| From b08afc81c60607a4f736f418f2e3eb06087f1a35 Mon Sep 17 00:00:00 2001 |
| From: Donatas Abraitis <donatas@opensourcerouting.org> |
| Date: Fri, 20 Oct 2023 17:49:18 +0300 |
| Subject: [PATCH] bgpd: Handle MP_REACH_NLRI malformed packets with session |
| reset |
| |
| Avoid crashing bgpd. |
| |
| ``` |
| (gdb) |
| bgp_mp_reach_parse (args=<optimized out>, mp_update=0x7fffffffe140) at bgpd/bgp_attr.c:2341 |
| 2341 stream_get(&attr->mp_nexthop_global, s, IPV6_MAX_BYTELEN); |
| (gdb) |
| stream_get (dst=0x7fffffffe1ac, s=0x7ffff0006e80, size=16) at lib/stream.c:320 |
| 320 { |
| (gdb) |
| 321 STREAM_VERIFY_SANE(s); |
| (gdb) |
| 323 if (STREAM_READABLE(s) < size) { |
| (gdb) |
| 34 return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest)); |
| (gdb) |
| |
| Thread 1 "bgpd" received signal SIGSEGV, Segmentation fault. |
| 0x00005555556e37be in route_set_aspath_prepend (rule=0x555555aac0d0, prefix=0x7fffffffe050, |
| object=0x7fffffffdb00) at bgpd/bgp_routemap.c:2282 |
| 2282 if (path->attr->aspath->refcnt) |
| (gdb) |
| ``` |
| |
| With the configuration: |
| |
| ``` |
| 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 |
| redistribute connected |
| neighbor 127.0.0.1 default-originate |
| neighbor 127.0.0.1 route-map RM_IN in |
| exit-address-family |
| ! |
| route-map RM_IN permit 10 |
| set as-path prepend 200 |
| exit |
| ``` |
| |
| Reported-by: Iggy Frankovic <iggyfran@amazon.com> |
| Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org> |
| Upstream-Status: Backport [https://github.com/FRRouting/frr/commit/b08afc81c60607a4f736f418f2e3eb06087f1a35] |
| CVE: CVE-2023-46752 |
| Signed-off-by: Jonas Gorski <jonas.gorski@bisdn.de> |
| --- |
| bgpd/bgp_attr.c | 6 +----- |
| bgpd/bgp_attr.h | 1 - |
| bgpd/bgp_packet.c | 6 +----- |
| 3 files changed, 2 insertions(+), 11 deletions(-) |
| |
| diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c |
| index 6925aff727e2..e7bb42a5d989 100644 |
| --- a/bgpd/bgp_attr.c |
| +++ b/bgpd/bgp_attr.c |
| @@ -2421,7 +2421,7 @@ int bgp_mp_reach_parse(struct bgp_attr_parser_args *args, |
| |
| mp_update->afi = afi; |
| mp_update->safi = safi; |
| - return BGP_ATTR_PARSE_EOR; |
| + return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_MAL_ATTR, 0); |
| } |
| |
| mp_update->afi = afi; |
| @@ -3759,10 +3759,6 @@ enum bgp_attr_parse_ret bgp_attr_parse(struct peer *peer, struct attr *attr, |
| goto done; |
| } |
| |
| - if (ret == BGP_ATTR_PARSE_EOR) { |
| - goto done; |
| - } |
| - |
| if (ret == BGP_ATTR_PARSE_ERROR) { |
| flog_warn(EC_BGP_ATTRIBUTE_PARSE_ERROR, |
| "%s: Attribute %s, parse error", peer->host, |
| diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h |
| index 961e5f122470..fc347e7a1b4b 100644 |
| --- a/bgpd/bgp_attr.h |
| +++ b/bgpd/bgp_attr.h |
| @@ -364,7 +364,6 @@ enum bgp_attr_parse_ret { |
| /* only used internally, send notify + convert to BGP_ATTR_PARSE_ERROR |
| */ |
| BGP_ATTR_PARSE_ERROR_NOTIFYPLS = -3, |
| - BGP_ATTR_PARSE_EOR = -4, |
| }; |
| |
| struct bpacket_attr_vec_arr; |
| diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c |
| index b585591e2f69..5ecf343b6657 100644 |
| --- a/bgpd/bgp_packet.c |
| +++ b/bgpd/bgp_packet.c |
| @@ -2397,8 +2397,7 @@ static int bgp_update_receive(struct peer_connection *connection, |
| * Non-MP IPv4/Unicast EoR is a completely empty UPDATE |
| * and MP EoR should have only an empty MP_UNREACH |
| */ |
| - if ((!update_len && !withdraw_len && nlris[NLRI_MP_UPDATE].length == 0) |
| - || (attr_parse_ret == BGP_ATTR_PARSE_EOR)) { |
| + if (!update_len && !withdraw_len && nlris[NLRI_MP_UPDATE].length == 0) { |
| afi_t afi = 0; |
| safi_t safi; |
| struct graceful_restart_info *gr_info; |
| @@ -2419,9 +2418,6 @@ static int bgp_update_receive(struct peer_connection *connection, |
| && nlris[NLRI_MP_WITHDRAW].length == 0) { |
| afi = nlris[NLRI_MP_WITHDRAW].afi; |
| safi = nlris[NLRI_MP_WITHDRAW].safi; |
| - } else if (attr_parse_ret == BGP_ATTR_PARSE_EOR) { |
| - afi = nlris[NLRI_MP_UPDATE].afi; |
| - safi = nlris[NLRI_MP_UPDATE].safi; |
| } |
| |
| if (afi && peer->afc[afi][safi]) { |
| -- |
| 2.42.1 |
| |