Discussion:
[libvirt] [PATCH v3 0/6] Add authorization support to all network services
Daniel P. Berrangé
2018-10-09 13:23:24 UTC
Permalink
v1: https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg04482.html
v2: https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg05727.html

This series builds on the core authorization framework:

v5: https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg01613.html

enabling its use with the VNC, chardev, NBD and migration network servers.

In combination with TLS x509 client certificates, this allows these
services to whitelist specific clients, which avoids the need to setup
restricted child certificate authorities.

In VNC it also allows whitelisting based on SASL user names.

Changed in v3:

- Rebased to latest git master

Changed in v2:

- Document that authz objects are resolved at time of use, not
time of network service activation
- Improve docs for tls-authz parameters on services
- Fix 2.13 -> 3.0 version tags
- Remove redundant conditionals around g_strdup
- Fix arg syntax for qemu-nbd s/-/--/
- Remove QAPI (optional) annotation
- Fix some outdated usage example

Based-on: <20181009130442.26296-1-***@redhat.com>

Daniel P. Berrangé (6):
qemu-nbd: add support for authorization of TLS clients
nbd: allow authorization with nbd-server-start QMP command
migration: add support for a "tls-authz" migration parameter
chardev: add support for authorization for TLS clients
vnc: allow specifying a custom authorization object name
monitor: deprecate acl_show, acl_reset, acl_policy, acl_add,
acl_remove

blockdev-nbd.c | 11 +++++---
chardev/char-socket.c | 11 +++++++-
chardev/char.c | 3 +++
hmp.c | 11 +++++++-
include/block/nbd.h | 4 +--
migration/migration.c | 8 ++++++
migration/tls.c | 2 +-
monitor.c | 23 +++++++++++++++++
nbd/server.c | 10 ++++----
qapi/block.json | 8 +++++-
qapi/char.json | 6 +++++
qapi/migration.json | 14 ++++++++++-
qemu-deprecated.texi | 11 ++++++++
qemu-nbd.c | 13 +++++++++-
qemu-nbd.texi | 4 +++
qemu-options.hx | 44 +++++++++++++++++++++++---------
ui/vnc.c | 58 ++++++++++++++++++++++++++++++++++++-------
17 files changed, 204 insertions(+), 37 deletions(-)
--
2.17.1
Daniel P. Berrangé
2018-10-09 13:23:25 UTC
Permalink
From: "Daniel P. Berrange" <***@redhat.com>

Currently any client which can complete the TLS handshake is able to use
the NBD server. The server admin can turn on the 'verify-peer' option
for the x509 creds to require the client to provide a x509 certificate.
This means the client will have to acquire a certificate from the CA
before they are permitted to use the NBD server. This is still a fairly
low bar to cross.

This adds a '--tls-authz OBJECT-ID' option to the qemu-nbd command which
takes the ID of a previously added 'QAuthZ' object instance. This will
be used to validate the client's x509 distinguished name. Clients
failing the authorization check will not be permitted to use the NBD
server.

For example to setup authorization that only allows connection from a client
whose x509 certificate distinguished name is

CN=laptop.example.com,O=Example Org,L=London,ST=London,C=GB

use:

qemu-nbd --object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
--object authz-simple,id=auth0,identity=CN=laptop.example.com,,\
O=Example Org,,L=London,,ST=London,,C=GB \
--tls-creds tls0 \
--tls-authz authz0
....other qemu-nbd args...

Signed-off-by: Daniel P. Berrange <***@redhat.com>
---
include/block/nbd.h | 2 +-
nbd/server.c | 10 +++++-----
qemu-nbd.c | 13 ++++++++++++-
qemu-nbd.texi | 4 ++++
4 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/include/block/nbd.h b/include/block/nbd.h
index 6a5bfe5d55..d7aa6b24d0 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -312,7 +312,7 @@ void nbd_export_close_all(void);

void nbd_client_new(QIOChannelSocket *sioc,
QCryptoTLSCreds *tlscreds,
- const char *tlsaclname,
+ const char *tlsauthz,
void (*close_fn)(NBDClient *, bool));
void nbd_client_get(NBDClient *client);
void nbd_client_put(NBDClient *client);
diff --git a/nbd/server.c b/nbd/server.c
index a1eda0114f..138a35f838 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -111,7 +111,7 @@ struct NBDClient {

NBDExport *exp;
QCryptoTLSCreds *tlscreds;
- char *tlsaclname;
+ char *tlsauthz;
QIOChannelSocket *sioc; /* The underlying data channel */
QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */

@@ -687,7 +687,7 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,

tioc = qio_channel_tls_new_server(ioc,
client->tlscreds,
- client->tlsaclname,
+ client->tlsauthz,
errp);
if (!tioc) {
return NULL;
@@ -1353,7 +1353,7 @@ void nbd_client_put(NBDClient *client)
if (client->tlscreds) {
object_unref(OBJECT(client->tlscreds));
}
- g_free(client->tlsaclname);
+ g_free(client->tlsauthz);
if (client->exp) {
QTAILQ_REMOVE(&client->exp->clients, client, next);
nbd_export_put(client->exp);
@@ -2403,7 +2403,7 @@ static coroutine_fn void nbd_co_client_start(void *opaque)
*/
void nbd_client_new(QIOChannelSocket *sioc,
QCryptoTLSCreds *tlscreds,
- const char *tlsaclname,
+ const char *tlsauthz,
void (*close_fn)(NBDClient *, bool))
{
NBDClient *client;
@@ -2415,7 +2415,7 @@ void nbd_client_new(QIOChannelSocket *sioc,
if (tlscreds) {
object_ref(OBJECT(client->tlscreds));
}
- client->tlsaclname = g_strdup(tlsaclname);
+ client->tlsauthz = g_strdup(tlsauthz);
client->sioc = sioc;
object_ref(OBJECT(client->sioc));
client->ioc = QIO_CHANNEL(sioc);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index e76fe3082a..61fe0fb5b9 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -52,6 +52,7 @@
#define QEMU_NBD_OPT_TLSCREDS 261
#define QEMU_NBD_OPT_IMAGE_OPTS 262
#define QEMU_NBD_OPT_FORK 263
+#define QEMU_NBD_OPT_TLSAUTHZ 264

