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From: Mathias Krause <minipli@grsecurity.net>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Torsten Hilbrich <torsten.hilbrich@secunet.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>,
	Nick Dyer <nick@shmanahar.org>,
	Brad Spengler <spender@grsecurity.net>,
	Sasha Levin <sashal@kernel.org>,
	Jiapeng Chong <jiapeng.chong@linux.alibaba.com>,
	linux-input@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Mathias Krause <minipli@grsecurity.net>
Subject: [PATCH] Input: synaptics-rmi4 - fix UAF of IRQ domain on driver removal
Date: Thu, 22 Feb 2024 15:26:54 +0100
Message-Id: <20240222142654.856566-1-minipli@grsecurity.net>
Precedence: bulk
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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