| Message ID | 20231024183605.908253-2-arakesh@google.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v8,1/4] usb: gadget: uvc: prevent use of disabled endpoint | expand |
Hi Avichal - thanks for the patch On 24/10/2023 19:36, Avichal Rakesh wrote: > 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 > Suggested-by: Michael Grzeschik <m.grzeschik@pengutronix.de> > Reviewed-by: Michael Grzeschik <m.grzeschik@pengutronix.de> > Tested-by: Michael Grzeschik <m.grzeschik@pengutronix.de> > Signed-off-by: Avichal Rakesh <arakesh@google.com> > --- > v1 -> v2: Rebased to ToT > v2 -> v3: Fix email threading goof-up > v3 -> v4: Address review comments & re-rebase to ToT > v4 -> v5: Address more review comments. Add Reviewed-by & Tested-by. > v5 -> v6: No change > v6 -> v7: No change > v7 -> v8: No change. Getting back in review queue > > drivers/usb/gadget/function/uvc.h | 3 +- > drivers/usb/gadget/function/uvc_video.c | 89 ++++++++++++++----------- > 2 files changed, 52 insertions(+), 40 deletions(-) > > diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h > index 989bc6b4e93d..993694da0bbc 100644 > --- a/drivers/usb/gadget/function/uvc.h > +++ b/drivers/usb/gadget/function/uvc.h > @@ -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; > > diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c > index c334802ac0a4..c180866c8e34 100644 > --- a/drivers/usb/gadget/function/uvc_video.c > +++ b/drivers/usb/gadget/function/uvc_video.c > @@ -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)) Is this conditional needed? You can only get here through the list_for_each_entry_safe() > + 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; > - > - if (video->ureq) { > - for (i = 0; i < video->uvc_num_requests; ++i) { > - sg_free_table(&video->ureq[i].sgt); > + struct uvc_request *ureq, *temp; > > - 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 +336,34 @@ 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; > + INIT_LIST_HEAD(&video->ureqs); Probably unecessary here; it's done in uvc_video_free_requests() and uvcg_video_init() already > + for (i = 0; i < video->uvc_num_requests; i++) { > + ureq = kzalloc(sizeof(struct uvc_request), GFP_KERNEL); > + if (ureq == NULL) > + goto error; > + > + INIT_LIST_HEAD(&ureq->list); > + > + list_add_tail(&ureq->list, &video->ureqs); > > - 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) > + ureq->req_buffer = kmalloc(req_size, GFP_KERNEL); > + if (ureq->req_buffer == NULL) > goto error; > > - video->ureq[i].req = usb_ep_alloc_request(video->ep, GFP_KERNEL); > - if (video->ureq[i].req == NULL) > + ureq->req = usb_ep_alloc_request(video->ep, GFP_KERNEL); > + if (ureq->req == 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->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(&video->ureq[i].req->list, &video->req_free); > + 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 +498,8 @@ 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 +511,10 @@ 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 +546,7 @@ 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); > -- > 2.42.0.758.gaed0368e0e-goog
Thank you for the reviews, Dan! Uploaded v9 with the comments addressed. On 10/27/23 05:57, Dan Scally wrote: > Hi Avichal - thanks for the patch > > On 24/10/2023 19:36, Avichal Rakesh wrote: >> 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. >> >> <snip> >> >> diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c >> index c334802ac0a4..c180866c8e34 100644 >> --- a/drivers/usb/gadget/function/uvc_video.c >> +++ b/drivers/usb/gadget/function/uvc_video.c >> @@ -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)) > > > Is this conditional needed? You can only get here through the list_for_each_entry_safe() Strictly speaking, we don't need this check right now. As you said, we currently only get to this from within a list_for_each_entry_safe block. However, we end up needing the check in the very next patch. Considering this is a function with no real control over who might call it, it seemed reasonable to write this a little defensively in case of a partial revert of the patchset. > >> + list_del_init(&ureq->list); >> + >> + kfree(ureq); >> +} >> + >> <snip> >> @@ -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 +336,34 @@ 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; >> + INIT_LIST_HEAD(&video->ureqs); > > > Probably unecessary here; it's done in uvc_video_free_requests() and uvcg_video_init() already Ah, that is fair. Added a BUG_ON instead, like we do for video->req_size so we still catch cases where the state might be inconsistent. > >> + for (i = 0; i < video->uvc_num_requests; i++) { >> + ureq = kzalloc(sizeof(struct uvc_request), GFP_KERNEL); >> + if (ureq == NULL) >> + goto error; >> + >> + INIT_LIST_HEAD(&ureq->list); >> + >> + list_add_tail(&ureq->list, &video->ureqs); >> >> <snip> Regards, Avi.
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h index 989bc6b4e93d..993694da0bbc 100644 --- a/drivers/usb/gadget/function/uvc.h +++ b/drivers/usb/gadget/function/uvc.h @@ -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; diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c index c334802ac0a4..c180866c8e34 100644 --- a/drivers/usb/gadget/function/uvc_video.c +++ b/drivers/usb/gadget/function/uvc_video.c @@ -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; - - if (video->ureq) { - for (i = 0; i < video->uvc_num_requests; ++i) { - sg_free_table(&video->ureq[i].sgt); + struct uvc_request *ureq, *temp; - 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 +336,34 @@ 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; + INIT_LIST_HEAD(&video->ureqs); + for (i = 0; i < video->uvc_num_requests; i++) { + ureq = kzalloc(sizeof(struct uvc_request), GFP_KERNEL); + if (ureq == NULL) + goto error; + + INIT_LIST_HEAD(&ureq->list); + + list_add_tail(&ureq->list, &video->ureqs); - 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) + ureq->req_buffer = kmalloc(req_size, GFP_KERNEL); + if (ureq->req_buffer == NULL) goto error; - video->ureq[i].req = usb_ep_alloc_request(video->ep, GFP_KERNEL); - if (video->ureq[i].req == NULL) + ureq->req = usb_ep_alloc_request(video->ep, GFP_KERNEL); + if (ureq->req == 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->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(&video->ureq[i].req->list, &video->req_free); + 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 +498,8 @@ 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 +511,10 @@ 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 +546,7 @@ 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);