prevent access to repos which are in the process of bring migrated

Björn Kautler pointed out that, when a repo is being migrated into
gitolite as per the documentation [1], there is a gap between the actual
move of the repo and the rest of the process where a user can gain read
or write access to the repo, which he would *not* have had after the
completion of the process.

My first thought was to document this, and advise people to use the
'writable' command to disable writes, but there is nothing as simple and
painless to prevent reads.  (On the plus side, this kind of racy read
access can only happen if the conf is using the "deny-rules" option to
restrict reads; without that, it makes no difference -- i.e., he gets no
access that he would not have got later anyway).

But eventually I realised that documentation was frustrating, for
various reasons, and that at least in this case there is a way to fix it
in the code -- just block all access to a repo that is in
~/repositories, but which does not yet have the update hook setup
correctly.  Plus, the code does not impact anything else, and is
basically just an extra check.

[1]: http://gitolite.com/gitolite/basic-admin/index.html#appendix-1-bringing-existing-repos-into-gitolite

2 files changed, 25 insertions, 2 deletions

diff --git a/src/gitolite-shell b/src/gitolite-shell
index 072e0ff..6c4c462 100755
--- a/src/gitolite-shell
+++ b/src/gitolite-shell
@@ -113,6 +113,13 @@ sub main {
     $ENV{GL_REPO} = $repo;
     my $aa = ( $verb =~ 'upload' ? 'R' : 'W' );
 
+    # catch rare race when moving repos into gitolite control
+    _die "$aa any $repo $user DENIED by fallthru" .
+            "\n(or you mis-spelled the reponame)"
+        unless update_hook_present($repo);
+    # this error message is exactly the same as that from elsewhere in the
+    # code, for the usual reasons (avoid leaking information)
+
     # set up env vars from options set for this repo
     env_options($repo);
 
diff --git a/src/lib/Gitolite/Common.pm b/src/lib/Gitolite/Common.pm
index 7a52f4b..3f47b37 100644
--- a/src/lib/Gitolite/Common.pm
+++ b/src/lib/Gitolite/Common.pm
@@ -19,6 +19,8 @@ package Gitolite::Common;
 
           ssh_fingerprint_file
           ssh_fingerprint_line
+
+          update_hook_present
 );
 #>>>
 use Exporter 'import';
@@ -235,14 +237,28 @@ sub cleanup_conf_line {
             chomp($repo);
             $repo =~ s/\.git$//;
             $repo =~ s(^\./)();
-            push @phy_repos, $repo unless $repo =~ m(/$);
-                # tolerate bare repos within ~/repositories but silently ignore them
+            next if $repo =~ m(/$);
+                # tolerate non-bare repos within ~/repositories but silently ignore them
+            next unless update_hook_present($repo);
+                # ignore repos that don't yet have the update hook
+            push @phy_repos, $repo;
         }
         trace( 3, scalar(@phy_repos) . " physical repos found" );
         return sort_u( \@phy_repos );
     }
 }
 
+sub update_hook_present {
+    my $repo = shift;
+
+    return 1 unless -d "$ENV{GL_REPO_BASE}/$repo.git";  # non-existent repo is fine
+
+    my $x = readlink("$ENV{GL_REPO_BASE}/$repo.git/hooks/update");
+    return 1 if $x and $x eq "$ENV{GL_ADMIN_BASE}/hooks/common/update";
+
+    return 0;
+}
+
 # generate a timestamp
 sub gen_ts {
     my ( $s, $min, $h, $d, $m, $y ) = (localtime)[ 0 .. 5 ];