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Author SHA1 Message Date
Jan Rybar 2934e1b290 file descriptor exhaustion (GHSL-2021-077)
Resolves: CVE-2021-4115
2022-02-16 18:05:50 +01:00
Jan Rybar 1580f77437 pkexec: argv overflow results in local privilege esc.
Resolves: CVE-2021-4034
2022-01-25 19:27:51 +01:00
Jan Rybar 885883baa0 CVE-2021-3560 mitigation
Resolves: CVE-2021-3560
2021-06-03 14:21:55 +02:00
4 changed files with 179 additions and 1 deletions

13
CVE-2021-3560.patch Normal file
View File

@ -0,0 +1,13 @@
--- a/src/polkit/polkitsystembusname.c
+++ b/src/polkit/polkitsystembusname.c
@@ -435,6 +435,9 @@ polkit_system_bus_name_get_creds_sync (PolkitSystemBusName *system_bus
while (!((data.retrieved_uid && data.retrieved_pid) || data.caught_error))
g_main_context_iteration (tmp_context, TRUE);
+ if (data.caught_error)
+ goto out;
+
if (out_uid)
*out_uid = data.uid;
if (out_pid)

79
CVE-2021-4034.patch Normal file
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@ -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)
{
--
2.31.1

71
CVE-2021-4115.patch Normal file
View File

@ -0,0 +1,71 @@
diff --git a/src/polkit/polkitsystembusname.c b/src/polkit/polkitsystembusname.c
index 8ed1363..2fbf5f1 100644
--- a/src/polkit/polkitsystembusname.c
+++ b/src/polkit/polkitsystembusname.c
@@ -62,6 +62,10 @@ enum
PROP_NAME,
};
+
+guint8 dbus_call_respond_fails; // has to be global because of callback
+
+
static void subject_iface_init (PolkitSubjectIface *subject_iface);
G_DEFINE_TYPE_WITH_CODE (PolkitSystemBusName, polkit_system_bus_name, G_TYPE_OBJECT,
@@ -364,6 +368,7 @@ on_retrieved_unix_uid_pid (GObject *src,
if (!v)
{
data->caught_error = TRUE;
+ dbus_call_respond_fails += 1;
}
else
{
@@ -405,6 +410,8 @@ polkit_system_bus_name_get_creds_sync (PolkitSystemBusName *system_bus
tmp_context = g_main_context_new ();
g_main_context_push_thread_default (tmp_context);
+ dbus_call_respond_fails = 0;
+
/* Do two async calls as it's basically as fast as one sync call.
*/
g_dbus_connection_call (connection,
@@ -432,11 +439,34 @@ polkit_system_bus_name_get_creds_sync (PolkitSystemBusName *system_bus
on_retrieved_unix_uid_pid,
&data);
- while (!((data.retrieved_uid && data.retrieved_pid) || data.caught_error))
- g_main_context_iteration (tmp_context, TRUE);
+ while (TRUE)
+ {
+ /* If one dbus call returns error, we must wait until the other call
+ * calls _call_finish(), otherwise fd leak is possible.
+ * Resolves: GHSL-2021-077
+ */
- if (data.caught_error)
- goto out;
+ if ( (dbus_call_respond_fails > 1) )
+ {
+ // we got two faults, we can leave
+ goto out;
+ }
+
+ if ((data.caught_error && (data.retrieved_pid || data.retrieved_uid)))
+ {
+ // we got one fault and the other call finally finished, we can leave
+ goto out;
+ }
+
+ if ( !(data.retrieved_uid && data.retrieved_pid) )
+ {
+ g_main_context_iteration (tmp_context, TRUE);
+ }
+ else
+ {
+ break;
+ }
+ }
if (out_uid)
*out_uid = data.uid;

View File

@ -6,13 +6,16 @@
Summary: An authorization framework
Name: polkit
Version: 0.117
Release: 3%{?dist}
Release: 3%{?dist}.3
License: LGPLv2+
URL: http://www.freedesktop.org/wiki/Software/polkit
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
Patch1: mozjs78.patch
Patch2: CVE-2021-3560.patch
Patch3: CVE-2021-4034.patch
Patch4: CVE-2021-4115.patch
BuildRequires: make
BuildRequires: gcc-c++
@ -177,6 +180,18 @@ exit 0
%{_libdir}/girepository-1.0/*.typelib
%changelog
* Wed Feb 16 2022 Jan Rybar <jrybar@redhat.com> - 0.117-3.3
- file descriptor exhaustion (GHSL-2021-077)
- Resolves: CVE-2021-4115
* Tue Jan 25 2022 Jan Rybar <jrybar@redhat.com> - 0.117-3.2
- pkexec: argv overflow results in local privilege esc.
- Resolves: CVE-2021-4034
* Thu May 20 2021 Jan Rybar <jrybar@redhat.com> - 0.117-3.1
- CVE-2021-3560 mitigation
- Resolves: CVE-2021-3560
* Wed Jan 27 2021 Fedora Release Engineering <releng@fedoraproject.org> - 0.117-3
- Rebuilt for https://fedoraproject.org/wiki/Fedora_34_Mass_Rebuild