1
0
Fork 1
mirror of https://github.com/NixOS/nixpkgs.git synced 2024-11-22 13:41:26 +00:00
nixpkgs/nixos/modules/config/update-users-groups.pl
Bjørn Forsman 6e528893a8 nixos/update-users-groups.pl: print UIDs and GIDs
Instead of showing this output from "nixos-rebuild switch":

  warning: not applying GID change of group ‘munin’
  warning: not applying UID change of user ‘ntp’

print this:

  warning: not applying GID change of group ‘munin’ (95 -> 102)
  warning: not applying UID change of user ‘ntp’ (3 -> 179)

This makes it possible for users to take action and fixup the UIDs/GIDs
that NixOS won't touch.
2016-07-01 13:13:46 +02:00

247 lines
8.1 KiB
Perl
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

use strict;
use File::Path qw(make_path);
use File::Slurp;
use JSON;
make_path("/var/lib/nixos", { mode => 0755 });
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, $idMin, $idMax, $up, $getid) = @_;
my $id = $up ? $idMin : $idMax;
while ($id >= $idMin && $id <= $idMax) {
if (!$used->{$id} && !defined &$getid($id)) {
$used->{$id} = 1;
return $id;
}
$used->{$id} = 1;
if ($up) { $id++; } else { $id--; }
}
die "$0: out of free UIDs or GIDs\n";
}
my (%gidsUsed, %uidsUsed);
sub allocGid {
return allocId(\%gidsUsed, 400, 499, 0, sub { my ($gid) = @_; getgrgid($gid) });
}
sub allocUid {
my ($isSystemUser) = @_;
my ($min, $max, $up) = $isSystemUser ? (400, 499, 0) : (1000, 29999, 1);
return allocId(\%uidsUsed, $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 already in use.
foreach my $g (@{$spec->{groups}}) {
$gidsUsed{$g->{gid}} = 1 if defined $g->{gid};
}
foreach my $u (@{$spec->{groups}}) {
$uidsUsed{$u->{u}} = 1 if defined $u->{uid};
}
# 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 if !defined $g->{gid};
$g->{password} = "x";
}
$g->{members} = join ",", sort(keys(%members));
$groupsOut{$name} = $g;
}
# Update the persistent list of declarative groups.
write_file($declGroupsFile, { binmode => ':utf8' }, 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));
write_file("/etc/group.tmp", { binmode => ':utf8' }, @lines);
rename("/etc/group.tmp", "/etc/group") or die;
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 {
$u->{uid} = allocUid($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} && ! -e $u->{home}) {
make_path($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} = $u;
}
# Update the persistent list of declarative users.
write_file($declUsersFile, { binmode => ':utf8' }, 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));
write_file("/etc/passwd.tmp", { binmode => ':utf8' }, @lines);
rename("/etc/passwd.tmp", "/etc/passwd") or die;
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
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";
}
write_file("/etc/shadow.tmp", { binmode => ':utf8', perms => 0600 }, @shadowNew);
rename("/etc/shadow.tmp", "/etc/shadow") or die;