Bugs

= Nginx Bugs =

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This is a poor man's bug tracker, until something better comes along.

A segmentation fault occurs when using the fastcgi_catch_stderr directive.
Reported by Manlio Perillo.

[PATCH] mail bugs
From: Mansoor Peerbhoy  Subject: (resending) bug in ngx_mail_proxy_read_response Newsgroups: gmane.comp.web.nginx.english Date: 2007-11-11 11:22:36 GMT

Hello Igor, please ignore my earlier e-mail since it was incomplete:

We have come across a small bug in the function ngx_mail_proxy_read_response in src/mail/ngx_mail_proxy_module.c: Basically, after sending the LOGIN command (along with the password) to the upstream server, NGINX immediately expects the tagged response (OK/NO) from the upstream server.

However, according to the IMAP RFC 3501, section 6.2.3:


 * A server MAY include a CAPABILITY response code in the tagged OK
 * response to a successful LOGIN command in order to send
 * capabilities automatically. It is unnecessary for a client to
 * send a separate CAPABILITY command if it recognizes these
 * automatic capabilities.

This breaks nginx because it is searching for the tagged response in the switch case inside the ngx_mail_proxy_read_response function (case ngx_imap_passwd).

This causes the following error to appear in nginx logs, because the code is not able to handle the untagged response:

2007/11/11 16:03:40 [info] 3917#0: *3 upstream sent invalid response: "* CAPABILITY IMAP4rev1 ACL BINARY CATENATE CHILDREN CONDSTORE ESEARCH ID IDLE LIST-EXTENDED LITERAL+ LOGIN-REFERRALS MULTIAPPEND NAMESPACE QUOTA RIGHTS=ektx SASL-IR UIDPLUS UNSELECT WITHIN X-DRAFT-I05-SEARCHRES 1 OK LOGIN completed" while reading response from upstream, client: 127.0.0.1, server: 0.0.0.0:1143, login: "user1@...", upstream: 127.0.0.1:7143

There is also another issue. During integration of nginx proxy with our Zimbra IMAP mail server, we have noticed the following: If the server side does a flush between sending the untagged capability response and the tagged result to the LOGIN command, as follows:

1 login mansoor secret LOGIN-REFERRALS MULTIAPPEND NAMESPACE QUOTA RIGHTS=ektx SASL-IR UIDPLUS UNSELECT WITHIN X-DRAFT-I05-SEARCHRES // - upstream server flushes socket - 1 OK LOGIN completed
 * OK localhost Zimbra IMAP4rev1 service ready
 * CAPABILITY IMAP4rev1 ACL BINARY CATENATE CHILDREN CONDSTORE ESEARCH ID IDLE LIST-EXTENDED LITERAL+

In this case, the recv function call at the start of the ngx_mail_proxy_read_response function does not receive both the lines in one call (we require to make a second call to recv to fetch the tagged response).

The attached patch fixes both issues, I have commented the code as necessary.

Please consider including the patch into nginx (I tested the bug, and the patch on nginx-0.5.33).

Regards,

Md. Mansoor Peerbhoy http://www.zimbra.com/

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