On 10/22/18 5:30 AM, Kees Cook wrote:
> The arm compiler internally interprets an inline assembly label
> as an unsigned long value, not a pointer. As a result, under
> CONFIG_FORTIFY_SOURCE, the size of the array pointed to by an address
> of a label is 4 bytes, which was tripping the runtime checks. Instead,
> we can just cast the label (as done with the size calculations earlier)
> to avoid the problem.
>
> Reported-by: William Cohen <wco...@redhat.com>
> Fixes: 6974f0c4555e ("include/linux/string.h: add the option of fortified
> string.h functions")
> Cc: sta...@vger.kernel.org
> Signed-off-by: Kees Cook <keesc...@chromium.org>
> ---
> arch/arm/probes/kprobes/opt-arm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/probes/kprobes/opt-arm.c
> b/arch/arm/probes/kprobes/opt-arm.c
> index b2aa9b32bff2..2c118a6ab358 100644
> --- a/arch/arm/probes/kprobes/opt-arm.c
> +++ b/arch/arm/probes/kprobes/opt-arm.c
> @@ -247,7 +247,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe
> *op, struct kprobe *or
> }
>
> /* Copy arch-dep-instance from template. */
> - memcpy(code, &optprobe_template_entry,
> + memcpy(code, (unsigned char *)optprobe_template_entry,
> TMPL_END_IDX * sizeof(kprobe_opcode_t));
>
> /* Adjust buffer according to instruction. */
>
The patch fixes the issue for kretprobes. It looks good to me.
Thanks,
-Will
