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1 files changed, 101 insertions, 0 deletions

diff --git a/lib/mixlib/authentication/signatureverification.rb b/lib/mixlib/authentication/signatureverification.rb
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+++ b/lib/mixlib/authentication/signatureverification.rb
@@ -0,0 +1,101 @@
+require 'ostruct'
+require 'net/http'
+
+require 'mixlib/authentication/signedheaderauth'
+require 'mixlib/authentication/digester'
+
+module Mixlib
+  module Authentication
+    class SignatureVerification
+
+      include Mixlib::Authentication::SignedHeaderAuth
+      
+      attr_reader :hashed_body, :timestamp, :http_method, :user_id
+
+      # Takes the request, boils down the pieces we are interested in,
+      # looks up the user, generates a signature, and compares to
+      # the signature in the request
+      # ====Headers
+      #
+      # X-Ops-Sign: algorithm=sha256;version=1.0;
+      # X-Ops-UserId: <user_id>
+      # X-Ops-Timestamp:
+      # X-Ops-Content-Hash: 
+      def authenticate_user_request(request, user_lookup, time_skew=(15*60))
+        Mixlib::Authentication::Log.debug "Initializing header auth : #{request.inspect}"
+        
+        headers ||= request.env.inject({ }) { |memo, kv| memo[$2.downcase.to_sym] = kv[1] if kv[0] =~ /^(HTTP_)(.*)/; memo }
+        digester = Mixlib::Authentication::Digester.new        
+
+        begin
+          @allowed_time_skew   = time_skew # in seconds
+          @http_method         = request.method.to_s
+          @signing_description = headers[:x_ops_sign].chomp
+          @user_id             = headers[:x_ops_userid].chomp
+          @timestamp           = headers[:x_ops_timestamp].chomp
+          @request_signature   = headers[:authorization].chomp.gsub!(/\n\t/,"\n")
+          @host                = headers[:host].chomp
+          @content_hash        = headers[:x_ops_content_hash].chomp
+          @user_secret         = user_lookup
+
+
+          file_param = request.params["file"]
+
+          @hashed_body = if file_param
+                           Mixlib::Authentication::Log.debug "Digesting file_param: '#{file_param.inspect}'"
+                           if file_param.respond_to?(:has_key?)
+                             tempfile = file_param[:tempfile]
+                             digester.hash_file(tempfile)
+                           else
+                             digester.hash_body(file_param)
+                           end
+                         else
+                           body = request.raw_post
+                           Mixlib::Authentication::Log.debug "Digesting body: '#{body}'"
+                           digester.hash_body(body)
+                         end
+
+          Mixlib::Authentication::Log.debug "Authenticating user : #{user_id}, User secret is: #{@user_secret}, Request signature is :\n#{@request_signature}, Hashed Body is #{@hashed_body}"
+          
+          #BUGBUG Not doing anything with the signing description yet [cb]          
+          parse_signing_description
+          candidate_block = canonicalize_request
+          request_decrypted_block = @user_secret.public_decrypt(Base64.decode64(@request_signature))
+          signatures_match = (request_decrypted_block == candidate_block)
+          timeskew_is_acceptable = timestamp_within_bounds?(Time.parse(timestamp), Time.now)
+          hashes_match = @content_hash == hashed_body
+        rescue StandardError=>se
+          raise StandardError,"Failed to authenticate user request.  Most likely missing a necessary header: #{se.message}"
+        end
+        
+        Mixlib::Authentication::Log.debug "Candidate Block is: '#{candidate_block}'\nRequest decrypted block is: '#{request_decrypted_block}'\nCandidate content hash is: #{hashed_body}\nRequest Content Hash is: '#{@content_hash}'\nSignatures match: #{signatures_match}, Allowed Time Skew: #{timeskew_is_acceptable}, Hashes match?: #{hashes_match}\n"
+        
+        if signatures_match and timeskew_is_acceptable and hashes_match
+          OpenStruct.new(:name=>user_id)
+        else
+          nil
+        end
+      end
+      
+      private
+      
+      # Compare the request timestamp with boundary time
+      # 
+      # 
+      # ====Parameters
+      # time1<Time>:: minuend
+      # time2<Time>:: subtrahend
+      #
+      def timestamp_within_bounds?(time1, time2)
+        time_diff = (time2-time1).abs
+        is_allowed = (time_diff < @allowed_time_skew)
+        Mixlib::Authentication::Log.debug "Request time difference: #{time_diff}, within #{@allowed_time_skew} seconds? : #{!!is_allowed}"
+        is_allowed      
+      end
+    end
+
+
+  end
+end
+
+