5 # dgit-repos-server DISTRO DISTRO-DIR AUTH-SPEC [<settings>] --ssh
6 # dgit-repos-server DISTRO DISTRO-DIR AUTH-SPEC [<settings>] --cron
8 # --repos=GIT-REPOS-DIR default DISTRO-DIR/repos/
9 # --suites=SUITES-FILE default DISTRO-DIR/suites
10 # --policy-hook=POLICY-HOOK default DISTRO-DIR/policy-hook
11 # --dgit-live=DGIT-LIVE-DIR default DISTRO-DIR/dgit-live
12 # (DISTRO-DIR is not used other than as default)
14 # .../dgit-repos-server --pre-receive-hook PACKAGE
16 # Invoked as the ssh restricted command
18 # Works like git-receive-pack
20 # SUITES is the name of a file which lists the permissible suites
21 # one per line (#-comments and blank lines ignored)
23 # AUTH-SPEC is a :-separated list of
24 # KEYRING.GPG,AUTH-SPEC
25 # where AUTH-SPEC is one of
30 $SIG{__WARN__} = sub { die $_[0]; };
32 # DGIT-REPOS-DIR contains:
33 # git tree (or other object) lock (in acquisition order, outer first)
35 # _tmp/PACKAGE_prospective ! } SAME.lock, held during receive-pack
37 # _tmp/PACKAGE_incoming$$ ! } SAME.lock, held during receive-pack
38 # _tmp/PACKAGE_incoming$$_fresh ! }
40 # PACKAGE.git } PACKAGE.git.lock
41 # PACKAGE_garbage } (also covers executions of
42 # PACKAGE_garbage-old } policy hook script for PACKAGE)
43 # PACKAGE_garbage-tmp }
44 # policy* } (for policy hook script, covered by
45 # } lock only when invoked for a package)
47 # leaf locks, held during brief operaton only:
52 # _template } SAME.lock
54 # locks marked ! may be held during client data transfer
56 # What we do on push is this:
57 # - extract the destination repo name
58 # - make a hardlink clone of the destination repo
59 # - provide the destination with a stunt pre-receive hook
60 # - run actual git-receive-pack with that new destination
61 # as a result of this the stunt pre-receive hook runs; it does this:
62 # + understand what refs we are allegedly updating and
63 # check some correspondences:
64 # * we are updating only refs/tags/debian/* and refs/dgit/*
65 # * and only one of each
66 # * and the tag does not already exist
68 # * recover the suite name from the destination refs/dgit/ ref
69 # + disassemble the signed tag into its various fields and signature
71 # * parsing the first line of the tag message to recover
72 # the package name, version and suite
73 # * checking that the package name corresponds to the dest repo name
74 # * checking that the suite name is as recovered above
75 # + verify the signature on the signed tag
76 # and if necessary check that the keyid and package are listed in dm.txt
77 # + check various correspondences:
78 # * the signed tag must refer to a commit
79 # * the signed tag commit must be the refs/dgit value
80 # * the name in the signed tag must correspond to its ref name
81 # * the tag name must be debian/<version> (massaged as needed)
82 # * the suite is one of those permitted
83 # * the signed tag has a suitable name
84 # * run the "push" policy hook
85 # * replay prevention for --deliberately-not-fast-forward
86 # * check the commit is a fast forward
87 # * handle a request from the policy hook for a fresh repo
88 # + push the signed tag and new dgit branch to the actual repo
90 # If the destination repo does not already exist, we need to make
91 # sure that we create it reasonably atomically, and also that
92 # we don't every have a destination repo containing no refs at all
93 # (because such a thing causes git-fetch-pack to barf). So then we
94 # do as above, except:
95 # - before starting, we take out our own lock for the destination repo
96 # - we create a prospective new destination repo by making a copy
98 # - we use the prospective new destination repo instead of the
99 # actual new destination repo (since the latter doesn't exist)
100 # - after git-receive-pack exits, we
101 # + check that the prospective repo contains a tag and head
102 # + rename the prospective destination repo into place
105 # - We are crash-only
106 # - Temporary working trees and their locks are cleaned up
107 # opportunistically by a program which tries to take each lock and
108 # if successful deletes both the tree and the lockfile
109 # - Prospective working trees and their locks are cleaned up by
110 # a program which tries to take each lock and if successful
111 # deletes any prospective working tree and the lock (but not
112 # of course any actual tree)
113 # - It is forbidden to _remove_ the lockfile without removing
114 # the corresponding temporary tree, as the lockfile is also
115 # a stampfile whose presence indicates that there may be
118 # Policy hook script is invoked like this:
119 # POLICY-HOOK-SCRIPT DISTRO DGIT-REPOS-DIR DGIT-LIVE-DIR ACTION...
