Skip to content

Fix CordbReJitILCode reading small-format EH sections and tiny headers #135920

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
max-charlamb merged 2 commits into from
Oct 29, 2026
Merged

Fix CordbReJitILCode reading small-format EH sections and tiny headers #135920

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
de5fb53
Fix CordbReJitILCode reading small EH sections
pcshrosbree Oct 16, 2026
04bda80
Skip EH sections after a tiny ReJIT IL header
pcshrosbree Oct 16, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
11 changes: 7 additions & 4 deletions src/coreclr/debug/di/module.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3304,8 +3304,9 @@ HRESULT CordbReJitILCode::Init(DacSharedReJitInfo* pSharedReJitInfo)
m_cbLocalIL = ilCodeSize;
IfFailRet(GetProcess()->SafeReadBuffer(m_codeRegionInfo, m_pLocalIL, FALSE /*throwOnError*/));

// Check if this il code has exception clauses
if ((pMethodTinyHeader->Flags_CodeSize & CorILMethod_MoreSects) == 0)
// Check if this il code has exception clauses. A tiny header has no flags for extra sections:
// its upper bits are the code size, so CorILMethod_MoreSects only applies to a fat header.
if (isTinyHeader || (pMethodTinyHeader->Flags_CodeSize & CorILMethod_MoreSects) == 0)
{
return S_OK; // no EH, done initing
}
Expand Down Expand Up @@ -3358,14 +3359,16 @@ HRESULT CordbReJitILCode::Init(DacSharedReJitInfo* pSharedReJitInfo)
// Read in the section header to see how many small clauses there are
IMAGE_COR_ILMETHOD_SECT_SMALL sectionHeader = { 0 };
IfFailRet(GetProcess()->SafeReadStruct(ehClauseHeader, &sectionHeader));
ULONG32 m_cClauses = (sectionHeader.DataSize - 4) / sizeof(IMAGE_COR_ILMETHOD_SECT_SMALL);
// The small clauses start after the 2 byte section header and a 2 byte Reserved field
const ULONG32 cbSmallSectionHeader = offsetof(IMAGE_COR_ILMETHOD_SECT_EH_SMALL, Clauses);
m_cClauses = (sectionHeader.DataSize - cbSmallSectionHeader) / sizeof(IMAGE_COR_ILMETHOD_SECT_EH_CLAUSE_SMALL);
if (m_cClauses > 10000) // sanity check the data before allocating
{
return CORDBG_E_TARGET_INCONSISTENT;
}

// Read in the clauses
TargetBuffer buffer(ehClauseHeader + sizeof(IMAGE_COR_ILMETHOD_SECT_SMALL), m_cClauses*sizeof(IMAGE_COR_ILMETHOD_SECT_EH_CLAUSE_SMALL));
TargetBuffer buffer(ehClauseHeader + cbSmallSectionHeader, m_cClauses*sizeof(IMAGE_COR_ILMETHOD_SECT_EH_CLAUSE_SMALL));
NewArrayHolder<IMAGE_COR_ILMETHOD_SECT_EH_CLAUSE_SMALL> pClauses = new (nothrow)IMAGE_COR_ILMETHOD_SECT_EH_CLAUSE_SMALL[m_cClauses];
if (pClauses == NULL)
return E_OUTOFMEMORY;
Expand Down
Loading