Add support for sigstoreSigned in (podman image trust set)

NOTE: This does not edit the use-sigstore-attachments value
in registries.d, similarly to how (podman image trust set) didn't
set the lookaside paths for simple signing.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

cmd/podman/images/trust_set.go

@@ -53,7 +53,7 @@ File(s) must exist before using this command`)
 }
 
 func setTrust(cmd *cobra.Command, args []string) error {
-	validTrustTypes := []string{"accept", "insecureAcceptAnything", "reject", "signedBy"}
+	validTrustTypes := []string{"accept", "insecureAcceptAnything", "reject", "signedBy", "sigstoreSigned"}
 
 	valid, err := isValidImageURI(args[0])
 	if err != nil || !valid {
@@ -61,7 +61,7 @@ func setTrust(cmd *cobra.Command, args []string) error {
 	}
 
 	if !util.StringInSlice(setOptions.Type, validTrustTypes) {
-		return fmt.Errorf("invalid choice: %s (choose from 'accept', 'reject', 'signedBy')", setOptions.Type)
+		return fmt.Errorf("invalid choice: %s (choose from 'accept', 'reject', 'signedBy', 'sigstoreSigned')", setOptions.Type)
 	}
 	return registry.ImageEngine().SetTrust(registry.Context(), args, setOptions)
 }

docs/source/markdown/podman-image-trust.1.md

@@ -32,7 +32,8 @@ Trust **type** provides a way to:
 
 Allowlist ("accept") or
 Denylist ("reject") registries or
-Require signature (“signedBy”).
+Require a simple signing signature (“signedBy”),
+Require a sigstore signature ("sigstoreSigned").
 
 Trust may be updated using the command **podman image trust set** for an existing trust scope.
 
@@ -45,12 +46,14 @@ Trust may be updated using the command **podman image trust set** for an existin
 #### **--pubkeysfile**, **-f**=*KEY1*
   A path to an exported public key on the local system. Key paths
   will be referenced in policy.json. Any path to a file may be used but locating the file in **/etc/pki/containers** is recommended. Options may be used multiple times to
-  require an image be signed by multiple keys.  The **--pubkeysfile** option is required for the **signedBy** type.
+  require an image be signed by multiple keys.  The **--pubkeysfile** option is required for the **signedBy** and **sigstoreSigned** types.
 
 #### **--type**, **-t**=*value*
   The trust type for this policy entry.
   Accepted values:
-    **signedBy** (default): Require signatures with corresponding list of
+    **signedBy** (default): Require simple signing signatures with corresponding list of
+                        public keys
+    **sigstoreSigned**: Require sigstore signatures with corresponding list of
                         public keys
     **accept**: do not require any signatures for this
             registry scope

pkg/trust/policy.go

@@ -161,6 +161,14 @@ func AddPolicyEntries(policyPath string, input AddPolicyEntriesInput) error {
 			newReposContent = append(newReposContent, RepoContent{Type: trustType, KeyType: "GPGKeys", KeyPath: filepath})
 		}
 
+	case "sigstoreSigned":
+		if len(pubkeysfile) == 0 {
+			return errors.New("at least one public key must be defined for type 'sigstoreSigned'")
+		}
+		for _, filepath := range pubkeysfile {
+			newReposContent = append(newReposContent, RepoContent{Type: trustType, KeyPath: filepath})
+		}
+
 	default:
 		return fmt.Errorf("unknown trust type %q", input.Type)
 	}

pkg/trust/policy_test.go

@@ -47,6 +47,11 @@ func TestAddPolicyEntries(t *testing.T) {
 			Type:        "signedBy",
 			PubKeyFiles: []string{}, // A key is missing
 		},
+		{
+			Scope:       "default",
+			Type:        "sigstoreSigned",
+			PubKeyFiles: []string{}, // A key is missing
+		},
 		{
 			Scope:       "default",
 			Type:        "this-is-unknown",
@@ -73,6 +78,12 @@ func TestAddPolicyEntries(t *testing.T) {
 		PubKeyFiles: []string{"/1.pub", "/2.pub"},
 	})
 	assert.NoError(t, err)
+	err = AddPolicyEntries(policyPath, AddPolicyEntriesInput{
+		Scope:       "quay.io/sigstore-signed",
+		Type:        "sigstoreSigned",
+		PubKeyFiles: []string{"/1.pub", "/2.pub"},
+	})
+	assert.NoError(t, err)
 
 	// Test that the outcome is consumable, and compare it with the expected values.
 	parsedPolicy, err := signature.NewPolicyFromFile(policyPath)
@@ -90,6 +101,10 @@ func TestAddPolicyEntries(t *testing.T) {
 					xNewPRSignedByKeyPath(t, "/1.pub", signature.NewPRMMatchRepoDigestOrExact()),
 					xNewPRSignedByKeyPath(t, "/2.pub", signature.NewPRMMatchRepoDigestOrExact()),
 				},
+				"quay.io/sigstore-signed": {
+					xNewPRSigstoreSignedKeyPath(t, "/1.pub", signature.NewPRMMatchRepoDigestOrExact()),
+					xNewPRSigstoreSignedKeyPath(t, "/2.pub", signature.NewPRMMatchRepoDigestOrExact()),
+				},
 			},
 		},
 	}, parsedPolicy)
@@ -101,3 +116,10 @@ func xNewPRSignedByKeyPath(t *testing.T, keyPath string, signedIdentity signatur
 	require.NoError(t, err)
 	return pr
 }
+
+// xNewPRSigstoreSignedKeyPath is a wrapper for NewPRSigstoreSignedKeyPath which must not fail.
+func xNewPRSigstoreSignedKeyPath(t *testing.T, keyPath string, signedIdentity signature.PolicyReferenceMatch) signature.PolicyRequirement {
+	pr, err := signature.NewPRSigstoreSignedKeyPath(keyPath, signedIdentity)
+	require.NoError(t, err)
+	return pr
+}