[PATCH] Input: synaptics-rmi4 - fix UAF of IRQ domain on driver removal

[PATCH] Input: synaptics-rmi4 - fix UAF of IRQ domain on driver removal

[Mathias Krause]

Calling irq_domain_remove() will lead to freeing the IRQ domain
prematurely. The domain is still referenced and will be attempted to get
used via rmi_free_function_list() -> rmi_unregister_function() ->
irq_dispose_mapping() -> irq_get_irq_data()'s ->domain pointer.

With PaX's MEMORY_SANITIZE this will lead to an access fault when
attempting to dereference embedded pointers, as in Torsten's report that
was faulting on the 'domain->ops->unmap' test.

Fix this by releasing the IRQ domain only after all related IRQs have
been deactivated.

Fixes: 24d28e4f1271 ("Input: synaptics-rmi4 - convert irq distribution to irq_domain")
Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
---
Torsten, could you please confirm (again) that this patch, instead of
[1], fixes the bug for you?

[1] https://lore.kernel.org/lkml/e77756aa-c0f1-44a8-bcd6-a46fe954b195@moroto.mountain/

 drivers/input/rmi4/rmi_driver.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c
index 258d5fe3d395..42eaebb3bf5c 100644
--- a/drivers/input/rmi4/rmi_driver.c
+++ b/drivers/input/rmi4/rmi_driver.c
@@ -978,12 +978,12 @@ static int rmi_driver_remove(struct device *dev)
 
 	rmi_disable_irq(rmi_dev, false);
 
+	rmi_f34_remove_sysfs(rmi_dev);
+	rmi_free_function_list(rmi_dev);
+
 	irq_domain_remove(data->irqdomain);
 	data->irqdomain = NULL;
 
-	rmi_f34_remove_sysfs(rmi_dev);
-	rmi_free_function_list(rmi_dev);
-
 	return 0;
 }
 
-- 
2.30.2

Re: [PATCH] Input: synaptics-rmi4 - fix UAF of IRQ domain on driver removal

[Dmitry Torokhov]

On Thu, Feb 22, 2024 at 03:26:54PM +0100, Mathias Krause wrote:
> Calling irq_domain_remove() will lead to freeing the IRQ domain
> prematurely. The domain is still referenced and will be attempted to get
> used via rmi_free_function_list() -> rmi_unregister_function() ->
> irq_dispose_mapping() -> irq_get_irq_data()'s ->domain pointer.
> 
> With PaX's MEMORY_SANITIZE this will lead to an access fault when
> attempting to dereference embedded pointers, as in Torsten's report that
> was faulting on the 'domain->ops->unmap' test.
> 
> Fix this by releasing the IRQ domain only after all related IRQs have
> been deactivated.
> 
> Fixes: 24d28e4f1271 ("Input: synaptics-rmi4 - convert irq distribution to irq_domain")
> Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
> Signed-off-by: Mathias Krause <minipli@grsecurity.net>

Applied, thank you.

-- 
Dmitry