Valid ips v4 and v6. Right logic for working with X-FORWARDED-FOR header and tests.

1 files changed, 68 insertions, 22 deletions

diff --git a/actionpack/lib/action_dispatch/middleware/remote_ip.rb b/actionpack/lib/action_dispatch/middleware/remote_ip.rb
index d924f21fad..ec15a2a715 100644
--- a/actionpack/lib/action_dispatch/middleware/remote_ip.rb
+++ b/actionpack/lib/action_dispatch/middleware/remote_ip.rb
@@ -5,11 +5,14 @@ module ActionDispatch
     # IP addresses that are "trusted proxies" that can be stripped from
     # the comma-delimited list in the X-Forwarded-For header. See also:
     # http://en.wikipedia.org/wiki/Private_network#Private_IPv4_address_spaces
+    # http://en.wikipedia.org/wiki/Private_network#Private_IPv6_addresses.
     TRUSTED_PROXIES = %r{
       ^127\.0\.0\.1$                | # localhost
+      ^::1$                         |
       ^(10                          | # private IP 10.x.x.x
         172\.(1[6-9]|2[0-9]|3[0-1]) | # private IP in the range 172.16.0.0 .. 172.31.255.255
-        192\.168                      # private IP 192.168.x.x
+        192\.168                    | # private IP 192.168.x.x
+        fc00::                        # private IP fc00
        )\.
     }x
 
@@ -19,13 +22,13 @@ module ActionDispatch
       @app = app
       @check_ip = check_ip_spoofing
       @proxies = case custom_proxies
-      when Regexp
-        custom_proxies
-      when nil
-        TRUSTED_PROXIES
-      else
-        Regexp.union(TRUSTED_PROXIES, custom_proxies)
-      end
+        when Regexp
+          custom_proxies
+        when nil
+          TRUSTED_PROXIES
+        else
+          Regexp.union(TRUSTED_PROXIES, custom_proxies)
+        end
     end
 
