Fix for CVE-2021-4034

This commit is contained in:
Timothée Ravier 2022-01-26 14:16:14 +01:00
parent c163eab91e
commit 96f4e91c93
2 changed files with 85 additions and 1 deletions

View File

@ -0,0 +1,79 @@
From a2bf5c9c83b6ae46cbd5c779d3055bff81ded683 Mon Sep 17 00:00:00 2001
From: Jan Rybar <jrybar@redhat.com>
Date: Tue, 25 Jan 2022 17:21:46 +0000
Subject: [PATCH] pkexec: local privilege escalation (CVE-2021-4034)
---
src/programs/pkcheck.c | 5 +++++
src/programs/pkexec.c | 23 ++++++++++++++++++++---
2 files changed, 25 insertions(+), 3 deletions(-)
diff --git a/src/programs/pkcheck.c b/src/programs/pkcheck.c
index f1bb4e1..768525c 100644
--- a/src/programs/pkcheck.c
+++ b/src/programs/pkcheck.c
@@ -363,6 +363,11 @@ main (int argc, char *argv[])
local_agent_handle = NULL;
ret = 126;
+ if (argc < 1)
+ {
+ exit(126);
+ }
+
/* Disable remote file access from GIO. */
setenv ("GIO_USE_VFS", "local", 1);
diff --git a/src/programs/pkexec.c b/src/programs/pkexec.c
index 7698c5c..84e5ef6 100644
--- a/src/programs/pkexec.c
+++ b/src/programs/pkexec.c
@@ -488,6 +488,15 @@ main (int argc, char *argv[])
pid_t pid_of_caller;
gpointer local_agent_handle;
+
+ /*
+ * If 'pkexec' is called THIS wrong, someone's probably evil-doing. Don't be nice, just bail out.
+ */
+ if (argc<1)
+ {
+ exit(127);
+ }
+
ret = 127;
authority = NULL;
subject = NULL;
@@ -614,10 +623,10 @@ main (int argc, char *argv[])
path = g_strdup (pwstruct.pw_shell);
if (!path)
- {
+ {
g_printerr ("No shell configured or error retrieving pw_shell\n");
goto out;
- }
+ }
/* If you change this, be sure to change the if (!command_line)
case below too */
command_line = g_strdup (path);
@@ -636,7 +645,15 @@ main (int argc, char *argv[])
goto out;
}
g_free (path);
- argv[n] = path = s;
+ path = s;
+
+ /* argc<2 and pkexec runs just shell, argv is guaranteed to be null-terminated.
+ * /-less shell shouldn't happen, but let's be defensive and don't write to null-termination
+ */
+ if (argv[n] != NULL)
+ {
+ argv[n] = path;
+ }
}
if (access (path, F_OK) != 0)
{
--
GitLab

View File

@ -6,12 +6,14 @@
Summary: An authorization framework Summary: An authorization framework
Name: polkit Name: polkit
Version: 0.120 Version: 0.120
Release: 2%{?dist} Release: 3%{?dist}
License: LGPLv2+ License: LGPLv2+
URL: http://www.freedesktop.org/wiki/Software/polkit URL: http://www.freedesktop.org/wiki/Software/polkit
Source0: http://www.freedesktop.org/software/polkit/releases/%{name}-%{version}.tar.gz Source0: http://www.freedesktop.org/software/polkit/releases/%{name}-%{version}.tar.gz
Source1: http://www.freedesktop.org/software/polkit/releases/%{name}-%{version}.tar.gz.sign Source1: http://www.freedesktop.org/software/polkit/releases/%{name}-%{version}.tar.gz.sign
Patch1: a2bf5c9c83b6ae46cbd5c779d3055bff81ded683.patch
BuildRequires: gcc-c++ BuildRequires: gcc-c++
BuildRequires: glib2-devel >= 2.30.0 BuildRequires: glib2-devel >= 2.30.0
BuildRequires: expat-devel BuildRequires: expat-devel
@ -174,6 +176,9 @@ exit 0
%{_libdir}/girepository-1.0/*.typelib %{_libdir}/girepository-1.0/*.typelib
%changelog %changelog
* Wed Jan 26 2022 Timothée Ravier <tim@siosm.fr> - 0.120-3
- Fix for CVE-2021-4034
* Fri Jan 21 2022 Fedora Release Engineering <releng@fedoraproject.org> - 0.120-2 * Fri Jan 21 2022 Fedora Release Engineering <releng@fedoraproject.org> - 0.120-2
- Rebuilt for https://fedoraproject.org/wiki/Fedora_36_Mass_Rebuild - Rebuilt for https://fedoraproject.org/wiki/Fedora_36_Mass_Rebuild