[FAB-7428] Avoid reading links to dirs as files

Have getPemMaterialFromDir stat entries returned by ioutil.ReadDir to
resolve symlinks prior to checking if the entry is for a directory.

This avoids warnings that occur when treating links to directories as
files.

Change-Id: If4dd460bdce982da559f536435c7dd3bfb183889
Signed-off-by: Matthew Sykes <sykesmat@us.ibm.com>

Author: sykesm

msp/configbuilder.go

@@ -90,15 +90,21 @@ func getPemMaterialFromDir(dir string) ([][]byte, error) {
 	content := make([][]byte, 0)
 	files, err := ioutil.ReadDir(dir)
 	if err != nil {
-		return nil, errors.Wrapf(err, "could not read directory %s", err)
+		return nil, errors.Wrapf(err, "could not read directory %s", dir)
 	}
 
 	for _, f := range files {
+		fullName := filepath.Join(dir, f.Name())
+
+		f, err := os.Stat(fullName)
+		if err != nil {
+			mspLogger.Warningf("Failed to stat %s: %s", fullName, err)
+			continue
+		}
 		if f.IsDir() {
 			continue
 		}
 
-		fullName := filepath.Join(dir, string(filepath.Separator), f.Name())
 		mspLogger.Debugf("Inspecting file %s", fullName)
 
 		item, err := readPemFile(fullName)

msp/configbuilder_test.go

@@ -17,6 +17,9 @@ limitations under the License.
 package msp
 
 import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/hyperledger/fabric/core/config"
@@ -35,6 +38,41 @@ func TestGetLocalMspConfigFails(t *testing.T) {
 	assert.Error(t, err)
 }
 
+func TestGetPemMaterialFromDirWithFile(t *testing.T) {
+	tempFile, err := ioutil.TempFile("", "fabric-msp-test")
+	assert.NoError(t, err)
+	err = tempFile.Close()
+	assert.NoError(t, err)
+	defer os.Remove(tempFile.Name())
+
+	_, err = getPemMaterialFromDir(tempFile.Name())
+	assert.Error(t, err)
+}
+
+func TestGetPemMaterialFromDirWithSymlinks(t *testing.T) {
+	mspDir, err := config.GetDevMspDir()
+	assert.NoError(t, err)
+
+	tempDir, err := ioutil.TempDir("", "fabric-msp-test")
+	assert.NoError(t, err)
+	defer os.RemoveAll(tempDir)
+
+	dirSymlinkName := filepath.Join(tempDir, "..data")
+	err = os.Symlink(filepath.Join(mspDir, "signcerts"), dirSymlinkName)
+	assert.NoError(t, err)
+
+	fileSymlinkTarget := filepath.Join("..data", "peer.pem")
+	fileSymlinkName := filepath.Join(tempDir, "peer.pem")
+	err = os.Symlink(fileSymlinkTarget, fileSymlinkName)
+	assert.NoError(t, err)
+
+	pemdataSymlink, err := getPemMaterialFromDir(tempDir)
+	assert.NoError(t, err)
+	expected, err := getPemMaterialFromDir(filepath.Join(mspDir, "signcerts"))
+	assert.NoError(t, err)
+	assert.Equal(t, pemdataSymlink, expected)
+}
+
 func TestReadFileUtils(t *testing.T) {
 	// test that reading a file with an empty path doesn't crash
 	_, err := readPemFile("")