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elf: Fix LD_AUDIT for modules with invalid version (BZ#24122)

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The error handling patch for invalid audit modules version access
invalid memory:

elf/rtld.c:

1454               unsigned int (*laversion) (unsigned int);
1455               unsigned int lav;
1456               if  (err_str == NULL
1457                    && (laversion = largs.result) != NULL
1458                    && (lav = laversion (LAV_CURRENT)) > 0
1459                    && lav <= LAV_CURRENT)
1460                 {
[...]
1526               else
1527                 {
1528                   /* We cannot use the DSO, it does not have the
1529                      appropriate interfaces or it expects something
1530                      more recent.  */
1531 #ifndef NDEBUG
1532                   Lmid_t ns = dlmargs.map->l_ns;
1533 #endif
1534                   _dl_close (dlmargs.map);
1535
1536                   /* Make sure the namespace has been cleared entirely.  */
1537                   assert (GL(dl_ns)[ns]._ns_loaded == NULL);
1538                   assert (GL(dl_ns)[ns]._ns_nloaded == 0);
1539
1540                   GL(dl_tls_max_dtv_idx) = tls_idx;
1541                   goto not_loaded;
1542                 }

1431           const char *err_str = NULL;
1432           bool malloced;
1433           (void) _dl_catch_error (&objname, &err_str, &malloced, dlmopen_doit,
1434                                   &dlmargs);
1435           if (__glibc_unlikely (err_str != NULL))
1436             {
1437             not_loaded:
1438               _dl_error_printf ("\
1439 ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
1440                                 name, err_str);
1441               if (malloced)
1442                 free ((char *) err_str);
1443             }

On failure the err_str will be NULL and _dl_debug_vdprintf does not handle
it properly:

elf/dl-misc.c:
200             case 's':
201               /* Get the string argument.  */
202               iov[niov].iov_base = va_arg (arg, char *);
203               iov[niov].iov_len = strlen (iov[niov].iov_base);
204               if (prec != -1)
205                 iov[niov].iov_len = MIN ((size_t) prec, iov[niov].iov_len);
206               ++niov;
207               break;

This patch fixes the issues and improves the error message.

Checked on x86_64-linux-gnu and i686-linux-gnu

	[BZ #24122]
	* elf/Makefile (tests): Add tst-audit13.
	(modules-names): Add tst-audit13mod1.
	(tst-audit13.out, LDFLAGS-tst-audit13mod1.so, tst-audit13-ENV): New
	rule.
	* elf/rtld.c (dl_main): Handle invalid audit module version.
	* elf/tst-audit13.c: New file.
	* elf/tst-audit13mod1.c: Likewise.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Adhemerval Zanella 2019-01-23 11:42:54 -02:00
parent ee4d79026d
commit 8e889c5da3
5 changed files with 164 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
ChangeLog
View File

@ -1,3 +1,14 @@
2019-01-24 Adhemerval Zanella <adhemerval.zanella@linaro.org>
[BZ #24122]
* elf/Makefile (tests): Add tst-audit13.
(modules-names): Add tst-audit13mod1.
(tst-audit13.out, LDFLAGS-tst-audit13mod1.so, tst-audit13-ENV): New
rule.
* elf/rtld.c (dl_main): Handle invalid audit module version.
* elf/tst-audit13.c: New file.
* elf/tst-audit13mod1.c: Likewise.
2019-01-22 Samuel Thibault <samuel.thibault@ens-lyon.org>
* sysdeps/mach/hurd/faccessat.c (__faccessat_common): Check for errors

9
elf/Makefile
View File

@ -187,7 +187,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
tst-nodelete2 tst-audit11 tst-audit12 tst-dlsym-error tst-noload \
tst-latepthread tst-tls-manydynamic tst-nodelete-dlclose \
tst-debug1 tst-main1 tst-absolute-sym tst-absolute-zero tst-big-note \
tst-unwind-ctor tst-unwind-main
tst-unwind-ctor tst-unwind-main tst-audit13
# reldep9
tests-internal += loadtest unload unload2 circleload1 \
neededtest neededtest2 neededtest3 neededtest4 \
@ -275,7 +275,8 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
tst-latepthreadmod $(tst-tls-many-dynamic-modules) \
tst-nodelete-dlclose-dso tst-nodelete-dlclose-plugin \
tst-main1mod tst-libc_dlvsym-dso tst-absolute-sym-lib \
tst-absolute-zero-lib tst-big-note-lib tst-unwind-ctor-lib
tst-absolute-zero-lib tst-big-note-lib tst-unwind-ctor-lib \
tst-audit13mod1
# Most modules build with _ISOMAC defined, but those filtered out
# depend on internal headers.
modules-names-tests = $(filter-out ifuncmod% tst-libc_dlvsym-dso tst-tlsmod%,\
@ -1382,6 +1383,10 @@ tst-audit12-ENV = LD_AUDIT=$(objpfx)tst-auditmod12.so
$(objpfx)tst-audit12mod1.so: $(objpfx)tst-audit12mod2.so
LDFLAGS-tst-audit12mod2.so = -Wl,--version-script=tst-audit12mod2.map
$(objpfx)tst-audit13.out: $(objpfx)tst-audit13mod1.so
LDFLAGS-tst-audit13mod1.so = -Wl,-z,lazy
tst-audit13-ENV = LD_AUDIT=$(objpfx)tst-audit13mod1.so
# Override -z defs, so that we can reference an undefined symbol.
# Force lazy binding for the same reason.
LDFLAGS-tst-latepthreadmod.so = \

