Re: linux-next: build failure after merge of the kspp tree

Kees Cook
2022-01-31T04:04:04Z

On Mon, Jan 31, 2022 at 10:09:54AM +1100, Stephen Rothwell wrote:
> Hi all,
>
> After merging the kspp tree, today's linux-next build (x86_64
> allmodconfig) failed like this:
>
> In file included from include/linux/string.h:253,
> from include/linux/bitmap.h:11,
> from include/linux/cpumask.h:12,
> from arch/x86/include/asm/cpumask.h:5,
> from arch/x86/include/asm/msr.h:11,
> from arch/x86/include/asm/processor.h:22,
> from arch/x86/include/asm/timex.h:5,
> from include/linux/timex.h:65,
> from include/linux/time32.h:13,
> from include/linux/time.h:60,
> from include/linux/skbuff.h:15,
> from include/linux/tcp.h:17,
> from drivers/net/ethernet/mellanox/mlx5/core/en_tx.c:33:
> In function 'fortify_memcpy_chk',
> inlined from 'mlx5e_insert_vlan' at drivers/net/ethernet/mellanox/mlx5/core/en_tx.c:211:2,
> inlined from 'mlx5e_sq_xmit_wqe' at drivers/net/ethernet/mellanox/mlx5/core/en_tx.c:496:4:
> include/linux/fortify-string.h:325:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
> 325 | __write_overflow_field(p_size_field, size);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This should be fixed by:
https://lore.kernel.org/linux-hardening/20220124172242.2410996-1-keescook@chromium.org/
(I was expecting this to be in netdev by now.)

> In file included from include/linux/string.h:253,
> from include/linux/bitmap.h:11,
> from include/linux/cpumask.h:12,
> from arch/x86/include/asm/cpumask.h:5,
> from arch/x86/include/asm/msr.h:11,
> from arch/x86/include/asm/processor.h:22,
> from arch/x86/include/asm/timex.h:5,
> from include/linux/timex.h:65,
> from include/linux/time32.h:13,
> from include/linux/time.h:60,
> from include/linux/ktime.h:24,
> from include/linux/timer.h:6,
> from include/linux/netdevice.h:24,
> from include/trace/events/xdp.h:8,
> from include/linux/bpf_trace.h:5,
> from drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c:33:
> In function 'fortify_memcpy_chk',
> inlined from 'mlx5e_xmit_xdp_frame' at drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c:344:3:
> include/linux/fortify-string.h:325:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
> 325 | __write_overflow_field(p_size_field, size);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This should be fixed in:
https://lore.kernel.org/linux-hardening/20220124172028.2410761-1-keescook@chromium.org/
(Again, this was expected to be in netdev by now.)

> Caused by various commits in the mlx5 driver interacting with the new
> memcpy checking.
>
> I have disabled CONFIG_MLX5_CORE_EN for today while this gets sorted
> out properly.

Thanks!

-Kees

--
Kees Cook