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Message-ID: <20240805175934.3257938-1-sashal@kernel.org>
Date: Mon, 5 Aug 2024 13:59:33 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
stable@...r.kernel.org
Cc: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
syzbot <syzbot+0122fa359a69694395d5@...kaller.appspotmail.com>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Sasha Levin <sashal@...nel.org>,
linux-input@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19] Input: MT - limit max slots
From: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
[ Upstream commit 99d3bf5f7377d42f8be60a6b9cb60fb0be34dceb ]
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>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
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 6c7326c93721c..fd01c9306e66c 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -48,6 +48,9 @@ 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)
--
2.43.0
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