syscall: move check of unprivileged_userns_clone to whoamiCmd

This is basic validation and should be performed early

Fixes #12412

Change-Id: I903f7eeafdc22376704985a53d649698cf9d8ef4
Reviewed-on: https://go-review.googlesource.com/14110
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/syscall/exec_linux_test.go b/src/syscall/exec_linux_test.go
index 8c8773629d1ca9b002ac23db31e71ec25f4a93be..bbfd6d03df26b782fd878f495d06bde6617930f4 100644 (file)
--- a/src/syscall/exec_linux_test.go
+++ b/src/syscall/exec_linux_test.go
@@ -24,6 +24,13 @@ func whoamiCmd(t *testing.T, uid, gid int, setgroups bool) *exec.Cmd {
                }
                t.Fatalf("Failed to stat /proc/self/ns/user: %v", err)
        }
+       // On some systems, there is a sysctl setting.
+       if os.Getuid() != 0 {
+               data, errRead := ioutil.ReadFile("/proc/sys/kernel/unprivileged_userns_clone")
+               if errRead == nil && data[0] == '0' {
+                       t.Skip("kernel prohibits user namespace in unprivileged process")
+               }
+       }
        cmd := exec.Command("whoami")
        cmd.SysProcAttr = &syscall.SysProcAttr{
                Cloneflags: syscall.CLONE_NEWUSER,
@@ -42,14 +49,6 @@ func testNEWUSERRemap(t *testing.T, uid, gid int, setgroups bool) {
        cmd := whoamiCmd(t, uid, gid, setgroups)
        out, err := cmd.CombinedOutput()
        if err != nil {
-               // On some systems, there is a sysctl setting.
-               if os.IsPermission(err) && os.Getuid() != 0 {
-                       data, errRead := ioutil.ReadFile("/proc/sys/kernel/unprivileged_userns_clone")
-                       if errRead == nil && data[0] == '0' {
-                               t.Skip("kernel prohibits user namespace in unprivileged process")
-                       }
-               }
-
                t.Fatalf("Cmd failed with err %v, output: %s", err, out)
        }
        sout := strings.TrimSpace(string(out))