curl去訪問https的站點報錯：
curl -v https://www.baidu.com
* SSLv3, TLS handshake, Client hello (1):
* SSLv3, TLS handshake, Server hello (2):
* SSLv3, TLS handshake, CERT (11):
* SSLv3, TLS alert, Server hello (2):
* SSL certificate problem: unable to get local issuer certificate
curl: (60) SSL certificate problem: unable to get local issuer certificate
More details here: http://curl.haxx.se/docs/sslcerts.html
curl performs SSL certificate verification by default, using a "bundle"
of Certificate Authority (CA) public keys (CA certs). If the default
bundle file isn't adequate, you can specify an alternate file
using the --cacert option.
If this HTTPS server uses a certificate signed by a CA represented in
the bundle, the certificate verification probably failed due to a
problem with the certificate (it might be expired, or the name might
not match the domain name in the URL).
If you'd like to turn off curl's verification of the certificate, use
the -k (or --insecure) option.
看了一下curl是支持ssl的
curl -V
curl 7.29.0 (mipsel-openwrt-linux-gnu) libcurl/7.29.0 OpenSSL/1.0.1e zlib/1.2.7
Protocols: file ftp ftps http https imap imaps pop3 pop3s rtsp smtp smtps tftp
Features: IPv6 Largefile NTLM NTLM_WB SSL libz TLS-SRP
curl的命令也是支持的
curl -h|grep ssl
--ftp-ssl-ccc Send CCC after authenticating (F)
--ftp-ssl-ccc-mode ACTIVE/PASSIVE Set CCC mode (F)
--ftp-ssl-control Require SSL/TLS for ftp login, clear for transfer (F)
--ssl Try SSL/TLS (FTP, IMAP, POP3, SMTP)
--ssl-reqd Require SSL/TLS (FTP, IMAP, POP3, SMTP)
-2, --sslv2 Use SSLv2 (SSL)
-3, --sslv3 Use SSLv3 (SSL)
--ssl-allow-beast Allow security flaw to improve interop (SSL)
覺得很奇怪啊，爲啥報錯，仔細看了一下報錯信息：unable to get local issuer certificate。原來是找不到本地的證書。找了找本地確實沒有證書，尷尬。
並且錯誤提示裏面給了證書下載地址：
http://curl.haxx.se/docs/sslcerts.html
找到證書下載地址：
https://curl.haxx.se/ca/cacert.pem
下載成功後，放到板子上，我是放在這個路徑下了
/etc/curlssl/cacert.pem
然後配置到環境變量
export CURL_CA_BUNDLE=/etc/curlssl/cacert.pem
然後訪問下百度：
curl -v https://www.baidu.com
* SSLv3, TLS handshake, Client hello (1):
* SSLv3, TLS handshake, Server hello (2):
* SSLv3, TLS handshake, CERT (11):
* SSLv3, TLS handshake, Server finished (14):
* SSLv3, TLS handshake, Client key exchange (16):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
> GET / HTTP/1.1
> User-Agent: curl/7.29.0
> Host: www.baidu.com
> Accept: */*
>
< HTTP/1.1 200 OK
< Accept-Ranges: bytes
< Cache-Control: private, no-cache, no-store, proxy-revalidate, no-transform
< Connection: Keep-Alive
< Content-Length: 2443
< Content-Type: text/html
< Date: Mon, 25 Mar 2019 03:18:39 GMT
< Etag: "588603ec-98b"
< Last-Modified: Mon, 23 Jan 2017 13:23:56 GMT
< Pragma: no-cache
< Server: bfe/1.0.8.18
< Set-Cookie: BDORZ=27315; max-age=86400; domain=.baidu.com; path=/
<
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