_t tunneltype = 0;
+-
+-	total = length + (CHECK_FLAG(flag, BGP_ATTR_FLAG_EXTLEN) ? 4 : 3);
++	struct peer *const peer = args->peer;
++	struct attr *const attr = args->attr;
++	bgp_size_t length = args->length;
++	uint8_t type = args->type;
++	uint8_t flag = args->flags;
+ 
+ 	if (!CHECK_FLAG(flag, BGP_ATTR_FLAG_TRANS)
+ 	    || !CHECK_FLAG(flag, BGP_ATTR_FLAG_OPTIONAL)) {
+-		zlog_info(
+-			"Tunnel Encap attribute flag isn't optional and transitive %d",
+-			flag);
+-		bgp_notify_send_with_data(peer, BGP_NOTIFY_UPDATE_ERR,
+-					  BGP_NOTIFY_UPDATE_ATTR_FLAG_ERR,
+-					  startp, total);
+-		return -1;
++		zlog_err("Tunnel Encap attribute flag isn't optional and transitive %d",
++			 flag);
++		return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR,
++					  args->total);
+ 	}
+ 
+ 	if (BGP_ATTR_ENCAP == type) {
+@@ -2461,12 +2457,11 @@ static int bgp_attr_encap(uint8_t type, struct peer *peer, /* IN */
+ 		uint16_t tlv_length;
+ 
+ 		if (length < 4) {
+-			zlog_info(
++			zlog_err(
+ 				"Tunnel Encap attribute not long enough to contain outer T,L");
+-			bgp_notify_send_with_data(
+-				peer, BGP_NOTIFY_UPDATE_ERR,
+-				BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, startp, total);
+-			return -1;
++			return bgp_attr_malformed(args,
++						  BGP_NOTIFY_UPDATE_OPT_ATTR_ERR,
++						  args->total);
+ 		}
+ 		tunneltype = stream_getw(BGP_INPUT(peer));
+ 		tlv_length = stream_getw(BGP_INPUT(peer));
+@@ -2496,13 +2491,11 @@ static int bgp_attr_encap(uint8_t type, struct peer *peer, /* IN */
+ 		}
+ 
+ 		if (sublength > length) {
+-			zlog_info(
+-				"Tunnel Encap attribute sub-tlv length %d exceeds remaining length %d",
+-				sublength, length);
+-			bgp_notify_send_with_data(
+-				peer, BGP_NOTIFY_UPDATE_ERR,
+-				BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, startp, total);
+-			return -1;
++			zlog_err("Tunnel Encap attribute sub-tlv length %d exceeds remaining length %d",
++				 sublength, length);
++			return bgp_attr_malformed(args,
++						  BGP_NOTIFY_UPDATE_OPT_ATTR_ERR,
++						  args->total);
+ 		}
+ 
+ 		/* alloc and copy sub-tlv */
+@@ -2550,13 +2543,10 @@ static int bgp_attr_encap(uint8_t type, struct peer *peer, /* IN */
+ 
+ 	if (length) {
+ 		/* spurious leftover data */
+-		zlog_info(
+-			"Tunnel Encap attribute length is bad: %d leftover octets",
+-			length);
+-		bgp_notify_send_with_data(peer, BGP_NOTIFY_UPDATE_ERR,
+-					  BGP_NOTIFY_UPDATE_OPT_ATTR_ERR,
+-					  startp, total);
+-		return -1;
++		zlog_err("Tunnel Encap attribute length is bad: %d leftover octets",
++			 length);
++		return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR,
++					  args->total);
+ 	}
+ 
+ 	return 0;
+@@ -3396,8 +3386,7 @@ enum bgp_attr_parse_ret bgp_attr_parse(struct peer *peer, struct attr *attr,
+ 		case BGP_ATTR_VNC:
+ #endif
+ 		case BGP_ATTR_ENCAP:
+-			ret = bgp_attr_encap(type, peer, length, attr, flag,
+-					     startp);
++			ret = bgp_attr_encap(&attr_args);
+ 			break;
+ 		case BGP_ATTR_PREFIX_SID:
+ 			ret = bgp_attr_prefix_sid(&attr_args);

frr.spec

@@ -7,7 +7,7 @@
 
 Name: frr
 Version: 8.3.1
-Release: 11%{?checkout}%{?dist}
+Release: 12%{?checkout}%{?dist}
 Summary: Routing daemon
 License: GPLv2+
 URL: http://www.frrouting.org
@@ -76,6 +76,7 @@ Patch0010: 0010-CVE-2022-43681.patch
 Patch0011: 0011-CVE-2022-40318.patch
 Patch0012: 0012-bfd-not-working-in-vrf.patch
 Patch0013: 0013-bgpd-maxttl-ebgp-multihop.patch
+Patch0014: 0014-CVE-2023-38802.patch
 
 %description
 FRRouting is free software that manages TCP/IP based routing protocols. It takes
@@ -281,6 +282,9 @@ make check PYTHON=%{__python3}
 %endif
 
 %changelog
+* Fri Oct 13 2023 Michal Ruprich <mruprich@redhat.com> - 8.3.1-12
+- Resolves: RHEL-3541 - Incorrect handling of a error in parsing of an invalid section of a BGP update can de-peer a router
+
 * Thu Sep 21 2023 Carlos Goncalves <cgoncalves@redhat.com> - 8.3.1-11
 - Resolves: RHEL-2263 - bgpd: Do not explicitly print MAXTTL value for ebgp-multihop vty output