Ensure sensitive details are never logged via CallStack

src/models/callStack.js

@@ -20,23 +20,64 @@ module.exports = class CallStack {
 
   // Attempts to remove any sensitive data that may be found within
   sanitize(content) {
-    if (typeof content !== "object") {
-      return content;
-    }
 
+    const badKeys = [
+      "token",
+      "password",
+      "pass",
+      "auth",
+      "secret",
+      "passphrase",
+      "card"
+    ];
+    const githubTokenReg = /(?:gho_|ghp_|github_pat_|ghu_|ghs_|ghr_)/;
+    const hideString = "*****";
     let outContent = {};
+    let type = typeof content;
 
-    for (const key in content) {
-      switch (key) {
-        case "token":
-          outContent[key] = "*****";
-          break;
-        default:
-          outContent[key] = content[key];
-          break;
+    // Since JavaScript `typeof` will assign an array as "object" as well as null
+    // we will extend this typeof check to add those as different types, to ease
+    // the complexity of the below switch statement
+    if (type === "object") {
+      if (Array.isArray(content)) {
+        type = "array";
+      } else if (content === null) {
+        type = "null";
       }
     }
 
+    switch(type) {
+      case "object":
+        for (const key in content) {
+          // Match different possible keys that represent sensitive data
+          if (badKeys.includes(key)) {
+            outContent[key] = hideString;
+          } else {
+            outContent[key] = this.sanitize(content[key]);
+          }
+        }
+        break;
+      case "string":
+        // Match different strings of sensitive data
+
+        // https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/about-authentication-to-github#githubs-token-formats
+        if (githubTokenReg.test(content)) {
+          outContent = hideString;
+        } else { // More strings to test can be added here
+          // String seems safe
+          outContent = content;
+        }
+        break;
+      case "array":
+        outContent = [];
+        for (let i = 0; i < content.length; i++) {
+          outContent.push(this.sanitize(content[i]));
+        }
+        break;
+      default:
+        outContent = content;
+    }
+
     return outContent;
   }
 };

tests/unit/models/callStack.test.js

@@ -0,0 +1,82 @@
+const callStack = require("../../../src/models/callStack.js");
+const hideValue = "*****";
+
+describe("Sanitizes content as expected", () => {
+  test("Leaves safe data unmodified", () => {
+    const cs = new callStack();
+
+    const before = {
+      value: "Safe data"
+    };
+
+    const after = cs.sanitize(before);
+
+    expect(after).toEqual(before);
+  });
+
+  test("Removes value of a key starting with 'token'", () => {
+    const cs = new callStack();
+
+    const before = {
+      token: "super_secret"
+    };
+
+    const after = cs.sanitize(before);
+
+    expect(after).toEqual({ token: hideValue });
+  });
+
+  test("Removes value of an unsafe string", () => {
+    const cs = new callStack();
+
+    const before = "gho_value";
+
+    const after = cs.sanitize(before);
+
+    expect(after).toEqual(hideValue);
+  });
+
+  test("Removes deeply nested unsafe string", () => {
+    const cs = new callStack();
+
+    const before = { value: { value: { value: { value: "github_pat_value" }}}};
+
+    const after = cs.sanitize(before);
+
+    expect(after).toEqual({ value: { value: { value: { value: hideValue }}}});
+  });
+
+  test("Removes unsafe value from array", () => {
+    const cs = new callStack();
+
+    const before = [{}, {}, { token: "super_secret" }];
+    const after = cs.sanitize(before);
+
+    expect(after).toEqual([{}, {}, { token: hideValue }]);
+  });
+
+  test("Doesn't break on 'null'", () => {
+    const cs = new callStack();
+
+    const before = null;
+    const after = cs.sanitize(before);
+
+    expect(after).toEqual(null);
+  });
+
+  test("Removes all known github token formats", () => {
+    const cs = new callStack();
+
+    const before = [
+      { v1: "ghp_personal_access_token_classic" },
+      { v2: "github_pat_fine_grained_personal_access_token" },
+      { v3: "gho_oauth_access_token" },
+      { v4: "ghu_user_access_token_for_github_app" },
+      { v5: "ghs_installation_access_token" },
+      { v6: "ghr_refresh_token_for_github_app" }
+    ];
+    const after = cs.sanitize(before);
+
+    expect(after).toEqual([{v1: hideValue}, {v2: hideValue}, {v3: hideValue}, {v4: hideValue}, {v5: hideValue}, {v6: hideValue}]);
+  });
+});