google/internal/externalaccount: Removed URL validation for google URLs in ADC files

Removes URL validation for token_url, service_account_impersonation_url to allow for TPC urls and adds line to the docs to warn users. See https://github.com/googleapis/google-auth-library-nodejs/pull/1517 for same change in node.js library.

Change-Id: I85fa67ee0b99deed2adb75668a1b5501851c499c
GitHub-Last-Rev: 15d7759884
GitHub-Pull-Request: golang/oauth2#627
Reviewed-on: https://go-review.googlesource.com/c/oauth2/+/465696
Reviewed-by: Cody Oss <codyoss@google.com>
Run-TryBot: Cody Oss <codyoss@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Leo Siracusa <leosiracusa@google.com>

google/doc.go

@@ -57,6 +57,11 @@
 // executable-sourced credentials), please check out:
 // https://cloud.google.com/iam/docs/using-workload-identity-federation#oidc
 //
+// Note that this library does not perform any validation on the token_url, token_info_url,
+// or service_account_impersonation_url fields of the credential configuration.
+// It is not recommended to use a credential configuration that you did not generate with
+// the gcloud CLI unless you verify that the URL fields point to a googleapis.com domain.
+//
 // # Credentials
 //
 // The Credentials type represents Google credentials, including Application Default
@@ -81,4 +86,5 @@
 // same as the one obtained from the oauth2.Config returned from ConfigFromJSON or
 // JWTConfigFromJSON, but the Credentials may contain additional information
 // that is useful is some circumstances.
+//
 package google // import "golang.org/x/oauth2/google"

google/internal/externalaccount/basecredentials.go

@@ -67,22 +67,6 @@ type Config struct {
 // that include all elements in a given list, in that order.
 
 var (
-	validTokenURLPatterns = []*regexp.Regexp{
-		// The complicated part in the middle matches any number of characters that
-		// aren't period, spaces, or slashes.
-		regexp.MustCompile(`(?i)^[^\.\s\/\\]+\.sts\.googleapis\.com$`),
-		regexp.MustCompile(`(?i)^sts\.googleapis\.com$`),
-		regexp.MustCompile(`(?i)^sts\.[^\.\s\/\\]+\.googleapis\.com$`),
-		regexp.MustCompile(`(?i)^[^\.\s\/\\]+-sts\.googleapis\.com$`),
-		regexp.MustCompile(`(?i)^sts-[^\.\s\/\\]+\.p\.googleapis\.com$`),
-	}
-	validImpersonateURLPatterns = []*regexp.Regexp{
-		regexp.MustCompile(`^[^\.\s\/\\]+\.iamcredentials\.googleapis\.com$`),
-		regexp.MustCompile(`^iamcredentials\.googleapis\.com$`),
-		regexp.MustCompile(`^iamcredentials\.[^\.\s\/\\]+\.googleapis\.com$`),
-		regexp.MustCompile(`^[^\.\s\/\\]+-iamcredentials\.googleapis\.com$`),
-		regexp.MustCompile(`^iamcredentials-[^\.\s\/\\]+\.p\.googleapis\.com$`),
-	}
 	validWorkforceAudiencePattern *regexp.Regexp = regexp.MustCompile(`//iam\.googleapis\.com/locations/[^/]+/workforcePools/`)
 )
 
@@ -110,25 +94,13 @@ func validateWorkforceAudience(input string) bool {
 
 // TokenSource Returns an external account TokenSource struct. This is to be called by package google to construct a google.Credentials.
 func (c *Config) TokenSource(ctx context.Context) (oauth2.TokenSource, error) {
-	return c.tokenSource(ctx, validTokenURLPatterns, validImpersonateURLPatterns, "https")
+	return c.tokenSource(ctx, "https")
 }
 
