www-apache-bugdb mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Andrew Kuchling <akuch...@cnri.reston.va.us>
Subject mod_jserv/4104: Typos (& and &&) in mod_jserv.c
Date Tue, 23 Mar 1999 17:46:34 GMT

>Number:         4104
>Category:       mod_jserv
>Synopsis:       Typos (& and &&) in mod_jserv.c
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    jserv
>State:          open
>Class:          sw-bug
>Submitter-Id:   apache
>Arrival-Date:   Tue Mar 23 09:50:00 PST 1999
>Last-Modified:
>Originator:     akuchlin@cnri.reston.va.us
>Organization:
apache
>Release:        1.3.3 + 1.0b3
>Environment:
Solaris 2.6
>Description:
When trying to debug an Apache problem with Electric Fence, EF reported
an out-of-bounds access.  This turned out to stem from this code in mod_jserv.c:

        /* Try to find if we have a protocol://host */
        for (x=0; (x<128) & (buf[x]!='\0'); x++) {
            if ((buf[x]==':') & (buf[x+1]=='/') & (buf[x+2]=='/')) {
            ^^^^ previous line is caught by ElectricFence
                if (x!=0) {
                    protocol=buf;
                    buf[x]='\0';
                }

The bug is a typo, or confusion on the part of the person who wrote the code;
the bitwise operator & was used instead of the logical operator &&.
& isn't short-circuited and && is, so the above line always accesses
all of  buf[x], buf[x+1], buf[x+2].
>How-To-Repeat:
Compile Apache with Electric Fence, and edit main/alloc.c to use malloc()
and free().
>Fix:
A patch that fixes the place where EF segfaults is at
   ftp://starship.python.net/pub/crew/amk/new/jserv-patch

This patch does NOT fix all the typos.  Do a search for '{space}&{space}'
and '{space}|{space}', and you'll find other places where bitwise operators
have been used where logical ones make more sense.  

A grep through the other C files didn't turn up any problems, so mod_jserv.c
may be the only affected file.
>Audit-Trail:
>Unformatted:
[In order for any reply to be added to the PR database, ]
[you need to include <apbugs@Apache.Org> in the Cc line ]
[and leave the subject line UNCHANGED.  This is not done]
[automatically because of the potential for mail loops. ]
[If you do not include this Cc, your reply may be ig-   ]
[nored unless you are responding to an explicit request ]
[from a developer.                                      ]
[Reply only with text; DO NOT SEND ATTACHMENTS!         ]




Mime
View raw message