Date: Wed, 13 Dec 2000 05:19:51 -0800 (PST) From: luddes@hotmail.com To: freebsd-gnats-submit@FreeBSD.org Subject: misc/23521: NULL pointer write in vfprintf code Message-ID: <200012131319.eBDDJps70162@freefall.freebsd.org> Resent-Message-ID: <200012131320.eBDDK1670193@freefall.freebsd.org>
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>Number: 23521
>Category: misc
>Synopsis: NULL pointer write in vfprintf code
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Wed Dec 13 05:20:01 PST 2000
>Closed-Date:
>Last-Modified:
>Originator: Ludde
>Release: 4.1.1
>Organization:
>Environment:
FreeBSD matchbox.dumle.nu 4.1.1-RELEASE FreeBSD 4.1.1-RELEASE #3: Wed Dec 6 19:34:33 CET 2000 root@matchbox.dumle.nu:/usr/src/sys/compile/MATCHBOX i386
>Description:
This code crashes because of a NULL pointer write inside the vfprintf code.
It should print the 8th argument as an integer.
printf("%8$d", 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
GDB output:
0x280d49e0 in vfprintf () from /usr/lib/libc.so.4
(gdb) x/i $eip
0x280d49e0 <vfprintf+10028>: mov %eax,(%edx)
(gdb) info reg edx
edx 0x0 0
>How-To-Repeat:
Compile a C program with this contents:
int main() {
printf("%8$d", 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
}
and run it
>Fix:
Perhaps the memory allocation failure is at:
if (tablemax >= STATIC_ARG_TBL_SIZE) {
*argtable = (void **)
malloc (sizeof (void *) * (tablemax + 1));
}
>Release-Note:
>Audit-Trail:
>Unformatted:
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