From patchwork Fri Oct 19 13:38:34 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= X-Patchwork-Id: 10649539 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 14CC113A4 for ; Fri, 19 Oct 2018 13:48:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 014322074F for ; Fri, 19 Oct 2018 13:48:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E931822B26; Fri, 19 Oct 2018 13:48:31 +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=-5.9 required=2.0 tests=BAYES_00,LONGWORDS, 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 E5DBC2074F for ; Fri, 19 Oct 2018 13:48:30 +0000 (UTC) Received: from localhost ([::1]:50658 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gDV8g-0004FD-8F for patchwork-qemu-devel@patchwork.kernel.org; Fri, 19 Oct 2018 09:48:30 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38160) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gDUzf-0004my-Q7 for qemu-devel@nongnu.org; Fri, 19 Oct 2018 09:39:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gDUzb-0000VN-Hg for qemu-devel@nongnu.org; Fri, 19 Oct 2018 09:39:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38794) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gDUza-0000SX-VW for qemu-devel@nongnu.org; Fri, 19 Oct 2018 09:39:07 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E002030034A1 for ; Fri, 19 Oct 2018 13:39:05 +0000 (UTC) Received: from localhost.localdomain.com (unknown [10.42.22.189]) by smtp.corp.redhat.com (Postfix) with ESMTP id 103566530B; Fri, 19 Oct 2018 13:39:03 +0000 (UTC) From: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= To: qemu-devel@nongnu.org Date: Fri, 19 Oct 2018 14:38:34 +0100 Message-Id: <20181019133835.16494-11-berrange@redhat.com> In-Reply-To: <20181019133835.16494-1-berrange@redhat.com> References: <20181019133835.16494-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Fri, 19 Oct 2018 13:39:05 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v6 10/11] authz: add QAuthZPAM object type for authorizing using PAM 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: Markus Armbruster , "Dr. David Alan Gilbert" , Gerd Hoffmann , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: "Daniel P. Berrange" Add an authorization backend that talks to PAM to check whether the user identity is allowed. This only uses the PAM account validation facility, which is essentially just a check to see if the provided username is permitted access. It doesn't use the authentication or session parts of PAM, since that's dealt with by the relevant part of QEMU (eg VNC server). Consider starting QEMU with a VNC server and telling it to use TLS with x509 client certificates and configuring it to use an PAM to validate the x509 distinguished name. In this example we're telling it to use PAM for the QAuthZ impl with a service name of "qemu-vnc" $ qemu-system-x86_64 \ -object tls-creds-x509,id=tls0,dir=/home/berrange/security/qemutls,\ endpoint=server,verify-peer=yes \ -object authz-pam,id=authz0,service=qemu-vnc \ -vnc :1,tls-creds=tls0,tls-authz=authz0 This requires an /etc/pam/qemu-vnc file to be created with the auth rules. A very simple file based whitelist can be setup using $ cat > /etc/pam/qemu-vnc < /etc/qemu/vnc.allow < Tested-by: Philippe Mathieu-Daudé Signed-off-by: Daniel P. Berrange Reviewed-by: Marc-André Lureau --- configure | 37 ++++++++++ include/authz/pamacct.h | 100 +++++++++++++++++++++++++++ authz/pamacct.c | 149 ++++++++++++++++++++++++++++++++++++++++ authz/Makefile.objs | 3 + authz/trace-events | 3 + qemu-options.hx | 35 ++++++++++ 6 files changed, 327 insertions(+) create mode 100644 include/authz/pamacct.h create mode 100644 authz/pamacct.c diff --git a/configure b/configure index 9138af37f8..db35d52e12 100755 --- a/configure +++ b/configure @@ -463,6 +463,7 @@ nettle_kdf="no" gcrypt="" gcrypt_hmac="no" gcrypt_kdf="no" +auth_pam="" vte="" virglrenderer="" tpm="yes" @@ -1361,6 +1362,10 @@ for opt do ;; --enable-gcrypt) gcrypt="yes" ;; + --disable-auth-pam) auth_pam="no" + ;; + --enable-auth-pam) auth_pam="yes" + ;; --enable-rdma) rdma="yes" ;; --disable-rdma) rdma="no" @@ -1653,6 +1658,7 @@ disabled with --disable-FEATURE, default is enabled if available: gnutls GNUTLS cryptography support nettle nettle cryptography support