[Qemu-devel] [PATCH v1 RFC 18/34] ui: convert VNC websockets to use crypto APIs

["Daniel P. Berrange" <berrange@redhat.com>]

Remove the direct use of gnutls for hash processing in the
websockets code, in favour of using the crypto APIs. This
allows the websockets code to be built unconditionally
removing countless conditional checks from the VNC code.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 configure        | 19 +--------------
 ui/Makefile.objs |  2 +-
 ui/vnc-ws.c      | 22 ++++++++----------
 ui/vnc-ws.h      |  2 --
 ui/vnc.c         | 70 ++++++++++++--------------------------------------------
 ui/vnc.h         |  8 -------
 6 files changed, 26 insertions(+), 97 deletions(-)

diff --git a/configure b/configure
index afca51e..fa07f2c 100755
--- a/configure
+++ b/configure
@@ -245,7 +245,6 @@ vnc_tls=""
 vnc_sasl=""
 vnc_jpeg=""
 vnc_png=""
-vnc_ws=""
 xen=""
 xen_ctrl_version=""
 xen_pci_passthrough=""
@@ -889,10 +888,6 @@ for opt do
   ;;
   --enable-vnc-png) vnc_png="yes"
   ;;
-  --disable-vnc-ws) vnc_ws="no"
-  ;;
-  --enable-vnc-ws) vnc_ws="yes"
-  ;;
   --disable-slirp) slirp="no"
   ;;
   --disable-uuid) uuid="no"
@@ -2376,7 +2371,7 @@ fi
 
 ##########################################
 # VNC TLS/WS detection
-if test "$vnc" = "yes" -a \( "$vnc_tls" != "no" -o "$vnc_ws" != "no" \) ; then
+if test "$vnc" = "yes" -a "$vnc_tls" != "no" ; then
   cat > $TMPC <<EOF
 #include <gnutls/gnutls.h>
 int main(void) { gnutls_session_t s; gnutls_init(&s, GNUTLS_SERVER); return 0; }
@@ -2387,20 +2382,13 @@ EOF
     if test "$vnc_tls" != "no" ; then
       vnc_tls=yes
     fi
-    if test "$vnc_ws" != "no" ; then
-      vnc_ws=yes
-    fi
     libs_softmmu="$vnc_tls_libs $libs_softmmu"
     QEMU_CFLAGS="$QEMU_CFLAGS $vnc_tls_cflags"
   else
     if test "$vnc_tls" = "yes" ; then
       feature_not_found "vnc-tls" "Install gnutls devel"
     fi
-    if test "$vnc_ws" = "yes" ; then
-      feature_not_found "vnc-ws" "Install gnutls devel"
-    fi
     vnc_tls=no
-    vnc_ws=no
   fi
 fi
 
@@ -4448,7 +4436,6 @@ if test "$vnc" = "yes" ; then
     echo "VNC SASL support  $vnc_sasl"
     echo "VNC JPEG support  $vnc_jpeg"
     echo "VNC PNG support   $vnc_png"
-    echo "VNC WS support    $vnc_ws"
 fi
 if test -n "$sparc_cpu"; then
     echo "Target Sparc Arch $sparc_cpu"
@@ -4653,10 +4640,6 @@ fi
 if test "$vnc_png" = "yes" ; then
   echo "CONFIG_VNC_PNG=y" >> $config_host_mak
 fi
-if test "$vnc_ws" = "yes" ; then
-  echo "CONFIG_VNC_WS=y" >> $config_host_mak
-  echo "VNC_WS_CFLAGS=$vnc_ws_cflags" >> $config_host_mak
-fi
 if test "$fnmatch" = "yes" ; then
   echo "CONFIG_FNMATCH=y" >> $config_host_mak
 fi
diff --git a/ui/Makefile.objs b/ui/Makefile.objs
index ca3ca38..6458d3c 100644
--- a/ui/Makefile.objs
+++ b/ui/Makefile.objs
@@ -4,7 +4,7 @@ vnc-obj-y += vnc-enc-tight.o vnc-palette.o
 vnc-obj-y += vnc-enc-zrle.o
 vnc-obj-$(CONFIG_VNC_TLS) += vnc-tls.o vnc-auth-vencrypt.o
 vnc-obj-$(CONFIG_VNC_SASL) += vnc-auth-sasl.o
-vnc-obj-$(CONFIG_VNC_WS) += vnc-ws.o
+vnc-obj-y += vnc-ws.o
 vnc-obj-y += vnc-jobs.o
 
 common-obj-y += keymaps.o console.o cursor.o qemu-pixman.o
diff --git a/ui/vnc-ws.c b/ui/vnc-ws.c
index 62eb97f..93a7b35 100644
--- a/ui/vnc-ws.c
+++ b/ui/vnc-ws.c
@@ -20,6 +20,7 @@
 
