Unverified Commit b341c117 authored by Marc Kleine-Budde's avatar Marc Kleine-Budde Committed by Mark Brown
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spi: spi-fsl-lpspi: fix teardown order issue (UAF) 



There is a teardown order issue in the driver. The SPI controller is
registered using devm_spi_register_controller(), which delays
unregistration of the SPI controller until after the fsl_lpspi_remove()
function returns.

As the fsl_lpspi_remove() function synchronously tears down the DMA
channels, a running SPI transfer triggers the following NULL pointer
dereference due to use after free:

| fsl_lpspi 42550000.spi: I/O Error in DMA RX
| Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[...]
| Call trace:
|  fsl_lpspi_dma_transfer+0x260/0x340 [spi_fsl_lpspi]
|  fsl_lpspi_transfer_one+0x198/0x448 [spi_fsl_lpspi]
|  spi_transfer_one_message+0x49c/0x7c8
|  __spi_pump_transfer_message+0x120/0x420
|  __spi_sync+0x2c4/0x520
|  spi_sync+0x34/0x60
|  spidev_message+0x20c/0x378 [spidev]
|  spidev_ioctl+0x398/0x750 [spidev]
[...]

Switch from devm_spi_register_controller() to spi_register_controller() in
fsl_lpspi_probe() and add the corresponding spi_unregister_controller() in
fsl_lpspi_remove().

Fixes: 5314987d ("spi: imx: add lpspi bus driver")
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
Link: https://patch.msgid.link/20260319-spi-fsl-lpspi-fixes-v1-1-b433e435b2d8@pengutronix.de


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 8d2e0cb3

drivers/spi/spi-fsl-lpspi.c

+2 −1
Original line number Diff line number Diff line
@@ -1009,7 +1009,7 @@ static int fsl_lpspi_probe(struct platform_device *pdev) 
		enable_irq(irq);

	}



	ret = devm_spi_register_controller(&pdev->dev, controller);

	ret = spi_register_controller(controller);

	if (ret < 0) {

		dev_err_probe(&pdev->dev, ret, "spi_register_controller error\n");

		goto free_dma;
@@ -1035,6 +1035,7 @@ static void fsl_lpspi_remove(struct platform_device *pdev) 
	struct fsl_lpspi_data *fsl_lpspi =

				spi_controller_get_devdata(controller);



	spi_unregister_controller(controller);

	fsl_lpspi_dma_exit(controller);



	pm_runtime_dont_use_autosuspend(fsl_lpspi->dev);