[PATCH 1/1] spi: imx: fix issue when tx_buf or rx_buf is NULL

[jiada_wang]

From: Jiada Wang <jiada_w...@mentor.com>

In case either transfer->tx_buf or transfer->rx_buf is NULL,
manipulation of buffer in spi_imx_u32_swap_u[8|16]() will cause
NULL pointer dereference crash.

Add buffer check at very beginning of spi_imx_u32_swap_u[8|16](),
to avoid such crash.

Signed-off-by: Jiada Wang <jiada_w...@mentor.com>
Reported-by: Leonard Crestez <leonard.cres...@nxp.com>
---
 drivers/spi/spi-imx.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 782045f..19b30cf 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -288,6 +288,9 @@ static void spi_imx_u32_swap_u8(struct spi_transfer 
*transfer, u32 *buf)
 {
        int i;
 
+       if (!buf)
+               return;
+
        for (i = 0; i < transfer->len / 4; i++)
                *(buf + i) = cpu_to_be32(*(buf + i));
 }
@@ -296,6 +299,9 @@ static void spi_imx_u32_swap_u16(struct spi_transfer 
*transfer, u32 *buf)
 {
        int i;
 
+       if (!buf)
+               return;
+
        for (i = 0; i < transfer->len / 4; i++) {
                u16 *temp = (u16 *)buf;
 
-- 
2.7.4