Enhanced GitHub webhooks: support for secrets and for more events

doc/manual/src/webhooks.md

@@ -1,13 +1,40 @@
 # Webhooks
 
-Hydra can be notified by github's webhook to trigger a new evaluation when a
-jobset has a github repo in its input.
-To set up a github webhook go to `https://github.com/<yourhandle>/<yourrepo>/settings` and in the `Webhooks` tab
+## GitHub
+Hydra can be notified by GitHub's webhook to trigger a new evaluation when a
+jobset has a GitHub repo in its input.
+
+GitHub's webhook can be triggered on [various events](https://docs.github.com/en/developers/webhooks-and-events/webhooks/webhook-events-and-payloads). Hydra recognizes the following events.
+
+ - [`push`](https://docs.github.com/en/developers/webhooks-and-events/webhooks/webhook-events-and-payloads#push): triggers a new evaluation for every jobset that have the GitHub repository as a "Git Checkout" input.
+ - [`create`](https://docs.github.com/en/developers/webhooks-and-events/webhooks/webhook-events-and-payloads#create) and [`delete`](https://docs.github.com/en/developers/webhooks-and-events/webhooks/webhook-events-and-payloads#deleta): triggers a new evaluation for every jobset that have the GitHub repository as a "github_refs" input.
+ - [`pull_request`](https://docs.github.com/en/developers/webhooks-and-events/webhooks/webhook-events-and-payloads#pull_request): triggers a new evaluation for every jobset that have the GitHub repository as a "githubpulls" input.
+
+### Guide
+
+To set up a GitHub webhook go to `https://github.com/<yourhandle>/<yourrepo>/settings` and in the `Webhooks` tab
 click on `Add webhook`.
 
-- In `Payload URL` fill in `https://<your-hydra-domain>/api/push-github`.
+- In `Payload URL` fill in `https://<your-hydra-domain>/api/webhook-github`.
 - In `Content type` switch to `application/json`.
-- The `Secret` field can stay empty.
-- For `Which events would you like to trigger this webhook?` keep the default option for events on `Just the push event.`.
+- The `Secret` field can stay empty (see below to configure a secret).
+- For `Which events would you like to trigger this webhook?` either keep the default option, or select the ones you are interested in (see above for the supported events).
 
 Then add the hook with `Add webhook`.
+
+### Securing GitHub's webhooks
+Secrets for webhooks can be configured by adding `github_webhook` keys in your Hydra configuration.
+Each `github_webhook` provides a secret (`secret`, a string) for a certain range of repository name (`repo`, a regex) and repository owner (`owner`, a regex).
+
+For instance below we declare one secret, `foo`, for the repositories whose owner is `someone` or `someother` and is named `somerepo`.
+
+**IMPORTANT**: note that secrets should **never** be included directly in your `hydra.conf`, otherwise they will be exposed in plain text in the store. Instead, use includes [as described here](./configuration.html#including-files).
+
+```xml
+<github_webhook>
+  owner = (someone|someother)
+  repo = somerepo
+  secret = foo
+</github_webhook>
+```
+

src/lib/Hydra/Controller/API.pm

@@ -9,9 +9,13 @@ use Hydra::Helper::CatalystUtils;
 use Hydra::Controller::Project;
 use JSON::MaybeXS;
 use DateTime;
-use Digest::SHA qw(sha256_hex);
+use Digest::SHA qw(sha256 sha256_hex);
+use Digest::HMAC qw(hmac_hex);
+use String::Compare::ConstantTime;
+use File::Slurper qw(read_text);
 use Text::Diff;
 use IPC::Run qw(run);
+use List::Util 'first';
 
 
 sub api : Chained('/') PathPart('api') CaptureArgs(0) {
@@ -267,24 +271,76 @@ sub push : Chained('api') PathPart('push') Args(0) {
     );
 }
 
-sub push_github : Chained('api') PathPart('push-github') Args(0) {
+sub webhook_github : Chained('api') PathPart('webhook-github') Args(0) {
     my ($self, $c) = @_;
 
     $c->{stash}->{json}->{jobsetsTriggered} = [];
 
