With Apache 1.3.x, status code 408 is logged to access log when an HTTP request isn't sent within a timeout period. But this function is lost in Apache 2.x. This function is useful for detecting connection flood attack and identifying the attacker's IP address. The following patch for Apache 2.2.2 enables it (also applicable to 2.0.58). --- server/protocol.c.orig Wed Jun 7 15:41:12 2006 +++ server/protocol.c Wed Jun 7 20:45:40 2006 @@ -899,6 +899,13 @@ return r; } + if (r->status == HTTP_REQUEST_TIME_OUT) { + ap_update_child_status(conn->sbh, SERVER_BUSY_LOG, r); + ap_run_log_transaction(r); + apr_brigade_destroy(tmp_bb); + return r; + } + apr_brigade_destroy(tmp_bb); return NULL; }
Fix committed to trunk as r820760 The fix includes the original patch (slightly modified for current trunk code), and a contribution from Stefan Fritsch to make sure a timeout reading the request gets treated as a 408 and not a 400.
Created attachment 25086 [details] Prevent excessive 408 log entries when KeepAlive is on When KeepAlive is on, the original patch results in a log entry for every connection, reporting when the keepalive times out. This results in a large number of 408 status codes in the logs, one for each legitimate connection. The attached patch (also included below) prevents keepalive-related 408 status codes from being logged while still logging 408 status codes for non-keepalive connections, header timeouts (regardless of whether keepalive is enabled), and so on. diff -up httpd-2.3.5-alpha/server/protocol.c.keepalivequiet httpd-2.3.5-alpha/server/protocol.c --- httpd-2.3.5-alpha/server/protocol.c.keepalivequiet 2010-03-04 19:50:04.321471001 -0500 +++ httpd-2.3.5-alpha/server/protocol.c 2010-03-04 21:33:52.657724234 -0500 @@ -923,7 +923,12 @@ request_rec *ap_read_request(conn_rec *c } else if (r->status == HTTP_REQUEST_TIME_OUT) { ap_update_child_status(conn->sbh, SERVER_BUSY_LOG, r); - ap_run_log_transaction(r); + csd = ap_get_module_config(conn->conn_config, &core_module); + apr_socket_timeout_get(csd, &cur_timeout); + if (conn->keepalive != AP_CONN_KEEPALIVE + || cur_timeout != conn->base_server->keep_alive_timeout) { + ap_run_log_transaction(r); + } apr_brigade_destroy(tmp_bb); goto traceout; }
(In reply to comment #2) > Created an attachment (id=25086) [details] > Prevent excessive 408 log entries when KeepAlive is on Thanks for the observation. Fixed slightly different in r919323.
>> Created an attachment (id=25086) [details] >> Prevent excessive 408 log entries when KeepAlive is on > Thanks for the observation. Fixed slightly different in r919323. r919323 is still leaving a lot of 408 errors in Apache logs when Apache is running behind an Amazon Elastic Load Balancer: see https://forums.aws.amazon.com/thread.jspa?messageID=292085񇓵 Patch of r919323 for reference: --- httpd/httpd/trunk/server/protocol.c 2010/03/05 07:30:17 919322 +++ httpd/httpd/trunk/server/protocol.c 2010/03/05 07:37:15 919323 @@ -923,7 +923,9 @@ } else if (r->status == HTTP_REQUEST_TIME_OUT) { ap_update_child_status(conn->sbh, SERVER_BUSY_LOG, r); - ap_run_log_transaction(r); + if (!r->connection->keepalives) { + ap_run_log_transaction(r); + } apr_brigade_destroy(tmp_bb); goto traceout; } I believe !r->connection->keepalives is failing to filter out load balancer connections.
This is definitely still an issue behind Amazon ELB's... I'm getting lots of 408 status codes in my logs.
What exactly?
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