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Date:   Fri, 15 Sep 2023 13:25:36 -0600
From:   "Gustavo A. R. Silva" <gustavoars@kernel.org>
To:     Ishizaki Kou <kou.ishizaki@toshiba.co.jp>,
        Geoff Levand <geoff@infradead.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc:     netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-kernel@vger.kernel.org,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        linux-hardening@vger.kernel.org
Subject: [PATCH][next] net: spider_net: Use size_add() in call to
 struct_size()
Message-ID: <ZQSvsLmJrDsKtLCa@work>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Precedence: bulk

If, for any reason, the open-coded arithmetic causes a wraparound,
the protection that `struct_size()` adds against potential integer
overflows is defeated. Fix this by hardening call to `struct_size()`
with `size_add()`.

Fixes: 3f1071ec39f7 ("net: spider_net: Use struct_size() helper")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/net/ethernet/toshiba/spider_net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/toshiba/spider_net.c b/drivers/net/ethernet/toshiba/spider_net.c
index 50d7eacfec58..87e67121477c 100644
--- a/drivers/net/ethernet/toshiba/spider_net.c
+++ b/drivers/net/ethernet/toshiba/spider_net.c
@@ -2332,7 +2332,7 @@ spider_net_alloc_card(void)
 	struct spider_net_card *card;
 
 	netdev = alloc_etherdev(struct_size(card, darray,
-					    tx_descriptors + rx_descriptors));
+					    size_add(tx_descriptors, rx_descriptors)));
 	if (!netdev)
 		return NULL;
 
-- 
2.34.1