general/7397: Apache dies in accept_mutex_on if httpd is setuid root

[Theron Tock <th...@best.com>]

>Number:         7397
>Category:       general
>Synopsis:       Apache dies in accept_mutex_on if httpd is setuid root
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    apache
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   apache
>Arrival-Date:   Mon Mar 12 18:50:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     theron@best.com
>Release:        1.3.19
>Organization:
apache
>Environment:
Redhat 6.1 -- but applies to all unix versions
>Description:
If httpd is made setuid root (which makes things easier to test) with
apache 1.3.19 it fails to start with the message:
  accept_mutex_on: permission denied
showing up over and over in the logs.

The problem is at line 766 of http_main.c:
  if (!getuid()) {
    .. set ownership on semaphore to ap_user_id
  }

Since httpd is running with euid == 0 and uid != 0
the block of code which sets the ownership on the
semaphore is skipped.  The if code should be checking
for geteuid() != 0, or perhaps even better it should
be checking for getuid() != ap_user_id.

This problem only cropped up in 1.3.19 since semaphores
are now the default on linux 2.2.x, whereas in early
versions of apache that used fcntl there was no issue.

-Theron, 12 Mar 2001
>How-To-Repeat:
1) Build apache
2) chown root ${install-dir}/bin/httpd
3) chmod u+s ${install-dir}/bin/httpd
4) ${install-dir}/bin/apachectl start
>Fix:
Yes, see full description.
>Release-Note:
>Audit-Trail:
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