From 8953caf3cd38534f8f63f4250f4ba4b4da4ff543 Mon Sep 17 00:00:00 2001 From: "Daniel P. Berrange" Date: Wed, 27 Jul 2016 14:13:56 +0100 Subject: authz: add QAuthZPAM object type for authorizing using PAM MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 < Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Daniel P. Berrange --- authz/Makefile.objs | 3 ++ authz/pamacct.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++++++++ authz/trace-events | 3 ++ 3 files changed, 154 insertions(+) create mode 100644 authz/pamacct.c (limited to 'authz') 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/pamacct.c b/authz/pamacct.c new file mode 100644 index 0000000000..5038358cdc --- /dev/null +++ b/authz/pamacct.c @@ -0,0 +1,148 @@ +/* + * 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); + pam_end(pamh, ret); + if (ret != PAM_SUCCESS) { + error_setg(errp, "Unable to authorize user '%s': %s", + identity, pam_strerror(pamh, ret)); + return false; + } + + return true; +} + + +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/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" -- cgit v1.2.3