qemu-e2k/include/authz/pamacct.h

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authz: add QAuthZPAM object type for authorizing using PAM 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 <<EOF account requisite pam_listfile.so item=user sense=allow file=/etc/qemu/vnc.allow EOF The /etc/qemu/vnc.allow file simply contains one username per line. Any username not in the file is denied. The usernames in this example are the x509 distinguished name from the client's x509 cert. $ cat > /etc/qemu/vnc.allow <<EOF CN=laptop.berrange.com,O=Berrange Home,L=London,ST=London,C=GB EOF More interesting would be to configure PAM to use an LDAP backend, so that the QEMU authorization check data can be centralized instead of requiring each compute host to have file maintained. The main limitation with this PAM module is that the rules apply to all QEMU instances on the host. Setting up different rules per VM, would require creating a separate PAM service name & config file for every guest. An alternative approach for the future might be to not pass in the plain username to PAM, but instead combine the VM name or UUID with the username. This requires further consideration though. Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-07-27 15:13:56 +02:00
/*
* 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 <http://www.gnu.org/licenses/>.
*
*/
#ifndef QAUTHZ_PAMACCT_H
#define QAUTHZ_PAMACCT_H
authz: add QAuthZPAM object type for authorizing using PAM 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 <<EOF account requisite pam_listfile.so item=user sense=allow file=/etc/qemu/vnc.allow EOF The /etc/qemu/vnc.allow file simply contains one username per line. Any username not in the file is denied. The usernames in this example are the x509 distinguished name from the client's x509 cert. $ cat > /etc/qemu/vnc.allow <<EOF CN=laptop.berrange.com,O=Berrange Home,L=London,ST=London,C=GB EOF More interesting would be to configure PAM to use an LDAP backend, so that the QEMU authorization check data can be centralized instead of requiring each compute host to have file maintained. The main limitation with this PAM module is that the rules apply to all QEMU instances on the host. Setting up different rules per VM, would require creating a separate PAM service name & config file for every guest. An alternative approach for the future might be to not pass in the plain username to PAM, but instead combine the VM name or UUID with the username. This requires further consideration though. Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-07-27 15:13:56 +02:00
#include "authz/base.h"
#include "qom/object.h"
authz: add QAuthZPAM object type for authorizing using PAM 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 <<EOF account requisite pam_listfile.so item=user sense=allow file=/etc/qemu/vnc.allow EOF The /etc/qemu/vnc.allow file simply contains one username per line. Any username not in the file is denied. The usernames in this example are the x509 distinguished name from the client's x509 cert. $ cat > /etc/qemu/vnc.allow <<EOF CN=laptop.berrange.com,O=Berrange Home,L=London,ST=London,C=GB EOF More interesting would be to configure PAM to use an LDAP backend, so that the QEMU authorization check data can be centralized instead of requiring each compute host to have file maintained. The main limitation with this PAM module is that the rules apply to all QEMU instances on the host. Setting up different rules per VM, would require creating a separate PAM service name & config file for every guest. An alternative approach for the future might be to not pass in the plain username to PAM, but instead combine the VM name or UUID with the username. This requires further consideration though. Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-07-27 15:13:56 +02:00
#define TYPE_QAUTHZ_PAM "authz-pam"
OBJECT_DECLARE_SIMPLE_TYPE(QAuthZPAM,
QAUTHZ_PAM)
authz: add QAuthZPAM object type for authorizing using PAM 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 <<EOF account requisite pam_listfile.so item=user sense=allow file=/etc/qemu/vnc.allow EOF The /etc/qemu/vnc.allow file simply contains one username per line. Any username not in the file is denied. The usernames in this example are the x509 distinguished name from the client's x509 cert. $ cat > /etc/qemu/vnc.allow <<EOF CN=laptop.berrange.com,O=Berrange Home,L=London,ST=London,C=GB EOF More interesting would be to configure PAM to use an LDAP backend, so that the QEMU authorization check data can be centralized instead of requiring each compute host to have file maintained. The main limitation with this PAM module is that the rules apply to all QEMU instances on the host. Setting up different rules per VM, would require creating a separate PAM service name & config file for every guest. An alternative approach for the future might be to not pass in the plain username to PAM, but instead combine the VM name or UUID with the username. This requires further consideration though. Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-07-27 15:13:56 +02:00
/**
* 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;
};
QAuthZPAM *qauthz_pam_new(const char *id,
const char *service,
Error **errp);
#endif /* QAUTHZ_PAMACCT_H */