bpo-38684: haslib: fix build when Blake2 not enabled in OpenSSL

[commodo]

This was caught via OpenWrt's build, when upgrading to 3.8.
By default, Blake2 is not enabled in OpenWrt's OpenSSL.
Not sure if this is an issue in OpenSSL or Python or both.

After digging through the _hashopenssl.c, it seems that the check for
Blake2 being enabled/present in OpenSSL is not consistent with how OpenSSL
does it.

I guess this issue happens when Blake2 is present, but not enabled.
While the previous code was checking whether it is present.

Error is:

Modules/_hashopenssl.c:220:22: error: implicit declaration of function 'EVP_blake2s256'; did you mean 'SN_blake2s256'? [-Werror=implicit-function-declaration]
             digest = EVP_blake2s256();
                      ^~~~~~~~~~~~~~
                      SN_blake2s256
Modules/_hashopenssl.c:220:20: warning: assignment to 'const EVP_MD *' {aka 'const struct evp_md_st *'} from 'int' makes pointer from integer without a cast [-Wint-conversion]
             digest = EVP_blake2s256();
Modules/_hashopenssl.c:223:22: error: implicit declaration of function 'EVP_blake2b512'; did you mean 'LN_blake2b512'? [-Werror=implicit-function-declaration]
             digest = EVP_blake2b512();
                      ^~~~~~~~~~~~~~
Modules/_hashopenssl.c:223:20: warning: assignment to 'const EVP_MD *' {aka 'const struct evp_md_st *'} from 'int' makes pointer from integer without a cast [-Wint-conversion]
             digest = EVP_blake2b512();
                    ^

Signed-off-by: Alexandru Ardelean [email protected]

https://bugs.python.org/issue38684

[tiran]

I'm sure this is not compatible with OpenSSL 1.1.0 and 1.0.2. You need to check for both the presence of NID-blake2b512 and absence of OPENSSL_NO_BLAKE2.

[bedevere-bot]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[commodo]

I'm sure this is not compatible with OpenSSL 1.1.0 and 1.0.2. You need to check for both the presence of NID-blake2b512 and absence of OPENSSL_NO_BLAKE2.

good point;
i hadn't thought of that;

[commodo]

Changelog v1 ->v2:

• change check for Blake2 from #ifdef NID_blake2b512 -> #if defined(NID_blake2b512) && !defined(OPENSSL_NO_BLAKE2)

[tiran]

Thanks!

[bedevere-bot]

@tiran: Please replace # with GH- in the commit message next time. Thanks!

[miss-islington]

Thanks @commodo for the PR, and @tiran for merging it 🌮🎉.. I'm working now to backport this PR to: 3.8.
🐍🍒⛏🤖

[bedevere-bot]

GH-17044 is a backport of this pull request to the 3.8 branch.