121 # POLICY-HOOK-SCRIPT ... check-list [...]
122 # POLICY-HOOK-SCRIPT ... check-package PACKAGE [...]
123 # POLICY-HOOK-SCRIPT ... push|push-confirm PACKAGE \
124 # VERSION SUITE TAGNAME DELIBERATELIES [...]
126 # Exit status is a bitmask. Bit weight constants are defined in Dgit.pm.
128 # suppress dgit-repos-server's fast-forward check ("push" only)
130 # blow away repo right away (ie, as if before push or fetch)
131 # ("check-package" and "push" only)
132 # any unexpected bits mean failure, and then known set bits are ignored
133 # if no unexpected bits set, operation continues (subject to meaning
134 # of any expected bits set). So, eg, exit 0 means "continue normally"
135 # and would be appropriate for an unknown action.
137 # cwd for push and push-confirm is a temporary repo where the
138 # to-be-pushed objects have been received; TAGNAME is the
141 # if push requested FRESHREPO, push-confirm happens in said fresh repo
143 # policy hook for a particular package will be invoked only once at
144 # a time - (see comments about DGIT-REPOS-DIR, above)
146 # check-list and check-package are invoked via the --cron option.
147 # First, without any locking, check-list is called. It should produce
148 # a list of package names. Then check-package will be invoked for
149 # each named package, in each case after taking an appropriate lock.
151 # If policy hook wants to run dgit (or something else in the dgit
152 # package), it should use DGIT-LIVE-DIR/dgit (etc.)
156 use Fcntl qw(:flock);
157 use File::Path qw(rmtree);
159 use Debian::Dgit qw(:DEFAULT :policyflags);
161 open DEBUG, ">/dev/null" or die $!;
179 #----- utilities -----
182 print DEBUG "$debug @_\n";
185 sub realdestrepo () { "$dgitrepos/$package.git"; }
187 sub acquirelock ($$) {
188 my ($lock, $must) = @_;
190 printf DEBUG "$debug locking %s %d\n", $lock, $must;
193 $fh = new IO::File $lock, ">" or die "open $lock: $!";
194 my $ok = flock $fh, $must ? LOCK_EX : (LOCK_EX|LOCK_NB);
196 die "flock $lock: $!" if $must;
197 debug " locking $lock failed";
200 next unless stat_exists $lock;
201 my $want = (stat _)[1];
203 my $got = (stat _)[1];
204 last if $got == $want;
209 sub acquirermtree ($$) {
210 my ($tree, $must) = @_;
211 my $fh = acquirelock("$tree.lock", $must);
219 sub locksometree ($) {
221 acquirelock("$tree.lock", 1);
224 sub lockrealtree () {
225 locksometree(realdestrepo);
229 my $tmpdir = "$dgitrepos/_tmp";
230 return if mkdir $tmpdir;
231 return if $! == EEXIST;
235 sub recorderror ($) {
237 my $w = $ENV{'DGIT_DRS_WORK'}; # we are in stunthook
240 open ERR, ">", "$w/drs-error" or die $!;
241 print ERR $why, "\n" or die $!;
250 recorderror "reject: $why";
251 die "dgit-repos-server: reject: $why\n";
257 local $Data::Dumper::Indent = 0;
258 local $Data::Dumper::Terse = 1;
259 debug "|".Dumper(\@_);
267 die "@_ $? $!" if $r;
271 my ($policyallowbits, @polargs) = @_;
272 # => ($exitstatuspolicybitmap);
273 die if $policyallowbits & ~0x3e;
274 my @cmd = ($policyhook,$distro,$dgitrepos,$dgitlive,@polargs);
277 die "system: $!" if $r < 0;
278 die "hook (@cmd) failed ($?)" if $r & ~($policyallowbits << 8);
279 debug sprintf "hook (%s) => %#x", "@polargs", $r;
283 sub mkemptyrepo ($$) {
284 my ($dir,$sharedperm) = @_;
285 runcmd qw(git init --bare --quiet), "--shared=$sharedperm", $dir;
288 sub mkrepo_fromtemplate ($) {
290 my $template = "$dgitrepos/_template";
291 locksometree($template);
292 debug "copy template $template -> $dir";
293 my $r = system qw(cp -a --), $template, $dir;
294 !$r or die "create new repo $dir failed: $r $!";
297 sub movetogarbage () {
298 # realdestrepo must have been locked
299 my $garbagerepo = "$dgitrepos/${package}_garbage";
300 # We arrange to always keep at least one old tree, for anti-rewind
301 # purposes (and, I guess, recovery from mistakes). This is either
302 # $garbage or $garbage-old.
303 if (stat_exists "$garbagerepo") {
304 rmtree "$garbagerepo-tmp";
305 if (rename "$garbagerepo-old", "$garbagerepo-tmp") {
306 rmtree "$garbagerepo-tmp";
308 die "$garbagerepo $!" unless $!==ENOENT;
310 rename "$garbagerepo", "$garbagerepo-old" or die "$garbagerepo $!";
312 rename realdestrepo, $garbagerepo
314 or die "$garbagerepo $!";
317 #----- git-receive-pack -----
319 sub fixmissing__git_receive_pack () {
321 $destrepo = "$dgitrepos/_tmp/${package}_prospective";
322 acquirermtree($destrepo, 1);
323 mkrepo_fromtemplate($destrepo);
326 sub makeworkingclone () {
328 $workrepo = "$dgitrepos/_tmp/${package}_incoming$$";
329 acquirermtree($workrepo, 1);
330 my $lfh = lockrealtree();
331 runcmd qw(git clone -l -q --mirror), $destrepo, $workrepo;
333 rmtree "${workrepo}_fresh";
336 sub setupstunthook () {
337 my $prerecv = "$workrepo/hooks/pre-receive";
338 my $fh = new IO::File $prerecv, O_WRONLY|O_CREAT|O_TRUNC, 0777
339 or die "$prerecv: $!";
340 print $fh <<END or die "$prerecv: $!";
343 exec $0 --pre-receive-hook $package
345 close $fh or die "$prerecv: $!";
346 $ENV{'DGIT_DRS_WORK'}= $workrepo;
347 $ENV{'DGIT_DRS_DEST'}= $destrepo;
348 debug " stunt hook set up $prerecv";
351 sub dealwithfreshrepo () {
352 my $freshrepo = "${workrepo}_fresh";
353 return unless stat_exists $freshrepo;
354 $destrepo = $freshrepo;
357 sub maybeinstallprospective () {
358 return if $destrepo eq realdestrepo;
360 if (open REJ, "<", "$workrepo/drs-error") {
363 REJ->error and die $!;
367 $!==&ENOENT or die $!;
370 debug " show-ref ($destrepo) ...";
372 my $child = open SR, "-|";
373 defined $child or die $!;
375 chdir $destrepo or die $!;
376 exec qw(git show-ref);
379 my %got = qw(tag 0 head 0);
382 debug " show-refs| $_";
383 s/^\S*[1-9a-f]\S* (\S+)$/$1/ or die;
385 m{^refs/tags/} ? 'tag' :
386 m{^refs/dgit/} ? 'head' :
390 $!=0; $?=0; close SR or $?==256 or die "$? $!";
392 debug "installprospective ?";
393 die Dumper(\%got)." -- missing refs in new repo"
394 if grep { !$_ } values %got;
398 if ($destrepo eq "${workrepo}_fresh") {
402 debug "install $destrepo => ".realdestrepo;
403 rename $destrepo, realdestrepo or die $!;
404 remove "$destrepo.lock" or die $!;
407 sub main__git_receive_pack () {
410 runcmd qw(git receive-pack), $workrepo;
412 maybeinstallprospective();
415 #----- stunt post-receive hook -----
417 our ($tagname, $tagval, $suite, $oldcommit, $commit);
418 our ($version, %tagh);
421 debug " updates ...";
425 m/^(\S+) (\S+) (\S+)$/ or die "$_ ?";
426 my ($old, $sha1, $refname) = ($1, $2, $3);
427 if ($refname =~ m{^refs/tags/(?=debian/)}) {
428 reject "pushing multiple tags!" if defined $tagname;
431 reject "tag $tagname already exists -".
