RFC 7633 introduces the TLS Features certificate extension, which contains "Features:
> The object member "Features" is a sequence of TLS extension identifiers (features, in this specification's terminology) as specified in the IANA Transport Layer Security (TLS) Extensions registry. If these features are requested by the client in its ClientHello message, then the server MUST return a ServerHello message that satisfies this request.
The main purpose of this certificate extension is to implement "must staple." If the extension is present in a TLS server's certificate and it includes status_request, then the server MUST include a stapled OCSP response if the client requests one. (The same applies for the status_request_v2 extension.)
This PR adds a check to `certificate_info()` of whether the server supports must staple (i.e., whether its certificate includes a TLS Features extension with "status_request"). It also changes the output for "OCSP stapling" in the case that the server did not staple an OCSP response. It indicates that:
* it is a critical issue if the certificate specifies "must staple"
* it is a low severity issue if the certificate does not specify "must staple," but the certificate does include an OCSP URI.
* it is not an issue at all if the certificate does not specify "must staple" and certificate does not include an OCSP URI.
`run_server_preference()` prints out the server's Negotiated cipher in a different color depending on the quality of the cipher. However, there is a "FIXME" since CBC ciphers are supposed to be flagged, but it is not easy to identity all CBC ciphers from their OpenSSL names.
This PR partially addresses this. It creates a separate function for printing a cipher based on its quality. Whenever possible it determines the quality of the cipher based on the RFC name. However, if it is provided an OpenSSL name and no cipher-mapping.txt file is available, it will follow the current (imperfect) logic for determining the cipher's quality.
The function also returns a value that indicates the quality of the cipher provided, with higher numbers indicating better ciphers. This return value is used by `run_server_preference()` to determine how to populate the "severity" field when calling `fileout()`.
In the case that `tls_sockets()` is being used and the server incorrectly fails the connection rather than downgrading, testssl.sh is printing "not offered" on one line and then the error message on the next line, but all the text should appear on one line (as it does when testing TLS 1 and TLS 1.1).
Since the test for TLS 1.2 in `run_protocols()` now uses `tls_sockets()` whenever `$ssl_native` is `true` (i.e., there is no longer a requirement for `$EXPERIMENTAL` to be true as well), the `$EXPERIMENTAL` flag should no longer be checked if the return value is 1.
When a list of cipher suites is being displayed using `neat_list()`, testssl.sh shows the cipher suite's OpenSSL name and (in most cases) the RFC name as well. However, in all other cases only the OpenSSL name is shown.
This PR adds the option to have cipher suite's RFC names shown instead of the OpenSSL name, by including `--mapping rfc` in the command line. [Note: if the cipher-mapping.txt file cannot be found, then the `--mapping rfc` option is ignored and the OpenSSL names are shown.]
This PR seems to be related to issue #9, but #9 may be been referring to the output created by `neat_list()`.
This PR addresses the issue raised in #623. This PR is based on the function `out_row_aligned_max_width()` that I proposed in #623, but the `out_row_aligned_max_width()` in this PR is a little different. It takes a fourth parameter, which is the function to use to print each word in the text string to be printed. This is used in `run_pfs()` so that the "Elliptic curves offered" can be printed using this function (some servers support 25 curves), while still having the curves printed using color-coding to indicate the quality of each curve.
I somewhat arbitrarily have each line wrap at 120 characters, but that could be changed (e.g., to `$TERM_WIDTH`).
