This PR changes run_rc4() to correctly handle SSLv2 ciphers.
It addresses the problem in which servers that do not implement SSLv2, but that implement SSLv3 ciphers that share an OpenSSL name with an SSLv2 cipher (RC4-MD5 and EXP-RC4-MD5), are not incorrectly shown as having implemented the SSLv2 cipher.
It also addresses the problem that if a server does implement SSLv2 with an RC4 SSLv2-cipher suite, then that cipher suite it not shown as being implemented.
It is OK for a site to pin a CA that is not part of the chain (like github.com does)
This is a provision against a CA compromise (like diginotar) which could lead to a
briked site in case of CA compromise.
GitHub has built in multiple levels of security they have both backup pins for host
certs and back pins for CAs (and I wouldn;t be surprised if they have a backup
intermediate pin too).
`certificate_info()` does not correctly display the Issuer name for CAs that use domain component attributes.
There is a server on the NIST intra-net that I test against that has a certificate issued by a NIST CA, and the issuer name in the certificate is of the form: `/DC=net/DC=example/DC=internal/CN=CAname`
Since there is no organizational name, testssl.sh displays the name as:
```
Issuer "CAname" ("")
```
In this PR, if the Issuer name has 'DC=' attributes, but does not have an 'O=' attribute, the "DC=" attributes are combined into a DNS name that is used as if it were the organizational name:
```
Issuer "CAname" ("internal.example.net")
```
I should note, however, that I have not been able to find any other examples of TLS server certificates that have been issued by CAs that have domain components ("DC=") in their names. So, it may not be worthwhile to change the code to try to accommodate such CAs.
`certificate_info()` currently outputs `$issuer` to the JSON file, where is should be outputting `$issuer_CN` in order for the information in the JSON file to match the information that is displayed.
This PR also fixes the problem that if an Issuer name contains a domain component attribute (DC=) then it will be mistakenly treated as a country attribute (C=).
Rather than try each curve one at a time, follow model in `cipher_pref_check()`. First include all curves in ClientHello, then successively remove from the ClientHello those curves that have been offered by the server until the connection fails. This makes the number of calls to `$OPENSSL s_client` one more than the number of supported curves rather than the number of curves in NamedCurve supported by $OPENSSL.
Note, however, that OpenSSL defines MAX_CURVELIST as 28 and fails if the `-curves` option includes more than 28 curves. Since OpenSSL 1.1.0 offers 29 curves from NamedCurve, this PR breaks the list of supported curves in 2. At the cost of one additional calls to `$OPENSSL s_client` it ensures that the number of curves provides to the `-curves` option is below the limit.
David Cooper
Dirk Wetter
Frank Breedijk
Thomas Patzke