diff options
Diffstat (limited to '')
| -rw-r--r-- | debian/patches/CVE-2023-41358.patch | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/debian/patches/CVE-2023-41358.patch b/debian/patches/CVE-2023-41358.patch new file mode 100644 index 0000000..ff2f2b7 --- /dev/null +++ b/debian/patches/CVE-2023-41358.patch @@ -0,0 +1,100 @@ +From f291f1ee9434f56d4b185db0652794a92e313b00 Mon Sep 17 00:00:00 2001 +From: Donatas Abraitis <donatas@opensourcerouting.org> +Date: Tue, 22 Aug 2023 22:52:04 +0300 +Subject: [PATCH] bgpd: Do not process NLRIs if the attribute length is zero + +``` +3 0x00007f423aa42476 in __GI_raise (sig=sig@entry=11) at ../sysdeps/posix/raise.c:26 +4 0x00007f423aef9740 in core_handler (signo=11, siginfo=0x7fffc414deb0, context=<optimized out>) at lib/sigevent.c:246 +5 <signal handler called> +6 0x0000564dea2fc71e in route_set_aspath_prepend (rule=0x564debd66d50, prefix=0x7fffc414ea30, object=0x7fffc414e400) + at bgpd/bgp_routemap.c:2258 +7 0x00007f423aeec7e0 in route_map_apply_ext (map=<optimized out>, prefix=prefix@entry=0x7fffc414ea30, + match_object=match_object@entry=0x7fffc414e400, set_object=set_object@entry=0x7fffc414e400, pref=pref@entry=0x0) at lib/routemap.c:2690 +8 0x0000564dea2d277e in bgp_input_modifier (peer=peer@entry=0x7f4238f59010, p=p@entry=0x7fffc414ea30, attr=attr@entry=0x7fffc414e770, + afi=afi@entry=AFI_IP, safi=safi@entry=SAFI_UNICAST, rmap_name=rmap_name@entry=0x0, label=0x0, num_labels=0, dest=0x564debdd5130) + at bgpd/bgp_route.c:1772 +9 0x0000564dea2df762 in bgp_update (peer=peer@entry=0x7f4238f59010, p=p@entry=0x7fffc414ea30, addpath_id=addpath_id@entry=0, + attr=0x7fffc414eb50, afi=afi@entry=AFI_IP, safi=<optimized out>, safi@entry=SAFI_UNICAST, type=9, sub_type=0, prd=0x0, label=0x0, + num_labels=0, soft_reconfig=0, evpn=0x0) at bgpd/bgp_route.c:4374 +10 0x0000564dea2e2047 in bgp_nlri_parse_ip (peer=0x7f4238f59010, attr=attr@entry=0x7fffc414eb50, packet=0x7fffc414eaf0) + at bgpd/bgp_route.c:6249 +11 0x0000564dea2c5a58 in bgp_nlri_parse (peer=peer@entry=0x7f4238f59010, attr=attr@entry=0x7fffc414eb50, + packet=packet@entry=0x7fffc414eaf0, mp_withdraw=mp_withdraw@entry=false) at bgpd/bgp_packet.c:339 +12 0x0000564dea2c5d66 in bgp_update_receive (peer=peer@entry=0x7f4238f59010, size=size@entry=109) at bgpd/bgp_packet.c:2024 +13 0x0000564dea2c901d in bgp_process_packet (thread=<optimized out>) at bgpd/bgp_packet.c:2933 +14 0x00007f423af0bf71 in event_call (thread=thread@entry=0x7fffc414ee40) at lib/event.c:1995 +15 0x00007f423aebb198 in frr_run (master=0x564deb73c670) at lib/libfrr.c:1213 +16 0x0000564dea261b83 in main (argc=<optimized out>, argv=<optimized out>) at bgpd/bgp_main.c:505 +``` + +With the configuration: + +``` +frr version 9.1-dev-MyOwnFRRVersion +frr defaults traditional +hostname ip-172-31-13-140 +log file /tmp/debug.log +log syslog +service integrated-vtysh-config +! +debug bgp keepalives +debug bgp neighbor-events +debug bgp updates in +debug bgp updates out +! +router bgp 100 + bgp router-id 9.9.9.9 + no bgp ebgp-requires-policy + bgp bestpath aigp + neighbor 172.31.2.47 remote-as 200 + ! + address-family ipv4 unicast + neighbor 172.31.2.47 default-originate + neighbor 172.31.2.47 route-map RM_IN in + exit-address-family +exit +! +route-map RM_IN permit 10 + set as-path prepend 200 +exit +! +``` + +The issue is that we try to process NLRIs even if the attribute length is 0. + +Later bgp_update() will handle route-maps and a crash occurs because all the +attributes are NULL, including aspath, where we dereference. + +According to the RFC 4271: + +A value of 0 indicates that neither the Network Layer + Reachability Information field nor the Path Attribute field is + present in this UPDATE message. + +But with a fuzzed UPDATE message this can be faked. I think it's reasonable +to skip processing NLRIs if both update_len and attribute_len are 0. + +Reported-by: Iggy Frankovic <iggyfran@amazon.com> +Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org> +(cherry picked from commit 28ccc24d38df1d51ed8a563507e5d6f6171fdd38) +--- + bgpd/bgp_packet.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c +index 60f1dcbcd..a02d54894 100644 +--- a/bgpd/bgp_packet.c ++++ b/bgpd/bgp_packet.c +@@ -1983,7 +1983,7 @@ static int bgp_update_receive(struct peer *peer, bgp_size_t size) + /* Network Layer Reachability Information. */ + update_len = end - stream_pnt(s); + +- if (update_len) { ++ if (update_len && attribute_len) { + /* Set NLRI portion to structure. */ + nlris[NLRI_UPDATE].afi = AFI_IP; + nlris[NLRI_UPDATE].safi = SAFI_UNICAST; +-- +2.39.2 + |