On August 18, 2021 9:05 AM -0300, Kees Cook wrote:
> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> field bounds checking for memset(), avoid intentionally writing across
> neighboring fields.
>
> Use memset_startat() so memset() doesn't get confused about writing
> beyond the destination member that is intended to be the starting point
> of zeroing through the end of the struct.
>
> The old code was doing the wrong thing: it starts from the second member
> and writes beyond int_info, clobbering qede_lock:
>
> struct qede_dev {
> ...
> struct qed_int_info int_info;
>
> /* Smaller private variant of the RTNL lock */
> struct mutex qede_lock;
> ...
>
> struct qed_int_info {
> struct msix_entry *msix;
> u8 msix_cnt;
>
> /* This should be updated by the protocol driver */
> u8 used_cnt;
> };
>
> Cc: Ariel Elior <aelior@xxxxxxxxxxx>
> Cc: GR-everest-linux-l2@xxxxxxxxxxx
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
> drivers/net/ethernet/qlogic/qede/qede_main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/qlogic/qede/qede_main.c
> b/drivers/net/ethernet/qlogic/qede/qede_main.c
> index d400e9b235bf..0ed9a0c8452c 100644
> --- a/drivers/net/ethernet/qlogic/qede/qede_main.c
> +++ b/drivers/net/ethernet/qlogic/qede/qede_main.c
> @@ -2419,7 +2419,7 @@ static int qede_load(struct qede_dev *edev, enum
> qede_load_mode mode,
> goto out;
> err4:
> qede_sync_free_irqs(edev);
> - memset(&edev->int_info.msix_cnt, 0, sizeof(struct qed_int_info));
> + memset_startat(&edev->int_info, 0, msix_cnt);
As I commented on V1:
"[PATCH 42/64] net: qede: Use memset_after() for counters",
the memset is redundant and it should clear only the msix_cnt.
We will fix it.
> err3:
> qede_napi_disable_remove(edev);
> err2:
> --
> 2.30.2
