diff options
author | Gerd Hoffmann <kraxel@redhat.com> | 2014-10-02 12:09:34 +0200 |
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committer | Gerd Hoffmann <kraxel@redhat.com> | 2015-01-22 11:18:47 +0100 |
commit | e5f34cdd2da54f28d90889a3afd15fad2d6105ff (patch) | |
tree | b4bb4eafa06d5c95b7d8413f49e1d18bd4ab4185 /ui/vnc.c | |
parent | 86fdcf23f4a9d8473844734907555b3a93ed686c (diff) | |
download | hqemu-e5f34cdd2da54f28d90889a3afd15fad2d6105ff.zip hqemu-e5f34cdd2da54f28d90889a3afd15fad2d6105ff.tar.gz |
vnc: track & limit connections
Also track the number of connections in "connecting" and "shared" state
(in addition to the "exclusive" state). Apply a configurable limit to
these connections.
The logic to apply the limit to connections in "shared" state is pretty
simple: When the limit is reached no new connections are allowed.
The logic to apply the limit to connections in "connecting" state (this
is the state you are in *before* successful authentication) is
slightly different: A new connect kicks out the oldest client which is
still in "connecting" state. This avoids a easy DoS by unauthenticated
users by simply opening connections until the limit is reached.
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Diffstat (limited to 'ui/vnc.c')
-rw-r--r-- | ui/vnc.c | 46 |
1 files changed, 43 insertions, 3 deletions
@@ -68,12 +68,34 @@ static void vnc_set_share_mode(VncState *vs, VncShareMode mode) vs->csock, mn[vs->share_mode], mn[mode]); #endif - if (vs->share_mode == VNC_SHARE_MODE_EXCLUSIVE) { + switch (vs->share_mode) { + case VNC_SHARE_MODE_CONNECTING: + vs->vd->num_connecting--; + break; + case VNC_SHARE_MODE_SHARED: + vs->vd->num_shared--; + break; + case VNC_SHARE_MODE_EXCLUSIVE: vs->vd->num_exclusive--; + break; + default: + break; } + vs->share_mode = mode; - if (vs->share_mode == VNC_SHARE_MODE_EXCLUSIVE) { + + switch (vs->share_mode) { + case VNC_SHARE_MODE_CONNECTING: + vs->vd->num_connecting++; + break; + case VNC_SHARE_MODE_SHARED: + vs->vd->num_shared++; + break; + case VNC_SHARE_MODE_EXCLUSIVE: vs->vd->num_exclusive++; + break; + default: + break; } } @@ -2337,6 +2359,11 @@ static int protocol_client_init(VncState *vs, uint8_t *data, size_t len) } vnc_set_share_mode(vs, mode); + if (vs->vd->num_shared > vs->vd->connections_limit) { + vnc_disconnect_start(vs); + return 0; + } + vs->client_width = pixman_image_get_width(vs->vd->server); vs->client_height = pixman_image_get_height(vs->vd->server); vnc_write_u16(vs, vs->client_width); @@ -2889,6 +2916,15 @@ static void vnc_connect(VncDisplay *vd, int csock, { vnc_init_state(vs); } + + if (vd->num_connecting > vd->connections_limit) { + QTAILQ_FOREACH(vs, &vd->clients, next) { + if (vs->share_mode == VNC_SHARE_MODE_CONNECTING) { + vnc_disconnect_start(vs); + return; + } + } + } } void vnc_init_state(VncState *vs) @@ -2907,7 +2943,7 @@ void vnc_init_state(VncState *vs) qemu_mutex_init(&vs->output_mutex); vs->bh = qemu_bh_new(vnc_jobs_bh, vs); - QTAILQ_INSERT_HEAD(&vd->clients, vs, next); + QTAILQ_INSERT_TAIL(&vd->clients, vs, next); graphic_hw_update(vd->dcl.con); @@ -3098,6 +3134,9 @@ static QemuOptsList qemu_vnc_opts = { .name = "head", .type = QEMU_OPT_NUMBER, },{ + .name = "connections", + .type = QEMU_OPT_NUMBER, + },{ .name = "password", .type = QEMU_OPT_BOOL, },{ @@ -3211,6 +3250,7 @@ void vnc_display_open(const char *id, Error **errp) } else { vs->share_policy = VNC_SHARE_POLICY_ALLOW_EXCLUSIVE; } + vs->connections_limit = qemu_opt_get_number(opts, "connections", 32); #ifdef CONFIG_VNC_WS websocket = qemu_opt_get(opts, "websocket"); |