[PATCH 5.11 294/601] spi: spi-zynqmp-gqspi: fix use-after-free in zynqmp_qspi_exec_op

Greg Kroah-Hartman
2021-05-12T17:31:02Z

From: Quanyang Wang <quanyang.wang@windriver.com>

[ Upstream commit a2c5bedb2d55dd27c642c7b9fb6886d7ad7bdb58 ]

When handling op->addr, it is using the buffer "tmpbuf" which has been
freed. This will trigger a use-after-free KASAN warning. Let's use
temporary variables to store op->addr.val and op->cmd.opcode to fix
this issue.

Fixes: 1c26372e5aa9 ("spi: spi-zynqmp-gqspi: Update driver to use spi-mem framework")
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Link: https://lore.kernel.org/r/20210416004652.2975446-5-quanyang.wang@windriver.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-zynqmp-gqspi.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
index d6ac8fe145a1..2a0be16b2eb0 100644
--- a/drivers/spi/spi-zynqmp-gqspi.c
+++ b/drivers/spi/spi-zynqmp-gqspi.c
@@ -926,8 +926,9 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
struct zynqmp_qspi *xqspi = spi_controller_get_devdata
(mem->spi->master);
int err = 0, i;
- u8 *tmpbuf;
u32 genfifoentry = 0;
+ u16 opcode = op->cmd.opcode;
+ u64 opaddr;

dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
@@ -940,14 +941,8 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
genfifoentry |= xqspi->genfifobus;

if (op->cmd.opcode) {
- tmpbuf = kzalloc(op->cmd.nbytes, GFP_KERNEL | GFP_DMA);
- if (!tmpbuf) {
- mutex_unlock(&xqspi->op_lock);
- return -ENOMEM;
- }
- tmpbuf[0] = op->cmd.opcode;
reinit_completion(&xqspi->data_completion);
- xqspi->txbuf = tmpbuf;
+ xqspi->txbuf = &opcode;
xqspi->rxbuf = NULL;
xqspi->bytes_to_transfer = op->cmd.nbytes;
xqspi->bytes_to_receive = 0;
@@ -961,13 +956,12 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
if (!wait_for_completion_timeout
(&xqspi->data_completion, msecs_to_jiffies(1000))) {
err = -ETIMEDOUT;
- kfree(tmpbuf);
goto return_err;
}
- kfree(tmpbuf);
}

if (op->addr.nbytes) {
+ xqspi->txbuf = &opaddr;
for (i = 0; i < op->addr.nbytes; i++) {
*(((u8 *)xqspi->txbuf) + i) = op->addr.val >>
(8 * (op->addr.nbytes - i - 1));
--
2.30.2