Add cgi_mode to parse_header to support LF in CGI headers

lib/webrick/httpservlet/cgihandler.rb

@@ -96,7 +96,7 @@ def do_GET(req, res)
           "Premature end of script headers: #{@script_filename}" if body.nil?
 
         begin
-          header = HTTPUtils::parse_header(raw_header)
+          header = HTTPUtils::parse_header(raw_header, true)
           if /^(\d+)/ =~ header['status'][0]
             res.status = $1.to_i
             header.delete('status')

lib/webrick/httputils.rb

@@ -168,17 +168,22 @@ def join(separator = "; ")
       "cookie" => CookieHeader,
     })
 
-    def parse_header(raw)
+    def parse_header(raw, cgi_mode = false)
       header = Hash.new([].freeze)
       field = nil
+
+      line_break = cgi_mode ? "\\r?\\n" : "\\r\\n"
+      header_line = Regexp.new(/^([A-Za-z0-9!\#$%&'*+\-.^_`|~]+):([^\r\n\0]*?)#{line_break}\z/m)
+      continued_header_lines = Regexp.new(/^[ \t]+([^\r\n\0]*?)#{line_break}/m)
+
       raw.each_line{|line|
         case line
-        when /^([A-Za-z0-9!\#$%&'*+\-.^_`|~]+):([^\r\n\0]*?)\r\n\z/om
+        when header_line
           field, value = $1, $2
           field.downcase!
           header[field] = HEADER_CLASSES[field].new unless header.has_key?(field)
           header[field] << value
-        when /^[ \t]+([^\r\n\0]*?)\r\n/om
+        when continued_header_lines
           unless field
             raise HTTPStatus::BadRequest, "bad header '#{line}'."
           end

sig/httputils.rbs

@@ -26,7 +26,7 @@ module WEBrick
 
     HEADER_CLASSES: Hash[String, untyped]
 
-    def self?.parse_header: (String raw) -> Hash[String, Array[String]]
+    def self?.parse_header: (String raw, ?bool cgi_mode) -> Hash[String, Array[String]]
 
     def self?.split_header_value: (String str) -> Array[String]
 

test/webrick/test_cgi.rb

@@ -145,4 +145,15 @@ def test_bad_header
       assert_not_match(CtrlPat, s)
     }
   end
+
+  def test_bare_lf_in_cgi_header
+    TestWEBrick.start_cgi_server do |server, addr, port, log|
+      http = Net::HTTP.new(addr, port)
+      req = Net::HTTP::Get.new("/webrick_bare_lf.cgi")
+      assert_nothing_raised do
+        res = http.request(req)
+        assert_equal res['Content-Type'], 'text/plain'
+      end
+    end
+  end
 end

test/webrick/webrick_bare_lf.cgi

@@ -0,0 +1,8 @@
+#!ruby
+
+body = "test for bare LF in cgi header"
+
+print "Content-Type: text/plain\n"
+print "Content-Length: #{body.size}\n"
+print "\n"
+print body