[1/1] chardev: add support for authorization for TLS clients
diff mbox series

Message ID 20190227135523.16952-2-berrange@redhat.com
State New
Headers show
Series
  • chardev: support for authorization control on TLS connections
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Commit Message

Daniel P. Berrangé Feb. 27, 2019, 1:55 p.m. UTC
From: "Daniel P. Berrange" <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 <berrange@redhat.com>
---
 chardev/char-socket.c | 12 +++++++++++-
 chardev/char.c        |  3 +++
 qapi/char.json        |  6 ++++++
 qemu-options.hx       |  9 +++++++--
 4 files changed, 27 insertions(+), 3 deletions(-)

Comments

Philippe Mathieu-Daudé Feb. 27, 2019, 2:29 p.m. UTC | #1
On 2/27/19 2:55 PM, Daniel P. Berrangé wrote:
> From: "Daniel P. Berrange" <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 <berrange@redhat.com>
> ---
>  chardev/char-socket.c | 12 +++++++++++-
>  chardev/char.c        |  3 +++
>  qapi/char.json        |  6 ++++++
>  qemu-options.hx       |  9 +++++++--
>  4 files changed, 27 insertions(+), 3 deletions(-)
> 
> diff --git a/chardev/char-socket.c b/chardev/char-socket.c
> index 4fcdd8aedd..12e78426aa 100644
> --- a/chardev/char-socket.c
> +++ b/chardev/char-socket.c
> @@ -59,6 +59,7 @@ typedef struct {
>      QIONetListener *listener;
>      GSource *hup_source;
>      QCryptoTLSCreds *tls_creds;
> +    char *tls_authz;
>      TCPChardevState state;
>      int max_size;
>      int do_telnetopt;
> @@ -807,7 +808,7 @@ 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(
> @@ -1055,6 +1056,7 @@ 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);
>  }
> @@ -1242,6 +1244,11 @@ static bool qmp_chardev_validate_socket(ChardevSocket *sock,
>          break;
>      }
>  
> +    if (sock->has_tls_authz && !sock->has_tls_creds) {
> +        error_setg(errp, "'tls_authz' option requires 'tls_creds' option");
> +        return false;
> +    }
> +
>      /* Validate any options which have a dependancy on client vs server */
>      if (!sock->has_server || sock->server) {
>          if (sock->has_reconnect) {
> @@ -1320,6 +1327,7 @@ static void qmp_chardev_open_socket(Chardev *chr,
>              }
>          }
>      }
> +    s->tls_authz = g_strdup(sock->tls_authz);
>  
>      s->addr = addr = socket_address_flatten(sock->addr);
>  
> @@ -1399,6 +1407,8 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
>      sock->reconnect = qemu_opt_get_number(opts, "reconnect", 0);
>      sock->has_tls_creds = qemu_opt_get(opts, "tls-creds");
>      sock->tls_creds = g_strdup(qemu_opt_get(opts, "tls-creds"));
> +    sock->has_tls_authz = qemu_opt_get(opts, "tls-authz");
> +    sock->tls_authz = g_strdup(qemu_opt_get(opts, "tls-authz"));
>  
>      addr = g_new0(SocketAddressLegacy, 1);
>      if (path) {
> diff --git a/chardev/char.c b/chardev/char.c
> index f6d61fa5f8..514cd6b0c3 100644
> --- a/chardev/char.c
> +++ b/chardev/char.c
> @@ -880,6 +880,9 @@ QemuOptsList qemu_chardev_opts = {
>          },{
>              .name = "tls-creds",
>              .type = QEMU_OPT_STRING,
> +        },{
> +            .name = "tls-authz",
> +            .type = QEMU_OPT_STRING,
>          },{
>              .name = "websocket",
>              .type = QEMU_OPT_BOOL,
> diff --git a/qapi/char.json b/qapi/char.json
> index 77ed847972..7847c98d05 100644
> --- a/qapi/char.json
> +++ b/qapi/char.json
> @@ -248,6 +248,11 @@
>  # @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 4.0)
>  # @server: create server socket (default: true)
>  # @wait: wait for incoming connection on server
>  #        sockets (default: false).
> @@ -268,6 +273,7 @@
>  { '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 1cf9aac1fe..aecbb2ca9c 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -2413,7 +2413,7 @@ 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][,websocket][,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][,websocket][,reconnect=seconds]\n"
>      "         [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
>      "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
> @@ -2542,7 +2542,7 @@ 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][,websocket][,reconnect=@var{seconds}][,tls-creds=@var{id}]
> +@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,websocket][,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
> @@ -2568,6 +2568,11 @@ 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
> 

