diff options
| -rw-r--r-- | bus/apparmor.c | 339 | ||||
| -rw-r--r-- | bus/apparmor.h | 12 | ||||
| -rw-r--r-- | bus/bus.c | 19 |
3 files changed, 369 insertions, 1 deletions
diff --git a/bus/apparmor.c b/bus/apparmor.c index 3a2426a5..615a5251 100644 --- a/bus/apparmor.c +++ b/bus/apparmor.c @@ -339,6 +339,24 @@ build_service_query (DBusString *query, query_append (query, name); } +static dbus_bool_t +build_message_query (DBusString *query, + const char *src_con, + const char *bustype, + const char *name, + const char *dst_con, + const char *path, + const char *interface, + const char *member) +{ + return build_common_query (query, src_con, bustype) && + query_append (query, name) && + query_append (query, dst_con) && + query_append (query, path) && + query_append (query, interface) && + query_append (query, member); +} + static void set_error_from_query_errno (DBusError *error, int error_number) { @@ -346,6 +364,42 @@ set_error_from_query_errno (DBusError *error, int error_number) "Failed to query AppArmor policy: %s", _dbus_strerror (error_number)); } + +static void +set_error_from_denied_message (DBusError *error, + DBusConnection *sender, + DBusConnection *proposed_recipient, + dbus_bool_t requested_reply, + const char *msgtype, + const char *path, + const char *interface, + const char *member, + const char *error_name, + const char *destination) +{ + const char *proposed_recipient_loginfo; + const char *unset = "(unset)"; + + proposed_recipient_loginfo = proposed_recipient ? + bus_connection_get_loginfo (proposed_recipient) : + "bus"; + + dbus_set_error (error, DBUS_ERROR_ACCESS_DENIED, + "An AppArmor policy prevents this sender from sending this " + "message to this recipient; type=\"%s\", " + "sender=\"%s\" (%s) interface=\"%s\" member=\"%s\" " + "error name=\"%s\" requested_reply=\"%d\" " + "destination=\"%s\" (%s)", + msgtype, + bus_connection_get_name (sender), + bus_connection_get_loginfo (sender), + interface ? interface : unset, + member ? member : unset, + error_name ? error_name : unset, + requested_reply, + destination, + proposed_recipient_loginfo); +} #endif /* HAVE_APPARMOR */ /** @@ -668,3 +722,288 @@ bus_apparmor_allows_acquire_service (DBusConnection *connection, return TRUE; #endif /* HAVE_APPARMOR */ } + +/** + * Check if Apparmor security controls allow the message to be sent to a + * particular connection based on the security context of the sender and + * that of the receiver. The destination connection need not be the + * addressed recipient, it could be an "eavesdropper" + * + * @param sender the sender of the message. + * @param proposed_recipient the connection the message is to be sent to. + * @param requested_reply TRUE if the message is a reply requested by + * proposed_recipient + * @param bustype name of the bus + * @param msgtype message type (DBUS_MESSAGE_TYPE_METHOD_CALL, etc.) + * @param path object path the message should be sent to + * @param interface the type of the object instance + * @param member the member of the object + * @param error_name the name of the error if the message type is error + * @param destination name that the message should be sent to + * @param source name that the message should be sent from + * @param error the reason for failure when FALSE is returned + * @returns TRUE if the message is permitted + */ +dbus_bool_t +bus_apparmor_allows_send (DBusConnection *sender, + DBusConnection *proposed_recipient, + dbus_bool_t requested_reply, + const char *bustype, + int msgtype, + const char *path, + const char *interface, + const char *member, + const char *error_name, + const char *destination, + const char *source, + DBusError *error) +{ +#ifdef HAVE_APPARMOR + BusAppArmorConfinement *src_con = NULL, *dst_con = NULL; + DBusString qstr, auxdata; + dbus_bool_t src_allow = FALSE, dst_allow = FALSE; + dbus_bool_t src_audit = TRUE, dst_audit = TRUE; + dbus_bool_t free_auxdata = FALSE; + unsigned long pid; + int len, res, src_errno = 0, dst_errno = 0; + uint32_t src_perm = AA_DBUS_SEND, dst_perm = AA_DBUS_RECEIVE; + const char *msgtypestr = dbus_message_type_to_string(msgtype); + + if (!apparmor_enabled) + return TRUE; + + _dbus_assert (sender != NULL); + + src_con = bus_connection_dup_apparmor_confinement (sender); + + if (proposed_recipient) + { + dst_con = bus_connection_dup_apparmor_confinement (proposed_recipient); + } + else + { + dst_con = bus_con; + bus_apparmor_confinement_ref (dst_con); + } + + /* map reply messages to initial send and receive permission. That is + * permission to receive a message from X grants permission to reply to X. + * And permission to send a message to Y grants permission to receive a reply + * from Y. Note that this only applies to requested replies. Unrequested + * replies still require a policy query. + */ + if (requested_reply) + { + /* ignore requested reply messages and let dbus reply mapping handle them + * as the send was already allowed + */ + src_allow = TRUE; + dst_allow = TRUE; + goto out; + } + + if (is_unconfined (src_con->context, src_con->mode)) + { + src_allow = TRUE; + src_audit = FALSE; + } + else + { + if (!_dbus_string_init (&qstr)) + goto oom; + + if (!build_message_query (&qstr, src_con->context, bustype, destination, + dst_con->context, path, interface, member)) + { + _dbus_string_free (&qstr); + goto oom; + } + + res = aa_query_label (src_perm, + _dbus_string_get_data (&qstr), + _dbus_string_get_length (&qstr), + &src_allow, &src_audit); + _dbus_string_free (&qstr); + if (res == -1) + { + src_errno = errno; + set_error_from_query_errno (error, src_errno); + goto audit; + } + } + + if (is_unconfined (dst_con->context, dst_con->mode)) + { + dst_allow = TRUE; + dst_audit = FALSE; + } + else + { + if (!_dbus_string_init (&qstr)) + goto oom; + + if (!build_message_query (&qstr, dst_con->context, bustype, source, + src_con->context, path, interface, member)) + { + _dbus_string_free (&qstr); + goto oom; + } + + res = aa_query_label (dst_perm, + _dbus_string_get_data (&qstr), + _dbus_string_get_length (&qstr), + &dst_allow, &dst_audit); + _dbus_string_free (&qstr); + if (res == -1) + { + dst_errno = errno; + set_error_from_query_errno (error, dst_errno); + goto audit; + } + } + + /* Don't fail operations on profiles in complain mode */ + if (modestr_is_complain (src_con->mode)) + src_allow = TRUE; + if (modestr_is_complain (dst_con->mode)) + dst_allow = TRUE; + + if (!src_allow || !dst_allow) + set_error_from_denied_message (error, + sender, + proposed_recipient, + requested_reply, + msgtypestr, + path, + interface, + member, + error_name, + destination); + + /* Don't audit the message if one of the following conditions is true: + * 1) The AppArmor query indicates that auditing should not happen. + * 2) The message is a reply type. Reply message are not audited because + * the AppArmor policy language does not have the notion of a reply + * message. Unrequested replies will be silently discarded if the sender + * does not have permission to send to the receiver or if the receiver + * does not have permission to receive from the sender. + */ + if ((!src_audit && !dst_audit) || + (msgtype == DBUS_MESSAGE_TYPE_METHOD_RETURN || + msgtype == DBUS_MESSAGE_TYPE_ERROR)) + goto out; + + audit: + if (!_dbus_string_init (&auxdata)) + goto oom; + free_auxdata = TRUE; + + if (!_dbus_append_pair_str (&auxdata, "bus", bustype ? bustype : "unknown")) + goto oom; + + if (path && !_dbus_append_pair_str (&auxdata, "path", path)) + goto oom; + + if (interface && !_dbus_append_pair_str (&auxdata, "interface", interface)) + goto oom; + + if (member && !_dbus_append_pair_str (&auxdata, "member", member)) + goto oom; + + if (error_name && !_dbus_append_pair_str (&auxdata, "error_name", error_name)) + goto oom; + + len = _dbus_string_get_length (&auxdata); + + if (src_audit) + { + if (!_dbus_append_mask (&auxdata, src_perm)) + goto oom; + + if (destination && !_dbus_append_pair_str (&auxdata, "name", destination)) + goto oom; + + if (sender && dbus_connection_get_unix_process_id (sender, &pid) && + !