Installer review: secrets are staged privately, and a bundle is 0600 whether or not it existed

From review: the store and broker passwords genesis makes were carried into
the controller through a world-readable file in /tmp, a bundle left at 0644 by
an earlier installer kept that mode while now holding them, a mesh raised by
the old installer would have been handed new passwords its servers do not have,
and the broker-admin action's marker did not depend on the value. Secrets now
stage in a 0700 directory owned by the controller's account; the bundle is
chmod'd; an existing store or broker volume with no credential file is refused
by name; the marker holds the password's fingerprint. Also: one install path
for the store, broker and vault, no error-string matching for the operator
key, and no unreachable fallback for the superuser.

internal/bootstrap/bootstrap.go

@@ -394,6 +394,9 @@ func Run(ctx context.Context, o Options, d Deps, say func(string)) (Result, erro
 	if err != nil {
 		return result, failed(StepBundle, err)
 	}
+	if err := RefuseExistingServers(ctx, d.Run, creds); err != nil {
+		return result, failed(StepBundle, err)
+	}
 	root, err := RewriteRoot(&rewritten, creds)
 	if err != nil {
 		return result, failed(StepBundle, err)
@@ -644,13 +647,13 @@ func Run(ctx context.Context, o Options, d Deps, say func(string)) (Result, erro
 		return result, failed(StepStore, err)
 	}
 
-	// ---- 14b. broker ----------------------------------------------------------------------
+	// ---- broker ---------------------------------------------------------------------------
 	say("broker — the foundation's broker, adopted as the lavinmq module: one bus, not two")
 	if err := InstallBroker(ctx, o, permanentControl, rewritten.Declaration, say); err != nil {
 		return result, failed(StepBroker, err)
 	}
 
-	// ---- 14c. vault -----------------------------------------------------------------------
+	// ---- vault ----------------------------------------------------------------------------
 	// A foundation module (novox/hq ADR 0085, amended): it keeps every operator-sealed secret on
 	// its own disk, outside the store, from the first push that carries one.
 	say("vault — the mesh's secrets get an owner, and their operator-sealed copies a place to live")

internal/bootstrap/control.go

@@ -274,7 +274,7 @@ func deliverStores(ctx context.Context, o Options, control controlPlane, manifes
 		// installer has neither a terminal to be prompted at nor a way to write to a command's
 		// standard input through the runner every applier in this repository shares.
 		at := "/accepting-" + secret
-		if err := control.carrying(ctx, "mesh-accepting-"+secret, []byte(value), at); err != nil {
+		if err := control.carryingSecret(ctx, "mesh-accepting-"+secret, []byte(value), at); err != nil {
 			return delivered, err
 		}
 		if _, err := control.tell(ctx, "secret", "accept", o.Node, ControlPlaneModule, secret,

internal/bootstrap/operator.go

@@ -42,11 +42,14 @@ type OperatorKey struct {
 // MakeOperatorKey makes the key if this machine has none, and tells the mesh its public half.
 func MakeOperatorKey(ctx context.Context, o Options, control controlPlane, say func(string)) (OperatorKey, error) {
 	out := OperatorKey{Path: OperatorKeyFile(o)}
-	key, err := identity.LoadSealingKey(out.Path)
+	var key identity.SealingKey
-	switch {
+	if _, err := os.Stat(out.Path); err == nil {
-	case err == nil:
+		key, err = identity.LoadSealingKey(out.Path)
+		if err != nil {
+			return out, err
+		}
 		say("  operator key      already at " + out.Path + " — kept")
-	case os.IsNotExist(underlying(err)) || strings.Contains(err.Error(), "no sealing key at"):
+	} else if os.IsNotExist(err) {
 		key, err = identity.GenerateSealingKey()
 		if err != nil {
 			return out, err
@@ -58,7 +61,7 @@ func MakeOperatorKey(ctx context.Context, o Options, control controlPlane, say f
 			return out, err
 		}
 		out.Made = true
-	default:
+	} else {
 		return out, err
 	}
 	sum := sha256.Sum256([]byte(key.Public))
@@ -77,16 +80,6 @@ func MakeOperatorKey(ctx context.Context, o Options, control controlPlane, say f
 	return out, nil
 }
 
-func underlying(err error) error {
-	for {
-		next, ok := err.(interface{ Unwrap() error })
-		if !ok || next.Unwrap() == nil {
-			return err
-		}
-		err = next.Unwrap()
-	}
-}
-
 // ExportRootSecrets writes the export beside the operator key: every secret sealed to it, as
 // ciphertext, and the honest list of what is not. What the vault keeps on its disk, kept once
 // more by the person who holds the key.

internal/bootstrap/phase3.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"os"
 	"strings"
 
 	"github.com/novox/mesh-host/internal/declaration"
@@ -73,6 +72,27 @@ func InstallStore(ctx context.Context, o Options, control controlPlane,
 	}
 	say("  adopting          " + store.Name + " — the store the foundation raised, unchanged")
 
+	// The superuser is the foundation's, made at genesis — carried in before the push, or the push
+	// would seal random bytes where a working password has to be and the provisioner would not open
+	// the store it is meant to manage.
+	if err := installProvider(ctx, o, control, module, manifest, "(the provisioner; the server is adopted, not built)",
+		func() error {
+			return deliverCredential(ctx, o, control, module, "superuser", StoreSuperuserFile, "the store's superuser", say)
+		},
+		say); err != nil {
+		return err
+	}
+	say("  adopted           mesh-store — the foundation's store is now the " + module + " module")
+	return nil
+}
+
+// installProvider registers, builds, issues, assigns and pushes one catalogue module, with one
+// thing done just before the push — the moment a credential the mesh could not have made has to
+// be in it. InstallFromCatalogue is the same sequence without that moment; the store, the broker
+// and the vault each need it or need the shape, and three copies of it drifted.
+func installProvider(ctx context.Context, o Options, control controlPlane, module string,
+	manifest []byte, buildNote string, beforePush func() error, say func(string)) error {
+
 	remote := "/" + module + "-module.json"
 	if err := control.carrying(ctx, module+"-module.json", manifest, remote); err != nil {
 		return err
@@ -87,7 +107,7 @@ func InstallStore(ctx context.Context, o Options, control controlPlane,
 			"the catalogue CHECKOUT says what it is, the catalogue REPOSITORY is where a builder "+
 			"clones it", module)
 	}
-	say("  building          " + module + " (the provisioner; the server is adopted, not built)")
+	say(strings.TrimRight("  building          "+module+" "+buildNote, " "))
 	if _, err := control.within(buildWait).tell(ctx, "build", o.CatalogSource.Repository,
 		"--path", "modules/"+module, "--ref", refOr(o.CatalogSource.Ref), "--wait", "1200s"); err != nil {
 		return err
@@ -102,37 +122,40 @@ func InstallStore(ctx context.Context, o Options, control controlPlane,
 	if _, err := control.tell(ctx, "assign", o.Node, module); err != nil {
 		return err
 	}
-
+	if beforePush != nil {
-	// The superuser is the foundation's, made at genesis — carried in before the push, or the push
+		if err := beforePush(); err != nil {
-	// would seal random bytes where a working password has to be and the provisioner would not open
+			return err
-	// the store it is meant to manage.
+		}
-	if err := deliverSuperuser(ctx, o, control, module, store, say); err != nil {
-		return err
 	}
-
+	_, err := pushNode(ctx, o, control, say)
-	if _, err := pushNode(ctx, o, control, say); err != nil {
+	return err
-		return err
-	}
-	say("  adopted           mesh-store — the foundation's store is now the " + module + " module")
-	return nil
 }
 
-func readCredentialFile(path string) (string, error) {
+// deliverCredential carries a credential genesis made into a module as its own secret, through
-	raw, err := os.ReadFile(path)
+// `secret accept`: the mesh cannot invent the value a running server already has.
+func deliverCredential(ctx context.Context, o Options, control controlPlane, module, secret, file, what string,
+	say func(string)) error {
+
+	value, err := readCredentialFile(file)
 	if err != nil {
-		return "", err
+		return fmt.Errorf("%s is not at %s, so the %s module has nothing to open its server with — "+
+			"and the mesh cannot invent the one the server already has: %w", what, file, module, err)
 	}
-	value := strings.TrimRight(string(raw), "\r\n")
+	at := "/accepting-" + secret
-	if value == "" {
+	if err := control.carryingSecret(ctx, "mesh-accepting-"+secret, []byte(value), at); err != nil {
-		return "", fmt.Errorf("%s is empty", path)
+		return err
 	}
-	return value, nil
+	if _, err := control.tell(ctx, "secret", "accept", o.Node, module, secret, "--from", at); err != nil {
+		return err
+	}
+	say("  accepted          " + secret + " — " + what + ", as genesis made it")
+	return nil
 }
 
 // InstallBroker makes the foundation's broker the `lavinmq` module, adopted in place — the same
 // shape as InstallStore, for the same reasons. The administrator's password is the one genesis
-// gave the image's default account (rootsecrets.go), carried in through `secret accept` so the
+// gave the image's default account (rootsecrets.go), carried in so the module's provisioner can
-// module's provisioner can reach the management API as it.
+// reach the management API as it.
 func InstallBroker(ctx context.Context, o Options, control controlPlane,
 	foundation *declaration.Declaration, say func(string)) error {
 
@@ -149,46 +172,11 @@ func InstallBroker(ctx context.Context, o Options, control controlPlane,
 		return err
 	}
 	say("  adopting          " + broker.Name + " — the broker the foundation raised, unchanged")
-
+	if err := installProvider(ctx, o, control, module, manifest, "(the provisioner; the server is adopted, not built)",
-	remote := "/" + module + "-module.json"
+		func() error {
-	if err := control.carrying(ctx, module+"-module.json", manifest, remote); err != nil {
+			return deliverCredential(ctx, o, control, module, "admin", BrokerAdminFile, "the broker's administrator", say)
-		return err
+		},
-	}
+		say); err != nil {
-	if _, err := control.tell(ctx, "module", "add", remote); err != nil {
-		return err
-	}
-	say("  registered        " + module)
-	if o.CatalogSource.Repository == "" {
-		return fmt.Errorf("%s has to be built and there is no --catalog-source to build it from", module)
-	}
-	say("  building          " + module + " (the provisioner; the server is adopted, not built)")
-	if _, err := control.within(buildWait).tell(ctx, "build", o.CatalogSource.Repository,
-		"--path", "modules/"+module, "--ref", refOr(o.CatalogSource.Ref), "--wait", "1200s"); err != nil {
-		return err
-	}
-	if _, err := control.tell(ctx, "module", "issue", module, "--node", o.Node); err != nil {
-		say("  no account        " + module + " — it declares nothing to say on the broker")
-	} else {
-		say("  account issued    " + module)
-	}
-	if _, err := control.tell(ctx, "assign", o.Node, module); err != nil {
-		return err
-	}
-
-	value, err := readCredentialFile(BrokerAdminFile)
-	if err != nil {
-		return fmt.Errorf("the broker's administrator password genesis made is not at %s: %w", BrokerAdminFile, err)
-	}
-	at := "/accepting-admin"
-	if err := control.carrying(ctx, "mesh-accepting-admin", []byte(value), at); err != nil {
-		return err
-	}
-	if _, err := control.tell(ctx, "secret", "accept", o.Node, module, "admin", "--from", at); err != nil {
-		return err
-	}
-	say("  accepted          admin — the broker's administrator, as genesis made it")
-
-	if _, err := pushNode(ctx, o, control, say); err != nil {
 		return err
 	}
 	say("  adopted           " + broker.Name + " — the foundation's broker is now the " + module + " module")
@@ -196,38 +184,15 @@ func InstallBroker(ctx context.Context, o Options, control controlPlane,
 }
 
 // InstallVault installs the vault as a foundation module (novox/hq ADR 0085, amended). Nothing to
-// adopt: it is its own runtime, built from the catalogue like any provider, and from its first push
+// adopt and nothing to carry in: it is its own runtime, built from the catalogue like any provider,
-// it keeps the export of every operator-sealed secret on its own disk.
+// and from its first push it keeps the export of every operator-sealed secret on its own disk.
 func InstallVault(ctx context.Context, o Options, control controlPlane, say func(string)) error {
 	const module = "mesh-vault"
 	manifest, err := readManifest(o.Catalogue, module)
 	if err != nil {
 		return err
 	}
-	remote := "/" + module + "-module.json"
+	if err := installProvider(ctx, o, control, module, manifest, "", nil, say); err != nil {
-	if err := control.carrying(ctx, module+"-module.json", manifest, remote); err != nil {
-		return err
-	}
-	if _, err := control.tell(ctx, "module", "add", remote); err != nil {
-		return err
-	}
-	say("  registered        " + module)
-	if o.CatalogSource.Repository == "" {
-		return fmt.Errorf("%s has to be built and there is no --catalog-source to build it from", module)
-	}
-	say("  building          " + module)
-	if _, err := control.within(buildWait).tell(ctx, "build", o.CatalogSource.Repository,
-		"--path", "modules/"+module, "--ref", refOr(o.CatalogSource.Ref), "--wait", "1200s"); err != nil {
-		return err
-	}
-	if _, err := control.tell(ctx, "module", "issue", module, "--node", o.Node); err != nil {
-		return err
-	}
-	say("  account issued    " + module)
-	if _, err := control.tell(ctx, "assign", o.Node, module); err != nil {
-		return err
-	}
-	if _, err := pushNode(ctx, o, control, say); err != nil {
 		return err
 	}
 	say("  installed         " + module + " — the operator-sealed export now lives on this machine, outside the store")
@@ -294,35 +259,3 @@ func serverMatchesFoundation(manifest []byte, store *declaration.Container, modu
 			"store with. Its server container has to carry the name the foundation raised",
 		module, store.Name)
 }
-
-// deliverSuperuser carries the store's superuser password into the module.
-//
-// It is the foundation's, set on the bundle's store container at genesis; the mesh cannot invent a
-// credential that already made the databases, so it goes in through `secret accept`, exactly as the
-// control plane's store connections do (control.go deliverStores).
-func deliverSuperuser(ctx context.Context, o Options, control controlPlane, module string,
-	store *declaration.Container, say func(string)) error {
-
-	const secret = "superuser"
-	// Genesis made it and kept it in the file the store was raised from (rootsecrets.go); the
-	// template's environment variable is accepted too, for a bundle produced before that.
-	value, err := readCredentialFile(StoreSuperuserFile)
-	if err != nil {
-		value = strings.TrimSpace(store.Env["POSTGRES_PASSWORD"])
-	}
-	if value == "" {
-		return fmt.Errorf(
-			"neither %s nor the foundation's store names the superuser password, so the %s module "+
-				"has nothing to open the store with — and the mesh cannot invent the one that already "+
-				"made the databases", StoreSuperuserFile, module)
-	}
-	at := "/accepting-" + secret
-	if err := control.carrying(ctx, "mesh-accepting-"+secret, []byte(value), at); err != nil {
-		return err
-	}
-	if _, err := control.tell(ctx, "secret", "accept", o.Node, module, secret, "--from", at); err != nil {
-		return err
-	}
-	say("  accepted          " + secret + " — the store's superuser, as the foundation made it")
-	return nil
-}

internal/bootstrap/phase_packages.go

@@ -270,7 +270,7 @@ func packagePasswords() (db, admin, builder string, err error) {
 func deliverBuilderNpm(ctx context.Context, o Options, control controlPlane, password string,
 	say func(string)) error {
 	at := "/accepting-npm-password"
-	if err := control.carrying(ctx, "mesh-accepting-npm-password", []byte(password), at); err != nil {
+	if err := control.carryingSecret(ctx, "mesh-accepting-npm-password", []byte(password), at); err != nil {
 		return err
 	}
 	if _, err := control.tell(ctx, "secret", "accept", o.Node, BuilderModule, "npm-password", "--from", at); err != nil {

internal/bootstrap/rewrite.go

@@ -332,5 +332,10 @@ func writeBundleFile(path string, content []byte) error {
 				"applying something nobody can read afterwards is how a machine becomes a mystery",
 			path, err)
 	}
+	// The mode above applies only when the file is created. A bundle an earlier installer left at
+	// 0644 would keep that while now carrying real credentials, with this function saying 0600.
+	if err := os.Chmod(path, 0o600); err != nil {
+		return fmt.Errorf("cannot make the produced bundle %s readable by root alone: %w", path, err)
+	}
 	return nil
 }

internal/bootstrap/rootsecrets.go

@@ -2,8 +2,11 @@ package bootstrap
 
 import (
 	"bytes"
+	"context"
 	"crypto/rand"
+	"crypto/sha256"
 	"encoding/base64"
+	"encoding/hex"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -80,12 +83,8 @@ func RootSecrets(dryRun bool) (RootCredentials, error) {
 }
 
 func keptOrMade(path string, dryRun bool) (value string, made bool, err error) {
-	raw, err := os.ReadFile(path)
+	value, err = readCredentialFile(path)
 	if err == nil {
-		value = strings.TrimRight(string(raw), "\r\n")
-		if value == "" {
-			return "", false, fmt.Errorf("%s exists and is empty; move it aside to have one made", path)
-		}
 		return value, false, nil
 	}
 	if !os.IsNotExist(err) {
@@ -113,6 +112,27 @@ func keptOrMade(path string, dryRun bool) (value string, made bool, err error) {
 	return value, true, nil
 }
 