LGTM:
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Marc-André Lureau March 7, 2019, 6:51 p.m. UTC | #2
Hi

On Wed, Feb 27, 2019 at 2:55 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
>
> From: "Daniel P. Berrange" <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 <berrange@redhat.com>
> ---
>  chardev/char-socket.c | 12 +++++++++++-
>  chardev/char.c        |  3 +++
>  qapi/char.json        |  6 ++++++
>  qemu-options.hx       |  9 +++++++--
>  4 files changed, 27 insertions(+), 3 deletions(-)
>
> diff --git a/chardev/char-socket.c b/chardev/char-socket.c
> index 4fcdd8aedd..12e78426aa 100644
> --- a/chardev/char-socket.c
> +++ b/chardev/char-socket.c
> @@ -59,6 +59,7 @@ typedef struct {
>      QIONetListener *listener;
>      GSource *hup_source;
>      QCryptoTLSCreds *tls_creds;
> +    char *tls_authz;
>      TCPChardevState state;
>      int max_size;
>      int do_telnetopt;
> @@ -807,7 +808,7 @@ 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(
> @@ -1055,6 +1056,7 @@ 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);
>  }
> @@ -1242,6 +1244,11 @@ static bool qmp_chardev_validate_socket(ChardevSocket *sock,
>          break;
>      }
>
> +    if (sock->has_tls_authz && !sock->has_tls_creds) {
> +        error_setg(errp, "'tls_authz' option requires 'tls_creds' option");
> +        return false;
> +    }
> +
>      /* Validate any options which have a dependancy on client vs server */
>      if (!sock->has_server || sock->server) {
>          if (sock->has_reconnect) {
> @@ -1320,6 +1327,7 @@ static void qmp_chardev_open_socket(Chardev *chr,
>              }
>          }
>      }
> +    s->tls_authz = g_strdup(sock->tls_authz);
>
>      s->addr = addr = socket_address_flatten(sock->addr);
>
> @@ -1399,6 +1407,8 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
>      sock->reconnect = qemu_opt_get_number(opts, "reconnect", 0);
>      sock->has_tls_creds = qemu_opt_get(opts, "tls-creds");
>      sock->tls_creds = g_strdup(qemu_opt_get(opts, "tls-creds"));
> +    sock->has_tls_authz = qemu_opt_get(opts, "tls-authz");
> +    sock->tls_authz = g_strdup(qemu_opt_get(opts, "tls-authz"));
>
>      addr = g_new0(SocketAddressLegacy, 1);
>      if (path) {
> diff --git a/chardev/char.c b/chardev/char.c
> index f6d61fa5f8..514cd6b0c3 100644
> --- a/chardev/char.c
> +++ b/chardev/char.c
> @@ -880,6 +880,9 @@ QemuOptsList qemu_chardev_opts = {
>          },{
>              .name = "tls-creds",
>              .type = QEMU_OPT_STRING,
> +        },{
> +            .name = "tls-authz",
> +            .type = QEMU_OPT_STRING,
>          },{
>              .name = "websocket",
>              .type = QEMU_OPT_BOOL,
> diff --git a/qapi/char.json b/qapi/char.json
> index 77ed847972..7847c98d05 100644
> --- a/qapi/char.json
> +++ b/qapi/char.json
> @@ -248,6 +248,11 @@
>  # @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

will be? (not a native speaker, but sounds weird to me)

> +#             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 4.0)
>  # @server: create server socket (default: true)
>  # @wait: wait for incoming connection on server
>  #        sockets (default: false).
> @@ -268,6 +273,7 @@
>  { '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 1cf9aac1fe..aecbb2ca9c 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -2413,7 +2413,7 @@ 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][,websocket][,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][,websocket][,reconnect=seconds]\n"
>      "         [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
>      "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
> @@ -2542,7 +2542,7 @@ 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][,websocket][,reconnect=@var{seconds}][,tls-creds=@var{id}]
> +@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,websocket][,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
> @@ -2568,6 +2568,11 @@ 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

same

> +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.

