linux-kernel - [PATCH v2 13/14] selftests: vDSO: vdso_test_correctness: Use facilities from parse

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20251113-vdso-test-types-v2-13-0427eff70d08@linutronix.de>
Date: Thu, 13 Nov 2025 16:30:29 +0100
From: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
To: Andy Lutomirski <luto@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, 
 Vincenzo Frascino <vincenzo.frascino@....com>, 
 Shuah Khan <shuah@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org, 
 linux-kselftest@...r.kernel.org, 
 Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Subject: [PATCH v2 13/14] selftests: vDSO: vdso_test_correctness: Use
 facilities from parse_vdso.c

The soname from the vDSO is not a public API. Furthermore it requires
libc to implement dlsym() and friends.

Use the facilities from parse_vdso.c instead which uses the official
vDSO ABI to find it, aligned with the other vDSO selftests.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
---
 tools/testing/selftests/vDSO/Makefile              |  4 +--
 .../testing/selftests/vDSO/vdso_test_correctness.c | 30 ++++++++++------------
 2 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index 74dfc60e636edce91cc1df9643ca8aa008ecfe65..504b30155ae7c6da3065c4472384f54e5547332a 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -26,13 +26,11 @@ CFLAGS_NOLIBC := -nostdlib -nostdinc -ffreestanding -fno-asynchronous-unwind-tab
 $(OUTPUT)/vdso_test_gettimeofday: parse_vdso.c vdso_test_gettimeofday.c
 $(OUTPUT)/vdso_test_getcpu: parse_vdso.c vdso_test_getcpu.c
 $(OUTPUT)/vdso_test_abi: parse_vdso.c vdso_test_abi.c
+$(OUTPUT)/vdso_test_correctness: parse_vdso.c vdso_test_correctness.c
 
 $(OUTPUT)/vdso_standalone_test_x86: vdso_standalone_test_x86.c parse_vdso.c | headers
 $(OUTPUT)/vdso_standalone_test_x86: CFLAGS:=$(CFLAGS_NOLIBC) $(CFLAGS)
 
-$(OUTPUT)/vdso_test_correctness: vdso_test_correctness.c
-$(OUTPUT)/vdso_test_correctness: LDFLAGS += -ldl
-
 $(OUTPUT)/vdso_test_getrandom: parse_vdso.c
 $(OUTPUT)/vdso_test_getrandom: CFLAGS += -isystem $(top_srcdir)/tools/include \
                                          $(KHDR_INCLUDES) \
diff --git a/tools/testing/selftests/vDSO/vdso_test_correctness.c b/tools/testing/selftests/vDSO/vdso_test_correctness.c
index ac5fa3e906806c28d3238e6f4e767e370932c5d1..310688e1379511e2c564b460c6379cc00b7a5f9a 100644
--- a/tools/testing/selftests/vDSO/vdso_test_correctness.c
+++ b/tools/testing/selftests/vDSO/vdso_test_correctness.c
@@ -10,20 +10,22 @@
 #include <time.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <sys/auxv.h>
 #include <sys/syscall.h>
-#include <dlfcn.h>
 #include <string.h>
 #include <errno.h>
 #include <sched.h>
 #include <stdbool.h>
 #include <limits.h>
 
+#include "parse_vdso.h"
 #include "vdso_config.h"
 #include "vdso_call.h"
 #include "vdso_syscalls.h"
 #include "vdso_types.h"
 #include "../kselftest.h"
 
+static const char *version;
 static const char **name;
 
 #ifndef __NR_clock_gettime64
@@ -88,39 +90,32 @@ static void *vsyscall_getcpu(void)
 
 static void fill_function_pointers(void)
 {
-	void *vdso = dlopen("linux-vdso.so.1",
-			    RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
-	if (!vdso)
-		vdso = dlopen("linux-gate.so.1",
-			      RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
-	if (!vdso)
-		vdso = dlopen("linux-vdso32.so.1",
-			      RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
-	if (!vdso)
-		vdso = dlopen("linux-vdso64.so.1",
-			      RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
-	if (!vdso) {
+	unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
+
+	if (!sysinfo_ehdr) {
 		printf("[WARN]\tfailed to find vDSO\n");
 		return;
 	}
 
-	vdso_getcpu = (getcpu_t)dlsym(vdso, name[4]);
+	vdso_init_from_sysinfo_ehdr(sysinfo_ehdr);
+
+	vdso_getcpu = (getcpu_t)vdso_sym(version, name[4]);
 	if (!vdso_getcpu)
 		printf("Warning: failed to find getcpu in vDSO\n");
 
 	vgetcpu = (getcpu_t) vsyscall_getcpu();
 
-	vdso_clock_gettime = (vdso_clock_gettime_t)dlsym(vdso, name[1]);
+	vdso_clock_gettime = (vdso_clock_gettime_t)vdso_sym(version, name[1]);
 	if (!vdso_clock_gettime)
 		printf("Warning: failed to find clock_gettime in vDSO\n");
 
 #if defined(VDSO_32BIT)
-	vdso_clock_gettime64 = (vdso_clock_gettime64_t)dlsym(vdso, name[5]);
+	vdso_clock_gettime64 = (vdso_clock_gettime64_t)vdso_sym(version, name[5]);
 	if (!vdso_clock_gettime64)
 		printf("Warning: failed to find clock_gettime64 in vDSO\n");
 #endif
 
-	vdso_gettimeofday = (vdso_gettimeofday_t)dlsym(vdso, name[0]);
+	vdso_gettimeofday = (vdso_gettimeofday_t)vdso_sym(version, name[0]);
 	if (!vdso_gettimeofday)
 		printf("Warning: failed to find gettimeofday in vDSO\n");
 
@@ -398,6 +393,7 @@ static void test_gettimeofday(void)
 
 int main(int argc, char **argv)
 {
+	version = versions[VDSO_VERSION];
 	name = (const char **)&names[VDSO_NAMES];
 
 	fill_function_pointers();

-- 
2.51.0