David Benjamin bde4ffe752 Don't pass null pointers to memcmp and memcpy in libFuzzer (#96775) ...

In C, it is UB to call `memcmp(NULL, NULL, 0)`, `memcpy(NULL, NULL, 0)`,
etc. Unfortunately, `(NULL, 0)` is the natural representation of an
empty sequence of objects and extremely common in real world code. As a
result, all C code, and C++ code which calls into C functions, must
carefully guard all calls to `memcpy`.

This is a serious, real world usability issue in C and should be fixed
in the language (see #49459). In the meantime, pay the cost of the extra
branch to avoid tripping UBSan in libFuzzer. Once the usability problem
in C has been fixed, these checks can be removed.

Fixes #96772

2024-08-13 15:26:40 -07:00

32 KiB

Raw Blame History

View Raw