commit bc56ab1f4aa937665034373d3e320d0779a839aa
Author: Florian Weimer <fweimer@redhat.com>
Date: Tue Apr 26 14:23:02 2022 +0200
dlfcn: Do not use rtld_active () to determine ld.so state (bug 29078)
When audit modules are loaded, ld.so initialization is not yet
complete, and rtld_active () returns false even though ld.so is
mostly working. Instead, the static dlopen hook is used, but that
does not work at all because this is not a static dlopen situation.
Commit 466c1ea15f461edb8e3ffaf5d86d708876343bbf ("dlfcn: Rework
static dlopen hooks") moved the hook pointer into _rtld_global_ro,
which means that separate protection is not needed anymore and the
hook pointer can be checked directly.
The guard for disabling libio vtable hardening in _IO_vtable_check
should stay for now.
Fixes commit 8e1472d2c1e25e6eabc2059170731365f6d5b3d1 ("ld.so:
Examine GLRO to detect inactive loader [BZ #20204]").
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit 8dcb6d0af07fda3607b541857e4f3970a74ed55b)
diff --git a/dlfcn/dladdr.c b/dlfcn/dladdr.c
index 1cc305f0c46e7c3b..0d07ae1cd4dbb7a2 100644
--- a/dlfcn/dladdr.c
+++ b/dlfcn/dladdr.c
@@ -24,7 +24,7 @@ int
__dladdr (const void *address, Dl_info *info)
{
#ifdef SHARED
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->dladdr (address, info);
#endif
return _dl_addr (address, info, NULL, NULL);
diff --git a/dlfcn/dladdr1.c b/dlfcn/dladdr1.c
index 78560dbac208c316..93ce68c1d6067fe2 100644
--- a/dlfcn/dladdr1.c
+++ b/dlfcn/dladdr1.c
@@ -24,7 +24,7 @@ int
__dladdr1 (const void *address, Dl_info *info, void **extra, int flags)
{
#ifdef SHARED
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->dladdr1 (address, info, extra, flags);
#endif
diff --git a/dlfcn/dlclose.c b/dlfcn/dlclose.c
index 6a013a81bb648191..07ecb21bf7d43be4 100644
--- a/dlfcn/dlclose.c
+++ b/dlfcn/dlclose.c
@@ -24,7 +24,7 @@ int
__dlclose (void *handle)
{
#ifdef SHARED
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->dlclose (handle);
#endif
diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c
index 5047b140662bc33e..63da79c63000eef0 100644
--- a/dlfcn/dlerror.c
+++ b/dlfcn/dlerror.c
@@ -32,7 +32,7 @@ char *
__dlerror (void)
{
# ifdef SHARED
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->dlerror ();
# endif
diff --git a/dlfcn/dlinfo.c b/dlfcn/dlinfo.c
index c6f9a1da09ff8622..47d2daa96fa5986f 100644
--- a/dlfcn/dlinfo.c
+++ b/dlfcn/dlinfo.c
@@ -89,7 +89,7 @@ dlinfo_implementation (void *handle, int request, void *arg)
int
___dlinfo (void *handle, int request, void *arg)
{
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->dlinfo (handle, request, arg);
else
return dlinfo_implementation (handle, request, arg);
diff --git a/dlfcn/dlmopen.c b/dlfcn/dlmopen.c
index c171c8953da20fc7..2309224eb8484b1a 100644
--- a/dlfcn/dlmopen.c
+++ b/dlfcn/dlmopen.c
@@ -80,7 +80,7 @@ dlmopen_implementation (Lmid_t nsid, const char *file, int mode,
void *
___dlmopen (Lmid_t nsid, const char *file, int mode)
{
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->dlmopen (nsid, file, mode, RETURN_ADDRESS (0));
else
return dlmopen_implementation (nsid, file, mode, RETURN_ADDRESS (0));
diff --git a/dlfcn/dlopen.c b/dlfcn/dlopen.c
index e04b374b82b04337..9c59c751c4eaf7a7 100644
--- a/dlfcn/dlopen.c
+++ b/dlfcn/dlopen.c
@@ -75,7 +75,7 @@ dlopen_implementation (const char *file, int mode, void *dl_caller)
void *
___dlopen (const char *file, int mode)
{
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->dlopen (file, mode, RETURN_ADDRESS (0));
else
