Attachment 125883 Details for Bug 96577 – On bus startup check given auth in config file against supported mechanismen.

[patch] On bus startup check given auth in config file against supported mechanismen.

On-bus-startup-check-given-auth-in-config-file-aga.patch (text/plain), 3.74 KB, created by Ralf Habacker on 2016-08-18 17:15:13 UTC

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Creator: Ralf Habacker

Created: 2016-08-18 17:15:13 UTC

Size: 3.74 KB

patch

obsolete

>From a12dbdf48c227ed67557347e4e59ad74a7a1c597 Mon Sep 17 00:00:00 2001
>From: Ralf Habacker <ralf.habacker@freenet.de>
>Date: Thu, 18 Aug 2016 19:14:19 +0200
>Subject: [PATCH] On bus startup check given auth in config file against
> supported mechanismen.
>
>This fixes a security hole caused by dbus-daemon ignoring misspelled or
>unsupported auth mechanismen in bus config file and falling back silently
>to a less secure authentification level.
>
>Bug: https://bugs.freedesktop.org/show_bug.cgi?id=96577
>---
> bus/bus.c        | 16 ++++++++++++++++
> dbus/dbus-auth.c | 41 +++++++++++++++++++++++++++++++++++++++++
> dbus/dbus-auth.h |  4 ++++
> 3 files changed, 61 insertions(+)
>
>diff --git a/bus/bus.c b/bus/bus.c
>index 103447c..92f3af1 100644
>--- a/bus/bus.c
>+++ b/bus/bus.c
>@@ -37,6 +37,7 @@
> #include "apparmor.h"
> #include "audit.h"
> #include "dir-watch.h"
>+#include <dbus/dbus-auth.h>
> #include <dbus/dbus-list.h>
> #include <dbus/dbus-hash.h>
> #include <dbus/dbus-credentials.h>
>@@ -408,6 +409,21 @@ process_config_first_time_only (BusContext       *context,
>       link = _dbus_list_get_first_link (auth_mechanisms_list);
>       while (link != NULL)
>         {
>+          DBusString name;
>+          _dbus_string_init_const (&name, link->data);
>+          if (!_dbus_auth_is_supported_mechanismus (&name))
>+            {
>+              DBusString list;
>+              _dbus_string_init (&list);
>+              _dbus_auth_get_supported_mechanismen (&list);
>+              dbus_set_error (error, DBUS_ERROR_FAILED,
>+                              "Unsupported auth mechanismus \"%s\" in bus config file detected. Supported mechanismen are \"%s\".",
>+                              link->data,
>+                              _dbus_string_get_const_data (&list));
>+              _dbus_string_free (&list);
>+              retval = FALSE;
>+              goto failed;
>+            }
>           auth_mechanisms[i] = _dbus_strdup (link->data);
>           if (auth_mechanisms[i] == NULL)
>             goto oom;
>diff --git a/dbus/dbus-auth.c b/dbus/dbus-auth.c
>index 18c12b4..206ab32 100644
>--- a/dbus/dbus-auth.c
>+++ b/dbus/dbus-auth.c
>@@ -3002,6 +3002,47 @@ _dbus_auth_get_unix_fd_negotiated(DBusAuth *auth)
>   return auth->unix_fd_negotiated;
> }
> 
>+/**
>+ * Queries whether the given auth mechanismus is supported.
>+ *
>+ * @param auth the auth mechanismus to query for
>+ * @returns #TRUE when auth mechanismus is supported
>+ */
>+dbus_bool_t
>+_dbus_auth_is_supported_mechanismus(DBusString *name)
>+{
>+  _dbus_assert (name != NULL);
>+
>+  return find_mech(name, NULL) != 0;
>+}
>+
>+/**
>+ * Return string containing all supported auth mechanismen.
>+ *
>+ * @param string to hold the supported auth mechanismen
>+ * @returns #FALSE on oom
>+ */
>+dbus_bool_t
>+_dbus_auth_get_supported_mechanismen(DBusString *buffer)
>+{
>+  int i;
>+  _dbus_assert (buffer != NULL);
>+
>+  i = 0;
>+  while (all_mechanisms[i].mechanism != NULL)
>+    {
>+      if (i > 0)
>+        {
>+          if (!_dbus_string_append (buffer, " "))
>+            return FALSE;
>+        }
>+      if (!_dbus_string_append (buffer, all_mechanisms[i].mechanism))
>+        return FALSE;
>+      ++i;
>+    }
>+  return TRUE;
>+}
>+
> /** @} */
> 
> /* tests in dbus-auth-util.c */
>diff --git a/dbus/dbus-auth.h b/dbus/dbus-auth.h
>index c62bcd1..e475f75 100644
>--- a/dbus/dbus-auth.h
>+++ b/dbus/dbus-auth.h
>@@ -92,6 +92,10 @@ const char*   _dbus_auth_get_guid_from_server(DBusAuth               *auth);
> 
> void          _dbus_auth_set_unix_fd_possible(DBusAuth               *auth, dbus_bool_t b);
> dbus_bool_t   _dbus_auth_get_unix_fd_negotiated(DBusAuth             *auth);
>+DBUS_PRIVATE_EXPORT
>+dbus_bool_t   _dbus_auth_is_supported_mechanismus(DBusString         *name);
>+DBUS_PRIVATE_EXPORT
>+dbus_bool_t   _dbus_auth_get_supported_mechanismen(DBusString        *buffer);
> 
> DBUS_END_DECLS
> 
>-- 
>2.6.6

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