path: root/extra/polkit/polkit-101-CVE-2011-1485.patch

From dd848a42a64a3b22a0cc60f6657b56ce9b6010ae Mon Sep 17 00:00:00 2001
From: David Zeuthen <davidz@redhat.com>
Date: Thu, 31 Mar 2011 16:59:09 +0000
Subject: PolkitUnixProcess: Clarify that the real uid is returned, not the effective one

On Linux, also switch to parsing /proc/<pid>/status instead of relying
on the st_uid returned by stat(2) to be the uid we want.

This was pointed out by Neel Mehta <nmehta@google.com>. Thanks!

Signed-off-by: David Zeuthen <davidz@redhat.com>
---
diff --git a/src/polkit/polkitunixprocess.c b/src/polkit/polkitunixprocess.c
index d95a1d4..876da69 100644
--- a/src/polkit/polkitunixprocess.c
+++ b/src/polkit/polkitunixprocess.c
@@ -24,9 +24,7 @@
 #endif
 
 #include <sys/types.h>
-#ifndef HAVE_FREEBSD
-#include <sys/stat.h>
-#else
+#ifdef HAVE_FREEBSD
 #include <sys/param.h>
 #include <sys/sysctl.h>
 #include <sys/user.h>
@@ -34,6 +32,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <stdio.h>
 
 #include "polkitunixprocess.h"
 #include "polkitsubject.h"
@@ -208,6 +207,8 @@ polkit_unix_process_get_pid (PolkitUnixProcess *process)
  *
  * Gets the uid of the owner of @process.
  *
+ * Note that this returns the real user-id (not the effective user-id) of @process.
+ *
  * Returns: The UNIX user id of the owner for @process or 0 if @error is set.
  **/
 gint
@@ -215,17 +216,21 @@ polkit_unix_process_get_owner (PolkitUnixProcess  *process,
                                GError            **error)
 {
   gint result;
+  gchar *contents;
+  gchar **lines;
 #ifdef HAVE_FREEBSD
   struct kinfo_proc p;
 #else
-  struct stat statbuf;
-  char procbuf[32];
+  gchar filename[64];
+  guint n;
 #endif
 
   g_return_val_if_fail (POLKIT_IS_UNIX_PROCESS (process), 0);
   g_return_val_if_fail (error == NULL || *error == NULL, 0);
 
   result = 0;
+  lines = NULL;
+  contents = NULL;
 
 #ifdef HAVE_FREEBSD
   if (get_kinfo_proc (process->pid, &p) == 0)
@@ -241,23 +246,52 @@ polkit_unix_process_get_owner (PolkitUnixProcess  *process,
 
   result = p.ki_uid;
 #else
-  g_snprintf (procbuf, sizeof procbuf, "/proc/%d", process->pid);
-  if (stat (procbuf, &statbuf) != 0)
+
+  /* see 'man proc' for layout of the status file
+   *
+   * Uid, Gid: Real, effective, saved set,  and  file  system  UIDs (GIDs).
+   */
+  g_snprintf (filename, sizeof filename, "/proc/%d/status", process->pid);
+  if (!g_file_get_contents (filename,
+                            &contents,
+                            NULL,
+                            error))
     {
-      g_set_error (error,
-                   POLKIT_ERROR,
-                   POLKIT_ERROR_FAILED,
-                   "stat() failed for /proc/%d: %s",
-                   process->pid,
-                   g_strerror (errno));
       goto out;
     }
+  lines = g_strsplit (contents, "\n", -1);
+  for (n = 0; lines != NULL && lines[n] != NULL; n++)
+    {
+      gint real_uid, effective_uid;
+      if (!g_str_has_prefix (lines[n], "Uid:"))
+        continue;
+      if (sscanf (lines[n] + 4, "%d %d", &real_uid, &effective_uid) != 2)
+        {
+          g_set_error (error,
+                       POLKIT_ERROR,
+                       POLKIT_ERROR_FAILED,
+                       "Unexpected line `%s' in file %s",
+                       lines[n],
+                       filename);
+          goto out;
+        }
+      else
+        {
+          result = real_uid;
+          goto out;
+        }
+    }
 
-  result = statbuf.st_uid;
+  g_set_error (error,
+               POLKIT_ERROR,
+               POLKIT_ERROR_FAILED,
+               "Didn't find any line starting with `Uid:' in file %s",
+               filename);
 #endif
 
