libio: Set _vtable_offset before calling _IO_link_in [BZ #32148]

Since _IO_vtable_offset is used to detect the old binaries, set it
in _IO_old_file_init_internal before calling _IO_link_in which checks
_IO_vtable_offset.  Add a glibc 2.0 test with copy relocation on
_IO_stderr_@GLIBC_2.0 to verify that fopen won't cause memory corruption.
This fixes BZ #32148.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
This commit is contained in:
H.J. Lu 2024-09-07 08:32:32 -07:00
parent 97aa92263a
commit 9dfea3de7f
3 changed files with 95 additions and 1 deletions

View File

@ -293,11 +293,18 @@ endif
ifeq ($(build-shared),yes)
aux += oldfileops oldstdfiles
tests += \
tst-fopen-compat \
tst-stderr-compat \
# tests
tests-2.0 += \
tst-fopen-compat \
tst-stderr-compat \
# tests-2.0
tst-fopen-compat-ARGS = tst-fopen-compat.c
# Disable PIE to trigger copy relocation.
CFLAGS-tst-fopen-compat.c += -fno-pie
tst-fopen-compat-no-pie = yes
endif
shared-only-routines = oldiofopen oldiofdopen oldiofclose oldfileops \

View File

@ -103,9 +103,11 @@ _IO_old_file_init_internal (struct _IO_FILE_plus *fp)
fp->file._old_offset = _IO_pos_BAD;
fp->file._flags |= CLOSED_FILEBUF_FLAGS;
_IO_link_in (fp);
/* NB: _vtable_offset must be set before calling _IO_link_in since
_IO_vtable_offset is used to detect the old binaries. */
fp->file._vtable_offset = ((int) sizeof (struct _IO_FILE)
- (int) sizeof (struct _IO_FILE_complete));
_IO_link_in (fp);
fp->file._fileno = -1;
if (&_IO_stdin_used != NULL || !_IO_legacy_file ((FILE *) fp))

85
libio/tst-fopen-compat.c Normal file
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@ -0,0 +1,85 @@
/* Verify that fopen works with copy relocation on _IO_stderr_ in binaries
linked with glibc 2.0.
Copyright (C) 2024 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 <shlib-compat.h>
#if TEST_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
# define _LIBC
# define _IO_USE_OLD_IO_FILE
# include <stdio.h>
# include <string.h>
# include <unistd.h>
# include <limits.h>
# include <sys/stat.h>
# include <support/check.h>
struct _IO_jump_t;
struct _IO_FILE_plus
{
FILE file;
const struct _IO_jump_t *vtable;
};
extern struct _IO_FILE_plus _IO_stderr_;
compat_symbol_reference (libc, _IO_stderr_, _IO_stderr_, GLIBC_2_0);
compat_symbol_reference (libc, fopen, fopen, GLIBC_2_0);
compat_symbol_reference (libc, fclose, fclose, GLIBC_2_0);
static int
do_test (int argc, char *argv[])
{
static char filename[PATH_MAX + 1];
struct stat st;
char *name = NULL;
int i;
/* Try to trigger copy relocation. */
TEST_VERIFY_EXIT (_IO_stderr_.file._fileno == STDERR_FILENO);
for (i = 1; i < argc; i++)
{
name = argv[i];
if (stat (name, &st) == 0)
{
TEST_VERIFY_EXIT (strlen (name) <= PATH_MAX);
break;
}
}
TEST_VERIFY_EXIT (name != NULL);
strcpy (filename, name);
FILE *fp = fopen (filename, "r");
TEST_VERIFY_EXIT (strcmp (filename, name) == 0);
TEST_VERIFY_EXIT (fp != NULL);
TEST_VERIFY_EXIT (fclose (fp) == 0);
return 0;
}
#else
# include <support/test-driver.h>
static int
do_test (int argc, char *argv[])
{
return EXIT_UNSUPPORTED;
}
#endif
#define TEST_FUNCTION_ARGV do_test
#include <support/test-driver.c>