[all-commits] [llvm/llvm-project] a3a436: [ASAN] Fix validation size for dirent on FreeBSD

[Justin Cady via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a3a4369ea100d8693d45dc21eda9c2c8171b1068
      https://github.com/llvm/llvm-project/commit/a3a4369ea100d8693d45dc21eda9c2c8171b1068
  Author: Justin Cady <desk at justincady.com>
  Date:   2023-06-07 (Wed, 07 Jun 2023)

  Changed paths:
    M compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
    M compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.cpp
    M compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.h
    M compiler-rt/lib/sanitizer_common/sanitizer_posix.h
    A compiler-rt/test/sanitizer_common/TestCases/scandir.c

  Log Message:
  -----------
  [ASAN] Fix validation size for dirent on FreeBSD

Typically the size required to represent a dirent is stored in `d_reclen`. But
this not always the case for FreeBSD (for example, when walking a directory
over NFS).

This leads to ASAN false positives for `scandir` and similar functions. Because
ASAN uses `d_reclen` for the range to validate, it can overrun when `d_reclen` is
incorrect (too large).

This change adds `__sanitizer_dirsiz` which fixes the dirent size calculation
for FreeBSD. Other platforms continue to use `d_reclen`.

Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D151583