- out:
-
+out:
+  g_strfreev (lines);
+  g_free (contents);
   return result;
 }
 
--
cgit v0.8.3-6-g21f6
From 129b6223a19e7fb2753f8cad7957ac5402394076 Mon Sep 17 00:00:00 2001
From: David Zeuthen <davidz@redhat.com>
Date: Fri, 01 Apr 2011 16:09:45 +0000
Subject: Make PolkitUnixProcess also record the uid of the process

This is needed to avoid possible TOCTTOU issues since a process can
change both its real uid and effective uid.

Signed-off-by: David Zeuthen <davidz@redhat.com>
---
diff --git a/docs/polkit/polkit-1-sections.txt b/docs/polkit/polkit-1-sections.txt
index 12141e3..9f4fcf8 100644
--- a/docs/polkit/polkit-1-sections.txt
+++ b/docs/polkit/polkit-1-sections.txt
@@ -145,10 +145,13 @@ POLKIT_UNIX_SESSION_GET_CLASS
 PolkitUnixProcess
 polkit_unix_process_new
 polkit_unix_process_new_full
+polkit_unix_process_new_for_owner
+polkit_unix_process_set_pid
 polkit_unix_process_get_pid
+polkit_unix_process_set_start_time
 polkit_unix_process_get_start_time
-polkit_unix_process_set_pid
-polkit_unix_process_get_owner
+polkit_unix_process_set_uid
+polkit_unix_process_get_uid
 <SUBSECTION Standard>
 PolkitUnixProcessClass
 POLKIT_UNIX_PROCESS
diff --git a/src/polkit/polkitsubject.c b/src/polkit/polkitsubject.c
index 577afec..d2c4c20 100644
--- a/src/polkit/polkitsubject.c
+++ b/src/polkit/polkitsubject.c
@@ -238,13 +238,18 @@ polkit_subject_from_string  (const gchar   *str,
     {
       gint scanned_pid;
       guint64 scanned_starttime;
-      if (sscanf (str, "unix-process:%d:%" G_GUINT64_FORMAT, &scanned_pid, &scanned_starttime) == 2)
+      gint scanned_uid;
+      if (sscanf (str, "unix-process:%d:%" G_GUINT64_FORMAT ":%d", &scanned_pid, &scanned_starttime, &scanned_uid) == 3)
+        {
+          subject = polkit_unix_process_new_for_owner (scanned_pid, scanned_starttime, scanned_uid);
+        }
+      else if (sscanf (str, "unix-process:%d:%" G_GUINT64_FORMAT, &scanned_pid, &scanned_starttime) == 2)
         {
           subject = polkit_unix_process_new_full (scanned_pid, scanned_starttime);
         }
       else if (sscanf (str, "unix-process:%d", &scanned_pid) == 1)
         {
-          subject = polkit_unix_process_new_full (scanned_pid, 0);
+          subject = polkit_unix_process_new (scanned_pid);
           if (polkit_unix_process_get_start_time (POLKIT_UNIX_PROCESS (subject)) == 0)
             {
               g_object_unref (subject);
@@ -297,6 +302,8 @@ polkit_subject_to_gvariant (PolkitSubject *subject)
                              g_variant_new_uint32 (polkit_unix_process_get_pid (POLKIT_UNIX_PROCESS (subject))));
       g_variant_builder_add (&builder, "{sv}", "start-time",
                              g_variant_new_uint64 (polkit_unix_process_get_start_time (POLKIT_UNIX_PROCESS (subject))));
+      g_variant_builder_add (&builder, "{sv}", "uid",
+                             g_variant_new_int32 (polkit_unix_process_get_uid (POLKIT_UNIX_PROCESS (subject))));
     }
   else if (POLKIT_IS_UNIX_SESSION (subject))
     {
@@ -395,6 +402,7 @@ polkit_subject_new_for_gvariant (GVariant  *variant,
       GVariant *v;
       guint32 pid;
       guint64 start_time;
+      gint32 uid;
 
       v = lookup_asv (details_gvariant, "pid", G_VARIANT_TYPE_UINT32, error);
       if (v == NULL)
@@ -414,7 +422,18 @@ polkit_subject_new_for_gvariant (GVariant  *variant,
       start_time = g_variant_get_uint64 (v);
       g_variant_unref (v);
 
