[PATCH v2 4/5] mailbox: mailbox-test: Prevent memory leak

From: Lee Jones
Date: Wed Mar 23 2016 - 10:45:58 EST


If we set the Signal twice or more, without using it as part of a message,
memory will be re-allocated and the pointer over-written. Prevent this
potential leak by only allocating memory when there isn't any already.

Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
---
drivers/mailbox/mailbox-test.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/mailbox/mailbox-test.c b/drivers/mailbox/mailbox-test.c
index 5f4b439..58d0472 100644
--- a/drivers/mailbox/mailbox-test.c
+++ b/drivers/mailbox/mailbox-test.c
@@ -59,9 +59,12 @@ static ssize_t mbox_test_signal_write(struct file *filp,
return -EINVAL;
}

- tdev->signal = kzalloc(MBOX_MAX_SIG_LEN, GFP_KERNEL);
- if (!tdev->signal)
- return -ENOMEM;
+ /* Only allocate memory if we need to */
+ if (!tdev->signal) {
+ tdev->signal = kzalloc(MBOX_MAX_SIG_LEN, GFP_KERNEL);
+ if (!tdev->signal)
+ return -ENOMEM;
+ }

if (copy_from_user(tdev->signal, userbuf, count)) {
kfree(tdev->signal);
--
1.9.1