_dbus_append_pair_uint (&auxdata, "pid", pid)) + goto oom; + + if (src_con->context && + !_dbus_append_pair_str (&auxdata, "profile", src_con->context)) + goto oom; + + if (proposed_recipient && + dbus_connection_get_unix_process_id (proposed_recipient, &pid) && + !_dbus_append_pair_uint (&auxdata, "peer_pid", pid)) + goto oom; + + if (dst_con->context && + !_dbus_append_pair_str (&auxdata, "peer_profile", dst_con->context)) + goto oom; + + if (src_errno && !_dbus_append_pair_str (&auxdata, "info", strerror (src_errno))) + goto oom; + + if (dst_errno && + !_dbus_append_pair_str (&auxdata, "peer_info", strerror (dst_errno))) + goto oom; + + log_message (src_allow, msgtypestr, &auxdata); + } + if (dst_audit) + { + _dbus_string_set_length (&auxdata, len); + + if (source && !_dbus_append_pair_str (&auxdata, "name", source)) + goto oom; + + if (!_dbus_append_mask (&auxdata, dst_perm)) + goto oom; + + if (proposed_recipient && + dbus_connection_get_unix_process_id (proposed_recipient, &pid) && + !_dbus_append_pair_uint (&auxdata, "pid", pid)) + goto oom; + + if (dst_con->context && + !_dbus_append_pair_str (&auxdata, "profile", dst_con->context)) + goto oom; + + if (sender && dbus_connection_get_unix_process_id (sender, &pid) && + !_dbus_append_pair_uint (&auxdata, "peer_pid", pid)) + goto oom; + + if (src_con->context && + !_dbus_append_pair_str (&auxdata, "peer_profile", src_con->context)) + goto oom; + + if (dst_errno && !_dbus_append_pair_str (&auxdata, "info", strerror (dst_errno))) + goto oom; + + if (src_errno && + !_dbus_append_pair_str (&auxdata, "peer_info", strerror (src_errno))) + goto oom; + + log_message (dst_allow, msgtypestr, &auxdata); + } + + out: + if (src_con != NULL) + bus_apparmor_confinement_unref (src_con); + if (dst_con != NULL) + bus_apparmor_confinement_unref (dst_con); + if (free_auxdata) + _dbus_string_free (&auxdata); + + return src_allow && dst_allow; + + oom: + if (error != NULL && !dbus_error_is_set (error)) + BUS_SET_OOM (error); + src_allow = FALSE; + dst_allow = FALSE; + goto out; + +#else + return TRUE; +#endif /* HAVE_APPARMOR */ +} diff --git a/bus/apparmor.h b/bus/apparmor.h index 4f57c8b3..3f3d6469 100644 --- a/bus/apparmor.h +++ b/bus/apparmor.h @@ -46,5 +46,17 @@ dbus_bool_t bus_apparmor_allows_acquire_service (DBusConnection *connection, const char *bustype, const char *service_name, DBusError *error); +dbus_bool_t bus_apparmor_allows_send (DBusConnection *sender, + DBusConnection *proposed_recipient, + dbus_bool_t requested_reply, + const char *bustype, + int msgtype, + const char *path, + const char *interface, + const char *member, + const char *error_name, + const char *destination, + const char *source, + DBusError *error); #endif /* BUS_APPARMOR_H */ @@ -1521,7 +1521,7 @@ bus_context_check_security_policy (BusContext *context, DBusMessage *message, DBusError *error) { - const char *dest; + const char *src, *dest; BusClientPolicy *sender_policy; BusClientPolicy *recipient_policy; dbus_int32_t toggles; @@ -1530,6 +1530,7 @@ bus_context_check_security_policy (BusContext *context, dbus_bool_t requested_reply; type = dbus_message_get_type (message); + src = dbus_message_get_sender (message); dest = dbus_message_get_destination (message); /* dispatch.c was supposed to ensure these invariants */ @@ -1619,6 +1620,22 @@ bus_context_check_security_policy (BusContext *context, return FALSE; } + /* next verify AppArmor access controls. If allowed then + * go on with the standard checks. + */ + if (!bus_apparmor_allows_send (sender, proposed_recipient, + requested_reply, + bus_context_get_type (context), + dbus_message_get_type (message), + dbus_message_get_path (message), + dbus_message_get_interface (message), + dbus_message_get_member (message), + dbus_message_get_error_name (message), + dest ? dest : DBUS_SERVICE_DBUS, + src ? src : DBUS_SERVICE_DBUS, + error)) + return FALSE; + if (!bus_connection_is_active (sender)) { /* Policy for inactive connections is that they can only send |