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[Bug libc/11082] New: fclose(f); ftell(f); results in accesses on free'd memory
- From: "jur dot pauw at gmail dot com" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sources dot redhat dot com
- Date: 11 Dec 2009 10:21:56 -0000
- Subject: [Bug libc/11082] New: fclose(f); ftell(f); results in accesses on free'd memory
- Reply-to: sourceware-bugzilla at sourceware dot org
I used valgrind to find the origin of a crash. It shows that an ftell on a
closed file performs reads and writes on memory free'd by fclose. The
following small program (bug.c) reproduces the problem.
#include <stdio.h>
int main(int argc, char **argv)
{
FILE *f = fopen("bug.c", "r");
fclose(f);
ftell(f);
}
compiler/kernel/libc versions:
gcc version 3.4.4
Linux c3svr30 2.6.9-89.0.16.ELsmp #1 SMP Tue Oct 27 03:51:52 EDT 2009 x86_64
x86_64 x86_64 GNU/Linux
/lib/tls/libc-2.3.4.so
GNU C Library stable release version 2.3.4, by Roland McGrath et al.
Copyright (C) 2005 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 3.4.6 20060404 (Red Hat 3.4.6-8).
Compiled on a Linux 2.4.20 system on 2007-09-12.
Available extensions:
GNU libio by Per Bothner
crypt add-on version 2.1 by Michael Glad and others
Native POSIX Threads Library by Ulrich Drepper et al
RT using linux kernel aio
The C stubs add-on version 2.1.2.
BIND-8.2.3-T5B
NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
Glibc-2.0 compatibility add-on by Cristian Gafton
GNU Libidn by Simon Josefsson
Thread-local storage support included.
--
Summary: fclose(f); ftell(f); results in accesses on free'd
memory
Product: glibc
Version: 2.3.4
Status: NEW
Severity: normal
Priority: P2
Component: libc
AssignedTo: drepper at redhat dot com
ReportedBy: jur dot pauw at gmail dot com
CC: glibc-bugs at sources dot redhat dot com
http://sourceware.org/bugzilla/show_bug.cgi?id=11082
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