Messages in this thread | | | From | Justin Stitt <> | Date | Tue, 3 Oct 2023 16:06:28 -0700 | Subject | Re: [PATCH 5/5] mlxsw: spectrum_span: Annotate struct mlxsw_sp_span with __counted_by |
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On Fri, Sep 29, 2023 at 11:08 AM Kees Cook <keescook@chromium.org> wrote: > > Prepare for the coming implementation by GCC and Clang of the __counted_by > attribute. Flexible array members annotated with __counted_by can have > their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS > (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family > functions). > > As found with Coccinelle[1], add __counted_by for struct mlxsw_sp_span. > > [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci > > Cc: Ido Schimmel <idosch@nvidia.com> > Cc: Petr Machata <petrm@nvidia.com> > Cc: "David S. Miller" <davem@davemloft.net> > Cc: Eric Dumazet <edumazet@google.com> > Cc: Jakub Kicinski <kuba@kernel.org> > Cc: Paolo Abeni <pabeni@redhat.com> > Cc: netdev@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> > ---
Great patch!
Crucially, span->entries_count is assigned before any flexible array accesses.
span->entries_count = entries_count; ... for (i = 0; i < mlxsw_sp->span->entries_count; i++) mlxsw_sp->span->entries[i].id = i;
Reviewed-by: Justin Stitt <justinstitt@google.com>
> drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c > index b3472fb94617..af50ff9e5f26 100644 > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c > @@ -31,7 +31,7 @@ struct mlxsw_sp_span { > refcount_t policer_id_base_ref_count; > atomic_t active_entries_count; > int entries_count; > - struct mlxsw_sp_span_entry entries[]; > + struct mlxsw_sp_span_entry entries[] __counted_by(entries_count); > }; > > struct mlxsw_sp_span_analyzed_port { > -- > 2.34.1 > > Thanks Justin
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