HID: wacom: handle kzalloc() allocation failure in wacom_wac_queue_flush()

During wacom_wac_queue_flush() the code calls
kzalloc() to allocate a zero initialised buffer
which it uses as a storage buffer to get data
from the fifo via kfifo_out(). However it does not
check kzalloc() for allocation failure which returns
NULL and could potentially lead to a NULL deref.

Fix this by checking for kzalloc() failure and skipping
the current entry if allocation failure occurs.

Fixes: 5e013ad20689 ("HID: wacom: Remove static WACOM_PKGLEN_MAX limit")
Signed-off-by: Qasim Ijaz <qasdev00@gmail.com>
Reviewed-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index 97393a3083caef55b67892df41f4296814b7c420..43d892810c9eebd3d4f4cc7861f06b0e90db5ddb 100644 (file)
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -70,10 +70,16 @@ static void wacom_wac_queue_flush(struct hid_device *hdev,
 {
        while (!kfifo_is_empty(fifo)) {
                int size = kfifo_peek_len(fifo);
-               u8 *buf = kzalloc(size, GFP_KERNEL);
+               u8 *buf;
                unsigned int count;
                int err;
 
+               buf = kzalloc(size, GFP_KERNEL);
+               if (!buf) {
+                       kfifo_skip(fifo);
+                       continue;
+               }
+
                count = kfifo_out(fifo, buf, size);
                if (count != size) {
                        // Hard to say what is the "right" action in this