-      ret = polkit_unix_process_new_full (pid, start_time);
+      v = lookup_asv (details_gvariant, "uid", G_VARIANT_TYPE_INT32, error);
+      if (v != NULL)
+        {
+          uid = g_variant_get_int32 (v);
+          g_variant_unref (v);
+        }
+      else
+        {
+          uid = -1;
+        }
+
+      ret = polkit_unix_process_new_for_owner (pid, start_time, uid);
     }
   else if (g_strcmp0 (kind, "unix-session") == 0)
     {
diff --git a/src/polkit/polkitunixprocess.c b/src/polkit/polkitunixprocess.c
index 876da69..913be3a 100644
--- a/src/polkit/polkitunixprocess.c
+++ b/src/polkit/polkitunixprocess.c
@@ -62,6 +62,7 @@ struct _PolkitUnixProcess
 
   gint pid;
   guint64 start_time;
+  gint uid;
 };
 
 struct _PolkitUnixProcessClass
@@ -74,6 +75,7 @@ enum
   PROP_0,
   PROP_PID,
   PROP_START_TIME,
+  PROP_UID
 };
 
 static void subject_iface_init (PolkitSubjectIface *subject_iface);
@@ -81,6 +83,9 @@ static void subject_iface_init (PolkitSubjectIface *subject_iface);
 static guint64 get_start_time_for_pid (gint    pid,
                                        GError **error);
 
+static gint _polkit_unix_process_get_owner (PolkitUnixProcess  *process,
+                                            GError            **error);
+
 #ifdef HAVE_FREEBSD
 static gboolean get_kinfo_proc (gint pid, struct kinfo_proc *p);
 #endif
@@ -92,6 +97,7 @@ G_DEFINE_TYPE_WITH_CODE (PolkitUnixProcess, polkit_unix_process, G_TYPE_OBJECT,
 static void
 polkit_unix_process_init (PolkitUnixProcess *unix_process)
 {
+  unix_process->uid = -1;
 }
 
 static void
@@ -108,6 +114,10 @@ polkit_unix_process_get_property (GObject    *object,
       g_value_set_int (value, unix_process->pid);
       break;
 
+    case PROP_UID:
+      g_value_set_int (value, unix_process->uid);
+      break;
+
     case PROP_START_TIME:
       g_value_set_uint64 (value, unix_process->start_time);
       break;
@@ -132,6 +142,14 @@ polkit_unix_process_set_property (GObject      *object,
       polkit_unix_process_set_pid (unix_process, g_value_get_int (value));
       break;
 
+    case PROP_UID:
+      polkit_unix_process_set_uid (unix_process, g_value_get_int (value));
+      break;
+
+    case PROP_START_TIME:
+      polkit_unix_process_set_start_time (unix_process, g_value_get_uint64 (value));
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -139,12 +157,39 @@ polkit_unix_process_set_property (GObject      *object,
 }
 
 static void
+polkit_unix_process_constructed (GObject *object)
+{
+  PolkitUnixProcess *process = POLKIT_UNIX_PROCESS (object);
+
+  /* sets start_time and uid in case they are unset */
+
+  if (process->start_time == 0)
+    process->start_time = get_start_time_for_pid (process->pid, NULL);
+
+  if (process->uid == -1)
+    {
+      GError *error;
+      error = NULL;
+      process->uid = _polkit_unix_process_get_owner (process, &error);
+      if (error != NULL)
+        {
+          process->uid = -1;
+          g_error_free (error);
+        }
+    }
+
+  if (G_OBJECT_CLASS (polkit_unix_process_parent_class)->constructed != NULL)
+    G_OBJECT_CLASS (polkit_unix_process_parent_class)->constructed (object);
+}
+
+static void
 polkit_unix_process_class_init (PolkitUnixProcessClass *klass)
 {
   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 
   gobject_class->get_property = polkit_unix_process_get_property;
   gobject_class->set_property = polkit_unix_process_set_property;
+  gobject_class->constructed =  polkit_unix_process_constructed;
 
