Attachment 136687 Details for Bug 104588 – _dbus_credentials_add_from_user: Only accept numeric uid for EXTERNAL

[patch] _dbus_credentials_add_from_user: Only accept numeric uid for EXTERNAL

0004-_dbus_credentials_add_from_user-Only-accept-numeric-.patch (text/plain), 4.65 KB, created by Simon McVittie on 2018-01-12 16:57:21 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Simon McVittie

Created: 2018-01-12 16:57:21 UTC

Size: 4.65 KB

patch

obsolete

>From dad9c269fae442893400df3287e4194b633f75e0 Mon Sep 17 00:00:00 2001
>From: Simon McVittie <smcv@collabora.com>
>Date: Fri, 12 Jan 2018 16:09:08 +0000
>Subject: [PATCH 4/7] _dbus_credentials_add_from_user: Only accept numeric uid
> for EXTERNAL
>
>In the well-known system dbus-daemon, it's desirable to avoid looking
>up non-numeric authorization identities in the user database, because
>that could deadlock with NSS modules that directly or indirectly
>require the system bus. Add a flag for whether the username will be
>looked up in the userdb, and don't set that flag for EXTERNAL auth
>(which is what we use on the system bus, and on the session bus
>if not configured otherwise).
>
>DBUS_COOKIE_SHA1 authentication is documented in terms of the
>username (although in fact libdbus sends a numeric uid there too,
>and GDBus only accepts a numeric uid) so continue to use the userdb
>for that mechanism. DBUS_COOKIE_SHA1 needs to use the userdb on Unix
>anyway, otherwise it won't find the user's home directory.
>
>Signed-off-by: Simon McVittie <smcv@collabora.com>
>Bug: https://bugs.freedesktop.org/show_bug.cgi?id=104588
>---
> dbus/dbus-auth.c        | 2 ++
> dbus/dbus-sysdeps-win.c | 1 +
> dbus/dbus-sysdeps.h     | 7 +++++++
> dbus/dbus-userdb.c      | 9 +++++++++
> 4 files changed, 19 insertions(+)
>
>diff --git a/dbus/dbus-auth.c b/dbus/dbus-auth.c
>index 06de633a..3182026c 100644
>--- a/dbus/dbus-auth.c
>+++ b/dbus/dbus-auth.c
>@@ -550,6 +550,7 @@ sha1_handle_first_client_response (DBusAuth         *auth,
>     }
>       
>   if (!_dbus_credentials_add_from_user (auth->desired_identity, data,
>+                                        DBUS_CREDENTIALS_ADD_FLAGS_USER_DATABASE,
>                                         &error))
>     {
>       if (dbus_error_has_name (&error, DBUS_ERROR_NO_MEMORY))
>@@ -1120,6 +1121,7 @@ handle_server_data_external_mech (DBusAuth         *auth,
> 
>       if (!_dbus_credentials_add_from_user (auth->desired_identity,
>                                             &auth->identity,
>+                                            DBUS_CREDENTIALS_ADD_FLAGS_NONE,
>                                             &error))
>         {
>           if (dbus_error_has_name (&error, DBUS_ERROR_NO_MEMORY))
>diff --git a/dbus/dbus-sysdeps-win.c b/dbus/dbus-sysdeps-win.c
>index 4ad87edc..4e71d1cf 100644
>--- a/dbus/dbus-sysdeps-win.c
>+++ b/dbus/dbus-sysdeps-win.c
>@@ -2066,6 +2066,7 @@ _dbus_concat_dir_and_file (DBusString       *dir,
> dbus_bool_t
> _dbus_credentials_add_from_user (DBusCredentials         *credentials,
>                                  const DBusString        *username,
>+                                 DBusCredentialsAddFlags  flags,
>                                  DBusError               *error)
> {
>   if (!_dbus_credentials_add_windows_sid (credentials,
>diff --git a/dbus/dbus-sysdeps.h b/dbus/dbus-sysdeps.h
>index 48d3e766..b9b0c440 100644
>--- a/dbus/dbus-sysdeps.h
>+++ b/dbus/dbus-sysdeps.h
>@@ -240,8 +240,15 @@ dbus_bool_t _dbus_read_credentials_socket (DBusSocket        client_fd,
> dbus_bool_t _dbus_send_credentials_socket (DBusSocket       server_fd,
>                                            DBusError       *error);
> 
>+typedef enum
>+{
>+  DBUS_CREDENTIALS_ADD_FLAGS_USER_DATABASE = (1 << 0),
>+  DBUS_CREDENTIALS_ADD_FLAGS_NONE = 0
>+} DBusCredentialsAddFlags;
>+
> dbus_bool_t _dbus_credentials_add_from_user            (DBusCredentials         *credentials,
>                                                         const DBusString        *username,
>+                                                        DBusCredentialsAddFlags  flags,
>                                                         DBusError               *error);
> 
> dbus_bool_t _dbus_credentials_add_from_current_process (DBusCredentials  *credentials);
>diff --git a/dbus/dbus-userdb.c b/dbus/dbus-userdb.c
>index b96aef43..e765e794 100644
>--- a/dbus/dbus-userdb.c
>+++ b/dbus/dbus-userdb.c
>@@ -526,6 +526,7 @@ _dbus_homedir_from_uid (dbus_uid_t         uid,
> dbus_bool_t
> _dbus_credentials_add_from_user (DBusCredentials         *credentials,
>                                  const DBusString        *username,
>+                                 DBusCredentialsAddFlags  flags,
>                                  DBusError               *error)
> {
>   DBusUserDatabase *db;
>@@ -543,6 +544,14 @@ _dbus_credentials_add_from_user (DBusCredentials         *credentials,
>       return TRUE;
>     }
> 
>+  /* If we aren't allowed to look in NSS or /etc/passwd, fail now. */
>+  if (!(flags & DBUS_CREDENTIALS_ADD_FLAGS_USER_DATABASE))
>+    {
>+      dbus_set_error (error, DBUS_ERROR_INVALID_ARGS,
>+                      "Expected a numeric Unix uid");
>+      return FALSE;
>+    }
>+
>   if (!_dbus_user_database_lock_system ())
>     {
>       _DBUS_SET_OOM (error);
>-- 
>2.15.1
>

Actions: View | Splinter Review

Attachments on bug 104588: 136684 | 136685 | 136686 | 136687 | 136688 | 136689 | 136690 | 136728 | 136729 | 136755

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.