Upgrade to TUF v2 client

Swap the use of the go-tuf v0.7.0 client from sigstore/sigstore to the
v2.0.0 client from sigstore/sigstore-go. Sigstore-go provides a way to
check for a trusted root and automatically use it if available, but can
also fetch individual targets as needed if the provided TUF mirror does
not supply a trusted_root.json.

This change is intended to be backwards compatible and transparent.

TODO:
- e2e tests
- deprecate `cosign initialize`

Signed-off-by: Colleen Murphy <colleenmurphy@google.com>

cmd/cosign/cli/fulcio/fulcioverifier/fulcioverifier.go

@@ -33,7 +33,7 @@ func NewSigner(ctx context.Context, ko options.KeyOpts, signer signature.SignerV
 	}
 
 	// Grab the PublicKeys for the CTFE, either from tuf or env.
-	pubKeys, err := cosign.GetCTLogPubs(ctx)
+	pubKeys, err := cosign.GetCTLogPubs()
 	if err != nil {
 		return nil, fmt.Errorf("getting CTFE public keys: %w", err)
 	}

cmd/cosign/cli/sign/sign.go

@@ -505,7 +505,7 @@ func signerFromKeyRef(ctx context.Context, certPath, certChainPath, keyRef strin
 		return nil, err
 	}
 	if contains {
-		pubKeys, err := cosign.GetCTLogPubs(ctx)
+		pubKeys, err := cosign.GetCTLogPubs()
 		if err != nil {
 			return nil, fmt.Errorf("getting CTLog public keys: %w", err)
 		}

cmd/cosign/cli/verify/verify.go

@@ -88,7 +88,7 @@ func (c *VerifyCommand) loadTSACertificates(ctx context.Context) (*cosign.TSACer
 	if c.TSACertChainPath == "" && !c.UseSignedTimestamps {
 		return nil, fmt.Errorf("TSA certificate chain path not provided and use-signed-timestamps not set")
 	}
-	tsaCertificates, err := cosign.GetTSACerts(ctx, c.TSACertChainPath, cosign.GetTufTargets)
+	tsaCertificates, err := cosign.GetTSACerts(c.TSACertChainPath)
 	if err != nil {
 		return nil, fmt.Errorf("unable to load TSA certificates: %w", err)
 	}
@@ -169,7 +169,7 @@ func (c *VerifyCommand) Exec(ctx context.Context, images []string) (err error) {
 		}
 		// This performs an online fetch of the Rekor public keys, but this is needed
 		// for verifying tlog entries (both online and offline).
-		co.RekorPubKeys, err = cosign.GetRekorPubs(ctx)
+		co.RekorPubKeys, err = cosign.GetRekorPubs()
 		if err != nil {
 			return fmt.Errorf("getting Rekor public keys: %w", err)
 		}
@@ -185,7 +185,7 @@ func (c *VerifyCommand) Exec(ctx context.Context, images []string) (err error) {
 
 	// Ignore Signed Certificate Timestamp if the flag is set or a key is provided
 	if shouldVerifySCT(c.IgnoreSCT, c.KeyRef, c.Sk) {
-		co.CTLogPubKeys, err = cosign.GetCTLogPubs(ctx)
+		co.CTLogPubKeys, err = cosign.GetCTLogPubs()
 		if err != nil {
 			return fmt.Errorf("getting ctlog public keys: %w", err)
 		}

cmd/cosign/cli/verify/verify_attestation.go

@@ -76,7 +76,7 @@ func (c *VerifyAttestationCommand) loadTSACertificates(ctx context.Context) (*co
 	if c.TSACertChainPath == "" && !c.UseSignedTimestamps {
 		return nil, fmt.Errorf("TSA certificate chain path not provided and use-signed-timestamps not set")
 	}
-	tsaCertificates, err := cosign.GetTSACerts(ctx, c.TSACertChainPath, cosign.GetTufTargets)
+	tsaCertificates, err := cosign.GetTSACerts(c.TSACertChainPath)
 	if err != nil {
 		return nil, fmt.Errorf("unable to load TSA certificates: %w", err)
 	}
@@ -125,7 +125,7 @@ func (c *VerifyAttestationCommand) Exec(ctx context.Context, images []string) (e
 	}
 	// Ignore Signed Certificate Timestamp if the flag is set or a key is provided
 	if shouldVerifySCT(c.IgnoreSCT, c.KeyRef, c.Sk) {
-		co.CTLogPubKeys, err = cosign.GetCTLogPubs(ctx)
+		co.CTLogPubKeys, err = cosign.GetCTLogPubs()
 		if err != nil {
 			return fmt.Errorf("getting ctlog public keys: %w", err)
 		}
@@ -151,7 +151,7 @@ func (c *VerifyAttestationCommand) Exec(ctx context.Context, images []string) (e
 		}
 		// This performs an online fetch of the Rekor public keys, but this is needed
 		// for verifying tlog entries (both online and offline).
-		co.RekorPubKeys, err = cosign.GetRekorPubs(ctx)
+		co.RekorPubKeys, err = cosign.GetRekorPubs()
 		if err != nil {
 			return fmt.Errorf("getting Rekor public keys: %w", err)
 		}

