[v2,0/2] slab: Provide full coverage for __alloc_size attribute

Message

Kees Cook Nov. 18, 2022, 3:51 a.m. UTC

Hi,

These patches work around a deficiency in GCC (>=11) and Clang (<16)
where the __alloc_size attribute does not apply to inlines. :(
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503

This manifests as reduced overflow detection coverage for many allocation
sites under CONFIG_FORTIFY_SOURCE=y, where the allocation size was not
actually being propagated to __builtin_dynamic_object_size(). The problem
was in two halves: the trace wrapper (now fixed in -next), and const-0
special-casing (covered here).

Thanks,

-Kees

v2:
- drop trace wrapper refactoring -- handled differently now (vbabka)
- drop kunit/fortify test patch since it depends on other changes
- rebase
v1: https://lore.kernel.org/all/[e-mail]

Kees Cook (2):
  slab: Clean up SLOB vs kmalloc() definition
  slab: Remove special-casing of const 0 size allocations

 include/linux/slab.h | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)