Apache HTTP服务器发生间歇性SSL握手错误

Question

我发现Java客户端和浏览器通过Apache HTTP服务器访问站点时发生间歇性SSL握手错误。这种情况很少发生，但它每天都会破坏构建并影响用户体验。服务器配置为建立安全连接，但不需要来自客户端的证书。

我已经在Java测试客户端和服务器上开启了SSL调试输出（见下文）。我所观察到的是，无论何时发生握手异常，服务器似乎都发送了客户端证书的请求。我不明白为什么它会这样做，为什么这只会偶尔发生。当它发送证书请求时，几乎总是发生错误，但是我也在成功的情况下捕获了请求（可能有1％的时间，99％的失败）。

客户端使用Java 8（1.8.0_31-b13），Apache HTTP服务器版本为2.2.19。

下面是从日志片段：

1）Apache配置摘录

SSLProtocol ALL -SSLv2 -SSLv3 
SSLCertificateFile <path-to-pem1> 
SSLCertificateChainFile <path-to-pem2> 
SSLCACertificateFile <path-to-pem3> 
SSLVerifyDepth 10 
SSLVerifyClient none 

的.PEM文件是可读的。

2）客户端日志（severly略）

*** ClientHello, TLSv1.2 
*** 
*** ServerHello, TLSv1 
*** 
*** Certificate chain 
*** 
*** Diffie-Hellman ServerKeyExchange 
*** CertificateRequest 
*** ServerHelloDone 
*** Certificate chain 
*** 
*** ClientKeyExchange, DH 
*** Finished 
*** 
... 
main, WRITE: TLSv1 Handshake, length = 48 
main, waiting for close_notify or alert: state 1 
main, Exception while waiting for close java.net.SocketException: Software caused connection abort: recv failed 
main, handling exception: java.net.SocketException: Software caused connection abort: recv failed 
%% Invalidated: [Session-1, TLS_DHE_RSA_WITH_AES_128_CBC_SHA] 
main, SEND TLSv1 ALERT: fatal, description = unexpected_message 
... 
main, WRITE: TLSv1 Alert, length = 32 
main, Exception sending alert: java.net.SocketException: Software caused connection abort: socket write error 
main, called closeSocket() 

3）服务器日志（略）

[info] [client x.x.x.x] Connection to child 1 established (server XXX:443) 
[info] Seeding PRNG with 0 bytes of entropy 
[debug] ssl_engine_kernel.c(1866): OpenSSL: Handshake: start 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: before/accept initialization 
[debug] ssl_engine_io.c(1897): OpenSSL: read 11/11 bytes from BIO#82f6820 [mem: 82c5290] (BIO dump follows) 
[debug] ssl_engine_io.c(1830): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_io.c(1869): | 0000: XX XX XX XX XX XX XX XX-XX XX XX     ...........  | 
[debug] ssl_engine_io.c(1875): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_io.c(1897): OpenSSL: read 245/245 bytes from BIO#82f6820 [mem: 82c529b] (BIO dump follows) 
[debug] ssl_engine_io.c(1830): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_io.c(1869): | 0000: XX XX XX XX XX XX XX XX-XX XX XX XX XX XX XX XX ................ | 
... 
[debug] ssl_engine_io.c(1869): | 00f0: XX XX XX XX XX         .....   | 
[debug] ssl_engine_io.c(1875): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_kernel.c(1987): [client x.x.x.x] SSL virtual host for servername XXX found 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 read client hello A 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 write server hello A 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 write certificate A 
[debug] ssl_engine_kernel.c(1274): [client x.x.x.x] handing out temporary 1024 bit DH key 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 write key exchange A 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 write certificate request A 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 flush data 
[debug] ssl_engine_io.c(1897): OpenSSL: read 5/5 bytes from BIO#82f6820 [mem: 82c5290] (BIO dump follows) 
[debug] ssl_engine_io.c(1830): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_io.c(1869): | 0000: 16 03 01 00 8d         .....   | 
[debug] ssl_engine_io.c(1875): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_io.c(1897): OpenSSL: read 141/141 bytes from BIO#82f6820 [mem: 82c5295] (BIO dump follows) 
[debug] ssl_engine_io.c(1830): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_io.c(1869): | 0000: XX XX XX XX XX XX XX XX-XX XX XX XX XX XX XX XX ................ | 
... 
[debug] ssl_engine_io.c(1869): | 0080: XX XX XX XX XX XX XX XX-XX XX XX XX XX   ............. | 
[debug] ssl_engine_io.c(1875): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_kernel.c(1884): OpenSSL: Write: SSLv3 read client certificate B 
[debug] ssl_engine_kernel.c(1903): OpenSSL: Exit: error in SSLv3 read client certificate B 
[debug] ssl_engine_kernel.c(1903): OpenSSL: Exit: error in SSLv3 read client certificate B 
[info] [client x.x.x.x] SSL library error 1 in handshake (server XXX:443) 
[info] SSL Library Error: 336105671 error:140890C7:SSL routines:SSL3_GET_CLIENT_CERTIFICATE:peer did not return a certificate No CAs known to server for verification? 
[info] [client x.x.x.x] Connection closed to child 1 with abortive shutdown (server XXX:443) 

