From ab70eee423cce4a06103f52cb4a2e3bd2740afa2 Mon Sep 17 00:00:00 2001 From: Donatas Abraitis Date: Wed, 31 Jul 2024 08:35:14 +0300 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 Signed-off-by: Donatas Abraitis (cherry picked from commit 0998b38e4d61179441f90dd7e7fd6a3a8b7bd8c5) --- bgpd/bgp_attr.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c index 0023a0176826..889902efcb0a 100644 --- a/bgpd/bgp_attr.c +++ b/bgpd/bgp_attr.c @@ -2687,6 +2687,14 @@ 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,