[PATCH 6.8 640/715] spi: lpspi: Avoid potential use-after-free in probe()

Sasha Levin
2024-03-24T22:45:32Z

From: Alexander Sverdlin <alexander.sverdlin@siemens.com>

[ Upstream commit 2ae0ab0143fcc06190713ed81a6486ed0ad3c861 ]

fsl_lpspi_probe() is allocating/disposing memory manually with
spi_alloc_host()/spi_alloc_target(), but uses
devm_spi_register_controller(). In case of error after the latter call the
memory will be explicitly freed in the probe function by
spi_controller_put() call, but used afterwards by "devm" management outside
probe() (spi_unregister_controller() <- devm_spi_unregister() below).

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000070
...
Call trace:
kernfs_find_ns
kernfs_find_and_get_ns
sysfs_remove_group
sysfs_remove_groups
device_remove_attrs
device_del
spi_unregister_controller
devm_spi_unregister
release_nodes
devres_release_all
really_probe
driver_probe_device
__device_attach_driver
bus_for_each_drv
__device_attach
device_initial_probe
bus_probe_device
deferred_probe_work_func
process_one_work
worker_thread
kthread
ret_from_fork

Fixes: 5314987de5e5 ("spi: imx: add lpspi bus driver")
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Link: https://msgid.link/r/20240312112050.2503643-1-alexander.sverdlin@siemens.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-fsl-lpspi.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c
index 11991eb126364..079035db7dd85 100644
--- a/drivers/spi/spi-fsl-lpspi.c
+++ b/drivers/spi/spi-fsl-lpspi.c
@@ -830,11 +830,11 @@ static int fsl_lpspi_probe(struct platform_device *pdev)

is_target = of_property_read_bool((&pdev->dev)->of_node, "spi-slave");
if (is_target)
- controller = spi_alloc_target(&pdev->dev,
- sizeof(struct fsl_lpspi_data));
+ controller = devm_spi_alloc_target(&pdev->dev,
+ sizeof(struct fsl_lpspi_data));
else
- controller = spi_alloc_host(&pdev->dev,
- sizeof(struct fsl_lpspi_data));
+ controller = devm_spi_alloc_host(&pdev->dev,
+ sizeof(struct fsl_lpspi_data));

if (!controller)
return -ENOMEM;
--
2.43.0