Fix tls_ctx_client/server_new leaving error on OpenSSL error stack

In the corner case that the global OpenSSL has an invalid command like

	MinProtocol = TLSv1.0

(due to OpenSSL's idiosyncrasies MinProtocol = TLSv1 would be correct)
the SSL_ctx_new function leaves the errors for parsing the config file
on the stack.

  OpenSSL: error:14187180:SSL routines:ssl_do_config:bad value

Since the later functions, especially the one of loading the
certificates expected a clean error this error got reported at the
wrong place.

Print the warnings with crypto_msg when we detect that we are in this
situation (this also clears the stack).

Debian Bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=958296

Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20200421101122.24284-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg19802.html

Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/src/openvpn/ssl_openssl.c b/src/openvpn/ssl_openssl.c
index 5955c6bdfc559cd1b9467a2c3adefe8fb0aeef69..555cbbdfe8eff5e3f993d253d03dc0b43b726e05 100644 (file)
--- a/src/openvpn/ssl_openssl.c
+++ b/src/openvpn/ssl_openssl.c
@@ -115,6 +115,11 @@ tls_ctx_server_new(struct tls_root_ctx *ctx)
     {
         crypto_msg(M_FATAL, "SSL_CTX_new SSLv23_server_method");
     }
+    if (ERR_peek_error() != 0)
+    {
+        crypto_msg(M_WARN, "Warning: TLS server context initialisation "
+                   "has warnings.");
+    }
 }
 
 void
@@ -128,6 +133,11 @@ tls_ctx_client_new(struct tls_root_ctx *ctx)
     {
         crypto_msg(M_FATAL, "SSL_CTX_new SSLv23_client_method");
     }
+    if (ERR_peek_error() != 0)
+    {
+        crypto_msg(M_WARN, "Warning: TLS client context initialisation "
+                   "has warnings.");
+    }
 }
 
 void