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fix(runtime): bind-mount file secrets to target paths in Apple container runtime #172

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fix(runtime): bind-mount file secrets to target paths in Apple container runtime #172

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73a1a3f
fix(runtime): bind-mount file secrets to target paths in Apple contai…
ryancee Apr 19, 2026
68a1bfc
fix(runtime): clarify MetadataInterception comment for Apple runtime
ryancee Apr 19, 2026
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27 changes: 17 additions & 10 deletions pkg/runtime/apple_container.go
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Original file line number Diff line number Diff line change
Expand Up @@ -18,9 +18,7 @@ import (
"context"
"encoding/json"
"fmt"
"os"
"os/exec"
"path/filepath"
"strings"
"time"

Expand Down Expand Up @@ -48,11 +46,14 @@ func (r *AppleContainerRuntime) ExecUser() string {

func (r *AppleContainerRuntime) Run(ctx context.Context, config RunConfig) (string, error) {
// Stage file, variable, and secret-map secrets before building args
var secretMountSpecs []string
if config.HomeDir != "" && len(config.ResolvedSecrets) > 0 {
containerHome := util.GetHomeDir(config.UnixUsername)
if _, err := writeFileSecrets(config.HomeDir, containerHome, config.ResolvedSecrets); err != nil {
mounts, err := writeFileSecrets(config.HomeDir, containerHome, config.ResolvedSecrets)
if err != nil {
return "", fmt.Errorf("failed to stage file secrets: %w", err)
}
secretMountSpecs = mounts
if err := writeVariableSecrets(config.HomeDir, config.ResolvedSecrets); err != nil {
return "", fmt.Errorf("failed to write variable secrets: %w", err)
}
Expand All @@ -66,6 +67,15 @@ func (r *AppleContainerRuntime) Run(ctx context.Context, config RunConfig) (stri
config.Env = append(config.Env, telemetryGCPCredentialsEnvVar+"="+credPath)
}

// Apple container runtime does not support Linux capabilities (--cap-add NET_ADMIN),
// so iptables-based metadata traffic interception is not available. Disable it here
// to avoid a fatal unsupported-flag error at container startup. Apps that honour the
// GCE_METADATA_HOST / GCE_METADATA_ROOT environment variables (already injected by
// the broker for assign/block modes) will still reach the scion metadata server;
// only apps that bypass those variables and hardcode metadata.google.internal will
// not be intercepted.
config.MetadataInterception = false

args, err := buildCommonRunArgs(config)
if err != nil {
return "", err
Expand Down Expand Up @@ -109,13 +119,10 @@ func (r *AppleContainerRuntime) Run(ctx context.Context, config RunConfig) (stri
// Skip the original 'run', '-d', and '-i' from buildCommonRunArgs (indices 0, 1, 2)
newArgs = append(newArgs, args[3:]...)

// Insert secrets staging directory volume before the image so it is treated
// as a container flag rather than an argument to the container command.
if config.HomeDir != "" && len(config.ResolvedSecrets) > 0 {
secretsDir := filepath.Join(filepath.Dir(config.HomeDir), "secrets")
if _, err := os.Stat(secretsDir); err == nil {
newArgs = insertVolumeFlags(newArgs, config.Image, []string{secretsDir + ":/run/scion-secrets:ro"})
}
// Insert file secret bind-mounts before the image so they are treated as
// container flags rather than arguments to the container command.
if len(secretMountSpecs) > 0 {
newArgs = insertVolumeFlags(newArgs, config.Image, secretMountSpecs)
}

WriteRuntimeDebugFile(config, r.Command, newArgs)
Expand Down