nix-build foo.nix: cannot create directory under /nix/store

[sbellem]

Question to ask at https://discourse.nixos.org/. Reached the current limit for today. Ask tomorrow.

When trying to build a derivation, say foo.nix, with nix-build foo.nix I get the following error:

mkdir: cannot create directory '/nix/store/.../_build': Permission denied

The builder of the derivation is custom, and is like so:

# builder.sh
source $stdenv/setup

make sometarget
# ...