diff options
Diffstat (limited to 'debian/local/pam-auth-update')
| -rw-r--r-- | debian/local/pam-auth-update | 715 |
1 files changed, 715 insertions, 0 deletions
diff --git a/debian/local/pam-auth-update b/debian/local/pam-auth-update new file mode 100644 index 0000000..6d17ab7 --- /dev/null +++ b/debian/local/pam-auth-update @@ -0,0 +1,715 @@ +#!/usr/bin/perl -w + +# pam-auth-update: update /etc/pam.d/common-* from /usr/share/pam-configs +# +# Update the /etc/pam.d/common-* files based on the per-package profiles +# provided in /usr/share/pam-configs/ taking into consideration user's +# preferences (as determined via debconf prompting). +# +# Written by Steve Langasek <steve.langasek@canonical.com> +# +# Copyright (C) 2008 Canonical Ltd. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of version 3 of the GNU General Public License as +# published by the Free Software Foundation. +# +# # This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, +# USA. + +use strict; +use Debconf::Client::ConfModule ':all'; +use IPC::Open2 'open2'; + +version('2.0'); +my $capb=capb('backup escape'); + +my $inputdir = '/usr/share/pam-configs'; +my $template = 'libpam-runtime/profiles'; +my $errtemplate = 'libpam-runtime/conflicts'; +my $overridetemplate = 'libpam-runtime/override'; +my $blanktemplate = 'libpam-runtime/no_profiles_chosen'; +my $titletemplate = 'libpam-runtime/title'; +my $confdir = '/etc/pam.d'; +my $savedir = '/var/lib/pam'; +my (%profiles, @sorted, @enabled, @conflicts, @new, %removals, %to_enable); +my $force = 0; +my $package = 0; +my $priority = 'high'; +my %md5sums = ( + 'auth' => ['8d4fe17e66ba25de16a117035d1396aa'], + 'account' => ['3c0c362eaf3421848b679d63fd48c3fa'], + 'password' => [ + '50fce2113dfda83ac8bdd5a6e706caec', + '4bd7610f2e85f8ddaef79c7db7cb49eb', + '9ba753d0824276b44bcadfee1f87b6bc', + ], + 'session' => [ + '240fb92986c885b327cdb21dd641da8c', + '4a25673e8b36f1805219027d3be02cd2', + ], + 'session-noninteractive' => [ + 'ad2b78ce1498dd637ef36469430b6ac6', + ], +); + +opendir(DIR, $inputdir) || die "could not open config directory: $!"; +while (my $profile = readdir(DIR)) { + next if ($profile eq '.' || $profile eq '..' || $profile =~ m/~$/ || $profile =~ m/^#.+#$/); + %{$profiles{$profile}} = parse_pam_profile($inputdir . '/' . $profile); +} +closedir DIR; + +# use a '--force' arg to specify that /etc/pam.d should be overwritten; +# used only on upgrades where the postinst has already determined that the +# checksums match. Module packages other than libpam-runtime itself must +# NEVER use this option! Document with big skullses and crossboneses! It +# needs to be exposed for libpam-runtime because that's the package that +# decides whether we have a pristine config to be converted, and knows +# whether the version being upgraded from is one for which the conversion +# should be done. + +while ($#ARGV >= 0) { + my $opt = shift; + if ($opt eq '--force') { + $force = 1; + } elsif ($opt eq '--package') { + $package = 1; + } elsif ($opt eq '--remove') { + while ($#ARGV >= 0) { + last if ($ARGV[0] =~ /^--/); + $removals{shift @ARGV} = 1; + } + # --remove implies --package + $package = 1 if (keys(%removals)); + } elsif ($opt eq '--enable') { + while ($#ARGV >= 0) { + last if ($ARGV[0] =~ /^--/); + $to_enable{shift @ARGV} = 1; + } + # --enable implies --package + $package = 1 if (keys(%to_enable)); + } +} + +$priority = 'medium' if ($package); + +x_loadtemplatefile('/var/lib/dpkg/info/libpam-runtime.templates','libpam-runtime'); + +# always sort by priority, so we have consistency and don't have to +# shuffle later +@sorted = sort { $profiles{$b}->{'Priority'} <=> $profiles{$a}->{'Priority'} + || $b cmp $a } + keys(%profiles); +# If we're being called for package removal, filter out those options here +@sorted = grep { !$removals{$_} } @sorted; + +subst($template, 'profile_names', join(', ',@sorted)); +subst($template, 'profiles', + join(', ', map { $profiles{$_}->{'Name'} } @sorted)); + +my $diff = diff_profiles($confdir,$savedir); + +if ($diff) { + @enabled = grep { !