Add GMSA Credential Spec passing

Signed-off-by: Daniel Canter <dcanter@microsoft.com>

pkg/containerd/opts/spec_windows.go

@@ -188,3 +188,15 @@ func WithWindowsDefaultSandboxShares(ctx context.Context, client oci.Client, c *
 	s.Windows.Resources.CPU.Shares = &i
 	return nil
 }
+
+// WithWindowsCredentialSpec assigns `credentialSpec` to the
+// `runtime.Spec.Windows.CredentialSpec` field.
+func WithWindowsCredentialSpec(credentialSpec string) oci.SpecOpts {
+	return func(ctx context.Context, client oci.Client, c *containers.Container, s *runtimespec.Spec) error {
+		if s.Windows == nil {
+			s.Windows = &runtimespec.Windows{}
+		}
+		s.Windows.CredentialSpec = credentialSpec
+		return nil
+	}
+}

pkg/server/container_create_windows.go

@@ -68,13 +68,30 @@ func (c *criService) containerSpec(id string, sandboxID string, sandboxPid uint3
 
 	specOpts = append(specOpts, customopts.WithWindowsMounts(c.os, config, extraMounts))
 
-	specOpts = append(specOpts, customopts.WithWindowsResources(config.GetWindows().GetResources()))
+	// Start with the image config user and override below if RunAsUsername is not "".
+	username := imageConfig.User
 
-	username := config.GetWindows().GetSecurityContext().GetRunAsUsername()
-	if username != "" {
-		specOpts = append(specOpts, oci.WithUser(username))
+	windowsConfig := config.GetWindows()
+	if windowsConfig != nil {
+		specOpts = append(specOpts, customopts.WithWindowsResources(windowsConfig.GetResources()))
+		securityCtx := windowsConfig.GetSecurityContext()
+		if securityCtx != nil {
+			runAsUser := securityCtx.GetRunAsUsername()
+			if runAsUser != "" {
+				username = runAsUser
+			}
+			cs := securityCtx.GetCredentialSpec()
+			if cs != "" {
+				specOpts = append(specOpts, customopts.WithWindowsCredentialSpec(cs))
+			}
+		}
 	}
-	// TODO(windows): Add CredentialSpec support.
+
+	// There really isn't a good Windows way to verify that the username is available in the
+	// image as early as here like there is for Linux. Later on in the stack hcsshim
+	// will handle the behavior of erroring out if the user isn't available in the image
+	// when trying to run the init process.
+	specOpts = append(specOpts, oci.WithUser(username))
 
 	for pKey, pValue := range getPassthroughAnnotations(sandboxConfig.Annotations,
 		ociRuntime.PodAnnotations) {

pkg/server/container_create_windows_test.go

@@ -72,7 +72,8 @@ func getCreateContainerTestData() (*runtime.ContainerConfig, *runtime.PodSandbox
 				MemoryLimitInBytes: 400,
 			},
 			SecurityContext: &runtime.WindowsContainerSecurityContext{
-				RunAsUsername: "test-user",
+				RunAsUsername:  "test-user",
+				CredentialSpec: "{\"test\": \"spec\"}",
 			},
 		},
 	}
@@ -91,6 +92,7 @@ func getCreateContainerTestData() (*runtime.ContainerConfig, *runtime.PodSandbox
 		Entrypoint: []string{"/entrypoint"},
 		Cmd:        []string{"cmd"},
 		WorkingDir: "/workspace",
+		User:       "ContainerUser",
 	}
 	specCheck := func(t *testing.T, id string, sandboxID string, sandboxPid uint32, spec *runtimespec.Spec) {
 		assert.Nil(t, spec.Root)
@@ -111,9 +113,13 @@ func getCreateContainerTestData() (*runtime.ContainerConfig, *runtime.PodSandbox
 		assert.EqualValues(t, *spec.Windows.Resources.CPU.Maximum, 300)
 		assert.EqualValues(t, *spec.Windows.Resources.Memory.Limit, 400)
 
+		// Also checks if override of the image configs user is behaving.
 		t.Logf("Check username")
 		assert.Contains(t, spec.Process.User.Username, "test-user")
 
+		t.Logf("Check credential spec")
+		assert.Contains(t, spec.Windows.CredentialSpec, "{\"test\": \"spec\"}")
+
 		t.Logf("Check PodSandbox annotations")
 		assert.Contains(t, spec.Annotations, annotations.SandboxID)
 		assert.EqualValues(t, spec.Annotations[annotations.SandboxID], sandboxID)