On 10/9/18 8:23 AM, Daniel P. Berrangé wrote:
From: "Daniel P. Berrange" <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 \
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.
--tls-creds tls0 \ --tls-authz authz0 ....other qemu-nbd args...
Signed-off-by: Daniel P. Berrange <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(-)
+++ 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