Team LBAC: Fix backend validation (#77612)

* Team LBAC: Fix backend validation

* more tests

* use slices.ContainsFunc()

pkg/api/datasources.go

@@ -11,8 +11,10 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/grafana/grafana-plugin-sdk-go/backend"
+	"github.com/prometheus/prometheus/promql/parser"
+	"golang.org/x/exp/slices"
 
+	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana/pkg/api/datasource"
 	"github.com/grafana/grafana/pkg/api/dtos"
 	"github.com/grafana/grafana/pkg/api/response"
@@ -336,10 +338,11 @@ func validateURL(cmdType string, url string) response.Response {
 // This is done to prevent data source proxy from being used to circumvent auth proxy.
 // For more context take a look at CVE-2022-35957
 func validateJSONData(ctx context.Context, jsonData *simplejson.Json, cfg *setting.Cfg, features *featuremgmt.FeatureManager) error {
-	if jsonData == nil || !cfg.AuthProxyEnabled {
+	if jsonData == nil {
 		return nil
 	}
 
+	if cfg.AuthProxyEnabled {
 		for key, value := range jsonData.MustMap() {
 			if strings.HasPrefix(key, datasources.CustomHeaderName) {
 				header := fmt.Sprint(value)
@@ -349,6 +352,7 @@ func validateJSONData(ctx context.Context, jsonData *simplejson.Json, cfg *setti
 				}
 			}
 		}
+	}
 
 	// Prevent adding a data source team header with a name that matches the auth proxy header name
 	if features.IsEnabled(featuremgmt.FlagTeamHttpHeaders) {
@@ -374,11 +378,13 @@ func validateTeamHTTPHeaderJSON(jsonData *simplejson.Json) error {
 	// each teams headers
 	for _, teamheaders := range teamHTTPHeadersJSON {
 		for _, header := range teamheaders {
-			if !contains(validHeaders, header.Header) {
+			if !slices.ContainsFunc(validHeaders, func(v string) bool {
+				return http.CanonicalHeaderKey(v) == http.CanonicalHeaderKey(header.Header)
+			}) {
 				datasourcesLogger.Error("Cannot add a data source team header that is different than", "headerName", header.Header)
 				return errors.New("validation error, invalid header name specified")
 			}
-			if !teamHTTPHeaderValueRegexMatch(header.Value) {
+			if !validateLBACHeader(header.Value) {
 				datasourcesLogger.Error("Cannot add a data source team header value with invalid value", "headerValue", header.Value)
 				return errors.New("validation error, invalid header value syntax")
 			}
@@ -387,27 +393,20 @@ func validateTeamHTTPHeaderJSON(jsonData *simplejson.Json) error {
 	return nil
 }
 
-func contains(slice []string, value string) bool {
+// validateLBACHeader returns true if the header value matches the syntax
-	for _, v := range slice {
+// 1234:{ name!="value",foo!~"bar" }
-		if http.CanonicalHeaderKey(v) == http.CanonicalHeaderKey(value) {
+func validateLBACHeader(headervalue string) bool {
-			return true
+	exp := `^\d+:(.+)`
-		}
+	pattern, err := regexp.Compile(exp)
-	}
-	return false
-}
-
-// teamHTTPHeaderValueRegexMatch returns true if the header value matches the regex
-// words separated by special characters
-// namespace!="auth", env="prod", env!~"dev"
-func teamHTTPHeaderValueRegexMatch(headervalue string) bool {
-	// link to regex: https://regex101.com/r/I8KhZz/1
-	// 1234:{ name!="value",foo!~"bar" }
-	exp := `^\d+:{(?:\s*\w+\s*(?:=|!=|=~|!~)\s*\"\w+\"\s*,*)+}$`
-	reg, err := regexp.Compile(exp)
 	if err != nil {
 		return false
 	}
-	return reg.Match([]byte(strings.TrimSpace(headervalue)))
+	match := pattern.FindSubmatch([]byte(strings.TrimSpace(headervalue)))
+	if match == nil || len(match) < 2 {
+		return false
+	}
+	_, err = parser.ParseMetricSelector(string(match[1]))
+	return err == nil
 }
 
 // swagger:route POST /datasources datasources addDataSource

pkg/api/datasources_test.go

@@ -481,18 +481,22 @@ func TestAPI_datasources_AccessControl(t *testing.T) {
 	}
 }
 
-// TeamHTTPHeaderValueRegexMatch returns a regex that can be used to check
+func TestValidateLBACHeader(t *testing.T) {
-func TestTeamHTTPHeaderValueRegexMatch(t *testing.T) {
 	testcases := []struct {
 		desc            string
 		teamHeaderValue string
 		want            bool
 	}{
 		{
-			desc:            "Should be valid regex match for team headervalue",
+			desc:            "Should allow valid header",
 			teamHeaderValue: `1234:{ name!="value",foo!~"bar" }`,
 			want:            true,
 		},
+		{
+			desc:            "Should allow valid selector",
+			teamHeaderValue: `1234:{ name!="value",foo!~"bar/baz.foo" }`,
+			want:            true,
+		},
 		{
 			desc:            "Should return false for incorrect header value",
 			teamHeaderValue: `1234:!="value",foo!~"bar" }`,
@@ -501,7 +505,7 @@ func TestTeamHTTPHeaderValueRegexMatch(t *testing.T) {
 	}
 	for _, tc := range testcases {
 		t.Run(tc.desc, func(t *testing.T) {
-			assert.Equal(t, tc.want, teamHTTPHeaderValueRegexMatch(tc.teamHeaderValue))
+			assert.Equal(t, tc.want, validateLBACHeader(tc.teamHeaderValue))
 		})
 	}
 }