| Message ID | 20200923131026.20707-1-s.hauer@pengutronix.de (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 530b5affc675ade5db4a03f04ed7cd66806c8a1a |
| Headers | show |
| Series | spi: fsl-dspi: fix use-after-free in remove path | expand |
On Wed, 23 Sep 2020 15:10:26 +0200, Sascha Hauer wrote: > spi_unregister_controller() not only unregisters the controller, but > also frees the controller. This will free the driver data with it, so > we must not access it later dspi_remove(). > > Solve this by allocating the driver data separately from the SPI > controller. Applied to https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next Thanks! [1/1] spi: fsl-dspi: fix use-after-free in remove path commit: 530b5affc675ade5db4a03f04ed7cd66806c8a1a All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark
diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c index 91c6affe139c..aae9f9a7aea6 100644 --- a/drivers/spi/spi-fsl-dspi.c +++ b/drivers/spi/spi-fsl-dspi.c @@ -1273,11 +1273,14 @@ static int dspi_probe(struct platform_device *pdev) void __iomem *base; bool big_endian; - ctlr = spi_alloc_master(&pdev->dev, sizeof(struct fsl_dspi)); + dspi = devm_kzalloc(&pdev->dev, sizeof(*dspi), GFP_KERNEL); + if (!dspi) + return -ENOMEM; + + ctlr = spi_alloc_master(&pdev->dev, 0); if (!ctlr) return -ENOMEM; - dspi = spi_controller_get_devdata(ctlr); dspi->pdev = pdev; dspi->ctlr = ctlr; @@ -1414,7 +1417,7 @@ static int dspi_probe(struct platform_device *pdev) if (dspi->devtype_data->trans_mode != DSPI_DMA_MODE) ctlr->ptp_sts_supported = true; - platform_set_drvdata(pdev, ctlr); + platform_set_drvdata(pdev, dspi); ret = spi_register_controller(ctlr); if (ret != 0) { @@ -1437,8 +1440,7 @@ static int dspi_probe(struct platform_device *pdev) static int dspi_remove(struct platform_device *pdev) { - struct spi_controller *ctlr = platform_get_drvdata(pdev); - struct fsl_dspi *dspi = spi_controller_get_devdata(ctlr); + struct fsl_dspi *dspi = platform_get_drvdata(pdev); /* Disconnect from the SPI framework */ spi_unregister_controller(dspi->ctlr);
spi_unregister_controller() not only unregisters the controller, but also frees the controller. This will free the driver data with it, so we must not access it later dspi_remove(). Solve this by allocating the driver data separately from the SPI controller. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> --- This fixes the issue reported at https://marc.info/?l=linux-spi&m=160068648808293&w=2 for the fsl-dspi driver in the way Mark suggested. A whole lot of other SPI drivers are affected by this issue and need a similar fix. Here is a fix for the driver I currently care about. drivers/spi/spi-fsl-dspi.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)