From patchwork Tue Oct 3 23:18:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Avichal Rakesh X-Patchwork-Id: 729217 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 317F93F4D0 for ; Tue, 3 Oct 2023 23:19:12 +0000 (UTC) Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 132AC10E for ; Tue, 3 Oct 2023 16:19:02 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-d852a6749bcso1801542276.0 for ; Tue, 03 Oct 2023 16:19:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1696375141; x=1696979941; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=ArVoPjwYMHkkpCMoH+/iCkmQnlykQeUcYYwAmxq8LD0=; b=WydiE7B3N+hxLrGCWv4r4W2+Hd07tS0rkcgTxOlIh7Keo6dQK21MkUankHbAc5gPHM yTxnTiLLsGXswPhpSHpS4YGFvuedVq451ocS1KZjVmrC7j5gvw/425UlojvMTGzg0/xs Et8+UBWiGq+zV+6OH4AWSd+E8Y7xruiXGkS3mF5N7ZY3cNFxBdoPqMZB1ccMvQoEeRfe LCykC8MARovqNllAv5cOU1+7CxbaH8w1h1uUV/K2NWXrKJVQ2JSPRnWWYhx1rRa1dQm8 jlyR3VFClwnKlS+OUqXzxL/RkXpdMiYDulE86FaODXDFtPpYxjbCyI+nqJyfbZV9uOh9 ln7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696375141; x=1696979941; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=ArVoPjwYMHkkpCMoH+/iCkmQnlykQeUcYYwAmxq8LD0=; b=vescC4jBSkgl81XRREkgDxCtKpktk3RUlLsnfZ/kaUaAjUFRJ9hQ3h4Kxt7wllDFbV LhSz5zfwbcIF3IwZIObHFPMtiIHXnx/azzX3lgozpRmm7mjL7eXvyp5q9zPoI1VeozLf p0oop8yK6wx00riaPl+mWVOf+9L/ggO4l7Qn9MsN4oeEp2yXEyw8CXi6WebqyJkZI/I/ KKaFLXpfeHXwwvivb7W4w3jdgiRfBRjXJLAG2qR87p/b7sgk2vaENjUsE4ozPbt5CnAp xt9GCroPoWKOIx0xyypS908TABruADGx8WWhlT5LNeLVyHIxBfUqg4vAIYTvm92bX0WN yjbg== X-Gm-Message-State: AOJu0YxYjtsTGbp5Y7V3YjiLmJHk5/i18M5UHUlWGJHoi9QFBVGxXmPO rJ3O9ja6ToRqx++RTw+GwF7x9NljMgwj X-Google-Smtp-Source: AGHT+IFSGzebqILp0IStIPy/7RKYqInAfboPET5jE6hqmI9IOEaPOwoqZFGZGSwEg2T7/Xb7Encqp+EjDHJG X-Received: from hi-h2o-specialist.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:3cef]) (user=arakesh job=sendgmr) by 2002:a25:f816:0:b0:d84:e73f:6f8c with SMTP id u22-20020a25f816000000b00d84e73f6f8cmr9891ybd.6.1696375141136; Tue, 03 Oct 2023 16:19:01 -0700 (PDT) Date: Tue, 3 Oct 2023 16:18:56 -0700 In-Reply-To: <20230930184821.310143-2-arakesh@google.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20230930184821.310143-2-arakesh@google.com> X-Mailer: git-send-email 2.42.0.582.g8ccd20d70d-goog Message-ID: <20231003231856.2591708-1-arakesh@google.com> Subject: [PATCH v2 1/3] usb: gadget: uvc: prevent use of disabled endpoint From: Avichal Rakesh To: arakesh@google.com, dan.scally@ideasonboard.com, gregkh@linuxfoundation.org, laurent.pinchart@ideasonboard.com, mgr@pengutronix.de Cc: etalvala@google.com, jchowdhary@google.com, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Currently the set_alt callback immediately disables the endpoint and queues the v4l2 streamoff event. However, as the streamoff event is processed asynchronously, it is possible that the video_pump thread attempts to queue requests to an already disabled endpoint. This change moves disabling usb endpoint to the end of streamoff event callback. To be consistent with the actual streaming state, uvc->state is now toggled between CONNECTED and STREAMING from the v4l2 event callback only. Link: https://lore.kernel.org/20230615171558.GK741@pendragon.ideasonboard.com/ Link: https://lore.kernel.org/20230531085544.253363-1-dan.scally@ideasonboard.com/ Signed-off-by: Avichal Rakesh --- v1 -> v2: Rebased to ToT and reworded commit message. drivers/usb/gadget/function/f_uvc.c | 11 +++++------ drivers/usb/gadget/function/f_uvc.h | 2 +- drivers/usb/gadget/function/uvc.h | 2 +- drivers/usb/gadget/function/uvc_v4l2.c | 21 ++++++++++++++++++--- 4 files changed, 25 insertions(+), 11 deletions(-) -- 2.42.0.582.g8ccd20d70d-goog diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c index faa398109431..75c9f9a3f884 100644 --- a/drivers/usb/gadget/function/f_uvc.c +++ b/drivers/usb/gadget/function/f_uvc.c @@ -263,10 +263,13 @@ uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl) return 0; } -void uvc_function_setup_continue(struct uvc_device *uvc) +void uvc_function_setup_continue(struct uvc_device *uvc, int disable_ep) { struct usb_composite_dev *cdev = uvc->func.config->cdev; + if (disable_ep && uvc->video.ep) { + usb_ep_disable(uvc->video.ep); + } usb_composite_setup_continue(cdev); } @@ -337,15 +340,11 @@ uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt) if (uvc->state != UVC_STATE_STREAMING) return 0; - if (uvc->video.ep) - usb_ep_disable(uvc->video.ep); - memset(&v4l2_event, 0, sizeof(v4l2_event)); v4l2_event.type = UVC_EVENT_STREAMOFF; v4l2_event_queue(&uvc->vdev, &v4l2_event); - uvc->state = UVC_STATE_CONNECTED; - return 0; + return USB_GADGET_DELAYED_STATUS; case 1: if (uvc->state != UVC_STATE_CONNECTED) diff --git a/drivers/usb/gadget/function/f_uvc.h b/drivers/usb/gadget/function/f_uvc.h index 1db972d4beeb..e7f9f13f14dc 100644 --- a/drivers/usb/gadget/function/f_uvc.h +++ b/drivers/usb/gadget/function/f_uvc.h @@ -11,7 +11,7 @@ struct uvc_device; -void uvc_function_setup_continue(struct uvc_device *uvc); +void uvc_function_setup_continue(struct uvc_device *uvc, int disale_ep); void uvc_function_connect(struct uvc_device *uvc); diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h index 6751de8b63ad..989bc6b4e93d 100644 --- a/drivers/usb/gadget/function/uvc.h +++ b/drivers/usb/gadget/function/uvc.h @@ -177,7 +177,7 @@ struct uvc_file_handle { * Functions */ -extern void uvc_function_setup_continue(struct uvc_device *uvc); +extern void uvc_function_setup_continue(struct uvc_device *uvc, int disable_ep); extern void uvc_function_connect(struct uvc_device *uvc); extern void uvc_function_disconnect(struct uvc_device *uvc); diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c index 3f0a9795c0d4..3d3469883ed0 100644 --- a/drivers/usb/gadget/function/uvc_v4l2.c +++ b/drivers/usb/gadget/function/uvc_v4l2.c @@ -451,7 +451,7 @@ uvc_v4l2_streamon(struct file *file, void *fh, enum v4l2_buf_type type) * Complete the alternate setting selection setup phase now that * userspace is ready to provide video frames. */ - uvc_function_setup_continue(uvc); + uvc_function_setup_continue(uvc, 0); uvc->state = UVC_STATE_STREAMING; return 0; @@ -463,11 +463,19 @@ uvc_v4l2_streamoff(struct file *file, void *fh, enum v4l2_buf_type type) struct video_device *vdev = video_devdata(file); struct uvc_device *uvc = video_get_drvdata(vdev); struct uvc_video *video = &uvc->video; + int ret = 0; if (type != video->queue.queue.type) return -EINVAL; - return uvcg_video_enable(video, 0); + uvc->state = UVC_STATE_CONNECTED; + ret = uvcg_video_enable(video, 0); + if (ret < 0) { + return ret; + } + + uvc_function_setup_continue(uvc, 1); + return 0; } static int @@ -500,6 +508,14 @@ uvc_v4l2_subscribe_event(struct v4l2_fh *fh, static void uvc_v4l2_disable(struct uvc_device *uvc) { uvc_function_disconnect(uvc); + if (uvc->state == UVC_STATE_STREAMING) { + /* + * Drop uvc->state to CONNECTED if it was streaming before. + * This ensures that the usb_requests are no longer queued + * to the controller. + */ + uvc->state = UVC_STATE_CONNECTED; + } uvcg_video_enable(&uvc->video, 0); uvcg_free_buffers(&uvc->video.queue); uvc->func_connected = false; @@ -647,4 +663,3 @@ const struct v4l2_file_operations uvc_v4l2_fops = { .get_unmapped_area = uvcg_v4l2_get_unmapped_area, #endif }; - From patchwork Tue Oct 3 