On 11/11/2021 14:50, Florian Weimer wrote:
> * Adhemerval Zanella:
>
>> +static int
>> +handle_restart (void)
>> +{
>> + fprintf (stderr, "vdso: %" PRIxPTR "\n", vdso_addr);
>> + return 0;
>> +}
>> +
>> +static unsigned long int
>> +parse_address (const char *str)
>> +{
>> + char *endptr;
>> + long int ret;
>> + errno = 0;
>> + ret = strtol (str, &endptr, 10);
>> + TEST_COMPARE (errno, 0);
>> + TEST_VERIFY (ret >= 0 && ret <= INT_MAX);
>> + return ret;
>> +}
>
> Doesn't parse_address always produce 0 fpr PRIxPTR values because
> reading stops at the 'x'? Maybe use printf and scanf with %p instead?
It is indeed better, I will change it.
>
> The rest of the patch looks okay to me. Placement of the audit call
> seems reasonable.
>
> Thanks,
> Florian
>
@@ -229,6 +229,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
tst-audit19 \
tst-audit20 \
tst-audit21 \
+ tst-audit22 \
tst-single_threaded tst-single_threaded-pthread \
tst-tls-ie tst-tls-ie-dlmopen argv0test \
tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \
@@ -321,6 +322,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
tst-auditmod19 \
tst-auditmod20 tst-audit20mod \
tst-auditmod21 \
+ tst-auditmod22 \
$(if $(CXX),tst-unique3lib tst-unique3lib2 tst-unique4lib \
tst-nodelete-uniquemod tst-nodelete-rtldmod \
tst-nodelete-zmod \
@@ -1576,6 +1578,9 @@ tst-audit20-ARGS = -- $(host-test-program-cmd)
$(objpfx)tst-audit21.out: $(objpfx)tst-auditmod21.so
tst-audit21-ENV = LD_AUDIT=$(objpfx)tst-auditmod21.so
+$(objpfx)tst-audit22.out: $(objpfx)tst-auditmod22.so
+tst-audit22-ARGS = -- $(host-test-program-cmd)
+
# tst-sonamemove links against an older implementation of the library.
LDFLAGS-tst-sonamemove-linkmod1.so = \
-Wl,--version-script=tst-sonamemove-linkmod1.map \
@@ -59,16 +59,19 @@ _dl_new_object (char *realname, const char *libname, int type,
{
#ifdef SHARED
unsigned int naudit;
- if (__glibc_unlikely ((mode & __RTLD_OPENEXEC) != 0))
+ if (__glibc_unlikely ((mode & (__RTLD_OPENEXEC | __RTLD_VDSO)) != 0))
{
- assert (type == lt_executable);
- assert (nsid == LM_ID_BASE);
+ if (mode & __RTLD_OPENEXEC)
+ {
+ assert (type == lt_executable);
+ assert (nsid == LM_ID_BASE);
- /* Ignore the specified libname for the main executable. It is
- only known with an explicit loader invocation. */
- libname = "";
+ /* Ignore the specified libname for the main executable. It is
+ only known with an explicit loader invocation. */
+ libname = "";
+ }
- /* We create the map for the executable before we know whether
+ /* We create the map for the executable and vDSO before we know whether
we have auditing libraries and if yes, how many. Assume the
worst. */
naudit = DL_NNS;
@@ -1879,6 +1879,13 @@ dl_main (const ElfW(Phdr) *phdr,
assert (i == npreloads);
}
+#ifdef NEED_DL_SYSINFO_DSO
+ /* Now that the audit modules are opened, call la_objopen() for the
+ vDSO. */
+ if (GLRO(dl_sysinfo_map) != NULL)
+ _dl_audit_objopen (GLRO(dl_sysinfo_map), LM_ID_BASE, true);
+#endif
+
/* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD
specified some libraries to load, these are inserted before the actual
dependencies in the executable's searchlist for symbol resolution. */
@@ -30,7 +30,7 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
We just want our data structures to describe it as if we had just
mapped and relocated it normally. */
struct link_map *l = _dl_new_object ((char *) "", "", lt_library, NULL,
- 0, LM_ID_BASE);
+ __RTLD_VDSO, LM_ID_BASE);
if (__glibc_likely (l != NULL))
{
l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso)
new file mode 100644
@@ -0,0 +1,119 @@
+/* Check DTAUDIT and vDSO interaction.