432 " not replacing previously-pushed version"
434 } elsif ($refname =~ m{^refs/dgit/}) {
435 reject "pushing multiple heads!" if defined $suite;
440 reject "pushing unexpected ref!";
443 STDIN->error and die $!;
445 reject "push is missing tag ref update" unless defined $tagname;
446 reject "push is missing head ref update" unless defined $suite;
447 debug " updates ok.";
451 debug " parsetag...";
452 open PT, ">dgit-tmp/plaintext" or die $!;
453 open DS, ">dgit-tmp/plaintext.asc" or die $!;
454 open T, "-|", qw(git cat-file tag), $tagval or die $!;
456 $!=0; $_=<T>; defined or die $!;
458 if (m/^(\S+) (.*)/) {
459 push @{ $tagh{$1} }, $2;
466 $!=0; $_=<T>; defined or die $!;
467 m/^($package_re) release (\S+) for \S+ \((\S+)\) \[dgit\]$/ or
468 reject "tag message not in expected format";
470 die unless $1 eq $package;
472 die "$3 != $suite " unless $3 eq $suite;
476 print PT $copyl or die $!;
477 $!=0; $_=<T>; defined or die "missing signature? $!";
479 if (m/^\[dgit ([^"].*)\]$/) { # [dgit "something"] is for future
482 if (s/^distro\=(\S+) //) {
483 die "$1 != $distro" unless $1 eq $distro;
484 } elsif (s/^(--deliberately-$package_re) //) {
485 push @deliberatelies, $1;
486 } elsif (s/^supersede:(\S+)=(\w+) //) {
487 die "supersede $1 twice" if defined $supersedes{$1};
488 $supersedes{$1} = $2;
489 } elsif (s/^[-+.=0-9a-z]\S* //) {
491 die "unknown dgit info in tag ($_)";
496 last if m/^-----BEGIN PGP/;
507 debug " parsetag ok.";
510 sub checksig_keyring ($) {
511 my ($keyringfile) = @_;
512 # returns primary-keyid if signed by a key in this keyring
514 # or dies on other errors
518 debug " checksig keyring $keyringfile...";
520 our @cmd = (qw(gpgv --status-fd=1 --keyring),
522 qw(dgit-tmp/plaintext.asc dgit-tmp/plaintext));
529 next unless s/^\[GNUPG:\] //;
531 debug " checksig| $_";
532 my @l = split / /, $_;
533 if ($l[0] eq 'NO_PUBKEY') {
535 } elsif ($l[0] eq 'VALIDSIG') {
537 $sigtype eq '00' or reject "signature is not of type 00!";
539 die unless defined $ok;
545 debug sprintf " checksig ok=%d", !!$ok;
550 sub dm_txt_check ($$) {
551 my ($keyid, $dmtxtfn) = @_;
552 debug " dm_txt_check $keyid $dmtxtfn";
553 open DT, '<', $dmtxtfn or die "$dmtxtfn $!";
555 m/^fingerprint:\s+$keyid$/oi
557 if (s/^allow:/ /i..0) {
560 or reject "key $keyid missing Allow section in permissions!";
565 or reject "package $package not allowed for key $keyid";
570 debug " dm_txt_check allow| $_";
571 foreach my $p (split /\s+/) {
572 if ($p eq $package) {
574 debug " dm_txt_check ok";
579 DT->error and die $!;
581 reject "key $keyid not in permissions list although in keyring!";
585 foreach my $kas (split /:/, $keyrings) {
586 debug "verifytag $kas...";
587 $kas =~ s/^([^,]+),// or die;
588 my $keyid = checksig_keyring $1;
589 if (defined $keyid) {
590 if ($kas =~ m/^a$/) {
591 debug "verifytag a ok";
593 } elsif ($kas =~ m/^m([^,]+)$/) {
594 dm_txt_check($keyid, $1);
595 debug "verifytag m ok";
602 reject "key not found in keyrings";
606 debug "checksuite ($suitesfile)";
607 open SUITES, "<", $suitesfile or die $!;
613 return if $_ eq $suite;
615 die $! if SUITES->error;
616 reject "unknown suite";
619 sub checktagnoreplay () {
620 # We check that the signed tag mentions the name and value of
621 # (a) in the case of FRESHREPO all tags in the repo;
622 # (b) in the case of just NOFFCHECK all tags referring to
623 # the current head for the suite (there must be at least one).
