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From:   Kees Cook <keescook@chromium.org>
To:     Ido Schimmel <idosch@nvidia.com>
Cc:     Kees Cook <keescook@chromium.org>, Petr Machata <petrm@nvidia.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org, llvm@lists.linux.dev
Subject: [PATCH 1/5] mlxsw: Annotate struct mlxsw_linecards with __counted_by
Date:   Fri, 29 Sep 2023 11:07:40 -0700
Message-Id: <20230929180746.3005922-1-keescook@chromium.org>
In-Reply-To: <20230929180611.work.870-kees@kernel.org>
References: <20230929180611.work.870-kees@kernel.org>
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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_linecards.

[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>
---
 drivers/net/ethernet/mellanox/mlxsw/core.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.h b/drivers/net/ethernet/mellanox/mlxsw/core.h
index e5474d3e34db..c6bc5819ce43 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.h
@@ -624,7 +624,7 @@ struct mlxsw_linecards {
 	struct mlxsw_linecard_types_info *types_info;
 	struct list_head event_ops_list;
 	struct mutex event_ops_list_lock; /* Locks accesses to event ops list */
-	struct mlxsw_linecard linecards[];
+	struct mlxsw_linecard linecards[] __counted_by(count);
 };
 
 static inline struct mlxsw_linecard *
-- 
2.34.1