[PATCH 5.11 188/601] spi: stm32: Fix use-after-free on unbind

Greg Kroah-Hartman
2021-05-12T17:13:15Z

From: Alain Volmat <alain.volmat@foss.st.com>

[ Upstream commit 79c6246ae8793448c05da86a4c82298eed8549b0 ]

stm32_spi_remove() accesses the driver's private data after calling
spi_unregister_master() even though that function releases the last
reference on the spi_master and thereby frees the private data.

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

Fixes: 8d559a64f00b ("spi: stm32: drop devres version of spi_register_master")

Reported-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1616052290-10887-1-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-stm32.c | 24 ++++++++++--------------
1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 8d8a32d46f2d..0318f02d6212 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -1830,7 +1830,7 @@ static int stm32_spi_probe(struct platform_device *pdev)
struct resource *res;
int ret;

- master = spi_alloc_master(&pdev->dev, sizeof(struct stm32_spi));
+ master = devm_spi_alloc_master(&pdev->dev, sizeof(struct stm32_spi));
if (!master) {
dev_err(&pdev->dev, "spi master allocation failed\n");
return -ENOMEM;
@@ -1848,18 +1848,16 @@ static int stm32_spi_probe(struct platform_device *pdev)

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
spi->base = devm_ioremap_resource(&pdev->dev, res);
- if (IS_ERR(spi->base)) {
- ret = PTR_ERR(spi->base);
- goto err_master_put;
- }
+ if (IS_ERR(spi->base))
+ return PTR_ERR(spi->base);

spi->phys_addr = (dma_addr_t)res->start;

spi->irq = platform_get_irq(pdev, 0);
- if (spi->irq <= 0) {
- ret = dev_err_probe(&pdev->dev, spi->irq, "failed to get irq\n");
- goto err_master_put;
- }
+ if (spi->irq <= 0)
+ return dev_err_probe(&pdev->dev, spi->irq,
+ "failed to get irq\n");
+
ret = devm_request_threaded_irq(&pdev->dev, spi->irq,
spi->cfg->irq_handler_event,
spi->cfg->irq_handler_thread,
@@ -1867,20 +1865,20 @@ static int stm32_spi_probe(struct platform_device *pdev)
if (ret) {
dev_err(&pdev->dev, "irq%d request failed: %d\n", spi->irq,
ret);
- goto err_master_put;
+ return ret;
}

spi->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(spi->clk)) {
ret = PTR_ERR(spi->clk);
dev_err(&pdev->dev, "clk get failed: %d\n", ret);
- goto err_master_put;
+ return ret;
}

ret = clk_prepare_enable(spi->clk);
if (ret) {
dev_err(&pdev->dev, "clk enable failed: %d\n", ret);
- goto err_master_put;
+ return ret;
}
spi->clk_rate = clk_get_rate(spi->clk);
if (!spi->clk_rate) {
@@ -1976,8 +1974,6 @@ err_dma_release:
dma_release_channel(spi->dma_rx);
err_clk_disable:
clk_disable_unprepare(spi->clk);
-err_master_put:
- spi_master_put(master);

return ret;
}
--
2.30.2