338 lines
11 KiB
Perl
338 lines
11 KiB
Perl
use strict;
|
||
use File::Path qw(make_path);
|
||
use File::Slurp;
|
||
use JSON;
|
||
|
||
make_path("/var/lib/nixos", { mode => 0755 });
|
||
|
||
|
||
# Keep track of deleted uids and gids.
|
||
my $uidMapFile = "/var/lib/nixos/uid-map";
|
||
my $uidMap = -e $uidMapFile ? decode_json(read_file($uidMapFile)) : {};
|
||
|
||
my $gidMapFile = "/var/lib/nixos/gid-map";
|
||
my $gidMap = -e $gidMapFile ? decode_json(read_file($gidMapFile)) : {};
|
||
|
||
|
||
sub updateFile {
|
||
my ($path, $contents, $perms) = @_;
|
||
write_file("$path.tmp", { binmode => ':utf8', perms => $perms // 0644 }, $contents);
|
||
rename("$path.tmp", $path) or die;
|
||
}
|
||
|
||
|
||
sub hashPassword {
|
||
my ($password) = @_;
|
||
my $salt = "";
|
||
my @chars = ('.', '/', 0..9, 'A'..'Z', 'a'..'z');
|
||
$salt .= $chars[rand 64] for (1..8);
|
||
return crypt($password, '$6$' . $salt . '$');
|
||
}
|
||
|
||
|
||
# Functions for allocating free GIDs/UIDs. FIXME: respect ID ranges in
|
||
# /etc/login.defs.
|
||
sub allocId {
|
||
my ($used, $prevUsed, $idMin, $idMax, $up, $getid) = @_;
|
||
my $id = $up ? $idMin : $idMax;
|
||
while ($id >= $idMin && $id <= $idMax) {
|
||
if (!$used->{$id} && !$prevUsed->{$id} && !defined &$getid($id)) {
|
||
$used->{$id} = 1;
|
||
return $id;
|
||
}
|
||
$used->{$id} = 1;
|
||
if ($up) { $id++; } else { $id--; }
|
||
}
|
||
die "$0: out of free UIDs or GIDs\n";
|
||
}
|
||
|
||
my (%gidsUsed, %uidsUsed, %gidsPrevUsed, %uidsPrevUsed);
|
||
|
||
sub allocGid {
|
||
my ($name) = @_;
|
||
my $prevGid = $gidMap->{$name};
|
||
if (defined $prevGid && !defined $gidsUsed{$prevGid}) {
|
||
print STDERR "reviving group '$name' with GID $prevGid\n";
|
||
$gidsUsed{$prevGid} = 1;
|
||
return $prevGid;
|
||
}
|
||
return allocId(\%gidsUsed, \%gidsPrevUsed, 400, 999, 0, sub { my ($gid) = @_; getgrgid($gid) });
|
||
}
|
||
|
||
sub allocUid {
|
||
my ($name, $isSystemUser) = @_;
|
||
my ($min, $max, $up) = $isSystemUser ? (400, 999, 0) : (1000, 29999, 1);
|
||
my $prevUid = $uidMap->{$name};
|
||
if (defined $prevUid && $prevUid >= $min && $prevUid <= $max && !defined $uidsUsed{$prevUid}) {
|
||
print STDERR "reviving user '$name' with UID $prevUid\n";
|
||
$uidsUsed{$prevUid} = 1;
|
||
return $prevUid;
|
||
}
|
||
return allocId(\%uidsUsed, \%uidsPrevUsed, $min, $max, $up, sub { my ($uid) = @_; getpwuid($uid) });
|
||
}
|
||
|
||
|
||
# Read the declared users/groups.
|
||
my $spec = decode_json(read_file($ARGV[0]));
|
||
|
||
# Don't allocate UIDs/GIDs that are manually assigned.
|
||
foreach my $g (@{$spec->{groups}}) {
|
||
$gidsUsed{$g->{gid}} = 1 if defined $g->{gid};
|
||
}
|
||
|
||
foreach my $u (@{$spec->{users}}) {
|
||
$uidsUsed{$u->{uid}} = 1 if defined $u->{uid};
