nbd patches for 2019-03-08

- support TLS client authorization in NBD servers
 - iotest 223 race fix
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Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2019-03-08' into staging

nbd patches for 2019-03-08

- support TLS client authorization in NBD servers
- iotest 223 race fix

# gpg: Signature made Fri 08 Mar 2019 17:37:59 GMT
# gpg:                using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full]
# gpg:                 aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2019-03-08:
  iotests: Wait for qemu to end in 223
  nbd: fix outdated qapi docs syntax for tls-creds
  nbd: allow authorization with nbd-server-start QMP command
  qemu-nbd: add support for authorization of TLS clients

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

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);
 }
 

hmp.c

@@ -2373,7 +2373,7 @@ 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;

include/block/nbd.h

@@ -326,13 +326,13 @@ 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);
 
 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
-                      Error **errp);
+                      const char *tls_authz, Error **errp);
 
 /* nbd_read
  * Reads @size bytes from @ioc. Returns 0 on success.

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) */
 
@@ -686,7 +686,7 @@ 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;
@@ -1348,7 +1348,7 @@ 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);
@@ -2425,7 +2425,7 @@ 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;
@@ -2437,7 +2437,7 @@ 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);

qapi/block.json

@@ -224,7 +224,12 @@
 # QEMU instance could refer to them as "nbd:HOST:PORT:exportname=NAME".
 #
 # @addr: Address on which to listen.
-# @tls-creds: (optional) ID of the TLS credentials object. Since 2.6
+# @tls-creds: 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 4.0).
 #
 # 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:

qemu-nbd.c

@@ -58,6 +58,7 @@
 #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
 
@@ -71,6 +72,7 @@ static int shared = 1;
 static int nb_fds;
 static QIONetListener *server;
 static QCryptoTLSCreds *tlscreds;
+static const char *tlsauthz;
 
 static void usage(const char *name)
 {
@@ -103,6 +105,8 @@ static void usage(const char *name)
 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
 "                            passwords and/or encryption keys\n"
 "  --tls-creds=ID            use id of an earlier --object to provide TLS\n"
+"  --tls-authz=ID            use id of an earlier --object to provide\n"
+"                            authorization\n"
 "  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
 "                            specify tracing options\n"
 "  --fork                    fork off the server process and exit the parent\n"
@@ -452,7 +456,7 @@ 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)
@@ -643,6 +647,7 @@ int main(int argc, char **argv)
         { "export-name", required_argument, NULL, 'x' },
         { "description", required_argument, NULL, 'D' },
         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
+        { "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
         { "trace", required_argument, NULL, 'T' },
         { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },
@@ -862,6 +867,9 @@ 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;
@@ -934,12 +942,21 @@ int main(int argc, char **argv)
             error_report("TLS is not supported with a host device");
             exit(EXIT_FAILURE);
         }
+        if (tlsauthz && list) {
+            error_report("TLS authorization is incompatible with export list");
+            exit(EXIT_FAILURE);
+        }
         tlscreds = nbd_get_tls_creds(tlscredsid, list, &local_err);
         if (local_err) {
             error_report("Failed to get TLS creds %s",
                          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 (list) {

qemu-nbd.texi

@@ -117,6 +117,10 @@ option; or provide the credentials needed for connecting as a client
 in list mode.
 @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
@@ -142,13 +146,16 @@ qemu-nbd -f qcow2 file.qcow2
 @end example
 
 Start a long-running server listening with encryption on port 10810,
-and require clients to have a correct X.509 certificate to connect to
+and whitelist clients with a specific X.509 certificate to connect to
 a 1 megabyte subset of a raw file, using the export name 'subset':
 
 @example
 qemu-nbd \
   --object tls-creds-x509,id=tls0,endpoint=server,dir=/path/to/qemutls \
-  --tls-creds tls0 -t -x subset -p 10810 \
+  --object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,\
+            O=Example Org,,L=London,,ST=London,,C=GB' \
+  --tls-creds tls0 --tls-authz auth0 \
+  -t -x subset -p 10810 \
   --image-opts driver=raw,offset=1M,size=1M,file.driver=file,file.filename=file.raw
 @end example
 

tests/qemu-iotests/223

@@ -179,6 +179,7 @@ _send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-remove",
 _send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-stop"}' "return"
 _send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-stop"}' "error" # Again
 _send_qemu_cmd $QEMU_HANDLE '{"execute":"quit"}' "return"
+wait=yes _cleanup_qemu
 
 echo
 echo "=== Use qemu-nbd as server ==="

tests/qemu-iotests/223.out

@@ -89,6 +89,7 @@ read 2097152/2097152 bytes at offset 2097152
 {"return": {}}
 {"error": {"class": "GenericError", "desc": "NBD server not running"}}
 {"return": {}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
 
