From 77cfeadfa6405c5808273f1d3cc8e89eb17e5f08 Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Fri, 14 May 2010 22:34:10 +0200 Subject: OpenSSL: multi interface handshake could hang John-Mark Bell filed bug #3000052 that identified a problem (with an associated patch) with the OpenSSL handshake state machine when the multi interface is used: Performing an https request using a curl multi handle and using select or epoll to wait for events results in a hang. It appears that the cause is the fix for bug #2958179, which makes ossl_connect_common unconditionally return from the step 2 loop when fetching from a multi handle. When ossl_connect_step2 has completed, it updates connssl->connecting_state to ssl_connect_3. ossl_connect_common will then return to the caller, as a multi handle is in use. Eventually, the client code will call curl_multi_fdset to obtain an updated fdset to select or epoll on. For https requests, curl_multi_fdset will cause https_getsock to be called. https_getsock will only return a socket handle if the connecting_state is ssl_connect_2_reading or ssl_connect_2_writing. Therefore, the client will never obtain a valid fdset, and thus not drive the multi handle, resulting in a hang. (http://curl.haxx.se/bug/view.cgi?id=3000052) --- lib/ssluse.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/ssluse.c b/lib/ssluse.c index ce62605e8..01eba90db 100644 --- a/lib/ssluse.c +++ b/lib/ssluse.c @@ -2425,8 +2425,18 @@ ossl_connect_common(struct connectdata *conn, /* socket is readable or writable */ } + /* Run transaction, and return to the caller if it failed or if + * this connection is part of a multi handle and this loop would + * execute again. This permits the owner of a multi handle to + * abort a connection attempt before step2 has completed while + * ensuring that a client using select() or epoll() will always + * have a valid fdset to wait on. + */ retcode = ossl_connect_step2(conn, sockindex); - if(retcode || (data->state.used_interface == Curl_if_multi)) + if(retcode || (data->state.used_interface == Curl_if_multi && + (ssl_connect_2 == connssl->connecting_state || + ssl_connect_2_reading == connssl->connecting_state || + ssl_connect_2_writing == connssl->connecting_state))) return retcode; } /* repeat step2 until all transactions are done. */ -- cgit v1.2.3