3 files changed, 70 insertions, 4 deletions
diff --git a/cmd/podman/common/sign.go b/cmd/podman/common/sign.go
new file mode 100644
index 000000000..e8a90ed57
--- /dev/null
+++ b/cmd/podman/common/sign.go
@@ -0,0 +1,36 @@
+package common
+
+import (
+	"fmt"
+
+	"github.com/containers/image/v5/pkg/cli"
+	"github.com/containers/podman/v4/pkg/domain/entities"
+	"github.com/containers/podman/v4/pkg/terminal"
+)
+
+// PrepareSigningPassphrase updates pushOpts.SignPassphrase and SignSigstorePrivateKeyPassphrase based on a --sign-passphrase-file value signPassphraseFile,
+// and validates pushOpts.Sign* consistency.
+// It may interactively prompt for a passphrase if one is required and wasn’t provided otherwise.
+func PrepareSigningPassphrase(pushOpts *entities.ImagePushOptions, signPassphraseFile string) error {
+	// c/common/libimage.Image does allow creating both simple signing and sigstore signatures simultaneously,
+	// with independent passphrases, but that would make the CLI probably too confusing.
+	// For now, use the passphrase with either, but only one of them.
+	if signPassphraseFile != "" && pushOpts.SignBy != "" && pushOpts.SignBySigstorePrivateKeyFile != "" {
+		return fmt.Errorf("only one of --sign-by and sign-by-sigstore-private-key can be used with --sign-passphrase-file")
+	}
+
+	var passphrase string
+	if signPassphraseFile != "" {
+		p, err := cli.ReadPassphraseFile(signPassphraseFile)
+		if err != nil {
+			return err
+		}
+		passphrase = p
+	} else if pushOpts.SignBySigstorePrivateKeyFile != "" {
+		p := terminal.ReadPassphrase()
+		passphrase = string(p)
+	} // pushOpts.SignBy triggers a GPG-agent passphrase prompt, possibly using a more secure channel, so we usually shouldn’t prompt ourselves if no passphrase was explicitly provided.
+	pushOpts.SignPassphrase = passphrase
+	pushOpts.SignSigstorePrivateKeyPassphrase = []byte(passphrase)
+	return nil
+}
diff --git a/cmd/podman/images/push.go b/cmd/podman/images/push.go
index 764936426..1734900de 100644
--- a/cmd/podman/images/push.go
+++ b/cmd/podman/images/push.go
@@ -17,8 +17,9 @@ import (
 // CLI-only fields into the API types.
 type pushOptionsWrapper struct {
 	entities.ImagePushOptions
-	TLSVerifyCLI   bool // CLI only
-	CredentialsCLI string
+	TLSVerifyCLI          bool // CLI only
+	CredentialsCLI        string
+	SignPassphraseFileCLI string
 }
 
 var (
@@ -106,6 +107,14 @@ func pushFlags(cmd *cobra.Command) {
 	flags.StringVar(&pushOptions.SignBy, signByFlagName, "", "Add a signature at the destination using the specified key")
 	_ = cmd.RegisterFlagCompletionFunc(signByFlagName, completion.AutocompleteNone)
 
+	signBySigstorePrivateKeyFlagName := "sign-by-sigstore-private-key"
+	flags.StringVar(&pushOptions.SignBySigstorePrivateKeyFile, signBySigstorePrivateKeyFlagName, "", "Sign the image using a sigstore private key at `PATH`")
+	_ = cmd.RegisterFlagCompletionFunc(signBySigstorePrivateKeyFlagName, completion.AutocompleteDefault)
+
+	signPassphraseFileFlagName := "sign-passphrase-file"
+	flags.StringVar(&pushOptions.SignPassphraseFileCLI, signPassphraseFileFlagName, "", "Read a passphrase for signing an image from `PATH`")
+	_ = cmd.RegisterFlagCompletionFunc(signPassphraseFileFlagName, completion.AutocompleteDefault)
+
 	flags.BoolVar(&pushOptions.TLSVerifyCLI, "tls-verify", true, "Require HTTPS and verify certificates when contacting registries")
 
