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[2620:137:e000::1:20]) by mx.google.com with ESMTP id d4-20020a17090a628400b0023d1e6ae33csi5137237pjj.56.2023.03.16.11.16.55; Thu, 16 Mar 2023 11:17:07 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@163.com header.s=s110527 header.b=LozOv5d0; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=163.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230451AbjCPSJs (ORCPT + 99 others); Thu, 16 Mar 2023 14:09:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58080 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230422AbjCPSJo (ORCPT ); Thu, 16 Mar 2023 14:09:44 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.215]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id A113FC2D9A; Thu, 16 Mar 2023 11:09:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=tAY3k QXbHHXMa0A4+ZTt0dWYBtBAU/Xp4REesuuaIoM=; b=LozOv5d02dvwn333iRz3i K+l873KtPvCm1vLy7jXX3UPjJlnovid8bRgK2vBs1wvr8q+5/FCW4O/pskF0wpdE Jh+bHKpWiMk/MT4IJnGGJDgCduHcY1aaOD8wr6NXIyY+lNu+5gfRIL4OPsaTnqC0 as3jEN9DllrAnUxVKZCB6o= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g2-1 (Coremail) with SMTP id _____wAXLgY3WxNkWY8cAQ--.15896S2; Fri, 17 Mar 2023 02:08:55 +0800 (CST) From: Zheng Wang To: gregkh@linuxfoundation.org Cc: skhan@linuxfoundation.org, p.zabel@pengutronix.de, biju.das.jz@bp.renesas.com, phil.edworthy@renesas.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, hackerzheng666@gmail.com, 1395428693sheep@gmail.com, alex000young@gmail.com, yoshihiro.shimoda.uh@renesas.com, Zheng Wang Subject: [PATCH v7] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition Date: Fri, 17 Mar 2023 02:08:50 +0800 Message-Id: <20230316180850.1600867-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-CM-TRANSID: _____wAXLgY3WxNkWY8cAQ--.15896S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7Zr45Xr15Jr4rCF4UXr4DXFb_yoW8Zr1fpF ZrKFW5Ar4rJFWqq3y7GFykZF1rCF9rKryUZFWxKw48uF1rW3y8JryIqa1UCFnrJFZ3AF4F q3WDu34jqa47u37anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0ziS1v3UUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiXRk0U1WBo8PfvAAAs0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1760549140354915770?= X-GMAIL-MSGID: =?utf-8?q?1760549276991036315?= In renesas_usb3_probe, role_work is bound with renesas_usb3_role_work. renesas_usb3_start will be called to start the work. If we remove the driver which will call usbhs_remove, there may be an unfinished work. The possible sequence is as follows: Fix it by canceling the work before cleanup in the renesas_usb3_remove. Note that removing a driver is a root-only operation, and should never happen. CPU0 CPU1 | renesas_usb3_role_work renesas_usb3_remove | usb_role_switch_unregister| device_unregister | kfree(sw) | free usb3->role_sw | | usb_role_switch_set_role | //use usb3->role_sw This bug was found by static analysis. Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch") Signed-off-by: Zheng Wang Reviewed-by: Yoshihiro Shimoda --- v7: - add more details about how the bug was found suggested by Shuah v6: - beautify the format and add note suggested by Greg KH v5: - fix typo v4: - add Reviewed-by label and resubmit v4 suggested by Greg KH v3: - modify the commit message to make it clearer suggested by Yoshihiro Shimoda v2: - fix typo, use clearer commit message and only cancel the UAF-related work suggested by Yoshihiro Shimoda --- drivers/usb/gadget/udc/renesas_usb3.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c index bee6bceafc4f..a301af66bd91 100644 --- a/drivers/usb/gadget/udc/renesas_usb3.c +++ b/drivers/usb/gadget/udc/renesas_usb3.c @@ -2661,6 +2661,7 @@ static int renesas_usb3_remove(struct platform_device *pdev) debugfs_remove_recursive(usb3->dentry); device_remove_file(&pdev->dev, &dev_attr_role); + cancel_work_sync(&usb3->role_work); usb_role_switch_unregister(usb3->role_sw); usb_del_gadget_udc(&usb3->gadget);