Fix Int32 overflow bug in buffering logic #60459
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Tagging subscribers to this area: @dotnet/area-system-io |
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/backport to release/6.0 |
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Started backporting to release/6.0: https://github.com/dotnet/runtime/actions/runs/1345172097 |
Co-authored-by: Carlos Sanchez <[email protected]>
jozkee
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jozkee
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Found only nits, I also tried to see if I could find more overflow issues in BufferedFileStreamStrategy but didn't see any.
Thanks, @adamsitnik.
| using (var stream = new FileStream(filePath, FileMode.Create, FileAccess.Write)) | ||
| { | ||
| stream.Seek(position1, SeekOrigin.Begin); | ||
| stream.Write(data1, 0, data1.Length); |
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nit: Use Span-based overloads
| stream.Write(data1, 0, data1.Length); | |
| stream.Write(data1); |
| stream.Write(data1, 0, data1.Length); | ||
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| stream.Seek(position2, SeekOrigin.Begin); | ||
| stream.Write(data2, 0, data2.Length); |
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ditto
| stream.Write(data2, 0, data2.Length); | |
| stream.Write(data2); |
| using (var stream = new BufferedStream(new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.None, bufferSize: 0))) | ||
| { | ||
| stream.Seek(position1, SeekOrigin.Begin); | ||
| Assert.Equal(buffer.Length, stream.Read(buffer)); | ||
| Assert.Equal(data1, buffer); | ||
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| stream.Seek(position2, SeekOrigin.Begin); | ||
| Assert.Equal(buffer.Length, stream.Read(buffer)); | ||
| Assert.Equal(data2, buffer); | ||
| } |
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I think this piece of code should be a separate test in src/libraries/System.IO/tests/BufferedStream/BufferedStreamTests.cs
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Merging to keep the backport PR as a clean port of this one i.e: to not have different commits. CI issue |
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fixes #60430
For the following code:
For a
newPos > 4GBand smalloldPosand_readPoswe had an int32 overflow. Sample C# app to demonstrate the problem:It seems to be a very old bug that was always present in
BufferedStreamand I've copied it toBufferedFileStreamStrategyin 6.0.1.0 branch:
https://github.com/dotnet/corefx/blob/c74ea81f2ddad07dc05d695d8244fb2ece7e398d/src/System.IO/src/System/IO/BufferedStream.cs#L1053-L1054
Since we are very close to 6.0 release I've focused on making smallest possible change instead of doing a refactor and providing code that would look better but would be harder to review.