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    Subject[PATCH 12/12] slab: Restore __alloc_size attribute to __kmalloc_track_caller
    Date
    With skbuff's post-allocation use of ksize() rearranged to use
    kmalloc_size_round() prior to allocation, the compiler can correctly
    reason about the size of these allocations. The prior mismatch had caused
    buffer overflow mitigations to erroneously fire under CONFIG_UBSAN_BOUNDS,
    requiring a partial revert of the __alloc_size attributes. Restore the
    attribute that had been removed in commit 93dd04ab0b2b ("slab: remove
    __alloc_size attribute from __kmalloc_track_caller").

    Cc: Pekka Enberg <penberg@kernel.org>
    Cc: David Rientjes <rientjes@google.com>
    Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: linux-mm@kvack.org
    Signed-off-by: Kees Cook <keescook@chromium.org>
    ---
    include/linux/slab.h | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    diff --git a/include/linux/slab.h b/include/linux/slab.h
    index ac3832b50dbb..dd50ed7207c9 100644
    --- a/include/linux/slab.h
    +++ b/include/linux/slab.h
    @@ -693,7 +693,8 @@ static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flag
    * allocator where we care about the real place the memory allocation
    * request comes from.
    */
    -extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller);
    +extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
    + __alloc_size(1);
    #define kmalloc_track_caller(size, flags) \
    __kmalloc_track_caller(size, flags, _RET_IP_)

    --
    2.34.1
    \
     
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