41 lines
1.6 KiB
Ruby
41 lines
1.6 KiB
Ruby
# frozen_string_literal: true
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require 'openssl'
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module Gitlab
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module Email
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module Smime
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# Tooling for signing and verifying data with SMIME
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class Signer
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# The `ca_certs` parameter, if provided, is an array of CA certificates
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# that will be attached in the signature together with the main `cert`.
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# This will be typically intermediate CAs
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def self.sign(cert:, key:, ca_certs: nil, data:)
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signed_data = OpenSSL::PKCS7.sign(cert, key, data, Array.wrap(ca_certs), OpenSSL::PKCS7::DETACHED)
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OpenSSL::PKCS7.write_smime(signed_data)
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end
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# Return nil if data cannot be verified, otherwise the signed content data
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#
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# Be careful with the `ca_certs` parameter, it will implicitly trust all the CAs
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# in the array by creating a trusted store, stopping validation at the first match
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# This is relevant when using intermediate CAs, `ca_certs` should only
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# include the trusted, root CA
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def self.verify_signature(ca_certs: nil, signed_data:)
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store = OpenSSL::X509::Store.new
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store.set_default_paths
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Array.wrap(ca_certs).compact.each { |ca_cert| store.add_cert(ca_cert) }
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signed_smime = OpenSSL::PKCS7.read_smime(signed_data)
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# The S/MIME certificate(s) are included in the message and the trusted
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# CAs are in the store parameter, so we pass no certs as parameters
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# to `PKCS7.verify`
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# See https://www.openssl.org/docs/manmaster/man3/PKCS7_verify.html
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signed_smime if signed_smime.verify(nil, store)
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end
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end
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end
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end
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end
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