Reproducible oops in 2.4.10, khttpd crashing when apache is not running ; corresponding HTTP error message

Howdy,

First I would like to say hello to everyone in this list.

I'm running kernel 2.4.10 (Intel), and performing experiments with the khttpd server compiled as a module. I am writing to this list concerning a couple of things I noticed in khttpd, and offering a fix. I already sent this e-mail to the list, but not with a standard subject.

Problem description:
-----------------------------

I began noticing that it crashed with a oops or hanging the machine when apache was not running. When the machine survived, it also returned a 403 error, with a "Permission denied" message.

The hack:
------------------

Upon source investigation, I noticed that at /usr/src/linux/net/khttpd/userspace.c, at the function Userspace, in the place where's the user-daemon no present case is coded, a structure element is not released.

After correction, I have also changed the 403 error (permission denied), to a 503 Service Unavailable, as I believe it's more correct. If the khttpd daemon can't call Apache (or other userspace daemon) when it's not capable of processing the request, it's better to give a 503 message than a 403, for my and the users' sanity sake.

So, in the 2.4.10 kernel source tree, in the already mentioned /usr/src/linux/net/khttpd/userspace.c, at line 114, you can make the following changes:

Send403(CurrentRequest->sock); to Send50x(CurrentRequest-sock);

Append the following lines after the Send50x:
sock_release(CurrentRequest->sock);
CurrentRequest->sock=NULL;

This patch has already been tested by another two persorns.

A diff file is included as an attachment.

Regards,
--
Rui Ribeiro
Network and Security consultant
http://www.case.pt

P.S. A copy of this message has already been sent to khttpd users list.

101d100
<
102a102

113,119c113,115
<
< /* Rui */
< Send50x(CurrentRequest->sock); /* Sorry, no go... */
< sock_release(CurrentRequest->sock);
< CurrentRequest->sock = NULL; /* We no longer own it */
< /* End Rui */
<
---