fix(webapp): escape realtime tags filter to prevent SQL injection (#3739)

Author: Purvi09

.server-changes/fix-realtime-tags-sql-injection.md

@@ -0,0 +1,6 @@
+---
+area: webapp
+type: fix
+---
+
+Escape single quotes in user-supplied realtime `tags` filter to prevent SQL injection into the Electric `where` clause

apps/webapp/app/services/realtimeClient.server.ts

@@ -52,6 +52,11 @@ const DEFAULT_ELECTRIC_COLUMNS = [
 const RESERVED_COLUMNS = ["id", "taskIdentifier", "friendlyId", "status", "createdAt"];
 const RESERVED_SEARCH_PARAMS = ["createdAt", "tags", "skipColumns"];
 
+// Doubles single quotes so a value is safe inside a single-quoted SQL string literal.
+export function escapeSqlStringLiteral(value: string): string {
+  return value.replace(/'/g, "''");
+}
+
 export type RealtimeClientOptions = {
   electricOrigin: string | string[];
   redis: RedisWithClusterOptions;
@@ -171,7 +176,10 @@ export class RealtimeClient {
     const whereClauses: string[] = [`"runtimeEnvironmentId"='${environment.id}'`];
 
     if (params.tags) {
-      whereClauses.push(`"runTags" @> ARRAY[${params.tags.map((t) => `'${t}'`).join(",")}]`);
+      // Escape user-supplied tags so they can't break out of the SQL string literal.
+      whereClauses.push(
+        `"runTags" @> ARRAY[${params.tags.map((t) => `'${escapeSqlStringLiteral(t)}'`).join(",")}]`
+      );
     }
 
     const createdAtFilter = await this.#calculateCreatedAtFilter(url, params.createdAt);

apps/webapp/test/realtimeClientEscapeSqlStringLiteral.test.ts

@@ -0,0 +1,24 @@
+import { describe, it, expect } from "vitest";
+import { escapeSqlStringLiteral } from "../app/services/realtimeClient.server";
+
+describe("escapeSqlStringLiteral", () => {
+  it("leaves ordinary tag values unchanged", () => {
+    expect(escapeSqlStringLiteral("important")).toBe("important");
+    expect(escapeSqlStringLiteral("user_42")).toBe("user_42");
+    expect(escapeSqlStringLiteral("")).toBe("");
+  });
+
+  it("doubles a single quote", () => {
+    expect(escapeSqlStringLiteral("O'Brien")).toBe("O''Brien");
+  });
+
+  it("neutralizes the tags injection payload from #3739", () => {
+    const literal = `'${escapeSqlStringLiteral("test' OR '1'='1")}'`;
+    expect(literal).toBe("'test'' OR ''1''=''1'");
+    expect(literal.replace(/''/g, "")).toBe("'test OR 1=1'");
+  });
+
+  it("escapes every quote, not just the first", () => {
+    expect(escapeSqlStringLiteral("a'b'c'")).toBe("a''b''c''");
+  });
+});