KEYS: encrypted: Add check for strsep

Add check for strsep() in order to transfer the error.

Fixes: cd3bc044 ("KEYS: encrypted: Instantiate key with user-provided decrypted data")
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

security/keys/encrypted-keys/encrypted.c

@@ -237,6 +237,10 @@ static int datablob_parse(char *datablob, const char **format,
 			break;
 		}
 		*decrypted_data = strsep(&datablob, " \t");
+		if (!*decrypted_data) {
+			pr_info("encrypted_key: decrypted_data is missing\n");
+			break;
+		}
 		ret = 0;
 		break;
 	case Opt_load: