use strict;
-# What we do is this:
+# DGIT-REPOS-DIR contains:
+# git tree (or other object) lock (in acquisition order, outer first)
+#
+# _tmp/PACKAGE_prospective ! } SAME.lock, held during receive-pack
+#
+# _tmp/PACKAGE_incoming$$ ! } SAME.lock, held during receive-pack
+# _tmp/PACKAGE_incoming$$_fresh ! }
+#
+# PACKAGE.git } PACKAGE.git.lock
+# PACKAGE_garbage } (also covers executions of
+# PACKAGE_garbage-old } policy hook script for PACKAGE)
+# PACKAGE_garbage-tmp }
+#
+# leaf locks, held during brief operaton only:
+#
+# _empty } SAME.lock
+# _empty.new }
+#
+# _template } SAME.lock
+#
+# locks marked ! may be held during client data transfer
+
+# What we do on push is this:
# - extract the destination repo name
# - make a hardlink clone of the destination repo
# - provide the destination with a stunt pre-receive hook
# + verify the signature on the signed tag
# and if necessary check that the keyid and package are listed in dm.txt
# + check various correspondences:
-# * the suite is one of those permitted
# * the signed tag must refer to a commit
# * the signed tag commit must be the refs/dgit value
# * the name in the signed tag must correspond to its ref name
# * the tag name must be debian/<version> (massaged as needed)
+# * the suite is one of those permitted
# * the signed tag has a suitable name
-# * the commit is a fast forward
+# * run the "push" policy hook
+# * replay prevention for --deliberately-not-fast-forward
+# * check the commit is a fast forward
+# * handle a request from the policy hook for a fresh repo
# + push the signed tag and new dgit branch to the actual repo
#
# If the destination repo does not already exist, we need to make
# of _template
# - we use the prospective new destination repo instead of the
# actual new destination repo (since the latter doesn't exist)
-# - we set up a post-receive hook as well, which
-# + touches a stamp file
# - after git-receive-pack exits, we
# + check that the prospective repo contains a tag and head
# + rename the prospective destination repo into place
our @lockfhs;
our $debug='';
our @deliberatelies;
+our %supersedes;
our $policy;
#----- utilities -----
debug " locking $lock failed";
return undef;
}
- if (!stat $lock) {
- next if $! == ENOENT;
- die "stat $lock: $!";
- }
+ next unless stat_exists $lock;
my $want = (stat _)[1];
stat $fh or die $!;
my $got = (stat _)[1];
sub mkrepo_fromtemplate ($) {
my ($dir) = @_;
my $template = "$dgitrepos/_template";
- debug "copy tempalate $template -> $dir";
+ acquiretree($template,1);
+ debug "copy template $template -> $dir";
my $r = system qw(cp -a --), $template, $dir;
!$r or die "create new repo $dir failed: $r $!";
}
sub movetogarbage () {
- my $garbagerepo = "$dgitrepos/_tmp/${package}_garbage";
- acquiretree($garbagerepo,1);
- rmtree $garbagerepo;
+ # $realdestrepo must have been locked
+ my $garbagerepo = "$dgitrepos/${package}_garbage";
+ # We arrange to always keep at least one old tree, for anti-rewind
+ # purposes (and, I guess, recovery from mistakes). This is either
+ # $garbage or $garbage-old.
+ if (stat_exists "$garbagerepo") {
+ rmtree "$garbagerepo-tmp";
+ if (rename "$garbagerepo-old", "$garbagerepo-tmp") {
+ rmtree "$garbagerepo-tmp";
+ } else {
+ die "$garbagerepo $!" unless $!==ENOENT;
+ }
+ rename "$garbagerepo", "$garbagerepo-old" or die "$garbagerepo $!";
+ }
rename $realdestrepo, $garbagerepo
or $! == ENOENT
- or die "rename repo $realdestrepo to $garbagerepo: $!";
+ or die "$garbagerepo $!";
}
sub onwardpush () {
mkrepotmp();
$workrepo = "$dgitrepos/_tmp/${package}_incoming$$";
acquiretree($workrepo, 1);
+ my $lfh = acquiretree($realdestrepo, 1);
runcmd qw(git clone -l -q --mirror), $destrepo, $workrepo;
+ close $lfh;
rmtree "${workrepo}_fresh";
}
sub dealwithfreshrepo () {
my $freshrepo = "${workrepo}_fresh";
- if (!stat $freshrepo) {
- $!==ENOENT or die "$freshrepo $!";
- return;
- }
+ return unless stat_exists $freshrepo;
$destrepo = $freshrepo;
}
die Dumper(\%got)." -- missing refs in new repo"
if grep { !$_ } values %got;
- movetogarbage; # in case of FRESHREPO
+ acquiretree($realdestrepo,1);
+
+ if ($destrepo eq "${workrepo}_fresh") {
+ movetogarbage;
+ }
debug "install $destrepo => $realdestrepo";
rename $destrepo, $realdestrepo or die $!;
die "$1 != $distro" unless $1 eq $distro;
} elsif (s/^(--deliberately-$package_re) //) {
push @deliberatelies, $1;
+ } elsif (s/^supersede:(\S+)=(\w+) //) {
+ die "supersede $1 twice" if defined $supersedes{$1};
+ $supersedes{$1} = $2;
} elsif (s/^[-+.=0-9a-z]\S* //) {
} else {
die "unknown dgit info in tag";
reject "unknown suite";
}
+sub checktagnoreplay () {
+ # We check that the signed tag mentions the name and value of
+ # (a) in the case of FRESHREPO all tags in the repo;
+ # (b) in the case of just NOFFCHECK all tags referring to
+ # the current head for the suite (there must be at least one).
