Fix CVE-2018-19788: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-19788 https://gitlab.freedesktop.org/polkit/polkit/issues/74 Patch copied from upstream source repository: https://gitlab.freedesktop.org/polkit/polkit/commit/2cb40c4d5feeaa09325522bd7d97910f1b59e379 From 2cb40c4d5feeaa09325522bd7d97910f1b59e379 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= Date: Mon, 3 Dec 2018 10:28:58 +0100 Subject: [PATCH] Allow negative uids/gids in PolkitUnixUser and Group objects (uid_t) -1 is still used as placeholder to mean "unset". This is OK, since there should be no users with such number, see https://systemd.io/UIDS-GIDS#special-linux-uids. (uid_t) -1 is used as the default value in class initialization. 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 accept such gids, except for -1. A nicer fix would be to change the underlying type to e.g. uint32 to not have negative values. 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 unsigned, 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. --- src/polkit/polkitunixgroup.c | 15 +++++++++++---- src/polkit/polkitunixprocess.c | 12 ++++++++---- src/polkit/polkitunixuser.c | 13 ++++++++++--- 3 files changed, 29 insertions(+), 11 deletions(-) diff --git a/src/polkit/polkitunixgroup.c b/src/polkit/polkitunixgroup.c index c57a1aa..309f689 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 (PGNU Guix consists of Scheme code that implements the deployment model of the Nix package management tool. In fact, it currently talks to a build daemon whose code comes from Nix (see the manual for details.) Nix was initially written by Eelco Dolstra; other people have been contributing to it. See `nix/AUTHORS' for details. The list of GNU Guix contributors is now generated from the output of 'git log' and written to this file, as can be seen in release tarballs.
generated by cgit
NIX group ID", - 0, + G_MININT, G_MAXINT, - 0, + -1, G_PARAM_CONSTRUCT | G_PARAM_READWRITE | G_PARAM_STATIC_NAME | @@ -166,9 +170,10 @@ polkit_unix_group_get_gid (PolkitUnixGroup *group) */ void polkit_unix_group_set_gid (PolkitUnixGroup *group, - gint gid) + gint gid) { g_return_if_fail (POLKIT_IS_UNIX_GROUP (group)); + g_return_if_fail (gid != -1); 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 != -1, NULL); + return POLKIT_IDENTITY (g_object_new (POLKIT_TYPE_UNIX_GROUP, "gid", gid, NULL)); diff --git a/src/polkit/polkitunixprocess.c b/src/polkit/polkitunixprocess.c index 972b777..b02b258 100644 --- a/src/polkit/polkitunixprocess.c +++ b/src/polkit/polkitunixprocess.c @@ -159,9 +159,14 @@ 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)); + case PROP_UID: { + gint val; + + val = g_value_get_int (value); + g_return_if_fail (val != -1); + polkit_unix_process_set_uid (unix_process, val); break; + } case PROP_START_TIME: polkit_unix_process_set_start_time (unix_process, g_value_get_uint64 (value)); @@ -239,7 +244,7 @@ polkit_unix_process_class_init (PolkitUnixProcessClass *klass) g_param_spec_int ("uid", "User ID", "The UNIX user ID", - -1, + G_MININT, G_MAXINT, -1, G_PARAM_CONSTRUCT | @@ -303,7 +308,6 @@ 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; } diff --git a/src/polkit/polkitunixuser.c b/src/polkit/polkitunixuser.c index 8bfd3a1..234a697 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; /* (uid_t) -1 is not a valid UID under Linux */ unix_user->name = NULL; } @@ -112,11 +113,14 @@ polkit_unix_user_set_property (GObject *object, GParamSpec *pspec) { PolkitUnixUser *unix_user = POLKIT_UNIX_USER (object); + gint val; switch (prop_id) { case PROP_UID: - unix_user->uid = g_value_get_int (value); + val = g_value_get_int (value); + g_return_if_fail (val != -1); + unix_user->uid = val; break; default: @@ -144,9 +148,9 @@ polkit_unix_user_class_init (PolkitUnixUserClass *klass) g_param_spec_int ("uid", "User ID", "The UNIX user ID", - 0, + G_MININT, G_MAXINT, - 0, + -1, G_PARAM_CONSTRUCT | G_PARAM_READWRITE | G_PARAM_STATIC_NAME | @@ -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 != -1); 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 != -1, NULL); + return POLKIT_IDENTITY (g_object_new (POLKIT_TYPE_UNIX_USER, "uid", uid, NULL)); -- 2.18.1