libimage: Fix getDockerAuthConfig() for authentication

- We need to set DockerAuthConfig even if we use of
non-IdentityToken credentials.

- This function should be failed when there are multiple
  credential sources, not only `Username` + `Credentials`.

Signed-off-by: Toshiki Sonoda <sonoda.toshiki@fujitsu.com>

common/libimage/copier.go

@@ -167,39 +167,37 @@ var storageAllowedPolicyScopes = signature.PolicyTransportScopes{
 	},
 }
 
-// getDockerAuthConfig extracts a docker auth config from the CopyOptions.  Returns
-// nil if no credentials are set.
-func (options *CopyOptions) getDockerAuthConfig() (*types.DockerAuthConfig, error) {
-	authConf := &types.DockerAuthConfig{IdentityToken: options.IdentityToken}
+// getDockerAuthConfig extracts a docker auth config. Returns nil if
+// no credentials are set.
+func getDockerAuthConfig(name, passwd, creds, idToken string) (*types.DockerAuthConfig, error) {
+	numCredsSources := 0
 
-	if options.Username != "" {
-		if options.Credentials != "" {
-			return nil, errors.New("username/password cannot be used with credentials")
+	if name != "" {
+		numCredsSources++
 	}
-		authConf.Username = options.Username
-		authConf.Password = options.Password
-		return authConf, nil
-	}
-
-	if options.Credentials != "" {
-		split := strings.SplitN(options.Credentials, ":", 2)
-		switch len(split) {
-		case 1:
-			authConf.Username = split[0]
-		default:
-			authConf.Username = split[0]
-			authConf.Password = split[1]
-		}
-		return authConf, nil
-	}
-
-	// We should return nil unless a token was set.  That's especially
-	// useful for Podman's remote API.
-	if options.IdentityToken != "" {
-		return authConf, nil
+	if creds != "" {
+		name, passwd, _ = strings.Cut(creds, ":")
+		numCredsSources++
+	}
+	if idToken != "" {
+		numCredsSources++
+	}
+	authConf := &types.DockerAuthConfig{
+		Username:      name,
+		Password:      passwd,
+		IdentityToken: idToken,
 	}
 
+	switch numCredsSources {
+	case 0:
+		// Return nil if there is no credential source.
 		return nil, nil
+	case 1:
+		return authConf, nil
+	default:
+		// Cannot use the multiple credential sources.
+		return nil, errors.New("cannot use the multiple credential sources")
+	}
 }
 
 // newCopier creates a copier.  Note that fields in options *may* overwrite the
@@ -237,7 +235,7 @@ func (r *Runtime) newCopier(options *CopyOptions) (*copier, error) {
 		c.systemContext.SignaturePolicyPath = options.SignaturePolicyPath
 	}
 
-	dockerAuthConfig, err := options.getDockerAuthConfig()
+	dockerAuthConfig, err := getDockerAuthConfig(options.Username, options.Password, options.Credentials, options.IdentityToken)
 	if err != nil {
 		return nil, err
 	}

common/libimage/search.go

@@ -2,7 +2,6 @@ package libimage
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -219,29 +218,12 @@ func (r *Runtime) searchImageInRegistry(ctx context.Context, term, registry stri
 		sys.DockerCertPath = options.CertDirPath
 	}
 
-	authConf := &types.DockerAuthConfig{IdentityToken: options.IdentityToken}
-	if options.Username != "" {
-		if options.Credentials != "" {
-			return nil, errors.New("username/password cannot be used with credentials")
+	dockerAuthConfig, err := getDockerAuthConfig(options.Username, options.Password, options.Credentials, options.IdentityToken)
+	if err != nil {
+		return nil, err
 	}
-		authConf.Username = options.Username
-		authConf.Password = options.Password
-	}
-
-	if options.Credentials != "" {
-		split := strings.SplitN(options.Credentials, ":", 2)
-		switch len(split) {
-		case 1:
-			authConf.Username = split[0]
-		default:
-			authConf.Username = split[0]
-			authConf.Password = split[1]
-		}
-	}
-	// We should set the authConf unless a token was set.  That's especially
-	// useful for Podman's remote API.
-	if options.IdentityToken != "" {
-		sys.DockerAuthConfig = authConf
+	if dockerAuthConfig != nil {
+		sys.DockerAuthConfig = dockerAuthConfig
 	}
 
 	if options.ListTags {