+ # This prevents a replay attack using an earlier signed tag.
+ return unless $policy & (FRESHREPO|NOFFCHECK);
+
+ my $garbagerepo = "$dgitrepos/${package}_garbage";
+ acquiretree($realdestrepo,1);
+
+ local $ENV{GIT_DIR};
+ foreach my $garb ("$garbagerepo", "$garbagerepo-old") {
+ if (stat_exists $garb) {
+ $ENV{GIT_DIR} = $garb;
+ last;
+ }
+ }
+ if (!defined $ENV{GIT_DIR}) {
+ # Nothing to overwrite so the FRESHREPO and NOFFCHECK were
+ # pointless. Oh well.
+ debug "checktagnoreplay - no garbage, ok";
+ return;
+ }
+
+ my $onlyreferring;
+ if (!($policy & FRESHREPO)) {
+ my $branch = server_branch($suite);
+ $!=0; $?=0; $_ =
+ `git for-each-ref --format='%(objectname)' '[r]efs/$branch'`;
+ defined or die "$branch $? $!";
+ $? and die "$branch $?";
+ if (!length) {
+ # No such branch - NOFFCHECK was unnecessary. Oh well.
+ debug "checktagnoreplay - not FRESHREPO, new branch, ok";
+ return;
+ }
+ m/^(\w+)\n$/ or die "$branch $_ ?";
+ $onlyreferring = $1;
+ debug "checktagnoreplay - not FRESHREPO,".
+ " checking for overwriting refs/$branch=$onlyreferring";
+ }
+
+ my @problems;
+
+ git_for_each_tag_referring($objreferring, sub {
+ my ($objid,$fullrefname,$tagname) = @_;
+ debug "checktagnoreplay - overwriting $fullrefname=$objid";
+ my $supers = $supersedes{$fullrefname};
+ if (!defined $supers) {
+ push @problems, "does not supersede $fullrefname";
+ } elsif ($supers ne $objid) {
+ push @problems,
+ "supersedes $fullrefname=$supers but previously $fullrefname=$objid";
+ } else {
+ # ok;
+ }
+ });
+
+ if (@problems) {
+ reject "replay attack prevention check failed:".
+ " signed tag for $version: ".
+ join("; ", @problems).
+ "\n";
+ }
+ debug "checktagnoreply - all ok"
+}
+
sub tagh1 ($) {
my ($tag) = @_;
my $vals = $tagh{$tag};
debug "translated version $v";
$tagname eq "debian/$v" or die;
+ acquiretree($realdestrepo,1);
+
$policy = policyhook(NOFFCHECK|FRESHREPO, 'push',$package,
$version,$suite,$tagname,
join(",",@delberatelies));
+ checktagnoreplay();
checksuite();
# check that our ref is being fast-forwarded
sub fixmissing__git_upload_pack () {
$destrepo = "$dgitrepos/_empty";
my $lfh = acquiretree($destrepo,1);
- return if stat $destrepo;
- die $! unless $!==ENOENT;
+ return if stat_exists $destrepo;
rmtree "$destrepo.new";
mkemptyrepo "$destrepo.new", "0644";
rename "$destrepo.new", $destrepo or die $!;
}
sub main__git_upload_pack () {
- runcmd qw(git upload-pack), $destrepo;
+ my $lfh = acquiretree($destrepo,1);
+ chdir $destrepo or die "$destrepo: $!";
+ close $lfh;
+ runcmd qw(git upload-pack), ".";
}
#----- arg parsing and main program -----
reject "unknown method" unless $mainfunc;
+ my $lfh = acquiretree($realdestrepo,1);
+
my ($policy, $pollock) = policyhook(FRESHREPO,'check-package',$package);
if ($policy & FRESHREPO) {
movetogarbage;
}
close $pollock or die $!;
- if (stat $realdestrepo) {
+ close $lfh;
+
+ if (stat_exists $realdestrepo) {
$destrepo = $realdestrepo;
} else {
- $! == ENOENT or die "stat dest repo $destrepo: $!";
debug " fixmissing $funcn";
my $fixfunc = $main::{"fixmissing__$funcn"};
&$fixfunc;
~ianmdlvl / dgit.git / blobdiff