Create group access to firebase storage without using custom authorization - firebase

Is there a way to control uploads to a path in Firebase Storage by group?
For instance have an admin group that can upload anywhere or a team that can only upload to a certain path.

After searching around a bit, I didn't find a ready answer, so I'll post what I have so far. It would be nice to know if there are other (better) ways of doing this.
Since I'm trying NOT to use another server, custom authentication tokens are out. However, the request.auth.uid is available to the storage rules. The uid property matches one of the users defined in the Auth area. You'll need to create a function in the storage rules that checks if request.auth.uid is in a group you define.
Firebase storage rules have a unique syntax. It sorta looks like javascript, but it's not. You can define functions, but you can't declare a var within them. Furthermore there is a subset of javascript-like methods available.
For instance, I first unsuccessfully tried the following:
function isAdmin() {
return ["value","list"].indexOf(request.auth.uid) > -1;
}
service firebase.storage {...}
Either the rules editor threw errors when I tried to define a var OR it always returned "unauthorized" when I used .indexOf.
The following ended up working for me.
function isAdmin() {
return request.auth.uid in {
"yaddayadddayaddUserIDKey":"User Name1"
};
}
function isSomeOtherGroup() {
return request.auth.uid in {
"yaddayaddaSomeOtherUID":"User Name2",
"YaddBlahBlahUID":"User Name3"
};
}
service firebase.storage {
match /b/<your bucket here>/o {
match /{allPaths=**} {
allow read, write: if isAdmin();
}
match /path/{allPaths=**} {
allow read, write: if isSomeOtherGroup() || isAdmin();
}
}
}

I don't have enough reputation to comment on #ecalvo's answer. So I am adding an answer. The function isAdmin() can be provided a list as following:
function isAdmin() {
return request.auth !=null && request.auth.uid in [
"uidAdmin1",
"uidAdmin2",
"uidOfOtherAdminsAsCommaSeparatedStrings"
];
}
Rest of the implementation can be borrowed from the answer of #ecalvo. I feel now it is more clear. In the answer of #ecalvo, I was confused why should I give username when I have to compare only uid.

Related

Firebase query, rule for collectiongroup query getting in the way

Just when I thought I had the hang of it, the query rules throws me a curve ball :(
I have this query rule:
// Needed for collection group (Member) query
// https://firebase.googleblog.com/2019/06/understanding-collection-group-queries.html
match /{rootPath=**}/Members/{member} {
allow read: if request.auth != null;
}
It's pretty basic, only needs an authorized user. collectiongroup query works perfectly as expected.
Now, I want to have another query just to get member documents:
Firebase.firestore.collection("Companies\\$companyID\\Members").get().await()
The query returns an error (PERMISSION_DENIED).
I also tried adding a rule just for members like this:
match /Companies/{companyID} {
allow read: if request.auth != null &&
isMember(database, companyID, request.auth.uid)
match /Members/{member} {
allow read: if request.auth != null
}
}
Still, the same error.
This is the document path:
I looked at a few resources, but I didn't see anything to suggest a solution:
Understanding Collection Group Queries in Cloud Firestore
Recursive wildcards
I am posting this as an answer, as it is too long for comment.
Have you tried the following example rule:
service cloud.firestore {
match /databases/{database}/documents {
match /Companies/{companyID}/Members/{member} {
allow read, write: if <condition>;
}
}
}
as mentioned earlier in the documentation you shared based on structuring rules with hierarchical data?
I would recommend that you have a look at the following documentation where you can find some examples:
service cloud.firestore {
match /databases/{database}/documents {
match /Companies/{companyID}/Members/{memberID} {
// Only authenticated users can read
allow read: if request.auth != null;
}
}
}
Using the above security rules, any authenticated user can retrieve the members of any single company:
db.collection("Companies/{companyID}/Members").get()
Now , if you would like to have the same security rules applied to collection group queries, you must use version 2:
rules_version = '2';
service cloud.firestore {
match /databases/{database}/documents {
// Authenticated users can query the posts collection group
// Applies to collection queries, collection group queries, and
// single document retrievals
match /{path=**}/Members/{memberID} {
allow read: if request.auth != null;
}
}
}
Any authenticated user can retrieve the members of any single company:
But what if you want to show a certain user their members across all companies? You can use a collection group query to retrieve results from all members collections:
var user = firebase.auth().currentUser;
db.collectionGroup("members").where("author", "==", user.uid).get()
Note: This query requires will require a composite index for the members collection. If you haven't enabled this index, the query will return an error link you can follow to create the required index.
You can try using "match /{path=**}/Members/{member}" instead of rootPath. I have not used the latter but the former worked for me in other projects.

