Bug 496451

Created attachment 340224 [details]
A custom bash cgi script

Description of problem:
For two years now we're running printer servers on RHEL 5,5.1,5.2 x86_64 (and before that on Fedora) - atop cups 1.2.4.
We have a custom _bash_ cgi script (attached) that basically outputs something like:

    Location: /printers/
    Set-Cookie: RASHUT=SUPPORT; path=/
    
(ex. in response to /rashut.cgi?RASHUT=SUPPORT)
to set a cookie and redirect the client to the printers page.
This works fine on the above mentioned platforms.

We set up a test system running RHEL 5.3 - with cups 1.3.7 - and now this script fails in the following way:

    Every 2 out of 5 (40% of) request fails:
    1. The client (IE 7/Win XP) stalls for 300 seconds
    2. The log file - error_log - shows this:

D [18/Apr/2009:01:50:05 +0300] cupsdAcceptClient: skipping getpeercon()
D [18/Apr/2009:01:50:05 +0300] cupsdAcceptClient: 13 from 10.236.33.36:631 (IPv4)
D [18/Apr/2009:01:50:05 +0300] cupsdReadClient: 13 GET /rashut.cgi?RASHUT=YVN HTTP/1.1
D [18/Apr/2009:01:50:05 +0300] cupsdAuthorize: No authentication data provided.
D [18/Apr/2009:01:50:05 +0300] cupsdIsAuthorized: username=""
D [18/Apr/2009:01:50:05 +0300] cupsdSendError: 13 code=401 (Unauthorized)
D [18/Apr/2009:01:50:05 +0300] cupsdSendHeader: WWW-Authenticate: Basic realm="CUPS"
D [18/Apr/2009:01:50:05 +0300] cupsdCloseClient: 13
D [18/Apr/2009:01:50:05 +0300] cupsdAcceptClient: skipping getpeercon()
D [18/Apr/2009:01:50:05 +0300] cupsdAcceptClient: 13 from 10.236.33.36:631 (IPv4)
D [18/Apr/2009:01:50:05 +0300] cupsdReadClient: 13 GET /rashut.cgi?RASHUT=YVN HTTP/1.1
D [18/Apr/2009:01:50:05 +0300] cupsdAuthorize: Authorized as 022419873 using Basic
D [18/Apr/2009:01:50:05 +0300] cupsdIsAuthorized: username="022419873"
D [18/Apr/2009:01:50:05 +0300] [CGI] /usr/share/doc/cups-1.3.7/he/rashut.cgi started - PID = 31846
I [18/Apr/2009:01:50:05 +0300] Started "/usr/share/doc/cups-1.3.7/he/rashut.cgi" (pid=31846)
D [18/Apr/2009:01:50:05 +0300] cupsdSendCommand: 13 file=16
D [18/Apr/2009:01:50:06 +0300] PID 31846 (/usr/share/doc/cups-1.3.7/he/rashut.cgi) exited with no errors.
...[snip]...
D [18/Apr/2009:01:55:07 +0300] Closing client 13 after 300 seconds of inactivity...
D [18/Apr/2009:01:55:07 +0300] cupsdCloseClient: 13

    3. At that point the client (IE 7/Win XP) continues and shows this in its logs:
        HTTP/1.0 200 This buggy server did not return headers
        
        HTTP/1.1 303 See Other
        Date: Sat, 18 Apr 2009 00:46:08 GMT
        Server: CUPS/1.2
        Connection: Keep-Alive
        Keep-Alive: timeout=60
        Content-Language: he_IL
        Content-Length: 0
        Location: /printers/?QUERY=NAT
    4. Notice that the `Set-Cookie' header was not received nor the `blank' line after the last header.

I have found (after 3 hours of scratching and standing on my head) two workarounds. Detailed later under `Additional info'.


Version-Release number of selected component (if applicable):
RHEL 5.3, cups 1.3.7-8, bash 3.2-24, ksh 20080202-2, coreutils 5.97-19

How reproducible:
Very.

Steps to Reproduce:
1. Place rashut.cgi in /usr/share/cups/doc
2. Require authentication for the CUPS server. eg. in cupsd.conf
    Listen *:631
    <Location />
      AuthType Basic
      Require valid-user
      Satisfy any
      Order allow,deny
      Allow localhost
    </Location>
3. Configure cups to handle cgi scripts. In /etc/cups/cgi.types add:
      application/x-httpd-cgi cgi
4. Restart cups
5. From a client machine browse to: 
       http://server.domain:631/rashut.cgi?RASHUT=SUPPORT
  
Actual results:
In 2 out of 5 requests the browser stalls for 300 seconds.

Expected results:
Always be promptly redirected to /printers and get the cookie RASHUT.

Additional info:
As mentioned I have found (after 3 hours of scratching and standing on my head) two workarounds:
  1. make the rashut.cgi script a ksh script. eg. change 
       #!/bin/bash
     to
       #!/bin/ksh
or
  2. add `|cat' to the `echo' command in rashut.cgi. eg.:

     echo -e "Location: /printers/${RASHUT:+?QUERY=$RASHUT}
     Set-Cookie: RASHUT=${COOKIE:-$RASHUT}; path=/
     "|cat

then all request are answered correctly.