I am currently having a lot of trouble setting up complex Firestore rules, but nothing worked so far and I would love if someone could help.
This is my root database structure:
groups
user_access
meetings
Where user_access has email address as key, and an object/list/value (more on that later) with the groupId he can access followed by the level of permission.
Every meeting has a groupId (where it belong).
So, I would like a rule to: check if the current groupId value from meetings is in the document at user_access with the current email address as key.
I thought about doing this rule (simplified below):
service cloud.firestore {
match /databases/{database}/documents {
match /meetings/{meetingId} {
function correctUser() {
return get(/databases/$(database)/documents/access/$(request.auth.token.email)).data.obj[get(/databases/$(database)/documents/meetings/$(meetingId)).data.groupId] == "leader"
}
allow read: if correctUser();
allow write: if correctUser();
}
}
But it doesn't work.. And I'm not sure why.
I tried making a list:
function correctUser() {
return get(/databases/$(database)/documents/meetings/$(meetingId)).data.groupId in get(/databases/$(database)/documents/access/$(request.auth.token.email)).data.list
}
But it also didn't work and I'm not sure why.
The best case scenario would be using a list of objects (a map), key(id),value(permission). Is that possible? Worst case scenario I can use a list for each different permission, or even put all the ids as value (I'll probably never reach the 20k fields limit).
So, I have two questions:
First, how can I make my rule(s) work?
Second, how do I call values from wildcards from inside fields? For example, on the example above with {meetingId}, how would I use this meetingId as a key? (...).data.meetingId? (...).data[$(meetingId)]? I found it very confusing and bad documented. What about on maps? Same thing?
Thanks!
It took me weeks to find out, but what I ultimately wanted and worked was:
function isLeader() {
return get(/databases/$(database)/documents/access/$(request.auth.token.email)).data[request.resource.data.groupId] == "leader"
|| get(/databases/$(database)/documents/access/$(request.auth.token.email)).data[resource.data.groupId] == "leader"
}
There is difference between request.resource.data.groupId and resource.data.groupId which I didn't know and was killing my requests, sometimes read, sometimes write. Glad it works now.
Related
I have studied the answer to this question (which has an extremely similar title): Per field rules in Firestore Security Rules. The solution in that case was to make a field unmodifiable, I do not think that is what I am after here.
I have a posts collection with a data structure as follows.
{
uid: string, // this is the original poster's UID
title: string,
content: string,
likesCount: number,
likerUIDs: string[]
}
I would like to restrict writes to the title and content fields to users with an auth token UID that matches the post's uid field. However, any authenticated user should be able to increment the likesCount and add their own UID to the likerUIDs field.
It seems like per-field security rules are not really supported. Is the solution here to maintain a separate collection with different rules but the same keys as the posts, for example post-likes, that contains the likesCount and likerUIDs fields? Or is there a firestore security rule trick to achieving this?
EDIT
Thanks to Doug and Frank's comments (extremely helpful video series by the way), I was able to come up with a solution to my initial question. As suggested in the accepted answer, I'm going to do this with a callable function, since it is perfect for this case. For those who stumble upon this question and want to accomplish something similar, I've pasted the rules I ended up with here. These rules accomplish exactly what is described in the question, but a callable function was definitely the way to go here.
function isOwnerCurrent() {
return request.auth.uid == resource.data.uid;
}
function isOwnerIncoming() {
return request.auth.uid == request.resource.data.uid;
}
function isUnmodified(key) {
return request.resource.data[key] == resource.data[key]
}
match /posts/{post} {
function validateNonOwnerPostUpdate() {
return isUnmodified('title') && isUnmodified('content') &&
isUnmodified('created') && isUnmodified('updated');
}
allow read: if true;
allow create: if isOwnerIncoming();
allow update: if (isOwnerCurrent() || validateNonOwnerPostUpdate()) && isUnmodified('uid');
allow delete: if isOwnerCurrent();
}
For updates, I am checking if the user is either the owner of the post, or only updating the so-called "public" fields of likesCount and likerUIDs, and for both they must not be modifying the owner UID of the post. Like mentioned in the accepted answer, this isn't great because anyone will be able to edit these fields and mess up the numbers.
