[PATCH 4.9 10/32] usb: gadget: clear related members when goto fail

Greg Kroah-Hartman
2022-03-07T09:19:20Z

From: Hangyu Hua <hbh25y@gmail.com>

commit 501e38a5531efbd77d5c73c0ba838a889bfc1d74 upstream.

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>
---
drivers/usb/gadget/legacy/inode.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -1883,8 +1883,8 @@ dev_config (struct file *fd, const char

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
@@ -1901,6 +1901,9 @@ dev_config (struct file *fd, const char
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);