#define MBR_SIZE 512

@@ -65,6 +66,7 @@ static int shared = 1;
static int nb_fds;
static QIONetListener *server;
static QCryptoTLSCreds *tlscreds;
+static const char *tlsauthz;

static void usage(const char *name)
{
@@ -354,7 +356,7 @@ static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,

nb_fds++;
nbd_update_server_watch();
- nbd_client_new(cioc, tlscreds, NULL, nbd_client_closed);
+ nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
}

static void nbd_update_server_watch(void)
@@ -532,6 +534,7 @@ int main(int argc, char **argv)
{ "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
{ "trace", required_argument, NULL, 'T' },
{ "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
+ { "tls-authz", no_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
{ NULL, 0, NULL, 0 }
};
int ch;
@@ -754,6 +757,9 @@ int main(int argc, char **argv)
g_free(trace_file);
trace_file = trace_opt_parse(optarg);
break;
+ case QEMU_NBD_OPT_TLSAUTHZ:
+ tlsauthz = optarg;
+ break;
case QEMU_NBD_OPT_FORK:
fork_process = true;
break;
@@ -813,6 +819,11 @@ int main(int argc, char **argv)
error_get_pretty(local_err));
exit(EXIT_FAILURE);
}
+ } else {
+ if (tlsauthz) {
+ error_report("--tls-authz is not permitted without --tls-creds");
+ exit(EXIT_FAILURE);
+ }
}

if (disconnect) {
diff --git a/qemu-nbd.texi b/qemu-nbd.texi
index 9a84e81eed..7f9503cf05 100644
--- a/qemu-nbd.texi
+++ b/qemu-nbd.texi
@@ -91,6 +91,10 @@ of the TLS credentials object previously created with the --object
option.
@item --fork
Fork off the server process and exit the parent once the server is running.
+@item --tls-authz=ID
+Specify the ID of a qauthz object previously created with the
+--object option. This will be used to authorize connecting users
+against their x509 distinguished name.
@item -v, --verbose
Display extra debugging information
@item -h, --help
--
2.17.1
Juan Quintela
2018-10-17 12:24:42 UTC
Permalink
Post by Daniel P. Berrangé
Currently any client which can complete the TLS handshake is able to use
the NBD server. The server admin can turn on the 'verify-peer' option
for the x509 creds to require the client to provide a x509 certificate.
This means the client will have to acquire a certificate from the CA
before they are permitted to use the NBD server. This is still a fairly
low bar to cross.
This adds a '--tls-authz OBJECT-ID' option to the qemu-nbd command which
takes the ID of a previously added 'QAuthZ' object instance. This will
be used to validate the client's x509 distinguished name. Clients
failing the authorization check will not be permitted to use the NBD
server.
For example to setup authorization that only allows connection from a client
whose x509 certificate distinguished name is
CN=laptop.example.com,O=Example Org,L=London,ST=London,C=GB
qemu-nbd --object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
--object authz-simple,id=auth0,identity=CN=laptop.example.com,,\
O=Example Org,,L=London,,ST=London,,C=GB \
--tls-creds tls0 \
--tls-authz authz0
....other qemu-nbd args...
Reviewed-by: Juan Quintela <***@redhat.com>
Eric Blake
2018-11-05 22:41:09 UTC
Permalink
Post by Daniel P. Berrangé
Currently any client which can complete the TLS handshake is able to use
the NBD server. The server admin can turn on the 'verify-peer' option
for the x509 creds to require the client to provide a x509 certificate.
This means the client will have to acquire a certificate from the CA
before they are permitted to use the NBD server. This is still a fairly
low bar to cross.
This adds a '--tls-authz OBJECT-ID' option to the qemu-nbd command which
takes the ID of a previously added 'QAuthZ' object instance. This will
be used to validate the client's x509 distinguished name. Clients
failing the authorization check will not be permitted to use the NBD
server.
For example to setup authorization that only allows connection from a client
whose x509 certificate distinguished name is
CN=laptop.example.com,O=Example Org,L=London,ST=London,C=GB
qemu-nbd --object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
--object authz-simple,id=auth0,identity=CN=laptop.example.com,,\
O=Example Org,,L=London,,ST=London,,C=GB \
Missing shell quoting around the space in 'Example Org'. It's also
fairly obvious that actual shell commands can't have leading space
between \-newline line continuations.
Post by Daniel P. Berrangé
--tls-creds tls0 \
--tls-authz authz0
....other qemu-nbd args...
---
include/block/nbd.h | 2 +-
nbd/server.c | 10 +++++-----
qemu-nbd.c | 13 ++++++++++++-
qemu-nbd.texi | 4 ++++
4 files changed, 22 insertions(+), 7 deletions(-)
+++ b/qemu-nbd.c
@@ -52,6 +52,7 @@
#define QEMU_NBD_OPT_TLSCREDS 261
#define QEMU_NBD_OPT_IMAGE_OPTS 262
#define QEMU_NBD_OPT_FORK 263
+#define QEMU_NBD_OPT_TLSAUTHZ 264
@@ -532,6 +534,7 @@ int main(int argc, char **argv)
{ "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
{ "trace", required_argument, NULL, 'T' },
{ "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
+ { "tls-authz", no_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
{ NULL, 0, NULL, 0 }
};
Missing a change to qemu-nbd --help to describe the new option.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
Daniel P. Berrangé
2018-11-15 10:35:26 UTC
Permalink
Post by Daniel P. Berrangé
Currently any client which can complete the TLS handshake is able to use
the NBD server. The server admin can turn on the 'verify-peer' option
for the x509 creds to require the client to provide a x509 certificate.
This means the client will have to acquire a certificate from the CA
before they are permitted to use the NBD server. This is still a fairly
low bar to cross.
This adds a '--tls-authz OBJECT-ID' option to the qemu-nbd command which
takes the ID of a previously added 'QAuthZ' object instance. This will
be used to validate the client's x509 distinguished name. Clients
failing the authorization check will not be permitted to use the NBD
server.
For example to setup authorization that only allows connection from a client
whose x509 certificate distinguished name is
CN=laptop.example.com,O=Example Org,L=London,ST=London,C=GB
qemu-nbd --object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
--object authz-simple,id=auth0,identity=CN=laptop.example.com,,\
O=Example Org,,L=London,,ST=London,,C=GB \
Missing shell quoting around the space in 'Example Org'. It's also fairly
obvious that actual shell commands can't have leading space between
\-newline line continuations.
Yep, leading space is the tradeoff of sticking to sensible line length
while maintaining clarity.
Post by Daniel P. Berrangé
--tls-creds tls0 \
--tls-authz authz0
....other qemu-nbd args...
---
include/block/nbd.h | 2 +-
nbd/server.c | 10 +++++-----
qemu-nbd.c | 13 ++++++++++++-
qemu-nbd.texi | 4 ++++
4 files changed, 22 insertions(+), 7 deletions(-)
+++ b/qemu-nbd.c
@@ -52,6 +52,7 @@
#define QEMU_NBD_OPT_TLSCREDS 261
#define QEMU_NBD_OPT_IMAGE_OPTS 262
#define QEMU_NBD_OPT_FORK 263
+#define QEMU_NBD_OPT_TLSAUTHZ 264
@@ -532,6 +534,7 @@ int main(int argc, char **argv)
{ "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
{ "trace", required_argument, NULL, 'T' },
{ "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
+ { "tls-authz", no_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
{ NULL, 0, NULL, 0 }
};
Missing a change to qemu-nbd --help to describe the new option.
Opps, yes.


