If `determine_tls_extensions()` does not create a temporary file (`$TEMPDIR/$NODEIP.determine_tls_extensions.txt`) then `run_server_defaults()` will display error messages when an attempt is made to copy this file or to search (grep) it. This may happen if `$OPTIMAL_PROTO` is `-ssl2` or if `determine_tls_extensions()` uses sockets and `parse_tls_serverhello()` encountered an error and did not create a temporary file (`$TEMPDIR/$NODEIP.parse_tls_serverhello.txt`). This PR fixes this by only trying to copy and search `$TEMPDIR/$NODEIP.determine_tls_extensions.txt` is `$OPTIMAL_PROTO` is not `-ssl2` and `determine_tls_extensions()` was successful (return value 0).
In response to your request in #572, this PR provides a starting point for addressing #120. It adds code to `run_logjam()` to try connecting to the server using any cipher that uses an ephemeral DH key. If successful, it gets the server's ephemeral key (in OpenSSL's PEM format) and then extracts the prime from the key and places it in `$dh_p`. So, all that needs to be done at this point is to compare `$dh_p` against a set of "bad" primes. I'm not sure if I'll be able to work on that part soon, so if someone else has the time, that would be great.
I actually found the `-msg` option easy to use. I moved the code in `parse_tls_serverhello()` that extracts the DH ephemeral public key from the ServerKeyExchange message into a separate function. Then, if using OpenSSL with the `-msg` option, I extract the ServerKeyExchange message from `$TMPFILE` and call this new function to extract the key and convert it to PEM format. That way the new code in `run_logjam()` can use either `$OPENSSL` or `tls_sockets()`.
This PR changes `run_http2()` so that it uses `tls_sockets()` rather than failing, if `$OPENSSL` does not support the `-alpn` option. If `$OPENSSL` supports the `-alpn` option (or if `$SSL_NATIVE` is true), then this PR has no effect.
This PR change `run_std_cipherlists()` to use sockets. As noted in isse #554, I have some questions about the definitions of the cipher lists, but I wrote the code so that the ciphers that are tested when using sockets are the same as those that are tested when using OpenSSL. For a few of the cipherlists, the sockets version tests a few additional ciphers; but these are ciphers that are not supported by OpenSSL, and whose definitions are consistent with the ciphers that OpenSSL includes.
As written, `std_cipherlists` will use sockets for testing by default, except in two cases:
* If the `$SSL_NATIVE` is true, then only OpenSSL is used, and if OpenSSL doesn't support any ciphers in the cipherlist, then the test is skipped.
* If `$FAST` is true (but `$SSL_NATIVE` is false), then OpenSSL is used whenever it supports at least one cipher from the cipherlist, and `tls_sockets()` (or `sslv2_sockets()`) is only used when OpenSSL doesn't support any ciphers from the cipherlist.