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- tcpslice: use-after-free in extract_slice()

This commit is contained in:
eabdullin 2024-02-12 11:39:50 +03:00
parent d31a35f316
commit 1b2c7b7502
2 changed files with 56 additions and 1 deletions
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48
SOURCES/0017-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-1.3/tcpslice.c b/tcpslice-1.3/tcpslice.c
index e7b9ba8..507dd1b 100644
--- a/tcpslice-1.3/tcpslice.c
+++ b/tcpslice-1.3/tcpslice.c
@@ -838,6 +838,13 @@ extract_slice(struct state *states, int numfiles, const char *write_file_name,
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. */
+ global_dumper = pcap_dump_open(states[0].p, write_file_name);
+ if (!global_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];
@@ -876,12 +883,6 @@ extract_slice(struct state *states, int numfiles, const char *write_file_name,
get_next_packet(s);
}
- global_dumper = pcap_dump_open(states->p, write_file_name);
- if (!global_dumper) {
- error( "error creating output file %s: %s",
- write_file_name, pcap_geterr( states->p ) );
- }
-
/*
* Now, loop thru all the packets in all the files,

9
SPECS/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: 3%{?dist}
Release: 3%{?dist}.1.alma.1
License: BSD with advertising
URL: http://www.tcpdump.org
Group: Applications/Internet
@ -27,6 +27,10 @@ Patch0014: 0014-enhance-mptcp.patch
Patch0015: 0015-CVE-2020-8037.patch
Patch0016: 0016-direction-for-any.patch
# Patches were taken from:
# https://gitlab.com/redhat/centos-stream/rpms/tcpdump/-/commit/aefd74dff4685a47468cd619ee6c88d282ce298a
Patch0017: 0017-CVE-2021-41043.patch
%define tcpslice_dir tcpslice-1.2a3
%description
@ -91,6 +95,9 @@ exit 0
%{_mandir}/man8/tcpdump.8*
%changelog
* Mon Feb 12 2024 Eduard Abdullin <eabdullin@almalinux.org> - 14:4.9.3-3.1.alma.1
- tcpslice: use-after-free in extract_slice()
* Mon Jan 10 2022 Michal Ruprich <mruprich@redhat.com> - 14:4.9.3-3
- Resolves: #2005451 - tcpdump support for direction and interface needed in RHEL8