45 lines
1.3 KiB
Ruby
45 lines
1.3 KiB
Ruby
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module ActiveSupport
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# MessageVerifier makes it easy to generate and verify messages which are signed
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# to prevent tampering.
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#
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# This is useful for cases like remember-me tokens and auto-unsubscribe links where the
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# session store isn't suitable or available.
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#
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# Remember Me:
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# cookies[:remember_me] = @verifier.generate_message([@user.id, 2.weeks.from_now])
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#
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# In the authentication filter:
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#
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# id, time = @verifier.verify_message(cookies[:remember_me])
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# if time < Time.now
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# self.current_user = User.find(id)
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# end
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#
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class MessageVerifier
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class InvalidSignature < StandardError; end
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def initialize(secret, digest = 'SHA1')
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@secret = secret
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@digest = digest
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end
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def verify_message(signed_message)
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data, digest = signed_message.split("--")
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if digest != generate_digest(data)
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raise InvalidSignature
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else
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Marshal.load(ActiveSupport::Base64.decode64(data))
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end
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end
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def generate_message(value)
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data = ActiveSupport::Base64.encode64s(Marshal.dump(value))
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"#{data}--#{generate_digest(data)}"
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end
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private
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def generate_digest(data)
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OpenSSL::HMAC.hexdigest(OpenSSL::Digest::Digest.new(@digest), @secret, data)
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end
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end
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end
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