23:21:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Avichal Rakesh X-Patchwork-Id: 729216 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DAFBE3FB04 for ; Tue, 3 Oct 2023 23:21:26 +0000 (UTC) Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C11E3B0 for ; Tue, 3 Oct 2023 16:21:23 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-5a1df5b7830so21518867b3.1 for ; Tue, 03 Oct 2023 16:21:23 -0700 (PDT) DKIM-Signature: v=1; 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Tue, 03 Oct 2023 16:21:23 -0700 (PDT) Date: Tue, 3 Oct 2023 16:21:20 -0700 In-Reply-To: <20230930184821.310143-4-arakesh@google.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20230930184821.310143-4-arakesh@google.com> X-Mailer: git-send-email 2.42.0.582.g8ccd20d70d-goog Message-ID: <20231003232120.2594176-1-arakesh@google.com> Subject: [PATCH v2 3/3] usb: gadget: uvc: Fix use-after-free for inflight usb_requests From: Avichal Rakesh To: arakesh@google.com, dan.scally@ideasonboard.com, gregkh@linuxfoundation.org, laurent.pinchart@ideasonboard.com, m.grzeschik@pengutronix.de, mgr@pengutronix.de Cc: etalvala@google.com, jchowdhary@google.com, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net 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 is patch 2 of 2 in fixing the use-after-free issue. It adds a new flag to uvc_request to mark it as 'abandoned'. When disabling the video stream, instead of de-allocating all uvc_requests and usb_requests, the gadget driver only de-allocates those usb_requests that are currently owned by the gadget driver (as present in req_free). Other usb_requests have their corresponding 'is_abandoned' flag tripped, and the usb_requests complete handler takes care of freeing the usb_request and its corresponding uvc_request. This should ensure that uvc gadget driver never accidentally de-allocates a usb_request that it doesn't own. Link: https://lore.kernel.org/7cd81649-2795-45b6-8c10-b7df1055020d@google.com Suggested-by: Michael Grzeschik Signed-off-by: Avichal Rakesh --- v1 -> v2: Rebased to ToT, and fixed deadlock reported in https://lore.kernel.org/all/ZRv2UnKztgyqk2pt@pengutronix.de/ drivers/usb/gadget/function/uvc.h | 1 + drivers/usb/gadget/function/uvc_video.c | 118 ++++++++++++++++++++---- 2 files changed, 102 insertions(+), 17 deletions(-) -- 2.42.0.582.g8ccd20d70d-goog diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h index 993694da0bbc..e69cfb7cced1 100644 --- a/drivers/usb/gadget/function/uvc.h +++ b/drivers/usb/gadget/function/uvc.h @@ -82,6 +82,7 @@ struct uvc_request { u8 header[UVCG_REQUEST_HEADER_LEN]; struct uvc_buffer *last_buf; struct list_head list; + bool is_abandoned; }; struct uvc_video { diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c index 3c4d286d81c0..69521886d599 100644 --- a/drivers/usb/gadget/function/uvc_video.c +++ b/drivers/usb/gadget/function/uvc_video.c @@ -271,7 +271,21 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req) struct uvc_video *video = ureq->video; struct uvc_video_queue *queue = &video->queue; struct uvc_device *uvc = video->uvc; + struct uvc_buffer *last_buf; unsigned long flags; + bool is_abandoned; + + spin_lock_irqsave(&video->req_lock, flags); + is_abandoned = ureq->is_abandoned; + last_buf = ureq->last_buf; + ureq->last_buf = NULL; + spin_unlock_irqrestore(&video->req_lock, flags); + + if (is_abandoned) { + uvcg_dbg(&video->uvc->func, "Freeing abandoned usb_request\n"); + uvc_video_free_request(ureq, ep); + return; + } if (uvc->state == UVC_STATE_CONNECTED) { usb_ep_free_request(video->ep, ureq->req); @@ -300,15 +314,29 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req) uvcg_queue_cancel(queue, 