|
||
}
|
||
|
||
# Likewise for previously used but deleted UIDs/GIDs.
|
||
$uidsPrevUsed{$_} = 1 foreach values %{$uidMap};
|
||
$gidsPrevUsed{$_} = 1 foreach values %{$gidMap};
|
||
|
||
|
||
# Read the current /etc/group.
|
||
sub parseGroup {
|
||
chomp;
|
||
my @f = split(':', $_, -4);
|
||
my $gid = $f[2] eq "" ? undef : int($f[2]);
|
||
$gidsUsed{$gid} = 1 if defined $gid;
|
||
return ($f[0], { name => $f[0], password => $f[1], gid => $gid, members => $f[3] });
|
||
}
|
||
|
||
my %groupsCur = -f "/etc/group" ? map { parseGroup } read_file("/etc/group") : ();
|
||
|
||
# Read the current /etc/passwd.
|
||
sub parseUser {
|
||
chomp;
|
||
my @f = split(':', $_, -7);
|
||
my $uid = $f[2] eq "" ? undef : int($f[2]);
|
||
$uidsUsed{$uid} = 1 if defined $uid;
|
||
return ($f[0], { name => $f[0], fakePassword => $f[1], uid => $uid,
|
||
gid => $f[3], description => $f[4], home => $f[5], shell => $f[6] });
|
||
}
|
||
|
||
my %usersCur = -f "/etc/passwd" ? map { parseUser } read_file("/etc/passwd") : ();
|
||
|
||
# Read the groups that were created declaratively (i.e. not by groups)
|
||
# in the past. These must be removed if they are no longer in the
|
||
# current spec.
|
||
my $declGroupsFile = "/var/lib/nixos/declarative-groups";
|
||
my %declGroups;
|
||
$declGroups{$_} = 1 foreach split / /, -e $declGroupsFile ? read_file($declGroupsFile) : "";
|
||
|
||
# Idem for the users.
|
||
my $declUsersFile = "/var/lib/nixos/declarative-users";
|
||
my %declUsers;
|
||
$declUsers{$_} = 1 foreach split / /, -e $declUsersFile ? read_file($declUsersFile) : "";
|
||
|
||
|
||
# Generate a new /etc/group containing the declared groups.
|
||
my %groupsOut;
|
||
foreach my $g (@{$spec->{groups}}) {
|
||
my $name = $g->{name};
|
||
my $existing = $groupsCur{$name};
|
||
|
||
my %members = map { ($_, 1) } @{$g->{members}};
|
||
|
||
if (defined $existing) {
|
||
$g->{gid} = $existing->{gid} if !defined $g->{gid};
|
||
if ($g->{gid} != $existing->{gid}) {
|
||
warn "warning: not applying GID change of group ‘$name’ ($existing->{gid} -> $g->{gid})\n";
|
||
$g->{gid} = $existing->{gid};
|
||
}
|
||
$g->{password} = $existing->{password}; # do we want this?
|
||
if ($spec->{mutableUsers}) {
|
||
# Merge in non-declarative group members.
|
||
foreach my $uname (split /,/, $existing->{members} // "") {
|
||
$members{$uname} = 1 if !defined $declUsers{$uname};
|
||
}
|
||
}
|
||
} else {
|
||
$g->{gid} = allocGid($name) if !defined $g->{gid};
|
||
$g->{password} = "x";
|
||
}
|
||
|
||
$g->{members} = join ",", sort(keys(%members));
|
||
$groupsOut{$name} = $g;
|
||
|
||
$gidMap->{$name} = $g->{gid};
|
||
}
|
||
|
||
# Update the persistent list of declarative groups.
|
||
updateFile($declGroupsFile, join(" ", sort(keys %groupsOut)));
|
||
|
||
# Merge in the existing /etc/group.
|
||
foreach my $name (keys %groupsCur) {
|
||
my $g = $groupsCur{$name};
|
||
next if defined $groupsOut{$name};
|
||
if (!$spec->{mutableUsers} || defined $declGroups{$name}) {
|
||
print STDERR "removing group ‘$name’\n";
|
||
} else {
|
||
$groupsOut{$name} = $g;
