Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754579Ab0KNJZl (ORCPT ); Sun, 14 Nov 2010 04:25:41 -0500 Received: from mail-ew0-f46.google.com ([209.85.215.46]:33302 "EHLO mail-ew0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754179Ab0KNJZj (ORCPT ); Sun, 14 Nov 2010 04:25:39 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=WcSRjRm/Mp+RiSAIlImivWP3tWPyTmMOJK2wFygLKHu6HW8+tReslxN3Say4JGUjVt BkUV4d3OfyegXZTnzmO+UsKdzSYtSCIUePDc9pJEWQVSC/YvgnB4im1YM8NhrCqCuw1L vq73gMesucVwg/FnqplhOXLtUof1kcdY2vxVg= Date: Sun, 14 Nov 2010 12:25:33 +0300 From: Vasiliy Kulikov To: Andreas Dilger Cc: Andrew Morton , kernel-janitors@vger.kernel.org, Alexander Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] fs: select: fix information leak to userspace Message-ID: <20101114092533.GB5323@albatros> References: <1289421483-23907-1-git-send-email-segooon@gmail.com> <20101112120834.33062900.akpm@linux-foundation.org> <8D90F8B2-EA29-4EB9-9807-294CE0D5523B@dilger.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8D90F8B2-EA29-4EB9-9807-294CE0D5523B@dilger.ca> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1434 Lines: 46 On some architectures __kernel_suseconds_t is int. On these archs struct timeval has padding bytes at the end. This struct is copied to userspace with these padding bytes uninitialized. This leads to leaking of contents of kernel stack memory. Signed-off-by: Vasiliy Kulikov --- Patch v1 used memset(), it was waste of cycles on almost all archs. Compile tested. fs/select.c | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/select.c b/fs/select.c index b7b10aa..43d4805 100644 --- a/fs/select.c +++ b/fs/select.c @@ -288,7 +288,6 @@ static int poll_select_copy_remaining(struct timespec *end_time, void __user *p, int timeval, int ret) { struct timespec rts; - struct timeval rtv; if (!p) return ret; @@ -306,8 +305,10 @@ static int poll_select_copy_remaining(struct timespec *end_time, void __user *p, rts.tv_sec = rts.tv_nsec = 0; if (timeval) { - rtv.tv_sec = rts.tv_sec; - rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; + struct timeval rtv = { + .tv_sec = rts.tv_sec, + .tv_usec = rts.tv_nsec / NSEC_PER_USEC + }; if (!copy_to_user(p, &rtv, sizeof(rtv))) return ret; -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/