cmd/cosign/cli/verify/verify_blob.go

@@ -73,7 +73,7 @@ func (c *VerifyBlobCmd) loadTSACertificates(ctx context.Context) (*cosign.TSACer
 	if c.TSACertChainPath == "" && !c.UseSignedTimestamps {
 		return nil, fmt.Errorf("either TSA certificate chain path must be provided or use-signed-timestamps must be set")
 	}
-	tsaCertificates, err := cosign.GetTSACerts(ctx, c.TSACertChainPath, cosign.GetTufTargets)
+	tsaCertificates, err := cosign.GetTSACerts(c.TSACertChainPath)
 	if err != nil {
 		return nil, fmt.Errorf("unable to load TSA certificates: %w", err)
 	}
@@ -161,7 +161,7 @@ func (c *VerifyBlobCmd) Exec(ctx context.Context, blobRef string) error {
 		}
 		// This performs an online fetch of the Rekor public keys, but this is needed
 		// for verifying tlog entries (both online and offline).
-		co.RekorPubKeys, err = cosign.GetRekorPubs(ctx)
+		co.RekorPubKeys, err = cosign.GetRekorPubs()
 		if err != nil {
 			return fmt.Errorf("getting Rekor public keys: %w", err)
 		}
@@ -294,7 +294,7 @@ func (c *VerifyBlobCmd) Exec(ctx context.Context, blobRef string) error {
 
 	// Ignore Signed Certificate Timestamp if the flag is set or a key is provided
 	if shouldVerifySCT(c.IgnoreSCT, c.KeyRef, c.Sk) {
-		co.CTLogPubKeys, err = cosign.GetCTLogPubs(ctx)
+		co.CTLogPubKeys, err = cosign.GetCTLogPubs()
 		if err != nil {
 			return fmt.Errorf("getting ctlog public keys: %w", err)
 		}

cmd/cosign/cli/verify/verify_blob_attestation.go

@@ -160,7 +160,7 @@ func (c *VerifyBlobAttestationCommand) Exec(ctx context.Context, artifactPath st
 	}
 
 	if c.TSACertChainPath != "" || c.UseSignedTimestamps {
-		tsaCertificates, err := cosign.GetTSACerts(ctx, c.TSACertChainPath, cosign.GetTufTargets)
+		tsaCertificates, err := cosign.GetTSACerts(c.TSACertChainPath)
 		if err != nil {
 			return fmt.Errorf("unable to load or get TSA certificates: %w", err)
 		}
@@ -179,7 +179,7 @@ func (c *VerifyBlobAttestationCommand) Exec(ctx context.Context, artifactPath st
 		}
 		// This performs an online fetch of the Rekor public keys, but this is needed
 		// for verifying tlog entries (both online and offline).
-		co.RekorPubKeys, err = cosign.GetRekorPubs(ctx)
+		co.RekorPubKeys, err = cosign.GetRekorPubs()
 		if err != nil {
 			return fmt.Errorf("getting Rekor public keys: %w", err)
 		}
@@ -192,7 +192,7 @@ func (c *VerifyBlobAttestationCommand) Exec(ctx context.Context, artifactPath st
 
 	// Ignore Signed Certificate Timestamp if the flag is set or a key is provided
 	if shouldVerifySCT(c.IgnoreSCT, c.KeyRef, c.Sk) {
-		co.CTLogPubKeys, err = cosign.GetCTLogPubs(ctx)
+		co.CTLogPubKeys, err = cosign.GetCTLogPubs()
 		if err != nil {
 			return fmt.Errorf("getting ctlog public keys: %w", err)
 		}

internal/pkg/cosign/fulcio/fulcioroots/fulcioroots.go

@@ -16,15 +16,10 @@
 package fulcioroots
 
 import (
-	"bytes"
 	"crypto/x509"
-	"fmt"
-	"os"
 	"sync"
 
-	"github.com/sigstore/cosign/v2/pkg/cosign/env"
-	"github.com/sigstore/sigstore/pkg/cryptoutils"
-	"github.com/sigstore/sigstore/pkg/fulcioroots"
+	"github.com/sigstore/cosign/v2/pkg/cosign"
 )
 
 var (
@@ -64,41 +59,5 @@ func ReInit() error {
 }
 
 func initRoots() (*x509.CertPool, *x509.CertPool, error) {
-	rootPool := x509.NewCertPool()
-	// intermediatePool should be nil if no intermediates are found
-	var intermediatePool *x509.CertPool
-
-	rootEnv := env.Getenv(env.VariableSigstoreRootFile)
-	if rootEnv != "" {
-		raw, err := os.ReadFile(rootEnv)
-		if err != nil {
-			return nil, nil, fmt.Errorf("error reading root PEM file: %w", err)
-		}
-		certs, err := cryptoutils.UnmarshalCertificatesFromPEM(raw)
-		if err != nil {
-			return nil, nil, fmt.Errorf("error unmarshalling certificates: %w", err)
-		}
-		for _, cert := range certs {
-			// root certificates are self-signed
-			if bytes.Equal(cert.RawSubject, cert.RawIssuer) {
-				rootPool.AddCert(cert)
-			} else {
-				if intermediatePool == nil {
-					intermediatePool = x509.NewCertPool()
-				}
-				intermediatePool.AddCert(cert)
-			}
-		}
-	} else {
-		var err error
-		rootPool, err = fulcioroots.Get()
-		if err != nil {
-			return nil, nil, err
-		}
-		intermediatePool, err = fulcioroots.GetIntermediates()
-		if err != nil {
-			return nil, nil, err
-		}
-	}
-	return rootPool, intermediatePool, nil
+	return cosign.GetFulcioCerts()
 }