return dlopen_implementation (file, mode, RETURN_ADDRESS (0));
diff --git a/dlfcn/dlopenold.c b/dlfcn/dlopenold.c
index 9115501ac121eeca..c2f2a42194d50953 100644
--- a/dlfcn/dlopenold.c
+++ b/dlfcn/dlopenold.c
@@ -70,7 +70,7 @@ __dlopen_nocheck (const char *file, int mode)
mode |= RTLD_LAZY;
args.mode = mode;
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->dlopen (file, mode, RETURN_ADDRESS (0));
return _dlerror_run (dlopen_doit, &args) ? NULL : args.new;
diff --git a/dlfcn/dlsym.c b/dlfcn/dlsym.c
index 43044cf7bb95801e..d3861170a7631d01 100644
--- a/dlfcn/dlsym.c
+++ b/dlfcn/dlsym.c
@@ -62,7 +62,7 @@ dlsym_implementation (void *handle, const char *name, void *dl_caller)
void *
___dlsym (void *handle, const char *name)
{
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->dlsym (handle, name, RETURN_ADDRESS (0));
else
return dlsym_implementation (handle, name, RETURN_ADDRESS (0));
diff --git a/dlfcn/dlvsym.c b/dlfcn/dlvsym.c
index 9b76f9afa513e11f..3af02109c306b800 100644
--- a/dlfcn/dlvsym.c
+++ b/dlfcn/dlvsym.c
@@ -65,7 +65,7 @@ dlvsym_implementation (void *handle, const char *name, const char *version,
void *
___dlvsym (void *handle, const char *name, const char *version)
{
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->dlvsym (handle, name, version,
RETURN_ADDRESS (0));
else
diff --git a/elf/Makefile b/elf/Makefile
index fec6e23b5b625e3b..c89a6a58690646ee 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -376,6 +376,7 @@ tests += \
tst-audit24d \
tst-audit25a \
tst-audit25b \
+ tst-audit26 \
tst-auditmany \
tst-auxobj \
tst-auxobj-dlopen \
@@ -721,6 +722,7 @@ modules-names = \
tst-auditmod24c \
tst-auditmod24d \
tst-auditmod25 \
+ tst-auditmod26 \
tst-auxvalmod \
tst-big-note-lib \
tst-deep1mod1 \
@@ -2194,6 +2196,10 @@ $(objpfx)tst-audit25b: $(objpfx)tst-audit25mod1.so \
LDFLAGS-tst-audit25b = -Wl,-z,now
tst-audit25b-ARGS = -- $(host-test-program-cmd)
+$(objpfx)tst-audit26.out: $(objpfx)tst-auditmod26.so
+$(objpfx)tst-auditmod26.so: $(libsupport)
+tst-audit26-ENV = LD_AUDIT=$(objpfx)tst-auditmod26.so
+
# tst-sonamemove links against an older implementation of the library.
LDFLAGS-tst-sonamemove-linkmod1.so = \
-Wl,--version-script=tst-sonamemove-linkmod1.map \
diff --git a/elf/dl-libc.c b/elf/dl-libc.c
index d5bc4a277f4c6ef3..db4342a3256921f0 100644
--- a/elf/dl-libc.c
+++ b/elf/dl-libc.c
@@ -157,7 +157,7 @@ __libc_dlopen_mode (const char *name, int mode)
args.caller_dlopen = RETURN_ADDRESS (0);
#ifdef SHARED
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->libc_dlopen_mode (name, mode);
#endif
return dlerror_run (do_dlopen, &args) ? NULL : (void *) args.map;
@@ -185,7 +185,7 @@ __libc_dlsym (void *map, const char *name)
args.name = name;
#ifdef SHARED
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->libc_dlsym (map, name);
#endif
return (dlerror_run (do_dlsym, &args) ? NULL
@@ -199,7 +199,7 @@ void *
__libc_dlvsym (void *map, const char *name, const char *version)
{
#ifdef SHARED
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->libc_dlvsym (map, name, version);
#endif
@@ -222,7 +222,7 @@ int
__libc_dlclose (void *map)
{
#ifdef SHARED
- if (!rtld_active ())
+ if (GLRO (dl_dlfcn_hook) != NULL)
return GLRO (dl_dlfcn_hook)->libc_dlclose (map);
#endif
return dlerror_run (do_dlclose, map);
diff --git a/elf/tst-audit26.c b/elf/tst-audit26.c
new file mode 100644
index 0000000000000000..3f920e83bac247a5
--- /dev/null
+++ b/elf/tst-audit26.c
@@ -0,0 +1,35 @@
+/* Check the usability of <dlfcn.h> functions in audit modules.
