[PATCH 5.19 0271/1157] spi: tegra20-slink: fix UAF in tegra_slink_remove()

Greg Kroah-Hartman
2022-08-15T23:02:35Z

From: Yang Yingliang <yangyingliang@huawei.com>

[ Upstream commit 7e9984d183bb1e99e766c5c2b950ff21f7f7b6c0 ]

After calling spi_unregister_master(), the refcount of master will
be decrease to 0, and it will be freed in spi_controller_release(),
the device data also will be freed, so it will lead a UAF when using
'tspi'. To fix this, get the master before unregister and put it when
finish using it.

Fixes: 26c863418221 ("spi: tegra20-slink: Don't use resource-managed spi_register helper")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220713094024.1508869-1-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-tegra20-slink.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-tegra20-slink.c b/drivers/spi/spi-tegra20-slink.c
index 38360434d6e9..148043d0c2b8 100644
--- a/drivers/spi/spi-tegra20-slink.c
+++ b/drivers/spi/spi-tegra20-slink.c
@@ -1136,7 +1136,7 @@ static int tegra_slink_probe(struct platform_device *pdev)

static int tegra_slink_remove(struct platform_device *pdev)
{
- struct spi_master *master = platform_get_drvdata(pdev);
+ struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
struct tegra_slink_data *tspi = spi_master_get_devdata(master);

spi_unregister_master(master);
@@ -1151,6 +1151,7 @@ static int tegra_slink_remove(struct platform_device *pdev)
if (tspi->rx_dma_chan)
tegra_slink_deinit_dma_param(tspi, true);

+ spi_master_put(master);
return 0;
}

--
2.35.1