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selftests/x86/vdso: Fix no-vDSO segfaults

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test_vdso would try to call a NULL pointer if the vDSO was missing.

vdso_restorer_32 hit a genuine failure: trying to use the
kernel-provided signal restorer doesn't work if the vDSO is missing.
Skip the test if the vDSO is missing, since the test adds no particular
value in that case.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/618ea7b8c55b10d08b1cb139e9a3a957934b8647.1584653439.git.luto@kernel.org
This commit is contained in:
Andy Lutomirski 2020-03-19 14:30:56 -07:00 committed by Borislav Petkov
parent fb33c6510d
commit 07f24dc95d
2 changed files with 20 additions and 0 deletions
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5
tools/testing/selftests/x86/test_vdso.c
View File

@ -259,6 +259,11 @@ static void test_one_clock_gettime(int clock, const char *name)
static void test_clock_gettime(void)
{
if (!vdso_clock_gettime) {
printf("[SKIP]\tNo vDSO, so skipping clock_gettime() tests\n");
return;
}
for (int clock = 0; clock < sizeof(clocknames) / sizeof(clocknames[0]);
clock++) {
test_one_clock_gettime(clock, clocknames[clock]);

15
tools/testing/selftests/x86/vdso_restorer.c
View File

@ -15,6 +15,7 @@
#include <err.h>
#include <stdio.h>
#include <dlfcn.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
@ -46,11 +47,23 @@ int main()
int nerrs = 0;
struct real_sigaction sa;
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) {
printf("[SKIP]\tFailed to find vDSO. Tests are not expected to work.\n");
return 0;
}
memset(&sa, 0, sizeof(sa));
sa.handler = handler_with_siginfo;
sa.flags = SA_SIGINFO;
sa.restorer = NULL; /* request kernel-provided restorer */
printf("[RUN]\tRaise a signal, SA_SIGINFO, sa.restorer == NULL\n");
if (syscall(SYS_rt_sigaction, SIGUSR1, &sa, NULL, 8) != 0)
err(1, "raw rt_sigaction syscall");
@ -63,6 +76,8 @@ int main()
nerrs++;
}
printf("[RUN]\tRaise a signal, !SA_SIGINFO, sa.restorer == NULL\n");
sa.flags = 0;
sa.handler = handler_without_siginfo;
if (syscall(SYS_sigaction, SIGUSR1, &sa, 0) != 0)