[PATCH 5.10 641/717] spi: pxa2xx: Fix use-after-free on unbind

From: Greg Kroah-Hartman
Date: Mon Dec 28 2020 - 09:32:21 EST


From: Lukas Wunner <lukas@xxxxxxxxx>

commit 5626308bb94d9f930aa5f7c77327df4c6daa7759 upstream.

pxa2xx_spi_remove() accesses the driver's private data after calling
spi_unregister_controller() even though that function releases the last
reference on the spi_controller and thereby frees the private data.

Fix by switching over to the new devm_spi_alloc_master/slave() helper
which keeps the private data accessible until the driver has unbound.

Fixes: 32e5b57232c0 ("spi: pxa2xx: Fix controller unregister order")
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v2.6.17+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc: <stable@xxxxxxxxxxxxxxx> # v2.6.17+: 32e5b57232c0: spi: pxa2xx: Fix controller unregister order
Cc: <stable@xxxxxxxxxxxxxxx> # v2.6.17+
Link: https://lore.kernel.org/r/5764b04d4a6e43069ebb7808f64c2f774ac6f193.1607286887.git.lukas@xxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/spi/spi-pxa2xx.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -1686,9 +1686,9 @@ static int pxa2xx_spi_probe(struct platf
}

if (platform_info->is_slave)
- controller = spi_alloc_slave(dev, sizeof(struct driver_data));
+ controller = devm_spi_alloc_slave(dev, sizeof(*drv_data));
else
- controller = spi_alloc_master(dev, sizeof(struct driver_data));
+ controller = devm_spi_alloc_master(dev, sizeof(*drv_data));

if (!controller) {
dev_err(&pdev->dev, "cannot alloc spi_controller\n");
@@ -1911,7 +1911,6 @@ out_error_dma_irq_alloc:
free_irq(ssp->irq, drv_data);

out_error_controller_alloc:
- spi_controller_put(controller);
pxa_ssp_free(ssp);
return status;
}