usb: gadget : fix use-after-free in composite_dev_cleanup()

1. In func configfs_composite_bind() -> composite_os_desc_req_prepare():
if kmalloc fails, the pointer cdev->os_desc_req will be freed but not
set to NULL. Then it will return a failure to the upper-level function.
2. in func configfs_composite_bind() -> composite_dev_cleanup():
it will checks whether cdev->os_desc_req is NULL. If it is not NULL, it
will attempt to use it.This will lead to a use-after-free issue.

BUG: KASAN: use-after-free in composite_dev_cleanup+0xf4/0x2c0
Read of size 8 at addr 0000004827837a00 by task init/1

CPU: 10 PID: 1 Comm: init Tainted: G           O      5.10.97-oh #1
 kasan_report+0x188/0x1cc
 __asan_load8+0xb4/0xbc
 composite_dev_cleanup+0xf4/0x2c0
 configfs_composite_bind+0x210/0x7ac
 udc_bind_to_driver+0xb4/0x1ec
 usb_gadget_probe_driver+0xec/0x21c
 gadget_dev_desc_UDC_store+0x264/0x27c

Fixes: 37a3a533429e ("usb: gadget: OS Feature Descriptors support")
Cc: stable <stable@kernel.org>
Signed-off-by: Tao Xue <xuetao09@huawei.com>
Link: https://lore.kernel.org/r/20250721093908.14967-1-xuetao09@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 0f649c747584670ed3052f2d01fe61657f4c42ba..5b3866909b75240794a0bd6d1b52982586c1e638 100644 (file)
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -2465,6 +2465,11 @@ int composite_os_desc_req_prepare(struct usb_composite_dev *cdev,
        if (!cdev->os_desc_req->buf) {
                ret = -ENOMEM;
                usb_ep_free_request(ep0, cdev->os_desc_req);
+               /*
+                * Set os_desc_req to NULL so that composite_dev_cleanup()
+                * will not try to free it again.
+                */
+               cdev->os_desc_req = NULL;
                goto end;
        }
        cdev->os_desc_req->context = cdev;