$removals{$_} } @{$diff->{'mods'}}; +} else { + @enabled = split(/, /,get($template)); +} + +# find out what we've seen, so we can ignore those defaults +my %seen; +if (-e $savedir . '/seen') { + open(SEEN,$savedir . '/seen') or die("open(${savedir}/seen) failed: $!"); + while (<SEEN>) { + chomp; + $seen{$_} = 1; + } + close(SEEN); +} + +# filter out any options that are no longer available for any reason +@enabled = grep { $profiles{$_} } @enabled; + +# an empty module set is an error, so in that case grab all the defaults +if (!@enabled) { + %seen = (); + $priority = 'high' unless ($force); +} + +# add configs to enable +push(@enabled, + grep { $to_enable{$_} } @sorted); + +# add any previously-unseen configs +push(@enabled, + grep { $profiles{$_}->{'Default'} eq 'yes' && !$seen{$_} } @sorted); +@enabled = sort { $profiles{$b}->{'Priority'} <=> $profiles{$a}->{'Priority'} + || $b cmp $a } + @enabled; +my $prev = ''; +@enabled = grep { $_ ne $prev && (($prev) = $_) } @enabled; + +# Do we have any new options to show? If not, we shouldn't reprompt the +# user, at any priority level, unless explicitly called. +@new = grep { !$seen{$_} } @sorted; + +settitle($titletemplate); + +# if diff_profiles() fails, and we weren't passed a 'force' argument +# (because this isn't an upgrade from an old version, or the checksum +# didn't match, or we're being called by some other module package), prompt +# the user whether to override. If the user declines (the default), we +# never again manage this config unless manually called with '--force'. +if (!$diff && !$force) { + input('high',$overridetemplate); + go(); + $force = 1 if (get($overridetemplate) eq 'true'); +} + +if (!$diff && !$force) { + print STDERR <<EOF; + +pam-auth-update: Local modifications to /etc/pam.d/common-*, not updating. +pam-auth-update: Run pam-auth-update --force to override. + +EOF + exit; +} + +umask(0022); + +do { + @conflicts = (); + + if (@new || !$package) { + fset($template,'seen','false'); + } + set($template,join(', ', @enabled)); + + input($priority,$template); + go(); + + @enabled = split(/, /, get($template)); + + # in case of conflicts, automatically unset the lower priority + # item of each pair + foreach my $elem (@enabled) + { + for (my $i=$#enabled; $i >= 0; $i--) + { + my $conflict = $enabled[$i]; + if ($profiles{$elem}->{'Conflicts'}->{$conflict}) { + splice(@enabled,$i,1); + my $desc = $profiles{$elem}->{'Name'} + . ', ' . $profiles{$conflict}->{'Name'}; + push(@conflicts,$desc); + } + } + } + if (@conflicts) { + subst($errtemplate, 'conflicts', join("\\n", @conflicts)); + input('high',$errtemplate); + } + set($template, join(', ', @enabled)); + if (!@enabled) { + input('high',$blanktemplate); + # we can only end up here by user error, but give them another + # shot at selecting a correct config anyway. + fset($template,'seen','false'); + } +} while (@conflicts || !@enabled); + +# the decision has been made about what configs to use, so even if +# something fails after this, we shouldn't go munging the default +# options again. Save the list of known configs to /var/lib/pam. +open(SEEN,"> $savedir/seen") or die("open(${savedir}/seen) failed: $!"); +for my $i (@sorted) { + print SEEN "$i\n"; +} +close(SEEN) or die("close(${savedir}/seen) failed: $!"); + +# @enabled now contains our list of profiles to use for piecing together +# a config +# we have: +# - templates into which we insert the specialness +# - magic comments denoting the beginning and end of our managed block; +# looking at only the functional config lines would potentially let us +# handle more cases, at the expense of much greater complexity, so +# pass on this at least for the first round +# - a representation of the autogenerated config stored in /var/lib/pam, +# that we can diff against in order to account for changed options or +# manually dropped modules +# - a hash describing the local modifications the user has made to the +# config; these are always preserved unless manually overridden with +# the --force option + +write_profiles(\%profiles, \@enabled, $confdir, $savedir, $diff, $force); + + +# take a single line from a stock config, and merge it with the +# information about local admin edits +sub merge_one_line +{ + my ($line,$diff,$count) = @_; + my (@opts,$modline); + + my ($adds,$removes); + + $line =~ /^((\[[^]]+\]|\w+)\s+\S+)\s*(.