buildah: force umask 022

an umask more restrictive can break some images.

Closes: containers#1305

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

cmd/buildah/common.go

@@ -3,6 +3,7 @@ package main
 import (
  "context"
  "os"
+ "syscall"
  "time"
 
  "github.com/containers/buildah"
@@ -13,6 +14,7 @@ import (
  "github.com/containers/storage"
  "github.com/opencontainers/go-digest"
  "github.com/pkg/errors"
+ "github.com/sirupsen/logrus"
  "github.com/spf13/cobra"
  "github.com/spf13/pflag"
 )
@@ -88,6 +90,11 @@ func getStore(c *cobra.Command) (storage.Store, error) {
  options.GIDMap = gidmap
  }
 
+ oldUmask := syscall.Umask(0022)
+ if (oldUmask & ^0022) != 0 {
+ logrus.Debugf("umask value too restrictive. Forcing it to 022")
+ }
+
  store, err := storage.GetStore(options)
  if store != nil {
  is.Transport.SetStore(store)