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 :|
Daniel P. Berrangé
2018-11-15 10:47:02 UTC
Permalink
Post by Daniel P. Berrangé
Currently any client which can complete the TLS handshake is able to use
the NBD server. The server admin can turn on the 'verify-peer' option
for the x509 creds to require the client to provide a x509 certificate.
This means the client will have to acquire a certificate from the CA
before they are permitted to use the NBD server. This is still a fairly
low bar to cross.
This adds a '--tls-authz OBJECT-ID' option to the qemu-nbd command which
takes the ID of a previously added 'QAuthZ' object instance. This will
be used to validate the client's x509 distinguished name. Clients
failing the authorization check will not be permitted to use the NBD
server.
For example to setup authorization that only allows connection from a client
whose x509 certificate distinguished name is
CN=laptop.example.com,O=Example Org,L=London,ST=London,C=GB
qemu-nbd --object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
--object authz-simple,id=auth0,identity=CN=laptop.example.com,,\
O=Example Org,,L=London,,ST=London,,C=GB \
Missing shell quoting around the space in 'Example Org'. It's also fairly
obvious that actual shell commands can't have leading space between
\-newline line continuations.
Post by Daniel P. Berrangé
--tls-creds tls0 \
--tls-authz authz0
....other qemu-nbd args...
---
include/block/nbd.h | 2 +-
nbd/server.c | 10 +++++-----
qemu-nbd.c | 13 ++++++++++++-
qemu-nbd.texi | 4 ++++
4 files changed, 22 insertions(+), 7 deletions(-)
+++ b/qemu-nbd.c
@@ -52,6 +52,7 @@
#define QEMU_NBD_OPT_TLSCREDS 261
#define QEMU_NBD_OPT_IMAGE_OPTS 262
#define QEMU_NBD_OPT_FORK 263
+#define QEMU_NBD_OPT_TLSAUTHZ 264
@@ -532,6 +534,7 @@ int main(int argc, char **argv)
{ "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
{ "trace", required_argument, NULL, 'T' },
{ "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
+ { "tls-authz", no_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
{ NULL, 0, NULL, 0 }
};
Missing a change to qemu-nbd --help to describe the new option.
Yes, and it should be 'required_argument' too, not 'no_argument'.


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 :|
Daniel P. Berrangé
2018-10-09 13:23:26 UTC
Permalink
From: "Daniel P. Berrange" <***@redhat.com>

As with the previous patch to qemu-nbd, the nbd-server-start QMP command
also needs to be able to specify authorization when enabling TLS encryption.

First the client must create a QAuthZ object instance using the
'object-add' command:

{
'execute': 'object-add',
'arguments': {
'qom-type': 'authz-list',
'id': 'authz0',
'parameters': {
'policy': 'deny',
'rules': [
{
'match': '*CN=fred',
'policy': 'allow'
}
]
}
}
}

They can then reference this in the new 'tls-authz' parameter when
executing the 'nbd-server-start' command:

{
'execute': 'nbd-server-start',
'arguments': {
'addr': {
'type': 'inet',
'host': '127.0.0.1',
'port': '9000'
},
'tls-creds': 'tls0',
'tls-authz': 'authz0'
}
}

Signed-off-by: Daniel P. Berrange <***@redhat.com>
---
blockdev-nbd.c | 11 ++++++++---
hmp.c | 2 +-
include/block/nbd.h | 2 +-
qapi/block.json | 8 +++++++-
4 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 1d170c80b8..c10d6c0c81 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -23,6 +23,7 @@
typedef struct NBDServerData {
QIONetListener *listener;
QCryptoTLSCreds *tlscreds;
+ char *tlsauthz;
} NBDServerData;

static NBDServerData *nbd_server;
@@ -36,7 +37,7 @@ static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
gpointer opaque)
{
qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
- nbd_client_new(cioc, nbd_server->tlscreds, NULL,
+ nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz,
nbd_blockdev_client_closed);
}

@@ -52,6 +53,7 @@ static void nbd_server_free(NBDServerData *server)
if (server->tlscreds) {
object_unref(OBJECT(server->tlscreds));
}
+ g_free(server->tlsauthz);

g_free(server);
}
@@ -87,7 +89,7 @@ static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)


void nbd_server_start(SocketAddress *addr, const char *tls_creds,
- Error **errp)
+ const char *tls_authz, Error **errp)
{
if (nbd_server) {
error_setg(errp, "NBD server already running");
@@ -117,6 +119,8 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,
}
}

+ nbd_server->tlsauthz = g_strdup(tls_authz);
+
qio_net_listener_set_client_func(nbd_server->listener,
nbd_accept,
NULL,
@@ -131,11 +135,12 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,

void qmp_nbd_server_start(SocketAddressLegacy *addr,
bool has_tls_creds, const char *tls_creds,
+ bool has_tls_authz, const char *tls_authz,
Error **errp)
{
SocketAddress *addr_flat = socket_address_flatten(addr);