*)/; + + @opts = split(/\s+/,$3); + $modline = $1; + $modline =~ s/end/$count/g; + if ($diff) { + my $mod = $modline; + $mod =~ s/(\[[^0-9]*)[0-9]+(.*\])/$1$2/g; + $adds = \%{$diff->{'add'}{$mod}}; + $removes = \%{$diff->{'remove'}{$mod}}; + } else { + $adds = $removes = undef; + } + + for (my $i = 0; $i <= $#opts; $i++) { + if ($adds->{$opts[$i]}) { + delete $adds->{$opts[$i]}; + } + if ($removes->{$opts[$i]}) { + splice(@opts,$i,1); + $i--; + } + } + return $modline . " " . join(' ',@opts,sort keys(%{$adds})) . "\n"; +} + +# return the lines for a given config name, type, and position in the stack +sub lines_for_module_and_type +{ + my ($profiles, $mod, $type, $modpos) = @_; + if ($modpos == 0 && $profiles->{$mod}{$type . '-Initial'}) { + return $profiles->{$mod}{$type . '-Initial'}; + } + return $profiles->{$mod}{$type}; +} + +# create a single PAM config from the indicated template and selections, +# writing to a new file +sub create_from_template +{ + my($template,$dest,$profiles,$enabled,$diff,$type) = @_; + my $state = 0; + my $uctype = ucfirst($type); + $type =~ s/-noninteractive//; + + open(INPUT,$template) || return 0; + open(OUTPUT,">$dest") || return 0; + + while (<INPUT>) { + if ($state == 1) { + if (/^# here's the fallback if no module succeeds/) { + print OUTPUT; + $state++; + } + next; + } + if ($state == 3) { + if (/^# end of pam-auth-update config/) { + print OUTPUT; + $state++; + } + next; + } + + print OUTPUT; + + my ($pattern,$val); + if ($state == 0) { + $pattern = '^# here are the per-package modules \(the "Primary" block\)'; + $val = 'Primary'; + } elsif ($state == 2) { + $pattern = '^# and here are more per-package modules \(the "Additional" block\)'; + $val = 'Additional'; + } else { + next; + } + + if (/$pattern/) { + my $i = 0; + my $count = 0; + # first we need to get a count of lines that we're + # going to output, so we can fix up the jumps correctly + for my $mod (@{$enabled}) { + my $output; + next if (!$profiles->{$mod}{$uctype . '-Type'}); + next if $profiles->{$mod}{$uctype . '-Type'} ne $val; + $output = lines_for_module_and_type($profiles, $mod, $uctype, $i++); + # bypasses a perl warning about @_, sigh + my @tmparr = split("\n+",$output); + $count += @tmparr; + } + + # in case anything tries to jump in the 'additional' + # block, let's try not to jump off the stack... + $count-- if ($val eq 'Additional'); + + # no primary block, so output a stock pam_permit line + # to keep the stack intact + if ($val eq 'Primary' && $count == 0) + { + print OUTPUT "$type\t[default=1]\t\t\tpam_permit.so\n"; + } + + $i = 0; + for my $mod (@{$enabled}) { + my $output; + my @output; + next if (!$profiles->{$mod}{$uctype . '-Type'}); + next if $profiles->{$mod}{$uctype . '-Type'} ne $val; + $output = lines_for_module_and_type($profiles, $mod, $uctype, $i++); + for my $line (split("\n",$output)) { + $line = merge_one_line($line,$diff, + $count); + print OUTPUT "$type\t$line"; + $count--; + } + } + $state++; + } + } + close(INPUT); + close(OUTPUT) or die("close($dest) failed: $!"); + + if ($state < 4) { + unlink($dest); + return 0; + } + return 1; +} + +# take a template file, strip out everything between the markers, and +# return the md5sum of the remaining contents. Used for testing for +# local modifications of the boilerplate. +sub get_template_md5sum +{ + my($template) = @_; + my $state = 0; + + open(INPUT,$template) || return ''; + my($md5sum_fd,$output_fd); + my $pid = open2($md5sum_fd, $output_fd, 'md5sum'); + return '' if (!$pid); + + while (<INPUT>) { + if ($state == 1) { + if (/^# here's the fallback if no module succeeds/) { + print $output_fd $_; + $state++; + } + next; + } + if ($state == 3) { + if (/^# end of pam-auth-update config/) { + print $output_fd $_; + $state++; + } + next; + } + + print $output_fd $_; + + my ($pattern,$val); + if ($state == 0) { + $pattern = '^# here are the per-package modules \(the "Primary" block\)'; + } elsif ($state == 2) { + $pattern = '^# and here are more per-package modules \(the "Additional" block\)'; + } else { + next; + } + + if (/$pattern/) { + $state++; + } + } + close(INPUT); + close($output_fd); + my $md5sum = <$md5sum_fd>; + close($md5sum_fd); + waitpid $pid, 0; + + $md5sum = (split(/\s+/,$md5sum))[0]; + return $md5sum; +} + +# merge a set of module declarations into a set of new config files, +# using the information returned from diff_profiles(). +sub write_profiles +{ + my($profiles,$enabled,$confdir,$savedir,$diff,$force) = @_; + + if (! -d $savedir) { + mkdir($savedir); + } + + # because we can't atomically replace both /var/lib/pam/$foo and + # /etc/pam.d/common-$foo at the same time, take steps to make this + # somewhat robust + for my $type ('auth','account','password','session', + 'session-noninteractive') + { + my $target = $confdir . '/common-' . $type; + my $template = $target; + my $dest = $template . '.pam-new'; + + my $diff = $diff; + if ($diff) { + $diff = \%{$diff->{$type}}; + } + + # Detect if the template is unmodified, and if so, use + # the version from /usr/share. Depends on knowing the + # md5sums of the originals. + my $md5sum = get_template_md5sum($template); + for my $i (@{$md5sums{$type}}) { + if ($md5sum eq $i) { + $template = '/usr/share/pam/common-' . $type; + last; + } + } + + # first, write out the new config + if (!create_from_template($template,$dest,$profiles,$enabled, + $diff,$type)) + { + if (!$force) { + return 0; + } + $template = '/usr/share/pam/common-' . $type; + if (!create_from_template($template,$dest,$profiles, + $enabled,$diff,$type)) + { + return 0; + } + } + + # then write out the saved config + if (!open(OUTPUT, "> $savedir/$type.new")) { + unlink($dest); + return 0; + } + my $i = 0; + my $uctype = ucfirst($type); + for my $mod (@{$enabled}) { + my $output; + next if (!$profiles->{$mod}{$uctype . '-Type'}); + next if ($profiles->{$mod}{$uctype . '-Type'} eq 'Additional'); + + $output = lines_for_module_and_type($profiles, $mod, $uctype, $i++); + if ($output) { + print OUTPUT "Module: $mod\n"; + print OUTPUT $output . "\n"; + } + } + + # no primary block, so output a stock pam_permit line + if ($i == 0) + { + print OUTPUT "Module: null\n"; + print OUTPUT "[default=1]\t\t\tpam_permit.so\n"; + } + + $i = 0; + for my $mod (@{$enabled}) { + my $output; + next if (!$profiles->{$mod}{$uctype . '-Type'}); + next if ($profiles->{$mod}{$uctype . '-Type'} eq 'Primary'); + + $output = lines_for_module_and_type($profiles, $mod, $uctype, $i++); + if ($output) { + print OUTPUT "Module: $mod\n"; + print OUTPUT $output . "\n"; + } + } + + close(OUTPUT) or die("close($dest) failed: $!"); + + # then do the renames, back-to-back + # we have to use system because File::Copy is in + # perl-modules, not perl-base + if (-e $target && $force) { + system('cp','-f',$target,$target . '.pam-old') == 0 + or die("cp -f ${target} ${target}.pam.old failed"); + } + rename($dest,$target) + or die("rename($dest, $target) failed: $!"); + rename("$savedir/${type}.new","$savedir/$type") + or die("rename(${savedir}/${type}.new, ${savedir}/${type}) failed: $!"); + } + + # at the end of a successful write, reset the 'seen' flag and the + # value of the debconf override question. + fset($overridetemplate,'seen','false'); + set($overridetemplate,'false'); +} + +# reconcile the current config in /etc/pam.d with the saved ones in +# /var/lib/pam; returns a hash of profile names and the corresponding +# options that should be added/removed relative to the stock config. +# returns false if any of the markers are missing that permit a