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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5FA66ECAAA1 for ; Tue, 6 Sep 2022 10:17:23 +0000 (UTC) Received: from localhost ([::1]:41584 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oVVdy-0001Mq-61 for qemu-devel@archiver.kernel.org; Tue, 06 Sep 2022 06:17:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47116) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oVUuK-0005kL-OU for qemu-devel@nongnu.org; Tue, 06 Sep 2022 05:30:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:33160) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oVUuG-0005Yd-GB for qemu-devel@nongnu.org; Tue, 06 Sep 2022 05:30:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1662456607; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bDwRtBmdRIlco6nQzhPnQOZp+rIoluS1D/vlJMcUPcA=; b=P6CK8mAMCAfwoBP1O0Nb7LBg0L294zrCVofmaU9PZG5trWTIghwwbbH2C2hzV1y1dJmwek UaZgnYYXDu85fi398U6RaSEHlWAypffhtsouscX5D5dfEMaqIGM9te7t4+09QB5pO2sdQs AErLnSKTfwQpLTI1BDlWZXFsWeQbRAY= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-57-g_uErOuIPw2F0_vdKoV8QA-1; Tue, 06 Sep 2022 05:30:06 -0400 X-MC-Unique: g_uErOuIPw2F0_vdKoV8QA-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 51C20801755 for ; Tue, 6 Sep 2022 09:30:06 +0000 (UTC) Received: from localhost (unknown [10.39.193.165]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0101D492C3B; Tue, 6 Sep 2022 09:30:05 +0000 (UTC) Date: Tue, 6 Sep 2022 10:30:05 +0100 From: "Richard W.M. Jones" To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Cc: qemu-devel@nongnu.org Subject: Re: [PATCH 01/11] crypto: sanity check that LUKS header strings are NUL-terminated Message-ID: <20220906093005.GN7484@redhat.com> References: <20220906084147.1423045-1-berrange@redhat.com> <20220906084147.1423045-2-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220906084147.1423045-2-berrange@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 Received-SPF: pass client-ip=170.10.129.124; envelope-from=rjones@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Sep 06, 2022 at 09:41:37AM +0100, Daniel P. Berrangé wrote: > The LUKS spec requires that header strings are NUL-terminated, and our > code relies on that. Protect against maliciously crafted headers by > adding validation. > > Signed-off-by: Daniel P. Berrangé > --- > crypto/block-luks.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/crypto/block-luks.c b/crypto/block-luks.c > index f62be6836b..27d1b34c1d 100644 > --- a/crypto/block-luks.c > +++ b/crypto/block-luks.c > @@ -554,6 +554,24 @@ qcrypto_block_luks_check_header(const QCryptoBlockLUKS *luks, Error **errp) > return -1; > } > > + if (!memchr(luks->header.cipher_name, '\0', > + sizeof(luks->header.cipher_name))) { > + error_setg(errp, "LUKS header cipher name is not NUL terminated"); > + return -1; > + } > + > + if (!memchr(luks->header.cipher_mode, '\0', > + sizeof(luks->header.cipher_mode))) { > + error_setg(errp, "LUKS header cipher mode is not NUL terminated"); > + return -1; > + } > + > + if (!memchr(luks->header.hash_spec, '\0', > + sizeof(luks->header.hash_spec))) { > + error_setg(errp, "LUKS header hash spec is not NUL terminated"); > + return -1; > + } > + > /* Check all keyslots for corruption */ > for (i = 0 ; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS ; i++) { I think this was the error I originally wrote to you about, and I think it's the most important fix because non-terminated strings seem (possibly) exploitable. FWIW nbdkit does this which is slightly different: char cipher_name[33], cipher_mode[33], hash_spec[33]; /* Copy the header fields locally and ensure they are \0 terminated. */ memcpy (cipher_name, h->phdr.cipher_name, 32); cipher_name[32] = 0; memcpy (cipher_mode, h->phdr.cipher_mode, 32); cipher_mode[32] = 0; memcpy (hash_spec, h->phdr.hash_spec, 32); hash_spec[32] = 0; Anyway the change above looks good so: Reviewed-by: Richard W.M. Jones Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW