The `nixos-rebuild` tool calls `get-version-suffix` to figure out the
git revision of the nixpkgs directory if there is a .git.
https://nvd.nist.gov/vuln/detail/CVE-2022-24765 made git throw an
error if the .git search logic is not turned off and a user
tries to access a `.git` directory they don’t own (otherwise a
different user could trick them into setting arbitrary git config).
So from now on we should always explicitely set `--git-dir`, which
turns this search logic (and thus the security check) off.
This reverts commit 1e534e234b.
We already should have a .git directory if it is managed via Git,
otherwise there is no way to get the Git revision if neither
.git-revision or .git is present.
But having .git-revision _and_ .git present seems very much redundant to
me.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Cc: @bennofs, @Profpatsch
Issue: #17218