0); } - if (ureq->last_buf) { - uvcg_complete_buffer(&video->queue, ureq->last_buf); - ureq->last_buf = NULL; + if (last_buf) { + spin_lock_irqsave(&video->queue.irqlock, flags); + uvcg_complete_buffer(&video->queue, last_buf); + spin_unlock_irqrestore(&video->queue.irqlock, flags); } + /* + * request might have been abandoned while being processed. + * do a last minute check before queueing the request back. + */ spin_lock_irqsave(&video->req_lock, flags); - list_add_tail(&req->list, &video->req_free); + is_abandoned = ureq->is_abandoned; + if (!is_abandoned) + list_add_tail(&req->list, &video->req_free); spin_unlock_irqrestore(&video->req_lock, flags); + if (is_abandoned) { + uvcg_dbg(&video->uvc->func, + "usb_request abandoned mid-processing - freeing.\n"); + uvc_video_free_request(ureq, ep); + return; + } + if (uvc->state == UVC_STATE_STREAMING) queue_work(video->async_wq, &video->pump); } @@ -372,7 +400,6 @@ uvc_video_alloc_requests(struct uvc_video *video) } video->req_size = req_size; - return 0; error: @@ -504,13 +531,80 @@ static void uvcg_video_pump(struct work_struct *work) return; } +/* + * Disable video stream. This ensures that any inflight usb requests are marked + * for clean up and all video buffers are dropped before returning. + */ +static void uvcg_video_disable(struct uvc_video *video) +{ + struct uvc_buffer *buf, *tmp_buf; + struct uvc_request *ureq, *temp; + struct list_head buf_list; /* track in-flight video buffers */ + struct usb_request *req; + unsigned long flags; + + INIT_LIST_HEAD(&buf_list); + + cancel_work_sync(&video->pump); + uvcg_queue_cancel(&video->queue, 0); + + list_for_each_entry(ureq, &video->ureqs, list) { + if (ureq->req) + usb_ep_dequeue(video->ep, ureq->req); + } + + /** + * acquiring req_lock here should prevent any more complete + * callbacks from processing until we've abandoned the + * requests that are still in-flight and let the complete + * callback handle cleanup + */ + spin_lock_irqsave(&video->req_lock, flags); + /* abandon all usb requests */ + list_for_each_entry_safe(ureq, temp, &video->ureqs, list) { + ureq->is_abandoned = true; + if (ureq->last_buf) { + list_add(&ureq->last_buf->queue, &buf_list); + ureq->last_buf = NULL; + } + list_del_init(&ureq->list); + } + /* + * re-add uvc_requests currently owned by the gadget to + * video->ureqs to be deallocated. This effectively leaves + * video->ureqs with the requests that we currently own. + */ + list_for_each_entry(req, &video->req_free, list) { + ureq = req->context; + list_add_tail(&ureq->list, &video->ureqs); + } + spin_unlock_irqrestore(&video->req_lock, flags); + + /* + * drop abandoned uvc_buffers, as the completion handler + * no longer will + */ + if (!list_empty(&buf_list)) { + spin_lock_irqsave(&video->queue.irqlock, flags); + list_for_each_entry_safe(buf, tmp_buf, + &buf_list, queue) { + video->queue.flags |= UVC_QUEUE_DROP_INCOMPLETE; + uvcg_complete_buffer(&video->queue, buf); + list_del(&buf->queue); + } + spin_unlock_irqrestore(&video->queue.irqlock, flags); + } + + uvc_video_free_requests(video); + uvcg_queue_enable(&video->queue, 0); +} + /* * Enable or disable the video stream. */ int uvcg_video_enable(struct uvc_video *video, int enable) { struct uvc_device *uvc = video->uvc; - struct uvc_request *ureq; int ret; if (video->ep == NULL) { @@ -521,17 +615,7 @@ int uvcg_video_enable(struct uvc_video *video, int enable) if (!enable) { uvc->state = UVC_STATE_CONNECTED; - - cancel_work_sync(&video->pump); - uvcg_queue_cancel(&video->queue, 0); - - 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); + uvcg_video_disable(video); return 0; }