@@ -2155,14 +2155,18 @@ 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);
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> --- Changes in v3: - As suggested by balbi, Removed changelog from commit text. Changes in v2: - Modified commit text. drivers/usb/gadget/composite.c | 4 ++++ 1 file changed, 4 insertions(+)