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usb: gadget: uvc: Fix use are free during STREAMOFF

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There is a path that may lead to freed memory being referenced,
causing kernel panics.

The kernel panic has the following stack trace:

Workqueue: uvcgadget uvcg_video_pump.c51fb85fece46625450f86adbf92c56c.cfi_jt
pstate: 60c00085 (nZCv daIf +PAN +UAO -TCO BTYPE=--)
pc : __list_del_entry_valid+0xc0/0xd4
lr : __list_del_entry_valid+0xc0/0xd4
Call trace:
  __list_del_entry_valid+0xc0/0xd4
  uvc_video_free_request+0x60/0x98
  uvcg_video_pump+0x1cc/0x204
  process_one_work+0x21c/0x4b8
  worker_thread+0x29c/0x574
  kthread+0x158/0x1b0
  ret_from_fork+0x10/0x30

The root cause is that uvcg_video_usb_req_queue frees the uvc_request
if is_enabled is false and returns an error status. video_pump also
frees the associated request if uvcg_video_usb_req_queue returns an
error status, leading to double free and accessing garbage memory.

To fix the issue, this patch removes freeing logic from
uvcg_video_usb_req_queue, and lets the callers to the function handle
queueing errors as they see fit.

Fixes: 6acba0345b68 ("usb:gadget:uvc Do not use worker thread to pump isoc usb requests")
Tested-by: Avichal Rakesh <arakesh@google.com>
Signed-off-by: Avichal Rakesh <arakesh@google.com>
Link: https://lore.kernel.org/r/20240104215009.2252452-1-arakesh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Avichal Rakesh 2024-01-04 13:50:08 -08:00 committed by Greg Kroah-Hartman
parent 5962ded777
commit fe814b5b0f
1 changed files with 10 additions and 4 deletions
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14
drivers/usb/gadget/function/uvc_video.c
View File

@ -276,10 +276,9 @@ static int uvcg_video_usb_req_queue(struct uvc_video *video,
bool is_bulk = video->max_payload_size;
struct list_head *list = NULL;
if (!video->is_enabled) {
uvc_video_free_request(req->context, video->ep);
if (!video->is_enabled)
return -ENODEV;
}
if (queue_to_ep) {
struct uvc_request *ureq = req->context;
/*
@ -464,8 +463,15 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
* and this thread for isoc endpoints.
*/
ret = uvcg_video_usb_req_queue(video, to_queue, !is_bulk);
if (ret < 0)
if (ret < 0) {
/*
* Endpoint error, but the stream is still enabled.
* Put request back in req_free for it to be cleaned
* up later.
*/
uvcg_queue_cancel(queue, 0);
list_add_tail(&to_queue->list, &video->req_free);
}
} else {
uvc_video_free_request(ureq, ep);
}