[Spice-devel] [PATCH spice-server v2 1/2] stream-device: handle cursor from device
Frediano Ziglio
fziglio at redhat.com
Fri Feb 9 09:10:48 UTC 2018
Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
---
server/stream-device.c | 169 +++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 162 insertions(+), 7 deletions(-)
Changes since v1:
- add some comments with some implementation explanation;
- better computation of max cursor size.
diff --git a/server/stream-device.c b/server/stream-device.c
index 735f2933..a5606d6a 100644
--- a/server/stream-device.c
+++ b/server/stream-device.c
@@ -23,6 +23,7 @@
#include "char-device.h"
#include "stream-channel.h"
+#include "cursor-channel.h"
#include "reds.h"
#define TYPE_STREAM_DEVICE stream_device_get_type()
@@ -45,13 +46,16 @@ struct StreamDevice {
union {
StreamMsgFormat format;
StreamMsgCapabilities capabilities;
+ StreamMsgCursorSet cursor_set;
uint8_t buf[STREAM_MSG_CAPABILITIES_MAX_BYTES];
- } msg;
+ } *msg;
uint32_t msg_pos;
+ uint32_t msg_len;
bool has_error;
bool opened;
bool flow_stopped;
StreamChannel *stream_channel;
+ CursorChannel *cursor_channel;
};
struct StreamDeviceClass {
@@ -66,7 +70,7 @@ G_DEFINE_TYPE(StreamDevice, stream_device, RED_TYPE_CHAR_DEVICE)
typedef bool StreamMsgHandler(StreamDevice *dev, SpiceCharDeviceInstance *sin)
SPICE_GNUC_WARN_UNUSED_RESULT;
-static StreamMsgHandler handle_msg_format, handle_msg_data;
+static StreamMsgHandler handle_msg_format, handle_msg_data, handle_msg_cursor_set;
static bool handle_msg_invalid(StreamDevice *dev, SpiceCharDeviceInstance *sin,
const char *error_msg) SPICE_GNUC_WARN_UNUSED_RESULT;
@@ -108,6 +112,16 @@ stream_device_read_msg_from_dev(RedCharDevice *self, SpiceCharDeviceInstance *si
dev->hdr.type = GUINT16_FROM_LE(dev->hdr.type);
dev->hdr.size = GUINT32_FROM_LE(dev->hdr.size);
dev->msg_pos = 0;
+ // reallocate to the minimum.
+ // Currently the only message that requires resizing is
+ // the cursor shape which is not expected to be sent so
+ // often.
+ // Avoid to use dev->hdr.size as this allows easily DoS
+ // against the server.
+ if (dev->msg_len > sizeof(*dev->msg)) {
+ dev->msg = g_realloc(dev->msg, sizeof(*dev->msg));
+ dev->msg_len = sizeof(*dev->msg);
+ }
}
}
@@ -122,6 +136,9 @@ stream_device_read_msg_from_dev(RedCharDevice *self, SpiceCharDeviceInstance *si
case STREAM_TYPE_DATA:
handled = handle_msg_data(dev, sin);
break;
+ case STREAM_TYPE_CURSOR_SET:
+ handled = handle_msg_cursor_set(dev, sin);
+ break;
case STREAM_TYPE_CAPABILITIES:
/* FIXME */
default:
@@ -194,7 +211,7 @@ handle_msg_format(StreamDevice *dev, SpiceCharDeviceInstance *sin)
spice_assert(dev->hdr.type == STREAM_TYPE_FORMAT);
}
- int n = sif->read(sin, dev->msg.buf + dev->msg_pos, sizeof(StreamMsgFormat) - dev->msg_pos);
+ int n = sif->read(sin, dev->msg->buf + dev->msg_pos, sizeof(StreamMsgFormat) - dev->msg_pos);
if (n < 0) {
return handle_msg_invalid(dev, sin, NULL);
}
@@ -205,9 +222,9 @@ handle_msg_format(StreamDevice *dev, SpiceCharDeviceInstance *sin)
return false;
}
- dev->msg.format.width = GUINT32_FROM_LE(dev->msg.format.width);
- dev->msg.format.height = GUINT32_FROM_LE(dev->msg.format.height);
- stream_channel_change_format(dev->stream_channel, &dev->msg.format);
+ dev->msg->format.width = GUINT32_FROM_LE(dev->msg->format.width);
+ dev->msg->format.height = GUINT32_FROM_LE(dev->msg->format.height);
+ stream_channel_change_format(dev->stream_channel, &dev->msg->format);
return true;
}
@@ -238,6 +255,116 @@ handle_msg_data(StreamDevice *dev, SpiceCharDeviceInstance *sin)
return dev->hdr.size == 0;
}
+/*
+ * Returns number of bits required for a pixel of a given cursor type.
