It would seem like the PR #11623 had chewed more
than it wanted to, non-fips build shouldn't really
be forced to use slower crypto/sha256 even for
presumed "non-performance" codepaths. In MinIO
there are really no "non-performance" codepaths.
This assumption seems to have had an adverse
effect in certain areas of CPU usage.
This PR ensures that we stick to sha256-simd
on all non-FIPS builds, our most common build
to ensure we get the best out of the CPU at
any given point in time.
This commit replaces the usage of
github.com/minio/sha256-simd with crypto/sha256
of the standard library in all non-performance
critical paths.
This is necessary for FIPS 140-2 compliance which
requires that all crypto. primitives are implemented
by a FIPS-validated module.
Go can use the Google FIPS module. The boringcrypto
branch of the Go standard library uses the BoringSSL
FIPS module to implement crypto. primitives like AES
or SHA256.
We only keep github.com/minio/sha256-simd when computing
the content-SHA256 of an object. Therefore, this commit
relies on a build tag `fips`.
When MinIO is compiled without the `fips` flag it will
use github.com/minio/sha256-simd. When MinIO is compiled
with the fips flag (go build --tags "fips") then MinIO
uses crypto/sha256 to compute the content-SHA256.