ReadWin32Resources walked the PE resource directory tree with raw native pointer
arithmetic over attacker-controlled offsets, counts and sizes, with no bounds
checks, no recursion-depth limit and no cycle detection. The root section pointer
came from GetSectionData, whose length was read and then discarded, leaving every
dereference unbounded.
A crafted assembly could therefore turn merely opening it (the Save as project
feature reads these resources unconditionally) into an uncatchable process kill or
an out-of-bounds native read: a subdirectory entry pointing back at itself recursed
until the stack overflowed; an inflated entry count walked off the section end; and
a data entry whose Size was up to 4 GB made Buffer.MemoryCopy read far past the
section, faulting on an unmapped page or copying adjacent process memory into the
byte[] later written to app.ico/app.manifest on disk. None of this is containable,
since a StackOverflowException cannot be caught and the repo has no corrupted-state
exception handling. This is the sibling of the bundle signature fix in a154a7bbb.
Carry the section length alongside the root pointer and bounds-check every offset,
entry count, name-string length and data Size against it, cap recursion depth and
track visited directory offsets to break cycles. A hostile or truncated file now
yields a bounded, partial tree instead of a crash; well-formed resources parse
exactly as before. The parser no longer needs the whole PEReader, only a delegate
that resolves a data RVA to a bounded pointer, which is the seam the new tests drive
over a pinned buffer.
Assisted-by: Claude:claude-opus-4-8:Claude Code
On FIPS-mode systems the platform crypto provider refuses to create
SHA-1 instances (OpenSSL: error:03000098 invalid digest), so merely
displaying a strong-named assembly's identity failed. The public-key
token is a non-secret identity hash whose algorithm is fixed by
ECMA-335, so the two token sites now use dotnet/runtime's managed
Sha1ForNonSecretPurposes, vendored with its license header intact and
shielded from the repo formatter via generated_code in .editorconfig
so future upstream syncs diff cleanly. IncrementalHash was considered
and rejected: like SHA1.Create(), it resolves the digest through the
host crypto policy, and Roslyn's equivalent token code also relies on
the platform SHA-1, so it offers no precedent for FIPS safety.
Assisted-by: Claude:claude-fable-5:Claude Code
Compilation uses the .NET builds of the Roslyn toolsets (tasks/netcore*,
bincore csc.dll/vbc.dll launched through the dotnet host). ilasm/ildasm
options use the '-' prefix, which all platforms accept. The dotnet-hosted
compilers have no implicit references or SDK path: net40 compiles pass
mscorlib explicitly, and vbc gets -sdkpath, _MYTYPE=Empty and
-vbruntime:Microsoft.VisualBasic.Core.dll (the facade in the ref packs is
not followed for runtime helpers). The TestRunner gets a self-contained
build for the host platform.
Configurations depending on Windows-only tools or runtimes (legacy
csc/vbc, Roslyn 1.x/2.x, mcs, Force32Bit, executing net40 binaries) are
filtered from the matrix off-Windows via Tester.SupportedOnCurrentPlatform
or gated with [Platform("Win")]. PdbGen comparisons normalize document
name separators, and Correctness/Async uses Console.IsInputRedirected
instead of the Windows-only Console.CapsLock.
Assisted-by: Claude:claude-fable-5:Claude Code
Christoph Wille
Siegfried Pammer
Peter Crabtree
dotnet format
Daniel Grunwald
Kirill Osenkov