From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033024AbeE1KTv (ORCPT ); Mon, 28 May 2018 06:19:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:39630 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032988AbeE1KTr (ORCPT ); Mon, 28 May 2018 06:19:47 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Malone , Mathieu Malaterre , Bartlomiej Zolnierkiewicz , Sasha Levin Subject: [PATCH 4.4 129/268] fbdev: Fixing arbitrary kernel leak in case FBIOGETCMAP_SPARC in sbusfb_ioctl_helper(). Date: Mon, 28 May 2018 12:01:43 +0200 Message-Id: <20180528100216.702176008@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180528100202.045206534@linuxfoundation.org> References: <20180528100202.045206534@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Malone [ Upstream commit 250c6c49e3b68756b14983c076183568636e2bde ] Fixing arbitrary kernel leak in case FBIOGETCMAP_SPARC in sbusfb_ioctl_helper(). 'index' is defined as an int in sbusfb_ioctl_helper(). We retrieve this from the user: if (get_user(index, &c->index) || __get_user(count, &c->count) || __get_user(ured, &c->red) || __get_user(ugreen, &c->green) || __get_user(ublue, &c->blue)) return -EFAULT; and then we use 'index' in the following way: red = cmap->red[index + i] >> 8; green = cmap->green[index + i] >> 8; blue = cmap->blue[index + i] >> 8; This is a classic information leak vulnerability. 'index' should be an unsigned int, given its usage above. This patch is straight-forward; it changes 'index' to unsigned int in two switch-cases: FBIOGETCMAP_SPARC && FBIOPUTCMAP_SPARC. This patch fixes CVE-2018-6412. Signed-off-by: Peter Malone Acked-by: Mathieu Malaterre Signed-off-by: Bartlomiej Zolnierkiewicz Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/sbuslib.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/video/fbdev/sbuslib.c +++ b/drivers/video/fbdev/sbuslib.c @@ -121,7 +121,7 @@ int sbusfb_ioctl_helper(unsigned long cm unsigned char __user *ured; unsigned char __user *ugreen; unsigned char __user *ublue; - int index, count, i; + unsigned int index, count, i; if (get_user(index, &c->index) || __get_user(count, &c->count) || @@ -160,7 +160,7 @@ int sbusfb_ioctl_helper(unsigned long cm unsigned char __user *ugreen; unsigned char __user *ublue; struct fb_cmap *cmap = &info->cmap; - int index, count, i; + unsigned int index, count, i; u8 red, green, blue; if (get_user(index, &c->index) ||