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Re: [PATCH] elf: Fix LD_AUDIT for modules with invalid version (BZ#24122)
On 23/01/2019 12:58, Carlos O'Donell wrote:
> On 1/23/19 9:07 AM, Adhemerval Zanella wrote:
>
> Thanks for fixing this!
>
> I'd like to see v2 please
>
> - Only output message when LD_DEBUG=all, since la_version returning 0
> or > LAV_CURRENT is not an error, but simply an API mandated situation
> where we ignore the module. I don't see that as an error.
>
> The Solaris docs say:
> "If the audit library return is zero, or a version that is greater
> than the rtld-audit interface the runtime linker supports, the audit
> library is discarded."
>
> Just discarded. It is up to the auditor to decide how it exposes to
> the user that it is running and operating as expected. We can provide
> feedback via LD_DEBUG=all.
Right, this rationale make sense. However I think this information is
relates to the 'files' option, instead of print when 'all' option are
selected.
>
> - Optional: use -Wl,z,lazy for the test, or remove the comment about
> the PLT call.
The idea is indeed to force PLT call, so the PLT audit stub is called
and tests explicit fails.
>
> - Suggested comment in tst-audit13mod1.c
Ack. Patch updated below.
---
[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.
--
diff --git a/elf/Makefile b/elf/Makefile
index 9cf5cd8dfd..c24d765730 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -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 = \
diff --git a/elf/rtld.c b/elf/rtld.c
index 5d97f41b7b..5abb345b1e 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -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 +1540,18 @@ 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
+ _dl_debug_printf (
+" invalid version '%u' (expected minimum of '%u').\n",
+ lav, LAV_CURRENT);
+ }
}
}
}
diff --git a/elf/tst-audit13.c b/elf/tst-audit13.c
new file mode 100644
index 0000000000..6f587baf58
--- /dev/null
+++ b/elf/tst-audit13.c
@@ -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>
diff --git a/elf/tst-audit13mod1.c b/elf/tst-audit13mod1.c
new file mode 100644
index 0000000000..598dab5ec4
--- /dev/null
+++ b/elf/tst-audit13mod1.c
@@ -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);
+}
--
2.17.1