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ClusterFuzz found a 32-bit PE file that triggers DCHECK(). The cause (in
DisassemblerWin32):
* ParseAndStoreRelocBlocks() reads malformed reloc region and rejects
it, but writes bad result to |reloc_region_| (with kInvalidOffset).
* MakeReadRelocs() passes the invalid |reloc_region_|, which causes
uint32_t overflow (for 32-bit size_t), and triggering DCHECK().
* MakeWriteRelocs() was not reached, but has similar problem.
Main fix:
* Initialize |reloc_region_| to invalid state.
* In ParseAndStoreRelocBlocks():
* On first run: Only write |reloc_region_| on success.
* On later runs: Return validity of |reloc_region_|.
* In MakeReadRelocs() and MakeWriteRelocs(): Already calls
ParseAndStoreRelocBlocks(). Change this to return vacuous
ReferenceReader / ReferenceWriter on failure, i.e., if
|reloc_region_| is invalid.
* Need to add EmptyReferenceWriter for this.
DisassemblerWin32 is also too lax in dealing with malformed input, so
this CL also implments more stringent checks:
* Disallow ImageSectionHeader (+ ImageOptionalHeader) from overlapping
with ImageDOSHeader.
* Apply more stringent checks for |size_of_optional_header| and
|number_of_rva_and_sizes|: Consistency and bounds.
Bug: 917042
Change-Id: I661303d49a57025a877585eb175f369d067652a4
Reviewed-on: https://chromium-review.googlesource.com/c/1390766
Reviewed-by: Samuel Huang <huangs@chromium.org>
Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619316}
NOKEYCHECK=True
GitOrigin-RevId: d46be686cb9e764befdd39aa168dde62b5314e37
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