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From ad32e04f3db364694edc678327326ae6b771db9e Mon Sep 17 00:00:00 2001
From: Donatas Abraitis <donatas@opensourcerouting.org>
Date: Tue, 5 Sep 2023 11:30:53 +0000
Subject: [PATCH 1/2] 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>
CVE: CVE-2023-38802
Upstream-Status: Backport [https://github.com/FRRouting/frr/commit/bcb6b58d9530173df41d3a3cbc4c600ee0b4b186]
Signed-off-by: Narpat Mali <narpat.mali@windriver.com>
---
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 5d06991e2..b10a60351 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -1310,6 +1310,7 @@ 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:
@@ -2411,26 +2412,21 @@ 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) {
@@ -2438,12 +2434,11 @@ 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));
@@ -2473,13 +2468,11 @@ 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 */
@@ -2527,13 +2520,10 @@ 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;
@@ -3332,8 +3322,7 @@ bgp_attr_parse_ret_t 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);
--
2.40.0
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