 	compressionFormat := "compression-format"
@@ -118,6 +127,8 @@ func pushFlags(cmd *cobra.Command) {
 		_ = flags.MarkHidden("digestfile")
 		_ = flags.MarkHidden("quiet")
 		_ = flags.MarkHidden(signByFlagName)
+		_ = flags.MarkHidden(signBySigstorePrivateKeyFlagName)
+		_ = flags.MarkHidden(signPassphraseFileFlagName)
 	}
 	if !registry.IsRemote() {
 		flags.StringVar(&pushOptions.SignaturePolicy, "signature-policy", "", "Path to a signature-policy file")
@@ -153,6 +164,10 @@ func imagePush(cmd *cobra.Command, args []string) error {
 		pushOptions.Password = creds.Password
 	}
 
+	if err := common.PrepareSigningPassphrase(&pushOptions.ImagePushOptions, pushOptions.SignPassphraseFileCLI); err != nil {
+		return err
+	}
+
 	// Let's do all the remaining Yoga in the API to prevent us from scattering
 	// logic across (too) many parts of the code.
 	return registry.ImageEngine().Push(registry.GetContext(), source, destination, pushOptions.ImagePushOptions)
diff --git a/cmd/podman/manifest/push.go b/cmd/podman/manifest/push.go
index df394d275..6afd8ea4c 100644
--- a/cmd/podman/manifest/push.go
+++ b/cmd/podman/manifest/push.go
@@ -20,8 +20,9 @@ import (
 type manifestPushOptsWrapper struct {
 	entities.ImagePushOptions
 
-	TLSVerifyCLI   bool // CLI only
-	CredentialsCLI string
+	TLSVerifyCLI          bool // CLI only
+	CredentialsCLI        string
+	SignPassphraseFileCLI string
 }
 
 var (
@@ -72,6 +73,14 @@ func init() {
 	flags.StringVar(&manifestPushOpts.SignBy, signByFlagName, "", "sign the image using a GPG key with the specified `FINGERPRINT`")
 	_ = pushCmd.RegisterFlagCompletionFunc(signByFlagName, completion.AutocompleteNone)
 
+	signBySigstorePrivateKeyFlagName := "sign-by-sigstore-private-key"
+	flags.StringVar(&manifestPushOpts.SignBySigstorePrivateKeyFile, signBySigstorePrivateKeyFlagName, "", "Sign the image using a sigstore private key at `PATH`")
+	_ = pushCmd.RegisterFlagCompletionFunc(signBySigstorePrivateKeyFlagName, completion.AutocompleteDefault)
+
+	signPassphraseFileFlagName := "sign-passphrase-file"
+	flags.StringVar(&manifestPushOpts.SignPassphraseFileCLI, signPassphraseFileFlagName, "", "Read a passphrase for signing an image from `PATH`")
+	_ = pushCmd.RegisterFlagCompletionFunc(signPassphraseFileFlagName, completion.AutocompleteDefault)
+
 	flags.BoolVar(&manifestPushOpts.TLSVerifyCLI, "tls-verify", true, "require HTTPS and verify certificates when accessing the registry")
 	flags.BoolVarP(&manifestPushOpts.Quiet, "quiet", "q", false, "don't output progress information when pushing lists")
 	flags.SetNormalizeFunc(utils.AliasFlags)
@@ -79,6 +88,8 @@ func init() {
 	if registry.IsRemote() {
 		_ = flags.MarkHidden("cert-dir")
 		_ = flags.MarkHidden(signByFlagName)
+		_ = flags.MarkHidden(signBySigstorePrivateKeyFlagName)
+		_ = flags.MarkHidden(signPassphraseFileFlagName)
 	}
 }
 
@@ -104,6 +115,10 @@ func push(cmd *cobra.Command, args []string) error {
 		manifestPushOpts.Password = creds.Password
 	}
 
+	if err := common.PrepareSigningPassphrase(&manifestPushOpts.ImagePushOptions, manifestPushOpts.SignPassphraseFileCLI); err != nil {
+		return err
+	}
+
 	// TLS verification in c/image is controlled via a `types.OptionalBool`
 	// which allows for distinguishing among set-true, set-false, unspecified
 	// which is important to implement a sane way of dealing with defaults of