From 0998b38e4d61179441f90dd7e7fd6a3a8b7bd8c5 Mon Sep 17 00:00:00 2001
From: Donatas Abraitis <donatas@opensourcerouting.org>
Date: Wed, 31 Jul 2024 05:56:14 +0000
Subject: [PATCH] bgpd: Check the actual remaining stream length before taking
 TLV value ```

    0 0xb50b9f898028 in __sanitizer_print_stack_trace (/home/
ubuntu/frr-public/frr_public_private-libfuzzer/bgpd/.libs/
bgpd+0x368028) (BuildId: 3292703ed7958b20076550c967f879db8dc27ca7)
    1 0xb50b9f7ed8e4 in fuzzer::PrintStackTrace() (/home/ubuntu/
frr-public/frr_public_private-libfuzzer/bgpd/.libs/bgpd+0x2bd8e4)
(BuildId: 3292703ed7958b20076550c967f879db8dc27ca7)
    2 0xb50b9f7d4d9c in fuzzer::Fuzzer::CrashCallback() (/home/
ubuntu/frr-public/frr_public_private-libfuzzer/bgpd/.libs/
bgpd+0x2a4d9c) (BuildId: 3292703ed7958b20076550c967f879db8dc27ca7)
    3 0xe0d12d7469cc  (linux-vdso.so.1+0x9cc) (BuildId:
1a77697e9d723fe22246cfd7641b140c427b7e11)
    4 0xe0d12c88f1fc in __pthread_kill_implementation nptl/
pthread_kill.c:43:17
    5 0xe0d12c84a678 in gsignal signal/../sysdeps/posix/raise.c:26:13
    6 0xe0d12c83712c in abort stdlib/abort.c:79:7
    7 0xe0d12d214724 in _zlog_assert_failed /home/ubuntu/frr-public/
frr_public_private-libfuzzer/lib/zlog.c:789:2
    8 0xe0d12d1285e4 in stream_get /home/ubuntu/frr-public/
frr_public_private-libfuzzer/lib/stream.c:324:3
    9 0xb50b9f8e47c4 in bgp_attr_encap /home/ubuntu/frr-public/
frr_public_private-libfuzzer/bgpd/bgp_attr.c:2758:3
    10 0xb50b9f8dcd38 in bgp_attr_parse /home/ubuntu/frr-public/
frr_public_private-libfuzzer/bgpd/bgp_attr.c:3783:10
    11 0xb50b9faf74b4 in bgp_update_receive /home/ubuntu/frr-public/
frr_public_private-libfuzzer/bgpd/bgp_packet.c:2383:20
    12 0xb50b9faf1dcc in bgp_process_packet /home/ubuntu/frr-public/
frr_public_private-libfuzzer/bgpd/bgp_packet.c:4075:11
    13 0xb50b9f8c90d0 in LLVMFuzzerTestOneInput /home/ubuntu/frr-public/
frr_public_private-libfuzzer/bgpd/bgp_main.c:582:3
```

Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

CVE: CVE-2024-44070
Upstream-Status: Backport [https://github.com/FRRouting/frr/commit/0998b38e4d61179441f90dd7e7fd6a3a8b7bd8c5]

Signed-off-by: Yogita Urade <yogita.urade@windriver.com>
---
 bgpd/bgp_attr.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 1e08a218e..ef45d5c46 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -2475,6 +2475,14 @@ static int bgp_attr_encap(struct bgp_attr_parser_args *args)
						  args->total);
		}

+		if (STREAM_READABLE(BGP_INPUT(peer)) < sublength) {
+			zlog_err("Tunnel Encap attribute sub-tlv length %d exceeds remaining stream length %zu",
+				 sublength, STREAM_READABLE(BGP_INPUT(peer)));
+			return bgp_attr_malformed(args,
+						  BGP_NOTIFY_UPDATE_OPT_ATTR_ERR,
+						  args->total);
+		}
+
		/* alloc and copy sub-tlv */
		/* TBD make sure these are freed when attributes are released */
		tlv = XCALLOC(MTYPE_ENCAP_TLV,
--
2.40.0