     my $in = $c->request->{data};
-    my $owner = $in->{repository}->{owner}->{name} or die;
-    my $repo = $in->{repository}->{name} or die;
-    print STDERR "got push from GitHub repository $owner/$repo\n";
-
-    triggerJobset($self, $c, $_, 0) foreach $c->model('DB::Jobsets')->search(
-        { 'project.enabled' => 1, 'me.enabled' => 1 },
-        { join => 'project'
-        , where => \ [ 'me.flake like ? or exists (select 1 from JobsetInputAlts where project = me.project and jobset = me.name and value like ?)', [ 'flake', "%github%$owner/$repo%"], [ 'value', "%github.com%$owner/$repo%" ] ]
-        });
+
+    # every GitHub webhook payload has the `repository` key and a `X-GitHub-Event` header
+    my $event = $c->req->header('X-GitHub-Event')        or die;
+    my $owner = (   $in->{repository}->{owner}->{name}
+		 // $in->{repository}->{owner}->{login}) or die;
+    my $repo  = $in->{repository}->{name}                or die;
+
+    print STDERR "got event '$event' from GitHub repository $owner/$repo\n";
+
+    { # Verify X-Hub-Signature-256 if secret was defined in config
+	my $cfg = $c->config->{github_webhook};
+	my @config = defined $cfg ? ref $cfg eq "ARRAY" ? @$cfg : ($cfg) : ();	
+	my $rule = first { $owner =~ /^$_->{owner}$/ && $repo =~ /^$_->{repo}$/ } @config;
+
+	if (defined $rule) {
+	    my $sig = $c->req->header('X-Hub-Signature-256');
+	    die "X-Hub-Signature-256 is missing, but a secret was defined for GitHub repository $owner/$repo"
+		unless defined $sig;
+	    my $body = read_text($c->req->body) or die;
+	    my $secret = $rule->{secret}        or die;
+	    my $digest = hmac_hex($body, $secret, \&sha256);
+	    die "Request body digest (${digest}) did not match X-Hub-Signature-256 (${sig})"
+		unless String::Compare::ConstantTime::equals($sig, "sha256=$digest");
+	} else {
+	    print STDERR "no secret given for webhook comming from GitHub repository $owner/$repo";
+	}
+    }
+
+    # `jobsetsOfInputs type value` finds the jobsets that have an input of type `type` and of value LIKE `value`
+    my $jobsetsOfInputs = sub {
+	my ($type, $value) = @_;
+	$c->model('DB::Jobsets')->search(
+	    { 'jobsetinputs.type' => $type, 'project.enabled' => 1, 'me.enabled' => 1 },
+	    { join => ['project', {'jobsetinputs' => 'jobsetinputalts'}],
+	      where => \ [ ' LOWER( jobsetinputalts.value ) LIKE LOWER ( ? ) ', [ 'value', $value] ]
+	    })
+    };
+
+    # Different SQL queries according the kind of `$event` we are dealing with
+    my $actions = {
+        create       => sub {$jobsetsOfInputs->('github_refs', "$owner $repo %")},
+        delete       => sub {$jobsetsOfInputs->('github_refs', "$owner $repo %")},
+	pull_request => sub {$jobsetsOfInputs->('githubpulls', "$owner $repo")},
+	push => sub {
+	    $c->model('DB::Jobsets')->search(
+		{ 'project.enabled' => 1, 'me.enabled' => 1 },
+		{ join => 'project', where => \ [
+		      'me.flake like ? or exists (select 1 from JobsetInputAlts where project = me.project and jobset = me.name and value like ?)',
+		      [ 'flake', "%github%$owner/$repo%"],
+		      [ 'value', "%github.com%$owner/$repo%" ]
+		   ] })
+	}
+    };
+
+    triggerJobset($self, $c, $_, 0) foreach ($actions->{$event} // sub {
+	die "Cannot handle GitHub event [$event]";
+    })->();
+
     $c->response->body("");
 }
 
-
+sub push_github : Chained('api') PathPart('push-github') Args(0) {
+    print STDERR 'The endpoint [/api/push_github] is deprecated in favor of [/api/webhook_github]';
+    webhook_github @_
+}
 
 1;

src/lib/Hydra/Controller/Root.pm

@@ -32,6 +32,7 @@ sub noLoginNeeded {
 
   return $whitelisted ||
          $c->request->path eq "api/push-github" ||
+         $c->request->path eq "api/webhook-github" ||
          $c->request->path eq "google-login" ||
          $c->request->path eq "github-redirect" ||
          $c->request->path eq "github-login" ||
@@ -77,7 +78,9 @@ sub begin :Private {
     $_->supportedInputTypes($c->stash->{inputTypes}) foreach @{$c->hydra_plugins};
 
     # XSRF protection: require POST requests to have the same origin.
-    if ($c->req->method eq "POST" && $c->req->path ne "api/push-github") {
+    if ($c->req->method eq "POST" && (
+	    $c->req->path ne "api/push-github" && $c->req->path ne "api/webhook-github"
+	)) {
         my $referer = $c->req->header('Referer');
         $referer //= $c->req->header('Origin');
         my $base = $c->req->base;

t/Hydra/Controller/API/checks.t

@@ -169,6 +169,7 @@ subtest "/api/push-github" => sub {
 
         my $req = POST '/api/push-github',
             "Content-Type" => "application/json",
+	    "X-GitHub-Event" => "push",
             "Content" => encode_json({
                 repository => {
                     owner => {
@@ -195,6 +196,7 @@ subtest "/api/push-github" => sub {
 
         my $req = POST '/api/push-github',
             "Content-Type" => "application/json",
+	    "X-GitHub-Event" => "push",
             "Content" => encode_json({
                 repository => {
                     owner => {