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Code Issues Releases Wiki Activity

usb: gadget: uvc: Allocate uvc_requests one at a time

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Currently, the uvc gadget driver allocates all uvc_requests as one array
and deallocates them all when the video stream stops. This includes
de-allocating all the usb_requests associated with those uvc_requests.
This can lead to use-after-free issues if any of those de-allocated
usb_requests were still owned by the usb controller.

This patch is 1 of 2 patches addressing the use-after-free issue.
Instead of bulk allocating all uvc_requests as an array, this patch
allocates uvc_requests one at a time, which should allows for similar
granularity when deallocating the uvc_requests. This patch has no
functional changes other than allocating each uvc_request separately,
and similarly freeing each of them separately.

Link: https://lore.kernel.org/7cd81649-2795-45b6-8c10-b7df1055020d@google.com
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Suggested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Tested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Avichal Rakesh <arakesh@google.com>
Link: https://lore.kernel.org/r/20231109004104.3467968-2-arakesh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Avichal Rakesh 2023-11-08 16:41:02 -08:00 committed by Greg Kroah-Hartman
parent 991544dc57
commit aeb686a98a
2 changed files with 52 additions and 41 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
drivers/usb/gadget/function/uvc.h
View file

@ -81,6 +81,7 @@ struct uvc_request {
struct sg_table sgt;
u8 header[UVCG_REQUEST_HEADER_LEN];
struct uvc_buffer *last_buf;
struct list_head list;
};
struct uvc_video {
@ -102,7 +103,7 @@ struct uvc_video {
/* Requests */
unsigned int req_size;
struct uvc_request *ureq;
struct list_head ureqs; /* all uvc_requests allocated by uvc_video */
struct list_head req_free;
spinlock_t req_lock;

90
drivers/usb/gadget/function/uvc_video.c
View file

@ -227,6 +227,24 @@ uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
* Request handling
*/
static void
uvc_video_free_request(struct uvc_request *ureq, struct usb_ep *ep)
{
sg_free_table(&ureq->sgt);
if (ureq->req && ep) {
usb_ep_free_request(ep, ureq->req);
ureq->req = NULL;
}
kfree(ureq->req_buffer);
ureq->req_buffer = NULL;
if (!list_empty(&ureq->list))
list_del_init(&ureq->list);
kfree(ureq);
}
static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
{
int ret;
@ -293,27 +311,12 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
static int
uvc_video_free_requests(struct uvc_video *video)
{
unsigned int i;
struct uvc_request *ureq, *temp;
if (video->ureq) {
for (i = 0; i < video->uvc_num_requests; ++i) {
sg_free_table(&video->ureq[i].sgt);
if (video->ureq[i].req) {
usb_ep_free_request(video->ep, video->ureq[i].req);
video->ureq[i].req = NULL;
}
if (video->ureq[i].req_buffer) {
kfree(video->ureq[i].req_buffer);
video->ureq[i].req_buffer = NULL;
}
}
kfree(video->ureq);
video->ureq = NULL;
}
list_for_each_entry_safe(ureq, temp, &video->ureqs, list)
uvc_video_free_request(ureq, video->ep);
INIT_LIST_HEAD(&video->ureqs);
INIT_LIST_HEAD(&video->req_free);
video->req_size = 0;
return 0;
@ -322,6 +325,7 @@ uvc_video_free_requests(struct uvc_video *video)
static int
uvc_video_alloc_requests(struct uvc_video *video)
{
struct uvc_request *ureq;
unsigned int req_size;
unsigned int i;
int ret = -ENOMEM;
@ -332,29 +336,33 @@ uvc_video_alloc_requests(struct uvc_video *video)
* max_t(unsigned int, video->ep->maxburst, 1)
* (video->ep->mult);
video->ureq = kcalloc(video->uvc_num_requests, sizeof(struct uvc_request), GFP_KERNEL);
if (video->ureq == NULL)
return -ENOMEM;
for (i = 0; i < video->uvc_num_requests; ++i) {
video->ureq[i].req_buffer = kmalloc(req_size, GFP_KERNEL);
if (video->ureq[i].req_buffer == NULL)
for (i = 0; i < video->uvc_num_requests; i++) {
ureq = kzalloc(sizeof(struct uvc_request), GFP_KERNEL);
if (ureq == NULL)
goto error;
video->ureq[i].req = usb_ep_alloc_request(video->ep, GFP_KERNEL);
if (video->ureq[i].req == NULL)
INIT_LIST_HEAD(&ureq->list);
list_add_tail(&ureq->list, &video->ureqs);
ureq->req_buffer = kmalloc(req_size, GFP_KERNEL);
if (ureq->req_buffer == NULL)
goto error;
video->ureq[i].req->buf = video->ureq[i].req_buffer;
video->ureq[i].req->length = 0;
video->ureq[i].req->complete = uvc_video_complete;
video->ureq[i].req->context = &video->ureq[i];
video->ureq[i].video = video;
video->ureq[i].last_buf = NULL;
ureq->req = usb_ep_alloc_request(video->ep, GFP_KERNEL);
if (ureq->req == NULL)
goto error;
list_add_tail(&video->ureq[i].req->list, &video->req_free);
ureq->req->buf = ureq->req_buffer;
ureq->req->length = 0;
ureq->req->complete = uvc_video_complete;
ureq->req->context = ureq;
ureq->video = video;
ureq->last_buf = NULL;
list_add_tail(&ureq->req->list, &video->req_free);
/* req_size/PAGE_SIZE + 1 for overruns and + 1 for header */
sg_alloc_table(&video->ureq[i].sgt,
sg_alloc_table(&ureq->sgt,
DIV_ROUND_UP(req_size - UVCG_REQUEST_HEADER_LEN,
PAGE_SIZE) + 2, GFP_KERNEL);
}
@ -489,8 +497,8 @@ static void uvcg_video_pump(struct work_struct *work)
*/
int uvcg_video_enable(struct uvc_video *video, int enable)
{
unsigned int i;
int ret;
struct uvc_request *ureq;
if (video->ep == NULL) {
uvcg_info(&video->uvc->func,
@ -502,9 +510,10 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
cancel_work_sync(&video->pump);
uvcg_queue_cancel(&video->queue, 0);
for (i = 0; i < video->uvc_num_requests; ++i)
if (video->ureq && video->ureq[i].req)
usb_ep_dequeue(video->ep, video->ureq[i].req);
list_for_each_entry(ureq, &video->ureqs, list) {
if (ureq->req)
usb_ep_dequeue(video->ep, ureq->req);
}
uvc_video_free_requests(video);
uvcg_queue_enable(&video->queue, 0);
@ -536,6 +545,7 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
*/
int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
{
INIT_LIST_HEAD(&video->ureqs);
INIT_LIST_HEAD(&video->req_free);
spin_lock_init(&video->req_lock);
INIT_WORK(&video->pump, uvcg_video_pump);