 #include "vnc.h"
 #include "qemu/main-loop.h"
+#include "crypto/hash.h"
 
 #ifdef CONFIG_VNC_TLS
 #include "qemu/sockets.h"
@@ -203,24 +204,21 @@ static char *vncws_extract_handshake_entry(const char *handshake,
 static void vncws_send_handshake_response(VncState *vs, const char* key)
 {
     char combined_key[WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1];
-    unsigned char hash[SHA1_DIGEST_LEN];
-    size_t hash_size = sizeof(hash);
     char *accept = NULL, *response = NULL;
-    gnutls_datum_t in;
-    int ret;
+    Error *err = NULL;
 
     g_strlcpy(combined_key, key, WS_CLIENT_KEY_LEN + 1);
     g_strlcat(combined_key, WS_GUID, WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1);
 
     /* hash and encode it */
-    in.data = (void *)combined_key;
-    in.size = WS_CLIENT_KEY_LEN + WS_GUID_LEN;
-    ret = gnutls_fingerprint(GNUTLS_DIG_SHA1, &in, hash, &hash_size);
-    if (ret == GNUTLS_E_SUCCESS && hash_size <= SHA1_DIGEST_LEN) {
-        accept = g_base64_encode(hash, hash_size);
-    }
-    if (accept == NULL) {
-        VNC_DEBUG("Hashing Websocket combined key failed\n");
+    if (qcrypto_hash_base64(QCRYPTO_HASH_ALG_SHA1,
+                            combined_key,
+                            WS_CLIENT_KEY_LEN + WS_GUID_LEN,
+                            &accept,
+                            &err) < 0) {
+        VNC_DEBUG("Hashing Websocket combined key failed %s\n",
+                  error_get_pretty(err));
+        error_free(err);
         vnc_client_error(vs);
         return;
     }
diff --git a/ui/vnc-ws.h b/ui/vnc-ws.h
index 14d4230..9494225 100644
--- a/ui/vnc-ws.h
+++ b/ui/vnc-ws.h
@@ -21,8 +21,6 @@
 #ifndef __QEMU_UI_VNC_WS_H
 #define __QEMU_UI_VNC_WS_H
 
-#include <gnutls/gnutls.h>
-
 #define B64LEN(__x) (((__x + 2) / 3) * 12 / 3)
 #define SHA1_DIGEST_LEN 20
 
diff --git a/ui/vnc.c b/ui/vnc.c
index 39402d3..ef0d87d 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -38,6 +38,7 @@
 #include "qemu/osdep.h"
 #include "ui/input.h"
 #include "qapi-event.h"
+#include "crypto/hash.h"
 
 #define VNC_REFRESH_INTERVAL_BASE GUI_REFRESH_INTERVAL_DEFAULT
 #define VNC_REFRESH_INTERVAL_INC  50
@@ -353,9 +354,7 @@ static VncClientInfo *qmp_query_vnc_client(const VncState *client)
     info->base->host = g_strdup(host);
     info->base->service = g_strdup(serv);
     info->base->family = inet_netfamily(sa.ss_family);
-#ifdef CONFIG_VNC_WS
     info->base->websocket = client->websocket;
-#endif
 
 #ifdef CONFIG_VNC_TLS
     if (client->tls.session && client->tls.dname) {
@@ -580,12 +579,10 @@ VncInfo2List *qmp_query_vnc_servers(Error **errp)
             info->server = qmp_query_server_entry(vd->lsock, false,
                                                   info->server);
         }
-#ifdef CONFIG_VNC_WS
         if (vd->lwebsock != -1) {
             info->server = qmp_query_server_entry(vd->lwebsock, true,
                                                   info->server);
         }
-#endif
 
         item = g_new0(VncInfo2List, 1);
         item->value = info;
@@ -1229,10 +1226,8 @@ void vnc_disconnect_finish(VncState *vs)
 
     buffer_free(&vs->input);
     buffer_free(&vs->output);
-#ifdef CONFIG_VNC_WS
     buffer_free(&vs->ws_input);
     buffer_free(&vs->ws_output);
-#endif /* CONFIG_VNC_WS */
 
     qapi_free_VncClientInfo(vs->info);
 
