Fix git-init failure with git ssh creds 🔑

In case of a private git resources that uses `ssh` keys, `git`
wouldn't find the correct `.ssh/known_hosts`. This only happens in
case of the user of the container is `root`.

We now treat use `root` as a special case. It should now work for any
user — being root or not.

Signed-off-by: Vincent Demeester <vdemeest@redhat.com>

pkg/credentials/gitcreds/ssh.go

@@ -28,6 +28,7 @@ import (
 
 	corev1 "k8s.io/api/core/v1"
 
+	"github.com/mitchellh/go-homedir"
 	"github.com/tektoncd/pipeline/pkg/credentials"
 )
 
@@ -76,7 +77,11 @@ func (dc *sshGitConfig) Set(value string) error {
 }
 
 func (dc *sshGitConfig) Write() error {
-	sshDir := filepath.Join(os.Getenv("HOME"), ".ssh")
+	homepath, err := homedir.Dir()
+	if err != nil {
+		return err
+	}
+	sshDir := filepath.Join(homepath, ".ssh")
 	if err := os.MkdirAll(sshDir, os.ModePerm); err != nil {
 		return err
 	}

pkg/git/git.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"os/user"
 	"strings"
 
 	homedir "github.com/mitchellh/go-homedir"
@@ -48,10 +49,19 @@ func Fetch(logger *zap.SugaredLogger, revision, path, url string) error {
 		return err
 	}
 	homeenv := os.Getenv("HOME")
-	if homeenv != "" && homeenv != homepath {
+	u, err := user.Current()
+	if err != nil {
+		return err
+	}
+	if u.Name == "root" {
+		if err := os.Symlink(homeenv+"/.ssh", "/root/.ssh"); err != nil {
+			// Only do a warning, in case we don't have a real home
+			// directory writable in our image
+			logger.Warnf("Unexpected error: creating symlink: %v", err)
+		}
+	} else if homeenv != "" && homeenv != homepath {
 		if _, err := os.Stat(homepath + "/.ssh"); os.IsNotExist(err) {
-			err = os.Symlink(homeenv+"/.ssh", homepath+"/.ssh")
-			if err != nil {
+			if err := os.Symlink(homeenv+"/.ssh", homepath+"/.ssh"); err != nil {
 				// Only do a warning, in case we don't have a real home
 				// directory writable in our image
 				logger.Warnf("Unexpected error: creating symlink: %v", err)