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Resolves: RHEL-7858 - tcpslice: use-after-free in extract_slice()

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Michal Ruprich 2024-01-05 13:00:18 +01:00
parent 09efe12c8e
commit e13a9bf2e7
2 changed files with 53 additions and 1 deletions
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48
0019-CVE-2021-41043.patch Normal file
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@ -0,0 +1,48 @@
From 030859fce9c77417de657b9bb29c0f78c2d68f4a Mon Sep 17 00:00:00 2001
From: Denis Ovsienko <denis@ovsienko.info>
Date: Thu, 30 Dec 2021 17:52:52 +0000
Subject: [PATCH] CVE-2021-41043: Fix a use-after-free in extract_slice().
This issue was discovered by Mohammad Hosein Askari (@C0NSTANTINE110),
see GitHub issue #11.
In extract_slice() pcap_dump_open() takes a pcap_t argument to tell
which DLT to use for the output file. This used to be the pcap_t of the
first input file, as main() requires at least one input file. However,
the loop before pcap_dump_open() closes all, including the first, input
files that don't meet a test condition. This way, when the first file
didn't meet the condition, the call to pcap_dump_open() would end up as
a use-after-free. Make the pcap_dump_open() call before the loop, when
the first array element is always valid, and fix this problem.
---
diff --git a/tcpslice-1.2a3/tcpslice.c b/tcpslice-1.2a3/tcpslice.c
index 6d08473..7c0f4a0 100644
--- a/tcpslice-1.2a3/tcpslice.c
+++ b/tcpslice-1.2a3/tcpslice.c
@@ -841,6 +841,13 @@ extract_slice(struct state *states, const int numfiles, const char *write_file_n
TV_SUB(start_time, base_time, &relative_start);
TV_SUB(stop_time, base_time, &relative_stop);
+ /* Always write the output file, use the first input file's DLT. */
+ dumper = pcap_dump_open(states[0].p, write_file_name);
+ if (!dumper) {
+ error("error creating output file '%s': %s",
+ write_file_name, pcap_geterr(states[0].p));
+ }
+
for (i = 0; i < numfiles; ++i) {
s = &states[i];
@@ -879,12 +886,6 @@ extract_slice(struct state *states, const int numfiles, const char *write_file_n
get_next_packet(s);
}
- dumper = pcap_dump_open(states->p, write_file_name);
- if (! dumper) {
- error( "error creating output file %s: ",
- write_file_name, pcap_geterr( states->p ) );
- }
-
/*
* Now, loop thru all the packets in all the files,

6
tcpdump.spec
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@ -2,7 +2,7 @@ Summary: A network traffic monitoring tool
Name: tcpdump
Epoch: 14
Version: 4.9.3
Release: 4%{?dist}
Release: 5%{?dist}
License: BSD with advertising
URL: http://www.tcpdump.org
Group: Applications/Internet
@ -28,6 +28,7 @@ Patch0015: 0015-CVE-2020-8037.patch
Patch0016: 0016-direction-for-any.patch
Patch0017: 0017-pgm-fix-the-way-we-step-through-the-packet.patch
Patch0018: 0018-pgm-don-t-advance-bp-by-the-option-haeder-length-twi.patch
Patch0019: 0019-CVE-2021-41043.patch
%define tcpslice_dir tcpslice-1.2a3
@ -93,6 +94,9 @@ exit 0
%{_mandir}/man8/tcpdump.8*
%changelog
* Fri Jan 05 2024 Michal Ruprich <mruprich@redhat.com> - 14:4.9.3-5
- Resolves: RHEL-7858 - tcpslice: use-after-free in extract_slice()
* Wed Nov 01 2023 Pavol Žáčik <pzacik@redhat.com> - 14:4.9.3-4
- Resolves: RHEL-10708 - Fix PGM option printing