Re: [OE-core] [yocto-security] [PATCH] openssl: drop support for deprecated algorithms

["Richard Purdie" <richard.purdie@linuxfoundation.org>]

On Sat, 2020-12-19 at 19:04 +0100, Konrad Weihmann wrote:
> 
> On 19.12.20 18:58, Richard Purdie wrote:
> > On Sat, 2020-12-19 at 18:53 +0100, Konrad Weihmann wrote:
> > > On 19.12.20 18:36, Richard Purdie wrote:
> > > >    PACKAGECONFIG[cryptodev-linux] = "enable-devcryptoeng,disable-devcryptoeng,cryptodev-linux,,cryptodev-module"
> > > > +PACKAGECONFIG[no-tls1] = "no-tls1"
> > > > +PACKAGECONFIG[no-tls1_1] = "no-tls1_1"
> > > >    
> > > >    B = "${WORKDIR}/build"
> > > >    do_configure[cleandirs] = "${B}"
> > > > @@ -52,6 +54,10 @@ EXTRA_OECONF_class-nativesdk = "--with-rand-seed=os,devrandom"
> > > >    CFLAGS_append_class-native = " -DOPENSSLDIR=/not/builtin -DENGINESDIR=/not/builtin"
> > > >    CFLAGS_append_class-nativesdk = " -DOPENSSLDIR=/not/builtin -DENGINESDIR=/not/builtin"
> > > >    
> > > > +# Disable deprecated crypto algorithms
> > > > +# Retained for compatibilty - des (curl), dh (python-ssl), dsa (rpm)
> > > > +DEPRECATED_CRYPTO_FLAGS = " no-ssl no-idea no-psk no-rc2 no-rc4 no-rc5 no-md2 no-md4 no-srp no-camellia no-bf no-mdc2 no-scrypt no-seed no-siphash no-sm2 no-sm3 no-sm4 no-whirlpool"
> > > > +
> > >   From my perspective this breaks backward compatibility, so I would
> > > rather have them all that as optional PACKAGECONFIG fields (which also
> > > does make it easier for ppl, still relying on one of those algorithms,
> > > for whatever reason, to re-enable them) - with the current approach all
> > > one could do is to override it with a bbappend - and tbh letting ppl
> > > have bbappends for this recipe, doesn't sound like the best idea in the
> > > long run to "enforce" any kind of "security" or "hardening"
> > 
> > Having it as a variable does mean you could customise the variable and
> > doesn't mean it has to be done with a bbappend, it can be set from a
> > distro config too.
> > 
> > I'm not sure turning each one into a packageconfig is going to be more
> > helpful compared to this in practise...
> 
> I'm not sure I follow, as this is a "hard" assign - if it would (in 
> theory) a ??= assignment, yes then it would be fine. Still that leaves 
> us with a not commonly known variable, while PACKAGECONFIG is more 
> widely accepted in 3rd party layers/distros from my experience.

You could do various things to this from a distro config, e.g.:

DEPRECATED_CRYPTO_FLAGS_pn-openssl = "xxx"

or

DEPRECATED_CRYPTO_FLAGS_pn-openssl_<distrooverride> = "xxx"

DEPRECATED_CRYPTO_FLAGS_pn-openssl_append = " extra-disable"

DEPRECATED_CRYPTO_FLAGS_pn-openssl_remove = "add-me-back"

so I'd say that its not a particularly "hard" assignment?

We could make it a ??= but I'm not sure it would change much practcial
use as it would almost always be with an override of some sort?

Whilst PACKAGECONFIG is more well known,the variable name here may
actually improve readability...

Cheers,

Richard