usb: gadget: clear related members when goto fail

dev->config and dev->hs_config and dev->dev need to be cleaned if
dev_config fails to avoid UAF.

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Link: https://lore.kernel.org/r/20211231172138.7993-3-hbh25y@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index eaad03c..25c8809 100644 (file)
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -1875,8 +1875,8 @@ dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 
        value = usb_gadget_probe_driver(&gadgetfs_driver);
        if (value != 0) {
-               kfree (dev->buf);
-               dev->buf = NULL;
+               spin_lock_irq(&dev->lock);
+               goto fail;
        } else {
                /* at this point "good" hardware has for the first time
                 * let the USB the host see us.  alternatively, if users
@@ -1893,6 +1893,9 @@ dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
        return value;
 
 fail:
+       dev->config = NULL;
+       dev->hs_config = NULL;
+       dev->dev = NULL;
        spin_unlock_irq (&dev->lock);
        pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev);
        kfree (dev->buf);