From patchwork Wed Jun 6 10:35:48 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Prasad Pandit X-Patchwork-Id: 10450047 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A3E9760146 for ; Wed, 6 Jun 2018 10:37:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 919F028649 for ; Wed, 6 Jun 2018 10:37:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 836A3299BF; Wed, 6 Jun 2018 10:37:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 005DB28649 for ; Wed, 6 Jun 2018 10:37:52 +0000 (UTC) Received: from localhost ([::1]:51335 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fQVpA-0007Gg-7y for patchwork-qemu-devel@patchwork.kernel.org; Wed, 06 Jun 2018 06:37:52 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48392) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fQVnL-000657-3a for qemu-devel@nongnu.org; Wed, 06 Jun 2018 06:36:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fQVnJ-0001e5-V0 for qemu-devel@nongnu.org; Wed, 06 Jun 2018 06:35:59 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:46592 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fQVnJ-0001dv-Qd for qemu-devel@nongnu.org; Wed, 06 Jun 2018 06:35:57 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 54523C12BA; Wed, 6 Jun 2018 10:35:57 +0000 (UTC) Received: from localhost.localdomain (ovpn-204-133.brq.redhat.com [10.40.204.133]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AF6702017D05; Wed, 6 Jun 2018 10:35:55 +0000 (UTC) From: P J P To: Qemu Developers Date: Wed, 6 Jun 2018 16:05:48 +0530 Message-Id: <20180606103549.12031-2-ppandit@redhat.com> In-Reply-To: <20180606103549.12031-1-ppandit@redhat.com> References: <20180606103549.12031-1-ppandit@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Wed, 06 Jun 2018 10:35:57 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Wed, 06 Jun 2018 10:35:57 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'ppandit@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH v1 1/2] slirp: correct size computation while concatenating mbuf X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Samuel Thibault , Prasad J Pandit , Jan Kiszka Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Prasad J Pandit While reassembling incoming fragmented datagrams, 'm_cat' routine extends the 'mbuf' buffer, if it has insufficient room. It computes a wrong buffer size, which leads to overwriting adjacent heap buffer area. Correct this size computation in m_cat. Reported-by: ZDI Disclosures Signed-off-by: Prasad J Pandit --- slirp/mbuf.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) Update v1: fixed indentation https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg01121.html diff --git a/slirp/mbuf.c b/slirp/mbuf.c index 5ff24559fd..6650981fc7 100644 --- a/slirp/mbuf.c +++ b/slirp/mbuf.c @@ -137,8 +137,9 @@ m_cat(struct mbuf *m, struct mbuf *n) /* * If there's no room, realloc */ - if (M_FREEROOM(m) < n->m_len) - m_inc(m,m->m_size+MINCSIZE); + if (M_FREEROOM(m) < n->m_len) { + m_inc(m, m->m_len + n->m_len); + } memcpy(m->m_data+m->m_len, n->m_data, n->m_len); m->m_len += n->m_len; @@ -158,12 +159,12 @@ m_inc(struct mbuf *m, int size) if (m->m_flags & M_EXT) { datasize = m->m_data - m->m_ext; - m->m_ext = g_realloc(m->m_ext, size); + m->m_ext = g_realloc(m->m_ext, size + datasize); m->m_data = m->m_ext + datasize; } else { char *dat; datasize = m->m_data - m->m_dat; - dat = g_malloc(size); + dat = g_malloc(size + datasize); memcpy(dat, m->m_dat, m->m_size); m->m_ext = dat; @@ -171,7 +172,7 @@ m_inc(struct mbuf *m, int size) m->m_flags |= M_EXT; } - m->m_size = size; + m->m_size = size + datasize; }