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 DF25BC433EF for ; Tue, 4 Jan 2022 18:52:09 +0000 (UTC) Received: from localhost ([::1]:44106 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n4oum-0001kZ-Sl for qemu-devel@archiver.kernel.org; Tue, 04 Jan 2022 13:52:08 -0500 Received: from eggs.gnu.org ([209.51.188.92]:52516) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n4onN-0005mH-9u for qemu-devel@nongnu.org; Tue, 04 Jan 2022 13:44:29 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:26281) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n4onL-0007xe-B1 for qemu-devel@nongnu.org; Tue, 04 Jan 2022 13:44:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1641321866; h=from:from:reply-to: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=Q6CGT+trdRuujURpK1psMiFidPx068lat9wSkAi6MQI=; b=YX42ygDzG+4KUzPf+ZpHidnLTq+UuGKiKhABRkwKcQDlF/OYbLQQhGrOAvcxrDgcfHYJKt tEyx6d2PoGr5n1s5CSsXepjRjOiX/6kfAGHGwz6pRmD9Uh1yqTb+9DVxvWct5m9D4o87UL 7KWokP6rYRJ4Kl5IG1hFNWzDF4hJ+LQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-651-MXFPWKsJNtmj693l_BpMcg-1; Tue, 04 Jan 2022 13:44:23 -0500 X-MC-Unique: MXFPWKsJNtmj693l_BpMcg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 539C8190A7A6; Tue, 4 Jan 2022 18:44:22 +0000 (UTC) Received: from redhat.com (unknown [10.22.32.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 188B58032C; Tue, 4 Jan 2022 18:44:20 +0000 (UTC) Date: Tue, 4 Jan 2022 18:44:18 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Henry Kleynhans Subject: Re: [PATCH 2/2] [crypto] Only verify CA certs in chain of trust Message-ID: References: <20211222150600.37677-1-henry.kleynhans@gmail.com> <20211222150600.37677-2-henry.kleynhans@gmail.com> MIME-Version: 1.0 In-Reply-To: <20211222150600.37677-2-henry.kleynhans@gmail.com> User-Agent: Mutt/2.1.3 (2021-09-10) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -12 X-Spam_score: -1.3 X-Spam_bar: - X-Spam_report: (-1.3 / 5.0 requ) DKIMWL_WL_HIGH=-0.37, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Henry Kleynhans , qemu-devel@nongnu.org, henry.kleynhans@fb.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Dec 22, 2021 at 03:06:00PM +0000, Henry Kleynhans wrote: > From: Henry Kleynhans > > The CA file provided to qemu may contain CA certificates which do not > form part of the chain of trust for the specific certificate we are > sanity checking. > > This patch changes the sanity checking from validating every CA > certificate to only checking the CA certificates which are part of the > chain of trust (issuer chain). Other certificates are ignored. > > Signed-off-by: Henry Kleynhans > --- > crypto/tlscredsx509.c | 50 +++++++++++++++++++++++---- > tests/unit/test-crypto-tlscredsx509.c | 25 +++++++++++++- > 2 files changed, 68 insertions(+), 7 deletions(-) Reviewed-by: Daniel P. Berrangé > > diff --git a/crypto/tlscredsx509.c b/crypto/tlscredsx509.c > index d061c68253..841f80aac6 100644 > --- a/crypto/tlscredsx509.c > +++ b/crypto/tlscredsx509.c > @@ -315,6 +315,44 @@ qcrypto_tls_creds_check_cert(QCryptoTLSCredsX509 *creds, > return 0; > } > > +static int > +qcrypto_tls_creds_check_authority_chain(QCryptoTLSCredsX509 *creds, > + gnutls_x509_crt_t cert, > + gnutls_x509_crt_t *cacerts, > + unsigned int ncacerts, > + const char *cacertFile, > + bool isServer, > + bool isCA, > + Error **errp) > +{ > + gnutls_x509_crt_t *cert_to_check = &cert; > + int checking_issuer = 1; > + int retval = 0; > + > + while (checking_issuer) { > + checking_issuer = 0; > + > + if (gnutls_x509_crt_check_issuer(*cert_to_check, *cert_to_check)) { > + /* The cert is self-signed indicating we have reached the root of trust. */ > + return qcrypto_tls_creds_check_cert(creds, *cert_to_check, cacertFile, > + isServer, isCA, errp); > + } > + for (int i = 0; i < ncacerts; i++) { > + if (gnutls_x509_crt_check_issuer(*cert_to_check, cacerts[i])) { > + retval = qcrypto_tls_creds_check_cert(creds, cacerts[i], cacertFile, > + isServer, isCA, errp); > + if (retval < 0) { > + return retval; > + } > + cert_to_check = &cacerts[i]; > + checking_issuer = 1; > + break; > + } > + } > + } > + > + return -1; I have a feeling this should be 'return 0'. eg consider the case where the cacert.pem does not contain the issuer of clientcert.pem. we will only do one iteration of the while(checking_issuer) loop, not hitting any of the 'return' statements. This is ok, so should report success I think. > +} > > static int > qcrypto_tls_creds_check_cert_pair(gnutls_x509_crt_t cert, > @@ -500,12 +538,12 @@ qcrypto_tls_creds_x509_sanity_check(QCryptoTLSCredsX509 *creds, > goto cleanup; > } > > - for (i = 0; i < ncacerts; i++) { > - if (qcrypto_tls_creds_check_cert(creds, > - cacerts[i], cacertFile, > - isServer, true, errp) < 0) { > - goto cleanup; > - } > + if (cert && > + qcrypto_tls_creds_check_authority_chain(creds, cert, > + cacerts, ncacerts, > + cacertFile, isServer, > + true, errp) < 0) { > + goto cleanup; > } > > if (cert && ncacerts && > diff --git a/tests/unit/test-crypto-tlscredsx509.c b/tests/unit/test-crypto-tlscredsx509.c > index aab4149b56..e4d657ba61 100644 > --- a/tests/unit/test-crypto-tlscredsx509.c > +++ b/tests/unit/test-crypto-tlscredsx509.c > @@ -589,6 +589,12 @@ int main(int argc, char **argv) > true, true, GNUTLS_KEY_KEY_CERT_SIGN, > false, false, NULL, NULL, > 0, 0); > + TLS_CERT_REQ(cacertlevel1creq_invalid, cacertrootreq, > + "UK", "qemu level 1c invalid", NULL, NULL, NULL, NULL, > + true, true, true, > + true, true, GNUTLS_KEY_KEY_CERT_SIGN, > + false, false, NULL, NULL, > + 360, 400); > TLS_CERT_REQ(cacertlevel2areq, cacertlevel1areq, > "UK", "qemu level 2a", NULL, NULL, NULL, NULL, > true, true, true, > @@ -617,16 +623,32 @@ int main(int argc, char **argv) > cacertlevel2areq.crt, > }; > > + > test_tls_write_cert_chain(WORKDIR "cacertchain-ctx.pem", > certchain, > G_N_ELEMENTS(certchain)); > > + gnutls_x509_crt_t certchain_with_invalid[] = { > + cacertrootreq.crt, > + cacertlevel1areq.crt, > + cacertlevel1breq.crt, > + cacertlevel1creq_invalid.crt, > + cacertlevel2areq.crt, > + }; > + > + test_tls_write_cert_chain(WORKDIR "cacertchain-with-invalid-ctx.pem", > + certchain_with_invalid, > + G_N_ELEMENTS(certchain_with_invalid)); > + > TLS_TEST_REG(chain1, true, > WORKDIR "cacertchain-ctx.pem", > servercertlevel3areq.filename, false); > TLS_TEST_REG(chain2, false, > WORKDIR "cacertchain-ctx.pem", > clientcertlevel2breq.filename, false); > + TLS_TEST_REG(certchainwithexpiredcert, false, > + WORKDIR "cacertchain-with-invalid-ctx.pem", > + clientcertlevel2breq.filename, false); > > /* Some missing certs - first two are fatal, the last > * is ok > @@ -640,7 +662,6 @@ int main(int argc, char **argv) > TLS_TEST_REG(missingclient, false, > cacert1req.filename, > "clientcertdoesnotexist.pem", false); > - > ret = g_test_run(); > > test_tls_discard_cert(&cacertreq); > @@ -694,10 +715,12 @@ int main(int argc, char **argv) > test_tls_discard_cert(&cacertrootreq); > test_tls_discard_cert(&cacertlevel1areq); > test_tls_discard_cert(&cacertlevel1breq); > + test_tls_discard_cert(&cacertlevel1creq_invalid); > test_tls_discard_cert(&cacertlevel2areq); > test_tls_discard_cert(&servercertlevel3areq); > test_tls_discard_cert(&clientcertlevel2breq); > unlink(WORKDIR "cacertchain-ctx.pem"); > + unlink(WORKDIR "cacertchain-with-invalid-ctx.pem"); > > test_tls_cleanup(KEYFILE); > rmdir(WORKDIR); > -- > 2.34.1 > Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|