Read error: #<TypeError: can't modify frozen string> raised from HttpParser

Augusto Becciu augusto at jadedpixel.com
Mon Jun 7 23:01:50 EDT 2010


That looks perfect. Thanks Eric!

On Mon, Jun 7, 2010 at 11:45 PM, Eric Wong <normalperson at yhbt.net> wrote:
> Augusto Becciu <augusto at jadedpixel.com> wrote:
>> Hi Eric,
>>
>> Thanks for the ideas.
>>
>> Ended up adding some debugging code to unicorn that lead me to the
>> culprit of the problem. It turned out being a bug in the HttpParser.
>
> Thank you Augusto,
>
> Your explanation was good so I'll just use it as a commit message
> and credit you as the author.  See the patch below and let me know
> if everything looks alright before I push it out.
>
> I have a few small things to go over, but I'll be releasing 0.999.0
> tonight (which I hope will be the last before we finally celebrate
> have a 1.0.0 release).
>
> From 7d2295fa774d1c98dfbde2b09d93d58712253d24 Mon Sep 17 00:00:00 2001
> From: Augusto Becciu <augusto at jadedpixel.com>
> Date: Mon, 7 Jun 2010 23:02:43 -0300
> Subject: [PATCH] http: ignore Version: header if explicitly set by client
>
> When Unicorn receives a request with a "Version" header, the
> HttpParser transforms it into "HTTP_VERSION". After that tries to add
> it to the request hash which already contains a "HTTP_VERSION" key
> with the actual http version of the request. So it tries to append the
> new value separated by a comma. But since the http version is a
> freezed constant, the TypeError exception is raised.
>
> According to the HTTP RFC
> (http://www.w3.org/Protocols/rfc2616/rfc2616-sec7.html#sec7.1) a
> "Version" header is valid. However, it's not supported in rack, since
> rack has a HTTP_VERSION env variable for the http version. So I think
> the easiest way to deal with this problem is to just ignore the header
> since it is extremely unusual. We were getting it from a crappy bot.
>
> ref: http://mid.gmane.org/AANLkTimuGgcwNAMcVZdViFWdF-UcW_RGyZAue7phUXps@mail.gmail.com
>
> Acked-by: Eric Wong <normalperson at yhbt.net>
> ---
>  ext/unicorn_http/unicorn_http.rl |    9 +++++++++
>  test/unit/test_http_parser_ng.rb |   20 ++++++++++++++++++++
>  2 files changed, 29 insertions(+), 0 deletions(-)
>
> diff --git a/ext/unicorn_http/unicorn_http.rl b/ext/unicorn_http/unicorn_http.rl
> index 264db68..aa23024 100644
> --- a/ext/unicorn_http/unicorn_http.rl
> +++ b/ext/unicorn_http/unicorn_http.rl
> @@ -197,6 +197,15 @@ static void write_value(VALUE req, struct http_parser *hp,
>     assert_frozen(f);
>   }
>
> +  /*
> +   * ignore "Version" headers since they conflict with the HTTP_VERSION
> +   * rack env variable.
> +   */
> +  if (rb_str_cmp(f, g_http_version) == 0) {
> +    hp->cont = Qnil;
> +    return;
> +  }
> +
>   e = rb_hash_aref(req, f);
>   if (NIL_P(e)) {
>     hp->cont = rb_hash_aset(req, f, v);
> diff --git a/test/unit/test_http_parser_ng.rb b/test/unit/test_http_parser_ng.rb
> index a067ac8..cb30f32 100644
> --- a/test/unit/test_http_parser_ng.rb
> +++ b/test/unit/test_http_parser_ng.rb
> @@ -440,4 +440,24 @@ class HttpParserNgTest < Test::Unit::TestCase
>     end
>   end
>
> +  def test_ignore_version_header
> +    http = "GET / HTTP/1.1\r\nVersion: hello\r\n\r\n"
> +    req = {}
> +    assert_equal req, @parser.headers(req, http)
> +    assert_equal '', http
> +    expect = {
> +      "SERVER_NAME" => "localhost",
> +      "rack.url_scheme" => "http",
> +      "REQUEST_PATH" => "/",
> +      "SERVER_PROTOCOL" => "HTTP/1.1",
> +      "PATH_INFO" => "/",
> +      "HTTP_VERSION" => "HTTP/1.1",
> +      "REQUEST_URI" => "/",
> +      "SERVER_PORT" => "80",
> +      "REQUEST_METHOD" => "GET",
> +      "QUERY_STRING" => ""
> +    }
> +    assert_equal expect, req
> +  end
> +
>  end
> --
> Eric Wong
>


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