crypto: fix missing nullptr check on RSA_new()

[ndossche]

Not checking this can cause a null deref. Since there is already a null check at the bottom of the function with NewRSA().

Note: this was found by a static-dynamic analyser I'm developing.

[nodejs-github-bot]

Review requested:

• @nodejs/crypto

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 89.74%. Comparing base (4a13a62) to head (00b4cf8).
⚠️ Report is 41 commits behind head on main.

Files with missing lines	Patch %	Lines
src/crypto/crypto_rsa.cc	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61888      +/-   ##
==========================================
- Coverage   89.76%   89.74%   -0.02%     
==========================================
  Files         675      674       -1     
  Lines      204674   204809     +135     
  Branches    39330    39361      +31     
==========================================
+ Hits       183716   183808      +92     
- Misses      13235    13272      +37     
- Partials     7723     7729       +6     

Files with missing lines	Coverage Δ
src/crypto/crypto_rsa.cc	63.39% <0.00%> (-0.21%)	⬇️

... and 68 files with indirect coverage changes

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[addaleax]

Why does this not throw an exception like the other return {}; sites?

[ndossche]

I was confused about the exception handling. Line 438 with the EVPKeyPointer::NewRSA also does not do any exception throwing. Yet when I forced this rsa check to fail at this line during testing I did get an exception when running some tests using ./tools/test.py.