[Backport 5.2] sec: Make GraphQL cost limits configurable

CHANGELOG.md

@@ -44,6 +44,7 @@ All notable changes to Sourcegraph are documented in this file.
 
 - Added a new authorization configuration options to GitLab code host connections: "markInternalReposAsPublic". Setting "markInternalReposAsPublic" to true is useful for organizations that have a large amount of internal repositories that everyone on the instance should be able to access, removing the need to have permissions to access these repositories. Additionally, when configuring a GitLab auth provider, you can specify "syncInternalRepoPermissions": false, which will remove the need to sync permissions for these internal repositories. [#57858](https://github.com/sourcegraph/sourcegraph/pull/57858)
 - Experimental support for OpenAI powered autocomplete has been added. [#57872](https://github.com/sourcegraph/sourcegraph/pull/57872)
+- Added configurable GraphQL query cost limitations to prevent unintended resource exhaustion. Default values are now provided and enforced, replacing the previously unlimited behaviour. For more information, please refer to: [GraphQL Cost Limits Documentation](https://docs.sourcegraph.com/api/graphql#cost-limits). See details at [#58346](https://github.com/sourcegraph/sourcegraph/pull/58346).
 
 ### Changed
 

cmd/frontend/graphqlbackend/graphqlbackend.go

@@ -634,7 +634,7 @@ func NewSchema(
 	opts := []graphql.SchemaOpt{
 		graphql.Tracer(newRequestTracer(logger, db)),
 		graphql.UseStringDescriptions(),
-		graphql.MaxDepth(maxDepth),
+		graphql.MaxDepth(conf.RateLimits().GraphQLMaxDepth),
 	}
 	opts = append(opts, graphqlOpts...)
 	return graphql.ParseSchema(

cmd/frontend/graphqlbackend/rate_limit.go

@@ -22,10 +22,6 @@ import (
 // the algorithm
 const costEstimateVersion = 2
 
-const MaxAliasCount = 500        // SECURITY: prevent too many aliased queries
-const MaxFieldCount = 500 * 1000 // SECURITY: prevent deeply nested or overly broad queries
-const maxDepth = 30              // SECURITY: prevent deep queries that consume too many resources
-
 type QueryCost struct {
 	FieldCount int
 	MaxDepth   int

cmd/frontend/graphqlbackend/search_test.go

@@ -122,7 +122,7 @@ func TestSearch(t *testing.T) {
 			sr := newSchemaResolver(db, gsClient)
 			gqlSchema, err := graphql.ParseSchema(mainSchema, sr,
 				graphql.Tracer(newRequestTracer(logtest.Scoped(t), db)),
-				graphql.MaxDepth(maxDepth))
+				graphql.MaxDepth(conf.RateLimits().GraphQLMaxDepth))
 			if err != nil {
 				t.Fatal(err)
 			}

cmd/frontend/graphqlbackend/testing.go

@@ -15,6 +15,7 @@ import (
 	gqlerrors "github.com/graph-gophers/graphql-go/errors"
 	"github.com/stretchr/testify/require"
 
+	"github.com/sourcegraph/sourcegraph/internal/conf"
 	"github.com/sourcegraph/sourcegraph/internal/database"
 	"github.com/sourcegraph/sourcegraph/internal/gitserver"
 )
@@ -31,7 +32,7 @@ func mustParseGraphQLSchemaWithClient(t *testing.T, db database.DB, gitserverCli
 		gitserverClient,
 		[]OptionalResolver{},
 		graphql.PanicHandler(printStackTrace{&gqlerrors.DefaultPanicHandler{}}),
-		graphql.MaxDepth(maxDepth),
+		graphql.MaxDepth(conf.RateLimits().GraphQLMaxDepth),
 	)
 	if parseSchemaErr != nil {
 		t.Fatal(parseSchemaErr)

cmd/frontend/internal/httpapi/graphql.go

@@ -102,11 +102,13 @@ func serveGraphQL(logger log.Logger, schema *graphql.Schema, rlw graphqlbackend.
 			} else if cost != nil {
 				traceData.cost = cost
 
-				if !isInternal && (cost.AliasCount > graphqlbackend.MaxAliasCount) {
+				rl := conf.RateLimits()
+
+				if !isInternal && (cost.AliasCount > rl.GraphQLMaxAliases) {
 					return writeViolationError(w, "query exceeds maximum query cost")
 				}
 
-				if !isInternal && (cost.FieldCount > graphqlbackend.MaxFieldCount) {
+				if !isInternal && (cost.FieldCount > rl.GraphQLMaxFieldCount) {
 					return writeViolationError(w, "query exceeds maximum query cost")
 				}
 

internal/conf/computed.go

@@ -450,6 +450,29 @@ func PasswordPolicyEnabled() bool {
 	return pc.Enabled
 }
 
+func RateLimits() schema.RateLimits {
+	rl := schema.RateLimits{
+		GraphQLMaxAliases:    500,
+		GraphQLMaxFieldCount: 500_000,
+		GraphQLMaxDepth:      30,
+	}
+
+	configured := Get().RateLimits
+
+	if configured != nil {
+		if configured.GraphQLMaxAliases <= 0 {
+			rl.GraphQLMaxAliases = configured.GraphQLMaxAliases
+		}
+		if configured.GraphQLMaxFieldCount <= 0 {
+			rl.GraphQLMaxFieldCount = configured.GraphQLMaxFieldCount
+		}
+		if configured.GraphQLMaxDepth <= 0 {
+			rl.GraphQLMaxDepth = configured.GraphQLMaxDepth
+		}
+	}
+	return rl
+}
+
 // By default, password reset links are valid for 4 hours.
 const defaultPasswordLinkExpiry = 14400
 

schema/site.schema.json

@@ -49,6 +49,27 @@
       "type": "boolean",
       "default": false
     },
+    "rateLimits": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "graphQLMaxDepth": {
+          "description": "Maximum depth of nested objects allowed for GraphQL queries. Changes to this setting require a restart.",
+          "type": "integer",
+          "default": 30
+        },
+        "graphQLMaxAliases": {
+          "description": "Maximum number of aliases allowed in a GraphQL query",
+          "type": "integer",
+          "default": 500
+        },
+        "graphQLMaxFieldCount": {
+          "description": "Maximum number of estimated fields allowed in a GraphQL response",
+          "type": "integer",
+          "default": 500000
+        }
+      }
+    },
     "exportUsageTelemetry": {
       "type": "object",
       "additionalProperties": false,