much too small I think
SA-11/16 'Buk' / 'Shtil' missile is about 5.5m long and has a wingspan of just over 1m. However, the VLS version the Russians were showing off (in model form only?) had a much reduced wingspan and was associated with very compact square launch containers.
Ok, looking at the truck we can start to estimate the size of the container. The easy bit is the diameter because it is just under a third of the width of the truck. I'm not exactly sure of the model of truck but most PLA trucks in the 6-8 tons range are about 2.5m wide. So the diameter of the tube is about 0.75-0.8m. That's actually signifigantly bigger than HQ-7 @ 0.6m.*
Length is harder. Trucks that size vary in length greatly in part due to cab configurations. But the flat bed section is likely to be about 6-7m long.
Um, ok, it could be a Shtil derived missile, can't rule that out from the size of the container. Surprised it doesn't look like the VLS Shtil Russia takes to trade shows though.
* another comparison is that an HQ-7 naval mount, which is three tubes wide, fits onto the back of a truck this size quite neatly and that has a chunky support either side of the tubes.