Add "legacy", key and cert PBE alg options to openssl_pkcs12_export

[Furgas]

Description

Please consider adding support for forcing legacy mode for openssl_pkcs12_export. Currently the only workaround I know, is to switch completely to calling command line openssl pkcs12 -export directly with -legacy option, which requires enabling proc_open or other similar functions, which can pose security risk. Unfortunately many systems and applications still understands only legacy algorithms in PKCS#12 files so many are still forced to use them when creating PKCS#12 files.

[cmb69]

Isn't that already solved with the configure option --with-openssl-legacy-provider? And I think you don't even need that if you set up support for legacy providers in your openssl.conf, and have the legacy provider build as module (that's possible with PHP on Windows at least).

[Furgas]

Well, I'd rather use prebuild PHP packages that comes with the distribution, than compile it from source. I guess that it's not controversial. And I'm quite sure that enabling legacy provider doesn't force openssl_pkcs12_export to use them, as enabling legacy providers in openssl.conf is not enough - you have to provide -legacy option to openssl pkcs12 -export.

[cmb69]

Maybe @bukka can clarify.

[bukka]

@Furgas Ok I just did a bit of checking and I guess that you are actually asking about is an option or parameter to select different password base encryption algorithm (legacy flag in OpenSSL app selects NID_pbe_WithSHA1And3_Key_TripleDES_CBC) and not only the library default in PKCS12_create_ex2 (NID_aes_256_cbc) which PHP uses. Is that right?

[bukka]

Otherwise setting the provider should work via config so what's really missing is the key algorithm and there are few other options that might be useful to add as well.

[Furgas]

@bukka Yeah, on more general level it would be great to be able to precisely select private key and certifcate encryption algorithm (-keypbe and -certpbe options in openssl pkcs12) and maybe also MAC algorithm (-macalg option). It can be discussed if a legacy option should be then added as a "shortcut".

[bukka]

Yeah we could start with keypbe and certpbe. I just checked mecalg and it is used for extra info for fetching mac:

https://github.com/openssl/openssl/blob/c734897df9604a62be4a30845186865d5ca17d29/apps/pkcs12.c#L782-L794

So that is not currently applicable and we would need a new API for that. So something for the future maybe.

Otherwise we could consider legacyoption but I don't like this "legacy" naming and it's more just an app thing. It's worth considering though.