Updated DB schema and configured ACLs to use SIDs

1 files changed, 129 insertions, 0 deletions

diff --git a/SecurityIdentifier.cs b/SecurityIdentifier.cs
new file mode 100644
index 0000000..81d5ae7
--- /dev/null
+++ b/SecurityIdentifier.cs
@@ -0,0 +1,129 @@
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using System.Numerics;
+using System.Runtime.InteropServices;
+using System.Text.RegularExpressions;
+
+namespace HyperBooru;
+
+public enum WellKnownSidType {
+    NullSid,
+    WorldSid,
+    LocalSid,
+    CreatorOwnerSid,
+    CreatorGroupSid
+}
+
+public class SecurityIdentifier {
+    public SidStruct SidStruct { get; private init; }
+
+    private static readonly Regex SddlRegex =
+        new(@"^S(-[0-9]+){2,}$", RegexOptions.Compiled);
+
+    private static readonly Dictionary<WellKnownSidType, string> wellKnownSidTypes = new() {
+        { HyperBooru.WellKnownSidType.NullSid,         "S-1-0-0" },
+        { HyperBooru.WellKnownSidType.WorldSid,        "S-1-1-0" },
+        { HyperBooru.WellKnownSidType.LocalSid,        "S-1-2-0" },
+        { HyperBooru.WellKnownSidType.CreatorOwnerSid, "S-1-3-0" },
+        { HyperBooru.WellKnownSidType.CreatorGroupSid, "S-1-3-1" }
+    };
+
+    public SecurityIdentifier(WellKnownSidType wellKnownSidType)
+        : this(wellKnownSidTypes[wellKnownSidType]) {}
+
+    public SecurityIdentifier(string sddlForm) {
+        var match = SddlRegex.Match(sddlForm);
+        if(!match.Success)
+            throw new ArgumentException();
+
+        var values = match.Groups[1].Captures
+            .Select(v => uint.Parse(v.Value.Replace("-", "")))
+            .ToArray();
+
+        // Extremely roundabound way of converting a 32-bit
+        // integer to a 48-bit big-endian integer
+        byte[] identifierAuthority = BitConverter.GetBytes(values[1]);
+        if(BitConverter.IsLittleEndian)
+            Array.Reverse(identifierAuthority);
+        identifierAuthority = new byte[2]
+            .Concat(identifierAuthority)
+            .ToArray();
+
+        SidStruct = new SidStruct {
+            Revision            = (byte) values[0],
+            SubAuthorityCount   = (byte) (values.Count() - 2),
+            IdentifierAuthority = identifierAuthority,
+            SubAuthorities      = values.Skip(2).ToArray()
+        };
+    }
+
+    public SecurityIdentifier(SidStruct sidStruct) =>
+        SidStruct = sidStruct;
+
+    public SecurityIdentifier(byte[] binaryForm) {
+        IntPtr p = IntPtr.Zero;
+
+        try {
+            p = Marshal.AllocHGlobal(binaryForm.Length);
+            Marshal.Copy(binaryForm, 0, p, binaryForm.Length);
+            SidStruct = Marshal.PtrToStructure<SidStruct>(p);
+        } finally {
+            Marshal.FreeHGlobal(p);
+        }
+    }
+
+    public byte[] BinaryForm {
+        get {
+            var size = Marshal.SizeOf(typeof(SidStruct));
+            byte[] array = new byte[size];
+
+            IntPtr p = IntPtr.Zero;
+
+            try {
+                p = Marshal.AllocHGlobal(size);
+                Marshal.StructureToPtr(SidStruct, p, true);
+                Marshal.Copy(p, array, 0, size);
+            } finally {
+                Marshal.FreeHGlobal(p);
+            }
+
+            return array;
+        }
+    }
+
+    public override string ToString() {
+        var identifierAuthority = new BigInteger(SidStruct.IdentifierAuthority, true, true);
+        var subAuthorities = string.Join('-',SidStruct.SubAuthorities.Select(sa => sa.ToString()));
+        if(!string.IsNullOrEmpty(subAuthorities))
+            subAuthorities = "-" + subAuthorities;
+        return $"S-{SidStruct.Revision}-{identifierAuthority}{subAuthorities}";
+    }
+
+    public static bool operator ==(SecurityIdentifier x, SecurityIdentifier y) =>
+        x.SidStruct.Equals(y.SidStruct);
+
+    public static bool operator !=(SecurityIdentifier x, SecurityIdentifier y) =>
+        !(x == y);
+
+    public override bool Equals(object? obj) =>
+        obj is null ? false : this == (SecurityIdentifier) obj;
+
+    public override int GetHashCode() =>
+        SidStruct.GetHashCode();
+}
+
+[StructLayout(LayoutKind.Sequential)]
+public struct SidStruct {
+    public byte     Revision;
+    public byte     SubAuthorityCount;
+    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 6)]
+    public byte[]   IdentifierAuthority;
+    [MarshalAs(UnmanagedType.ByValArray)]
+    public uint[]   SubAuthorities;
+}
+
+public class SecurityIdentifierConverter : ValueConverter<SecurityIdentifier, byte[]> {
+    public SecurityIdentifierConverter()
+        : base(
+            v => v.BinaryForm,
+            v => new SecurityIdentifier(v)) {}
+}
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