https://issues.apache.org/bugzilla/show_bug.cgi?id=53952
--- Comment #37 from Christopher Schultz <ch...@christopherschultz.net> --- I'm looking at Marcel's attachment #30150 and the protocol selection is a bit verbose though methodical. It took a bit of thinking to understand why the code does what it does. Specifically, it does not explicitly cover all possible combinations of values for "protocol". Instead, it takes a top-down approach assuming that the user will want the highest-available protocol to be supported. Checks for exact matches are performed for TLSv1.2, TLSv1.1, TLSv1(.0), SSLv3, and SSLv2 are performed and the client gets the requested version unless the library doesn't support that version, in which case the client gets an inert SSL engine. It's debatable whether or not this should throw some kind of error. After the exact checks, there are checks for "anything including TLSv1.2" and "anything including TLSv1.1", except that those checks are not even compiled if OpenSSL does not support them. (Of those, the highest protocol supported by the library is used.) Failing the above, SSL2/3 is selected. I see a consistency problem, here: if TLSv1.2 is not supported by OpenSSL but the client requests is specifically, then they will get an inert engine. If the client requests TLSv1.2 + SSLv3 and TLSv1.2 is not supported, they'll get the SSLv2/3 engine instead instead of the SSLv3 engine. It's not clear to me whether this was intentional. I will be committing attachment #30150 without modification and we can debate the correct behavior later. What's interesting (or awful: you decide) about OpenSSL is that you can't choose the exact set of protocols to support when choosing an engine method. Instead, you have to choose the engine method that makes the most sense (usually the highest version-number that is supported and requested by the client) and then you have to go back and black-list all the protocols that the selected method may support but that you don't want. A perfect case is that of requesting TLS1.2+TLS1.1 and nothing else. For that, you have to ask for the TLSv1.2 method in OpenSSL, but that method also provides TLS1, SSLv3, and SSLv2. So you have to call SSL_CTX_set_options and *enable* the *disable flags* for those other protocols. It's not straightforward at all and worth mentioning this to those who would like to review the patch. -- You are receiving this mail because: You are the assignee for the bug. --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For additional commands, e-mail: dev-h...@tomcat.apache.org
