Alias OpenSSL SECLEVEL directives to ALL

[WillChilds-Klein]

Issues:

Addresses CryptoAlg-2792

Description of changes:

To increase compatibility with OpenSSL's notion of "security levels", this commit aliases all security levels ≤ 2 to AWS-LC's ALL alias. Described here, OpenSSL's security level 0 provides no minimum.

Testing:

• CI with reduced CPython patch set

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[samuel40791765]

Just to give some more context, I initially set our default security level to 3 under the same justifications. However, I had to change the value to 0 later on because we don't directly prohibit 512 bit RSA keys like OpenSSL states with Level 1..
This commit has more details: 42cd981

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 78.75%. Comparing base (c0e927e) to head (c1aa1e9).

Files with missing lines	Patch %	Lines
ssl/ssl_cipher.cc	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2065      +/-   ##
==========================================
- Coverage   78.75%   78.75%   -0.01%     
==========================================
  Files         598      598              
  Lines      103651   103651              
  Branches    14721    14718       -3     
==========================================
- Hits        81632    81630       -2     
- Misses      21366    21369       +3     
+ Partials      653      652       -1     

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[WillChilds-Klein]

Thanks for the context @samuel40791765.

However, I had to change the value to 0 later on because we don't directly prohibit 512 bit RSA keys

Do you mean for parsing or generating?

I believe we enforce minimum of 2048 bits in FIPS mode, but looking around a bit, I do see a surprisingly low minimum key size threshold of 256 bits. Given this, I agree that we should only honor SECLEVEL=0.