/*
 * Copyright (c) 2018 Google, Inc.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program, if not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Regression test for commit 4dca6ea1d943 ("KEYS: add missing permission check
 * for request_key() destination"), or CVE-2017-17807.  This bug allowed adding
 * a key to a keyring given only Search permission to that keyring, rather than
 * the expected Write permission.
 *
 * We test for the bug by trying to add a negatively instantiated key, since
 * adding a negatively instantiated key using the bug was easy whereas adding a
 * positively instantiated key required exploiting a race condition.
 */

#include <errno.h>

#include "tst_test.h"
#include "lapi/keyctl.h"

static void do_test(void)
{
	key_serial_t keyid;
	int saved_errno;

	TEST(keyctl(KEYCTL_JOIN_SESSION_KEYRING, NULL));
	if (TST_RET < 0)
		tst_brk(TBROK | TTERRNO, "failed to join new session keyring");

	TEST(keyctl(KEYCTL_SETPERM, KEY_SPEC_SESSION_KEYRING,
		    KEY_POS_SEARCH|KEY_POS_READ|KEY_POS_VIEW));
	if (TST_RET < 0) {
		tst_brk(TBROK | TTERRNO,
			"failed to set permissions on session keyring");
	}

	TEST(keyctl(KEYCTL_SET_REQKEY_KEYRING,
		    KEY_REQKEY_DEFL_SESSION_KEYRING));
	if (TST_RET < 0) {
		tst_brk(TBROK | TTERRNO,
			"failed to set request-key default keyring");
	}

	TEST(keyctl(KEYCTL_READ, KEY_SPEC_SESSION_KEYRING,
		    &keyid, sizeof(keyid)));
	if (TST_RET < 0)
		tst_brk(TBROK | TTERRNO, "failed to read from session keyring");
	if (TST_RET != 0)
		tst_brk(TBROK, "session keyring is not empty");

	TEST(request_key("user", "desc", "callout_info", 0));
	if (TST_RET != -1)
		tst_brk(TBROK, "request_key() unexpectedly succeeded");
	saved_errno = TST_ERR;

	TEST(keyctl(KEYCTL_READ, KEY_SPEC_SESSION_KEYRING,
		    &keyid, sizeof(keyid)));
	if (TST_RET < 0)
		tst_brk(TBROK | TTERRNO, "failed to read from session keyring");
	if (TST_RET != 0)
		tst_brk(TFAIL, "added key to keyring without permission");

	TST_ERR = saved_errno;
	if (TST_ERR == EACCES) {
		tst_res(TPASS, "request_key() failed with EACCES as expected");
	} else {
		tst_res(TBROK | TTERRNO,
			"request_key() failed with unexpected error code");
	}
}

static struct tst_test test = {
	.test_all = do_test,
};