 === Use qemu-nbd as server ===
 

tests/qemu-iotests/233

@@ -61,6 +61,7 @@ tls_x509_create_root_ca "ca2"
 tls_x509_create_server "ca1" "server1"
 tls_x509_create_client "ca1" "client1"
 tls_x509_create_client "ca2" "client2"
+tls_x509_create_client "ca1" "client3"
 
 echo
 echo "== preparing image =="
@@ -93,11 +94,15 @@ $QEMU_NBD_PROG -L -b $nbd_tcp_addr -p $nbd_tcp_port
 
 echo
 echo "== check TLS works =="
-obj=tls-creds-x509,dir=${tls_dir}/client1,endpoint=client,id=tls0
+obj1=tls-creds-x509,dir=${tls_dir}/client1,endpoint=client,id=tls0
-$QEMU_IMG info --image-opts --object $obj \
+obj2=tls-creds-x509,dir=${tls_dir}/client3,endpoint=client,id=tls0
+$QEMU_IMG info --image-opts --object $obj1 \
     driver=nbd,host=$nbd_tcp_addr,port=$nbd_tcp_port,tls-creds=tls0 \
     2>&1 | sed "s/$nbd_tcp_port/PORT/g"
-$QEMU_NBD_PROG -L -b $nbd_tcp_addr -p $nbd_tcp_port --object $obj \
+$QEMU_IMG info --image-opts --object $obj2 \
+    driver=nbd,host=$nbd_tcp_addr,port=$nbd_tcp_port,tls-creds=tls0 \
+    2>&1 | sed "s/$nbd_tcp_port/PORT/g"
+$QEMU_NBD_PROG -L -b $nbd_tcp_addr -p $nbd_tcp_port --object $obj1 \
     --tls-creds=tls0
 
 echo
@@ -119,6 +124,27 @@ $QEMU_IO -c 'r -P 0x11 1m 1m' -c 'w -P 0x22 1m 1m' --image-opts \
 
 $QEMU_IO -f $IMGFMT -r -U -c 'r -P 0x22 1m 1m' "$TEST_IMG" | _filter_qemu_io
 
+echo
+echo "== check TLS with authorization =="
+
+nbd_server_stop
+
+nbd_server_start_tcp_socket \
+    --object tls-creds-x509,dir=${tls_dir}/server1,endpoint=server,id=tls0,verify-peer=yes \
+    --object "authz-simple,id=authz0,identity=CN=localhost,, \
+      O=Cthulu Dark Lord Enterprises client1,,L=R'lyeh,,C=South Pacific" \
+    --tls-authz authz0 \
+    --tls-creds tls0 \
+    -f $IMGFMT "$TEST_IMG" 2>> "$TEST_DIR/server.log"
+
+$QEMU_IMG info --image-opts \
+    --object tls-creds-x509,dir=${tls_dir}/client1,endpoint=client,id=tls0 \
+    driver=nbd,host=$nbd_tcp_addr,port=$nbd_tcp_port,tls-creds=tls0
+
+$QEMU_IMG info --image-opts \
+    --object tls-creds-x509,dir=${tls_dir}/client3,endpoint=client,id=tls0 \
+    driver=nbd,host=$nbd_tcp_addr,port=$nbd_tcp_port,tls-creds=tls0
+
 echo
 echo "== final server log =="
 cat "$TEST_DIR/server.log"

tests/qemu-iotests/233.out

@@ -6,6 +6,7 @@ Generating a self signed certificate...
 Generating a signed certificate...
 Generating a signed certificate...
 Generating a signed certificate...
+Generating a signed certificate...
 
 == preparing image ==
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
@@ -29,6 +30,10 @@ image: nbd://127.0.0.1:PORT
 file format: nbd
 virtual size: 64M (67108864 bytes)
 disk size: unavailable
+image: nbd://127.0.0.1:PORT
+file format: nbd
+virtual size: 64M (67108864 bytes)
+disk size: unavailable
 exports available: 1
  export: ''
   size:  67108864
@@ -51,7 +56,13 @@ wrote 1048576/1048576 bytes at offset 1048576
 read 1048576/1048576 bytes at offset 1048576
 1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
+== check TLS with authorization ==
+qemu-img: Could not open 'driver=nbd,host=127.0.0.1,port=10809,tls-creds=tls0': Failed to read option reply: Cannot read from TLS channel: Software caused connection abort
+qemu-img: Could not open 'driver=nbd,host=127.0.0.1,port=10809,tls-creds=tls0': Failed to read option reply: Cannot read from TLS channel: Software caused connection abort
+
 == final server log ==
 qemu-nbd: option negotiation failed: Verify failed: No certificate was found.
 qemu-nbd: option negotiation failed: Verify failed: No certificate was found.
+qemu-nbd: option negotiation failed: TLS x509 authz check for CN=localhost,O=Cthulhu Dark Lord Enterprises client1,L=R'lyeh,C=South Pacific is denied
+qemu-nbd: option negotiation failed: TLS x509 authz check for CN=localhost,O=Cthulhu Dark Lord Enterprises client3,L=R'lyeh,C=South Pacific is denied
 *** done