user/polkit: CVE-2018-19788

1 files changed, 183 insertions, 0 deletions

diff --git a/user/polkit/CVE-2018-19788.patch b/user/polkit/CVE-2018-19788.patch
new file mode 100644
index 000000000..6a2845aca
--- /dev/null
+++ b/user/polkit/CVE-2018-19788.patch
@@ -0,0 +1,183 @@
+From 35af308b530f36c1a0a912387106a59b3ab92027 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
+Date: Mon, 3 Dec 2018 10:28:58 +0100
+Subject: [PATCH 1/2] Use default of -1 for uid/gid in class initialization
+
+This doesn't seem to change anything in polkitd behaviour, but it
+seems cleaner to default to -1 which here means "unset".
+---
+ src/polkit/polkitunixgroup.c | 4 ++--
+ src/polkit/polkitunixuser.c  | 4 ++--
+ 2 files changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/src/polkit/polkitunixgroup.c b/src/polkit/polkitunixgroup.c
+index c57a1aa..095cca0 100644
+--- a/src/polkit/polkitunixgroup.c
++++ b/src/polkit/polkitunixgroup.c
+@@ -131,9 +131,9 @@ polkit_unix_group_class_init (PolkitUnixGroupClass *klass)
+                                    g_param_spec_int ("gid",
+                                                      "Group ID",
+                                                      "The UNIX group ID",
+-                                                     0,
++                                                     -1,
+                                                      G_MAXINT,
+-                                                     0,
++                                                     -1,
+                                                      G_PARAM_CONSTRUCT |
+                                                      G_PARAM_READWRITE |
+                                                      G_PARAM_STATIC_NAME |
+diff --git a/src/polkit/polkitunixuser.c b/src/polkit/polkitunixuser.c
+index 8bfd3a1..a5285f4 100644
+--- a/src/polkit/polkitunixuser.c
++++ b/src/polkit/polkitunixuser.c
+@@ -144,9 +144,9 @@ polkit_unix_user_class_init (PolkitUnixUserClass *klass)
+                                    g_param_spec_int ("uid",
+                                                      "User ID",
+                                                      "The UNIX user ID",
+-                                                     0,
++                                                     -1,
+                                                      G_MAXINT,
+-                                                     0,
++                                                     -1,
+                                                      G_PARAM_CONSTRUCT |
+                                                      G_PARAM_READWRITE |
+                                                      G_PARAM_STATIC_NAME |
+-- 
+2.18.1
+
+
+From fbaab32cb4ed9ed5f1e3eea6cd317d443aa427dc Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
+Date: Mon, 3 Dec 2018 12:51:26 +0100
+Subject: [PATCH 2/2] Check gid and uid initalization in PolkitUnixUser and
+ Group objects
+
+When a user or group above INT32_MAX is created, the numeric uid or
+gid wraps around to negative when the value is assigned to gint, and
+polkit gets confused. Let's refuse such uids and gids.
+
+This patch just refuses to initialize uid and gid values to negative.
+A nicer fix is to change the underlying type to e.g. gint64 to allow
+the full range of values in uid_t and gid_t to be represented. But
+this cannot be done without breaking the API, so likely new functions
+will have to be added (a polkit_unix_user_new variant that takes a
+gint64, and the same for _group_new, _set_uid, _get_uid, _set_gid,
+_get_gid, etc.). This will require a bigger patch.
+
+Fixes https://gitlab.freedesktop.org/polkit/polkit/issues/74.
