From: Evan Green evgreen@chromium.org
[ Upstream commit d5a5e5b5fa7b86c05bf073acc0ba98fa280174ec ]
Fix a use-after-free noticed by running with KASAN enabled. If rmi_irq_fn() is run twice in a row, then rmi_f11_attention() (among others) will end up reading from drvdata->attn_data.data, which was freed and left dangling in rmi_irq_fn().
Commit 55edde9fff1a ("Input: synaptics-rmi4 - prevent UAF reported by KASAN") correctly identified and analyzed this bug. However the attempted fix only NULLed out a local variable, missing the fact that drvdata->attn_data is a struct, not a pointer.
NULL out the correct pointer in the driver data to prevent the attention functions from copying from it.
Fixes: 55edde9fff1a ("Input: synaptics-rmi4 - prevent UAF reported by KASAN") Fixes: b908d3cd812a ("Input: synaptics-rmi4 - allow to add attention data") Signed-off-by: Evan Green evgreen@chromium.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200427145537.1.Ic8f898e0147beeee2c005ee7b20f1aeb... Signed-off-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/input/rmi4/rmi_driver.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c index 190b9974526b..c18e1a25bca6 100644 --- a/drivers/input/rmi4/rmi_driver.c +++ b/drivers/input/rmi4/rmi_driver.c @@ -205,7 +205,7 @@ static irqreturn_t rmi_irq_fn(int irq, void *dev_id)
if (count) { kfree(attn_data.data); - attn_data.data = NULL; + drvdata->attn_data.data = NULL; }
if (!kfifo_is_empty(&drvdata->attn_fifo))