Date: Sun, 12 Sep 2004 20:11:07 GMT From: Giorgos Keramidas <keramida@freebsd.org> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/71651: [PATCH] cron may attept to close unopened file Message-ID: <200409122011.i8CKB7aI028235@freefall.freebsd.org>
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The following reply was made to PR bin/71651; it has been noted by GNATS.
From: Giorgos Keramidas <keramida@freebsd.org>
To: Dan Lukes <dan@obluda.cz>
Cc: bug-followup@freebsd.org
Subject: Re: bin/71651: [PATCH] cron may attept to close unopened file
Date: Sun, 12 Sep 2004 23:01:55 +0300
On 2004-09-12 16:15, Dan Lukes <dan@obluda.cz> wrote:
>
> >Number: 71651
> >Category: bin
> >Synopsis: [PATCH] cron may attept to close unopened file
> >Confidential: no
> >Severity: serious
> >Priority: low
> >Responsible: freebsd-bugs
> >State: open
> >Quarter:
> >Keywords:
> >Date-Required:
> >Class: sw-bug
> >Submitter-Id: current-users
> >Arrival-Date: Sun Sep 12 14:20:22 GMT 2004
> >Closed-Date:
> >Last-Modified:
> >Originator: Dan Lukes
> >Release: FreeBSD 5.3-BETA3 i386
> >Organization:
> Obludarium
> >Environment:
> System: FreeBSD kulesh.obluda.cz 5.3-BETA3 FreeBSD 5.3-BETA3 #8: Sun Sep 5 07:06:40 CEST 2004 dan@kulesh.obluda.cz:/usr/obj/usr/src/sys/Dan i386
> usr.sbin/cron/lib/misc.c,v 1.11 2002/08/04 04:32:27 tjr
> usr.sbin/cron/cron/cron.c,v 1.15 2004/05/16 19:29:33 yar
> usr.sbin/cron/cron/do_command.c,v 1.22 2004/05/16 19:29:33 yar
>
> >Description:
> usr.sbin/cron/lib/misc.c:413: warning: 'deny' might be used uninitialized in this function
>
> It's sign of true bug. When fopen of ALLOW_FILE fail for other than ENOENT
> reason, then "goto out" apply then 'if (deny)' is evaluated and
> 'fclose(deny)' may be called athought 'deny' is uninitialized variable.
The check to avoid calling fclose() with NULL is already there. You
just have to make sure that `allow' and `deny' are always initialized to
NULL to let it work as expected :-)
%%%
Index: misc.c
===================================================================
RCS file: /home/ncvs/src/usr.sbin/cron/lib/misc.c,v
retrieving revision 1.11
diff -u -r1.11 misc.c
--- misc.c 4 Aug 2002 04:32:27 -0000 1.11
+++ misc.c 12 Sep 2004 19:55:31 -0000
@@ -410,7 +410,8 @@
allowed(username)
char *username;
{
- FILE *allow, *deny;
+ FILE *allow = NULL;
+ FILE *deny = NULL;
int isallowed;
isallowed = FALSE;
@@ -421,9 +422,6 @@
if ((deny = fopen(DENY_FILE, "r")) == NULL && errno != ENOENT)
goto out;
Debug(DMISC, ("allow/deny enabled, %d/%d\n", !!allow, !!deny))
-#else
- allow = NULL;
- deny = NULL;
#endif
if (allow)
%%%
> struct tm otztm; /* time in the old time zone */
> - int otzminute, otzhour, otzdom, otzmonth, otzdow;
> + int otzminute = otzminute, /* "init" to avoid "might be used uninitialized" warning */
> + otzhour = otzhour, otzdom = otzdom,
> + otzmonth = otzmonth, otzdow = otzmonth;
Please don't use this. There's probably a true bug hidden here.
Hiding it is not good.
> if (ch != EOF) {
> - register FILE *mail;
> + register FILE *mail = mail; /* "init" to avoid "might be used uninitialized" warning */
Use NULL as the initialization of (FILE *) objects. If they are indeed
used before a proper initialization is done this will expose the true
bugs and let us fix them ;-)
- Giorgos
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