From 90dab43741ce8706a3faf3412d81478856be231f Mon Sep 17 00:00:00 2001
From: Joseph Schorr <josephschorr@users.noreply.github.com>
Date: Tue, 20 Feb 2024 14:47:34 -0500
Subject: [PATCH] Set maximum bulk check size

---
 internal/services/v1/errors.go       | 36 ++++++++++++++++++++++++++++
 internal/services/v1/experimental.go |  6 +++++
 2 files changed, 42 insertions(+)

diff --git a/internal/services/v1/errors.go b/internal/services/v1/errors.go
index a1f1333605..993d923bdd 100644
--- a/internal/services/v1/errors.go
+++ b/internal/services/v1/errors.go
@@ -15,6 +15,42 @@ import (
 	"github.com/authzed/spicedb/pkg/tuple"
 )
 
+// ErrExceedsMaximumChecks occurs when too many checks are given to a call.
+type ErrExceedsMaximumChecks struct {
+	error
+	checkCount      uint64
+	maxCountAllowed uint64
+}
+
+// MarshalZerologObject implements zerolog object marshalling.
+func (err ErrExceedsMaximumChecks) MarshalZerologObject(e *zerolog.Event) {
+	e.Err(err.error).Uint64("checkCount", err.checkCount).Uint64("maxCountAllowed", err.maxCountAllowed)
+}
+
+// GRPCStatus implements retrieving the gRPC status for the error.
+func (err ErrExceedsMaximumChecks) GRPCStatus() *status.Status {
+	return spiceerrors.WithCodeAndDetails(
+		err,
+		codes.InvalidArgument,
+		spiceerrors.ForReason(
+			v1.ErrorReason_ERROR_REASON_UNSPECIFIED,
+			map[string]string{
+				"check_count":            strconv.FormatUint(err.checkCount, 10),
+				"maximum_checks_allowed": strconv.FormatUint(err.maxCountAllowed, 10),
+			},
+		),
+	)
+}
+
+// NewExceedsMaximumChecksErr creates a new error representing that too many updates were given to a WriteRelationships call.
+func NewExceedsMaximumChecksErr(checkCount uint64, maxCountAllowed uint64) ErrExceedsMaximumChecks {
+	return ErrExceedsMaximumChecks{
+		error:           fmt.Errorf("check count of %d is greater than maximum allowed of %d", checkCount, maxCountAllowed),
+		checkCount:      checkCount,
+		maxCountAllowed: maxCountAllowed,
+	}
+}
+
 // ErrExceedsMaximumUpdates occurs when too many updates are given to a call.
 type ErrExceedsMaximumUpdates struct {
 	error
diff --git a/internal/services/v1/experimental.go b/internal/services/v1/experimental.go
index 4745d7de52..a98faf899f 100644
--- a/internal/services/v1/experimental.go
+++ b/internal/services/v1/experimental.go
@@ -410,12 +410,18 @@ func (es *experimentalServer) BulkExportRelationships(
 	return nil
 }
 
+const maxBulkCheckCount = 10000
+
 func (es *experimentalServer) BulkCheckPermission(ctx context.Context, req *v1.BulkCheckPermissionRequest) (*v1.BulkCheckPermissionResponse, error) {
 	atRevision, checkedAt, err := consistency.RevisionFromContext(ctx)
 	if err != nil {
 		return nil, es.rewriteError(ctx, err)
 	}
 
+	if len(req.Items) > maxBulkCheckCount {
+		return nil, es.rewriteError(ctx, NewExceedsMaximumChecksErr(uint64(len(req.Items)), maxBulkCheckCount))
+	}
+
 	// Compute a hash for each requested item and record its index(es) for the items, to be used for sorting of results.
 	itemCount, err := genutil.EnsureUInt32(len(req.Items))
 	if err != nil {