From patchwork Sat Jan 6 01:10:32 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 46348 X-Patchwork-Delegate: laurent.pinchart@ideasonboard.com Received: from vger.kernel.org ([209.132.180.67]) by www.linuxtv.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eXdC7-0006BX-DZ; Sat, 06 Jan 2018 01:22:43 +0000 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753769AbeAFBSu (ORCPT + 1 other); Fri, 5 Jan 2018 20:18:50 -0500 Received: from mga05.intel.com ([192.55.52.43]:34280 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753763AbeAFBSr (ORCPT ); Fri, 5 Jan 2018 20:18:47 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Jan 2018 17:18:46 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,320,1511856000"; d="scan'208";a="21819327" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga001.jf.intel.com with ESMTP; 05 Jan 2018 17:18:46 -0800 Subject: [PATCH 07/18] [media] uvcvideo: prevent bounds-check bypass via speculative execution From: Dan Williams To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, alan@linux.intel.com, peterz@infradead.org, netdev@vger.kernel.org, Laurent Pinchart , gregkh@linuxfoundation.org, tglx@linutronix.de, Mauro Carvalho Chehab , torvalds@linux-foundation.org, Elena Reshetova , linux-media@vger.kernel.org Date: Fri, 05 Jan 2018 17:10:32 -0800 Message-ID: <151520103240.32271.14706852449205864676.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151520099201.32271.4677179499894422956.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151520099201.32271.4677179499894422956.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Static analysis reports that 'index' may be a user controlled value that is used as a data dependency to read 'pin' from the 'selector->baSourceID' array. In order to avoid potential leaks of kernel memory values, block speculative execution of the instruction stream that could issue reads based on an invalid value of 'pin'. Based on an original patch by Elena Reshetova. Cc: Laurent Pinchart Cc: Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org Signed-off-by: Elena Reshetova Signed-off-by: Dan Williams Reviewed-by: Laurent Pinchart --- drivers/media/usb/uvc/uvc_v4l2.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c index 3e7e283a44a8..7442626dc20e 100644 --- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -810,6 +811,7 @@ static int uvc_ioctl_enum_input(struct file *file, void *fh, struct uvc_entity *iterm = NULL; u32 index = input->index; int pin = 0; + __u8 *elem; if (selector == NULL || (chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) { @@ -820,8 +822,9 @@ static int uvc_ioctl_enum_input(struct file *file, void *fh, break; } pin = iterm->id; - } else if (index < selector->bNrInPins) { - pin = selector->baSourceID[index]; + } else if ((elem = nospec_array_ptr(selector->baSourceID, index, + selector->bNrInPins))) { + pin = *elem; list_for_each_entry(iterm, &chain->entities, chain) { if (!UVC_ENTITY_IS_ITERM(iterm)) continue;