   /**
    * PolkitUnixProcess:pid:
@@ -156,7 +201,7 @@ polkit_unix_process_class_init (PolkitUnixProcessClass *klass)
                                    g_param_spec_int ("pid",
                                                      "Process ID",
                                                      "The UNIX process ID",
-                                                     -1,
+                                                     0,
                                                      G_MAXINT,
                                                      0,
                                                      G_PARAM_CONSTRUCT |
@@ -166,6 +211,27 @@ polkit_unix_process_class_init (PolkitUnixProcessClass *klass)
                                                      G_PARAM_STATIC_NICK));
 
   /**
+   * PolkitUnixProcess:uid:
+   *
+   * The UNIX user id of the process or -1 if unknown.
+   *
+   * Note that this is the real user-id, not the effective user-id.
+   */
+  g_object_class_install_property (gobject_class,
+                                   PROP_UID,
+                                   g_param_spec_int ("uid",
+                                                     "User ID",
+                                                     "The UNIX user ID",
+                                                     -1,
+                                                     G_MAXINT,
+                                                     -1,
+                                                     G_PARAM_CONSTRUCT |
+                                                     G_PARAM_READWRITE |
+                                                     G_PARAM_STATIC_NAME |
+                                                     G_PARAM_STATIC_BLURB |
+                                                     G_PARAM_STATIC_NICK));
+
+  /**
    * PolkitUnixProcess:start-time:
    *
    * The start time of the process.
@@ -178,7 +244,8 @@ polkit_unix_process_class_init (PolkitUnixProcessClass *klass)
                                                         0,
                                                         G_MAXUINT64,
                                                         0,
-                                                        G_PARAM_READABLE |
+                                                        G_PARAM_CONSTRUCT |
+                                                        G_PARAM_READWRITE |
                                                         G_PARAM_STATIC_NAME |
                                                         G_PARAM_STATIC_BLURB |
                                                         G_PARAM_STATIC_NICK));
@@ -186,113 +253,50 @@ polkit_unix_process_class_init (PolkitUnixProcessClass *klass)
 }
 
 /**
- * polkit_unix_process_get_pid:
+ * polkit_unix_process_get_uid:
  * @process: A #PolkitUnixProcess.
  *
- * Gets the process id for @process.
+ * Gets the user id for @process. Note that this is the real user-id,
+ * not the effective user-id.
  *
- * Returns: The process id for @process.
+ * Returns: The user id for @process or -1 if unknown.
  */
 gint
-polkit_unix_process_get_pid (PolkitUnixProcess *process)
+polkit_unix_process_get_uid (PolkitUnixProcess *process)
 {
-  g_return_val_if_fail (POLKIT_IS_UNIX_PROCESS (process), 0);
-  return process->pid;
+  g_return_val_if_fail (POLKIT_IS_UNIX_PROCESS (process), -1);
+  return process->uid;
 }
 