+
+Example sessions from uid=4000000000:
+
+Dec 03 14:35:08 krowka polkitd[21432]: system-bus-name::1.41869 is inquiring whether system-bus-name::1.79432 is authorized for org.freedesktop.systemd1.manage-units
+Dec 03 14:35:08 krowka polkitd[21432]:  user of caller is unix-user:root
+Dec 03 14:35:08 krowka polkitd[21432]: polkit_unix_user_new: assertion 'uid >= 0' failed
+Dec 03 14:35:08 krowka polkitd[21432]: polkit_identity_to_string: assertion 'POLKIT_IS_IDENTITY (identity)' failed
+Dec 03 14:35:08 krowka polkitd[21432]:  user of subject is (null)
+Dec 03 14:35:08 krowka polkitd[21432]: polkit_identity_equal: assertion 'POLKIT_IS_IDENTITY (b)' failed
+Dec 03 14:35:08 krowka polkitd[21432]: checking whether system-bus-name::1.79432 is authorized for org.freedesktop.systemd1.manage-units
+Dec 03 14:35:08 krowka polkitd[21432]: polkit_unix_user_new: assertion 'uid >= 0' failed
+Dec 03 14:35:08 krowka polkitd[21432]:
+Dec 03 14:35:08 krowka polkitd[21432]: polkit_authorization_result_get_is_challenge: assertion 'POLKIT_IS_AUTHORIZATION_RESULT (result)' failed
+Dec 03 14:35:08 krowka polkitd[21432]: g_object_ref: assertion 'G_IS_OBJECT (object)' failed
+Dec 03 14:35:08 krowka polkitd[21432]: g_object_ref: assertion 'G_IS_OBJECT (object)' failed
+Dec 03 14:35:08 krowka polkitd[21432]: polkit_authorization_result_get_details: assertion 'POLKIT_IS_AUTHORIZATION_RESULT (result)' failed
+Dec 03 14:35:08 krowka polkitd[21432]: polkit_authorization_result_get_is_challenge: assertion 'POLKIT_IS_AUTHORIZATION_RESULT (result)' failed
+Dec 03 14:35:08 krowka polkitd[21432]: polkit_authorization_result_get_is_authorized: assertion 'POLKIT_IS_AUTHORIZATION_RESULT (result)' failed
+Dec 03 14:35:08 krowka polkitd[21432]: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
+Dec 03 14:35:08 krowka polkitd[21432]: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
+---
+ src/polkit/polkitunixgroup.c | 9 ++++++++-
+ src/polkit/polkitunixuser.c  | 7 +++++++
+ 2 files changed, 15 insertions(+), 1 deletion(-)
+
+diff --git a/src/polkit/polkitunixgroup.c b/src/polkit/polkitunixgroup.c
+index 095cca0..53db862 100644
+--- a/src/polkit/polkitunixgroup.c
++++ b/src/polkit/polkitunixgroup.c
+@@ -71,6 +71,7 @@ G_DEFINE_TYPE_WITH_CODE (PolkitUnixGroup, polkit_unix_group, G_TYPE_OBJECT,
+ static void
+ polkit_unix_group_init (PolkitUnixGroup *unix_group)
+ {
++  unix_group->gid = -1;
+ }
+ 
+ static void
+@@ -100,11 +101,14 @@ polkit_unix_group_set_property (GObject      *object,
+                                GParamSpec   *pspec)
+ {
+   PolkitUnixGroup *unix_group = POLKIT_UNIX_GROUP (object);
++  gint val;
+ 
+   switch (prop_id)
+     {
+     case PROP_GID:
+-      unix_group->gid = g_value_get_int (value);
++      val = g_value_get_int (value);
++      g_return_if_fail (val >= 0);
++      unix_group->gid = val;
+       break;
+ 
+     default:
+@@ -169,6 +173,7 @@ polkit_unix_group_set_gid (PolkitUnixGroup *group,
+                           gint gid)
+ {
+   g_return_if_fail (POLKIT_IS_UNIX_GROUP (group));
++  g_return_if_fail (gid >= 0);
+   group->gid = gid;
+ }
+ 
+@@ -183,6 +188,8 @@ polkit_unix_group_set_gid (PolkitUnixGroup *group,
+ PolkitIdentity *
+ polkit_unix_group_new (gint gid)
+ {
++  g_return_val_if_fail (gid >= 0, NULL);
++
+   return POLKIT_IDENTITY (g_object_new (POLKIT_TYPE_UNIX_GROUP,
+                                        "gid", gid,
+                                        NULL));
+diff --git a/src/polkit/polkitunixuser.c b/src/polkit/polkitunixuser.c
+index a5285f4..ef6403e 100644
+--- a/src/polkit/polkitunixuser.c
++++ b/src/polkit/polkitunixuser.c
+@@ -72,6 +72,7 @@ G_DEFINE_TYPE_WITH_CODE (PolkitUnixUser, polkit_unix_user, G_TYPE_OBJECT,
+ static void
+ polkit_unix_user_init (PolkitUnixUser *unix_user)
+ {
++  unix_user->uid = -1;
+   unix_user->name = NULL;
+ }
+ 
+@@ -112,10 +113,13 @@ polkit_unix_user_set_property (GObject      *object,
+                                GParamSpec   *pspec)
+ {
+   PolkitUnixUser *unix_user = POLKIT_UNIX_USER (object);
++  gint val;
+ 
+   switch (prop_id)
+     {
+     case PROP_UID:
++      val = g_value_get_int (value);
++      g_return_if_fail (val >= 0);
+       unix_user->uid = g_value_get_int (value);
+       break;
+ 
+@@ -182,6 +186,7 @@ polkit_unix_user_set_uid (PolkitUnixUser *user,
+                           gint uid)
+ {
+   g_return_if_fail (POLKIT_IS_UNIX_USER (user));
++  g_return_if_fail (uid >= 0);
+   user->uid = uid;
+ }
+ 
+@@ -196,6 +201,8 @@ polkit_unix_user_set_uid (PolkitUnixUser *user,
+ PolkitIdentity *
+ polkit_unix_user_new (gint uid)
+ {
++  g_return_val_if_fail (uid >= 0, NULL);
++
+   return POLKIT_IDENTITY (g_object_new (POLKIT_TYPE_UNIX_USER,
+                                         "uid", uid,
+                                         NULL));
+-- 
+2.18.1
+