From patchwork Tue Nov 22 12:35:21 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Keeping X-Patchwork-Id: 13052307 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC567C4332F for ; Tue, 22 Nov 2022 12:35:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233768AbiKVMfi (ORCPT ); Tue, 22 Nov 2022 07:35:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233373AbiKVMff (ORCPT ); Tue, 22 Nov 2022 07:35:35 -0500 Received: from metanate.com (unknown [IPv6:2001:8b0:1628:5005::111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05B685B5B9; Tue, 22 Nov 2022 04:35:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=metanate.com; s=stronger; h=Content-Transfer-Encoding:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Content-Type:Reply-To: Content-ID:Content-Description; bh=klbTl7HLzDhjQhMufy4j3EDYOzLDgfBHxVxD7HUlLtI=; b=Ui9NMrKSmj3G1KD2ytqNoQyqr+ roZDBgCP3u/jG7M04BgVFd571+TCxoRxVgeK6jTAkXvMsPs7ptAx7Yf8RBdzbOh8T5J1He4JtCruI FkM8P+oIK5QiE1/KQZiqorp749Y0ECFETRrjYhXIbEm4dPWPGcRn2nC2c+CVH/w3x5eI9h/GuUtVu xuxTvRSu/84JoykrJADD+worDk5/YOqThfOP0pqYmJUWZwa3FP5EbW3n62oKI8keKhkRVRmycH4X/ 42bJVgWJQaRMv/U9s/rzhSsPhpqfdih4b1k6ImQKbmZOgOsCUeGHi0RjoOPBxUd+gni9A9CApYyMf nZPvgGIQ==; Received: from [81.174.171.191] (helo=donbot.metanate.com) by email.metanate.com with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1oxSUt-0003da-7C; Tue, 22 Nov 2022 12:35:31 +0000 From: John Keeping To: linux-usb@vger.kernel.org Cc: Fabien Chouteau , Peter Korsgaard , Felipe Balbi , Andrzej Pietrasiewicz , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , John Keeping , Lee Jones , Alan Stern Subject: [PATCH 1/3] usb: gadget: f_hid: fix f_hidg lifetime vs cdev Date: Tue, 22 Nov 2022 12:35:21 +0000 Message-Id: <20221122123523.3068034-2-john@metanate.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221122123523.3068034-1-john@metanate.com> References: <20221122123523.3068034-1-john@metanate.com> MIME-Version: 1.0 X-Authenticated: YES Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org The embedded struct cdev does not have its lifetime correctly tied to the enclosing struct f_hidg, so there is a use-after-free if /dev/hidgN is held open while the gadget is deleted. This can readily be replicated with libusbgx's example programs (for conciseness - operating directly via configfs is equivalent): gadget-hid exec 3<> /dev/hidg0 gadget-vid-pid-remove exec 3<&- Pull the existing device up in to struct f_hidg and make use of the cdev_device_{add,del}() helpers. This changes the lifetime of the device object to match struct f_hidg, but note that it is still added and deleted at the same time. Fixes: 71adf1189469 ("USB: gadget: add HID gadget driver") Signed-off-by: John Keeping Reviewed-by: Andrzej Pietrasiewicz --- drivers/usb/gadget/function/f_hid.c | 52 ++++++++++++++++------------- 1 file changed, 28 insertions(+), 24 deletions(-) diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c index ca0a7d9eaa34..8b8bbeaa27cb 100644 --- a/drivers/usb/gadget/function/f_hid.c +++ b/drivers/usb/gadget/function/f_hid.c @@ -71,7 +71,7 @@ struct f_hidg { wait_queue_head_t write_queue; struct usb_request *req; - int minor; + struct device dev; struct cdev cdev; struct usb_function func; @@ -84,6 +84,14 @@ static inline struct f_hidg *func_to_hidg(struct usb_function *f) return container_of(f, struct f_hidg, func); } +static void hidg_release(struct device *dev) +{ + struct f_hidg *hidg = container_of(dev, struct f_hidg, dev); + + kfree(hidg->set_report_buf); + kfree(hidg); +} + /*-------------------------------------------------------------------------*/ /* Static descriptors */ @@ -904,9 +912,7 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f) struct usb_ep *ep; struct f_hidg *hidg = func_to_hidg(f); struct usb_string *us; - struct device *device; int status; - dev_t dev; /* maybe allocate device-global string IDs, and patch descriptors */ us = usb_gstrings_attach(c->cdev, ct_func_strings, @@ -999,21 +1005,11 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f) /* create char device */ cdev_init(&hidg->cdev, &f_hidg_fops); - dev = MKDEV(major, hidg->minor); - status = cdev_add(&hidg->cdev, dev, 1); + status = cdev_device_add(&hidg->cdev, &hidg->dev); if (status) goto fail_free_descs; - device = device_create(hidg_class, NULL, dev, NULL, - "%s%d", "hidg", hidg->minor); - if (IS_ERR(device)) { - status = PTR_ERR(device); - goto del; - } - return 0; -del: - cdev_del(&hidg->cdev); fail_free_descs: usb_free_all_descriptors(f); fail: @@ -1244,9 +1240,7 @@ static void hidg_free(struct usb_function *f) hidg = func_to_hidg(f); opts = container_of(f->fi, struct f_hid_opts, func_inst); - kfree(hidg->report_desc); - kfree(hidg->set_report_buf); - kfree(hidg); + put_device(&hidg->dev); mutex_lock(&opts->lock); --opts->refcnt; mutex_unlock(&opts->lock); @@ -1256,8 +1250,7 @@ static void hidg_unbind(struct usb_configuration *c, struct usb_function *f) { struct f_hidg *hidg = func_to_hidg(f); - device_destroy(hidg_class, MKDEV(major, hidg->minor)); - cdev_del(&hidg->cdev); + cdev_device_del(&hidg->cdev, &hidg->dev); usb_free_all_descriptors(f); } @@ -1266,6 +1259,7 @@ static struct usb_function *hidg_alloc(struct usb_function_instance *fi) { struct f_hidg *hidg; struct f_hid_opts *opts; + int ret; /* allocate and initialize one new instance */ hidg = kzalloc(sizeof(*hidg), GFP_KERNEL); @@ -1277,17 +1271,27 @@ static struct usb_function *hidg_alloc(struct usb_function_instance *fi) mutex_lock(&opts->lock); ++opts->refcnt; - hidg->minor = opts->minor; + device_initialize(&hidg->dev); + hidg->dev.release = hidg_release; + hidg->dev.class = hidg_class; + hidg->dev.devt = MKDEV(major, opts->minor); + ret = dev_set_name(&hidg->dev, "hidg%d", opts->minor); + if (ret) { + --opts->refcnt; + mutex_unlock(&opts->lock); + return ERR_PTR(ret); + } + hidg->bInterfaceSubClass = opts->subclass; hidg->bInterfaceProtocol = opts->protocol; hidg->report_length = opts->report_length; hidg->report_desc_length = opts->report_desc_length; if (opts->report_desc) { - hidg->report_desc = kmemdup(opts->report_desc, - opts->report_desc_length, - GFP_KERNEL); + hidg->report_desc = devm_kmemdup(&hidg->dev, opts->report_desc, + opts->report_desc_length, + GFP_KERNEL); if (!hidg->report_desc) { - kfree(hidg); + put_device(&hidg->dev); mutex_unlock(&opts->lock); return ERR_PTR(-ENOMEM); }