From 26b037eb6711e77b1292def7a238b984c9432866 Mon Sep 17 00:00:00 2001
From: Simar <simar@linux.com>
Date: Mon, 12 Dec 2022 14:19:38 -0800
Subject: [PATCH] sumdb/dirhash: fix a panic when argument is not a directory

This patch fixes a case where a path to a non directory
can cause DirHash func to panic.

Fixes: https://github.com/golang/go/issues/57269

Signed-off-by: Simar <simar@linux.com>
---
 sumdb/dirhash/hash.go      | 10 +++++-
 sumdb/dirhash/hash_test.go | 68 +++++++++++++++++++++++---------------
 2 files changed, 51 insertions(+), 27 deletions(-)

diff --git a/sumdb/dirhash/hash.go b/sumdb/dirhash/hash.go
index ef5df6f..6c2672e 100644
--- a/sumdb/dirhash/hash.go
+++ b/sumdb/dirhash/hash.go
@@ -84,7 +84,15 @@ func HashDir(dir, prefix string, hash Hash) (string, error) {
 func DirFiles(dir, prefix string) ([]string, error) {
 	var files []string
 	dir = filepath.Clean(dir)
-	err := filepath.Walk(dir, func(file string, info os.FileInfo, err error) error {
+	dirInfo, err := os.Stat(dir)
+	if err != nil {
+		return nil, err
+	}
+	if !dirInfo.IsDir() {
+		return nil, fmt.Errorf("invalid directory path")
+	}
+
+	err = filepath.Walk(dir, func(file string, info os.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
diff --git a/sumdb/dirhash/hash_test.go b/sumdb/dirhash/hash_test.go
index ed463c1..5fd00be 100644
--- a/sumdb/dirhash/hash_test.go
+++ b/sumdb/dirhash/hash_test.go
@@ -105,31 +105,47 @@ func TestHashZip(t *testing.T) {
 }
 
 func TestDirFiles(t *testing.T) {
-	dir, err := ioutil.TempDir("", "dirfiles-test-")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.RemoveAll(dir)
-	if err := ioutil.WriteFile(filepath.Join(dir, "xyz"), []byte("data for xyz"), 0666); err != nil {
-		t.Fatal(err)
-	}
-	if err := ioutil.WriteFile(filepath.Join(dir, "abc"), []byte("data for abc"), 0666); err != nil {
-		t.Fatal(err)
-	}
-	if err := os.Mkdir(filepath.Join(dir, "subdir"), 0777); err != nil {
-		t.Fatal(err)
-	}
-	if err := ioutil.WriteFile(filepath.Join(dir, "subdir", "xyz"), []byte("data for subdir xyz"), 0666); err != nil {
-		t.Fatal(err)
-	}
-	prefix := "foo/bar@v2.3.4"
-	out, err := DirFiles(dir, prefix)
-	if err != nil {
-		t.Fatalf("DirFiles: %v", err)
-	}
-	for _, file := range out {
-		if !strings.HasPrefix(file, prefix) {
-			t.Errorf("Dir file = %s, want prefix %s", file, prefix)
+	t.Run("valid directory with files", func(t *testing.T) {
+		dir, err := ioutil.TempDir("", "dirfiles-test-")
+		if err != nil {
+			t.Fatal(err)
 		}
-	}
+		defer os.RemoveAll(dir)
+		if err := ioutil.WriteFile(filepath.Join(dir, "xyz"), []byte("data for xyz"), 0666); err != nil {
+			t.Fatal(err)
+		}
+		if err := ioutil.WriteFile(filepath.Join(dir, "abc"), []byte("data for abc"), 0666); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.Mkdir(filepath.Join(dir, "subdir"), 0777); err != nil {
+			t.Fatal(err)
+		}
+		if err := ioutil.WriteFile(filepath.Join(dir, "subdir", "xyz"), []byte("data for subdir xyz"), 0666); err != nil {
+			t.Fatal(err)
+		}
+		prefix := "foo/bar@v2.3.4"
+		out, err := DirFiles(dir, prefix)
+		if err != nil {
+			t.Fatalf("DirFiles: %v", err)
+		}
+		for _, file := range out {
+			if !strings.HasPrefix(file, prefix) {
+				t.Errorf("Dir file = %s, want prefix %s", file, prefix)
+			}
+		}
+	})
+
+	t.Run("invalid directory", func(t *testing.T) {
+		exePath, err := os.Executable()
+		if err != nil {
+			t.Fatalf("DirFiles: %v", err)
+		}
+		out, err := DirFiles(exePath, "")
+		if err == nil {
+			t.Errorf("DirFiles(...) = %s, want %s", err, "invalid directory path")
+		}
+		if len(out) > 0 {
+			t.Errorf("DirFiles(...) = unexpected files %s", out)
+		}
+	})
 }