@@ -1411,12 +1406,9 @@ static void vnc_client_write_locked(void *opaque)
     } else
 #endif /* CONFIG_VNC_SASL */
     {
-#ifdef CONFIG_VNC_WS
         if (vs->encode_ws) {
             vnc_client_write_ws(vs);
-        } else
-#endif /* CONFIG_VNC_WS */
-        {
+        } else {
             vnc_client_write_plain(vs);
         }
     }
@@ -1427,11 +1419,7 @@ void vnc_client_write(void *opaque)
     VncState *vs = opaque;
 
     vnc_lock_output(vs);
-    if (vs->output.offset
-#ifdef CONFIG_VNC_WS
-            || vs->ws_output.offset
-#endif
-            ) {
+    if (vs->output.offset || vs->ws_output.offset) {
         vnc_client_write_locked(opaque);
     } else if (vs->csock != -1) {
         qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);
@@ -1537,7 +1525,6 @@ void vnc_client_read(void *opaque)
         ret = vnc_client_read_sasl(vs);
     else
 #endif /* CONFIG_VNC_SASL */
-#ifdef CONFIG_VNC_WS
         if (vs->encode_ws) {
             ret = vnc_client_read_ws(vs);
             if (ret == -1) {
@@ -1547,10 +1534,8 @@ void vnc_client_read(void *opaque)
                 vnc_client_error(vs);
                 return;
             }
-        } else
-#endif /* CONFIG_VNC_WS */
-        {
-        ret = vnc_client_read_plain(vs);
+        } else {
+            ret = vnc_client_read_plain(vs);
         }
     if (!ret) {
         if (vs->csock == -1)
@@ -1622,11 +1607,8 @@ void vnc_write_u8(VncState *vs, uint8_t value)
 void vnc_flush(VncState *vs)
 {
     vnc_lock_output(vs);
-    if (vs->csock != -1 && (vs->output.offset
-#ifdef CONFIG_VNC_WS
-                || vs->ws_output.offset
-#endif
-                )) {
+    if (vs->csock != -1 && (vs->output.offset ||
+                            vs->ws_output.offset)) {
         vnc_client_write_locked(vs);
     }
     vnc_unlock_output(vs);
@@ -3017,7 +2999,6 @@ static void vnc_connect(VncDisplay *vd, int csock,
     VNC_DEBUG("New client on socket %d\n", csock);
     update_displaychangelistener(&vd->dcl, VNC_REFRESH_INTERVAL_BASE);
     qemu_set_nonblock(vs->csock);
-#ifdef CONFIG_VNC_WS
     if (websocket) {
         vs->websocket = 1;
 #ifdef CONFIG_VNC_TLS
@@ -3030,9 +3011,7 @@ static void vnc_connect(VncDisplay *vd, int csock,
             qemu_set_fd_handler2(vs->csock, NULL, vncws_handshake_read,
                                  NULL, vs);
         }
-    } else
-#endif /* CONFIG_VNC_WS */
-    {
+    } else {
         qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);
     }
 
@@ -3040,10 +3019,7 @@ static void vnc_connect(VncDisplay *vd, int csock,
     vnc_qmp_event(vs, QAPI_EVENT_VNC_CONNECTED);
     vnc_set_share_mode(vs, VNC_SHARE_MODE_CONNECTING);
 
-#ifdef CONFIG_VNC_WS
-    if (!vs->websocket)
-#endif
-    {
+    if (!vs->websocket) {
         vnc_init_state(vs);
     }
 
@@ -3099,12 +3075,9 @@ static void vnc_listen_read(void *opaque, bool websocket)
 
     /* Catch-up */
     graphic_hw_update(vs->dcl.con);
-#ifdef CONFIG_VNC_WS
     if (websocket) {
         csock = qemu_accept(vs->lwebsock, (struct sockaddr *)&addr, &addrlen);
-    } else
-#endif /* CONFIG_VNC_WS */
-    {
+    } else {
         csock = qemu_accept(vs->lsock, (struct sockaddr *)&addr, &addrlen);
     }
 
@@ -3119,12 +3092,10 @@ static void vnc_listen_regular_read(void *opaque)
     vnc_listen_read(opaque, false);
 }
 
-#ifdef CONFIG_VNC_WS
 static void vnc_listen_websocket_read(void *opaque)
 {
     vnc_listen_read(opaque, true);
 }
-#endif /* CONFIG_VNC_WS */
 
 static const DisplayChangeListenerOps dcl_ops = {
     .dpy_name             = "vnc",
@@ -3150,9 +3121,7 @@ void vnc_display_init(const char *id)
     QTAILQ_INSERT_TAIL(&vnc_displays, vs, next);
 
