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moby--moby/daemon/config/config.go
Brian Goff dfcb3e17ae Allow containerd shim refs in default-runtime
Since runtimes can now just be containerd shims, we need to check if the
reference is possibly a containerd shim.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit e6ee27a541)
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2022-08-18 18:51:23 +00:00

702 lines
26 KiB
Go

package config // import "github.com/docker/docker/daemon/config"
import (
"bytes"
"encoding/json"
"fmt"
"net"
"net/url"
"os"
"path/filepath"
"strings"
"sync"
"github.com/containerd/containerd/runtime/v2/shim"
"github.com/docker/docker/opts"
"github.com/docker/docker/pkg/authorization"
"github.com/docker/docker/registry"
"github.com/imdario/mergo"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"github.com/spf13/pflag"
)
const (
// DefaultMaxConcurrentDownloads is the default value for
// maximum number of downloads that
// may take place at a time for each pull.
DefaultMaxConcurrentDownloads = 3
// DefaultMaxConcurrentUploads is the default value for
// maximum number of uploads that
// may take place at a time for each push.
DefaultMaxConcurrentUploads = 5
// DefaultDownloadAttempts is the default value for
// maximum number of attempts that
// may take place at a time for each pull when the connection is lost.
DefaultDownloadAttempts = 5
// DefaultShmSize is the default value for container's shm size (64 MiB)
DefaultShmSize int64 = 64 * 1024 * 1024
// DefaultNetworkMtu is the default value for network MTU
DefaultNetworkMtu = 1500
// DisableNetworkBridge is the default value of the option to disable network bridge
DisableNetworkBridge = "none"
// DefaultShutdownTimeout is the default shutdown timeout (in seconds) for
// the daemon for containers to stop when it is shutting down.
DefaultShutdownTimeout = 15
// DefaultInitBinary is the name of the default init binary
DefaultInitBinary = "docker-init"
// DefaultRuntimeBinary is the default runtime to be used by
// containerd if none is specified
DefaultRuntimeBinary = "runc"
// DefaultContainersNamespace is the name of the default containerd namespace used for users containers.
DefaultContainersNamespace = "moby"
// DefaultPluginNamespace is the name of the default containerd namespace used for plugins.
DefaultPluginNamespace = "plugins.moby"
// LinuxV2RuntimeName is the runtime used to specify the containerd v2 runc shim
LinuxV2RuntimeName = "io.containerd.runc.v2"
// SeccompProfileDefault is the built-in default seccomp profile.
SeccompProfileDefault = "builtin"
// SeccompProfileUnconfined is a special profile name for seccomp to use an
// "unconfined" seccomp profile.
SeccompProfileUnconfined = "unconfined"
)
var builtinRuntimes = map[string]bool{
StockRuntimeName: true,
LinuxV2RuntimeName: true,
}
// flatOptions contains configuration keys
// that MUST NOT be parsed as deep structures.
// Use this to differentiate these options
// with others like the ones in CommonTLSOptions.
var flatOptions = map[string]bool{
"cluster-store-opts": true,
"log-opts": true,
"runtimes": true,
"default-ulimits": true,
"features": true,
"builder": true,
}
// skipValidateOptions contains configuration keys
// that will be skipped from findConfigurationConflicts
// for unknown flag validation.
var skipValidateOptions = map[string]bool{
"features": true,
"builder": true,
// Corresponding flag has been removed because it was already unusable
"deprecated-key-path": true,
}
// skipDuplicates contains configuration keys that
// will be skipped when checking duplicated
// configuration field defined in both daemon
// config file and from dockerd cli flags.
// This allows some configurations to be merged
// during the parsing.
var skipDuplicates = map[string]bool{
"runtimes": true,
}
// LogConfig represents the default log configuration.
// It includes json tags to deserialize configuration from a file
// using the same names that the flags in the command line use.
type LogConfig struct {
Type string `json:"log-driver,omitempty"`
Config map[string]string `json:"log-opts,omitempty"`
}
// commonBridgeConfig stores all the platform-common bridge driver specific
// configuration.
type commonBridgeConfig struct {
Iface string `json:"bridge,omitempty"`
FixedCIDR string `json:"fixed-cidr,omitempty"`
}
// NetworkConfig stores the daemon-wide networking configurations
type NetworkConfig struct {
// Default address pools for docker networks
DefaultAddressPools opts.PoolsOpt `json:"default-address-pools,omitempty"`
// NetworkControlPlaneMTU allows to specify the control plane MTU, this will allow to optimize the network use in some components
NetworkControlPlaneMTU int `json:"network-control-plane-mtu,omitempty"`
}
// CommonTLSOptions defines TLS configuration for the daemon server.