+// readCredentialFile is a credential as genesis keeps it: the value alone, its line ending gone.
+// Missing is reported as os.IsNotExist so a caller can tell "not made yet" from "unreadable".
+func readCredentialFile(path string) (string, error) {
+	raw, err := os.ReadFile(path)
+	if err != nil {
+		return "", err
+	}
+	value := strings.TrimRight(string(raw), "\r\n")
+	if value == "" {
+		return "", fmt.Errorf("%s exists and is empty; move it aside to have one made", path)
+	}
+	return value, nil
+}
+
+// credentialFingerprint names a credential without being one — what the broker-admin action
+// leaves on the broker's volume, so its verify holds for this value and not for any value.
+func credentialFingerprint(value string) string {
+	sum := sha256.Sum256([]byte(value))
+	return hex.EncodeToString(sum[:8])
+}
+
 // freshSecret is the same shape the controller mints: 30 random bytes as unpadded base64url, 40
 // characters, URL-safe — it lands inside connection strings.
 func freshSecret() (string, error) {
@@ -123,6 +143,40 @@ func freshSecret() (string, error) {
 	return base64.RawURLEncoding.EncodeToString(b), nil
 }
 
+// RefuseExistingServers stops a run that would put a made credential in front of a server raised
+// by an earlier installer with the template's.
+//
+// The store's password is set by initdb, once, on an empty volume; the broker's by the action
+// above, once. A machine that already holds `mesh-store-data` or `mesh-broker-data` and has no
+// credential file was raised with `bootstrap` and `guest`, and minting new values here would make a
+// bundle that dials with passwords the servers do not have — failing three steps later, in the
+// schemas, with nothing pointing back here. Refused by name instead, with the way forward.
+func RefuseExistingServers(ctx context.Context, run Runner, c RootCredentials) error {
+	for _, check := range []struct {
+		made   bool
+		volume string
+		what   string
+		file   string
+	}{
+		{c.StoreMade, "mesh-store-data", "store", StoreSuperuserFile},
+		{c.BrokerMade, "mesh-broker-data", "broker", BrokerAdminFile},
+	} {
+		if !check.made {
+			continue
+		}
+		if _, err := run(ctx, "docker", "volume", "inspect", check.volume); err != nil {
+			continue // no such volume: a fresh machine, which is the case this installer makes
+		}
+		return fmt.Errorf(
+			"this machine already holds the %s's data (volume %s) and no credential at %s, so it was raised "+
+				"by an earlier installer with the template's password. A new one made here would not open it. "+
+				"Put the password the %s has into %s (0600, the value alone) and run again; then change it "+
+				"on the server and accept the new value — this installer does not rotate a running %s",
+			check.what, check.volume, check.file, check.what, check.file, check.what)
+	}
+	return nil
+}
+
 // RootRewrite says what RewriteRoot did to the bundle.
 type RootRewrite struct {
 	StoreURLs, BrokerURLs int
@@ -162,16 +216,18 @@ func RewriteRoot(r *Rewritten, c RootCredentials) (RootRewrite, error) {
 	bundle = bytes.ReplaceAll(bundle, []byte(templateBrokerURL), []byte(BrokerAdminUser+":"+c.Broker+"@"))
 
