HID: hiddev: Fix slab-out-of-bounds write in hiddev_ioctl_usage()

`uref->usage_index` is not always being properly checked, causing
hiddev_ioctl_usage() to go out of bounds under some cases. Fix it.

Reported-by: syzbot+34ee1b45d88571c2fa8b@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=f2aebe90b8c56806b050a20b36f51ed6acabe802
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
index 4140dea..4f97e6c 100644 (file)
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -519,12 +519,16 @@ static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd,
 
                switch (cmd) {
                case HIDIOCGUSAGE:
+                       if (uref->usage_index >= field->report_count)
+                               goto inval;
                        uref->value = field->value[uref->usage_index];
                        if (copy_to_user(user_arg, uref, sizeof(*uref)))
                                goto fault;
                        goto goodreturn;
 
                case HIDIOCSUSAGE:
+                       if (uref->usage_index >= field->report_count)
+                               goto inval;
                        field->value[uref->usage_index] = uref->value;
                        goto goodreturn;