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=-16.8 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 F0E5BC0018C for ; Sat, 19 Dec 2020 12:59:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D143023AC2 for ; Sat, 19 Dec 2020 12:59:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728088AbgLSM7U (ORCPT ); Sat, 19 Dec 2020 07:59:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:45496 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727849AbgLSM6u (ORCPT ); Sat, 19 Dec 2020 07:58:50 -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, syzbot+9d39fa49d4df294aab93@syzkaller.appspotmail.com, Michal Kubecek , Jakub Kicinski Subject: [PATCH 5.9 22/49] ethtool: fix stack overflow in ethnl_parse_bitset() Date: Sat, 19 Dec 2020 13:58:26 +0100 Message-Id: <20201219125345.771146133@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201219125344.671832095@linuxfoundation.org> References: <20201219125344.671832095@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: Michal Kubecek [ Upstream commit a770bf515613c6e12ae904c3593e26016de99448 ] Syzbot reported a stack overflow in bitmap_from_arr32() called from ethnl_parse_bitset() when bitset from netlink message is longer than target bitmap length. While ethnl_compact_sanity_checks() makes sure that trailing part is all zeros (i.e. the request does not try to touch bits kernel does not recognize), we also need to cap change_bits to nbits so that we don't try to write past the prepared bitmaps. Fixes: 88db6d1e4f62 ("ethtool: add ethnl_parse_bitset() helper") Reported-by: syzbot+9d39fa49d4df294aab93@syzkaller.appspotmail.com Signed-off-by: Michal Kubecek Link: https://lore.kernel.org/r/3487ee3a98e14cd526f55b6caaa959d2dcbcad9f.1607465316.git.mkubecek@suse.cz Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/ethtool/bitset.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/ethtool/bitset.c +++ b/net/ethtool/bitset.c @@ -630,6 +630,8 @@ int ethnl_parse_bitset(unsigned long *va return ret; change_bits = nla_get_u32(tb[ETHTOOL_A_BITSET_SIZE]); + if (change_bits > nbits) + change_bits = nbits; bitmap_from_arr32(val, nla_data(tb[ETHTOOL_A_BITSET_VALUE]), change_bits); if (change_bits < nbits)