Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933326AbeALAzc (ORCPT + 1 other); Thu, 11 Jan 2018 19:55:32 -0500 Received: from mga11.intel.com ([192.55.52.93]:43761 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932148AbeALAz2 (ORCPT ); Thu, 11 Jan 2018 19:55:28 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,346,1511856000"; d="scan'208";a="23373831" Subject: [PATCH v2 09/19] ipv6: prevent bounds-check bypass via speculative execution From: Dan Williams To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, Hideaki YOSHIFUJI , netdev@vger.kernel.org, Alexey Kuznetsov , tglx@linutronix.de, torvalds@linux-foundation.org, "David S. Miller" , Elena Reshetova , alan@linux.intel.com Date: Thu, 11 Jan 2018 16:47:13 -0800 Message-ID: <151571803370.27429.18342496227199960317.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151571798296.27429.7166552848688034184.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151571798296.27429.7166552848688034184.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Static analysis reports that 'offset' may be a user controlled value that is used as a data dependency reading from a raw6_frag_vec buffer. In order to avoid potential leaks of kernel memory values, block speculative execution of the instruction stream that could issue further reads based on an invalid '*(rfv->c + offset)' value. Based on an original patch by Elena Reshetova. Cc: "David S. Miller" Cc: Alexey Kuznetsov Cc: Hideaki YOSHIFUJI Cc: netdev@vger.kernel.org Signed-off-by: Elena Reshetova Signed-off-by: Dan Williams --- net/ipv6/raw.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 761a473a07c5..0b7ceeb6f709 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include @@ -725,17 +726,18 @@ static int raw6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) { struct raw6_frag_vec *rfv = from; + char *rfv_buf; - if (offset < rfv->hlen) { + rfv_buf = array_ptr(rfv->c, offset, rfv->hlen); + if (rfv_buf) { int copy = min(rfv->hlen - offset, len); if (skb->ip_summed == CHECKSUM_PARTIAL) - memcpy(to, rfv->c + offset, copy); + memcpy(to, rfv_buf, copy); else skb->csum = csum_block_add( skb->csum, - csum_partial_copy_nocheck(rfv->c + offset, - to, copy, 0), + csum_partial_copy_nocheck(rfv_buf, to, copy, 0), odd); odd = 0;