“error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed”解决方法

使用git通过https方式从github clone git repo源码时，报错如下：

Cloning into  'git' ...
fatal: unable to access  'https://github.com/git/git.git/' : SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

开启curl verbose选项（用于调试）并重新执行git clone，详细报错信息：

$  export  GIT_CURL_VERBOSE=1
$ git clone https: //github .com /git/git .git
Cloning into  'git' ...
* Couldn't  find  host github.com  in  the .netrc  file , using defaults
* About to connect() to github.com port 443
*   Trying 192.30.252.128... * connected
* Connected to github.com (192.30.252.128) port 443
* successfully  set  certificate verify locations:
*   CAfile:  /usr/share/ssl/certs/ca-bundle .crt
  CApath: none
* SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
* Closing connection  #0
fatal: unable to access  'https://github.com/git/git.git/' : SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

 从错误提示可知，git通过curl访问https地址时，未能在本机未找到ca证书，从而导致ssl certificate verify failed。

解决方法：

Setp1：从curl官网下载cacert.pem文件（下载链接参见这里，关于curl的Server SSL Certificates细节参见这里，其中提到，从curl 7.18.0开始，编译安装curl时默认安装ca证书，而我机器的curl version=7.12.1，curl –version可查看）：

 ~$ mkdir ~/tools/https-ca
 ~$ cd ~/tools/https-ca
 ~$ curl http: //curl.haxx.se/ca/cacert.pem -o cacert.pem

Step2：终端执行下面的命令，以便为git配置ca认证信息： 

 ~$ git config --global http.sslCAInfo  /home/slvher/tools/https-ca/cacert .pem

可打开~/.gitconfig确认cainfo配置成功写入git配置文件

        完成以上两步后，执行git clone https://github.com/git/git.git成功，问题解决。

【参考资料】

1. StackOverflow: SSL certificate rejected trying to access GitHub over HTTPS behind firewall

2. cURL: Details on Server SSL Certificates