| Message ID | 20231012002451.254737-2-arakesh@google.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | None | expand |
A short second review. On Wed, Oct 11, 2023 at 05:24:50PM -0700, 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> >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 > > drivers/usb/gadget/function/uvc.h | 3 +- > drivers/usb/gadget/function/uvc_video.c | 87 ++++++++++++++----------- > 2 files changed, 50 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..b62b3de79153 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; >+ 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 +336,32 @@ 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; Please add an empty line here. >+ INIT_LIST_HEAD(&ureq->list); Please add an empty line here. >+ 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) You could also use if (!ureq->req_buffer) > 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 +496,8 @@ 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 +509,10 @@ 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 +544,7 @@ 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); >-- >2.42.0.609.gbb76f46606-goog > >
On 10/18/23 06:03, Michael Grzeschik wrote: > A short second review. Thank you for the review. Sent out a v5 with the comments addressed! > > On Wed, Oct 11, 2023 at 05:24:50PM -0700, 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> >> 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 >> >> drivers/usb/gadget/function/uvc.h | 3 +- >> drivers/usb/gadget/function/uvc_video.c | 87 ++++++++++++++----------- >> 2 files changed, 50 insertions(+), 40 deletions(-) >> - if (video->ureq[i].req_buffer == NULL) >> + ureq->req_buffer = kmalloc(req_size, GFP_KERNEL); >> + if (ureq->req_buffer == NULL) > You could also use if (!ureq->req_buffer) Keeping this as is because I prefer `== NULL` check for readability. Didn't find any specific rules in the kernel codestyle, so sticking with the more readable option (in my opinion). > >> 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 +496,8 @@ 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 +509,10 @@ 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 +544,7 @@ 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); >> -- >> 2.42.0.609.gbb76f46606-goog >> >> >
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..b62b3de79153 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; + 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 +336,32 @@ 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 +496,8 @@ 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 +509,10 @@ 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 +544,7 @@ 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);