merge, +# or on any other failure. +sub diff_profiles +{ + my ($sourcedir,$savedir) = @_; + my (%diff); + + @{$diff{'mods'}} = (); + # Load the saved config from /var/lib/pam, then iterate through all + # lines in the current config that are in the managed block. + # If anything fails here, just return immediately since we then + # have nothing to merge; instead, the caller will decide later + # whether to force an overwrite. + for my $type ('auth','account','password','session', + 'session-noninteractive') + { + my (@saved,$modname); + + open(SAVED,$savedir . '/' . $type) || return 0; + while (<SAVED>) { + if (/^Module: (.*)/) { + $modname = $1; + next; + } + chomp; + # trim out the destination of any jumps; this saves + # us from having to re-parse everything just to fix + # up the jump lengths, when changes to these will + # already show up as inconsistencies elsewhere + s/(\[[^0-9]*)[0-9]+(.*\])/$1$2/g; + s/(\[.*)end(.*\])/$1$2/g; + my (@temp) = ($modname,$_); + push(@saved,\@temp); + } + close(SAVED); + + my $state = 0; + my (@prev_opts,$curmod); + my $realtype = $type; + $realtype =~ s/-noninteractive//; + + open(CURRENT,$sourcedir . '/common-' . $type) || return 0; + while (<CURRENT>) { + if ($state == 0) { + $state = 1 + if (/^# here are the per-package modules \(the "Primary" block\)/); + next; + } + if ($state == 1) { + s/^$realtype\s+//; + if (/^# here's the fallback if no module succeeds/) { + $state = 2; + next; + } + } + if ($state == 2) { + $state = 3 + if (/^# and here are more per-package modules \(the "Additional" block\)/); + next; + } + if ($state == 3) { + last if (/^# end of pam-auth-update config/); + s/^$realtype\s+//; + } + + my $found = 0; + my $curopts; + while (!$found && $#saved >= 0) { + my $line; + ($modname,$line) = @{$saved[0]}; + shift(@saved); + $line =~ /^((\[[^]]+\]|\w+)\s+\S+)\s*(.*)/; + @prev_opts = split(/\s+/,$3); + $curmod = $1; + # FIXME: the key isn't derived from the config + # name, so collisions are possible if more + # than one config references the same module + + $_ =~ s/(\[[^0-9]*)[0-9]+(.*\])/$1$2/g; + # check if this is a match for the current line + if ($_ =~ /^\Q$curmod\E\s*(.*)$/) { + $found = 1; + $curopts = $1; + push(@{$diff{'mods'}},$modname); + } + } + + # there's a line in the live config that doesn't + # correspond to anything from the saved config. + # treat this as a failure; it's very error-prone + # to decide what to do with an added line that + # didn't come from a package. + return 0 if (!$found); + + for my $opt (split(/\s+/,$curopts)) { + my $found = 0; + for (my $i = 0; $i <= $#prev_opts; $i++) { + if ($prev_opts[$i] eq $opt) { + $found = 1; + splice(@prev_opts,$i,1); + } + } + $diff{$type}{'add'}{$curmod}{$opt} = 1 if (!$found); + } + for my $opt (@prev_opts) { + $diff{$type}{'remove'}{$curmod}{$opt} = 1; + } + } + close(CURRENT); + + # we couldn't parse the config, so the merge fails + return 0 if ($state < 3); + } + return \%diff; +} + +# simple function to parse a provided config file, in pseudo-RFC822 +# format, +sub parse_pam_profile +{ + my ($profile) = $_[0]; + my $fieldname; + my %profile; + open(PROFILE, $profile) || die "could not read profile $profile: $!"; + while (<PROFILE>) { + if (/^(\S+):\s+(.*)\s*$/) { + $fieldname = $1; + # compatibility with the first implementation round; + # "Auth-Final" is now just called "Auth" + $fieldname =~ s/-Final$//; + if ($fieldname eq 'Conflicts') { + foreach my $elem (split(/, /, $2)) { + $profile{'Conflicts'}->{$elem} = 1; + } + } else { + $profile{$fieldname} = $2; + } + } else { + chomp; + s/^\s+//; + s/\s+$//; + $profile{$fieldname} .= "\n$_" if ($_); + $profile{$fieldname} =~ s/^[\n\s]+//; + } + } + close(PROFILE); + if (!defined($profile{'Session-Interactive-Only'})) { + $profile{'Session-noninteractive-Type'} = $profile{'Session-Type'}; + $profile{'Session-noninteractive'} = $profile{'Session'}; + $profile{'Session-noninteractive-Initial'} = $profile{'Session-Initial'}; + } + return %profile; +} |