ffi: avoid memcpy() with a null pointer - #66200
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christianaurichzm wants to merge 1 commit into
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Zero-length FFI memory operations accept a null pointer, but ToArrayBuffer() and ExportBytes() call memcpy() unconditionally. Passing a null pointer to memcpy() is undefined behavior even when the size is zero. Skip the copy when the length is zero, matching what Buffer::Copy() already does for the same case. An isolated reproduction compiled with -fsanitize=undefined reports "null pointer passed as argument 1, which is declared to never be null". The added test covers the reachable zero-length paths, but it passes without the fix: libc does not fault on memcpy(NULL, NULL, 0), and --enable-ubsan does not set -fno-sanitize-recover, so UBSan reports the call without failing the process. Signed-off-by: Christian Aurich Zanettini Martins <christian.aurichzm@gmail.com>
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #66200 +/- ##
==========================================
- Coverage 90.29% 90.27% -0.02%
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Files 790 790
Lines 272529 272531 +2
Branches 52037 52034 -3
==========================================
- Hits 246074 246037 -37
- Misses 16908 16954 +46
+ Partials 9547 9540 -7
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ToArrayBuffer()andExportBytes()accept zero-length operations with a nullpointer, but still call
memcpy(). Passing a null pointer tomemcpy()isundefined behavior even when the size is zero.
Skip the copy when the length is zero, matching
Buffer::Copy().Tests cover the zero-length FFI memory entry points. Full configured test suite,
C++ lint/format, and ESLint pass.