- nbd_server_start(addr_flat, tls_creds, errp);
+ nbd_server_start(addr_flat, tls_creds, tls_authz, errp);
qapi_free_SocketAddress(addr_flat);
}

diff --git a/hmp.c b/hmp.c
index 61ef120423..7fc5a6502f 100644
--- a/hmp.c
+++ b/hmp.c
@@ -2300,7 +2300,7 @@ void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
goto exit;
}

- nbd_server_start(addr, NULL, &local_err);
+ nbd_server_start(addr, NULL, NULL, &local_err);
qapi_free_SocketAddress(addr);
if (local_err != NULL) {
goto exit;
diff --git a/include/block/nbd.h b/include/block/nbd.h
index d7aa6b24d0..6cb336b45a 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -318,7 +318,7 @@ void nbd_client_get(NBDClient *client);
void nbd_client_put(NBDClient *client);

void nbd_server_start(SocketAddress *addr, const char *tls_creds,
- Error **errp);
+ const char *tls_authz, Error **errp);

void nbd_export_bitmap(NBDExport *exp, const char *bitmap,
const char *bitmap_export_name, Error **errp);
diff --git a/qapi/block.json b/qapi/block.json
index 11f01f28ef..812a9b1917 100644
--- a/qapi/block.json
+++ b/qapi/block.json
@@ -225,6 +225,11 @@
#
# @addr: Address on which to listen.
# @tls-creds: (optional) ID of the TLS credentials object. Since 2.6
+# @tls-authz: ID of the QAuthZ authorization object used to validate
+# the client's x509 distinguished name. This object is
+# is only resolved at time of use, so can be deleted and
+# recreated on the fly while the NBD server is active.
+# If missing, it will default to denying access. Since 3.1
#
# Returns: error if the server is already running.
#
@@ -232,7 +237,8 @@
##
{ 'command': 'nbd-server-start',
'data': { 'addr': 'SocketAddressLegacy',
- '*tls-creds': 'str'} }
+ '*tls-creds': 'str',
+ '*tls-authz': 'str'} }

##
# @nbd-server-add:
--
2.17.1
Juan Quintela
2018-10-17 12:28:53 UTC
Permalink
Post by Daniel P. Berrangé
As with the previous patch to qemu-nbd, the nbd-server-start QMP command
also needs to be able to specify authorization when enabling TLS encryption.
First the client must create a QAuthZ object instance using the
{
'execute': 'object-add',
'arguments': {
'qom-type': 'authz-list',
'id': 'authz0',
'parameters': {
'policy': 'deny',
'rules': [
{
'match': '*CN=fred',
'policy': 'allow'
}
]
}
}
}
They can then reference this in the new 'tls-authz' parameter when
{
'execute': 'nbd-server-start',
'arguments': {
'addr': {
'type': 'inet',
'host': '127.0.0.1',
'port': '9000'
},
'tls-creds': 'tls0',
'tls-authz': 'authz0'
}
}
Reviewed-by: Juan Quintela <***@redhat.com>

similar to previous patch in series.
Daniel P. Berrangé
2018-10-09 13:23:27 UTC
Permalink
From: "Daniel P. Berrange" <***@redhat.com>

The QEMU instance that runs as the server for the migration data
transport (ie the target QEMU) needs to be able to configure access
control so it can prevent unauthorized clients initiating an incoming
migration. This adds a new 'tls-authz' migration parameter that is used
to provide the QOM ID of a QAuthZ subclass instance that provides the
access control check. This is checked against the x509 certificate
obtained during the TLS handshake.

For example, when starting a QEMU for incoming migration, it is
possible to give an example identity of the source QEMU that is
intended to be connecting later:

$QEMU \
-monitor stdio \
-incoming defer \
...other args...

(qemu) object_add tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
(qemu) object_add authz-simple,id=auth0,identity=CN=laptop.example.com,,\
O=Example Org,,L=London,,ST=London,,C=GB \
(qemu) migrate_incoming tcp:localhost:9000

Signed-off-by: Daniel P. Berrange <***@redhat.com>
---
hmp.c | 9 +++++++++
migration/migration.c | 8 ++++++++
migration/tls.c | 2 +-
qapi/migration.json | 14 +++++++++++++-
4 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/hmp.c b/hmp.c
index 7fc5a6502f..52ee5e5444 100644
--- a/hmp.c
+++ b/hmp.c
@@ -396,6 +396,9 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
monitor_printf(mon, "%s: %" PRIu64 "\n",
MigrationParameter_str(MIGRATION_PARAMETER_MAX_POSTCOPY_BANDWIDTH),
params->max_postcopy_bandwidth);
+ monitor_printf(mon, " %s: '%s'\n",
+ MigrationParameter_str(MIGRATION_PARAMETER_TLS_AUTHZ),
+ params->has_tls_authz ? params->tls_authz : "");
}

qapi_free_MigrationParameters(params);
@@ -1702,6 +1705,12 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
p->tls_hostname->type = QTYPE_QSTRING;
visit_type_str(v, param, &p->tls_hostname->u.s, &err);
break;
+ case MIGRATION_PARAMETER_TLS_AUTHZ:
+ p->has_tls_authz = true;
+ p->tls_authz = g_new0(StrOrNull, 1);
+ p->tls_authz->type = QTYPE_QSTRING;
+ visit_type_str(v, param, &p->tls_authz->u.s, &err);
+ break;
case MIGRATION_PARAMETER_MAX_BANDWIDTH:
p->has_max_bandwidth = true;
/*
diff --git a/migration/migration.c b/migration/migration.c
index d6ae879dc8..f8d0251885 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -685,6 +685,8 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
params->tls_creds = g_strdup(s->parameters.tls_creds);
params->has_tls_hostname = true;
params->tls_hostname = g_strdup(s->parameters.tls_hostname);
+ params->has_tls_authz = true;
+ params->tls_authz = g_strdup(s->parameters.tls_authz);
params->has_max_bandwidth = true;
params->max_bandwidth = s->parameters.max_bandwidth;
params->has_downtime_limit = true;
@@ -1188,6 +1190,12 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
s->parameters.tls_hostname = g_strdup(params->tls_hostname->u.s);
}

