From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 29 Jan 2021 14:37:24 +0000 (+0300)
Subject: mfd: wm831x-auxadc: Prevent use after free in wm831x_auxadc_read_irq()
X-Git-Tag: v5.10.25~806
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b1b904813755d825eff31222d2d24b05638c0c52;p=platform%2Fkernel%2Flinux-rpi.git

mfd: wm831x-auxadc: Prevent use after free in wm831x_auxadc_read_irq()

[ Upstream commit 26783d74cc6a440ee3ef9836a008a697981013d0 ]

The "req" struct is always added to the "wm831x->auxadc_pending" list,
but it's only removed from the list on the success path.  If a failure
occurs then the "req" struct is freed but it's still on the list,
leading to a use after free.

Fixes: 78bb3688ea18 ("mfd: Support multiple active WM831x AUXADC conversions")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/mfd/wm831x-auxadc.c b/drivers/mfd/wm831x-auxadc.c
index 8a7cc0f..65b98f3 100644
--- a/drivers/mfd/wm831x-auxadc.c
+++ b/drivers/mfd/wm831x-auxadc.c
@@ -93,11 +93,10 @@ static int wm831x_auxadc_read_irq(struct wm831x *wm831x,
 	wait_for_completion_timeout(&req->done, msecs_to_jiffies(500));
 
 	mutex_lock(&wm831x->auxadc_lock);
-
-	list_del(&req->list);
 	ret = req->val;
 
 out:
+	list_del(&req->list);
 	mutex_unlock(&wm831x->auxadc_lock);
 
 	kfree(req);