From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39480) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fRKth-0007FS-IT for qemu-devel@nongnu.org; Fri, 08 Jun 2018 13:09:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fRKtf-0008TX-Fq for qemu-devel@nongnu.org; Fri, 08 Jun 2018 13:09:57 -0400 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Fri, 8 Jun 2018 18:09:32 +0100 Message-Id: <20180608170933.9137-8-berrange@redhat.com> In-Reply-To: <20180608170933.9137-1-berrange@redhat.com> References: <20180608170933.9137-1-berrange@redhat.com> Subject: [Qemu-devel] [PATCH 7/8] authz: add QAuthZPAM object type for authorizing using PAM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Markus Armbruster , =?UTF-8?q?Andreas=20F=C3=A4rber?= , Laurent Vivier , Gerd Hoffmann , "Dr. David Alan Gilbert" , qemu-trivial@nongnu.org, =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eric Blake , Michael Tokarev 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 < --- authz/Makefile.objs | 3 + authz/pam.c | 149 ++++++++++++++++++++++++++++++++++++++++++++ authz/trace-events | 3 + configure | 36 +++++++++++ include/authz/pam.h | 84 +++++++++++++++++++++++++ 5 files changed, 275 insertions(+) create mode 100644 authz/pam.c create mode 100644 include/authz/pam.h diff --git a/authz/Makefile.objs b/authz/Makefile.objs index 8351bf181d..1276421c22 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) += pam.o + +pam.o-libs = -lpam diff --git a/authz/pam.c b/authz/pam.c new file mode 100644 index 0000000000..d3dd49b343 --- /dev/null +++ b/authz/pam.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/pam.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/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/configure b/configure index 14b11130a7..85d2ac4b78 100755 --- a/configure +++ b/configure @@ -445,6 +445,7 @@ nettle_kdf="no" gcrypt="" gcrypt_hmac="no" gcrypt_kdf="no" +auth_pam="" vte="" virglrenderer="" tpm="yes" @@ -1310,6 +1311,10 @@ 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" @@ -1575,6 +1580,7 @@ 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 @@ -2814,6 +2820,32 @@ else fi +########################################## +# PAM probe + +if test "x$auth_pam" != "no"; then + cat > $TMPC < +#include +int main(void) { + const char *service_name = "qemu"; + const char *user = "frank"; + const struct pam_conv *pam_conv = NULL; + pam_handle_t *pamh = NULL; + pam_start(service_name, user, pam_conv, &pamh); +} +EOF + if compile_prog "" "-lpam" ; then + auth_pam=yes + else + if test "$auth_pam" = "yes"; then + feature_not_found "PAM" "Install pam-devel" + else + auth_pam=no + fi + fi +fi + ########################################## # getifaddrs (for tests/test-io-channel-socket ) @@ -5826,6 +5858,7 @@ 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 "curl support $curl" @@ -6286,6 +6319,9 @@ fi if test "$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/pam.h b/include/authz/pam.h new file mode 100644 index 0000000000..461313c15b --- /dev/null +++ b/include/authz/pam.h @@ -0,0 +1,84 @@ +/* + * 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": "auth0", + * "parameters": { + * "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__ */ + -- 2.17.0