Re: [LTP] [PATCH v3 0/2] mount03: Convert to new API

[Petr Vorel <pvorel@suse.cz>]

Hi Xu,

> >> Why here is nobody_gid?

> >>> +		SAFE_SETGID(nobody_gid);
> >>> +		SAFE_SETREUID(-1, nobody_uid);

> >> What problem do you meet?

> > Using original code SAFE_SETREUID(nobody_uid, nobody_gid);
> > causes mount03_setuid_test to fail (exit 1).
> > The same code is in creat08.c, creat09.c, open10.c.
> > Did I answer your question?

> I look mount03_setuid_test code today, nosuid mount option should
> expect setuid failed when using a non-privileged user even this program 
> has set-user-id bit.

> Old api also think PASS when mount03_setuid_test exit 1

Ah, thanks for catching my error!

> So I think you should use  SAFE_SETREUID(nobody_uid, nobody_uid);
> and then use code as below:

> 	if (WIFEXITED(status)) {
> 		switch (WEXITSTATUS(status)) {
> 		case EXIT_FAILURE:
> 			tst_res(TPASS, "%s passed", TESTBIN);
> 			return;
> 		case EXIT_SUCCESS:
> 			tst_res(TFAIL, "%s failed", TESTBIN);
> 			return;
> 		default:
> 		case TBROK:
> 			break;
> 		}
I guess we can drop the default and TBROK part, right?
It's caught later by tst_brk(TBROK, ...)
> 	}

https://github.com/pevik/ltp/blob/22652d668a5ccbf3c7aa835c2dab6d0eb6058ba2/testcases/kernel/syscalls/mount/mount03.c#L74-L105

static void test_nosuid(void)
{
	pid_t pid;
	int status;
	struct stat st;

	SAFE_CP(TESTBIN, BIN_PATH);
	SAFE_STAT(BIN_PATH, &st);
	if (st.st_mode != SUID_MODE)
		SAFE_CHMOD(BIN_PATH, SUID_MODE);

	pid = SAFE_FORK();
	if (!pid) {
		SAFE_SETREUID(nobody_uid, nobody_uid);
		SAFE_EXECL(BIN_PATH, TESTBIN, NULL);
	}

	SAFE_WAITPID(pid, &status, 0);

	if (WIFEXITED(status)) {
		switch (WEXITSTATUS(status)) {
		case EXIT_FAILURE:
			tst_res(TPASS, "%s passed", TESTBIN);
			return;
		case EXIT_SUCCESS:
			tst_res(TFAIL, "%s failed", TESTBIN);
			return;
		}
	}

	tst_brk(TBROK, "Child %s", tst_strstatus(status));
}

Kind regards,
Petr

> Best Regards
> Yang Xu

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