> On 24 May 2021, at 03:29, Michael Paquier <mich...@paquier.xyz> wrote:
> I got to look at that in details, and the attached would be able to do > the job with OpenSSL 1.0.2 and older versions. The main idea is to > set up SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS once the SSL object is > created when opening the TLS connection to business. I have tested > that down to 0.9.8 on all supported branches with the protocols we > support (heads up to ssl_min_protocol_version here), and that looks to > work as I'd expect. > > It is not a good idea to rely on OPENSSL_VERSION_NUMBER for such > version checks as I am doing here, as we've been bitten with > compatibility with LibreSSL in the past. So this had better use a > check based on HAVE_OPENSSL_INIT_SSL to make sure that 1.1.0 is the > version of OpenSSL used. I agree that a capability based check is better than using the version numbers as their is a collision risk between distributions (and even within OpenSSL as NetBSD for example invented their own version etc). > Anyway, I really don't like using this undocumented option, and there is > nothing that can be done with OpenSSL < 1.1.0h in the 1.1.0 series as the s3 > part of the *SSL object gets hidden to the application, so it is not possible > to set SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS there. 1.1.0d killed what was left of SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS while keeping it defined, so there is also very little value in even attempting it there. +1 on the patch, LGTM. -- Daniel Gustafsson https://vmware.com/