// It includes json tags to deserialize configuration from a file
// using the same names that the flags in the command line use.
type CommonTLSOptions struct {
CAFile string `json:"tlscacert,omitempty"`
CertFile string `json:"tlscert,omitempty"`
KeyFile string `json:"tlskey,omitempty"`
}
// DNSConfig defines the DNS configurations.
type DNSConfig struct {
DNS []string `json:"dns,omitempty"`
DNSOptions []string `json:"dns-opts,omitempty"`
DNSSearch []string `json:"dns-search,omitempty"`
HostGatewayIP net.IP `json:"host-gateway-ip,omitempty"`
}
// CommonConfig defines the configuration of a docker daemon which is
// common across platforms.
// It includes json tags to deserialize configuration from a file
// using the same names that the flags in the command line use.
type CommonConfig struct {
AuthzMiddleware *authorization.Middleware `json:"-"`
AuthorizationPlugins []string `json:"authorization-plugins,omitempty"` // AuthorizationPlugins holds list of authorization plugins
AutoRestart bool `json:"-"`
Context map[string][]string `json:"-"`
DisableBridge bool `json:"-"`
ExecOptions []string `json:"exec-opts,omitempty"`
GraphDriver string `json:"storage-driver,omitempty"`
GraphOptions []string `json:"storage-opts,omitempty"`
Labels []string `json:"labels,omitempty"`
Mtu int `json:"mtu,omitempty"`
NetworkDiagnosticPort int `json:"network-diagnostic-port,omitempty"`
Pidfile string `json:"pidfile,omitempty"`
RawLogs bool `json:"raw-logs,omitempty"`
RootDeprecated string `json:"graph,omitempty"` // Deprecated: use Root instead. TODO(thaJeztah): remove in next release.
Root string `json:"data-root,omitempty"`
ExecRoot string `json:"exec-root,omitempty"`
SocketGroup string `json:"group,omitempty"`
CorsHeaders string `json:"api-cors-header,omitempty"`
// Proxies holds the proxies that are configured for the daemon.
Proxies `json:"proxies"`
// TrustKeyPath is used to generate the daemon ID and for signing schema 1 manifests
// when pushing to a registry which does not support schema 2. This field is marked as
// deprecated because schema 1 manifests are deprecated in favor of schema 2 and the
// daemon ID will use a dedicated identifier not shared with exported signatures.
TrustKeyPath string `json:"deprecated-key-path,omitempty"`
// LiveRestoreEnabled determines whether we should keep containers
// alive upon daemon shutdown/start
LiveRestoreEnabled bool `json:"live-restore,omitempty"`
// ClusterStore is the storage backend used for the cluster information. It is used by both
// multihost networking (to store networks and endpoints information) and by the node discovery
// mechanism.
// Deprecated: host-discovery and overlay networks with external k/v stores are deprecated
ClusterStore string `json:"cluster-store,omitempty"`
// ClusterOpts is used to pass options to the discovery package for tuning libkv settings, such
// as TLS configuration settings.
// Deprecated: host-discovery and overlay networks with external k/v stores are deprecated
ClusterOpts map[string]string `json:"cluster-store-opts,omitempty"`
// ClusterAdvertise is the network endpoint that the Engine advertises for the purpose of node
// discovery. This should be a 'host:port' combination on which that daemon instance is
// reachable by other hosts.
// Deprecated: host-discovery and overlay networks with external k/v stores are deprecated
ClusterAdvertise string `json:"cluster-advertise,omitempty"`
// MaxConcurrentDownloads is the maximum number of downloads that
// may take place at a time for each pull.
MaxConcurrentDownloads int `json:"max-concurrent-downloads,omitempty"`
// MaxConcurrentUploads is the maximum number of uploads that
// may take place at a time for each push.
MaxConcurrentUploads int `json:"max-concurrent-uploads,omitempty"`
// MaxDownloadAttempts is the maximum number of attempts that
// may take place at a time for each push.
MaxDownloadAttempts int `json:"max-download-attempts,omitempty"`
// ShutdownTimeout is the timeout value (in seconds) the daemon will wait for the container
// to stop when daemon is being shutdown
ShutdownTimeout int `json:"shutdown-timeout,omitempty"`
Debug bool `json:"debug,omitempty"`
Hosts []string `json:"hosts,omitempty"`
LogLevel string `json:"log-level,omitempty"`
TLS *bool `json:"tls,omitempty"`
TLSVerify *bool `json:"tlsverify,omitempty"`
// Embedded structs that allow config
// deserialization without the full struct.
CommonTLSOptions
// SwarmDefaultAdvertiseAddr is the default host/IP or network interface
// to use if a wildcard address is specified in the ListenAddr value
// given to the /swarm/init endpoint and no advertise address is
// specified.
SwarmDefaultAdvertiseAddr string `json:"swarm-default-advertise-addr"`
// SwarmRaftHeartbeatTick is the number of ticks in time for swarm mode raft quorum heartbeat
// Typical value is 1
SwarmRaftHeartbeatTick uint32 `json:"swarm-raft-heartbeat-tick"`
// SwarmRaftElectionTick is the number of ticks to elapse before followers in the quorum can propose
// a new round of leader election. Default, recommended value is at least 10X that of Heartbeat tick.
// Higher values can make the quorum less sensitive to transient faults in the environment, but this also
// means it takes longer for the managers to detect a down leader.
SwarmRaftElectionTick uint32 `json:"swarm-raft-election-tick"`
MetricsAddress string `json:"metrics-addr"`
DNSConfig
LogConfig
BridgeConfig // bridgeConfig holds bridge network specific configuration.
NetworkConfig
registry.ServiceOptions
sync.Mutex
// FIXME(vdemeester) This part is not that clear and is mainly dependent on cli flags
// It should probably be handled outside this package.
ValuesSet map[string]interface{} `json:"-"`
Experimental bool `json:"experimental"` // Experimental indicates whether experimental features should be exposed or not
// Exposed node Generic Resources
// e.g: ["orange=red", "orange=green", "orange=blue", "apple=3"]
NodeGenericResources []string `json:"node-generic-resources,omitempty"`
// ContainerAddr is the address used to connect to containerd if we're
// not starting it ourselves
ContainerdAddr string `json:"containerd,omitempty"`
// CriContainerd determines whether a supervised containerd instance
// should be configured with the CRI plugin enabled. This allows using
// Docker's containerd instance directly with a Kubernetes kubelet.
CriContainerd bool `json:"cri-containerd,omitempty"`
// Features contains a list of feature key value pairs indicating what features are enabled or disabled.
// If a certain feature doesn't appear in this list then it's unset (i.e. neither true nor false).
Features map[string]bool `json:"features,omitempty"`
Builder BuilderConfig `json:"builder,omitempty"`
ContainerdNamespace string `json:"containerd-namespace,omitempty"`
ContainerdPluginNamespace string `json:"containerd-plugin-namespace,omitempty"`
DefaultRuntime string `json:"default-runtime,omitempty"`
}
// Proxies holds the proxies that are configured for the daemon.
type Proxies struct {
HTTPProxy string `json:"http-proxy,omitempty"`
HTTPSProxy string `json:"https-proxy,omitempty"`
NoProxy string `json:"no-proxy,omitempty"`
}
// IsValueSet returns true if a configuration value
// was explicitly set in the configuration file.
func (conf *Config) IsValueSet(name string) bool {
if conf.ValuesSet == nil {
return false
}
_, ok := conf.ValuesSet[name]
return ok
}
// New returns a new fully initialized Config struct
func New() *Config {
return &Config{
CommonConfig: CommonConfig{
ShutdownTimeout: DefaultShutdownTimeout,
LogConfig: LogConfig{
Config: make(map[string]string),
},
MaxConcurrentDownloads: DefaultMaxConcurrentDownloads,
MaxConcurrentUploads: DefaultMaxConcurrentUploads,
MaxDownloadAttempts: DefaultDownloadAttempts,
Mtu: DefaultNetworkMtu,
NetworkConfig: NetworkConfig{
NetworkControlPlaneMTU: DefaultNetworkMtu,
},
ContainerdNamespace: DefaultContainersNamespace,
ContainerdPluginNamespace: DefaultPluginNamespace,
DefaultRuntime: StockRuntimeName,
},
}
}
// GetConflictFreeLabels validates Labels for conflict
// In swarm the duplicates for labels are removed
// so we only take same values here, no conflict values
// If the key-value is the same we will only take the last label
func GetConflictFreeLabels(labels []string) ([]string, error) {
labelMap := map[string]string{}
for _, label := range labels {
stringSlice := strings.SplitN(label, "=", 2)
if len(stringSlice) > 1 {
// If there is a conflict we will return an error
if v, ok := labelMap[stringSlice[0]]; ok && v != stringSlice[1] {
return nil, fmt.Errorf("conflict labels for %s=%s and %s=%s", stringSlice[0], stringSlice[1], stringSlice[0], v)
}
labelMap[stringSlice[0]] = stringSlice[1]
}
}
newLabels := []string{}
for k, v := range labelMap {
newLabels = append(newLabels, fmt.Sprintf("%s=%s", k, v))
}
return newLabels, nil
}
// Reload reads the configuration in the host and reloads the daemon and server.
