[release/10.0] Fix IJW OverflowException with 17+ by-ref parameters#127342
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JulieLeeMSFT merged 6 commits intorelease/10.0from Apr 24, 2026
Merged
[release/10.0] Fix IJW OverflowException with 17+ by-ref parameters#127342JulieLeeMSFT merged 6 commits intorelease/10.0from
JulieLeeMSFT merged 6 commits intorelease/10.0from
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StubSigBuilder::EnsureEnoughQuickBytes only doubled the buffer size once, so when the required size exceeded 2x the current buffer, the CQuickBytes inline buffer (512 bytes) overflowed into the adjacent m_nItems field. This was triggered by PR #106000 which changed ConvertToInternalSignature to preserve custom modifiers (bSkipCustomModifier=FALSE). Each preserved modifier adds 10 bytes (ELEMENT_TYPE_CMOD_INTERNAL + required byte + 8-byte TypeHandle pointer) to the signature. For 18+ parameters with custom modifiers, the total signature exceeded 512 bytes, causing a buffer overflow that corrupted m_nItems and led to an OverflowException. The fix loops the doubling until the buffer is large enough. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- Use S_SIZE_T for checked arithmetic in EnsureEnoughQuickBytes to prevent infinite loop or undersized allocation on SIZE_T overflow. - Remove unnecessary NativeSum18ByRefEntryPoint DLL export. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
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AaronRobinsonMSFT
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Apr 23, 2026
JulieLeeMSFT
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Backport of #127182 to release/10.0
/cc @jkoritzinsky
Customer Impact
Calls from native code to managed in C++/CLI with 17 byref parameters crashes the process. #127166
This PR fixes the underlying buffer management issue that causes the problem
Regression
#106000
Testing
Unit tests were added.
Risk
Low, only hit with extremely long signatures and we have testing guarding this scenario now.
IMPORTANT: If this backport is for a servicing release, please verify that:
release/X.0-staging, notrelease/X.0.release/X.0(no-stagingsuffix).Package authoring no longer needed in .NET 9
IMPORTANT: Starting with .NET 9, you no longer need to edit a NuGet package's csproj to enable building and bump the version.
Keep in mind that we still need package authoring in .NET 8 and older versions.