Re: [PATCH v3 09/17] treewide: Change list_sort to use const pointers

From: Kees Cook
Date: Fri Mar 26 2021 - 00:36:19 EST


On Tue, Mar 23, 2021 at 01:39:38PM -0700, Sami Tolvanen wrote:
> list_sort() internally casts the comparison function passed to it
> to a different type with constant struct list_head pointers, and
> uses this pointer to call the functions, which trips indirect call
> Control-Flow Integrity (CFI) checking.
>
> Instead of removing the consts, this change defines the
> list_cmp_func_t type and changes the comparison function types of
> all list_sort() callers to use const pointers, thus avoiding type
> mismatches.
>
> Suggested-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

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Kees Cook