     def call(env)
@@ -34,6 +37,31 @@ module ActionDispatch
     end
 
     class GetIp
+
+      # IP v4 and v6 (with compression) validation regexp
+      # https://gist.github.com/1289635
+      VALID_IP = %r{
+        (^(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[0-9]{1,2})(\.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[0-9]{1,2})){3}$)                                                        | # ip v4
+        (^(
+        (([0-9A-Fa-f]{1,4}:){7}[0-9A-Fa-f]{1,4})                                                                                                                   | # ip v6 not abbreviated
+        (([0-9A-Fa-f]{1,4}:){6}:[0-9A-Fa-f]{1,4})                                                                                                                  | # ip v6 with double colon in the end
+        (([0-9A-Fa-f]{1,4}:){5}:([0-9A-Fa-f]{1,4}:)?[0-9A-Fa-f]{1,4})                                                                                              | # - ip addresses v6
+        (([0-9A-Fa-f]{1,4}:){4}:([0-9A-Fa-f]{1,4}:){0,2}[0-9A-Fa-f]{1,4})                                                                                          | # - with
+        (([0-9A-Fa-f]{1,4}:){3}:([0-9A-Fa-f]{1,4}:){0,3}[0-9A-Fa-f]{1,4})                                                                                          | # - double colon
+        (([0-9A-Fa-f]{1,4}:){2}:([0-9A-Fa-f]{1,4}:){0,4}[0-9A-Fa-f]{1,4})                                                                                          | # - in the middle
+        (([0-9A-Fa-f]{1,4}:){6} ((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3} (\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))                            | # ip v6 with compatible to v4
+        (([0-9A-Fa-f]{1,4}:){1,5}:((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))                           | # ip v6 with compatible to v4
+        (([0-9A-Fa-f]{1,4}:){1}:([0-9A-Fa-f]{1,4}:){0,4}((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))     | # ip v6 with compatible to v4
+        (([0-9A-Fa-f]{1,4}:){0,2}:([0-9A-Fa-f]{1,4}:){0,3}((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))   | # ip v6 with compatible to v4
+        (([0-9A-Fa-f]{1,4}:){0,3}:([0-9A-Fa-f]{1,4}:){0,2}((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))   | # ip v6 with compatible to v4
+        (([0-9A-Fa-f]{1,4}:){0,4}:([0-9A-Fa-f]{1,4}:){1}((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))     | # ip v6 with compatible to v4
+        (::([0-9A-Fa-f]{1,4}:){0,5}((\b((25[0-5])|(1\d{2})|(2[0-4]\d) |(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))                         | # ip v6 with compatible to v4
+        ([0-9A-Fa-f]{1,4}::([0-9A-Fa-f]{1,4}:){0,5}[0-9A-Fa-f]{1,4})                                                                                               | # ip v6 with compatible to v4
+        (::([0-9A-Fa-f]{1,4}:){0,6}[0-9A-Fa-f]{1,4})                                                                                                               | # ip v6 with double colon at the begining
+        (([0-9A-Fa-f]{1,4}:){1,7}:)                                                                                                                                  # ip v6 without ending
+        )$)
+      }x
+
       def initialize(env, middleware)
         @env           = env
         @middleware    = middleware
@@ -44,25 +72,31 @@ module ActionDispatch
       # but will be wrong if the user is behind a proxy. Proxies will set
       # HTTP_CLIENT_IP and/or HTTP_X_FORWARDED_FOR, so we prioritize those.
       # HTTP_X_FORWARDED_FOR may be a comma-delimited list in the case of
-      # multiple chained proxies. The last address which is not a known proxy
-      # will be the originating IP.
+      # multiple chained proxies. The first address which is in this list
+      # if it's not a known proxy will be the originating IP.
+      # Format of HTTP_X_FORWARDED_FOR:
+      # client_ip, proxy_ip1, proxy_ip2...
+      # http://en.wikipedia.org/wiki/X-Forwarded-For
       def calculate_ip
-        client_ip     = @env['HTTP_CLIENT_IP']
-        forwarded_ips = ips_from('HTTP_X_FORWARDED_FOR')
-        remote_addrs  = ips_from('REMOTE_ADDR')
+        client_ip    = @env['HTTP_CLIENT_IP']
+        forwarded_ip = ips_from('HTTP_X_FORWARDED_FOR').first
+        remote_addrs = ips_from('REMOTE_ADDR')
 
         check_ip = client_ip && @middleware.check_ip
-        if check_ip && !forwarded_ips.include?(client_ip)
+        if check_ip && forwarded_ip != client_ip
           # We don't know which came from the proxy, and which from the user
           raise IpSpoofAttackError, "IP spoofing attack?!" \
             "HTTP_CLIENT_IP=#{@env['HTTP_CLIENT_IP'].inspect}" \
             "HTTP_X_FORWARDED_FOR=#{@env['HTTP_X_FORWARDED_FOR'].inspect}"
         end
 
-        not_proxy = client_ip || forwarded_ips.first || remote_addrs.first
-
-        # Return first REMOTE_ADDR if there are no other options
-        not_proxy || ips_from('REMOTE_ADDR', :allow_proxies).first
+        client_ips = remove_proxies [client_ip, forwarded_ip, remote_addrs].flatten
+        if client_ips.present?
+          client_ips.first
+        else
+          # If there is no client ip we can return first valid proxy ip from REMOTE_ADDR
+          remote_addrs.find { |ip| valid_ip? ip }
+        end
       end
 
       def to_s
@@ -71,12 +105,24 @@ module ActionDispatch
         @ip = calculate_ip
       end
 
-    protected
+      private
 
-      def ips_from(header, allow_proxies = false)
-        ips = @env[header] ? @env[header].strip.split(/[,\s]+/) : []
-        allow_proxies ? ips : ips.reject{|ip| ip =~ @middleware.proxies }
+      def ips_from(header)
+        @env[header] ? @env[header].strip.split(/[,\s]+/) : []
       end
+
+      def valid_ip?(ip)
+        ip =~ VALID_IP
+      end
+
+      def not_a_proxy?(ip)
+        ip !~ @middleware.proxies
+      end
+
+      def remove_proxies(ips)
+        ips.select { |ip| valid_ip?(ip) && not_a_proxy?(ip) }
+      end
+
     end
 
   end