 /**
- * polkit_unix_process_get_owner:
+ * polkit_unix_process_set_uid:
  * @process: A #PolkitUnixProcess.
- * @error: (allow-none): Return location for error or %NULL.
+ * @uid: The user id to set for @process or -1 to unset it.
  *
- * Gets the uid of the owner of @process.
+ * Sets the (real, not effective) user id for @process.
+ */
+void
+polkit_unix_process_set_uid (PolkitUnixProcess *process,
+                             gint               uid)
+{
+  g_return_if_fail (POLKIT_IS_UNIX_PROCESS (process));
+  g_return_if_fail (uid >= -1);
+  process->uid = uid;
+}
+
+/**
+ * polkit_unix_process_get_pid:
+ * @process: A #PolkitUnixProcess.
  *
- * Note that this returns the real user-id (not the effective user-id) of @process.
+ * Gets the process id for @process.
  *
- * Returns: The UNIX user id of the owner for @process or 0 if @error is set.
- **/
+ * Returns: The process id for @process.
+ */
 gint
-polkit_unix_process_get_owner (PolkitUnixProcess  *process,
-                               GError            **error)
+polkit_unix_process_get_pid (PolkitUnixProcess *process)
 {
-  gint result;
-  gchar *contents;
-  gchar **lines;
-#ifdef HAVE_FREEBSD
-  struct kinfo_proc p;
-#else
-  gchar filename[64];
-  guint n;
-#endif
-
   g_return_val_if_fail (POLKIT_IS_UNIX_PROCESS (process), 0);
-  g_return_val_if_fail (error == NULL || *error == NULL, 0);
-
-  result = 0;
-  lines = NULL;
-  contents = NULL;
-
-#ifdef HAVE_FREEBSD
-  if (get_kinfo_proc (process->pid, &p) == 0)
-    {
-      g_set_error (error,
-                   POLKIT_ERROR,
-                   POLKIT_ERROR_FAILED,
-                   "get_kinfo_proc() failed for pid %d: %s",
-                   process->pid,
-                   g_strerror (errno));
-      goto out;
-    }
-
-  result = p.ki_uid;
-#else
-
-  /* see 'man proc' for layout of the status file
-   *
-   * Uid, Gid: Real, effective, saved set,  and  file  system  UIDs (GIDs).
-   */
-  g_snprintf (filename, sizeof filename, "/proc/%d/status", process->pid);
-  if (!g_file_get_contents (filename,
-                            &contents,
-                            NULL,
-                            error))
-    {
-      goto out;
-    }
-  lines = g_strsplit (contents, "\n", -1);
-  for (n = 0; lines != NULL && lines[n] != NULL; n++)
-    {
-      gint real_uid, effective_uid;
-      if (!g_str_has_prefix (lines[n], "Uid:"))
-        continue;
-      if (sscanf (lines[n] + 4, "%d %d", &real_uid, &effective_uid) != 2)
-        {
-          g_set_error (error,
-                       POLKIT_ERROR,
-                       POLKIT_ERROR_FAILED,
-                       "Unexpected line `%s' in file %s",
-                       lines[n],
-                       filename);
-          goto out;
-        }
-      else
-        {
-          result = real_uid;
-          goto out;
-        }
-    }
-
-  g_set_error (error,
-               POLKIT_ERROR,
-               POLKIT_ERROR_FAILED,
-               "Didn't find any line starting with `Uid:' in file %s",
-               filename);
-#endif
-
-out:
-  g_strfreev (lines);
-  g_free (contents);
-  return result;
+  return process->pid;
 }
 
 /**
@@ -311,6 +315,21 @@ polkit_unix_process_get_start_time (PolkitUnixProcess *process)
 }
 
 /**
+ * polkit_unix_process_set_start_time:
+ * @process: A #PolkitUnixProcess.
+ * @start_time: The start time for @pid.
+ *
+ * Set the start time of @process.
+ */
+void
+polkit_unix_process_set_start_time (PolkitUnixProcess *process,
+                                    guint64            start_time)
+{
+  g_return_if_fail (POLKIT_IS_UNIX_PROCESS (process));
+  process->start_time = start_time;
+}
+
+/**
  * polkit_unix_process_set_pid:
  * @process: A #PolkitUnixProcess.
  * @pid: A process id.
@@ -323,18 +342,17 @@ polkit_unix_process_set_pid (PolkitUnixProcess *process,
 {
   g_return_if_fail (POLKIT_IS_UNIX_PROCESS (process));
   process->pid = pid;
-  if (pid != (gint) -1)
-    process->start_time = get_start_time_for_pid (pid, NULL);
 }
 
 /**
  * polkit_unix_process_new:
  * @pid: The process id.
  *
- * Creates a new #PolkitUnixProcess for @pid. The start time of the
- * process will be looked up in using e.g. the
- * <filename>/proc</filename> filesystem depending on the platform in
- * use.
+ * Creates a new #PolkitUnixProcess for @pid.
+ *
+ * The uid and start time of the process will be looked up in using
+ * e.g. the <filename>/proc</filename> filesystem depending on the
+ * platform in use.
  *
  * Returns: (transfer full): A #PolkitSubject. Free with g_object_unref().
  */
@@ -353,22 +371,42 @@ polkit_unix_process_new (gint pid)
  *
  * Creates a new #PolkitUnixProcess object for @pid and @start_time.
  *
+ * The uid of the process will be looked up in using e.g. the
+ * <filename>/proc</filename> filesystem depending on the platform in
+ * use.
+ *
  * Returns: (transfer full): A #PolkitSubject. Free with g_object_unref().
  */
 PolkitSubject *
 polkit_unix_process_new_full (gint pid,
                               guint64 start_time)
 {
-  PolkitUnixProcess *process;
-
-  process = POLKIT_UNIX_PROCESS (polkit_unix_process_new ((gint) -1));
-  process->pid = pid;
-  if (start_time != 0)
-    process->start_time = start_time;
-  else
-    process->start_time = get_start_time_for_pid (pid, NULL);
+  return POLKIT_SUBJECT (g_object_new (POLKIT_TYPE_UNIX_PROCESS,
+                                       "pid", pid,
+                                       "start_time", start_time,
+                                       NULL));
+}
 
