| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 43/95] Input: synaptics-rmi4 - really fix attn_data use-after-free | Date | Mon, 1 Jun 2020 19:53:43 +0200 |
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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.Ic8f898e0147beeee2c005ee7b20f1aebdef1e7eb@changeid 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 162526a0d463..24a1ff34964c 100644 --- a/drivers/input/rmi4/rmi_driver.c +++ b/drivers/input/rmi4/rmi_driver.c @@ -208,7 +208,7 @@ 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)) -- 2.25.1
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