Commit bbf11cd5 authored by Alban Crequy's avatar Alban Crequy Committed by Simon McVittie

config: add new limit: pending_fd_timeout

This is one of four commits needed to address CVE-2014-3637.

When a file descriptor is passed to dbus-daemon, the associated D-Bus message
might not be fully sent to dbus-daemon yet. Dbus-daemon keeps the file
descriptor in the DBusMessageLoader of the connection, waiting for the rest of
the message. If the client stops sending the remaining bytes, dbus-daemon will
wait forever and keep that file descriptor.

This patch adds pending_fd_timeout (milliseconds) in the configuration to
disconnect a connection after a timeout when a file descriptor was sent but not
the remaining message.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=80559Reviewed-by: 's avatarSimon McVittie <simon.mcvittie@collabora.co.uk>
parent 8ad179a8
......@@ -1240,6 +1240,12 @@ bus_context_get_auth_timeout (BusContext *context)
return context->limits.auth_timeout;
}
int
bus_context_get_pending_fd_timeout (BusContext *context)
{
return context->limits.pending_fd_timeout;
}
int
bus_context_get_max_completed_connections (BusContext *context)
{
......
......@@ -54,6 +54,7 @@ typedef struct
long max_message_unix_fds; /**< Max number of unix fds of a single message*/
int activation_timeout; /**< How long to wait for an activation to time out */
int auth_timeout; /**< How long to wait for an authentication to time out */
int pending_fd_timeout; /**< How long to wait for a D-Bus message with a fd to time out */
int max_completed_connections; /**< Max number of authorized connections */
int max_incomplete_connections; /**< Max number of incomplete connections */
int max_connections_per_user; /**< Max number of connections auth'd as same user */
......@@ -106,6 +107,7 @@ BusClientPolicy* bus_context_create_client_policy (BusContext
DBusError *error);
int bus_context_get_activation_timeout (BusContext *context);
int bus_context_get_auth_timeout (BusContext *context);
int bus_context_get_pending_fd_timeout (BusContext *context);
int bus_context_get_max_completed_connections (BusContext *context);
int bus_context_get_max_incomplete_connections (BusContext *context);
int bus_context_get_max_connections_per_user (BusContext *context);
......
......@@ -439,6 +439,11 @@ bus_config_parser_new (const DBusString *basedir,
* password) is allowed, then potentially it has to be quite long.
*/
parser->limits.auth_timeout = 5000; /* 5 seconds */
/* Do not allow a fd to stay forever in dbus-daemon
* https://bugs.freedesktop.org/show_bug.cgi?id=80559
*/
parser->limits.pending_fd_timeout = 150000; /* 2.5 minutes */
parser->limits.max_incomplete_connections = 64;
parser->limits.max_connections_per_user = 256;
......@@ -1902,6 +1907,12 @@ set_limit (BusConfigParser *parser,
must_be_int = TRUE;
parser->limits.auth_timeout = value;
}
else if (strcmp (name, "pending_fd_timeout") == 0)
{
must_be_positive = TRUE;
must_be_int = TRUE;
parser->limits.pending_fd_timeout = value;
}
else if (strcmp (name, "reply_timeout") == 0)
{
must_be_positive = TRUE;
......@@ -3108,6 +3119,7 @@ limits_equal (const BusLimits *a,
|| a->max_message_unix_fds == b->max_message_unix_fds
|| a->activation_timeout == b->activation_timeout
|| a->auth_timeout == b->auth_timeout
|| a->pending_fd_timeout == b->pending_fd_timeout
|| a->max_completed_connections == b->max_completed_connections
|| a->max_incomplete_connections == b->max_incomplete_connections
|| a->max_connections_per_user == b->max_connections_per_user
......
......@@ -53,6 +53,7 @@
limit is also relatively low -->
<limit name="service_start_timeout">120000</limit>
<limit name="auth_timeout">240000</limit>
<limit name="pending_fd_timeout">150000</limit>
<limit name="max_completed_connections">100000</limit>
<limit name="max_incomplete_connections">10000</limit>
<limit name="max_connections_per_user">100000</limit>
......
......@@ -528,6 +528,10 @@ Available limit names are:</para>
"auth_timeout" : milliseconds (thousandths) a
connection is given to
authenticate
"pending_fd_timeout" : milliseconds (thousandths) a
fd is given to be transmitted to
dbus-daemon before disconnecting the
connection
"max_completed_connections" : max number of authenticated connections
"max_incomplete_connections" : max number of unauthenticated
connections
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment