mesa: check for bufSize > 0 in _mesa_GetSynciv()

The spec doesn't say GL_INVALID_VALUE should be raised for bufSize <= 0.
In any case, memcpy(len < 0) will lead to a crash, so don't allow it.

CC: "9.2" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
1 file changed