+ *
+ * Take into account mask bits.
+ * Returns 0 on error.
+ */
+static unsigned int
+get_cursor_type_bits(unsigned int cursor_type)
+{
+ switch (cursor_type) {
+ case SPICE_CURSOR_TYPE_ALPHA:
+ // RGBA
+ return 32;
+ case SPICE_CURSOR_TYPE_COLOR24:
+ // RGB + bitmask
+ return 24 + 1;
+ case SPICE_CURSOR_TYPE_COLOR32:
+ // RGBx + bitmask
+ return 32 + 1;
+ default:
+ return 0;
+ }
+}
+
+static RedCursorCmd *
+stream_msg_cursor_set_to_cursor_cmd(const StreamMsgCursorSet *msg, size_t msg_size)
+{
+ RedCursorCmd *cmd = g_new0(RedCursorCmd, 1);
+ cmd->type = QXL_CURSOR_SET;
+ cmd->u.set.position.x = 0; // TODO
+ cmd->u.set.position.y = 0; // TODO
+ cmd->u.set.visible = 1; // TODO
+ SpiceCursor *cursor = &cmd->u.set.shape;
+ cursor->header.unique = 0;
+ cursor->header.type = msg->type;
+ cursor->header.width = GUINT16_FROM_LE(msg->width);
+ cursor->header.height = GUINT16_FROM_LE(msg->height);
+ cursor->header.hot_spot_x = GUINT16_FROM_LE(msg->hot_spot_x);
+ cursor->header.hot_spot_y = GUINT16_FROM_LE(msg->hot_spot_y);
+
+ /* Limit cursor size to prevent DoS */
+ if (cursor->header.width > STREAM_MSG_CURSOR_SET_MAX_WIDTH ||
+ cursor->header.height > STREAM_MSG_CURSOR_SET_MAX_HEIGHT) {
+ g_free(cmd);
+ return NULL;
+ }
+
+ const unsigned int cursor_bits = get_cursor_type_bits(cursor->header.type);
+ if (cursor_bits == 0) {
+ g_free(cmd);
+ return NULL;
+ }
+
+ /* Check that enough data has been sent for the cursor.
+ * Note that these computations can't overflow due to sizes checks
+ * above. */
+ size_t size_required = cursor->header.width * cursor->header.height;
+ size_required = SPICE_ALIGN(size_required * cursor_bits, 8) / 8u;
+ if (msg_size < sizeof(StreamMsgCursorSet) + size_required) {
+ g_free(cmd);
+ return NULL;
+ }
+ cursor->data_size = size_required;
+ cursor->data = spice_memdup(msg->data, size_required);
+ return cmd;
+}
+
+static bool
+handle_msg_cursor_set(StreamDevice *dev, SpiceCharDeviceInstance *sin)
+{
+ // maximum size taking into account 32 bit image with bitmask
+ const unsigned int max_cursor_set_size =
+ (STREAM_MSG_CURSOR_SET_MAX_WIDTH * 4 + (STREAM_MSG_CURSOR_SET_MAX_WIDTH + 7)/8)
+ * STREAM_MSG_CURSOR_SET_MAX_HEIGHT;
+
+ SpiceCharDeviceInterface *sif = spice_char_device_get_interface(sin);
+
+ if (dev->hdr.size < sizeof(StreamMsgCursorSet)) {
+ return handle_msg_invalid(dev, sin, NULL);
+ }
+ if (dev->hdr.size > max_cursor_set_size) {
+ // we could skip the message but on the other end the client
+ // is buggy in any case
+ return handle_msg_invalid(dev, sin, "Cursor sent is too big");
+ }
+
+ // read part of the message till we get all
+ if (dev->msg_len < dev->hdr.size) {
+ dev->msg = g_realloc(dev->msg, dev->hdr.size);
+ dev->msg_len = dev->hdr.size;
+ }
+ int n = sif->read(sin, dev->msg->buf + dev->msg_pos, dev->hdr.size - dev->msg_pos);
