Unverified Commit 63c5395b authored by Lukas Wunner's avatar Lukas Wunner Committed by Mark Brown
Browse files

spi: bcm-qspi: Fix use-after-free on unbind 



bcm_qspi_remove() calls spi_unregister_master() even though
bcm_qspi_probe() calls devm_spi_register_master().  The spi_master is
therefore unregistered and freed twice on unbind.

Moreover, since commit 0392727c ("spi: bcm-qspi: Handle clock probe
deferral"), bcm_qspi_probe() leaks the spi_master allocation if the call
to devm_clk_get_optional() fails.

Fix by switching over to the new devm_spi_alloc_master() helper which
keeps the private data accessible until the driver has unbound and also
avoids the spi_master leak on probe.

While at it, fix an ordering issue in bcm_qspi_remove() wherein
spi_unregister_master() is called after uninitializing the hardware,
disabling the clock and freeing an IRQ data structure.  The correct
order is to call spi_unregister_master() *before* those teardown steps
because bus accesses may still be ongoing until that function returns.

Fixes: fa236a7e ("spi: bcm-qspi: Add Broadcom MSPI driver")
Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v4.9+: 123456789abc: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v4.9+
Cc: Kamal Dasu <kdasu.kdev@gmail.com>
Acked-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Tested-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/5e31a9a59fd1c0d0b795b2fe219f25e5ee855f9d.1605121038.git.lukas@wunner.de


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent e13ee6cc

drivers/spi/spi-bcm-qspi.c

+12 −22
Original line number Diff line number Diff line
@@ -1327,7 +1327,7 @@ int bcm_qspi_probe(struct platform_device *pdev, 


	data = of_id->data;



	master = spi_alloc_master(dev, sizeof(struct bcm_qspi));

	master = devm_spi_alloc_master(dev, sizeof(struct bcm_qspi));

	if (!master) {

		dev_err(dev, "error allocating spi_master\n");

		return -ENOMEM;
@@ -1367,21 +1367,17 @@ int bcm_qspi_probe(struct platform_device *pdev, 


	if (res) {

		qspi->base[MSPI]  = devm_ioremap_resource(dev, res);

		if (IS_ERR(qspi->base[MSPI])) {

			ret = PTR_ERR(qspi->base[MSPI]);

			goto qspi_resource_err;

		}

		if (IS_ERR(qspi->base[MSPI]))

			return PTR_ERR(qspi->base[MSPI]);

	} else {

		goto qspi_resource_err;

		return 0;

	}



	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "bspi");

	if (res) {

		qspi->base[BSPI]  = devm_ioremap_resource(dev, res);

		if (IS_ERR(qspi->base[BSPI])) {

			ret = PTR_ERR(qspi->base[BSPI]);

			goto qspi_resource_err;

		}

		if (IS_ERR(qspi->base[BSPI]))

			return PTR_ERR(qspi->base[BSPI]);

		qspi->bspi_mode = true;

	} else {

		qspi->bspi_mode = false;
@@ -1392,18 +1388,14 @@ int bcm_qspi_probe(struct platform_device *pdev, 
	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cs_reg");

	if (res) {

		qspi->base[CHIP_SELECT]  = devm_ioremap_resource(dev, res);

		if (IS_ERR(qspi->base[CHIP_SELECT])) {

			ret = PTR_ERR(qspi->base[CHIP_SELECT]);

			goto qspi_resource_err;

		}

		if (IS_ERR(qspi->base[CHIP_SELECT]))

			return PTR_ERR(qspi->base[CHIP_SELECT]);

	}



	qspi->dev_ids = kcalloc(num_irqs, sizeof(struct bcm_qspi_dev_id),

				GFP_KERNEL);

	if (!qspi->dev_ids) {

		ret = -ENOMEM;

		goto qspi_resource_err;

	}

	if (!qspi->dev_ids)

		return -ENOMEM;



	for (val = 0; val < num_irqs; val++) {

		irq = -1;
@@ -1484,7 +1476,7 @@ int bcm_qspi_probe(struct platform_device *pdev, 
	qspi->xfer_mode.addrlen = -1;

	qspi->xfer_mode.hp = -1;



	ret = devm_spi_register_master(&pdev->dev, master);

	ret = spi_register_master(master);

	if (ret < 0) {

		dev_err(dev, "can't register master\n");

		goto qspi_reg_err;
@@ -1497,8 +1489,6 @@ qspi_reg_err: 
	clk_disable_unprepare(qspi->clk);

qspi_probe_err:

	kfree(qspi->dev_ids);

qspi_resource_err:

	spi_master_put(master);

	return ret;

}

/* probe function to be called by SoC specific platform driver probe */
@@ -1508,10 +1498,10 @@ int bcm_qspi_remove(struct platform_device *pdev) 
{

	struct bcm_qspi *qspi = platform_get_drvdata(pdev);



	spi_unregister_master(qspi->master);

	bcm_qspi_hw_uninit(qspi);

	clk_disable_unprepare(qspi->clk);

	kfree(qspi->dev_ids);

	spi_unregister_master(qspi->master);



	return 0;

}

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