Why not have "(since 4.0)"  here?

> +
>  TCP and unix socket options are given below:
>
>  @table @option
> --
> 2.20.1
>

Other than that,
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Eric Blake March 7, 2019, 7 p.m. UTC | #3
On 3/7/19 12:51 PM, Marc-André Lureau wrote:
> Hi
> 

>> +++ b/qapi/char.json
>> @@ -248,6 +248,11 @@
>>  # @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
> 
> will be? (not a native speaker, but sounds weird to me)

Yes, 'be' is missing.


>> @@ -2568,6 +2568,11 @@ 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
> 
> same
> 
>> +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.
> 
> Why not have "(since 4.0)"  here?

We haven't been using it in .hx doc anywhere else (which in turn feeds
the man page and online documentation); only the QMP descriptions have
used the tag. Uniformly using it in the .hx file might make sense, but
as a much bigger cleanup task separate from this patch that just
preserves existing style.

Patch
diff mbox series

diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index 4fcdd8aedd..12e78426aa 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -59,6 +59,7 @@  typedef struct {
     QIONetListener *listener;
     GSource *hup_source;
     QCryptoTLSCreds *tls_creds;
+    char *tls_authz;
     TCPChardevState state;
     int max_size;
     int do_telnetopt;
@@ -807,7 +808,7 @@  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(
@@ -1055,6 +1056,7 @@  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);
 }
@@ -1242,6 +1244,11 @@  static bool qmp_chardev_validate_socket(ChardevSocket *sock,
         break;
     }
 
+    if (sock->has_tls_authz && !sock->has_tls_creds) {
+        error_setg(errp, "'tls_authz' option requires 'tls_creds' option");
+        return false;
+    }
+
     /* Validate any options which have a dependancy on client vs server */
     if (!sock->has_server || sock->server) {
         if (sock->has_reconnect) {
@@ -1320,6 +1327,7 @@  static void qmp_chardev_open_socket(Chardev *chr,
             }
         }
     }
+    s->tls_authz = g_strdup(sock->tls_authz);
 
     s->addr = addr = socket_address_flatten(sock->addr);
 
@@ -1399,6 +1407,8 @@  static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
     sock->reconnect = qemu_opt_get_number(opts, "reconnect", 0);
     sock->has_tls_creds = qemu_opt_get(opts, "tls-creds");
     sock->tls_creds = g_strdup(qemu_opt_get(opts, "tls-creds"));
+    sock->has_tls_authz = qemu_opt_get(opts, "tls-authz");
+    sock->tls_authz = g_strdup(qemu_opt_get(opts, "tls-authz"));
 
     addr = g_new0(SocketAddressLegacy, 1);
     if (path) {
diff --git a/chardev/char.c b/chardev/char.c
index f6d61fa5f8..514cd6b0c3 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -880,6 +880,9 @@  QemuOptsList qemu_chardev_opts = {
         },{
             .name = "tls-creds",
             .type = QEMU_OPT_STRING,
+        },{
+            .name = "tls-authz",
+            .type = QEMU_OPT_STRING,
         },{
             .name = "websocket",
             .type = QEMU_OPT_BOOL,
diff --git a/qapi/char.json b/qapi/char.json
index 77ed847972..7847c98d05 100644
--- a/qapi/char.json
+++ b/qapi/char.json
@@ -248,6 +248,11 @@ 
 # @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 4.0)
 # @server: create server socket (default: true)
 # @wait: wait for incoming connection on server
 #        sockets (default: false).
@@ -268,6 +273,7 @@ 
 { '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 1cf9aac1fe..aecbb2ca9c 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2413,7 +2413,7 @@  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][,websocket][,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][,websocket][,reconnect=seconds]\n"
     "         [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
     "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
@@ -2542,7 +2542,7 @@  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][,websocket][,reconnect=@var{seconds}][,tls-creds=@var{id}]
+@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,websocket][,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
@@ -2568,6 +2568,11 @@  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