+ if (params->has_tls_authz) {
+ g_free(s->parameters.tls_authz);
+ assert(params->tls_authz->type == QTYPE_QSTRING);
+ s->parameters.tls_authz = g_strdup(params->tls_authz->u.s);
+ }
+
if (params->has_max_bandwidth) {
s->parameters.max_bandwidth = params->max_bandwidth;
if (s->to_dst_file) {
diff --git a/migration/tls.c b/migration/tls.c
index 3b9e8c9263..5171afc6c4 100644
--- a/migration/tls.c
+++ b/migration/tls.c
@@ -94,7 +94,7 @@ void migration_tls_channel_process_incoming(MigrationState *s,

tioc = qio_channel_tls_new_server(
ioc, creds,
- NULL, /* XXX pass ACL name */
+ s->parameters.tls_authz,
errp);
if (!tioc) {
return;
diff --git a/qapi/migration.json b/qapi/migration.json
index 6e8c21258a..9c656effb0 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -519,6 +519,12 @@
# hostname must be provided so that the server's x509
# certificate identity can be validated. (Since 2.7)
#
+# @tls-authz: ID of the 'authz' object subclass that provides access control
+# checking of the TLS x509 certificate distinguished name.
+# This object is only resolved at time of use, so can be deleted
+# and recreated on the fly while the migration server is active.
+# If missing, it will default to denying access (Since 3.1)
+#
# @max-bandwidth: to set maximum speed for migration. maximum speed in
# bytes per second. (Since 2.8)
#
@@ -560,7 +566,7 @@
'data': ['compress-level', 'compress-threads', 'decompress-threads',
'compress-wait-thread',
'cpu-throttle-initial', 'cpu-throttle-increment',
- 'tls-creds', 'tls-hostname', 'max-bandwidth',
+ 'tls-creds', 'tls-hostname', 'tls-authz', 'max-bandwidth',
'downtime-limit', 'x-checkpoint-delay', 'block-incremental',
'x-multifd-channels', 'x-multifd-page-count',
'xbzrle-cache-size', 'max-postcopy-bandwidth',
@@ -658,6 +664,7 @@
'*cpu-throttle-increment': 'int',
'*tls-creds': 'StrOrNull',
'*tls-hostname': 'StrOrNull',
+ '*tls-authz': 'StrOrNull',
'*max-bandwidth': 'int',
'*downtime-limit': 'int',
'*x-checkpoint-delay': 'int',
@@ -727,6 +734,10 @@
# associated with the migration URI, if any. (Since 2.9)
# Note: 2.8 reports this by omitting tls-hostname instead.
#
+# @tls-authz: ID of the 'authz' object subclass that provides access control
+# checking of the TLS x509 certificate distinguished name. (Since
+# 3.1)
+#
# @max-bandwidth: to set maximum speed for migration. maximum speed in
# bytes per second. (Since 2.8)
#
@@ -774,6 +785,7 @@
'*cpu-throttle-increment': 'uint8',
'*tls-creds': 'str',
'*tls-hostname': 'str',
+ '*tls-authz': 'str',
'*max-bandwidth': 'size',
'*downtime-limit': 'uint64',
'*x-checkpoint-delay': 'uint32',
--
2.17.1
Juan Quintela
2018-10-17 12:30:24 UTC
Permalink
Post by Daniel P. Berrangé
The QEMU instance that runs as the server for the migration data
transport (ie the target QEMU) needs to be able to configure access
control so it can prevent unauthorized clients initiating an incoming
migration. This adds a new 'tls-authz' migration parameter that is used
to provide the QOM ID of a QAuthZ subclass instance that provides the
access control check. This is checked against the x509 certificate
obtained during the TLS handshake.
For example, when starting a QEMU for incoming migration, it is
possible to give an example identity of the source QEMU that is
$QEMU \
-monitor stdio \
-incoming defer \
...other args...
(qemu) object_add tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
(qemu) object_add authz-simple,id=auth0,identity=CN=laptop.example.com,,\
O=Example Org,,L=London,,ST=London,,C=GB \
(qemu) migrate_incoming tcp:localhost:9000
Reviewed-by: Juan Quintela <***@redhat.com>
Daniel P. Berrangé
2018-10-09 13:23:28 UTC
Permalink
From: "Daniel P. Berrange" <***@redhat.com>

Currently any client which can complete the TLS handshake is able to use
a chardev server. The server admin can turn on the 'verify-peer' option
for the x509 creds to require the client to provide a x509
certificate. This means the client will have to acquire a certificate
from the CA before they are permitted to use the chardev server. This is
still a fairly low bar.

This adds a 'tls-authz=OBJECT-ID' option to the socket chardev backend
which takes the ID of a previously added 'QAuthZ' object instance. This
will be used to validate the client's x509 distinguished name. Clients
failing the check will not be permitted to use the chardev server.

For example to setup authorization that only allows connection from a
client whose x509 certificate distinguished name contains 'CN=fred', you
would use:

$QEMU -object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
-object authz-simple,id=authz0,identity=CN=laptop.example.com,,\
O=Example Org,,L=London,,ST=London,,C=GB \
-chardev socket,host=127.0.0.1,port=9000,server,\
tls-creds=tls0,tls-authz=authz0 \
...other qemu args...

Signed-off-by: Daniel P. Berrange <***@redhat.com>
---
chardev/char-socket.c | 11 ++++++++++-
chardev/char.c | 3 +++
qapi/char.json | 6 ++++++
qemu-options.hx | 9 +++++++--
4 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index a75b46d9fe..ab121e1e30 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -52,6 +52,7 @@ typedef struct {
QIONetListener *listener;
GSource *hup_source;
QCryptoTLSCreds *tls_creds;
+ char *tls_authz;
int connected;
int max_size;
int do_telnetopt;
@@ -737,7 +738,7 @@ static void tcp_chr_tls_init(Chardev *chr)
if (s->is_listen) {
tioc = qio_channel_tls_new_server(
s->ioc, s->tls_creds,
- NULL, /* XXX Use an ACL */
+ s->tls_authz,
&err);
} else {
tioc = qio_channel_tls_new_client(
@@ -889,6 +890,7 @@ static void char_socket_finalize(Object *obj)
if (s->tls_creds) {
object_unref(OBJECT(s->tls_creds));
}
+ g_free(s->tls_authz);

qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
}
@@ -994,6 +996,7 @@ static void qmp_chardev_open_socket(Chardev *chr,
}
}
}
+ s->tls_authz = g_strdup(sock->tls_authz);

s->addr = addr = socket_address_flatten(sock->addr);