 // tokenSource is a private function that's directly called by some of the tests,
 // because the unit test URLs are mocked, and would otherwise fail the
 // validity check.
-func (c *Config) tokenSource(ctx context.Context, tokenURLValidPats []*regexp.Regexp, impersonateURLValidPats []*regexp.Regexp, scheme string) (oauth2.TokenSource, error) {
-	valid := validateURL(c.TokenURL, tokenURLValidPats, scheme)
-	if !valid {
-		return nil, fmt.Errorf("oauth2/google: invalid TokenURL provided while constructing tokenSource")
-	}
-
-	if c.ServiceAccountImpersonationURL != "" {
-		valid := validateURL(c.ServiceAccountImpersonationURL, impersonateURLValidPats, scheme)
-		if !valid {
-			return nil, fmt.Errorf("oauth2/google: invalid ServiceAccountImpersonationURL provided while constructing tokenSource")
-		}
-	}
-
+func (c *Config) tokenSource(ctx context.Context, scheme string) (oauth2.TokenSource, error) {
 	if c.WorkforcePoolUserProject != "" {
 		valid := validateWorkforceAudience(c.Audience)
 		if !valid {

google/internal/externalaccount/basecredentials_test.go

@@ -9,7 +9,6 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
-	"strings"
 	"testing"
 	"time"
 
@@ -208,140 +207,6 @@ func TestNonworkforceWithWorkforcePoolUserProject(t *testing.T) {
 	}
 }
 
