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setup-etc.pl: Keep track of copied files

We now track copied files in /etc/.clean. This is important, because
otherwise files that are removed from environment.etc will not
actually be removed from the file system. In particular, changing
users.extraUsers.<user>.openssh.authorizedKeys.keys to an empty list
would not cause /etc/ssh/authorized_keys.d/<user> to be removed, which
was a security issue.
This commit is contained in:
Eelco Dolstra 2014-07-25 12:48:21 +02:00
parent 72af71d626
commit 7c480ad896
2 changed files with 32 additions and 11 deletions

View file

@ -132,7 +132,7 @@ in
''
# Set up the statically computed bits of /etc.
echo "setting up /etc..."
${pkgs.perl}/bin/perl ${./setup-etc.pl} ${etc}/etc
${pkgs.perl}/bin/perl -I${pkgs.perlPackages.FileSlurp}/lib/perl5/site_perl ${./setup-etc.pl} ${etc}/etc
'';
};

View file

@ -3,6 +3,7 @@ use File::Find;
use File::Copy;
use File::Path;
use File::Basename;
use File::Slurp;
my $etc = $ARGV[0] or die;
my $static = "/etc/static";
@ -46,35 +47,55 @@ sub cleanup {
find(\&cleanup, "/etc");
# Use /etc/.clean to keep track of copied files.
my @oldCopied = read_file("/etc/.clean", chomp => 1, err_mode => 'quiet');
open CLEAN, ">>/etc/.clean";
# For every file in the etc tree, create a corresponding symlink in
# /etc to /etc/static. The indirection through /etc/static is to make
# switching to a new configuration somewhat more atomic.
my %created;
my @copied;
sub link {
my $fn = substr $File::Find::name, length($etc) + 1 or next;
my $target = "/etc/$fn";
File::Path::make_path(dirname $target);
$created{$fn} = 1;
if (-e "$_.mode") {
open MODE, "<$_.mode";
my $mode = <MODE>; chomp $mode;
close MODE;
my $mode = read_file("$_.mode"); chomp $mode;
if ($mode eq "direct-symlink") {
atomicSymlink readlink("$static/$fn"), $target or warn;
} else {
open UID, "<$_.uid";
my $uid = <UID>; chomp $uid;
close UID;
open GID, "<$_.gid";
my $gid = <GID>; chomp $gid;
close GID;
my $uid = read_file("$_.uid"); chomp $uid;
my $gid = read_file("$_.gid"); chomp $gid;
copy "$static/$fn", "$target.tmp" or warn;
chown int($uid), int($gid), "$target.tmp" or warn;
chmod oct($mode), "$target.tmp" or warn;
rename "$target.tmp", $target or warn;
}
push @copied, $fn;
print CLEAN "$fn\n";
} elsif (-l "$_") {
atomicSymlink "$static/$fn", $target or warn;
}
}
find(\&link, $etc);
# Delete files that were copied in a previous version but not in the
# current.
foreach my $fn (@oldCopied) {
if (!defined $created{$fn}) {
$fn = "/etc/$fn";
print STDERR "removing obsolete file $fn...\n";
unlink "$fn";
}
}
# Rewrite /etc/.clean.
close CLEAN;
write_file("/etc/.clean", map { "$_\n" } @copied);