Parsing a CSR that has a wilcard CN with no SAN raises an exception

[Just1uke]

• What did you do?

Attempted to parse a CSR that had a wildcard as the CN, but no SAN.

• What did you expect to happen?

Details for the CSR to be parsed out correctly.

• What happened instead?

undefined method `value' for nil:NilClass
/gems/r509-0.10.0/lib/r509/csr.rb:204:in `block in parse_san_attribute_from_csr'"
/gems/r509-0.10.0/lib/r509/csr.rb:201:in `each'"
/gems/r509-0.10.0/lib/r509/csr.rb:201:in `parse_san_attribute_from_csr'"
/gems/r509-0.10.0/lib/r509/csr.rb:184:in `parse_csr'"
/gems/r509-0.10.0/lib/r509/csr.rb:71:in `initialize'"

Example CSR:

-----BEGIN CERTIFICATE REQUEST-----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-----END CERTIFICATE REQUEST-----

Code to raise exception:

cert = R509::CSR.new(csr: params[:csr].strip)

Test:

    it "works when the CN is a wildcard with no SAN" do
      csr = R509::CSR.new(:csr => @csr_wildcard_cn_no_san)
      expect(csr.subject_component('CN').to_s).to eq('*.local')
      expect(csr.san).to be_nil
    end