Commit 6841a56b authored May 05, 2023 by Dan Carpenter Committed by Lee Jones Jun 12, 2023

UPSTREAM: mailbox: mailbox-test: fix a locking issue in mbox_test_message_write()



[ Upstream commit 8fe72b76db79d694858e872370df49676bc3be8c ]

There was a bug where this code forgot to unlock the tdev->mutex if the
kzalloc() failed.  Fix this issue, by moving the allocation outside the
lock.

Bug: 275340532
Fixes: 2d1e952a2b8e ("mailbox: mailbox-test: Fix potential double-free in mbox_test_message_write()")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Lee Jones <lee@kernel.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 7d233f93594f0d9afe44e9409131a8d6ad4f593c)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I7a4a1bf06abbb2092aceb72610e3f894b2bfbf0f

parent 229c9edd

drivers/mailbox/mailbox-test.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -97,6 +97,7 @@ static ssize_t mbox_test_message_write(struct file *filp,
		size_t count, loff_t *ppos)
		{
		struct mbox_test_device *tdev = filp->private_data;
		char *message;
		void *data;
		int ret;

		@@ -112,12 +113,13 @@ static ssize_t mbox_test_message_write(struct file *filp,
		return -EINVAL;
		}

		mutex_lock(&tdev->mutex);

		tdev->message = kzalloc(MBOX_MAX_MSG_LEN, GFP_KERNEL);
		if (!tdev->message)
		message = kzalloc(MBOX_MAX_MSG_LEN, GFP_KERNEL);
		if (!message)
		return -ENOMEM;

		mutex_lock(&tdev->mutex);

		tdev->message = message;
		ret = copy_from_user(tdev->message, userbuf, count);
		if (ret) {
		ret = -EFAULT;