Merge branch 'CNT-3998/cdi-accept-visible-devices-when-privileged' into 'main'

Honor accept-nvidia-visible-devices-envvar-when-unprivileged setting in CDI mode

See merge request nvidia/container-toolkit/container-toolkit!331

cmd/nvidia-container-runtime-hook/container_config.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	"github.com/NVIDIA/nvidia-container-toolkit/internal/config/image"
+	"github.com/opencontainers/runtime-spec/specs-go"
 	"golang.org/x/mod/semver"
 )
 
@@ -130,7 +131,7 @@ func isPrivileged(s *Spec) bool {
 	}
 
 	var caps []string
-	// If v1.1.0-rc1 <= OCI version < v1.0.0-rc5 parse s.Process.Capabilities as:
+	// If v1.0.0-rc1 <= OCI version < v1.0.0-rc5 parse s.Process.Capabilities as:
 	// github.com/opencontainers/runtime-spec/blob/v1.0.0-rc1/specs-go/config.go#L30-L54
 	rc1cmp := semver.Compare("v"+*s.Version, "v1.0.0-rc1")
 	rc5cmp := semver.Compare("v"+*s.Version, "v1.0.0-rc5")
@@ -139,28 +140,31 @@ func isPrivileged(s *Spec) bool {
 		if err != nil {
 			log.Panicln("could not decode Process.Capabilities in OCI spec:", err)
 		}
-		// Otherwise, parse s.Process.Capabilities as:
-		// github.com/opencontainers/runtime-spec/blob/v1.0.0/specs-go/config.go#L30-L54
-	} else {
-		var lc LinuxCapabilities
-		err := json.Unmarshal(*s.Process.Capabilities, &lc)
-		if err != nil {
-			log.Panicln("could not decode Process.Capabilities in OCI spec:", err)
+		for _, c := range caps {
+			if c == capSysAdmin {
+				return true
+			}
 		}
-		// We only make sure that the bounding capabibility set has
-		// CAP_SYS_ADMIN. This allows us to make sure that the container was
-		// actually started as '--privileged', but also allow non-root users to
-		// access the privileged NVIDIA capabilities.
-		caps = lc.Bounding
+		return false
 	}
 
-	for _, c := range caps {
-		if c == capSysAdmin {
-			return true
-		}
+	// Otherwise, parse s.Process.Capabilities as:
+	// github.com/opencontainers/runtime-spec/blob/v1.0.0/specs-go/config.go#L30-L54
+	process := specs.Process{
+		Env: s.Process.Env,
 	}
 
-	return false
+	err := json.Unmarshal(*s.Process.Capabilities, &process.Capabilities)
+	if err != nil {
+		log.Panicln("could not decode Process.Capabilities in OCI spec:", err)
+	}
+
+	fullSpec := specs.Spec{
+		Version: *s.Version,
+		Process: &process,
+	}
+
+	return image.IsPrivileged(&fullSpec)
 }
 
 func getDevicesFromEnvvar(image image.CUDA, swarmResourceEnvvars []string) *string {

internal/config/config.go

@@ -45,6 +45,8 @@ var (
 // Config represents the contents of the config.toml file for the NVIDIA Container Toolkit
 // Note: This is currently duplicated by the HookConfig in cmd/nvidia-container-toolkit/hook_config.go
 type Config struct {
+	AcceptEnvvarUnprivileged bool `toml:"accept-nvidia-visible-devices-envvar-when-unprivileged"`
+
 	NVIDIAContainerCLIConfig     ContainerCLIConfig `toml:"nvidia-container-cli"`
 	NVIDIACTKConfig              CTKConfig          `toml:"nvidia-ctk"`
 	NVIDIAContainerRuntimeConfig RuntimeConfig      `toml:"nvidia-container-runtime"`
@@ -91,6 +93,8 @@ func getConfigFrom(toml *toml.Tree) (*Config, error) {
 		return cfg, nil
 	}
 
+	cfg.AcceptEnvvarUnprivileged = toml.GetDefault("accept-nvidia-visible-devices-envvar-when-unprivileged", cfg.AcceptEnvvarUnprivileged).(bool)
+
 	cfg.NVIDIAContainerCLIConfig = *getContainerCLIConfigFrom(toml)
 	cfg.NVIDIACTKConfig = *getCTKConfigFrom(toml)
 	runtimeConfig, err := getRuntimeConfigFrom(toml)
@@ -105,6 +109,7 @@ func getConfigFrom(toml *toml.Tree) (*Config, error) {
 // getDefaultConfig defines the default values for the config
 func getDefaultConfig() *Config {
 	c := Config{
+		AcceptEnvvarUnprivileged:     true,
 		NVIDIAContainerCLIConfig:     *getDefaultContainerCLIConfig(),
 		NVIDIACTKConfig:              *getDefaultCTKConfig(),
 		NVIDIAContainerRuntimeConfig: *GetDefaultRuntimeConfig(),

