From: Chandana Kishori Chiluveru cchiluve@codeaurora.org
[ Upstream commit 1c20c89b0421b52b2417bb0f62a611bc669eda1d ]
composite_dev_cleanup call from the failure of configfs_composite_bind frees up the cdev->os_desc_req and cdev->req. If the previous calls of bind and unbind is successful these will carry stale values.
Consider the below sequence of function calls: configfs_composite_bind() composite_dev_prepare() - Allocate cdev->req, cdev->req->buf composite_os_desc_req_prepare() - Allocate cdev->os_desc_req, cdev->os_desc_req->buf configfs_composite_unbind() composite_dev_cleanup() - free the cdev->os_desc_req->buf and cdev->req->buf Next composition switch configfs_composite_bind() - If it fails goto err_comp_cleanup will call the composite_dev_cleanup() function composite_dev_cleanup() - calls kfree up with the stale values of cdev->req->buf and cdev->os_desc_req from the previous configfs_composite_bind call. The free call on these stale values leads to double free.
Hence, Fix this issue by setting request and buffer pointer to NULL after kfree.
Signed-off-by: Chandana Kishori Chiluveru cchiluve@codeaurora.org Signed-off-by: Felipe Balbi felipe.balbi@linux.intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/gadget/composite.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c index dfcabadeed01b..33115e19756c6 100644 --- a/drivers/usb/gadget/composite.c +++ b/drivers/usb/gadget/composite.c @@ -2156,14 +2156,18 @@ void composite_dev_cleanup(struct usb_composite_dev *cdev) usb_ep_dequeue(cdev->gadget->ep0, cdev->os_desc_req);
kfree(cdev->os_desc_req->buf); + cdev->os_desc_req->buf = NULL; usb_ep_free_request(cdev->gadget->ep0, cdev->os_desc_req); + cdev->os_desc_req = NULL; } if (cdev->req) { if (cdev->setup_pending) usb_ep_dequeue(cdev->gadget->ep0, cdev->req);
kfree(cdev->req->buf); + cdev->req->buf = NULL; usb_ep_free_request(cdev->gadget->ep0, cdev->req); + cdev->req = NULL; } cdev->next_string_id = 0; device_remove_file(&cdev->gadget->dev, &dev_attr_suspended);