@@ -1075,6 +1078,7 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
const char *fd = qemu_opt_get(opts, "fd");
const char *tls_creds = qemu_opt_get(opts, "tls-creds");
SocketAddressLegacy *addr;
+ const char *tls_authz = qemu_opt_get(opts, "tls-authz");
ChardevSocket *sock;

if ((!!path + !!fd + !!host) != 1) {
@@ -1103,6 +1107,10 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
} else {
g_assert_not_reached();
}
+ if (tls_authz && !tls_creds) {
+ error_setg(errp, "Authorization can only be used when TLS is enabled");
+ return;
+ }

sock = backend->u.socket.data = g_new0(ChardevSocket, 1);
qemu_chr_parse_common(opts, qapi_ChardevSocket_base(sock));
@@ -1120,6 +1128,7 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
sock->has_reconnect = true;
sock->reconnect = reconnect;
sock->tls_creds = g_strdup(tls_creds);
+ sock->tls_authz = g_strdup(tls_authz);

addr = g_new0(SocketAddressLegacy, 1);
if (path) {
diff --git a/chardev/char.c b/chardev/char.c
index e115166995..987474a950 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -860,6 +860,9 @@ QemuOptsList qemu_chardev_opts = {
},{
.name = "tls-creds",
.type = QEMU_OPT_STRING,
+ },{
+ .name = "tls-authz",
+ .type = QEMU_OPT_STRING,
},{
.name = "width",
.type = QEMU_OPT_NUMBER,
diff --git a/qapi/char.json b/qapi/char.json
index b7b2a05766..244213c075 100644
--- a/qapi/char.json
+++ b/qapi/char.json
@@ -243,6 +243,11 @@
# @addr: socket address to listen on (server=true)
# or connect to (server=false)
# @tls-creds: the ID of the TLS credentials object (since 2.6)
+# @tls-authz: the ID of the QAuthZ authorization object against which
+# the client's x509 distinguished name will validated. This
+# object is only resolved at time of use, so can be deleted
+# and recreated on the fly while the chardev server is active.
+# If missing, it will default to denying access (since 3.1)
# @server: create server socket (default: true)
# @wait: wait for incoming connection on server
# sockets (default: false).
@@ -260,6 +265,7 @@
##
{ 'struct': 'ChardevSocket', 'data': { 'addr' : 'SocketAddressLegacy',
'*tls-creds' : 'str',
+ '*tls-authz' : 'str',
'*server' : 'bool',
'*wait' : 'bool',
'*nodelay' : 'bool',
diff --git a/qemu-options.hx b/qemu-options.hx
index cc61512db7..5079074088 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2410,7 +2410,7 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
"-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
"-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
" [,server][,nowait][,telnet][,reconnect=seconds][,mux=on|off]\n"
- " [,logfile=PATH][,logappend=on|off][,tls-creds=ID] (tcp)\n"
+ " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID], (tcp)\n"
"-chardev socket,id=id,path=path[,server][,nowait][,telnet][,reconnect=seconds]\n"
" [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
"-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
@@ -2539,7 +2539,7 @@ The available backends are:
A void device. This device will not emit any data, and will drop any data it
receives. The null backend does not take any options.

-@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,reconnect=@var{seconds}][,tls-creds=@var{id}]
+@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,reconnect=@var{seconds}][,tls-creds=@var{id}][,tls-authz=@var{id}]

Create a two-way stream socket, which can be either a TCP or a unix socket. A
unix socket will be created if @option{path} is specified. Behaviour is
@@ -2562,6 +2562,11 @@ and specifies the id of the TLS credentials to use for the handshake. The
credentials must be previously created with the @option{-object tls-creds}
argument.

+@option{tls-auth} provides the ID of the QAuthZ authorization object against
+which the client's x509 distinguished name will validated. This object is only
+resolved at time of use, so can be deleted and recreated on the fly while the
+chardev server is active. If missing, it will default to denying access.
+
TCP and unix socket options are given below:

@table @option
--
2.17.1
Juan Quintela
2018-10-17 12:32:17 UTC
Permalink
Post by Daniel P. Berrangé
Currently any client which can complete the TLS handshake is able to use
a chardev server. The server admin can turn on the 'verify-peer' option
for the x509 creds to require the client to provide a x509
certificate. This means the client will have to acquire a certificate
from the CA before they are permitted to use the chardev server. This is
still a fairly low bar.
This adds a 'tls-authz=OBJECT-ID' option to the socket chardev backend
which takes the ID of a previously added 'QAuthZ' object instance. This
will be used to validate the client's x509 distinguished name. Clients
failing the check will not be permitted to use the chardev server.
For example to setup authorization that only allows connection from a
client whose x509 certificate distinguished name contains 'CN=fred', you
$QEMU -object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
-object authz-simple,id=authz0,identity=CN=laptop.example.com,,\
O=Example Org,,L=London,,ST=London,,C=GB \
-chardev socket,host=127.0.0.1,port=9000,server,\
tls-creds=tls0,tls-authz=authz0 \
...other qemu args...
Reviewed-by: Juan Quintela <***@redhat.com>
Daniel P. Berrangé
2018-10-09 13:23:29 UTC
Permalink
From: "Daniel P. Berrange" <***@redhat.com>

The VNC server has historically had support for ACLs to check both the
SASL username and the TLS x509 distinguished name. The VNC server was
responsible for creating the initial ACL, and the client app was then
responsible for populating it with rules using the HMP 'acl_add' command.

This is not satisfactory for a variety of reasons. There is no way to
populate the ACLs from the command line, users are forced to use the
HMP. With multiple network services all supporting TLS and ACLs now, it
is desirable to be able to define a single ACL that is referenced by all
services.

To address these limitations, two new options are added to the VNC
server CLI. The 'tls-authz' option takes the ID of a QAuthZ object to
use for checking TLS x509 distinguished names, and the 'sasl-authz'
option takes the ID of another object to use for checking SASL usernames.

In this example, we setup two authorization rules. The first allows any
client with a certificate issued by the 'RedHat' organization in the
'London' locality. The second ACL allows clients with either the
'***@REDHAT.COM' or '***@REDHAT.COM' kerberos usernames. Both checks
must pass for the user to be allowed.

