From mboxrd@z Thu Jan 1 00:00:00 1970 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=-16.7 required=3.0 tests=BAYES_00, 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 004BDC433FE for ; Thu, 10 Dec 2020 19:16:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96FD42388B for ; Thu, 10 Dec 2020 19:16:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390441AbgLJOaq (ORCPT ); Thu, 10 Dec 2020 09:30:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:38072 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390265AbgLJOaK (ORCPT ); Thu, 10 Dec 2020 09:30:10 -0500 From: Greg Kroah-Hartman Authentication-Results: mail.kernel.org; dkim=permerror (bad message/signature format) To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Chen , Vamsi Krishna Samavedam , Jack Pham Subject: [PATCH 4.9 22/45] usb: gadget: f_fs: Use local copy of descriptors for userspace copy Date: Thu, 10 Dec 2020 15:26:36 +0100 Message-Id: <20201210142603.464476420@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201210142602.361598591@linuxfoundation.org> References: <20201210142602.361598591@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vamsi Krishna Samavedam commit a4b98a7512f18534ce33a7e98e49115af59ffa00 upstream. 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") Reviewed-by: Peter Chen Signed-off-by: Vamsi Krishna Samavedam Signed-off-by: Jack Pham Cc: stable Link: https://lore.kernel.org/r/20201130203453.28154-1-jackp@codeaurora.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_fs.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1224,7 +1224,7 @@ static long ffs_epfile_ioctl(struct file 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: @@ -1236,10 +1236,12 @@ static long ffs_epfile_ioctl(struct file 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 *)value, desc, sizeof(*desc)); + ret = copy_to_user((void *)value, &desc1, desc1.bLength); if (ret) ret = -EFAULT; return ret;