Skip to content

[release/10.0] Fix IJW OverflowException with 17+ by-ref parameters#127342

Open
github-actions[bot] wants to merge 6 commits intorelease/10.0from
backport/pr-127182-to-release/10.0
Open

[release/10.0] Fix IJW OverflowException with 17+ by-ref parameters#127342
github-actions[bot] wants to merge 6 commits intorelease/10.0from
backport/pr-127182-to-release/10.0

Conversation

@github-actions
Copy link
Copy Markdown
Contributor

Backport of #127182 to release/10.0

/cc @jkoritzinsky

Customer Impact

  • Customer reported
  • Found internally

[Select one or both of the boxes. Describe how this issue impacts customers, citing the expected and actual behaviors and scope of the issue. If customer-reported, provide the issue number.]

Regression

  • Yes
  • No

[If yes, specify when the regression was introduced. Provide the PR or commit if known.]

Testing

[How was the fix verified? How was the issue missed previously? What tests were added?]

Risk

[High/Medium/Low. Justify the indication by mentioning how risks were measured and addressed.]

IMPORTANT: If this backport is for a servicing release, please verify that:

  • For .NET 8 and .NET 9: The PR target branch is release/X.0-staging, not release/X.0.
  • For .NET 10+: The PR target branch is release/X.0 (no -staging suffix).

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.

jkoritzinsky and others added 6 commits April 23, 2026 20:31
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>
@dotnet-policy-service
Copy link
Copy Markdown
Contributor

Tagging subscribers to this area: @dotnet/interop-contrib
See info in area-owners.md if you want to be subscribed.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants