fix: keep the runner's own container.options when privileged is off (#1151)

The runner's own `container.options` and the workflow's were joined into one string before parsing, so the host-escape filter added in https://gitea.com/gitea/runner/pulls/1058 dropped the administrator's options along with the workflow's. Setups that need `--device` or `--security-opt` from the config file had no way left to get them short of enabling privileged mode.

`NewContainerInput` now carries the two sources apart, as `RunnerOptions` and `WorkflowOptions`, down to the point where the filter runs. With privileged mode off, the host-escape fields are reset to what the runner's own options parse to on their own, so only the workflow's contribution is dropped.

Three further ways a workflow's options reached past its container, all resolved on the runner before anything reaches the daemon:

1. `--env-file` and `--label-file` name files that are read on the runner, so any file it could read became container environment or labels. Both are refused from a workflow now, and still serve the runner's own options.
2. A bare `--env NAME` was resolved from the runner's own environment by docker's validator. That lookup is gone, for every source. Use `runner.envs` or `runner.env_file` to pass a variable on.
3. A volume driver decides for itself what it mounts, and the local driver's `device=` option turns a name `valid_volumes` allows into a bind of any host path. A workflow's mounts may no longer carry one.

`--isolation`, `--volume-driver` and the two paths `--security-opt systempaths=unconfined` lands in were also missing from the fields a workflow may not set.

Last, the `--network and --net in the options will be ignored.` warning fired for every container, because the runner's own network mode is fed into the parsed options before the check runs.

Fixes https://gitea.com/gitea/runner/issues/1142

Reviewed-on: https://gitea.com/gitea/runner/pulls/1151
Reviewed-by: bircni <bircni@icloud.com>
Co-authored-by: silverwind <me@silverwind.io>

act/container/docker_create_flags.go

@@ -10,7 +10,9 @@ import (
 	"fmt"
 	"io"
 	"slices"
+	"strings"
 
+	"github.com/docker/cli/opts"
 	"github.com/kballard/go-shellquote"
 	"github.com/spf13/pflag"
 )
@@ -51,6 +53,7 @@ func parseContainerOptions(options string) (*pflag.FlagSet, *containerOptions, *
 	flags := pflag.NewFlagSet("container_flags", pflag.ContinueOnError)
 	flags.SetOutput(io.Discard)
 	copts := addFlags(flags)
+	copts.env = opts.NewListOpts(validateEnv) // addFlags registered this field's address, so the swap takes effect
 	cf := registerCreateFlags(flags)
 
 	args, err := shellquote.Split(options)
@@ -73,6 +76,30 @@ func createFlagsFromOptions(options string) *createFlags {
 	return cf
 }
 
+// validateEnv is opts.ValidateEnv without its lookup of a bare name in the runner's environment.
+func validateEnv(val string) (string, error) {
+	if name, _, _ := strings.Cut(val, "="); name == "" {
+		return "", errors.New("invalid environment variable: " + val)
+	}
+	return val, nil
+}
+
+// rejectHostReadingOptions refuses the flags naming files that are read here, on the
+// runner, rather than in the container.
+func rejectHostReadingOptions(options string) error {
+	flags, _, _, err := parseContainerOptions(options)
+	if err != nil {
+		return err
+	}
+
+	for _, name := range []string{"env-file", "label-file"} {
+		if flags.Changed(name) {
+			return fmt.Errorf("container option --%s reads files from the runner and is not allowed in a workflow", name)
+		}
+	}
+	return nil
+}
+
 func (cf *createFlags) validate() error {
 	if !slices.Contains(pullPolicies, cf.pull) {
 		return fmt.Errorf("invalid --pull option %q: must be one of %q", cf.pull, pullPolicies)