+ if (n <= 0) {
+ return false;
+ }
+ dev->msg_pos += n;
+ if (dev->msg_pos != dev->hdr.size) {
+ return false;
+ }
+
+ // transform the message to a cursor command and process it
+ RedCursorCmd *cmd = stream_msg_cursor_set_to_cursor_cmd(&dev->msg->cursor_set, dev->msg_pos);
+ if (!cmd) {
+ return handle_msg_invalid(dev, sin, NULL);
+ }
+ cursor_channel_process_cmd(dev->cursor_channel, cmd);
+
+ return true;
+}
+
static void
stream_device_send_msg_to_client(RedCharDevice *self, RedPipeItem *msg, RedClient *client)
{
@@ -335,6 +462,22 @@ stream_device_dispose(GObject *object)
red_channel_destroy(RED_CHANNEL(dev->stream_channel));
dev->stream_channel = NULL;
}
+ if (dev->cursor_channel) {
+ // close all current connections and drop the reference
+ red_channel_destroy(RED_CHANNEL(dev->cursor_channel));
+ dev->cursor_channel = NULL;
+ }
+}
+
+static void
+stream_device_finalize(GObject *object)
+{
+ StreamDevice *dev = STREAM_DEVICE(object);
+
+ g_free(dev->msg);
+ dev->msg = NULL;
+ dev->msg_len = 0;
+ dev->msg_pos = 0;
}
static void
@@ -345,13 +488,22 @@ allocate_channels(StreamDevice *dev)
}
SpiceServer* reds = red_char_device_get_server(RED_CHAR_DEVICE(dev));
+ SpiceCoreInterfaceInternal* core = reds_get_core_interface(reds);
int id = reds_get_free_channel_id(reds, SPICE_CHANNEL_DISPLAY);
g_return_if_fail(id >= 0);
StreamChannel *stream_channel = stream_channel_new(reds, id);
+ CursorChannel *cursor_channel = cursor_channel_new(reds, id, core);
+ ClientCbs client_cbs = { NULL, };
+ client_cbs.connect = (channel_client_connect_proc) cursor_channel_connect;
+ client_cbs.migrate = cursor_channel_client_migrate;
+ red_channel_register_client_cbs(RED_CHANNEL(cursor_channel), &client_cbs, NULL);
+ reds_register_channel(reds, RED_CHANNEL(cursor_channel));
+
dev->stream_channel = stream_channel;
+ dev->cursor_channel = cursor_channel;
stream_channel_register_start_cb(stream_channel, stream_device_stream_start, dev);
stream_channel_register_queue_stat_cb(stream_channel, stream_device_stream_queue_stat, dev);
@@ -413,6 +565,7 @@ stream_device_class_init(StreamDeviceClass *klass)
RedCharDeviceClass *char_dev_class = RED_CHAR_DEVICE_CLASS(klass);
object_class->dispose = stream_device_dispose;
+ object_class->finalize = stream_device_finalize;
char_dev_class->read_one_msg_from_device = stream_device_read_msg_from_dev;
char_dev_class->send_msg_to_client = stream_device_send_msg_to_client;
@@ -422,8 +575,10 @@ stream_device_class_init(StreamDeviceClass *klass)
}
static void
-stream_device_init(StreamDevice *self)
+stream_device_init(StreamDevice *dev)
{
+ dev->msg = g_malloc(sizeof(*dev->msg));
+ dev->msg_len = sizeof(*dev->msg);
}
static StreamDevice *
--
2.14.3
More information about the Spice-devel
mailing list