624 # This prevents a replay attack using an earlier signed tag.
625 return unless $policy & (FRESHREPO|NOFFCHECK);
627 my $garbagerepo = "$dgitrepos/${package}_garbage";
631 foreach my $garb ("$garbagerepo", "$garbagerepo-old") {
632 if (stat_exists $garb) {
633 $ENV{GIT_DIR} = $garb;
637 if (!defined $ENV{GIT_DIR}) {
638 # Nothing to overwrite so the FRESHREPO and NOFFCHECK were
639 # pointless. Oh well.
640 debug "checktagnoreplay - no garbage, ok";
645 if (!($policy & FRESHREPO)) {
646 my $branch = server_branch($suite);
648 `git for-each-ref --format='%(objectname)' '[r]efs/$branch'`;
649 defined or die "$branch $? $!";
650 $? and die "$branch $?";
652 # No such branch - NOFFCHECK was unnecessary. Oh well.
653 debug "checktagnoreplay - not FRESHREPO, new branch, ok";
656 m/^(\w+)\n$/ or die "$branch $_ ?";
658 debug "checktagnoreplay - not FRESHREPO,".
659 " checking for overwriting refs/$branch=$onlyreferring";
664 git_for_each_tag_referring($onlyreferring, sub {
665 my ($objid,$fullrefname,$tagname) = @_;
666 debug "checktagnoreplay - overwriting $fullrefname=$objid";
667 my $supers = $supersedes{$fullrefname};
668 if (!defined $supers) {
669 push @problems, "does not supersede $fullrefname";
670 } elsif ($supers ne $objid) {
672 "supersedes $fullrefname=$supers but previously $fullrefname=$objid";
679 reject "replay attack prevention check failed:".
680 " signed tag for $version: ".
681 join("; ", @problems).
684 debug "checktagnoreply - all ok"
689 my $vals = $tagh{$tag};
690 reject "missing header $tag in signed tag object" unless $vals;
691 reject "multiple headers $tag in signed tag object" unless @$vals == 1;
698 tagh1('type') eq 'commit' or reject "tag refers to wrong kind of object";
699 tagh1('object') eq $commit or reject "tag refers to wrong commit";
700 tagh1('tag') eq $tagname or reject "tag name in tag is wrong";
705 debug "translated version $v";
706 $tagname eq "debian/$v" or die;
710 my @policy_args = ($package,$version,$suite,$tagname,
711 join(",",@deliberatelies));
712 $policy = policyhook(NOFFCHECK|FRESHREPO, 'push', @policy_args);
717 # check that our ref is being fast-forwarded
718 debug "oldcommit $oldcommit";
719 if (!($policy & NOFFCHECK) && $oldcommit =~ m/[^0]/) {
720 $?=0; $!=0; my $mb = `git merge-base $commit $oldcommit`;
722 $mb eq $oldcommit or reject "not fast forward on dgit branch";
725 if ($policy & FRESHREPO) {
726 # This is troublesome. We have been asked by the policy hook
727 # to receive the push into a fresh repo. But of course we
728 # have actually already mostly received the push into the working
729 # repo. (This is unavoidable because the instruction to use a new
730 # repo comes ultimately from the signed tag for the dgit push,
731 # which has to have been received into some repo.)
733 # So what we do is generate a fresh working repo right now and
734 # push the head and tag into it. The presence of this fresh
735 # working repo is detected by the parent, which responds by
736 # making a fresh master repo from the template.
