From 7d233f93594f0d9afe44e9409131a8d6ad4f593c Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 5 May 2023 12:22:09 +0300 Subject: [PATCH] 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 Reviewed-by: Lee Jones Signed-off-by: Jassi Brar Signed-off-by: Sasha Levin --- drivers/mailbox/mailbox-test.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/mailbox/mailbox-test.c b/drivers/mailbox/mailbox-test.c index 6dd5b96..abcee58 100644 --- a/drivers/mailbox/mailbox-test.c +++ b/drivers/mailbox/mailbox-test.c @@ -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; -- 2.7.4