run: unset any HOME variable after USER ran

Running USER didn't reset HOME which had to be explicitly set.

Closes #1082

Signed-off-by: Yoan Blanc <yoan@dosimple.ch>

pkg/commands/run.go

@@ -77,6 +77,7 @@ func (r *RunCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.Bui
 		}
 		cmd.SysProcAttr.Credential = &syscall.Credential{Uid: uid, Gid: gid}
 	}
+
 	cmd.Env = addDefaultHOME(userStr, replacementEnvs)
 
 	if err := cmd.Start(); err != nil {

pkg/commands/user.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/GoogleContainerTools/kaniko/pkg/constants"
 	"github.com/GoogleContainerTools/kaniko/pkg/dockerfile"
 	"github.com/GoogleContainerTools/kaniko/pkg/util"
 	v1 "github.com/google/go-containerregistry/pkg/v1"
@@ -55,8 +56,19 @@ func (r *UserCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.Bu
 		}
 		userStr = userStr + ":" + groupStr
 	}
-
+	
 	config.User = userStr
+
+	// Remove any HOME environment variable previously set.
+	env := make([]string, 0, len(config.Env))
+	for _, v := range config.Env {
+		if strings.HasPrefix(v, constants.HOME+"=") {
+			continue
+		}
+		env = append(env, v)
+	}
+	config.Env = env
+
 	return nil
 }