Apply section CTR and do a pfs0 superblock validity check

hactoolnet/Program.cs

@@ -9,8 +9,8 @@ namespace hactoolnet
     {
         static void Main(string[] args)
         {
-            ReadNca();
+            //ReadNca();
-            //ListSdfs(args);
+            ListSdfs(args);
         }
 
         private static void ListSdfs(string[] args)
@@ -24,16 +24,16 @@ namespace hactoolnet
             ListTitles(sdfs);
 
             //DecryptNax0(sdfs, "C0628FB07A89E9050BDA258F74868E8D");
-            DecryptTitle(sdfs, 0x010025400AECE000);
+            //DecryptTitle(sdfs, 0x010023900AEE0000);
         }
 
         static void ReadNca()
         {
             var keyset = ExternalKeys.ReadKeyFile("keys.txt", "titlekeys.txt");
-            using (var file = new FileStream("acc9da939a8e0b339aa3be3d409d9ada.nca", FileMode.Open, FileAccess.Read))
+            using (var file = new FileStream("bf8b106a2e68df3c3f1694636423585a.nca", FileMode.Open, FileAccess.Read))
             {
                 var nca = new Nca(keyset, file, false);
-                var romfs = nca.OpenSection(0);
+                var romfs = nca.OpenSection(0, false);
 
                 using (var output = new FileStream("romfs_net", FileMode.Create))
                 {
@@ -77,7 +77,7 @@ namespace hactoolnet
 
         static SdFs LoadSdFs(string[] args)
         {
-            var keyset = ExternalKeys.ReadKeyFile(args[0]);
+            var keyset = ExternalKeys.ReadKeyFile(args[0], "titlekeys.txt");
             keyset.SetSdSeed(args[1].ToBytes());
             var sdfs = new SdFs(keyset, args[2]);
             return sdfs;
@@ -103,6 +103,16 @@ namespace hactoolnet
                         $"    {content.NcaId.ToHexString()}.nca {content.Type} {Util.GetBytesReadable(content.Size)}");
                 }
 
+                foreach (var nca in title.Ncas)
+                {
+                    Console.WriteLine($"      {nca.HasRightsId} {nca.NcaId} {nca.Header.ContentType}");
+
+                    foreach (var sect in nca.Sections)
+                    {
+                        Console.WriteLine($"        {sect.SectionNum} {sect.Type} {sect.Header.CryptType} {sect.SuperblockHashValidity}");
+                    }
+                }
+
                 Console.WriteLine("");
             }
         }

libhac/AesCtrStream.cs

@@ -24,6 +24,7 @@
 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 // THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+using System;
 using System.IO;
 using System.Security.Cryptography;
 using libhac.XTSSharp;
@@ -40,6 +41,7 @@ namespace libhac
         /// </summary>
         public const int DefaultSectorSize = 16;
 
+        private readonly byte[] _initialCounter;
         private readonly long _counterOffset;
         private readonly byte[] _tempBuffer;
         private readonly Aes _aes;
@@ -62,9 +64,16 @@ namespace libhac
         /// <param name="offset">Offset to start at in the input stream</param>
         /// <param name="length">The length of the created stream</param>
         /// <param name="counterOffset">Offset to add to the counter</param>
-        public AesCtrStream(Stream baseStream, byte[] key, long offset, long length, long counterOffset)
+        /// <param name="ctrHi">The value of the upper 64 bits of the counter</param>
+        public AesCtrStream(Stream baseStream, byte[] key, long offset, long length, long counterOffset, byte[] ctrHi = null)
             : base(baseStream, 0x10, offset)
         {
+            _initialCounter = new byte[0x10];
+            if (ctrHi != null)
+            {
+                Array.Copy(ctrHi, _initialCounter, 8);
+            }
+
             _counterOffset = counterOffset;
             Length = length;
             _tempBuffer = new byte[0x10];
@@ -80,7 +89,7 @@ namespace libhac
 
         private CounterModeCryptoTransform CreateDecryptor()
         {
-            var dec = new CounterModeCryptoTransform(_aes, _aes.Key, new byte[0x10]);
+            var dec = new CounterModeCryptoTransform(_aes, _aes.Key, _initialCounter ?? new byte[0x10]);
             dec.UpdateCounter(_counterOffset + Position);
             return dec;
         }

libhac/Nca.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Security.Cryptography;
 using libhac.XTSSharp;
 
 namespace libhac
@@ -34,15 +35,24 @@ namespace libhac
             {
                 DecryptKeyArea(keyset);
             }
+            else
+            {
+                if (keyset.TitleKeys.TryGetValue(Header.RightsId, out var titleKey))
+                {
+                    Crypto.DecryptEcb(keyset.titlekeks[CryptoType], titleKey, DecryptedKeys[2], 0x10);
+                }
+            }
 
             for (int i = 0; i < 4; i++)
             {
                 var section = ParseSection(i);
-                if (section != null) Sections.Add(section);
+                if (section == null) continue;
+                Sections.Add(section);
+                ValidateSuperblockHash(i);
             }
         }
 
