Add support for single character reads as fallback for STARTTLS

[typingArtist]

Reading text for STARTTLS has moved into a separate function. The function handles switching between the modes (line-based vs. character-based reading) autonomously.

Fixes #731

This PR is based on #730.

[drwetter]

Thx @typingArtist .

You have a test host for me (tarpit) (dm/pm/whatsover)?

[drwetter]

0. It's a cool idea!

1. doesn't fly yet, seems to hang at SSLv3 'reading server hello... \nTLS message fragments:'

2. debugging info seems to be different if it is a tarpit host, i.e. if first line read in starttls_read_one_line() fails

3. testssl.sh uses double square brackets as single ones are an external command (try which ] in bash)

Cheers, Dirk

[drwetter]

Hi @typingArtist ,

I would like to close this for housekeeping reasons: As said it's a good idea but would need a bit of work. last but not least the branch you tried to patch against (2.9dev), is dead.

[typingArtist]

Ah, I have completely forgotten about that. Would you accept fixes rebased on current dev branch?

Also, what shall we do about testing? I see two options here:

1. Create a permanent public server for the sole purpose of tarpit testing
2. Create a temporary server-like local thread that simulates a tarpit STARTTLS server

I’d like to go with option 2 but I first have to learn about Perl testing anyway.

[drwetter]

Ah, I have completely forgotten about that. Would you accept fixes rebased on current dev branch?

No prob. There's no current dev branch :-) After release (or shortly before) of 3.0 there will be a 3.1dev branch

Create a temporary server-like local thread that simulates a tarpit STARTTLS server

I’d like to go with option 2 but I first have to learn about Perl testing anyway.

2. sounds fine to me. But I don't expect to write a unit test for that rare species. It's ok if we have something to test against.

OT: In general (@ all) unit tests are documented here and if one looks a existing scripts that should suffice.

Ok to close the PR and you resubmit when 3.1dev is there?

[typingArtist]

Sure. I do.