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authorIan Jackson <ijackson@chiark.greenend.org.uk>2015-03-21 14:56:24 +0000
committerIan Jackson <ijackson@chiark.greenend.org.uk>2015-03-22 15:20:29 +0000
commit4487fc3517fb6db0dd8f25199cc0654c026d203d (patch)
tree781ad9122350617c99a6f695ed8ecc7f00a74924 /infra/dgit-repos-server
parentfb568448c56dc58293d9b7a817f25ef1fa082efc (diff)
Support --deliberately-not-fast-forward
Diffstat (limited to 'infra/dgit-repos-server')
-rwxr-xr-xinfra/dgit-repos-server93
1 files changed, 89 insertions, 4 deletions
diff --git a/infra/dgit-repos-server b/infra/dgit-repos-server
index d2f94f1..551efff 100755
--- a/infra/dgit-repos-server
+++ b/infra/dgit-repos-server
@@ -103,6 +103,7 @@ our $keyrings;
our @lockfhs;
our $debug='';
our @deliberatelies;
+our %supersedes;
our $policy;
#----- utilities -----
@@ -211,12 +212,24 @@ sub mkrepo_fromtemplate ($) {
}
sub movetogarbage () {
- my $garbagerepo = "$dgitrepos/_tmp/${package}_garbage";
- acquiretree($garbagerepo,1);
- rmtree $garbagerepo;
+ my $garbagerepo = "$dgitrepos/${package}_garbage";
+ my $lfh =acquiretree($garbagerepo,1);
+ # 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 $!";
+ close $lfh;
}
sub onwardpush () {
@@ -391,6 +404,9 @@ sub parsetag () {
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";
@@ -520,6 +536,74 @@ sub checksuite () {
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/${package}_garbage";
+ acquiretree($garbagerepo,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};
@@ -545,6 +629,7 @@ sub checks () {
$version,$suite,$tagname,
join(",",@delberatelies));
+ checktagnoreplay();
checksuite();
# check that our ref is being fast-forwarded