 	// The broker's administrator, changed once the broker answers and before anything dials it.
-	// Verified by a marker on the broker's own data volume, because the image carries nothing that
+	// Verified by a marker on the broker's own data volume holding this password's fingerprint —
-	// can try a password from inside; what proves the password is the control plane answering
+	// the image carries nothing that can try a password from inside, and a marker that merely
-	// over it, a few resources later.
+	// existed would let a regenerated password go unapplied for ever. What proves the password
+	// works is the control plane answering over it, a few resources later.
+	fp := credentialFingerprint(c.Broker)
 	action := templateBrokerReady + "\n" +
 		"    {\n" +
 		"      \"id\": \"broker-admin\",\n" +
 		"      \"type\": \"action\",\n" +
 		"      \"in\": \"mesh-broker\",\n" +
-		"      \"command\": [\"sh\", \"-c\", \"lavinmqctl change_password " + BrokerAdminUser + " '" + c.Broker + "' && touch " + brokerAdminMarker + "\"],\n" +
+		"      \"command\": [\"sh\", \"-c\", \"lavinmqctl change_password " + BrokerAdminUser + " '" + c.Broker + "' && printf %s " + fp + " > " + brokerAdminMarker + "\"],\n" +
-		"      \"verify\": [\"sh\", \"-c\", \"test -f " + brokerAdminMarker + "\"]\n" +
+		"      \"verify\": [\"sh\", \"-c\", \"read m < " + brokerAdminMarker + " && [ \\\"$m\\\" = " + fp + " ]\"]\n" +
 		"    },"
 	if bundle, err = replaceOnce(bundle, templateBrokerReady, action, "the broker's readiness check"); err != nil {
 		return out, err

internal/bootstrap/talk.go

@@ -82,11 +82,9 @@ func (c controlPlane) carry(ctx context.Context, local, remote string) error {
 // landed unreadable, `secret accept` failed with `permission denied`, and what depended on it
 // crash-looped on material it never received. There is no shell in the image to chown it with.
 //
-// What goes through here is a module manifest and a store connection string. The connection is the
+// What goes through here is a module manifest — public, the same bytes as in the catalogue. A
-// same value the produced bundle already holds in the clear — a foundation names its own bootstrap
+// value that is secret goes through carryingSecret below. The file on the machine is removed at
-// credentials, and at genesis there is nowhere else for them to be — so this widens nothing. The
+// once, and the copy inside the container goes when the container does.
-// file on the machine is removed at once, and the copy inside the container goes when the
-// container does, which for the temporary control plane is step 10.
 func (c controlPlane) carrying(ctx context.Context, name string, content []byte, remote string) error {
 	local := filepath.Join(os.TempDir(), name)
 	if err := os.WriteFile(local, content, 0o644); err != nil {
@@ -96,6 +94,38 @@ func (c controlPlane) carrying(ctx context.Context, name string, content []byte,
 	return c.carry(ctx, local, remote)
 }
 
+// controlPlaneUID is the account the control plane's image runs as — `USER 65534:65534` in its
+// Dockerfile — and so the only account inside the container that needs to read what is carried in.
+const controlPlaneUID = 65534
+
+// carryingSecret is carrying for a value that is a secret: staged in a directory only root can
+// enter, at 0600, owned by the control plane's own account — which `docker cp` keeps, so inside
+// the container the file is readable by the process that must read it and by nobody else. Since
+// genesis makes the mesh's root credentials rather than copying the template's (rootsecrets.go),
+// a store connection string or a broker password carried this way is a real secret, and 0644 in a
+// shared temporary directory would hand it to any local user for the length of the copy.
+func (c controlPlane) carryingSecret(ctx context.Context, name string, content []byte, remote string) error {
+	dir, err := os.MkdirTemp("", "mesh-carrying-")
+	if err != nil {
+		return fmt.Errorf("nowhere to stage %s before copying it into %s: %w", name, c.container, err)
+	}
+	defer os.RemoveAll(dir)
+	local := filepath.Join(dir, name)
+	if err := os.WriteFile(local, content, 0o600); err != nil {
+		return fmt.Errorf("nowhere to stage %s before copying it into %s: %w", name, c.container, err)
+	}
+	if err := os.Chown(local, controlPlaneUID, controlPlaneUID); err != nil {
+		// Not root — a test, or an installer run as a user, which no real genesis is. The
+		// directory is 0700, so nobody else on the machine can reach the file either way; inside
+		// the container the only account is the control plane's, so 0644 there is read by it and
+		// by nothing else. The narrower ownership is taken whenever it can be.
+		if err := os.Chmod(local, 0o644); err != nil {
+			return err
+		}
+	}
+	return c.carry(ctx, local, remote)
+}
+
 func indent(s string) string {
 	if s == "" {
 		return ""