如何在Java中将SID转换为String，反之亦然？

Question

我正在用Java编写一个程序，使用Spring-LDAP。我需要实现一个方法，它应该通过SID搜索用户。出于这个原因，我使用了像"&((objectClass=User)(objectSid="+sid+"))"这样的过滤器。搜索不适用于字符串格式的sid，如"S-1-12-345677-5676743-223344-..."。

使用Apache Directory Studio，我可以使用像：(objectSid=\ff\01\03\04\1a\2b\...)这样的过滤器成功地查询我的AD LDAP数据库。这是十六进制格式的objectSid。

现在，在Java中，如何在程序中将SID从字符串转换为十六进制，反之亦然？

Answer 1

在Advapi32Util类中有convertSidToStringSid和convertStringSidToSid方法。

我不确定这是否是您需要的确切格式，但希望能让您更接近。

这里有一个描述SID格式的blog post，它可能对您有所帮助。

Answer 2

ho1 (使用Advapi32Util)类建议的解决方案有两个限制：

1. 它需要JNA库。
2. 它只有在Windows平台上运行时才能工作，因为它使用Windows-API。

因此，我编写了一个纯Java的类，它没有外部依赖项，可以在所有平台上工作。此类可以将安全标识符从它们的二进制转换为它们的文本表示，反之亦然。

如果使用Spring-LDAP，还可以使用LdapUtils类提供的方法，但是这些方法不会对SID的格式执行任何检查，因此可能会产生不正确的结果或意外的异常。

import java.nio.ByteBuffer;
import java.nio.ByteOrder;

public class SidConverter {

    private final static int MASK_8_BIT = 0xff;
    private final static long MASK_32_BIT = 0xffffffffL;
    private final static long MASK_48_BIT = 0xffffffffffffL;

    public static String bytesToString(byte[] bytes) {
        if (bytes.length < 8) {
            throw new IllegalArgumentException(
                    "Binary SID representation must have at least 8 bytes but passed byte array has only "
                            + bytes.length + " bytes.");
        }
        // The revision number is an unsigned 8-bit unsigned integer.
        int revision = bytes[0] & MASK_8_BIT;
        // The number of sub-authority parts is specified as an 8-bit unsigned
        // integer.
        int numberOfSubAuthorityParts = bytes[1] & MASK_8_BIT;
        if (bytes.length != 8 + numberOfSubAuthorityParts * 4) {
            throw new IllegalArgumentException(
                    "According to byte 1 of the SID it total length should be "
                            + (8 + 4 * numberOfSubAuthorityParts)
                            + " bytes, however its actual length is "
                            + bytes.length + " bytes.");
        }
        // The authority is a 48-bit unsigned integer stored in big-endian
        // format.
        long authority = ByteBuffer.wrap(bytes).getLong() & MASK_48_BIT;
        // The sub-authority consists of up to 255 32-bit unsigned integers in
        // little-endian format. The number of integers is specified by
        // numberOfSubAuthorityParts.
        int[] subAuthority = new int[numberOfSubAuthorityParts];
        ByteBuffer.wrap(bytes, 8, bytes.length - 8)
                .order(ByteOrder.LITTLE_ENDIAN).asIntBuffer().put(subAuthority);
        StringBuilder sb = new StringBuilder();
        sb.append("S-");
        sb.append(revision);
        sb.append("-");
        sb.append(authority);
        for (int subAuthorityPart : subAuthority) {
            sb.append("-");
            sb.append(subAuthorityPart & MASK_32_BIT);
        }
        return sb.toString();
    }