-        public Stream OpenSection(int index)
+        public Stream OpenSection(int index, bool raw)
         {
             if (index >= Sections.Count) throw new ArgumentOutOfRangeException(nameof(index));
             var sect = Sections[index];
@@ -50,6 +60,8 @@ namespace libhac
             long offset = sect.Offset;
             long size = sect.Size;
 
+            if (!raw)
+            {
                 switch (sect.Header.FsType)
                 {
                     case SectionFsType.Pfs0:
@@ -57,12 +69,14 @@ namespace libhac
                         size = sect.Pfs0.Pfs0Size;
                         break;
                     case SectionFsType.Romfs:
-                    offset = sect.Offset + (long)sect.Header.Romfs.IvfcHeader.LevelHeaders[Romfs.IvfcMaxLevel - 1].LogicalOffset;
+                        offset = sect.Offset + (long)sect.Header.Romfs.IvfcHeader.LevelHeaders[Romfs.IvfcMaxLevel - 1]
+                                     .LogicalOffset;
                         size = (long)sect.Header.Romfs.IvfcHeader.LevelHeaders[Romfs.IvfcMaxLevel - 1].HashDataSize;
                         break;
                     default:
                         throw new ArgumentOutOfRangeException();
                 }
+            }
 
             Stream.Position = offset;
 
@@ -73,7 +87,7 @@ namespace libhac
                 case SectionCryptType.XTS:
                     break;
                 case SectionCryptType.CTR:
-                    return new RandomAccessSectorStream(new AesCtrStream(Stream, DecryptedKeys[2], offset, size, offset), false);
+                    return new RandomAccessSectorStream(new AesCtrStream(Stream, DecryptedKeys[2], offset, size, offset, sect.Header.Ctr), false);
                 case SectionCryptType.BKTR:
                     break;
                 default:
@@ -128,6 +142,47 @@ namespace libhac
             return sect;
         }
 
+        private void ValidateSuperblockHash(int index)
+        {
+            if (index >= Sections.Count) throw new ArgumentOutOfRangeException(nameof(index));
+            var sect = Sections[index];
+            var stream = OpenSection(index, true);
+
+            byte[] expected = null;
+            byte[] actual;
+            long offset = 0;
+            long size = 0;
+
+            switch (sect.Type)
+            {
+                case SectionType.Invalid:
+                    break;
+                case SectionType.Pfs0:
+                    var pfs0 = sect.Header.Pfs0;
+                    expected = pfs0.MasterHash;
+                    offset = pfs0.HashTableOffset;
+                    size = pfs0.HashTableSize;
+                    break;
+                case SectionType.Romfs:
+                    break;
+                case SectionType.Bktr:
+                    break;
+            }
+
+            if (expected == null) return;
+
+            var hashTable = new byte[size];
+            stream.Position = offset;
+            stream.Read(hashTable, 0, hashTable.Length);
+
+            using (SHA256 hash = SHA256.Create())
+            {
+                actual = hash.ComputeHash(hashTable);
+            }
+
+            sect.SuperblockHashValidity = Util.ArraysEqual(expected, actual) ? Validity.Valid : Validity.Invalid;
+        }
+
         public void Dispose()
         {
             if (!KeepOpen)
@@ -145,6 +200,7 @@ namespace libhac
         public int SectionNum { get; set; }
         public long Offset { get; set; }
         public long Size { get; set; }
+        public Validity SuperblockHashValidity { get; set; }
 
         public Pfs0Superblock Pfs0 { get; set; }
     }

libhac/NcaStructs.cs

@@ -1,4 +1,5 @@
 using System.IO;
+using System.Linq;
 
 namespace libhac
 {
@@ -96,7 +97,7 @@ namespace libhac
         public Pfs0Superblock Pfs0;
         public RomfsSuperblock Romfs;
         public BktrSuperblock Bktr;
-        public ulong Ctr;
+        public byte[] Ctr;
 
         public NcaFsHeader(BinaryReader reader)
         {
@@ -126,7 +127,7 @@ namespace libhac
                 }
             }
 
-            Ctr = reader.ReadUInt64();
+            Ctr = reader.ReadBytes(8).Reverse().ToArray();
             reader.BaseStream.Position += 184;
         }
     }
@@ -280,4 +281,11 @@ namespace libhac
         Romfs,
         Bktr
     }
+
+    public enum Validity
+    {
+        Unchecked,
+        Invalid,
+        Valid
+    }
 }

libhac/SdFs.cs

@@ -62,7 +62,7 @@ namespace libhac
                 var title = new Title();
 
                 // Meta contents always have 1 Partition FS section with 1 file in it
-                Stream sect = nca.OpenSection(0);
+                Stream sect = nca.OpenSection(0, false);
                 var pfs0 = new Pfs0(sect);
                 var file = pfs0.GetFile(0);