[ruby-core:81262] [Ruby trunk Bug#13429] Net::SMTP has no read timeout when connexion over TLS

Issue #13429 has been updated by shugo (Shugo Maeda).

Assignee set to usa (Usaku NAKAMURA)

keysen (J辿r辿my Carlier) wrote:
> When connecting using TLS to an unresponsive SMTP server, Net::SMTP can hang until 10 minutes.

In Ruby 2.4, open_timeout affects TLS handshake.
I'm not sure whether it should be backported to 2.3.

What do you think, usa-san?


----------------------------------------
Bug #13429: Net::SMTP has no read timeout when connexion over TLS
https://bugs.ruby-lang.org/issues/13429#change-64929

* Author: keysen (J辿r辿my Carlier)
* Status: Open
* Priority: Normal
* Assignee: usa (Usaku NAKAMURA)
* Target version: 
* ruby -v: 2.3.1
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
Hello,


When connecting using TLS to an unresponsive SMTP server, Net::SMTP can hang until 10 minutes.

The issue is here, we should have a read timeout:

``` ruby
    def tlsconnect(s)
      verified = false
      s = ssl_socket(s, @ssl_context)
      logging "TLS connection started"
      s.sync_close = true
      s.connect
      if @ssl_context.verify_mode != OpenSSL::SSL::VERIFY_NONE
        s.post_connection_check(@address)
      end
      verified = true
      s
    ensure
      s.close unless verified
    end
```

To workaround the issue for the moment I used:

``` ruby
module Net
  class SMTP
    alias :original_tlsconnect :tlsconnect

    def tlsconnect(s)
      Timeout.timeout(@read_timeout, Net::ReadTimeout) { original_tlsconnect(s) }
    end
  end
end
```

Here the steps to reproduce the bug:

``` ruby
smtp = Net::SMTP.new('mail.example.com', 465)
smtp.read_timeout = 3
smtp.enable_tls
smtp.start('localhost.localdomain', '[e-mail]', '********') {}
```

Sorry for the credentials I can't provide this publicly, after testing with one failing server you will be able to see that the read timeout is ignored.
By failing server I mean an SMTPS server where you are able to open a connection but you can't read on the socket.

Working case:

``` ruby
smtp = Net::SMTP.new('mail.example.com', 465)
smtp.read_timeout = 3
smtp.start('localhost.localdomain', '[e-mail]', '********') {}
```

Without TLS it's ok!

If you have any questions, suggestions just ask, if I can help.



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