gcrypt libgcrypt cryptography support + auth-pam PAM access control sdl SDL UI --with-sdlabi select preferred SDL ABI 1.2 or 2.0 gtk gtk UI @@ -2876,6 +2882,33 @@ else fi +########################################## +# PAM probe + +if test "x$auth_pam" != "no"; then + cat > $TMPC < +#include +int main(void) { + const char *service_name = "qemu"; + const char *user = "frank"; + const struct pam_conv *pam_conv = NULL; + pam_handle_t *pamh = NULL; + pam_start(service_name, user, pam_conv, &pamh); + return 0; +} +EOF + if compile_prog "" "-lpam" ; then + auth_pam=yes + else + if test "$auth_pam" = "yes"; then + feature_not_found "PAM" "Install PAM development package" + else + auth_pam=no + fi + fi +fi + ########################################## # getifaddrs (for tests/test-io-channel-socket ) @@ -5967,6 +6000,7 @@ echo "libgcrypt kdf $gcrypt_kdf" echo "nettle $nettle $(echo_version $nettle $nettle_version)" echo "nettle kdf $nettle_kdf" echo "libtasn1 $tasn1" +echo "PAM $auth_pam" echo "curses support $curses" echo "virgl support $virglrenderer $(echo_version $virglrenderer $virgl_version)" echo "curl support $curl" @@ -6423,6 +6457,9 @@ fi if test "$tasn1" = "yes" ; then echo "CONFIG_TASN1=y" >> $config_host_mak fi +if test "$auth_pam" = "yes" ; then + echo "CONFIG_AUTH_PAM=y" >> $config_host_mak +fi if test "$have_ifaddrs_h" = "yes" ; then echo "HAVE_IFADDRS_H=y" >> $config_host_mak fi diff --git a/include/authz/pamacct.h b/include/authz/pamacct.h new file mode 100644 index 0000000000..d2c0149153 --- /dev/null +++ b/include/authz/pamacct.h @@ -0,0 +1,100 @@ +/* + * QEMU PAM authorization driver + * + * Copyright (c) 2018 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see . + * + */ + +#ifndef QAUTHZ_PAM_H__ +#define QAUTHZ_PAM_H__ + +#include "authz/base.h" + + +#define TYPE_QAUTHZ_PAM "authz-pam" + +#define QAUTHZ_PAM_CLASS(klass) \ + OBJECT_CLASS_CHECK(QAuthZPamClass, (klass), \ + TYPE_QAUTHZ_PAM) +#define QAUTHZ_PAM_GET_CLASS(obj) \ + OBJECT_GET_CLASS(QAuthZPamClass, (obj), \ + TYPE_QAUTHZ_PAM) +#define QAUTHZ_PAM(obj) \ + INTERFACE_CHECK(QAuthZPam, (obj), \ + TYPE_QAUTHZ_PAM) + +typedef struct QAuthZPam QAuthZPam; +typedef struct QAuthZPamClass QAuthZPamClass; + + +/** + * QAuthZPam: + * + * This authorization driver provides a PAM mechanism + * for granting access by matching user names against a + * list of globs. Each match rule has an associated policy + * and a catch all policy applies if no rule matches + * + * To create an instance of this class via QMP: + * + * { + * "execute": "object-add", + * "arguments": { + * "qom-type": "authz-pam", + * "id": "authz0", + * "parameters": { + * "service": "qemu-vnc-tls" + * } + * } + * } + * + * The driver only uses the PAM "account" verification + * subsystem. The above config would require a config + * file /etc/pam.d/qemu-vnc-tls. For a simple file + * lookup it would contain + * + * account requisite pam_listfile.so item=user sense=allow \ + * file=/etc/qemu/vnc.allow + * + * The external file would then contain a list of usernames. + * If x509 cert was being used as the username, a suitable + * entry would match the distinguish name: + * + * CN=laptop.berrange.com,O=Berrange Home,L=London,ST=London,C=GB + * + * On the command line it can be created using + * + * -object authz-pam,id=authz0,service=qemu-vnc-tls + * + */ +struct QAuthZPam { + QAuthZ parent_obj; + + char *service; +}; + + +struct QAuthZPamClass { + QAuthZClass parent_class; +}; + + +QAuthZPam *qauthz_pam_new(const char *id, + const char *service, + Error **errp); + + +#endif /* QAUTHZ_PAM_H__ */ diff --git a/authz/pamacct.c b/authz/pamacct.c new file mode 100644 index 0000000000..a070dda217 --- /dev/null +++ b/authz/pamacct.c @@ -0,0 +1,149 @@ +/* + * QEMU PAM authorization driver + * + * Copyright (c) 2018 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see . + * + */ + +#include "qemu/osdep.h" +#include "authz/pamacct.h" +#include "authz/trace.h" +#include "qom/object_interfaces.h" + +#include + + +static bool qauthz_pam_is_allowed(QAuthZ *authz, + const char *identity, + Error **errp) +{ + QAuthZPam *pauthz = QAUTHZ_PAM(authz); + const struct pam_conv pam_conversation = { 0 }; + pam_handle_t *pamh = NULL; + int ret; + + trace_qauthz_pam_check(authz, identity, pauthz->service); + ret = pam_start(pauthz->service, + identity, + &pam_conversation, + &pamh); + if (ret != PAM_SUCCESS) { + error_setg(errp, "Unable to start PAM transaction: %s", + pam_strerror(NULL, ret)); + return false; + } + + ret = pam_acct_mgmt(pamh, PAM_SILENT); + if (ret != PAM_SUCCESS) { + error_setg(errp, "Unable to authorize user '%s': %s", + identity, pam_strerror(pamh, ret)); + goto cleanup; + } + + cleanup: + pam_end(pamh, ret); + return ret == PAM_SUCCESS; +} + + +static void +qauthz_pam_prop_set_service(Object *obj, + const char *service, + Error **errp G_GNUC_UNUSED) +{ + QAuthZPam *pauthz = QAUTHZ_PAM(obj); + + g_free(pauthz->service); + pauthz->service = g_strdup(service); +} + + +static char * +qauthz_pam_prop_get_service(Object *obj, + Error **errp G_GNUC_UNUSED) +{ + QAuthZPam *pauthz = QAUTHZ_PAM(obj); + + return g_strdup(pauthz->service); +} + + +static void +qauthz_pam_complete(UserCreatable *uc, Error **errp) +{ +} + + +static void +qauthz_pam_finalize(Object *obj) +{ + QAuthZPam *pauthz = QAUTHZ_PAM(obj); + + g_free(pauthz->service); +} + + +static void +qauthz_pam_class_init(ObjectClass *oc, void *data) +{ + UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc); + QAuthZClass *authz = QAUTHZ_CLASS(oc); + + ucc->complete = qauthz_pam_complete; + authz->is_allowed = qauthz_pam_is_allowed; + + object_class_property_add_str(oc, "service", + qauthz_pam_prop_get_service, + qauthz_pam_prop_set_service, + NULL); +} + + +QAuthZPam *qauthz_pam_new(const char *id, + const char *service, + Error **errp) +{ + return QAUTHZ_PAM( + object_new_with_props(TYPE_QAUTHZ_PAM, + object_get_objects_root(), + id, errp, + "service", service, + NULL)); +} + + +static const TypeInfo qauthz_pam_info = { + .parent = TYPE_QAUTHZ, + .name = TYPE_QAUTHZ_PAM, + .instance_size = sizeof(QAuthZPam), + .instance_finalize = qauthz_pam_finalize, + .class_size = sizeof(QAuthZPamClass), + .class_init = qauthz_pam_class_init, + .interfaces = (InterfaceInfo[]) { + { TYPE_USER_CREATABLE }, + { } + } +}; + + +static void +qauthz_pam_register_types(void) +{ + type_register_static(&qauthz_pam_info); +} + + +type_init(qauthz_pam_register_types); diff --git a/authz/Makefile.objs b/authz/Makefile.objs index 8351bf181d..ed7b273596 100644 --- a/authz/Makefile.objs +++ b/authz/Makefile.objs @@ -2,3 +2,6 @@ authz-obj-y += base.o authz-obj-y += simple.o authz-obj-y += list.o authz-obj-y += listfile.o +authz-obj-$(CONFIG_AUTH_PAM) += pamacct.o + +pamacct.o-libs = -lpam diff --git a/authz/trace-events b/authz/trace-events index fb65349a90..72c411927d 100644 --- a/authz/trace-events +++ b/authz/trace-events @@ -13,3 +13,6 @@ qauthz_list_default_policy(void *authz, const char *identity, int policy) "AuthZ # auth/listfile.c qauthz_list_file_load(void *authz, const char *filename) "AuthZ file %p load filename=%s" qauthz_list_file_refresh(void *authz, const char *filename, int success) "AuthZ file %p load filename=%s success=%d" + +# auth/pam.c +qauthz_pam_check(void *authz, const char *identity, const char *service) "AuthZ PAM %p identity=%s service=%s" diff --git a/qemu-options.hx b/qemu-options.hx index a1c3e0e59c..a9654b8115 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -4447,6 +4447,41 @@ would look like: ... @end example +@item -object authz-pam,id=@var{id},service=@var{string} + +Create an authorization object that will control access to network services. + +The @option{service} parameter provides the name of a PAM service to use +for authorization. It requires that a file @code{/etc/pam.d/@var{service}} +exist to provide the configuration for the @code{account} subsystem. + +An example authorization object to validate a TLS x509 distinguished +name would look like: + +@example + # $QEMU \ + ... + -object authz-simple,id=auth0,service=qemu-vnc + ... +@end example + +There would then be a corresponding config file for PAM at +@code{/etc/pam.d/qemu-vnc} that contains: + +@example +account requisite pam_listfile.so item=user sense=allow \ + file=/etc/qemu/vnc.allow +@end example + +Finally the @code{/etc/qemu/vnc.allow} file would contain +the list of x509 distingished names that are permitted +access + +@example +CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB +@end example + + @end table ETEXI