selftests/exec: Test for empty string on NULL argv

Test for the NULL argv argument producing a single empty string on exec.

Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/lkml/20220201011637.2457646-1-keescook@chromium.org
This commit is contained in:
Kees Cook 2022-01-31 17:16:37 -08:00
parent dcd46d897a
commit 9132c3947b
2 changed files with 79 additions and 0 deletions

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@ -10,6 +10,7 @@ TEST_GEN_FILES := execveat.symlink execveat.denatured script subdir
TEST_FILES := Makefile
TEST_GEN_PROGS += recursion-depth
TEST_GEN_PROGS += null-argv
EXTRA_CLEAN := $(OUTPUT)/subdir.moved $(OUTPUT)/execveat.moved $(OUTPUT)/xxxxx* \
$(OUTPUT)/S_I*.test

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@ -0,0 +1,78 @@
// SPDX-License-Identifier: GPL-2.0-only
/* Test that empty argvs are swapped out for a single empty string. */
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "../kselftest.h"
#define FORK(exec) \
do { \
pid = fork(); \
if (pid == 0) { \
/* Child */ \
exec; /* Some kind of exec */ \
perror("# " #exec); \
return 1; \
} \
check_result(pid, #exec); \
} while (0)
void check_result(pid_t pid, const char *msg)
{
int wstatus;
if (pid == (pid_t)-1) {
perror("# fork");
ksft_test_result_fail("fork failed: %s\n", msg);
return;
}
if (waitpid(pid, &wstatus, 0) < 0) {
perror("# waitpid");
ksft_test_result_fail("waitpid failed: %s\n", msg);
return;
}
if (!WIFEXITED(wstatus)) {
ksft_test_result_fail("child did not exit: %s\n", msg);
return;
}
if (WEXITSTATUS(wstatus) != 0) {
ksft_test_result_fail("non-zero exit: %s\n", msg);
return;
}
ksft_test_result_pass("%s\n", msg);
}
int main(int argc, char *argv[], char *envp[])
{
pid_t pid;
static char * const args[] = { NULL };
static char * const str[] = { "", NULL };
/* argc counting checks */
if (argc < 1) {
fprintf(stderr, "# FAIL: saw argc == 0 (old kernel?)\n");
return 1;
}
if (argc != 1) {
fprintf(stderr, "# FAIL: unknown argc (%d)\n", argc);
return 1;
}
if (argv[0][0] == '\0') {
/* Good, we found a NULL terminated string at argv[0]! */
return 0;
}
/* Test runner. */
ksft_print_header();
ksft_set_plan(5);
FORK(execve(argv[0], str, NULL));
FORK(execve(argv[0], NULL, NULL));
FORK(execve(argv[0], NULL, envp));
FORK(execve(argv[0], args, NULL));
FORK(execve(argv[0], args, envp));
ksft_exit(ksft_cnt.ksft_pass == ksft_plan);
}