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char: introduce support for TLS encrypted TCP chardev backend 

This integrates support for QIOChannelTLS object in the TCP
chardev backend. If the 'tls-creds=NAME' option is passed with
the '-chardev tcp' argument, then it will setup the chardev
such that the client is required to establish a TLS handshake
when connecting. There is no support for checking the client
certificate against ACLs in this initial patch. This is pending
work to QOM-ify the ACL object code.

A complete invocation to run QEMU as the server for a TLS
encrypted serial dev might be

  $ qemu-system-x86_64 \
      -nodefconfig -nodefaults -device sga -display none \
      -chardev socket,id=s0,host=127.0.0.1,port=9000,tls-creds=tls0,server \
      -device isa-serial,chardev=s0 \
      -object tls-creds-x509,id=tls0,endpoint=server,verify-peer=off,\
         dir=/home/berrange/security/qemutls

To test with the gnutls-cli tool as the client:

  $ gnutls-cli --priority=NORMAL -p 9000 \
       --x509cafile=/home/berrange/security/qemutls/ca-cert.pem \
       127.0.0.1

If QEMU was told to use 'anon' credential type, then use the
priority string 'NORMAL:+ANON-DH' with gnutls-cli

Alternatively, if setting up a chardev to operate as a client,
then the TLS credentials registered must be for the client
endpoint. First a TLS server must be setup, which can be done
with the gnutls-serv tool

  $ gnutls-serv --priority=NORMAL -p 9000 --echo \
       --x509cafile=/home/berrange/security/qemutls/ca-cert.pem \
       --x509certfile=/home/berrange/security/qemutls/server-cert.pem \
       --x509keyfile=/home/berrange/security/qemutls/server-key.pem

Then QEMU can connect with

  $ qemu-system-x86_64 \
      -nodefconfig -nodefaults -device sga -display none \
      -chardev socket,id=s0,host=127.0.0.1,port=9000,tls-creds=tls0 \
      -device isa-serial,chardev=s0 \
      -object tls-creds-x509,id=tls0,endpoint=client,\
        dir=/home/berrange/security/qemutls

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1453202071-10289-5-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Daniel P. Berrange 2016-01-19 11:14:31 +00:00 committed by Paolo Bonzini
parent f2001a7e05
commit a8fb542705
3 changed files with 134 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
qapi-schema.json
View File

@ -3146,6 +3146,7 @@
#
# @addr: socket address to listen on (server=true)
# or connect to (server=false)
# @tls-creds: #optional the ID of the TLS credentials object (since 2.6)
# @server: #optional create server socket (default: true)
# @wait: #optional wait for incoming connection on server
# sockets (default: false).
@ -3160,6 +3161,7 @@
# Since: 1.4
##
{ 'struct': 'ChardevSocket', 'data': { 'addr' : 'SocketAddress',
'*tls-creds' : 'str',
'*server' : 'bool',
'*wait' : 'bool',
'*nodelay' : 'bool',