|
||
}
|
||
}
|
||
|
||
|
||
# Rewrite /etc/group. FIXME: acquire lock.
|
||
my @lines = map { join(":", $_->{name}, $_->{password}, $_->{gid}, $_->{members}) . "\n" }
|
||
(sort { $a->{gid} <=> $b->{gid} } values(%groupsOut));
|
||
updateFile($gidMapFile, encode_json($gidMap));
|
||
updateFile("/etc/group", \@lines);
|
||
system("nscd --invalidate group");
|
||
|
||
# Generate a new /etc/passwd containing the declared users.
|
||
my %usersOut;
|
||
foreach my $u (@{$spec->{users}}) {
|
||
my $name = $u->{name};
|
||
|
||
# Resolve the gid of the user.
|
||
if ($u->{group} =~ /^[0-9]$/) {
|
||
$u->{gid} = $u->{group};
|
||
} elsif (defined $groupsOut{$u->{group}}) {
|
||
$u->{gid} = $groupsOut{$u->{group}}->{gid} // die;
|
||
} else {
|
||
warn "warning: user ‘$name’ has unknown group ‘$u->{group}’\n";
|
||
$u->{gid} = 65534;
|
||
}
|
||
|
||
my $existing = $usersCur{$name};
|
||
if (defined $existing) {
|
||
$u->{uid} = $existing->{uid} if !defined $u->{uid};
|
||
if ($u->{uid} != $existing->{uid}) {
|
||
warn "warning: not applying UID change of user ‘$name’ ($existing->{uid} -> $u->{uid})\n";
|
||
$u->{uid} = $existing->{uid};
|
||
}
|
||
} else {
|
||
$u->{uid} = allocUid($name, $u->{isSystemUser}) if !defined $u->{uid};
|
||
|
||
if (defined $u->{initialPassword}) {
|
||
$u->{hashedPassword} = hashPassword($u->{initialPassword});
|
||
} elsif (defined $u->{initialHashedPassword}) {
|
||
$u->{hashedPassword} = $u->{initialHashedPassword};
|
||
}
|
||
}
|
||
|
||
# Create a home directory.
|
||
if ($u->{createHome}) {
|
||
make_path($u->{home}, { mode => 0700 }) if ! -e $u->{home};
|
||
chown $u->{uid}, $u->{gid}, $u->{home};
|
||
}
|
||
|
||
if (defined $u->{passwordFile}) {
|
||
if (-e $u->{passwordFile}) {
|
||
$u->{hashedPassword} = read_file($u->{passwordFile});
|
||
chomp $u->{hashedPassword};
|
||
} else {
|
||
warn "warning: password file ‘$u->{passwordFile}’ does not exist\n";
|
||
}
|
||
} elsif (defined $u->{password}) {
|
||
$u->{hashedPassword} = hashPassword($u->{password});
|
||
}
|
||
|
||
$u->{fakePassword} = $existing->{fakePassword} // "x";
|
||
$usersOut{$name} = $u;
|
||
|
||
$uidMap->{$name} = $u->{uid};
|
||
}
|
||
|
||
# Update the persistent list of declarative users.
|
||
updateFile($declUsersFile, join(" ", sort(keys %usersOut)));
|
||
|
||
# Merge in the existing /etc/passwd.
|
||
foreach my $name (keys %usersCur) {
|
||
my $u = $usersCur{$name};
|
||
next if defined $usersOut{$name};
|
||
if (!$spec->{mutableUsers} || defined $declUsers{$name}) {
|
||
print STDERR "removing user ‘$name’\n";
|
||
} else {
|
||
$usersOut{$name} = $u;
|
||
}
|
||
}
|
||
|
||
# Rewrite /etc/passwd. FIXME: acquire lock.
|
||
@lines = map { join(":", $_->{name}, $_->{fakePassword}, $_->{uid}, $_->{gid}, $_->{description}, $_->{home}, $_->{shell}) . "\n" }
|
||
(sort { $a->{uid} <=> $b->{uid} } (values %usersOut));
|
||
updateFile($uidMapFile, encode_json($uidMap));
|
||
updateFile("/etc/passwd", \@lines);
|
||
system("nscd --invalidate passwd");
