EmptyRealmCC.java

/*
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 * version 2 for more details (a copy is included in the LICENSE file that
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/*
 * @test
 * @bug 8048073
 * @summary Cannot read ccache entry with a realm-less service name
 * @modules java.security.jgss/sun.security.krb5
 *          java.security.jgss/sun.security.krb5.internal.ccache
 * @compile -XDignore.symbol.file EmptyRealmCC.java
 * @run main EmptyRealmCC
 */
import java.nio.file.Files;
import java.nio.file.Paths;

import sun.security.krb5.internal.ccache.CredentialsCache;

public class EmptyRealmCC {
    public static void main(String[] args) throws Exception {
        byte[] ccache = TimeInCCache.ccache;

        // The service name starts at 0x52:
        //
        //    0050:    00 00 00 02 00 00 00 0A 4D 41 58 49 2E 4C
        //             ----------- -----------
        //    0060: 4F 43 41 4C 00 00 00 06 6B 72 62 74 67 74 00 00
        //                      -----------                   -----
        //    0070: 00 0A 4D 41 58 49 2E 4C 4F 43 41 4C
        //          -----
        //
        // which contains 2 (the length of names), a 10-byte realm, a 6-byte
        // name[0], and a 10-byte name[1].

        // We will empty the realm, and pack the realm string to another
        // name (6-byte ".LOCAL"). Finally "krbtgt/MAXI.LOCAL@MAXI.LOCAL"
        // becomes ".LOCAL/krbtgt/MAXI.LOCAL@".

        // length of names is now 3
        ccache[0x55] = 3;
        // The empty realm
        System.arraycopy(new byte[4], 0, ccache, 0x56, 4);
        // Length of inserted name is 6
        System.arraycopy(new byte[]{0,0,0,6}, 0, ccache, 0x5A, 4);

        Files.write(Paths.get("tmpcc"), TimeInCCache.ccache);
        if (CredentialsCache.getInstance("tmpcc").getCredsList() != null) {
            throw new Exception("Nothing should be there");
        }
    }
}