From 5df3c3e3f6b1b2d6f20549b45dcb01f1865e10d8 Mon Sep 17 00:00:00 2001
From: Zethan <zetHannes@outlook.com>
Date: Wed, 9 Mar 2022 21:52:37 +0100
Subject: [PATCH] Add plugin validity checks to isPlugin

Signed-off-by: Zethan <zetHannes@outlook.com>
---
 pkg/plugin/installer/installer.go                | 16 +++++++++++++---
 pkg/plugin/installer/installer_test.go           | 12 ++++++++++++
 .../plugdir/bad/empty-config/plugin.yaml         |  1 +
 .../testdata/plugdir/bad/invalid/plugin.yaml     |  3 +++
 4 files changed, 29 insertions(+), 3 deletions(-)
 create mode 100644 pkg/plugin/testdata/plugdir/bad/invalid/plugin.yaml

diff --git a/pkg/plugin/installer/installer.go b/pkg/plugin/installer/installer.go
index 6f01494e5..ede90ab78 100644
--- a/pkg/plugin/installer/installer.go
+++ b/pkg/plugin/installer/installer.go
@@ -17,6 +17,7 @@ package installer
 
 import (
 	"fmt"
+	"io/ioutil"
 	"log"
 	"net/http"
 	"os"
@@ -26,6 +27,7 @@ import (
 	"github.com/pkg/errors"
 
 	"helm.sh/helm/v3/pkg/plugin"
+	"sigs.k8s.io/yaml"
 )
 
 // ErrMissingMetadata indicates that plugin.yaml is missing.
@@ -120,10 +122,18 @@ func isRemoteHTTPArchive(source string) bool {
 	return false
 }
 
-// isPlugin checks if the directory contains a plugin.yaml file.
+// isPlugin checks if the directory contains a valid plugin.yaml file
 func isPlugin(dirname string) bool {
-	_, err := os.Stat(filepath.Join(dirname, plugin.PluginFileName))
-	return err == nil
+	fpath := filepath.Join(dirname, plugin.PluginFileName)
+	if _, err := os.Stat(fpath); err != nil {
+		return false
+	}
+	plug := &plugin.Plugin{Dir: dirname}
+	data, _ := ioutil.ReadFile(fpath)
+	if err := yaml.UnmarshalStrict(data, &plug.Metadata); err != nil || plug.Metadata == nil {
+		return false
+	}
+	return true
 }
 
 var logger = log.New(os.Stderr, "[debug] ", log.Lshortfile)
diff --git a/pkg/plugin/installer/installer_test.go b/pkg/plugin/installer/installer_test.go
index a11464924..235ba63ef 100644
--- a/pkg/plugin/installer/installer_test.go
+++ b/pkg/plugin/installer/installer_test.go
@@ -38,3 +38,15 @@ func TestIsRemoteHTTPArchive(t *testing.T) {
 		t.Error("Expected media type match to fail")
 	}
 }
+
+func TestIsPlugin(t *testing.T) {
+	if isPlugin("../testdata/plugdir/bad/empty-config") {
+		t.Errorf("Expected empty plugin file not to be considered a plugin")
+	}
+	if !isPlugin("../testdata/plugdir/good/echo") {
+		t.Errorf("Expected valid plugin file to be considered a plugin")
+	}
+	if isPlugin("../testdata/plugdir/bad/invalid") {
+		t.Errorf("Expected invalid plugin not to be considered a plugin")
+	}
+}
diff --git a/pkg/plugin/testdata/plugdir/bad/empty-config/plugin.yaml b/pkg/plugin/testdata/plugdir/bad/empty-config/plugin.yaml
index e69de29bb..0519ecba6 100644
--- a/pkg/plugin/testdata/plugdir/bad/empty-config/plugin.yaml
+++ b/pkg/plugin/testdata/plugdir/bad/empty-config/plugin.yaml
@@ -0,0 +1 @@
+ 
\ No newline at end of file
diff --git a/pkg/plugin/testdata/plugdir/bad/invalid/plugin.yaml b/pkg/plugin/testdata/plugdir/bad/invalid/plugin.yaml
new file mode 100644
index 000000000..41a96812b
--- /dev/null
+++ b/pkg/plugin/testdata/plugdir/bad/invalid/plugin.yaml
@@ -0,0 +1,3 @@
+name: "invalid-test"
+version: "1.2.3"
+usa