|
||
|
||
|
||
# Rewrite /etc/shadow to add new accounts or remove dead ones.
|
||
my @shadowNew;
|
||
my %shadowSeen;
|
||
|
||
foreach my $line (-f "/etc/shadow" ? read_file("/etc/shadow") : ()) {
|
||
chomp $line;
|
||
my ($name, $hashedPassword, @rest) = split(':', $line, -9);
|
||
my $u = $usersOut{$name};;
|
||
next if !defined $u;
|
||
$hashedPassword = "!" if !$spec->{mutableUsers};
|
||
$hashedPassword = $u->{hashedPassword} if defined $u->{hashedPassword} && !$spec->{mutableUsers}; # FIXME
|
||
chomp $hashedPassword;
|
||
push @shadowNew, join(":", $name, $hashedPassword, @rest) . "\n";
|
||
$shadowSeen{$name} = 1;
|
||
}
|
||
|
||
foreach my $u (values %usersOut) {
|
||
next if defined $shadowSeen{$u->{name}};
|
||
my $hashedPassword = "!";
|
||
$hashedPassword = $u->{hashedPassword} if defined $u->{hashedPassword};
|
||
# FIXME: set correct value for sp_lstchg.
|
||
push @shadowNew, join(":", $u->{name}, $hashedPassword, "1::::::") . "\n";
|
||
}
|
||
|
||
updateFile("/etc/shadow", \@shadowNew, 0600);
|
||
|
||
# Rewrite /etc/subuid & /etc/subgid to include default container mappings
|
||
|
||
my $subUidMapFile = "/var/lib/nixos/auto-subuid-map";
|
||
my $subUidMap = -e $subUidMapFile ? decode_json(read_file($subUidMapFile)) : {};
|
||
|
||
my (%subUidsUsed, %subUidsPrevUsed);
|
||
|
||
$subUidsPrevUsed{$_} = 1 foreach values %{$subUidMap};
|
||
|
||
sub allocSubUid {
|
||
my ($name, @rest) = @_;
|
||
|
||
# TODO: No upper bounds?
|
||
my ($min, $max, $up) = (100000, 100000 * 100, 1);
|
||
my $prevId = $subUidMap->{$name};
|
||
if (defined $prevId && !defined $subUidsUsed{$prevId}) {
|
||
$subUidsUsed{$prevId} = 1;
|
||
return $prevId;
|
||
}
|
||
|
||
my $id = allocId(\%subUidsUsed, \%subUidsPrevUsed, $min, $max, $up, sub { my ($uid) = @_; getpwuid($uid) });
|
||
my $offset = $id - 100000;
|
||
my $count = $offset * 65536;
|
||
my $subordinate = 100000 + $count;
|
||
return $subordinate;
|
||
}
|
||
|
||
my @subGids;
|
||
my @subUids;
|
||
foreach my $u (values %usersOut) {
|
||
my $name = $u->{name};
|
||
|
||
foreach my $range (@{$u->{subUidRanges}}) {
|
||
my $value = join(":", ($name, $range->{startUid}, $range->{count}));
|
||
push @subUids, $value;
|
||
}
|
||
|
||
foreach my $range (@{$u->{subGidRanges}}) {
|
||
my $value = join(":", ($name, $range->{startGid}, $range->{count}));
|
||
push @subGids, $value;
|
||
}
|
||
|
||
if($u->{isNormalUser}) {
|
||
my $subordinate = allocSubUid($name);
|
||
$subUidMap->{$name} = $subordinate;
|
||
my $value = join(":", ($name, $subordinate, 65536));
|
||
push @subUids, $value;
|
||
push @subGids, $value;
|
||
}
|
||
}
|
||
|
||
updateFile("/etc/subuid", join("\n", @subUids) . "\n");
|
||
updateFile("/etc/subgid", join("\n", @subGids) . "\n");
|
||
updateFile($subUidMapFile, encode_json($subUidMap) . "\n");
|