ima: Evaluate error in init_ima()

mainline inclusion
from mainline-v5.8-rc1
commit e144d6b2
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I692HU
CVE: NA

--------------------------------

Evaluate error in init_ima() before register_blocking_lsm_notifier() and
return if not zero.

Cc: stable@vger.kernel.org # 5.3.x
Fixes: b1694245 ("ima: use the lsm policy update notifier")
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NJames Morris <jamorris@linux.microsoft.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NGUO Zihua <guozihua@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>

security/integrity/ima/ima_main.c

@@ -560,6 +560,9 @@ static int __init init_ima(void)
 		error = ima_init();
 	}
 
+	if (error)
+		return error;
+
 	error = register_blocking_lsm_notifier(&ima_lsm_policy_notifier);
 	if (error)
 		pr_warn("Couldn't register LSM notifier, error %d\n", error);