glibc/libio/tst-bz24228.c
Dmitry V. Levin 21cc130b78 libio: do not attempt to free wide buffers of legacy streams [BZ #24228]
Commit a601b74d31 aka glibc-2.23~693
("In preparation for fixing BZ#16734, fix failure in misc/tst-error1-mem
when _G_HAVE_MMAP is turned off.") introduced a regression:
_IO_unbuffer_all now invokes _IO_wsetb to free wide buffers of all
files, including legacy standard files which are small statically
allocated objects that do not have wide buffers and the _mode member,
causing memory corruption.

Another memory corruption in _IO_unbuffer_all happens when -1
is assigned to the _mode member of legacy standard files that
do not have it.

[BZ #24228]
* libio/genops.c (_IO_unbuffer_all)
[SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)]: Do not attempt to free wide
buffers and access _IO_FILE_complete members of legacy libio streams.
* libio/tst-bz24228.c: New file.
* libio/tst-bz24228.map: Likewise.
* libio/Makefile [build-shared] (tests): Add tst-bz24228.
[build-shared] (generated): Add tst-bz24228.mtrace and
tst-bz24228.check.
[run-built-tests && build-shared] (tests-special): Add
$(objpfx)tst-bz24228-mem.out.
(LDFLAGS-tst-bz24228, tst-bz24228-ENV): New variables.
($(objpfx)tst-bz24228-mem.out): New rule.
2019-06-20 17:32:07 +00:00

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C

/* BZ #24228 check for memory corruption in legacy libio
Copyright (C) 2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <mcheck.h>
#include <support/test-driver.h>
static int
do_test (void)
{
mtrace ();
return 0;
}
#include <support/test-driver.c>