-  return POLKIT_SUBJECT (process);
+/**
+ * polkit_unix_process_new_for_owner:
+ * @pid: The process id.
+ * @start_time: The start time for @pid or 0 to look it up in e.g. <filename>/proc</filename>.
+ * @uid: The (real, not effective) uid of the owner of @pid or -1 to look it up in e.g. <filename>/proc</filename>.
+ *
+ * Creates a new #PolkitUnixProcess object for @pid, @start_time and @uid.
+ *
+ * Returns: (transfer full): A #PolkitSubject. Free with g_object_unref().
+ */
+PolkitSubject *
+polkit_unix_process_new_for_owner (gint    pid,
+                                   guint64 start_time,
+                                   gint    uid)
+{
+  return POLKIT_SUBJECT (g_object_new (POLKIT_TYPE_UNIX_PROCESS,
+                                       "pid", pid,
+                                       "start_time", start_time,
+                                       "uid", uid,
+                                       NULL));
 }
 
 static guint
@@ -616,3 +654,95 @@ out:
 
   return start_time;
 }
+
+static gint
+_polkit_unix_process_get_owner (PolkitUnixProcess  *process,
+                                GError            **error)
+{
+  gint result;
+  gchar *contents;
+  gchar **lines;
+#ifdef HAVE_FREEBSD
+  struct kinfo_proc p;
+#else
+  gchar filename[64];
+  guint n;
+#endif
+
+  g_return_val_if_fail (POLKIT_IS_UNIX_PROCESS (process), 0);
+  g_return_val_if_fail (error == NULL || *error == NULL, 0);
+
+  result = 0;
+  lines = NULL;
+  contents = NULL;
+
+#ifdef HAVE_FREEBSD
+  if (get_kinfo_proc (process->pid, &p) == 0)
+    {
+      g_set_error (error,
+                   POLKIT_ERROR,
+                   POLKIT_ERROR_FAILED,
+                   "get_kinfo_proc() failed for pid %d: %s",
+                   process->pid,
+                   g_strerror (errno));
+      goto out;
+    }
+
+  result = p.ki_uid;
+#else
+
+  /* see 'man proc' for layout of the status file
+   *
+   * Uid, Gid: Real, effective, saved set,  and  file  system  UIDs (GIDs).
+   */
+  g_snprintf (filename, sizeof filename, "/proc/%d/status", process->pid);
+  if (!g_file_get_contents (filename,
+                            &contents,
+                            NULL,
+                            error))
+    {
+      goto out;
+    }
+  lines = g_strsplit (contents, "\n", -1);
+  for (n = 0; lines != NULL && lines[n] != NULL; n++)
+    {
+      gint real_uid, effective_uid;
+      if (!g_str_has_prefix (lines[n], "Uid:"))
+        continue;
+      if (sscanf (lines[n] + 4, "%d %d", &real_uid, &effective_uid) != 2)
+        {
+          g_set_error (error,
+                       POLKIT_ERROR,
+                       POLKIT_ERROR_FAILED,
+                       "Unexpected line `%s' in file %s",
+                       lines[n],
+                       filename);
+          goto out;
+        }
+      else
+        {
+          result = real_uid;
+          goto out;
+        }
+    }
+
+  g_set_error (error,
+               POLKIT_ERROR,
+               POLKIT_ERROR_FAILED,
+               "Didn't find any line starting with `Uid:' in file %s",
+               filename);
+#endif
+
+out:
+  g_strfreev (lines);
+  g_free (contents);
+  return result;
+}
+
+/* deprecated public method */
+gint
+polkit_unix_process_get_owner (PolkitUnixProcess  *process,
+                               GError            **error)
+{
+  return _polkit_unix_process_get_owner (process, error);
+}
diff --git a/src/polkit/polkitunixprocess.h b/src/polkit/polkitunixprocess.h
index b88cd03..531a57d 100644
--- a/src/polkit/polkitunixprocess.h
+++ b/src/polkit/polkitunixprocess.h
@@ -47,16 +47,24 @@ typedef struct _PolkitUnixProcess PolkitUnixProcess;
 typedef struct _PolkitUnixProcessClass PolkitUnixProcessClass;
 