$QEMU -object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
-object authz-simple,id=authz0,policy=deny,\
rules.0.match=O=RedHat,,L=London,rules.0.policy=allow \
-object authz-simple,id=authz1,policy=deny,\
rules.0.match=***@REDHAT.COM,rules.0.policy=allow \
rules.0.match=***@REDHAT.COM,rules.0.policy=allow \
-vnc 0.0.0.0:1,tls-creds=tls0,tls-authz=authz0,
sasl,sasl-authz=authz1 \
...other QEMU args...

Signed-off-by: Daniel P. Berrange <***@redhat.com>
---
qemu-deprecated.texi | 5 ++++
qemu-options.hx | 35 ++++++++++++++++++--------
ui/vnc.c | 58 +++++++++++++++++++++++++++++++++++++-------
3 files changed, 79 insertions(+), 19 deletions(-)

diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
index 16ff946b55..d74d9ea02c 100644
--- a/qemu-deprecated.texi
+++ b/qemu-deprecated.texi
@@ -93,6 +93,11 @@ for these file types is 'host_cdrom' or 'host_device' as appropriate.
The @option{name} parameter of the @option{-net} option is a synonym
for the @option{id} parameter, which should now be used instead.

+@subsection -vnc acl (since 3.1.0)
+
+The @code{acl} option to the @code{-vnc} argument has been replaced
+by the @code{tls-authz} and @code{sasl-authz} options.
+
@section QEMU Machine Protocol (QMP) commands

@subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
diff --git a/qemu-options.hx b/qemu-options.hx
index 5079074088..6c3eef8b32 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1626,6 +1626,14 @@ will cause the VNC server socket to enable the VeNCrypt auth
mechanism. The credentials should have been previously created
using the @option{-object tls-creds} argument.

+@item tls-authz=@var{ID}
+
+Provides the ID of the QAuthZ authorization object against which
+the client's x509 distinguished name will validated. This object is
+only resolved at time of use, so can be deleted and recreated on the
+fly while the VNC server is active. If missing, it will default
+to denying access.
+
@item sasl

Require that the client use SASL to authenticate with the VNC server.
@@ -1641,18 +1649,25 @@ ensures a data encryption preventing compromise of authentication
credentials. See the @ref{vnc_security} section for details on using
SASL authentication.

+@item sasl-authz=@var{ID}
+
+Provides the ID of the QAuthZ authorization object against which
+the client's SASL username will validated. This object is
+only resolved at time of use, so can be deleted and recreated on the
+fly while the VNC server is active. If missing, it will default
+to denying access.
+
@item acl

-Turn on access control lists for checking of the x509 client certificate
-and SASL party. For x509 certs, the ACL check is made against the
-certificate's distinguished name. This is something that looks like
-@code{C=GB,O=ACME,L=Boston,CN=bob}. For SASL party, the ACL check is
-made against the username, which depending on the SASL plugin, may
-include a realm component, eg @code{bob} or @code{bob@@EXAMPLE.COM}.
-When the @option{acl} flag is set, the initial access list will be
-empty, with a @code{deny} policy. Thus no one will be allowed to
-use the VNC server until the ACLs have been loaded. This can be
-achieved using the @code{acl} monitor command.
+Legacy method for enabling authorization of clients against the
+x509 distinguished name and SASL username. It results in the creation
+of two @code{authz-list} objects with IDs of @code{vnc.username} and
+@code{vnc.x509dname}. The rules for these objects must be configured
+with the HMP ACL commands.
+
+This option is deprecated and should no longer be used. The new
+@option{sasl-authz} and @option{tls-authz} options are a
+replacement.

@item lossy

diff --git a/ui/vnc.c b/ui/vnc.c
index 60cb7c2d3d..8624b10e48 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -3395,6 +3395,12 @@ static QemuOptsList qemu_vnc_opts = {
},{
.name = "acl",
.type = QEMU_OPT_BOOL,
+ },{
+ .name = "tls-authz",
+ .type = QEMU_OPT_STRING,
+ },{
+ .name = "sasl-authz",
+ .type = QEMU_OPT_STRING,
},{
.name = "lossy",
.type = QEMU_OPT_BOOL,
@@ -3834,6 +3840,8 @@ void vnc_display_open(const char *id, Error **errp)
const char *credid;
bool sasl = false;
int acl = 0;
+ const char *tlsauthz;
+ const char *saslauthz;
int lock_key_sync = 1;
int key_delay_ms;

@@ -3905,7 +3913,33 @@ void vnc_display_open(const char *id, Error **errp)
goto fail;
}
}
+ if (qemu_opt_get(opts, "acl")) {
+ error_report("The 'acl' option to -vnc is deprecated. "
+ "Please use the 'tls-authz' and 'sasl-authz' "
+ "options instead");
+ }
acl = qemu_opt_get_bool(opts, "acl", false);
+ tlsauthz = qemu_opt_get(opts, "tls-authz");
+ if (acl && tlsauthz) {
+ error_setg(errp, "'acl' option is mutually exclusive with the "
+ "'tls-authz' option");
+ goto fail;
+ }
+ if (tlsauthz && !vd->tlscreds) {
+ error_setg(errp, "'tls-authz' provided but TLS is not enabled");
+ goto fail;
+ }
+
+ saslauthz = qemu_opt_get(opts, "sasl-authz");
+ if (acl && saslauthz) {
+ error_setg(errp, "'acl' option is mutually exclusive with the "
+ "'sasl-authz' option");
+ goto fail;
+ }
+ if (saslauthz && !sasl) {
+ error_setg(errp, "'sasl-authz' provided but SASL auth is not enabled");
+ goto fail;
+ }

share = qemu_opt_get(opts, "share");
if (share) {
@@ -3935,7 +3969,9 @@ void vnc_display_open(const char *id, Error **errp)
vd->non_adaptive = true;
}