func Reload(configFile string, flags *pflag.FlagSet, reload func(*Config)) error {
logrus.Infof("Got signal to reload configuration, reloading from: %s", configFile)
newConfig, err := getConflictFreeConfiguration(configFile, flags)
if err != nil {
if flags.Changed("config-file") || !os.IsNotExist(err) {
return errors.Wrapf(err, "unable to configure the Docker daemon with file %s", configFile)
}
newConfig = New()
}
// Check if duplicate label-keys with different values are found
newLabels, err := GetConflictFreeLabels(newConfig.Labels)
if err != nil {
return err
}
newConfig.Labels = newLabels
// TODO(thaJeztah) This logic is problematic and needs a rewrite;
// This is validating newConfig before the "reload()" callback is executed.
// At this point, newConfig may be a partial configuration, to be merged
// with the existing configuration in the "reload()" callback. Validating
// this config before it's merged can result in incorrect validation errors.
//
// However, the current "reload()" callback we use is DaemonCli.reloadConfig(),
// which includes a call to Daemon.Reload(), which both performs "merging"
// and validation, as well as actually updating the daemon configuration.
// Calling DaemonCli.reloadConfig() *before* validation, could thus lead to
// a failure in that function (making the reload non-atomic).
//
// While *some* errors could always occur when applying/updating the config,
// we should make it more atomic, and;
//
// 1. get (a copy of) the active configuration
// 2. get the new configuration
// 3. apply the (reloadable) options from the new configuration
// 4. validate the merged results
// 5. apply the new configuration.
if err := Validate(newConfig); err != nil {
return errors.Wrap(err, "file configuration validation failed")
}
reload(newConfig)
return nil
}
// boolValue is an interface that boolean value flags implement
// to tell the command line how to make -name equivalent to -name=true.
type boolValue interface {
IsBoolFlag() bool
}
// MergeDaemonConfigurations reads a configuration file,
// loads the file configuration in an isolated structure,
// and merges the configuration provided from flags on top
// if there are no conflicts.
func MergeDaemonConfigurations(flagsConfig *Config, flags *pflag.FlagSet, configFile string) (*Config, error) {
fileConfig, err := getConflictFreeConfiguration(configFile, flags)
if err != nil {
return nil, err
}
// merge flags configuration on top of the file configuration
if err := mergo.Merge(fileConfig, flagsConfig); err != nil {
return nil, err
}
// validate the merged fileConfig and flagsConfig
if err := Validate(fileConfig); err != nil {
return nil, errors.Wrap(err, "merged configuration validation from file and command line flags failed")
}
return fileConfig, nil
}
// getConflictFreeConfiguration loads the configuration from a JSON file.
// It compares that configuration with the one provided by the flags,
// and returns an error if there are conflicts.
func getConflictFreeConfiguration(configFile string, flags *pflag.FlagSet) (*Config, error) {
b, err := os.ReadFile(configFile)
if err != nil {
return nil, err
}
var config Config
b = bytes.TrimSpace(b)
if len(b) == 0 {
// empty config file
return &config, nil
}
if flags != nil {
var jsonConfig map[string]interface{}
if err := json.Unmarshal(b, &jsonConfig); err != nil {
return nil, err
}
configSet := configValuesSet(jsonConfig)
if err := findConfigurationConflicts(configSet, flags); err != nil {
return nil, err
}
// Override flag values to make sure the values set in the config file with nullable values, like `false`,
// are not overridden by default truthy values from the flags that were not explicitly set.
// See https://github.com/docker/docker/issues/20289 for an example.