     vs->lsock = -1;
-#ifdef CONFIG_VNC_WS
     vs->lwebsock = -1;
-#endif
 
     QTAILQ_INIT(&vs->clients);
     vs->expires = TIME_MAX;
@@ -3186,14 +3155,12 @@ static void vnc_display_close(VncDisplay *vs)
         close(vs->lsock);
         vs->lsock = -1;
     }
-#ifdef CONFIG_VNC_WS
     vs->ws_enabled = false;
     if (vs->lwebsock != -1) {
         qemu_set_fd_handler2(vs->lwebsock, NULL, NULL, NULL, NULL);
         close(vs->lwebsock);
         vs->lwebsock = -1;
     }
-#endif /* CONFIG_VNC_WS */
     vs->auth = VNC_AUTH_INVALID;
     vs->subauth = VNC_AUTH_INVALID;
 #ifdef CONFIG_VNC_TLS
@@ -3572,13 +3539,12 @@ void vnc_display_open(const char *id, Error **errp)
 
     websocket = qemu_opt_get(opts, "websocket");
     if (websocket) {
-#ifdef CONFIG_VNC_WS
         vs->ws_enabled = true;
         qemu_opt_set(wsopts, "port", websocket, &error_abort);
-#else /* ! CONFIG_VNC_WS */
-        error_setg(errp, "Websockets protocol requires gnutls support");
-        goto fail;
-#endif /* ! CONFIG_VNC_WS */
+        if (!qcrypto_hash_supports(QCRYPTO_HASH_ALG_SHA1)) {
+            error_setg(errp, "SHA1 hash support is required for websockets");
+            goto fail;
+        }
     }
 
 #ifdef CONFIG_VNC_JPEG
@@ -3661,9 +3627,7 @@ void vnc_display_open(const char *id, Error **errp)
         /* connect to viewer */
         int csock;
         vs->lsock = -1;
-#ifdef CONFIG_VNC_WS
         vs->lwebsock = -1;
-#endif
         if (strncmp(vnc, "unix:", 5) == 0) {
             csock = unix_connect(vnc+5, errp);
         } else {
@@ -3683,7 +3647,6 @@ void vnc_display_open(const char *id, Error **errp)
             if (vs->lsock < 0) {
                 goto fail;
             }
-#ifdef CONFIG_VNC_WS
             if (vs->ws_enabled) {
                 vs->lwebsock = inet_listen_opts(wsopts, 0, errp);
                 if (vs->lwebsock < 0) {
@@ -3694,17 +3657,14 @@ void vnc_display_open(const char *id, Error **errp)
                     goto fail;
                 }
             }
-#endif /* CONFIG_VNC_WS */
         }
         vs->enabled = true;
         qemu_set_fd_handler2(vs->lsock, NULL,
                 vnc_listen_regular_read, NULL, vs);
-#ifdef CONFIG_VNC_WS
         if (vs->ws_enabled) {
             qemu_set_fd_handler2(vs->lwebsock, NULL,
                     vnc_listen_websocket_read, NULL, vs);
         }
-#endif /* CONFIG_VNC_WS */
     }
     qemu_opts_del(sopts);
     qemu_opts_del(wsopts);
@@ -3714,9 +3674,7 @@ fail:
     qemu_opts_del(sopts);
     qemu_opts_del(wsopts);
     vs->enabled = false;
-#ifdef CONFIG_VNC_WS
     vs->ws_enabled = false;
-#endif /* CONFIG_VNC_WS */
 }
 
 void vnc_display_add_client(const char *id, int csock, bool skipauth)
diff --git a/ui/vnc.h b/ui/vnc.h
index 3f7c6a9..814d720 100644
--- a/ui/vnc.h
+++ b/ui/vnc.h
@@ -108,9 +108,7 @@ typedef struct VncDisplay VncDisplay;
 #ifdef CONFIG_VNC_SASL
 #include "vnc-auth-sasl.h"
 #endif
-#ifdef CONFIG_VNC_WS
 #include "vnc-ws.h"
-#endif
 
 struct VncRectStat
 {
@@ -156,10 +154,8 @@ struct VncDisplay
     int connections_limit;
     VncSharePolicy share_policy;
     int lsock;
-#ifdef CONFIG_VNC_WS
     int lwebsock;
     bool ws_enabled;
-#endif
     DisplaySurface *ds;
     DisplayChangeListener dcl;
     kbd_layout_t *kbd_layout;
@@ -294,21 +290,17 @@ struct VncState
 #ifdef CONFIG_VNC_SASL
     VncStateSASL sasl;
 #endif
-#ifdef CONFIG_VNC_WS
     bool encode_ws;
     bool websocket;
-#endif /* CONFIG_VNC_WS */
 
     VncClientInfo *info;
 
     Buffer output;
     Buffer input;
-#ifdef CONFIG_VNC_WS
     Buffer ws_input;
     Buffer ws_output;
     size_t ws_payload_remain;
     WsMask ws_payload_mask;
-#endif
     /* current output mode information */
     VncWritePixels *write_pixels;
     PixelFormat client_pf;
-- 
2.1.0