CommonAce.cs

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using System.Diagnostics.CodeAnalysis;
using System.Security.Principal;
 
namespace System.Security.AccessControl;
 
public sealed class CommonAce : QualifiedAce
{
    public override int BinaryLength => 8 + base.SecurityIdentifier.BinaryLength + base.OpaqueLength;
 
    internal override int MaxOpaqueLengthInternal => MaxOpaqueLength(base.IsCallback);
 
    public CommonAce(AceFlags flags, AceQualifier qualifier, int accessMask, SecurityIdentifier sid, bool isCallback, byte[]? opaque)
        : base(TypeFromQualifier(isCallback, qualifier), flags, accessMask, sid, opaque)
    {
    }
 
    private static AceType TypeFromQualifier(bool isCallback, AceQualifier qualifier)
    {
        return qualifier switch
        {
            AceQualifier.AccessAllowed => isCallback ? AceType.AccessAllowedCallback : AceType.AccessAllowed, 
            AceQualifier.AccessDenied => (!isCallback) ? AceType.AccessDenied : AceType.AccessDeniedCallback, 
            AceQualifier.SystemAudit => isCallback ? AceType.SystemAuditCallback : AceType.SystemAudit, 
            AceQualifier.SystemAlarm => isCallback ? AceType.SystemAlarmCallback : AceType.SystemAlarm, 
            _ => throw new ArgumentOutOfRangeException("qualifier", System.SR.ArgumentOutOfRange_Enum), 
        };
    }
 
    internal static bool ParseBinaryForm(byte[] binaryForm, int offset, out AceQualifier qualifier, out int accessMask, [NotNullWhen(true)] out SecurityIdentifier sid, out bool isCallback, out byte[] opaque)
    {
        GenericAce.VerifyHeader(binaryForm, offset);
        if (binaryForm.Length - offset >= 8 + System.Security.Principal.SecurityIdentifier.MinBinaryLength)
        {
            AceType aceType = (AceType)binaryForm[offset];
            if (aceType == AceType.AccessAllowed || aceType == AceType.AccessDenied || aceType == AceType.SystemAudit || aceType == AceType.SystemAlarm)
            {
                isCallback = false;
            }
            else
            {
                if (aceType != AceType.AccessAllowedCallback && aceType != AceType.AccessDeniedCallback && aceType != AceType.SystemAuditCallback && aceType != AceType.SystemAlarmCallback)
                {
                    goto IL_0114;
                }
                isCallback = true;
            }
            if (aceType == AceType.AccessAllowed || aceType == AceType.AccessAllowedCallback)
            {
                qualifier = AceQualifier.AccessAllowed;
            }
            else if (aceType == AceType.AccessDenied || aceType == AceType.AccessDeniedCallback)
            {
                qualifier = AceQualifier.AccessDenied;
            }
            else if (aceType == AceType.SystemAudit || aceType == AceType.SystemAuditCallback)
            {
                qualifier = AceQualifier.SystemAudit;
            }
            else
            {
                if (aceType != AceType.SystemAlarm && aceType != AceType.SystemAlarmCallback)
                {
                    goto IL_0114;
                }
                qualifier = AceQualifier.SystemAlarm;
            }
            int num = offset + 4;
            int num2 = 0;
            accessMask = binaryForm[num] + (binaryForm[num + 1] << 8) + (binaryForm[num + 2] << 16) + (binaryForm[num + 3] << 24);
            num2 += 4;
            sid = new SecurityIdentifier(binaryForm, num + num2);
            opaque = null;
            int num3 = (binaryForm[offset + 3] << 8) + binaryForm[offset + 2];
            if (num3 % 4 == 0)
            {
                int num4 = num3 - 4 - 4 - (byte)sid.BinaryLength;
                if (num4 > 0)
                {
                    opaque = new byte[num4];
                    for (int i = 0; i < num4; i++)
                    {
                        opaque[i] = binaryForm[offset + num3 - num4 + i];
                    }
                }
                return true;
            }
        }
        goto IL_0114;
        IL_0114:
        qualifier = AceQualifier.AccessAllowed;
        accessMask = 0;
        sid = null;
        isCallback = false;
        opaque = null;
        return false;
    }
 
    public static int MaxOpaqueLength(bool isCallback)
    {
        return 65527 - System.Security.Principal.SecurityIdentifier.MaxBinaryLength;
    }
 
    public override void GetBinaryForm(byte[] binaryForm, int offset)
    {
        MarshalHeader(binaryForm, offset);
        int num = offset + 4;
        int num2 = 0;
        binaryForm[num] = (byte)base.AccessMask;
        binaryForm[num + 1] = (byte)(base.AccessMask >> 8);
        binaryForm[num + 2] = (byte)(base.AccessMask >> 16);
        binaryForm[num + 3] = (byte)(base.AccessMask >> 24);
        num2 += 4;
        base.SecurityIdentifier.GetBinaryForm(binaryForm, num + num2);
        num2 += base.SecurityIdentifier.BinaryLength;
        if (GetOpaque() != null)
        {
            if (base.OpaqueLength > MaxOpaqueLengthInternal)
            {
                throw new InvalidOperationException();
            }
            GetOpaque().CopyTo(binaryForm, num + num2);
        }
    }
}