crypto/tls: Add support for SHA256 CBC ciphers

[fatmcgav]

I am currently attempting to use Golang v1.6 to interact with a 3rd party WS API.

Currently, they have a very limited set of supported ciphers:

• TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
• TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
• TLS_RSA_WITH_AES_128_CBC_SHA256

Unfortunately none of these overlap with supported Go's supported ciphers. Therefore I just get an 'EOF' response currently.

Putting it out on the golang-nuts mailing list, I got a response from Phus Lu which included a commit that adds the following ciphers:

• TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
• TLS_RSA_WITH_AES_128_CBC_SHA256
• TLS_RSA_WITH_AES_256_CBC_SHA256

Is there appetite to add support for these cipher suites to core?

[phuslu]

There're more and more TLSv1.2-only servers in these days.
Hopefully go could have full TLSv1.2 ciphers support in future releases.

[gopherbot]

CL https://golang.org/cl/27315 mentions this issue.

[gopherbot]

CL https://golang.org/cl/35290 mentions this issue.