package/polkit: backport upstream patch to fix CVE-2021-4034

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Marek Belisko <marek.belisko@open-nandra.com>
Cc: Adam Duskett <aduskett@gmail.com>
Cc: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/polkit/0004-pkexec-local-privilege-escalation-CVE-2021-4034.patch

@@ -0,0 +1,80 @@
+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)
+
+Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
+---
+ 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)
+     {
+-- 
+2.25.1
+

package/polkit/polkit.mk

@@ -12,6 +12,9 @@ POLKIT_CPE_ID_VENDOR = polkit_project
 POLKIT_AUTORECONF = YES
 POLKIT_INSTALL_STAGING = YES
 
+# 0004-pkexec-local-privilege-escalation-CVE-2021-4034.patch
+POLKIT_IGNORE_CVE = CVE-2021-4034
+
 POLKIT_DEPENDENCIES = \
 	libglib2 host-intltool expat spidermonkey $(TARGET_NLS_DEPENDENCIES)