PHP cURL 和 SSL 的奇怪超时

当我尝试访问 Amazon Cloudfront 时，将 cURL 与 PHP 结合使用时遇到奇怪的超时。这似乎会影响所有失效请求、创建发行版等。cURL 要么报告接收到 0 字节，要么报告接收到很少的字节，然后超时：Operation timed out after 120000 milliseconds with 88 out of 619 bytes received.

延长超时设置似乎没有什么区别。

使用进行跟踪CURLOPT_VERBOSE产生这个输出：

* About to connect() to cloudfront.amazonaws.com port 443 (#0)
*   Trying 72.21.215.67... * connected
* Connected to cloudfront.amazonaws.com (72.21.215.67) port 443 (#0)
* skipping SSL peer certificate verification
* SSL connection using SSL_RSA_WITH_RC4_128_MD5
* Server certificate:
*   subject: CN=cloudfront.amazonaws.com,O=Amazon.com Inc.,L=Seattle,ST=Washington,C=US
*   start date: Jul 30 00:00:00 2010 GMT
*   expire date: Jul 29 23:59:59 2013 GMT
*   common name: cloudfront.amazonaws.com
*   issuer: CN=VeriSign Class 3 Secure Server CA - G2,OU=Terms of use at https://www.verisign.com/rpa (c)09,OU=VeriSign Trust Network,O="VeriSign, Inc.",C=US
> POST /2010-11-01/distribution/E1CIM4A92QFD98/invalidation HTTP/1.1
User-Agent: S3/php
Accept: */*
Host: cloudfront.amazonaws.com
Date: Wed, 07 Mar 2012 14:31:58 GMT
Content-Type: application/xml
Authorization: AWS ************************
Content-Length: 200

< HTTP/1.1 201 Created
< x-amzn-RequestId: 4c2d0d3f-6862-11e1-ac27-5531ac8c967f
< Location: https://cloudfront.amazonaws.com/2010-11-01/distribution/E1CIM4A92QFD98/invalidation/I35KLNROKA40FU
* Operation timed out after 120000 milliseconds with 0 bytes received
* Closing connection #0

这看起来类似于这个问题 https://stackoverflow.com/q/2950417/305019。然而，在我的例子中，curl 实际上确实得到了响应，但不知何故忽略了它并超时了？据我所知，收到了回复（201 Created...)，并且没有 SSL 错误。那么为什么curl会超时呢？

cURL 版本信息

[version_number] => 463623 
[age] => 3 
[features] => 1597 
[ssl_version_number] => 0 
[version] => 7.19.7 
[host] => x86_64-unknown-linux-gnu 
[ssl_version] => NSS/3.12.7.0 
[libz_version] => 1.2.3 
[protocols] => Array ( [0] => tftp [1] => ftp [2] => telnet [3] => dict [4] => ldap [5] => ldaps [6] => http [7] => file [8] => https [9] => ftps [10] => scp [11] => sftp )

仍然不完全确定为什么这个版本的curl会这样（看起来像一个bug），但解决方案是编译不同版本的curl和php（或多或少遵循这些说明 http://community.webfaction.com/questions/7959/how-did-i-install-my-own-phpcurlopenssl-for-use-with-the-shared-web-server)