I think it is better to use cloud function to solve this. you can use callable cloud function when that other users (not document owner) like that post. https://firebase.google.com/docs/functions/callable . because cloud function can bypass security rules
I think it is safer you do it through cloud function unless that likesCount is not that important. because if someone can hack your client app than they can modify your code. you will update the document like this
db.doc(`posts/${postID}`).update({
likesCount: admin.firestore.FieldValue.increment(1)
})
if they hack your app, then they can change the increment from 1 to 100 for example. yes you can do the same via security rules but you have to add additional check , and it will be complicated and error prone IMO.
I am struggling with an issue that is seemingly easy at first glance yet still does not work after trying dozens of different syntaxes. I've got a firebase database with a collection called users and every user has a subcollection 'posts'. What I want to achieve with implementing security rules is that one's posts can only be read by oneself if the account is private or by everyone if the account is public. Therefore, each user has got a boolean field isPublic. Sounds simple. This is my code:
match /users/{uid}{
function isPublic(){
return get(/databases/$(database)/documents/users/$(uid)).data.isPublic;
}
allow read, write: if request.auth.uid==uid
match /posts/{postid}{
allow read: if request.auth.uid==uid || isPublic();
}
The error is in line 3. If I hard code the uid (currently, I've got just 2 users) of user 2, who is public, and try to open his posts as user 1, it works fine. However, using the wildcard throws an exception every time.
return get(/databases/$(database)/documents/users/$(uid)).data.isPublic; //does not work
return get(/databases/$(database)/documents/users/uid).data.isPublic; //does not work
let userid = uid;
return get(/databases/$(database)/documents/users/$(userid)).data.isPublic; //does not work
let userid = string(uid);
return get(/databases/$(database)/documents/users/$(userid)).data.isPublic; //does not work
return get(/databases/$(database)/documents/users/ogfTdmsSG4dy2AHf8dp7LcPpd9B3).data.isPublic; //works
I would really appreciate I someone could tell me what the correct syntax is. Thank you very much in advance!
EDIT
The associated query that fails is:
_database.userCollection.document(idOfUser2).collection('posts').getDocuments();
It works fine when logged in as user 2 with security rules activated, and it works fine without security rules no matter of which user is making the request, but fails when user 1 is making the request with security rules activated.
Additionally, I should mention that if I use another function instead of get (for example, in line 5, like this:), it works fine as well.
allow read, write: if request.auth.uid==uid|| resource.data.isPublic
Thus, I came to the conclusion that the get command does not work. However, I need the get command as resource does not work in subcollections.
I'm trying to build a survey web app with firebase and have a certain user flow in my mind but I don't know if it can be done:
In this app you would signup/login and build your survey, which will be stored like this:
collection("creator").doc("creatorID").collection("surveyData").
After storing the data, you would get a link (e.g. webapp.com/forUser/secret/surveyName) you then can share with your friends. This link opens the same web app (from another entry point) but with anonymous authentication, hydrating and displaying only the content of this one survey from this one user.
There are two main problems here:
Pointing the user's web app to the right data via the link and only being able to access this one survey.
Writing the user answers in the creator's files
For 1) Can I pass a secret via the link (could I use the creatorID for this or is this not safe/secure?), which points the user to this one survey data (without granting any other access)? If so, how to do this without hard coding the secret into the authentication rules?
For 2) I could use a two-step process:
The user answers the survey questions and the results are stored in something like:
collection("user").doc("secret").collection("surveyData").
When the creator opens the app later on (or done via cloud functions), the app fetches all the answers from the shared secret doc. Can this be done in one step?
I hope this makes sense somehow. Maybe my ideas are way too complicated and there is an easy way to do this or are there some best practices in this regard?
Thanks for your help!
A while ago I built a hashing package into Firebase Rules. It might be possible to use that?
Example rules:
rules_version="2"
function hashUserCreds(auth) {
let combinationOfCreds = string(auth.uid) /* + string(auth.other.stuff) */;
// hashing.sha256 will work on strings as well, but it's more readable to
// make this explicit.
return hashing.sha256(combinationOfCreds.toUtf8()).toBase64();
}
service cloud.firestore {
match /databases/{database}/documents {
match /{ownerHash}/{surveyId} {
function isOwner() {
return hashUserCreds(request.auth) == ownerHash;
}
allow read;
allow write: if isOwner();
match /{responseId} {
function isResponder() {
return hashUserCreds(request.auth) == responseId;
}
allow update: if isResponder();
allow read, create: if isOwner();
}
}
}
}
If you want open-responses then you change the final two permissions, but it sounds like you want the survey creator to choose who can respond which I've tried to express there.