//
// TODO: Rewrite configuration logic to avoid same issue with other nullable values, like numbers.
namedOptions := make(map[string]interface{})
for key, value := range configSet {
f := flags.Lookup(key)
if f == nil { // ignore named flags that don't match
namedOptions[key] = value
continue
}
if _, ok := f.Value.(boolValue); ok {
f.Value.Set(fmt.Sprintf("%v", value))
}
}
if len(namedOptions) > 0 {
// set also default for mergeVal flags that are boolValue at the same time.
flags.VisitAll(func(f *pflag.Flag) {
if opt, named := f.Value.(opts.NamedOption); named {
v, set := namedOptions[opt.Name()]
_, boolean := f.Value.(boolValue)
if set && boolean {
f.Value.Set(fmt.Sprintf("%v", v))
}
}
})
}
config.ValuesSet = configSet
}
if err := json.Unmarshal(b, &config); err != nil {
return nil, err
}
return &config, nil
}
// configValuesSet returns the configuration values explicitly set in the file.
func configValuesSet(config map[string]interface{}) map[string]interface{} {
flatten := make(map[string]interface{})
for k, v := range config {
if m, isMap := v.(map[string]interface{}); isMap && !flatOptions[k] {
for km, vm := range m {
flatten[km] = vm
}
continue
}
flatten[k] = v
}
return flatten
}
// findConfigurationConflicts iterates over the provided flags searching for
// duplicated configurations and unknown keys. It returns an error with all the conflicts if
// it finds any.
func findConfigurationConflicts(config map[string]interface{}, flags *pflag.FlagSet) error {
// 1. Search keys from the file that we don't recognize as flags.
unknownKeys := make(map[string]interface{})
for key, value := range config {
if flag := flags.Lookup(key); flag == nil && !skipValidateOptions[key] {
unknownKeys[key] = value
}
}
// 2. Discard values that implement NamedOption.
// Their configuration name differs from their flag name, like `labels` and `label`.
if len(unknownKeys) > 0 {
unknownNamedConflicts := func(f *pflag.Flag) {
if namedOption, ok := f.Value.(opts.NamedOption); ok {
delete(unknownKeys, namedOption.Name())
}
}
flags.VisitAll(unknownNamedConflicts)
}
if len(unknownKeys) > 0 {
var unknown []string
for key := range unknownKeys {
unknown = append(unknown, key)
}
return fmt.Errorf("the following directives don't match any configuration option: %s", strings.Join(unknown, ", "))
}
var conflicts []string
printConflict := func(name string, flagValue, fileValue interface{}) string {
switch name {
case "http-proxy", "https-proxy":
flagValue = MaskCredentials(flagValue.(string))
fileValue = MaskCredentials(fileValue.(string))
}
return fmt.Sprintf("%s: (from flag: %v, from file: %v)", name, flagValue, fileValue)
}
// 3. Search keys that are present as a flag and as a file option.
duplicatedConflicts := func(f *pflag.Flag) {
// search option name in the json configuration payload if the value is a named option
if namedOption, ok := f.Value.(opts.NamedOption); ok {
if optsValue, ok := config[namedOption.Name()]; ok && !skipDuplicates[namedOption.Name()] {
conflicts = append(conflicts, printConflict(namedOption.Name(), f.Value.String(), optsValue))
}
} else {
// search flag name in the json configuration payload
for _, name := range []string{f.Name, f.Shorthand} {
if value, ok := config[name]; ok && !skipDuplicates[name] {
conflicts = append(conflicts, printConflict(name, f.Value.String(), value))
break
}
}
}
}
flags.Visit(duplicatedConflicts)
if len(conflicts) > 0 {
return fmt.Errorf("the following directives are specified both as a flag and in the configuration file: %s", strings.Join(conflicts, ", "))
}
return nil
}
// Validate validates some specific configs.
// such as config.DNS, config.Labels, config.DNSSearch,
// as well as config.MaxConcurrentDownloads, config.MaxConcurrentUploads and config.MaxDownloadAttempts.
func Validate(config *Config) error {
//nolint:staticcheck // TODO(thaJeztah): remove in next release.
