Commit 717adfda authored by Daniel Rosenberg's avatar Daniel Rosenberg Committed by Jiri Kosina
Browse files

HID: debug: check length before copy_to_user() 



If our length is greater than the size of the buffer, we
overflow the buffer

Cc: stable@vger.kernel.org
Signed-off-by: default avatarDaniel Rosenberg <drosen@google.com>
Reviewed-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 8f732850

drivers/hid/hid-debug.c

+7 −1
Original line number Diff line number Diff line
@@ -1154,6 +1154,8 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer, 
			goto out;

		if (list->tail > list->head) {

			len = list->tail - list->head;

			if (len > count)

				len = count;



			if (copy_to_user(buffer + ret, &list->hid_debug_buf[list->head], len)) {

				ret = -EFAULT;
@@ -1163,6 +1165,8 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer, 
			list->head += len;

		} else {

			len = HID_DEBUG_BUFSIZE - list->head;

			if (len > count)

				len = count;



			if (copy_to_user(buffer, &list->hid_debug_buf[list->head], len)) {

				ret = -EFAULT;
@@ -1170,6 +1174,8 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer, 
			}

			list->head = 0;

			ret += len;

			count -= len;

			if (count > 0)

				goto copy_rest;

		}