136
qemu-char.c
View File

@ -35,6 +35,7 @@
#include "qemu/base64.h"
#include "io/channel-socket.h"
#include "io/channel-file.h"
#include "io/channel-tls.h"
#include <unistd.h>
#include <fcntl.h>
@ -2532,9 +2533,11 @@ static CharDriverState *qemu_chr_open_udp(QIOChannelSocket *sioc,
/* TCP Net console */
typedef struct {
QIOChannel *ioc;
QIOChannel *ioc; /* Client I/O channel */
QIOChannelSocket *sioc; /* Client master channel */
QIOChannelSocket *listen_ioc;
guint listen_tag;
QCryptoTLSCreds *tls_creds;
int connected;
int max_size;
int do_telnetopt;
@ -2776,6 +2779,8 @@ static void tcp_chr_disconnect(CharDriverState *chr)
QIO_CHANNEL(s->listen_ioc), G_IO_IN, tcp_chr_accept, chr, NULL);
}
remove_fd_in_watch(chr);
object_unref(OBJECT(s->sioc));
s->sioc = NULL;
object_unref(OBJECT(s->ioc));
s->ioc = NULL;
g_free(chr->filename);
@ -2849,12 +2854,12 @@ static void tcp_chr_connect(void *opaque)
{
CharDriverState *chr = opaque;
TCPCharDriver *s = chr->opaque;
QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(s->ioc);
g_free(chr->filename);
chr->filename = sockaddr_to_str(&sioc->localAddr, sioc->localAddrLen,
&sioc->remoteAddr, sioc->remoteAddrLen,
s->is_listen, s->is_telnet);
chr->filename = sockaddr_to_str(
&s->sioc->localAddr, s->sioc->localAddrLen,
&s->sioc->remoteAddr, s->sioc->remoteAddrLen,
s->is_listen, s->is_telnet);
s->connected = 1;
if (s->ioc) {
@ -2943,6 +2948,57 @@ static void tcp_chr_telnet_init(CharDriverState *chr)
init, NULL);
}
static void tcp_chr_tls_handshake(Object *source,
Error *err,
gpointer user_data)
{
CharDriverState *chr = user_data;
TCPCharDriver *s = chr->opaque;
if (err) {
tcp_chr_disconnect(chr);
} else {
if (s->do_telnetopt) {
tcp_chr_telnet_init(chr);
} else {
tcp_chr_connect(chr);
}
}
}
static void tcp_chr_tls_init(CharDriverState *chr)
{
TCPCharDriver *s = chr->opaque;
QIOChannelTLS *tioc;
Error *err = NULL;
if (s->is_listen) {
tioc = qio_channel_tls_new_server(
s->ioc, s->tls_creds,
NULL, /* XXX Use an ACL */
&err);
} else {
tioc = qio_channel_tls_new_client(
s->ioc, s->tls_creds,
s->addr->u.inet->host,
&err);
}
if (tioc == NULL) {
error_free(err);
tcp_chr_disconnect(chr);
}
object_unref(OBJECT(s->ioc));
s->ioc = QIO_CHANNEL(tioc);
qio_channel_tls_handshake(tioc,
tcp_chr_tls_handshake,
chr,
NULL);
}
static int tcp_chr_new_client(CharDriverState *chr, QIOChannelSocket *sioc)
{
TCPCharDriver *s = chr->opaque;
@ -2952,6 +3008,8 @@ static int tcp_chr_new_client(CharDriverState *chr, QIOChannelSocket *sioc)
s->ioc = QIO_CHANNEL(sioc);
object_ref(OBJECT(sioc));
s->sioc = sioc;
object_ref(OBJECT(sioc));
if (s->do_nodelay) {
qio_channel_set_delay(s->ioc, false);
@ -2961,10 +3019,14 @@ static int tcp_chr_new_client(CharDriverState *chr, QIOChannelSocket *sioc)
s->listen_tag = 0;
}
if (s->do_telnetopt) {
tcp_chr_telnet_init(chr);
if (s->tls_creds) {
tcp_chr_tls_init(chr);
} else {
tcp_chr_connect(chr);
if (s->do_telnetopt) {
tcp_chr_telnet_init(chr);
} else {
tcp_chr_connect(chr);
}
}
return 0;
@ -3033,6 +3095,9 @@ static void tcp_chr_close(CharDriverState *chr)
}
g_free(s->read_msgfds);
}
if (s->tls_creds) {
object_unref(OBJECT(s->tls_creds));
}
if (s->write_msgfds_num) {
g_free(s->write_msgfds);
}
@ -3563,6 +3628,7 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
const char *path = qemu_opt_get(opts, "path");
const char *host = qemu_opt_get(opts, "host");
const char *port = qemu_opt_get(opts, "port");
const char *tls_creds = qemu_opt_get(opts, "tls-creds");
SocketAddress *addr;
if (!path) {
@ -3574,6 +3640,11 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
error_setg(errp, "chardev: socket: no port given");
return;
}
} else {
if (tls_creds) {
error_setg(errp, "TLS can only be used over TCP socket");
return;
}
}
backend->u.socket = g_new0(ChardevSocket, 1);
@ -3589,6 +3660,7 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
backend->u.socket->wait = is_waitconnect;
backend->u.socket->has_reconnect = true;
backend->u.socket->reconnect = reconnect;
backend->u.socket->tls_creds = g_strdup(tls_creds);
addr = g_new0(SocketAddress, 1);
if (path) {
@ -4015,6 +4087,9 @@ QemuOptsList qemu_chardev_opts = {
},{
.name = "telnet",
.type = QEMU_OPT_BOOL,
},{
.name = "tls-creds",
.type = QEMU_OPT_STRING,
},{
.name = "width",
.type = QEMU_OPT_NUMBER,
@ -4231,6 +4306,39 @@ static CharDriverState *qmp_chardev_open_socket(const char *id,
s->is_listen = is_listen;
s->is_telnet = is_telnet;
s->do_nodelay = do_nodelay;
if (sock->tls_creds) {
Object *creds;
creds = object_resolve_path_component(
object_get_objects_root(), sock->tls_creds);
if (!creds) {
error_setg(errp, "No TLS credentials with id '%s'",
sock->tls_creds);
goto error;
}
s->tls_creds = (QCryptoTLSCreds *)
object_dynamic_cast(creds,
TYPE_QCRYPTO_TLS_CREDS);
if (!s->tls_creds) {
error_setg(errp, "Object with id '%s' is not TLS credentials",
sock->tls_creds);
goto error;
}
object_ref(OBJECT(s->tls_creds));
if (is_listen) {
if (s->tls_creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
error_setg(errp, "%s",
"Expected TLS credentials for server endpoint");
goto error;
}
} else {
if (s->tls_creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
error_setg(errp, "%s",
"Expected TLS credentials for client endpoint");
goto error;
}
}
}
qapi_copy_SocketAddress(&s->addr, sock->addr);
chr->opaque = s;
@ -4259,9 +4367,7 @@ static CharDriverState *qmp_chardev_open_socket(const char *id,
if (s->reconnect_time) {
socket_try_connect(chr);
} else if (!qemu_chr_open_socket_fd(chr, errp)) {
g_free(s);
qemu_chr_free_common(chr);
return NULL;
goto error;
}
if (is_listen && is_waitconnect) {
@ -4272,6 +4378,14 @@ static CharDriverState *qmp_chardev_open_socket(const char *id,
}
return chr;
error:
if (s->tls_creds) {
object_unref(OBJECT(s->tls_creds));
}
g_free(s);
qemu_chr_free_common(chr);
return NULL;
}
static CharDriverState *qmp_chardev_open_udp(const char *id,

9
qemu-options.hx
View File

@ -2092,7 +2092,7 @@ 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] (tcp)\n"
" [,logfile=PATH][,logappend=on|off][,tls-creds=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"
@ -2172,7 +2172,7 @@ Further options to each backend are described below.
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}]
@item -chardev socket ,id=@var{id} [@var{TCP options} or @var{unix options}] [,server] [,nowait] [,telnet] [,reconnect=@var{seconds}] [,tls-creds=@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
@ -2190,6 +2190,11 @@ escape sequences.
the remote end goes away. qemu will delay this many seconds and then attempt
to reconnect. Zero disables reconnecting, and is the default.
@option{tls-creds} requests enablement of the TLS protocol for encryption,
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.
TCP and unix socket options are given below:
@table @option