Aluminum profiles in various shapes are available at well-stocked hardware stores. Maybe not exactly that one, but you can probably figure out something similar with what's available, I believe.
For example, you could use this one:
https://www.byggmax.se/u-profil-aluminium-silver-20x18x20x131m-p208171
Mount it like a C, with the "roof" against the ceiling. Drill holes for screws in the "roof" and corresponding larger holes in the "floor" so that the screw head goes through and you have space to screw.
For example, you could use this one:
https://www.byggmax.se/u-profil-aluminium-silver-20x18x20x131m-p208171
Mount it like a C, with the "roof" against the ceiling. Drill holes for screws in the "roof" and corresponding larger holes in the "floor" so that the screw head goes through and you have space to screw.