From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <sourceware-bugzilla@sourceware.org>
Received: by sourceware.org (Postfix, from userid 48)
 id 002D33857007; Tue,  7 Jul 2020 22:53:48 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 002D33857007
From: "jsm28 at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug stdio/26214] New: printf_fp double free
Date: Tue, 07 Jul 2020 22:53:48 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: glibc
X-Bugzilla-Component: stdio
X-Bugzilla-Version: 2.32
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: jsm28 at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: unassigned at sourceware dot org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
Message-ID: <bug-26214-131@http.sourceware.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://sourceware.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: glibc-bugs@sourceware.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Glibc-bugs mailing list <glibc-bugs.sourceware.org>
List-Unsubscribe: <http://sourceware.org/mailman/options/glibc-bugs>,
 <mailto:glibc-bugs-request@sourceware.org?subject=unsubscribe>
List-Archive: <https://sourceware.org/pipermail/glibc-bugs/>
List-Help: <mailto:glibc-bugs-request@sourceware.org?subject=help>
List-Subscribe: <http://sourceware.org/mailman/listinfo/glibc-bugs>,
 <mailto:glibc-bugs-request@sourceware.org?subject=subscribe>
X-List-Received-Date: Tue, 07 Jul 2020 22:53:49 -0000

https://sourceware.org/bugzilla/show_bug.cgi?id=3D26214

            Bug ID: 26214
           Summary: printf_fp double free
           Product: glibc
           Version: 2.32
            Status: NEW
          Severity: normal
          Priority: P2
         Component: stdio
          Assignee: unassigned at sourceware dot org
          Reporter: jsm28 at gcc dot gnu.org
  Target Milestone: ---

__printf_fp_l has a double free bug in the case where it allocates memory w=
ith
malloc internally, then has an I/O error while outputting trailing padding =
and
tries to free that already-freed memory when the error occurs. The following
test reproduces that bug (with a segfault).

#include <stdio.h>
#include <stdlib.h>

int
main (void)
{
  FILE *fp;
  char buf[131072];
  if ((fp =3D fopen ("/dev/full", "w")) =3D=3D NULL)
    exit (1);
  if (setvbuf (fp, buf, _IOFBF, sizeof buf) !=3D 0)
    exit (2);
  fprintf (fp, "%-1000000.65536f", 1.0);
}

--=20
You are receiving this mail because:
You are on the CC list for the bug.=