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Message-ID: <db6746a7-6d63-4d07-a632-ed7ae6030631@I-love.SAKURA.ne.jp>
Date: Mon, 3 Jun 2024 22:01:43 +0900
From: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
To: LKML <linux-kernel@...r.kernel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH v2] Input: MT - limit max slots
syzbot is reporting too large allocation at input_mt_init_slots(), for
num_slots is supplied from userspace using ioctl(UI_DEV_CREATE).
Since nobody knows possible max slots, this patch chose 1024.
Reported-by: syzbot <syzbot+0122fa359a69694395d5@...kaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=0122fa359a69694395d5
Suggested-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
---
Changes in v2:
Limit max slots instead of using __GFP_NOWARN.
drivers/input/input-mt.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index 14b53dac1253..6b04a674f832 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -46,6 +46,9 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
return 0;
if (mt)
return mt->num_slots != num_slots ? -EINVAL : 0;
+ /* Arbitrary limit for avoiding too large memory allocation. */
+ if (num_slots > 1024)
+ return -EINVAL;
mt = kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL);
if (!mt)
--
2.18.4
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