Messages in this thread Patch in this message | | | From | Dongliang Mu <> | Subject | [PATCH] media: msi2500: fix UAF in the msi2500_disconnect | Date | Wed, 17 Nov 2021 00:32:07 +0800 |
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In msi2500_probe, it invokes spi_alloc_master to allocate master controller and spi_register_master to register master controller. Then in msi2500_disconnect, it calls spi_unregister_master to unregister the master controller. And in spi_unregister_master, it calls put_device to decrease the refcount and the device object will be freed then. As a result, the dereference of dev->lock will cause a use-after-free bug.
Fix it by changing spi_alloc_master to devm_spi_alloc_master, and removing spi_master_put in the error handling code.
Note that this patch can prevent UAF occurring any more
Fixes: fd8b5f502929 ("msi2500: move msi3101 out of staging and rename") Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com> --- drivers/media/usb/msi2500/msi2500.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/media/usb/msi2500/msi2500.c b/drivers/media/usb/msi2500/msi2500.c index 71de6b4c4e4c..64c3ec9f1d0c 100644 --- a/drivers/media/usb/msi2500/msi2500.c +++ b/drivers/media/usb/msi2500/msi2500.c @@ -1220,7 +1220,7 @@ static int msi2500_probe(struct usb_interface *intf, } /* SPI master adapter */ - master = spi_alloc_master(dev->dev, 0); + master = devm_spi_alloc_master(dev->dev, 0); if (master == NULL) { ret = -ENOMEM; goto err_unregister_v4l2_dev; @@ -1233,7 +1233,6 @@ static int msi2500_probe(struct usb_interface *intf, spi_master_set_devdata(master, dev); ret = spi_register_master(master); if (ret) { - spi_master_put(master); goto err_unregister_v4l2_dev; } -- 2.25.1
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