    public static byte[] stringToBytes(String sid) {
        if (!sid.startsWith("S-") && !sid.startsWith("s-")) {
            throw new IllegalArgumentException("Invalid SID \"" + sid
                    + "\": A valid SID must start with \"S-\".");
        }
        String[] parts = sid.split("-");
        if (parts.length < 3) {
            throw new IllegalArgumentException("Invalid SID \"" + sid
                    + "\": A valid SID must have at least two dashes.");
        }
        if (parts.length > MASK_8_BIT + 3) {
            throw new IllegalArgumentException("Invalid SID \"" + sid
                    + "\": A valid SID must not have more than 257 dashes.");
        }
        int revision;
        try {
            revision = Integer.parseInt(parts[1]);
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException(
                    "Invalid revision part in SID \""
                            + sid
                            + "\": The revision must be an integer number between 0 and 255.");
        }
        if (revision < 0 || revision > MASK_8_BIT) {
            throw new IllegalArgumentException(
                    "Invalid revision part in SID \""
                            + sid
                            + "\": The revision must be an integer number between 0 and 255.");
        }
        int numberOfSubAuthorityParts = parts.length - 3;
        long authority;
        try {
            authority = Long.parseLong(parts[2]);
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException(
                    "Invalid authority part in SID \""
                            + sid
                            + "\": The authority must be an integer number between 0 and 281474976710655.");
        }
        if (authority < 0 || authority > MASK_48_BIT) {
            throw new IllegalArgumentException(
                    "Invalid authority part in SID \""
                            + sid
                            + "\": The authority must be an integer number between 0 and 281474976710655.");
        }
        int[] subAuthority = new int[numberOfSubAuthorityParts];
        for (int i = 0; i < numberOfSubAuthorityParts; i++) {
            long subAuthorityPart;
            try {
                subAuthorityPart = Long.parseLong(parts[3 + i]);
            } catch (NumberFormatException e) {
                throw new IllegalArgumentException(
                        "Invalid sub-authority part in SID \""
                                + sid
                                + "\": The sub-authority parts must be integer numbers between 0 and 4294967295.");
            }
            if (subAuthorityPart < 0 || subAuthorityPart > MASK_32_BIT) {
                throw new IllegalArgumentException(
                        "Invalid sub-authority part in SID \""
                                + sid
                                + "\": The sub-authority parts must be integer numbers between 0 and 4294967295.");
            }
            subAuthority[i] = (int) subAuthorityPart;
        }
        byte[] bytes = new byte[8 + numberOfSubAuthorityParts * 4];
        // We have to write the authority first, otherwise it would overwrite
        // the revision and length bytes.
        ByteBuffer.wrap(bytes).putLong(authority);
        bytes[0] = (byte) revision;
        bytes[1] = (byte) numberOfSubAuthorityParts;
        ByteBuffer.wrap(bytes, 8, bytes.length - 8)
                .order(ByteOrder.LITTLE_ENDIAN).asIntBuffer().put(subAuthority);
        return bytes;
    }

}

Answer 3

使用InPlaceMsAdObjectSidValueEditor.java中的convertToString：

protected String convertToString( byte[] bytes )
{
    /*
     * The binary data structure, from http://msdn.microsoft.com/en-us/library/cc230371(PROT.10).aspx:
     *   byte[0] - Revision (1 byte): An 8-bit unsigned integer that specifies the revision level of the SID structure. This value MUST be set to 0x01.
     *   byte[1] - SubAuthorityCount (1 byte): An 8-bit unsigned integer that specifies the number of elements in the SubAuthority array. The maximum number of elements allowed is 15.
     *   byte[2-7] - IdentifierAuthority (6 bytes): A SID_IDENTIFIER_AUTHORITY structure that contains information, which indicates the authority under which the SID was created. It describes the entity that created the SID and manages the account.
     *               Six element arrays of 8-bit unsigned integers that specify the top-level authority 
     *               big-endian!
     *   and then - SubAuthority (variable): A variable length array of unsigned 32-bit integers that uniquely identifies a principal relative to the IdentifierAuthority. Its length is determined by SubAuthorityCount. 
     *              little-endian!
     */

    if ( bytes == null || bytes.length < 8 )
    {
        return Messages.getString( "InPlaceMsAdObjectSidValueEditor.InvalidSid" ); //$NON-NLS-1$
    }

    char[] hex = Hex.encodeHex( bytes );
    StringBuffer sb = new StringBuffer();

    // start with 'S'
    sb.append( 'S' );

    // revision
    int revision = Integer.parseInt( new String( hex, 0, 2 ), 16 );
    sb.append( '-' );
    sb.append( revision );

    // get count
    int count = Integer.parseInt( new String( hex, 2, 2 ), 16 );

    // check length
    if ( bytes.length != ( 8 + count * 4 ) )
    {
        return Messages.getString( "InPlaceMsAdObjectSidValueEditor.InvalidSid" ); //$NON-NLS-1$
    }

    // get authority, big-endian
    long authority = Long.parseLong( new String( hex, 4, 12 ), 16 );
    sb.append( '-' );
    sb.append( authority );

    // sub-authorities, little-endian
    for ( int i = 0; i < count; i++ )
    {
        StringBuffer rid = new StringBuffer();
        for ( int k = 3; k >= 0; k-- )
        {
            rid.append( hex[16 + ( i * 8 ) + ( k * 2 )] );
            rid.append( hex[16 + ( i * 8 ) + ( k * 2 ) + 1] );
        }

        long subAuthority = Long.parseLong( rid.toString(), 16 );
        sb.append( '-' );
        sb.append( subAuthority );
    }

    return sb.toString();
}

(来自Apache Directory Studio)