[Pkg-openssl-devel] Bug#1011076: libssl3, mercurial: can't connect to server created with `openssl s_server -tls1`

[Sebastian Andrzej Siewior]

On 2022-05-16 17:15:29 [+0200], Julien Cristau wrote:
> Hi,
Hi,

> The failures happen in parts of the test that spin up and attempt to
> connect to a TLS1.0 or TLS1.1 server.  It used to pass on 1.1.1n and (I
> think) 1.1.1o.

That is something I don't understand.

> Trying to replicate with openssl's cmdline tools, e.g.:
>   openssl s_server -cert tests/sslcerts/pub.pem -key tests/sslcerts/priv.pem -tls1
> 
> and
>   openssl s_client -connect localhost:4433 -tls1
> 
> The server reports:
> 4084745F427F0000:error:0A000076:SSL routines:tls_choose_sigalg:no suitable signature algorithm:../ssl/t1_lib.c:3331:
> 
> Talking with Sebastian on IRC he suggested some extra -cipher /
> -provider command line options which didn't seem to make a difference.

You need to use -cipher "ALL:@SECLEVEL=0" instead of 1.

> I guess I have two questions:
> - is this a bug or an intended change?
> - if it's intended, is there a way to allow these connections again?

As per https://www.openssl.org/docs/man3.0/man7/migration_guide.html:
| The security strength of SHA1 and MD5 based signatures in TLS has been reduced.

that is why 0 is required instead of 1 as I suggested earlier. The
paragraph goes on:
| The security level can be changed either using the cipher string with
| @SECLEVEL, or calling SSL_CTX_set_security_level(3).

Hope that helps.

> Thanks,
> Julien

Sebastian