 GType           polkit_unix_process_get_type       (void) G_GNUC_CONST;
-PolkitSubject  *polkit_unix_process_new            (gint pid);
-PolkitSubject  *polkit_unix_process_new_full       (gint pid,
-                                                    guint64 start_time);
-
+PolkitSubject  *polkit_unix_process_new            (gint               pid);
+PolkitSubject  *polkit_unix_process_new_full       (gint               pid,
+                                                    guint64            start_time);
+PolkitSubject  *polkit_unix_process_new_for_owner  (gint               pid,
+                                                    guint64            start_time,
+                                                    gint               uid);
 gint            polkit_unix_process_get_pid        (PolkitUnixProcess *process);
 guint64         polkit_unix_process_get_start_time (PolkitUnixProcess *process);
+gint            polkit_unix_process_get_uid        (PolkitUnixProcess *process);
 void            polkit_unix_process_set_pid        (PolkitUnixProcess *process,
                                                     gint               pid);
+void            polkit_unix_process_set_uid        (PolkitUnixProcess *process,
+                                                    gint               uid);
+void            polkit_unix_process_set_start_time (PolkitUnixProcess *process,
+                                                    guint64            start_time);
+
 gint            polkit_unix_process_get_owner      (PolkitUnixProcess  *process,
-                                                    GError            **error);
+                                                    GError            **error) G_GNUC_DEPRECATED_FOR (polkit_unix_process_get_uid);
 
 G_END_DECLS
 
--
cgit v0.8.3-6-g21f6
From c23d74447c7615dc74dae259f0fc3688ec988867 Mon Sep 17 00:00:00 2001
From: David Zeuthen <davidz@redhat.com>
Date: Fri, 01 Apr 2011 16:12:27 +0000
Subject: Use polkit_unix_process_get_uid() to get the owner of a process

This avoids a TOCTTOU problem.

Signed-off-by: David Zeuthen <davidz@redhat.com>
---
diff --git a/src/polkitbackend/polkitbackendsessionmonitor.c b/src/polkitbackend/polkitbackendsessionmonitor.c
index 495f752..9c331b6 100644
--- a/src/polkitbackend/polkitbackendsessionmonitor.c
+++ b/src/polkitbackend/polkitbackendsessionmonitor.c
@@ -293,14 +293,15 @@ polkit_backend_session_monitor_get_user_for_subject (PolkitBackendSessionMonitor
 
   if (POLKIT_IS_UNIX_PROCESS (subject))
     {
-      local_error = NULL;
-      uid = polkit_unix_process_get_owner (POLKIT_UNIX_PROCESS (subject), &local_error);
-      if (local_error != NULL)
+      uid = polkit_unix_process_get_uid (POLKIT_UNIX_PROCESS (subject));
+      if ((gint) uid == -1)
         {
-          g_propagate_prefixed_error (error, local_error, "Error getting user for process: ");
+          g_set_error (error,
+                       POLKIT_ERROR,
+                       POLKIT_ERROR_FAILED,
+                       "Unix process subject does not have uid set");
           goto out;
         }
-
       ret = polkit_unix_user_new (uid);
     }
   else if (POLKIT_IS_SYSTEM_BUS_NAME (subject))
--
cgit v0.8.3-6-g21f6
From 3b12cfac29dddd27f1f166a7574d8374cc1dccf2 Mon Sep 17 00:00:00 2001
From: David Zeuthen <davidz@redhat.com>
Date: Fri, 01 Apr 2011 16:13:15 +0000
Subject: pkexec: Avoid TOCTTOU problems with parent process

In a nutshell, the parent process may change its uid (either real- or
effective uid) after launching pkexec. It can do this by exec()'ing
e.g. a setuid root program.

To avoid this problem, just use the uid the parent process had when it
executed pkexec. This happens to be the same uid of the pkexec process
itself.

Additionally, remove some dubious code that allowed pkexec to continue
when the parent process died as there is no reason to support
something like that. Also ensure that the pkexec process is killed if
the parent process dies.

