Merge pull request #24 from jogibear9988/main

fix: correct truncated legacy fingerprint lookup table

Author: bonk-dev

Directory.Build.props

@@ -11,11 +11,11 @@
         <RepositoryType>git</RepositoryType>
         <PackageTags>siemens;s7</PackageTags>
 
-        <PackageVersion>1.1.2</PackageVersion>
-        <AssemblyVersion>1.1.2</AssemblyVersion>
-        <FileVersion>1.1.2</FileVersion>
-        <Version>1.1.2</Version>
-        <PackageReleaseNotes>Internal naming changes</PackageReleaseNotes>
+        <PackageVersion>1.1.3</PackageVersion>
+        <AssemblyVersion>1.1.3</AssemblyVersion>
+        <FileVersion>1.1.3</FileVersion>
+        <Version>1.1.3</Version>
+        <PackageReleaseNotes>Fix legacy challenge fingerprint derivation for the final lookup-table block.</PackageReleaseNotes>
 
         <PackageIcon>nuget-icon.png</PackageIcon>
     </PropertyGroup>

HarpoS7.Tests/Fingerprint/HarpoFingerprintTests.cs

@@ -5,6 +5,32 @@ namespace HarpoS7.Tests.Fingerprint;
 
 public class HarpoFingerprintTests
 {
+    [Test]
+    public void LookupTablesCoverEveryComputedBlock()
+    {
+        for (var index = 0; index < FingerprintConsts.Data1Collection.Length; index++)
+        {
+            var operations = FingerprintConsts.Data1Collection[index].Length / 3;
+            var requiredBytes = operations * 128;
+            var availableBytes = FingerprintConsts.Data2Collection[index].Length * sizeof(ushort);
+            Assert.That(
+                availableBytes,
+                Is.GreaterThanOrEqualTo(requiredBytes),
+                $"Fingerprint table {index} is too short for its computed indices");
+        }
+    }
+
+    [Test]
+    public void FingerprintChallengeHandlesCapturedLegacyRenewalEdgeCase()
+    {
+        Span<byte> fingerprint = stackalloc byte[FingerprintConsts.FingerprintLength];
+        var challenge = Convert.FromHexString("5B15B4694FC38A775E6778F0770C6E7A3118200D");
+
+        HarpoFingerprint.FingerprintChallenge(fingerprint, challenge);
+
+        Assert.That(Convert.ToHexString(fingerprint), Is.EqualTo("6AB5811DE6D28746"));
+    }
+
     public static IEnumerable<TestCaseData> FingerprintSubProcedureCases
         {
             get
@@ -1003,4 +1029,4 @@ public void FingerprintChallenge()
         var expectedFingerprint = new byte[8] { 0xe2, 0x87, 0xc1, 0xcb, 0x65, 0x9b, 0x9e, 0xdf }.AsSpan();
         Assert.That(expectedFingerprint.SequenceEqual(fingerprint));
     }
-}
+}

HarpoS7/Fingerprint/FingerprintConsts.cs

@@ -524,7 +524,7 @@ public static class FingerprintConsts
             0xd7b1, 0xe73f, 0x7a90, 0xb821, 0xc54b, 0xabd6, 0x7552, 0x4a40, 0xf0d3, 0x2dbf, 0x1fc5, 0xcc99, 0x8111,
             0x4305, 0x7080, 0xe835, 0xbf4, 0x43f, 0x6a5f, 0x2ab3, 0xf854, 0x1f7f, 0x3491, 0xd376, 0xd0bb, 0x7bc7,
             0xed86, 0x7fbc, 0x2e5b, 0xc137, 0x8bcb, 0xe9ad, 0xb41c, 0xd4ce, 0x77d5, 0xc22f, 0x929f, 0xb6b2, 0xd74f,
-            0xe11d, 0xf565, 0x823f, 0x518b, 0xa857, 0xbf08
+            0xe11d, 0xf565, 0x823f, 0x518b, 0xa857, 0xbf08, 0x4c28
         },
         new ushort[]
         {
@@ -2710,4 +2710,4 @@ public static class FingerprintConsts
             0xbc27, 0xf54d, 0x261
         },
     };
-}
+}