[PATCH 3/5] spi: spi-zynqmp-gqspi: Resolved slab-out-of-bounds bug

From: quanyang.wang@windriver.com
To: Mark Brown <broonie@kernel.org>,
	Michal Simek <michal.simek@xilinx.com>,
	Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>
Cc: linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Quanyang Wang <quanyang.wang@windriver.com>
Subject: [PATCH 3/5] spi: spi-zynqmp-gqspi: Resolved slab-out-of-bounds bug
Date: Fri, 16 Apr 2021 08:46:50 +0800	[thread overview]
Message-ID: <20210416004652.2975446-4-quanyang.wang@windriver.com> (raw)
In-Reply-To: <20210416004652.2975446-1-quanyang.wang@windriver.com>

From: Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>

During a transfer the driver filled the fifo with 4bytes,
even if the data that needs to be transfer is less that 4bytes.
This resulted in slab-out-of-bounds bug in KernelAddressSanitizer.

This patch resolves slab-out-of-bounds bug by filling the fifo
with the number of bytes that needs to transferred.

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>
---
 drivers/spi/spi-zynqmp-gqspi.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
index 1146359528b9..2e2607b5dee9 100644
--- a/drivers/spi/spi-zynqmp-gqspi.c
+++ b/drivers/spi/spi-zynqmp-gqspi.c
@@ -509,17 +509,19 @@ static void zynqmp_qspi_filltxfifo(struct zynqmp_qspi *xqspi, int size)
 	u32 count = 0, intermediate;
 
 	while ((xqspi->bytes_to_transfer > 0) && (count < size) && (xqspi->txbuf)) {
-		memcpy(&intermediate, xqspi->txbuf, 4);
-		zynqmp_gqspi_write(xqspi, GQSPI_TXD_OFST, intermediate);
-
 		if (xqspi->bytes_to_transfer >= 4) {
+			memcpy(&intermediate, xqspi->txbuf, 4);
 			xqspi->txbuf += 4;
 			xqspi->bytes_to_transfer -= 4;
+			count += 4;
 		} else {
+			memcpy(&intermediate, xqspi->txbuf,
+			       xqspi->bytes_to_transfer);
 			xqspi->txbuf += xqspi->bytes_to_transfer;
 			xqspi->bytes_to_transfer = 0;
+			count += xqspi->bytes_to_transfer;
 		}
-		count++;
+		zynqmp_gqspi_write(xqspi, GQSPI_TXD_OFST, intermediate);
 	}
 }
 
-- 
2.25.1