pkg/cosign/ctlog.go

@@ -15,13 +15,11 @@
 package cosign
 
 import (
-	"context"
 	"errors"
 	"fmt"
-	"os"
 
 	"github.com/sigstore/cosign/v2/pkg/cosign/env"
-	"github.com/sigstore/sigstore/pkg/tuf"
+	"github.com/sigstore/sigstore-go/pkg/root"
 )
 
 // This is the CT log public key target name
@@ -32,37 +30,36 @@ var ctPublicKeyStr = `ctfe.pub`
 // By default the public keys comes from TUF, but you can override this for test
 // purposes by using an env variable `SIGSTORE_CT_LOG_PUBLIC_KEY_FILE`. If using
 // an alternate, the file can be PEM, or DER format.
-func GetCTLogPubs(ctx context.Context) (*TrustedTransparencyLogPubKeys, error) {
+func GetCTLogPubs() (*TrustedTransparencyLogPubKeys, error) {
 	publicKeys := NewTrustedTransparencyLogPubKeys()
 	altCTLogPub := env.Getenv(env.VariableSigstoreCTLogPublicKeyFile)
 
 	if altCTLogPub != "" {
-		raw, err := os.ReadFile(altCTLogPub)
-		if err != nil {
-			return nil, fmt.Errorf("error reading alternate CTLog public key file: %w", err)
-		}
-		if err := publicKeys.AddTransparencyLogPubKey(raw, tuf.Active); err != nil {
-			return nil, fmt.Errorf("AddCTLogPubKey: %w", err)
-		}
-	} else {
-		tufClient, err := tuf.NewFromEnv(ctx)
-		if err != nil {
-			return nil, err
-		}
-		targets, err := tufClient.GetTargetsByMeta(tuf.CTFE, []string{ctPublicKeyStr})
-		if err != nil {
-			return nil, err
-		}
-		for _, t := range targets {
-			if err := publicKeys.AddTransparencyLogPubKey(t.Target, t.Status); err != nil {
-				return nil, fmt.Errorf("AddCTLogPubKey: %w", err)
-			}
+		return addKeyFromFile(&publicKeys, altCTLogPub, "CT log public key")
+	}
+
+	opts, err := setTUFOpts()
+	if err != nil {
+		return nil, err
+	}
+
+	// Try getting keys from trusted_root.json
+	trustedRoot, _ := root.NewLiveTrustedRoot(opts)
+	if trustedRoot == nil {
+		// The TUF repository didn't have a trusted_root.json, try getting the individual target
+		return addKeyFromTUF(&publicKeys, opts, ctPublicKeyStr, "CT log public key")
+	}
+
+	ctlogs := trustedRoot.CTLogs()
+	for _, ct := range ctlogs {
+		validity := checkValidityPeriod(ct.ValidityPeriodStart, ct.ValidityPeriodEnd)
+		if err := publicKeys.AddTransparencyLogPubKey(ct.PublicKey, validity); err != nil {
+			return nil, fmt.Errorf("error adding CT log public key: %w", err)
 		}
 	}
 
 	if len(publicKeys.Keys) == 0 {
 		return nil, errors.New("none of the CTLog public keys have been found")
 	}
-
 	return &publicKeys, nil
 }

pkg/cosign/ctlog_test.go

@@ -15,7 +15,6 @@
 package cosign
 
 import (
-	"context"
 	"os"
 	"testing"
 )
@@ -31,7 +30,7 @@ Nmo7M3bN7+dQddw9Ibc2R3SV8tzBZw0rST8FKcn4apJepcKM4qUpYUeNfw==
 )
 
 func TestGetCTLogPubKeys(t *testing.T) {
-	keys, err := GetCTLogPubs(context.Background())
+	keys, err := GetCTLogPubs()
 	if err != nil {
 		t.Fatalf("Unexpected error calling GetCTLogPubs, expected nil: %v", err)
 	}
@@ -61,7 +60,7 @@ func TestGetCTLogPubKeysAlt(t *testing.T) {
 	}
 	t.Setenv("SIGSTORE_CT_LOG_PUBLIC_KEY_FILE", pkFile.Name())
 
-	keys, err := GetCTLogPubs(context.Background())
+	keys, err := GetCTLogPubs()
 	if err != nil {
 		t.Errorf("Unexpected error calling GetCTLogPubs, expected nil: %v", err)
 	}