30
elf/rtld.c
View File

@ -1453,10 +1453,12 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
unsigned int (*laversion) (unsigned int);
unsigned int lav;
if (err_str == NULL
&& (laversion = largs.result) != NULL
&& (lav = laversion (LAV_CURRENT)) > 0
&& lav <= LAV_CURRENT)
if (err_str != NULL)
goto not_loaded;
if ((laversion = largs.result) != NULL
&& (lav = laversion (LAV_CURRENT)) > 0
&& lav <= LAV_CURRENT)
{
/* Allocate structure for the callback function pointers.
This call can never fail. */
@ -1538,7 +1540,25 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
assert (GL(dl_ns)[ns]._ns_nloaded == 0);
GL(dl_tls_max_dtv_idx) = tls_idx;
goto not_loaded;
if (GLRO(dl_debug_mask) & DL_DEBUG_FILES)
{
_dl_debug_printf ("\
\nfile=%s cannot be loaded as audit interface; ignored.\n", name);
if (laversion == NULL)
_dl_debug_printf (
" la_version function not found.\n");
else
{
if (lav == 0)
_dl_debug_printf (
" auditor requested to be ignored (returned version of 0).\n");
else
_dl_debug_printf (
" auditor disabled since expected version %d is greater than "
"supported version %d.\n",
lav, LAV_CURRENT);
}
}
}
}
}

28
elf/tst-audit13.c Normal file
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@ -0,0 +1,28 @@
/* Check for invalid audit version (BZ#24122).
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
<http://www.gnu.org/licenses/>. */
#include <stdio.h>
static int
do_test (void)
{
puts ("plt call");
return 0;
}
#include <support/test-driver.c>

93
elf/tst-audit13mod1.c Normal file
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@ -0,0 +1,93 @@
/* Check for invalid audit version (BZ#24122).
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
<http://www.gnu.org/licenses/>. */
#include <link.h>
#include <stdlib.h>
unsigned int
la_version (unsigned int version)
{
/* The audit specification says that a version of 0 or a version
greater than any version supported by the dynamic loader shall
cause the module to be ignored. */
return 0;
}
void
la_activity (uintptr_t *cookie, unsigned int flag)
{
exit (EXIT_FAILURE);
}
char *
la_objsearch (const char *name, uintptr_t *cookie, unsigned int flag)
{
exit (EXIT_FAILURE);
}
unsigned int
la_objopen (struct link_map *map, Lmid_t lmid, uintptr_t * cookie)
{
exit (EXIT_FAILURE);
}
void
la_preinit (uintptr_t * cookie)
{
exit (EXIT_FAILURE);
}
uintptr_t
#if __ELF_NATIVE_CLASS == 32
la_symbind32 (Elf32_Sym *sym, unsigned int ndx, uintptr_t *refcook,
uintptr_t *defcook, unsigned int *flags, const char *symname)
#else
la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
uintptr_t *defcook, unsigned int *flags, const char *symname)
#endif
{
exit (EXIT_FAILURE);
}
unsigned int
la_objclose (uintptr_t * cookie)
{
exit (EXIT_FAILURE);
}
#include <tst-audit.h>
#if (!defined (pltenter) || !defined (pltexit) || !defined (La_regs) \
|| !defined (La_retval) || !defined (int_retval))
# error "architecture specific code needed in sysdeps/CPU/tst-audit.h"
#endif
ElfW(Addr)
pltenter (ElfW(Sym) *sym, unsigned int ndx, uintptr_t *refcook,
uintptr_t *defcook, La_regs *regs, unsigned int *flags,
const char *symname, long int *framesizep)
{
exit (EXIT_FAILURE);
}
unsigned int
pltexit (ElfW(Sym) *sym, unsigned int ndx, uintptr_t *refcook,
uintptr_t *defcook, const La_regs *inregs, La_retval *outregs,
const char *symname)
{
exit (EXIT_FAILURE);
}