- if (acl) {
+ if (tlsauthz) {
+ vd->tlsauthzid = g_strdup(tlsauthz);
+ } else if (acl) {
if (strcmp(vd->id, "default") == 0) {
vd->tlsauthzid = g_strdup("vnc.x509dname");
} else {
@@ -3946,15 +3982,19 @@ void vnc_display_open(const char *id, Error **errp)
&error_abort));
}
#ifdef CONFIG_VNC_SASL
- if (acl && sasl) {
- if (strcmp(vd->id, "default") == 0) {
- vd->sasl.authzid = g_strdup("vnc.username");
- } else {
- vd->sasl.authzid = g_strdup_printf("vnc.%s.username", vd->id);
+ if (sasl) {
+ if (saslauthz) {
+ vd->sasl.authzid = g_strdup(saslauthz);
+ } else if (acl) {
+ if (strcmp(vd->id, "default") == 0) {
+ vd->sasl.authzid = g_strdup("vnc.username");
+ } else {
+ vd->sasl.authzid = g_strdup_printf("vnc.%s.username", vd->id);
+ }
+ vd->sasl.authz = QAUTHZ(qauthz_list_new(vd->sasl.authzid,
+ QAUTHZ_LIST_POLICY_DENY,
+ &error_abort));
}
- vd->sasl.authz = QAUTHZ(qauthz_list_new(vd->sasl.authzid,
- QAUTHZ_LIST_POLICY_DENY,
- &error_abort));
}
#endif
--
2.17.1
Juan Quintela
2018-11-05 14:21:48 UTC
Permalink
Post by Daniel P. Berrangé
The VNC server has historically had support for ACLs to check both the
SASL username and the TLS x509 distinguished name. The VNC server was
responsible for creating the initial ACL, and the client app was then
responsible for populating it with rules using the HMP 'acl_add' command.
This is not satisfactory for a variety of reasons. There is no way to
populate the ACLs from the command line, users are forced to use the
HMP. With multiple network services all supporting TLS and ACLs now, it
is desirable to be able to define a single ACL that is referenced by all
services.
To address these limitations, two new options are added to the VNC
server CLI. The 'tls-authz' option takes the ID of a QAuthZ object to
use for checking TLS x509 distinguished names, and the 'sasl-authz'
option takes the ID of another object to use for checking SASL usernames.
In this example, we setup two authorization rules. The first allows any
client with a certificate issued by the 'RedHat' organization in the
'London' locality. The second ACL allows clients with either the
must pass for the user to be allowed.
$QEMU -object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
-object authz-simple,id=authz0,policy=deny,\
rules.0.match=O=RedHat,,L=London,rules.0.policy=allow \
-object authz-simple,id=authz1,policy=deny,\
-vnc 0.0.0.0:1,tls-creds=tls0,tls-authz=authz0,
sasl,sasl-authz=authz1 \
...other QEMU args...
Reviewed-by: Juan Quintela <***@redhat.com>
Daniel P. Berrangé
2018-10-09 13:23:30 UTC
Permalink
The various ACL related commands are obsolete now that the QAuthZ
framework for authorization is fully integrated throughout QEMU network
services. Mark it as deprecated with no replacement to be provided.

Authorization is now provided by using 'object_add' together with
the 'tls-authz' or 'sasl-authz' parameters to the VNC server, and
equivalent for other network services.

Signed-off-by: Daniel P. Berrangé <***@redhat.com>
---
monitor.c | 23 +++++++++++++++++++++++
qemu-deprecated.texi | 6 ++++++
2 files changed, 29 insertions(+)

diff --git a/monitor.c b/monitor.c
index abedc6263f..8144f304c4 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2056,6 +2056,19 @@ static QAuthZList *find_auth(Monitor *mon, const char *name)
return QAUTHZ_LIST(obj);
}

+static bool warn_acl;
+static void hmp_warn_acl(void)
+{
+ if (warn_acl) {
+ return;
+ }
+ error_report("The acl_show, acl_reset, acl_policy, acl_add, acl_remove "
+ "commands are deprecated with no replacement. Authorization "
+ "for VNC should be performed using the pluggable QAuthZ "
+ "objects");
+ warn_acl = true;
+}
+
static void hmp_acl_show(Monitor *mon, const QDict *qdict)
{
const char *aclname = qdict_get_str(qdict, "aclname");
@@ -2063,6 +2076,8 @@ static void hmp_acl_show(Monitor *mon, const QDict *qdict)
QAuthZListRuleList *rules;
size_t i = 0;

+ hmp_warn_acl();
+
if (!auth) {
return;
}
@@ -2086,6 +2101,8 @@ static void hmp_acl_reset(Monitor *mon, const QDict *qdict)
const char *aclname = qdict_get_str(qdict, "aclname");
QAuthZList *auth = find_auth(mon, aclname);

+ hmp_warn_acl();
+
if (!auth) {
return;
}
@@ -2104,6 +2121,8 @@ static void hmp_acl_policy(Monitor *mon, const QDict *qdict)
int val;
Error *err = NULL;

+ hmp_warn_acl();
+
if (!auth) {
return;
}
@@ -2139,6 +2158,8 @@ static void hmp_acl_add(Monitor *mon, const QDict *qdict)
QAuthZListFormat format;
size_t i = 0;

+ hmp_warn_acl();
+
if (!auth) {
return;
}
@@ -2194,6 +2215,8 @@ static void hmp_acl_remove(Monitor *mon, const QDict *qdict)
QAuthZList *auth = find_auth(mon, aclname);
ssize_t i = 0;

+ hmp_warn_acl();
+
if (!auth) {
return;
}
diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
index d74d9ea02c..dc6b1909e0 100644
--- a/qemu-deprecated.texi
+++ b/qemu-deprecated.texi
@@ -121,6 +121,12 @@ replaced by the ``target'' output member.
The @option{[hub_id name]} parameter tuple of the 'hostfwd_add' and
'hostfwd_remove' HMP commands has been replaced by @option{netdev_id}.

+@subsection acl_show, acl_reset, acl_policy, acl_add, acl_remove (since 3.1)
+
+The ``acl_show'', ``acl_reset'', ``acl_policy'', ``acl_add'', and
+``acl_remove'' commands are deprecated with no replacement. Authorization
+for VNC should be performed using the pluggable QAuthZ objects.
+
@section System emulator devices

@subsection ivshmem (since 2.6.0)
--
2.17.1
Juan Quintela
2018-11-05 14:22:50 UTC
Permalink
Post by Daniel P. Berrangé
The various ACL related commands are obsolete now that the QAuthZ
framework for authorization is fully integrated throughout QEMU network
services. Mark it as deprecated with no replacement to be provided.
Authorization is now provided by using 'object_add' together with
the 'tls-authz' or 'sasl-authz' parameters to the VNC server, and
equivalent for other network services.
Reviewed-by: Juan Quintela <***@redhat.com>
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