Since the SLAB allocator has been removed, so we can clean up the
sl[au]b_$params. With only one slab allocator left, it's better to use the
generic "slab" term instead of "slub" which is an implementation detail,
which is pointed out by Vlastimil Babka. For more information please see
[1]. Hence, we are going to use "slab_$param" as the primary prefix.
This patch is changing the following slab parameters
- slub_max_order
- slub_min_order
- slub_min_objects
- slub_debug
to
- slab_max_order
- slab_min_order
- slab_min_objects
- slab_debug
as the primary slab parameters for all references of them in docs and
comments. But this patch won't change variables and functions inside
slub as we will have wider slub/slab change.
Meanwhile, "slub_$params" can also be passed by command line, which is
to keep backward compatibility. Also mark all "slub_$params" as legacy.
Remove the separate descriptions for slub_[no]merge, append legacy tip
for them at the end of descriptions of slab_[no]merge.
[1] https://lore.kernel.org/linux-mm/7512b350-4317-21a0-fab3-4101bc4d8f7a@suse.cz/
Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Since the commits starting with c37495d625 ("slab: add __alloc_size
attributes for better bounds checking"), the compilers have runtime
allocation size hints available in some places. This was immediately
available to CONFIG_UBSAN_BOUNDS, but CONFIG_FORTIFY_SOURCE needed
updating to explicitly make use of the hints via the associated
__builtin_dynamic_object_size() helper. Detect and use the builtin when
it is available, increasing the accuracy of the mitigation. When runtime
sizes are not available, __builtin_dynamic_object_size() falls back to
__builtin_object_size(), leaving the existing bounds checking unchanged.
Additionally update the VMALLOC_LINEAR_OVERFLOW LKDTM test to make the
hint invisible, otherwise the architectural defense is not exercised
(the buffer overflow is detected in the memset() rather than when it
crosses the edge of the allocation).
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Tom Rix <trix@redhat.com>
Cc: linux-hardening@vger.kernel.org
Cc: llvm@lists.linux.dev
Reviewed-by: Miguel Ojeda <ojeda@kernel.org> # include/linux/compiler_attributes.h
Signed-off-by: Kees Cook <keescook@chromium.org>
With the kmalloc() size annotations, GCC is smart enough to realize that
LKDTM is intentionally writing past the end of the buffer. This is on
purpose, of course, so hide the buffer from the optimizer. Silences:
../drivers/misc/lkdtm/heap.c: In function 'lkdtm_SLAB_LINEAR_OVERFLOW':
../drivers/misc/lkdtm/heap.c:59:13: warning: array subscript 256 is outside array bounds of 'void[1020]' [-Warray-bounds]
59 | data[1024 / sizeof(u32)] = 0x12345678;
| ~~~~^~~~~~~~~~~~~~~~~~~~
In file included from ../drivers/misc/lkdtm/heap.c:7:
In function 'kmalloc',
inlined from 'lkdtm_SLAB_LINEAR_OVERFLOW' at ../drivers/misc/lkdtm/heap.c:54:14:
../include/linux/slab.h:581:24: note: at offset 1024 into object of size 1020 allocated by 'kmem_cache_alloc_trace'
581 | return kmem_cache_alloc_trace(
| ^~~~~~~~~~~~~~~~~~~~~~~
582 | kmalloc_caches[kmalloc_type(flags)][index],
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
583 | flags, size);
| ~~~~~~~~~~~~
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
It's long been annoying that to add a new LKDTM test one had to update
lkdtm.h and core.c to get it "registered". Switch to a per-category
list and update the crashtype walking code in core.c to handle it.
This also means that all the lkdtm_* tests themselves can be static now.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
The LKDTM modules keep expanding, and it's getting weird to have each file
get a prefix. Instead, move to a subdirectory for cleaner handling.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