-func TestValidateURLTokenURL(t *testing.T) {
-	var urlValidityTests = []struct {
-		tokURL        string
-		expectSuccess bool
-	}{
-		{"https://east.sts.googleapis.com", true},
-		{"https://sts.googleapis.com", true},
-		{"https://sts.asfeasfesef.googleapis.com", true},
-		{"https://us-east-1-sts.googleapis.com", true},
-		{"https://sts.googleapis.com/your/path/here", true},
-		{"https://.sts.googleapis.com", false},
-		{"https://badsts.googleapis.com", false},
-		{"https://sts.asfe.asfesef.googleapis.com", false},
-		{"https://sts..googleapis.com", false},
-		{"https://-sts.googleapis.com", false},
-		{"https://us-ea.st-1-sts.googleapis.com", false},
-		{"https://sts.googleapis.com.evil.com/whatever/path", false},
-		{"https://us-eas\\t-1.sts.googleapis.com", false},
-		{"https:/us-ea/st-1.sts.googleapis.com", false},
-		{"https:/us-east 1.sts.googleapis.com", false},
-		{"https://", false},
-		{"http://us-east-1.sts.googleapis.com", false},
-		{"https://us-east-1.sts.googleapis.comevil.com", false},
-		{"https://sts-xyz.p.googleapis.com", true},
-		{"https://sts.pgoogleapis.com", false},
-		{"https://p.googleapis.com", false},
-		{"https://sts.p.com", false},
-		{"http://sts.p.googleapis.com", false},
-		{"https://xyz-sts.p.googleapis.com", false},
-		{"https://sts-xyz.123.p.googleapis.com", false},
-		{"https://sts-xyz.p1.googleapis.com", false},
-		{"https://sts-xyz.p.foo.com", false},
-		{"https://sts-xyz.p.foo.googleapis.com", false},
-	}
-	ctx := context.Background()
-	for _, tt := range urlValidityTests {
-		t.Run(" "+tt.tokURL, func(t *testing.T) { // We prepend a space ahead of the test input when outputting for sake of readability.
-			config := testConfig
-			config.TokenURL = tt.tokURL
-			_, err := config.TokenSource(ctx)
-
-			if tt.expectSuccess && err != nil {
-				t.Errorf("got %v but want nil", err)
-			} else if !tt.expectSuccess && err == nil {
-				t.Errorf("got nil but expected an error")
-			}
-		})
-	}
-	for _, el := range urlValidityTests {
-		el.tokURL = strings.ToUpper(el.tokURL)
-	}
-	for _, tt := range urlValidityTests {
-		t.Run(" "+tt.tokURL, func(t *testing.T) { // We prepend a space ahead of the test input when outputting for sake of readability.
-			config := testConfig
-			config.TokenURL = tt.tokURL
-			_, err := config.TokenSource(ctx)
-
-			if tt.expectSuccess && err != nil {
-				t.Errorf("got %v but want nil", err)
-			} else if !tt.expectSuccess && err == nil {
-				t.Errorf("got nil but expected an error")
-			}
-		})
-	}
-}
-
-func TestValidateURLImpersonateURL(t *testing.T) {
-	var urlValidityTests = []struct {
-		impURL        string
-		expectSuccess bool
-	}{
-		{"https://east.iamcredentials.googleapis.com", true},
-		{"https://iamcredentials.googleapis.com", true},
-		{"https://iamcredentials.asfeasfesef.googleapis.com", true},
-		{"https://us-east-1-iamcredentials.googleapis.com", true},
-		{"https://iamcredentials.googleapis.com/your/path/here", true},
-		{"https://.iamcredentials.googleapis.com", false},
-		{"https://badiamcredentials.googleapis.com", false},
-		{"https://iamcredentials.asfe.asfesef.googleapis.com", false},
-		{"https://iamcredentials..googleapis.com", false},
-		{"https://-iamcredentials.googleapis.com", false},
-		{"https://us-ea.st-1-iamcredentials.googleapis.com", false},
-		{"https://iamcredentials.googleapis.com.evil.com/whatever/path", false},
-		{"https://us-eas\\t-1.iamcredentials.googleapis.com", false},
-		{"https:/us-ea/st-1.iamcredentials.googleapis.com", false},
-		{"https:/us-east 1.iamcredentials.googleapis.com", false},
-		{"https://", false},
-		{"http://us-east-1.iamcredentials.googleapis.com", false},
-		{"https://us-east-1.iamcredentials.googleapis.comevil.com", false},
-		{"https://iamcredentials-xyz.p.googleapis.com", true},
-		{"https://iamcredentials.pgoogleapis.com", false},
-		{"https://p.googleapis.com", false},
-		{"https://iamcredentials.p.com", false},
-		{"http://iamcredentials.p.googleapis.com", false},
-		{"https://xyz-iamcredentials.p.googleapis.com", false},
-		{"https://iamcredentials-xyz.123.p.googleapis.com", false},
-		{"https://iamcredentials-xyz.p1.googleapis.com", false},
-		{"https://iamcredentials-xyz.p.foo.com", false},
-		{"https://iamcredentials-xyz.p.foo.googleapis.com", false},
-	}
-	ctx := context.Background()
-	for _, tt := range urlValidityTests {
-		t.Run(" "+tt.impURL, func(t *testing.T) { // We prepend a space ahead of the test input when outputting for sake of readability.
-			config := testConfig
-			config.TokenURL = "https://sts.googleapis.com" // Setting the most basic acceptable tokenURL
-			config.ServiceAccountImpersonationURL = tt.impURL
-			_, err := config.TokenSource(ctx)
-
-			if tt.expectSuccess && err != nil {
-				t.Errorf("got %v but want nil", err)
-			} else if !tt.expectSuccess && err == nil {
-				t.Errorf("got nil but expected an error")
-			}
-		})
-	}
-	for _, el := range urlValidityTests {
-		el.impURL = strings.ToUpper(el.impURL)
-	}
-	for _, tt := range urlValidityTests {
-		t.Run(" "+tt.impURL, func(t *testing.T) { // We prepend a space ahead of the test input when outputting for sake of readability.
-			config := testConfig
-			config.TokenURL = "https://sts.googleapis.com" // Setting the most basic acceptable tokenURL
-			config.ServiceAccountImpersonationURL = tt.impURL
-			_, err := config.TokenSource(ctx)
-
-			if tt.expectSuccess && err != nil {
-				t.Errorf("got %v but want nil", err)
-			} else if !tt.expectSuccess && err == nil {
-				t.Errorf("got nil but expected an error")
-			}
-		})
-	}
-}
-
 func TestWorkforcePoolCreation(t *testing.T) {
 	var audienceValidatyTests = []struct {
 		audience      string

google/internal/externalaccount/impersonate_test.go

@@ -9,7 +9,6 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
-	"regexp"
 	"testing"
 )
 
@@ -114,8 +113,7 @@ func TestImpersonation(t *testing.T) {
 			defer targetServer.Close()
 			testImpersonateConfig.TokenURL = targetServer.URL
 
-			allURLs := regexp.MustCompile(".+")
-			ourTS, err := testImpersonateConfig.tokenSource(context.Background(), []*regexp.Regexp{allURLs}, []*regexp.Regexp{allURLs}, "http")
+			ourTS, err := testImpersonateConfig.tokenSource(context.Background(), "http")
 			if err != nil {
 				t.Fatalf("Failed to create TokenSource: %v", err)
 			}