EvaluationException when using crosss-service security rule with Emulator

[johnnyoshika]

[REQUIRED] Environment info

firebase-tools: 11.16.1

Platform: Windows

[REQUIRED] Test case

Use cross-service security rule (i.e. firestore.get()) in storage.rules:

rules_version = '2';
service firebase.storage {
  match /b/{bucket}/o {
    match /courses/{courseId}/files/{fileName} {
      allow get: if firestore.get(/databases/(default)/documents/courses/$(courseId)).data.users[request.auth.uid].exists;
    }
  }
}

Add the following document to Emulator's Firestore at courses/course1:

{
  users: {
    user1: { exists: true }
  }
}

[REQUIRED] Steps to reproduce

Download file from storage using the JavaScript client SDK:

    const storage = getStorage();
    const fileRef = ref(storage, 'courses/4VnY71FQeT6XDAGNDjSSX/files/foo.txt');
    const url = await getDownloadURL(fileRef);
    const response = await fetch(url);

[REQUIRED] Expected behavior

Based on this announcement: https://firebase.blog/posts/2022/09/announcing-cross-service-security-rules, I expected cross-service security rules to be supported automatically for firebase-tools@11.10.0 and above.

[REQUIRED] Actual behavior

firestore.get() inside the storage rules results in this exception, so the security rule never allows the request:

  com.google.firebase.rules.runtime.common.EvaluationException: Error: C:\Users\...\storage.rules line [5], column [31]. Service call error. Function: [firestore.get], Argument: [path_value {
  segments {
    simple: "databases"
  }
  segments {
    simple: "(default)"
  }
  segments {
    simple: "documents"
  }
  segments {
    simple: "courses"
  }
  segments {
    simple: "4VnY71FQeT6XDAGNDjSSX"
  }
}
].

[sam-gc]

I'm unable to reproduce this issue. Using your rules and version 11.16.1, everything works as expected on my end. Just to double check, you're also using the Firebase Auth emulator as well right?

[johnnyoshika]

@sam-gc I'll try to reproduce it in a fresh environment. I'll share the repo if I can.

[johnnyoshika]

Just to double check, you're also using the Firebase Auth emulator as well right?

@sam-gc Yes

[onra2]

I got the same problem.

having a create if: isManagerInRoles(idVenue)
and 2 functions as:

function getEmailFromUserRequest(){
  return firestore.get(/databases/(default)/documents/users/$(request.auth.uid)).data.email;
}

function isManagerInRoles(venueId){
  return firestore.get(/databases/(default)/documents/roles/$(getEmailFromUserRequest())).data.venues[venueId] == 0;
}

When debugging it finds the email of my user. When hardcoding the email, it works too, but the function call fails.

[johnnyoshika]

@sam-gc I created a fresh new firebase local dev environment using the emulator and I wasn't able to repro this issue. Everything worked as expected. Now I have the fun task of figuring out why it works in the isolated environment but not in my other project.

Do you know what can cause this exception? com.google.firebase.rules.runtime.common.EvaluationException? Any hint may lead me in the right direction.

[johnnyoshika]

@onra2 are you also getting this exception?

com.google.firebase.rules.runtime.common.EvaluationException

[onra2]

yes i get the exact same error as you

[onra2]

if i may add my steps to reproduce:

have a collection "roles"
in that collection add a document with id = "test@gmail.com"
in that document add a field "venues" (type map) and inside that map an entry: 123456: 0

have a collection "users"
when logging in, i create a document for the user, (id of document is the uid of the user)
that user has a field "email" equal to his email.

basically i want to check if a user has the "0" role from the venue he is in to upload an image.

in my view i have:

async uploadImage(image: string, path: string){
    const storageRef = ref(this.storage, path);
    uploadString(storageRef, image, 'data_url');
  }

await this.uploadImage(this.imageURLData, "123456/venue_cover.png");

in the rules i have:

match /{idVenue}/{imgName}{
    allow read: if true;
    allow create: if isManagerInRoles(idVenue) && imgName == "venue_cover.png";
  }

  function getEmailFromUserRequest(){
    return firestore.get(/databases/(default)/documents/users/$(request.auth.uid)).data.email;
  }

  function isManagerInRoles(venueId){
    return firestore.get(/databases/(default)/documents/roles/$(getEmailFromUserRequest())).data.venues[venueId] == 0;
  }

when debugging, getEmailFromUserRequest() gets the correct email from my user.
And isManagerInRoles gets the correct value if the email is hardcoded in the rule. But combining both functions like shown above doesn't work and raises an com.google.firebase.rules.runtime.common.EvaluationException exception.

I hope this helps.

[kalenmike]

I am getting the same error anytime I call firestore.get, the column error is on get:

firestore.get(/databases/(default)/documents/users/GkbacaBOL8eKrcLGXxgRjEiJOYpk);

com.google.firebase.rules.runtime.common.EvaluationException: Error: /home/ace/Projects/a/websites/b/c/storage.rules line [10], column [27]. Service call error. Function: [firestore.get], Argument: [path_value {
  segments {
    simple: "databases"
  }
  segments {
    simple: "(default)"
  }
  segments {
    simple: "documents"
  }
  segments {
    simple: "users"
  }
  segments {
    simple: "GkbacaBOL8eKrcLGXxgRjEiJOYpk"
  }
}
]

I am using firebase-tools 11.17.0 and using the emulators. Active emulators are Authentication, Functions, Firestore, Database, Hosting, Storage.

[johnnyoshika]

I was able to reproduce the bug. The exception occurs if the Firestore document contains a field with a value of null. If there are no fields with a value of null, everything works as expected.

@sam-gc I created this repo for you to reproduce: https://github.com/examind-ai/firebase-tools-cross-service-rules

Follow the instructions in README and you'll experience the EvaluationException. It's due to having this deletedAt: null value in the Firestore document: https://github.com/examind-ai/firebase-tools-cross-service-rules/blob/2af68b07df15b796d78174314f813d4102e75420/hosting/src/App.tsx#L28

Remove that one line of code and run the application again and the exception will not occur.

Here's a video demo using the sample repository linked above:

Media1.mp4

Don't ask me how long it took me to figure this out 😖