Using hashes instead of names will provide better anonymity, obscure PII, and force the restriction that a user can only edit their data.
It's a simple and common use case of security rule, but cannot make it work.
I have a document orgs/fooOrg on my Firestore(not RTDB), and it contains an object
{
"members": {
"fooUser": true
}
}
and the rule applied is
service cloud.firestore {
match /databases/{database}/documents {
match /orgs/{orgId} {
allow read: if "fooUser" in resource.data.members;
}
}
}
I expect all the document in orgs collection should be able to be read; however, the server says Error: Missing or insufficient permissions as a result of running
firebase.firestore().doc('orgs/fooOrg').get()
on a browser (using v4.5.0 and v4.5.1). Even
allow read: if resource.data.members["fooUser"] == true;
fails, too. What went wrong?
In my understanding, this should work according to this document
https://firebase.google.com/docs/firestore/security/secure-data#evaluating_documents_currently_in_the_database
I believe that it was working like a week ago. All the sudden, my working code started to generate the error, so I wrote this MCVE and tested on several different projects.
In addition, I found similar issues below, but a bit different from them, so not sure if it's the same reason (a bug on Firestore)
Firestore security rules based on map values
(My case, even getting a simple document fails)
Firestore read rules with self condition
(This case uses a value of a map. My case, a key is used)
Now seems that the issue is solved without changing code. No announcement, but seems that something is fixed by Firestore side.
I want to store if a user is permitted to read a document in the document itself, based on the user's email address. Multiple users should have access to the same document.
According to the documentation Firestore does not allow querying array members. That'S why I'm storing the users email addresses in a String-Bool Map with the email address as a key.
For the following example I'm not using emails as map keys, because it already doesn't work with basic strings.
The database structure looks like that:
lists
list_1
id: String
name: String
owner: E-Mail
type: String
shared:
test: true
All security rules are listed here:
service cloud.firestore {
match /databases/{database}/documents {
match /lists/{listId=**} {
allow read: if resource.data.shared.test == true
}
}
}
Edit: It also doesn't work if I use match /lists/{listId} instead of match /lists/{listId=**}
How I understand it, this security rules should allow reading access to everyone if the value in the map shared[test] is true.
For completness sake: This is the query I'm using (Kotlin on Android):
collection.whereEqualTo("shared.test", true).get()
.addOnCompleteListener(activity, { task ->
if (task.isSuccessful) {
Log.i("FIRESTORE", "Query was successful")
} else {
Log.e("FIRESTORE", "Failed to query existing from Firestore. Error ${task.exception}")
}
})
I'm guessing that I cannot access map values from the security rules. So what would be an alternative solution to my problem?
In the Firestore rules reference it's written that maps can be accessed like that resource.data.property == 'property' so, what am I doing wrong?
Edit: This issue should be fixed now. If you're still seeing it (and are sure it's a bug with the rules evaluator), let me know in the comments.
I've chatted with some folks here about the problem you're encountering, and it appears to be an issue with the security rules itself. Essentially, the problem seems to be specific to evaluating nested fields in queries, like what you're doing.
So, basically, what you're doing should work fine, and you'll need to wait for an update from the Firestore team to make this query work. I'll try to remember to update this answer when that happens. Sorry 'bout that!
Whenever you have (optional) nested properties you should make sure the property exists before continuing to check its' value eg.
allow read: if role in request.auth.token && request.auth.token[role] == true
in your case:
allow read: if test in resource.data.shared && resource.data.shared.test == true
, I was struggling a long time with roles until I realized that on non-admin users the admin field is undefined and firestore rules just crashes and doesn't continue checking other possible matches.
For a user without token.admin, this will always crash no matter if you have other matches that are true eg:
function userHasRole(role) {
return isSignedIn() && request.auth.token[role] == true
}