On 06/25/2019 06:41 PM, Jiong Wang wrote:
> Yauheni reported the following code do not work correctly on BE arches:
>
> ALU_ARSH_X:
> DST = (u64) (u32) ((*(s32 *) &DST) >> SRC);
> CONT;
> ALU_ARSH_K:
> DST = (u64) (u32) ((*(s32 *) &DST) >> IMM);
> CONT;
>
> and are causing failure of test_verifier test 'arsh32 on imm 2' on BE
> arches.
>
> The code is taking address and interpreting memory directly, so is not
> endianness neutral. We should instead perform standard C type casting on
> the variable. A u64 to s32 conversion will drop the high 32-bit and reserve
> the low 32-bit as signed integer, this is all we want.
>
> Fixes: 2dc6b100f928 ("bpf: interpreter support BPF_ALU | BPF_ARSH")
> Reported-by: Yauheni Kaliuta <yauheni.kaliuta@xxxxxxxxxx>
> Reviewed-by: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>
> Reviewed-by: Quentin Monnet <quentin.monnet@xxxxxxxxxxxxx>
> Signed-off-by: Jiong Wang <jiong.wang@xxxxxxxxxxxxx>
Applied, thanks!
