Check crc on tar header

StarkDirewolf · Jul 10, 2024 · e42d953 · e42d953
1 parent d18cad6
commit e42d953
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Showing 3 changed files with 16 additions and 2 deletions.
diff --git a/src/SharpCompress/Common/Tar/Headers/TarHeader.cs b/src/SharpCompress/Common/Tar/Headers/TarHeader.cs
@@ -134,6 +134,13 @@ internal bool Read(BinaryReader reader)
             hasLongValue = false;
         } while (hasLongValue);
 
+        var crc = ReadAsciiInt64Base8(buffer, 148, 7);
+
+        if (crc != RecalculateChecksum(buffer))
+        {
+            return false;
+        }
+
         Name = longName ?? ArchiveEncoding.Decode(buffer, 0, 100).TrimNulls();
         EntryType = entryType;
         Size = ReadSize(buffer);

diff --git a/tests/SharpCompress.Test/Tar/TarArchiveTests.cs b/tests/SharpCompress.Test/Tar/TarArchiveTests.cs
@@ -217,8 +217,7 @@ public void Tar_Empty_Archive()
     {
         var archiveFullPath = Path.Combine(TEST_ARCHIVES_PATH, "Tar.Empty.tar");
         using Stream stream = File.OpenRead(archiveFullPath);
-        using var archive = ArchiveFactory.Open(stream);
-        Assert.True(archive.Type == ArchiveType.Tar);
+        Assert.Throws<InvalidOperationException>(() => ArchiveFactory.Open(stream));
     }
 
     [Theory]
@@ -287,4 +286,12 @@ public void Tar_Read_One_At_A_Time()
 
         Assert.Equal(2, numberOfEntries);
     }
+
+    [Fact]
+    public void Tar_Detect_Test()
+    {
+        var isTar = TarArchive.IsTarFile(Path.Combine(TEST_ARCHIVES_PATH, "false.positive.tar"));
+
+        Assert.False(isTar);
+    }
 }
diff --git a/tests/TestArchives/Archives/false.positive.tar b/tests/TestArchives/Archives/false.positive.tar