738 $destrepo = "${workrepo}_fresh"; # workrepo lock covers
739 mkrepo_fromtemplate $destrepo;
742 policyhook(0, 'push-confirm', @policy_args);
746 my @cmd = (qw(git send-pack), $destrepo);
747 push @cmd, qw(--force) if $policy & NOFFCHECK;
748 push @cmd, "$commit:refs/dgit/$suite",
749 "$tagval:refs/tags/$tagname";
753 !$r or die "onward push to $destrepo failed: $r $!";
758 chdir $workrepo or die "chdir $workrepo: $!";
759 mkdir "dgit-tmp" or $!==EEXIST or die $!;
765 debug "stunthook done.";
768 #----- git-upload-pack -----
770 sub fixmissing__git_upload_pack () {
771 $destrepo = "$dgitrepos/_empty";
772 my $lfh = locksometree($destrepo);
773 return if stat_exists $destrepo;
774 rmtree "$destrepo.new";
775 mkemptyrepo "$destrepo.new", "0644";
776 rename "$destrepo.new", $destrepo or die $!;
777 unlink "$destrepo.lock" or die $!;
781 sub main__git_upload_pack () {
782 my $lfh = locksometree($destrepo);
783 chdir $destrepo or die "$destrepo: $!";
785 runcmd qw(git upload-pack), ".";
788 #----- arg parsing and main program -----
798 # keys are used for DGIT_DRS_XXX too
799 'repos' => \$dgitrepos,
800 'suites' => \$suitesfile,
801 'policy-hook' => \$policyhook,
802 'dgit-live' => \$dgitlive,
805 our @hookenvs = qw(distro suitesfile policyhook dgitlive keyrings dgitrepos);
807 # workrepo and destrepo handled ad-hoc
812 my $cmd = $ENV{'SSH_ORIGINAL_COMMAND'};
822 or reject "command string not understood";
828 my $mainfunc = $main::{"main__$funcn"};
830 reject "unknown method" unless $mainfunc;
832 my $lfh = lockrealtree();
834 $policy = policyhook(FRESHREPO,'check-package',$package);
835 if ($policy & FRESHREPO) {
841 if (stat_exists realdestrepo) {
842 $destrepo = realdestrepo;
844 debug " fixmissing $funcn";
845 my $fixfunc = $main::{"fixmissing__$funcn"};
849 debug " running main $funcn";
853 sub parseargsdispatch () {
856 delete $ENV{'GIT_DIR'}; # if not run via ssh, our parent git process
857 delete $ENV{'GIT_PREFIX'}; # sets these and they mess things up
859 if ($ENV{'DGIT_DRS_DEBUG'}) {
861 open DEBUG, ">&STDERR" or die $!;
864 if ($ARGV[0] eq '--pre-receive-hook') {
865 if ($debug) { $debug.="="; }
868 $package = shift @ARGV;
869 ${ $main::{$_} } = $ENV{"DGIT_DRS_\U$_"} foreach @hookenvs;
870 defined($workrepo = $ENV{'DGIT_DRS_WORK'}) or die;
871 defined($destrepo = $ENV{'DGIT_DRS_DEST'}) or die;
872 open STDOUT, ">&STDERR" or die $!;
877 recorderror "$@" or die;
883 $distro = $ENV{'DGIT_DRS_DISTRO'} = argval();
884 my $distrodir = argval();
885 $keyrings = $ENV{'DGIT_DRS_KEYRINGS'} = argval();
887 foreach my $dk (keys %indistrodir) {
888 ${ $indistrodir{$dk} } = "$distrodir/$dk";
891 while (@ARGV && $ARGV[0] =~ m/^--([-0-9a-z]+)=/ && $indistrodir{$1}) {
892 ${ $indistrodir{$1} } = $'; #';
896 $ENV{"DGIT_DRS_\U$_"} = ${ $main::{$_} } foreach @hookenvs;
900 my $mode = shift @ARGV;
901 die unless $mode =~ m/^--(\w+)$/;
902 my $fn = ${*::}{"mode_$1"};
908 while (my $fh = pop @lockfhs) { close $fh; }
913 if (!chdir "$dgitrepos/_tmp") {
914 $!==ENOENT or die $!;
917 foreach my $lf (<*.lock>) {
919 $tree =~ s/\.lock$//;
920 next unless acquirermtree($tree, 0);
921 remove $lf or warn $!;