From patchwork Mon Nov 30 20:34:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jack Pham X-Patchwork-Id: 11941299 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBF7DC63777 for ; Mon, 30 Nov 2020 20:35:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 848662073C for ; Mon, 30 Nov 2020 20:35:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="Xpa2UO69" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729250AbgK3Ufc (ORCPT ); Mon, 30 Nov 2020 15:35:32 -0500 Received: from m42-4.mailgun.net ([69.72.42.4]:52635 "EHLO m42-4.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726716AbgK3Ufc (ORCPT ); Mon, 30 Nov 2020 15:35:32 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1606768506; h=Content-Transfer-Encoding: MIME-Version: Message-Id: Date: Subject: Cc: To: From: Sender; bh=r4LK1+iLv+Ptnfnd1qdCMafEKs/cmIojnQ0/6LFEBtE=; b=Xpa2UO69/WdO475vKP5yBUpaGGcM9vFle/naaUCr7l0OEc9WnnsoZe7nYTVO9BtHE/6fTU0y Jg5oeDwDg7k71Gv9CQXzHduH+oFj+Th2GPi674+94EZgcuaGIVdrnOC3dvpCW9CG9j8p6wUn bsu4p9GvLH6i6Xrd4ESLgcrq4Y4= X-Mailgun-Sending-Ip: 69.72.42.4 X-Mailgun-Sid: WyIxZTE2YSIsICJsaW51eC11c2JAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n10.prod.us-east-1.postgun.com with SMTP id 5fc5577991ec4b75c27be7a1 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 30 Nov 2020 20:35:05 GMT Sender: jackp=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 2248FC43462; Mon, 30 Nov 2020 20:35:05 +0000 (UTC) Received: from jackp-linux.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: jackp) by smtp.codeaurora.org (Postfix) with ESMTPSA id 102B8C433ED; Mon, 30 Nov 2020 20:35:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 102B8C433ED Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=jackp@codeaurora.org From: Jack Pham To: Felipe Balbi , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, Vamsi Krishna Samavedam , Jack Pham Subject: [PATCH] usb: gadget: f_fs: Use local copy of descriptors for userspace copy Date: Mon, 30 Nov 2020 12:34:53 -0800 Message-Id: <20201130203453.28154-1-jackp@codeaurora.org> X-Mailer: git-send-email 2.24.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vamsi Krishna Samavedam The function may be unbound causing the ffs_ep and its descriptors to be freed while userspace is in the middle of an ioctl requesting the same descriptors. Avoid dangling pointer reference by first making a local copy of desctiptors before releasing the spinlock. Fixes: c559a3534109 ("usb: gadget: f_fs: add ioctl returning ep descriptor") Signed-off-by: Vamsi Krishna Samavedam Signed-off-by: Jack Pham Reviewed-by: Peter Chen --- drivers/usb/gadget/function/f_fs.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 046f770a76da..c727cb5de871 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1324,7 +1324,7 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code, case FUNCTIONFS_ENDPOINT_DESC: { int desc_idx; - struct usb_endpoint_descriptor *desc; + struct usb_endpoint_descriptor desc1, *desc; switch (epfile->ffs->gadget->speed) { case USB_SPEED_SUPER: @@ -1336,10 +1336,12 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code, default: desc_idx = 0; } + desc = epfile->ep->descs[desc_idx]; + memcpy(&desc1, desc, desc->bLength); spin_unlock_irq(&epfile->ffs->eps_lock); - ret = copy_to_user((void __user *)value, desc, desc->bLength); + ret = copy_to_user((void __user *)value, &desc1, desc1.bLength); if (ret) ret = -EFAULT; return ret;