This problem was pointed out by Neel Mehta <nmehta@google.com>.

Signed-off-by: David Zeuthen <davidz@redhat.com>
---
diff --git a/src/programs/pkexec.c b/src/programs/pkexec.c
index 9217954..3e656be 100644
--- a/src/programs/pkexec.c
+++ b/src/programs/pkexec.c
@@ -35,6 +35,10 @@
 #include <pwd.h>
 #include <errno.h>
 
+#ifdef __linux__
+#include <sys/prctl.h>
+#endif
+
 #include <glib/gi18n.h>
 
 #ifdef POLKIT_AUTHFW_PAM
@@ -423,7 +427,6 @@ main (int argc, char *argv[])
   GPtrArray *saved_env;
   gchar *opt_user;
   pid_t pid_of_caller;
-  uid_t uid_of_caller;
   gpointer local_agent_handle;
 
   ret = 127;
@@ -598,40 +601,49 @@ main (int argc, char *argv[])
    */
   g_type_init ();
 
-  /* now check if the program that invoked us is authorized */
+  /* make sure we are nuked if the parent process dies */
+#ifdef __linux__
+  if (prctl (PR_SET_PDEATHSIG, SIGTERM) != 0)
+    {
+      g_printerr ("prctl(PR_SET_PDEATHSIG, SIGTERM) failed: %s\n", g_strerror (errno));
+      goto out;
+    }
+#else
+#warning "Please add OS specific code to catch when the parent dies"
+#endif
+
+  /* Figure out the parent process */
   pid_of_caller = getppid ();
   if (pid_of_caller == 1)
     {
       /* getppid() can return 1 if the parent died (meaning that we are reaped
-       * by /sbin/init); get process group leader instead - for example, this
-       * happens when launching via gnome-panel (alt+f2, then 'pkexec gedit').
+       * by /sbin/init); In that case we simpy bail.
        */
-      pid_of_caller = getpgrp ();
-    }
-
-  subject = polkit_unix_process_new (pid_of_caller);
-  if (subject == NULL)
-    {
-      g_printerr ("No such process for pid %d: %s\n", (gint) pid_of_caller, error->message);
-      g_error_free (error);
+      g_printerr ("Refusing to render service to dead parents.\n");
       goto out;
     }
 
-  /* paranoia: check that the uid of pid_of_caller matches getuid() */
-  error = NULL;
-  uid_of_caller = polkit_unix_process_get_owner (POLKIT_UNIX_PROCESS (subject),
-                                                 &error);
-  if (error != NULL)
-    {
-      g_printerr ("Error determing pid of caller (pid %d): %s\n", (gint) pid_of_caller, error->message);
-      g_error_free (error);
-      goto out;
-    }
-  if (uid_of_caller != getuid ())
-    {
-      g_printerr ("User of caller (%d) does not match our uid (%d)\n", uid_of_caller, getuid ());
-      goto out;
-    }
+  /* This process we want to check an authorization for is the process
+   * that launched us - our parent process.
+   *
+   * At the time the parent process fork()'ed and exec()'ed us, the
+   * process had the same real-uid that we have now. So we use this
+   * real-uid instead of of looking it up to avoid TOCTTOU issues
+   * (consider the parent process exec()'ing a setuid helper).
+   *
+   * On the other hand, the monotonic process start-time is guaranteed
+   * to never change so it's safe to look that up given only the PID
+   * since we are guaranteed to be nuked if the parent goes away
+   * (cf. the prctl(2) call above).
+   */
+  subject = polkit_unix_process_new_for_owner (pid_of_caller,
+                                               0, /* 0 means "look up start-time in /proc" */
+                                               getuid ());
+  /* really double-check the invariants guaranteed by the PolkitUnixProcess class */
+  g_assert (subject != NULL);
+  g_assert (polkit_unix_process_get_pid (POLKIT_UNIX_PROCESS (subject)) == pid_of_caller);
+  g_assert (polkit_unix_process_get_uid (POLKIT_UNIX_PROCESS (subject)) >= 0);
+  g_assert (polkit_unix_process_get_start_time (POLKIT_UNIX_PROCESS (subject)) > 0);
 
   error = NULL;
   authority = polkit_authority_get_sync (NULL /* GCancellable* */, &error);
--
cgit v0.8.3-6-g21f6