+ Copyright (C) 2022 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 <gnu/lib-names.h>
+
+#include <support/check.h>
+#include <support/xdlfcn.h>
+
+static int
+do_test (void)
+{
+ /* Check that the audit module has been loaded. */
+ void *handle = xdlopen ("mapped to libc", RTLD_LOCAL | RTLD_NOW);
+ TEST_VERIFY (handle
+ == xdlopen (LIBC_SO, RTLD_LOCAL | RTLD_NOW | RTLD_NOLOAD));
+
+ return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/elf/tst-auditmod26.c b/elf/tst-auditmod26.c
new file mode 100644
index 0000000000000000..db7ba95abec20f53
--- /dev/null
+++ b/elf/tst-auditmod26.c
@@ -0,0 +1,104 @@
+/* Check the usability of <dlfcn.h> functions in audit modules. Audit module.
+ Copyright (C) 2022 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 <dlfcn.h>
+#include <first-versions.h>
+#include <gnu/lib-names.h>
+#include <link.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <support/check.h>
+#include <support/xdlfcn.h>
+
+unsigned int
+la_version (unsigned int current)
+{
+ /* Exercise various <dlfcn.h> functions. */
+
+ /* Check dlopen, dlsym, dlclose. */
+ void *handle = xdlopen (LIBM_SO, RTLD_LOCAL | RTLD_NOW);
+ void *ptr = xdlsym (handle, "sincos");
+ TEST_VERIFY (ptr != NULL);
+ ptr = dlsym (handle, "SINCOS");
+ TEST_VERIFY (ptr == NULL);
+ const char *message = dlerror ();
+ TEST_VERIFY (strstr (message, ": undefined symbol: SINCOS") != NULL);
+ ptr = dlsym (handle, "SINCOS");
+ TEST_VERIFY (ptr == NULL);
+ xdlclose (handle);
+ TEST_COMPARE_STRING (dlerror (), NULL);
+
+ handle = xdlopen (LIBC_SO, RTLD_LOCAL | RTLD_NOW | RTLD_NOLOAD);
+
+ /* Check dlvsym. _exit is unlikely to gain another symbol
+ version. */
+ TEST_VERIFY (xdlsym (handle, "_exit")
+ == xdlvsym (handle, "_exit", FIRST_VERSION_libc__exit_STRING));
+
+ /* Check dlinfo. */
+ {
+ void *handle2 = NULL;
+ TEST_COMPARE (dlinfo (handle, RTLD_DI_LINKMAP, &handle2), 0);
+ TEST_VERIFY (handle2 == handle);
+ }
+
+ /* Check dladdr and dladdr1. */
+ Dl_info info = { };
+ TEST_VERIFY (dladdr (&_exit, &info) != 0);
+ if (strcmp (info.dli_sname, "_Exit") != 0) /* _Exit is an alias. */
+ TEST_COMPARE_STRING (info.dli_sname, "_exit");
+ TEST_VERIFY (info.dli_saddr == &_exit);
+ TEST_VERIFY (strstr (info.dli_fname, LIBC_SO));
+ void *extra_info;
+ memset (&info, 0, sizeof (info));
+ TEST_VERIFY (dladdr1 (&_exit, &info, &extra_info, RTLD_DL_LINKMAP) != 0);
+ TEST_VERIFY (extra_info == handle);
+
+ /* Verify that dlmopen creates a new namespace. */
+ void *dlmopen_handle = xdlmopen (LM_ID_NEWLM, LIBC_SO, RTLD_NOW);
+ TEST_VERIFY (dlmopen_handle != handle);
+ memset (&info, 0, sizeof (info));
+ extra_info = NULL;
+ ptr = xdlsym (dlmopen_handle, "_exit");
+ TEST_VERIFY (dladdr1 (ptr, &info, &extra_info, RTLD_DL_LINKMAP) != 0);
+ TEST_VERIFY (extra_info == dlmopen_handle);
+ xdlclose (dlmopen_handle);
+
+ /* Terminate the process with an error state. This does not happen
+ automatically because the audit module state is not shared with
+ the main program. */
+ if (support_record_failure_is_failed ())
+ {
+ fflush (stdout);
+ fflush (stderr);
+ _exit (1);
+ }
+
+ return LAV_CURRENT;
+}
+
+char *
+la_objsearch (const char *name, uintptr_t *cookie, unsigned int flag)
+{
+ if (strcmp (name, "mapped to libc") == 0)
+ return (char *) LIBC_SO;
+ else
+ return (char *) name;
+}