internal/config/config_test.go

@@ -57,6 +57,7 @@ func TestGetConfig(t *testing.T) {
 		{
 			description: "empty config is default",
 			expectedConfig: &Config{
+				AcceptEnvvarUnprivileged: true,
 				NVIDIAContainerCLIConfig: ContainerCLIConfig{
 					Root: "",
 				},
@@ -82,6 +83,7 @@ func TestGetConfig(t *testing.T) {
 		{
 			description: "config options set inline",
 			contents: []string{
+				"accept-nvidia-visible-devices-envvar-when-unprivileged = false",
 				"nvidia-container-cli.root = \"/bar/baz\"",
 				"nvidia-container-runtime.debug = \"/foo/bar\"",
 				"nvidia-container-runtime.experimental = true",
@@ -94,6 +96,7 @@ func TestGetConfig(t *testing.T) {
 				"nvidia-ctk.path = \"/foo/bar/nvidia-ctk\"",
 			},
 			expectedConfig: &Config{
+				AcceptEnvvarUnprivileged: false,
 				NVIDIAContainerCLIConfig: ContainerCLIConfig{
 					Root: "/bar/baz",
 				},
@@ -119,6 +122,7 @@ func TestGetConfig(t *testing.T) {
 		{
 			description: "config options set in section",
 			contents: []string{
+				"accept-nvidia-visible-devices-envvar-when-unprivileged = false",
 				"[nvidia-container-cli]",
 				"root = \"/bar/baz\"",
 				"[nvidia-container-runtime]",
@@ -136,6 +140,7 @@ func TestGetConfig(t *testing.T) {
 				"path = \"/foo/bar/nvidia-ctk\"",
 			},
 			expectedConfig: &Config{
+				AcceptEnvvarUnprivileged: false,
 				NVIDIAContainerCLIConfig: ContainerCLIConfig{
 					Root: "/bar/baz",
 				},

internal/config/image/privileged.go

@@ -0,0 +1,43 @@
+/**
+# Copyright (c) NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+**/
+
+package image
+
+import (
+	"github.com/opencontainers/runtime-spec/specs-go"
+)
+
+const (
+	capSysAdmin = "CAP_SYS_ADMIN"
+)
+
+// IsPrivileged returns true if the container is a privileged container.
+func IsPrivileged(s *specs.Spec) bool {
+	if s.Process.Capabilities == nil {
+		return false
+	}
+
+	// We only make sure that the bounding capabibility set has
+	// CAP_SYS_ADMIN. This allows us to make sure that the container was
+	// actually started as '--privileged', but also allow non-root users to
+	// access the privileged NVIDIA capabilities.
+	for _, c := range s.Process.Capabilities.Bounding {
+		if c == capSysAdmin {
+			return true
+		}
+	}
+	return false
+}

internal/modifier/cdi.go

@@ -37,7 +37,7 @@ type cdiModifier struct {
 // CDI specifications available on the system. The NVIDIA_VISIBLE_DEVICES enviroment variable is
 // used to select the devices to include.
 func NewCDIModifier(logger *logrus.Logger, cfg *config.Config, ociSpec oci.Spec) (oci.SpecModifier, error) {
-	devices, err := getDevicesFromSpec(logger, ociSpec, cfg.NVIDIAContainerRuntimeConfig.Modes.CDI.DefaultKind)
+	devices, err := getDevicesFromSpec(logger, ociSpec, cfg)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get required devices from OCI specification: %v", err)
 	}
@@ -61,7 +61,7 @@ func NewCDIModifier(logger *logrus.Logger, cfg *config.Config, ociSpec oci.Spec)
 	return m, nil
 }
 
-func getDevicesFromSpec(logger *logrus.Logger, ociSpec oci.Spec, defaultKind string) ([]string, error) {
+func getDevicesFromSpec(logger *logrus.Logger, ociSpec oci.Spec, cfg *config.Config) ([]string, error) {
 	rawSpec, err := ociSpec.Load()
 	if err != nil {
 		return nil, fmt.Errorf("failed to load OCI spec: %v", err)
@@ -75,17 +75,17 @@ func getDevicesFromSpec(logger *logrus.Logger, ociSpec oci.Spec, defaultKind str
 		return annotationDevices, nil
 	}
 
-	image, err := image.NewCUDAImageFromSpec(rawSpec)
+	container, err := image.NewCUDAImageFromSpec(rawSpec)
 	if err != nil {
 		return nil, err
 	}
-	envDevices := image.DevicesFromEnvvars(visibleDevicesEnvvar)
+	envDevices := container.DevicesFromEnvvars(visibleDevicesEnvvar)
 
 	var devices []string
 	seen := make(map[string]bool)
 	for _, name := range envDevices.List() {
 		if !cdi.IsQualifiedName(name) {
-			name = fmt.Sprintf("%s=%s", defaultKind, name)
+			name = fmt.Sprintf("%s=%s", cfg.NVIDIAContainerRuntimeConfig.Modes.CDI.DefaultKind, name)
 		}
 		if seen[name] {
 			logger.Debugf("Ignoring duplicate device %q", name)
@@ -94,6 +94,16 @@ func getDevicesFromSpec(logger *logrus.Logger, ociSpec oci.Spec, defaultKind str
 		devices = append(devices, name)
 	}
 
+	if len(devices) == 0 {
+		return nil, nil
+	}
+
+	if cfg.AcceptEnvvarUnprivileged || image.IsPrivileged(rawSpec) {
+		return devices, nil
+	}
+
+	logger.Warningf("Ignoring devices specified in NVIDIA_VISIBLE_DEVICES: %v", devices)
+
 	return devices, nil
 }