在良好的情况下，我们始终没有看到 “*** CertificateRequest” 在客户端和这样输出的服务器上

[debug] ssl_engine_kernel.c(1987): [client x.x.x.x] SSL virtual host for servername XXX found 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 read client hello A 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 write server hello A 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 write certificate A 
[debug] ssl_engine_kernel.c(1274): [client x.x.x.x] handing out temporary 1024 bit DH key 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 write key exchange A 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 write server done A 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 flush data 
[debug] ssl_engine_io.c(1897): OpenSSL: read 5/5 bytes from BIO#82d82d8 [mem: 82c8790] (BIO dump follows) 
[debug] ssl_engine_io.c(1830): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_io.c(1869): | 0000: 16 03 01 00 86         .....   | 
[debug] ssl_engine_io.c(1875): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_io.c(1897): OpenSSL: read 134/134 bytes from BIO#82d82d8 [mem: 82c8795] (BIO dump follows) 
[debug] ssl_engine_io.c(1830): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_io.c(1869): | 0000: XX XX XX XX XX XX XX XX-XX XX XX XX XX XX XX XX ................ | 
... 
[debug] ssl_engine_io.c(1869): | 0080: XX XX XX XX XX XX        ......   | 
[debug] ssl_engine_io.c(1875): +-------------------------------------------------------------------------+ 
[debug] ssl_engine_kernel.c(1874): OpenSSL: Loop: SSLv3 read client key exchange A 

Java客户端代码大纲：

URL url = new URL("https://..."); 
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection(); 
connection.setRequestProperty("Authorization", "Basic " + DatatypeConverter.printBase64Binary((user + ":" + pass).getBytes(Charset.forName("UTF-8")))); 
connection.setReadTimeout(60*1000); 
connection.setUseCaches(false); 
connection.connect(); 

与

java -Djavax.net.ssl.trustStore=... -Djavax.net.ssl.trustStoreType=jks -Djavax.net.ssl.trustStorePassword=... -Djavax.net.debug=all ... 

问题运行：

1. 是什么让服务器发送证书请求，在客户端上引起 输出中 “*** CertificateRequest”？
2. 设置“SSLVerifyClient none”是否阻止证书请求？
3. 关于接下来看什么的任何建议？

更新：我注意到，当使用Java 6时，Java客户端从不显示错误。 Java 7和8以及Chrome，Internet Explorer和Firefox都会出现问题。这似乎指向TLSv1.1或TLSv1.2的问题（另请参阅https://serverfault.com/questions/513961/how-to-disable-tls-1-1-1-2-in-apache“OpenSSL v1.0.1在TLSv1.2中存在一些已知问题”）。我将尽力至少检查在Java客户端中禁用TLSv1.1/2是否会导致问题消失。

Answer 1

是什么让服务器发送证书请求，导致客户端输出“*** CertificateRequest”？

在服务器上调用SSL_CTX_set_client_CA_list。它是一个可分辨名称的列表。另请参阅SSL_CTX_set_client_CA_list man page。

服务器还需要拨打SSL_CTX_load_verify_locations在CA中建立信任。另见SSL_CTX_load_verify_locations man page。

---

是设置 “SSLVerifyClient无” 不会阻止证书请求？

可能。从SSL_CTX_set_verify man page开始，您需要SSL_VERIFY_PEER并可能需要SSL_VERIFY_FAIL_IF_NO_PEER_CERT。

---

什么就看未来有什么建议？

您应该显示相关的Java代码。

您应该声明服务器和客户端使用的OpenSSL版本。

Answer 2

是什么让服务器发送证书请求，导致客户端输出“*** CertificateRequest”？

某处你有SSLVerifyClient设置为“可选”或更高，可能在.htaccess文件，这就是为什么你不能在配置文件中找到它。这将覆盖全局设置的“SSLVerifyClient none”。

Answer 3

经过漫长而乏味的调试和分析，我想报告调查结果。该问题与客户端发送的TLS握手的第一个ClientHello消息有关。

Java 7和Java 8客户端（也可能是所有现代浏览器）都使用“服务器名称指示”（SNI）扩展名。只有使用此扩展时才会出现此问题。 Java 6客户端不会发送它，并且问题从未发生过。 TLSv1和TLSv1.2出现问题 - 我们从未观察到TLSv1.1请求，因此我无法发表评论。

对于Java 7和8客户端来说，我们可以设置-Djsse.enableSNIExtension=false来阻止客户端发送SNI扩展。

我们将尝试更改httpd.conf配置（以及包含的文件）以查看我们是否可以使服务器正常运行。如果我们成功，我可能会发布信息，例如，如果有服务器端解决方法。上面提到的Java开关是一种客户端解决方法，它至少足以满足我们每晚的构建。