Commit b1fc302c authored May 05, 2023 by Dan Carpenter Committed by Greg Kroah-Hartman Jun 09, 2023

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.

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>

parent 35027a6a

drivers/mailbox/mailbox-test.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -101,6 +101,7 @@ 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;

		@@ -116,12 +117,13 @@ 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;