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From:   Wong Vee Khee <vee.khee.wong@linux.intel.com>
To:     Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc:     netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH net-next v1 1/1] net: stmmac: Fix potential integer overflow
Date:   Fri, 11 Jun 2021 17:02:38 +0800
Message-Id: <20210611090238.1157557-1-vee.khee.wong@linux.intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The commit d96febedfde2 ("net: stmmac: arrange Tx tail pointer update
to stmmac_flush_tx_descriptors") introduced the following coverity
warning:-

  1. Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN)
     overflow_before_widen: Potentially overflowing expression
     'tx_q->cur_tx * desc_size' with type 'unsigned int' (32 bits,
     unsigned) is evaluated using 32-bit arithmetic, and then used in a
     context that expects an expression of type dma_addr_t (64 bits,
     unsigned).

Fixed this by assigning tx_tail_addr to dma_addr_t type, as dma_addr_t
datatype is decided by CONFIG_ARCH_DMA_ADDR_T_64_BIT.

Fixes: d96febedfde2 ("net: stmmac: arrange Tx tail pointer update to stmmac_flush_tx_descriptors")
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index fd7212afc543..6655cb8e24cf 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -75,7 +75,7 @@ struct stmmac_tx_queue {
 	unsigned int cur_tx;
 	unsigned int dirty_tx;
 	dma_addr_t dma_tx_phy;
-	u32 tx_tail_addr;
+	dma_addr_t tx_tail_addr;
 	u32 mss;
 };
 
-- 
2.25.1