if config.RootDeprecated != "" {
return errors.New(`the "graph" config file option is deprecated; use "data-root" instead`)
}
// validate log-level
if config.LogLevel != "" {
if _, err := logrus.ParseLevel(config.LogLevel); err != nil {
return fmt.Errorf("invalid logging level: %s", config.LogLevel)
}
}
// validate DNS
for _, dns := range config.DNS {
if _, err := opts.ValidateIPAddress(dns); err != nil {
return err
}
}
// validate DNSSearch
for _, dnsSearch := range config.DNSSearch {
if _, err := opts.ValidateDNSSearch(dnsSearch); err != nil {
return err
}
}
// validate Labels
for _, label := range config.Labels {
if _, err := opts.ValidateLabel(label); err != nil {
return err
}
}
// TODO(thaJeztah) Validations below should not accept "0" to be valid; see Validate() for a more in-depth description of this problem
if config.Mtu < 0 {
return fmt.Errorf("invalid default MTU: %d", config.Mtu)
}
if config.MaxConcurrentDownloads < 0 {
return fmt.Errorf("invalid max concurrent downloads: %d", config.MaxConcurrentDownloads)
}
if config.MaxConcurrentUploads < 0 {
return fmt.Errorf("invalid max concurrent uploads: %d", config.MaxConcurrentUploads)
}
if config.MaxDownloadAttempts < 0 {
return fmt.Errorf("invalid max download attempts: %d", config.MaxDownloadAttempts)
}
// validate that "default" runtime is not reset
if runtimes := config.GetAllRuntimes(); len(runtimes) > 0 {
if _, ok := runtimes[StockRuntimeName]; ok {
return fmt.Errorf("runtime name '%s' is reserved", StockRuntimeName)
}
}
if _, err := ParseGenericResources(config.NodeGenericResources); err != nil {
return err
}
if defaultRuntime := config.GetDefaultRuntimeName(); defaultRuntime != "" {
if !builtinRuntimes[defaultRuntime] {
runtimes := config.GetAllRuntimes()
if _, ok := runtimes[defaultRuntime]; !ok && !IsPermissibleC8dRuntimeName(defaultRuntime) {
return fmt.Errorf("specified default runtime '%s' does not exist", defaultRuntime)
}
}
}
for _, h := range config.Hosts {
if _, err := opts.ValidateHost(h); err != nil {
return err
}
}
// validate platform-specific settings
return config.ValidatePlatformConfig()
}
// GetDefaultRuntimeName returns the current default runtime
func (conf *Config) GetDefaultRuntimeName() string {
conf.Lock()
rt := conf.DefaultRuntime
conf.Unlock()
return rt
}
// MaskCredentials masks credentials that are in an URL.
func MaskCredentials(rawURL string) string {
parsedURL, err := url.Parse(rawURL)
if err != nil || parsedURL.User == nil {
return rawURL
}
parsedURL.User = url.UserPassword("xxxxx", "xxxxx")
return parsedURL.String()
}
// IsPermissibleC8dRuntimeName tests whether name is safe to pass into
// containerd as a runtime name, and whether the name is well-formed.
// It does not check if the runtime is installed.
//
// A runtime name containing slash characters is interpreted by containerd as
// the path to a runtime binary. If we allowed this, anyone with Engine API
// access could get containerd to execute an arbitrary binary as root. Although
// Engine API access is already equivalent to root on the host, the runtime name
// has not historically been a vector to run arbitrary code as root so users are
// not expecting it to become one.
//
// This restriction is not configurable. There are viable workarounds for
// legitimate use cases: administrators and runtime developers can make runtimes
// available for use with Docker by installing them onto PATH following the
// [binary naming convention] for containerd Runtime v2.
//
// [binary naming convention]: https://github.com/containerd/containerd/blob/main/runtime/v2/README.md#binary-naming
func IsPermissibleC8dRuntimeName(name string) bool {
// containerd uses a rather permissive test to validate runtime names:
//
// - Any name for which filepath.IsAbs(name) is interpreted as the absolute
// path to a shim binary. We want to block this behaviour.
// - Any name which contains at least one '.' character and no '/' characters
// and does not begin with a '.' character is a valid runtime name. The shim
// binary name is derived from the final two components of the name and
// searched for on the PATH. The name "a.." is technically valid per
// containerd's implementation: it would resolve to a binary named
// "containerd-shim---".
//
// https://github.com/containerd/containerd/blob/11ded166c15f92450958078cd13c6d87131ec563/runtime/v2/manager.go#L297-L317
// https://github.com/containerd/containerd/blob/11ded166c15f92450958078cd13c6d87131ec563/runtime/v2/shim/util.go#L83-L93
return !filepath.IsAbs(name) && !strings.ContainsRune(name, '/') && shim.BinaryName(name) != ""
}