+ Copyright (C) 2021 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 <errno.h>
+#include <getopt.h>
+#include <limits.h>
+#include <inttypes.h>
+#include <string.h>
+#include <stdlib.h>
+#include <support/capture_subprocess.h>
+#include <support/check.h>
+#include <support/xstdio.h>
+#include <support/support.h>
+#include <sys/auxv.h>
+
+static int restart;
+#define CMDLINE_OPTIONS \
+ { "restart", no_argument, &restart, 1 },
+
+static uintptr_t vdso_addr;
+
+static int
+handle_restart (void)
+{
+ fprintf (stderr, "vdso: %" PRIxPTR "\n", vdso_addr);
+ return 0;
+}
+
+static unsigned long int
+parse_address (const char *str)
+{
+ char *endptr;
+ long int ret;
+ errno = 0;
+ ret = strtol (str, &endptr, 10);
+ TEST_COMPARE (errno, 0);
+ TEST_VERIFY (ret >= 0 && ret <= INT_MAX);
+ return ret;
+}
+
+static inline bool
+startswith (const char *str, const char *pre)
+{
+ size_t lenpre = strlen (pre);
+ size_t lenstr = strlen (str);
+ return lenstr < lenpre ? false : memcmp (pre, str, lenpre) == 0;
+}
+
+static int
+do_test (int argc, char *argv[])
+{
+ vdso_addr = getauxval (AT_SYSINFO_EHDR);
+ if (vdso_addr == 0)
+ FAIL_UNSUPPORTED ("getauxval (AT_SYSINFO_EHDR) returned 0");
+
+ /* We must have either:
+ - One our fource parameters left if called initially:
+ + path to ld.so optional
+ + "--library-path" optional
+ + the library path optional
+ + the application name */
+
+ if (restart)
+ return handle_restart ();
+
+
+ char *spargv[9];
+ int i = 0;
+ for (; i < argc - 1; i++)
+ spargv[i] = argv[i + 1];
+ spargv[i++] = (char *) "--direct";
+ spargv[i++] = (char *) "--restart";
+ spargv[i] = NULL;
+
+ setenv ("LD_AUDIT", "tst-auditmod22.so", 0);
+ struct support_capture_subprocess result
+ = support_capture_subprogram (spargv[0], spargv);
+ support_capture_subprocess_check (&result, "tst-audit22", 0, sc_allow_stderr);
+
+ unsigned long vdso_process = 0;
+ unsigned long vdso_audit = 0;
+
+ FILE *out = fmemopen (result.err.buffer, result.err.length, "r");
+ TEST_VERIFY (out != NULL);
+ char *buffer = NULL;
+ size_t buffer_length = 0;
+ while (xgetline (&buffer, &buffer_length, out))
+ {
+ if (startswith (buffer, "vdso: "))
+ vdso_process = parse_address (buffer + strlen ("vdso: "));
+ else if (startswith (buffer, "vdso found: "))
+ vdso_audit = parse_address (buffer + strlen ("vdso found: "));
+ }
+
+ TEST_COMPARE (vdso_process, vdso_audit);
+
+ free (buffer);
+ xfclose (out);
+
+ return 0;
+}
+
+#define TEST_FUNCTION_ARGV do_test
+#include <support/test-driver.c>
new file mode 100644
@@ -0,0 +1,37 @@
+/* Check DTAUDIT and vDSO interaction.
+ Copyright (C) 2021 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 <link.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <sys/auxv.h>
+
+unsigned int
+la_version (unsigned int version)
+{
+ return LAV_CURRENT;
+}
+
+unsigned int
+la_objopen (struct link_map *map, Lmid_t lmid, uintptr_t *cookie)
+{
+ if (map->l_addr == getauxval (AT_SYSINFO_EHDR))
+ fprintf (stderr, "vdso found: %" PRIxPTR "\n", (uintptr_t) map->l_addr);
+
+ return 0;
+}
@@ -12,6 +12,7 @@
#define __RTLD_AUDIT 0x08000000
#define __RTLD_SECURE 0x04000000 /* Apply additional security checks. */
#define __RTLD_NOIFUNC 0x02000000 /* Suppress calling ifunc functions. */
+#define __RTLD_VDSO 0x01000000
#define __LM_ID_CALLER -2