Firestore security rules get field/id of reference

I have two collections - tenancies and users.
A tenancy doc has a field called "landlordID" and is of type REFERENCE (not String).
Now in my Firestore Security Rules I want to allow a tenancy to be updated ONLY IF the landlordID field of that tenancy matches with the uid of the user making the request, namely request.auth.uid.
Read it as " allow a tenancy document to be updated if the user making the user is authenticated, hence request.auth.uid != null, and the landlordID field's ID should be equal to that of the request.auth.uid.
Hence the code should me something like this:
service cloud.firestore {
match /databases/{database}/documents {
match /tenancies/{tenancyID}{
allow update: if request.auth.uid != null &&
request.auth.uid == get(resource.data.landlordID).id
}
}
I have also tried get(/databases/$(database)/documents/users/$(resource.data.landlordID)).data.id
Supporting screenshot of my database
This should be very simple but get() simply does not work. Firebase Docs, scroll to "Access other documents" was not helpful at all for my situation and I am not sure how to get it working.
It would be a shame if references can't be used like this as they are just like any other field of a document.
Here is a function I made that works for me. I guess you have a user collection with users having the same id as their auth.uid
function isUserRef(field) {
return field in resource.data
&& resource.data[field] == /databases/$(database)/documents/users/$(request.auth.uid)
}
Adjusting to your use case you'd call the function so: isUserRef('landlordID') although the ID at the end of it is a bit misleading as this field is in fact a reference.
I see a couple of issues here. A first problem is that the get() function expects a fully specified ducument path, something like:
get(/databases/$(database)/documents/users/$(resource.data.landlordID)).data.id
A second problem is that you are trying to use the reference type in your rules, I do not think that is possible unfortunately.
The reference type in Firestore is not very helpfull (yet), I think you should store the landlordID as a string, then you can simply do something like:
service cloud.firestore {
match /databases/{database}/documents {
match /tenancies/{tenancyID}{
allow update: if request.auth.uid != resource.data.landlordID;
}
}
I had the same issue I needed an answer for. See this Google-thread with the answer from someone from google. To quote it:
You can get an id out of a path using the "index" operator:
some_document_ref should look like /databases/(default)/documents/foo/bar
which has 5 segments: ["databases", "(default)", ...]
some_document_ref[4] should be "bar"
allow create: if request.resource.data.some_document_ref[4] == "bar";
You can also use the normal get and exists functions on them.
A few difficult aspects of this that you may run into:
There's no way to retrieve the number of segments in a path at the moment (we're adding this soon), so you'll need to know some information about the reference ahead of time
There's not great support for writing references using the simulator in the Firebase Console. I used the Firestore emulator to test out this behavior (gist1, gist2)
might be too late, but I was able to piece together (despite a lack of docs) that a document reference is just a path, and complete path can be created with
/databases/$(database)/documents/users/$(request.auth.uid)
Then I have an array/list in firestore of references, called reads that I can grab with:
get(/databases/$(database)/documents/users/$(userId)/userinfo/granted_users).data.reads
Leaving me able to create a bool, and a rule with:
/databases/$(database)/documents/users/$(request.auth.uid) in get(/databases/$(database)/documents/users/$(userId)/userinfo/granted_users).data.reads
obviously your data structure will vary, but knowing the ref is a path is the important part here.
I had to experiment a little to get this working. Here the function that worked for me
function isUserRef(database, userId) {
return 'user' in resource.data
&& resource.data.user == /databases/$(database)/documents/users/$(userId);
}
And I call it like:
match /answers/{answer} {
allow read:
if isUserRef(database, request.auth.uid);
}
As mentioned by some other answers, a reference has a path property that is just a string that will look something like users/randomuserid123. You can split that into an array and match it against the user making the update request.
...
match /tenancies/{tenancyID}{
allow update: if request.auth.uid != null &&
resource.data.landlordID.path.split('/') == ['users', request.auth.uid]
}
...
Also had a trouble handling this problem, but in my case I needed to allow the user to add a message into a chat only if they're the owner of that chat room. There are 2 "tables" - chats and chat_messages, and chat_messages relate to a specific chat through chatId field. chats objects have ownerId field.
The rule I've used goes like this:
// Allow adding messages into a chat if the user is an owner of the chat room
match /chat_messages/{itemId} {
function isOwner() {
return get(/databases/$(database)/documents/chats/$(request.resource.data.chatId)).data.ownerId == request.auth.uid;
}
allow read: if true;
allow create: if isOwner();
}

Firestore security rules for specific document

I am trying to apply the following situation :
all authenticated users have read and write access to the database except for admin document.
Admin document is accessible only for him for read and write.
My rules:
service cloud.firestore {
match /databases/{database}/documents {
//Functions
function isAuthenticated(){
return request.auth != null;
}
function isAdministrator(){
return request.auth != null && request.auth.token.name == resource.data.oid;
}
//Administrator Identity Check Point
match /admin/identity {
allow read, write: if isAdministrator();
}
//Allow Reads and Writes for All Authenticated Users
match /{document=**}{
allow read, write: if isAuthenticated();
}
}//databases/{database}/documents
}//cloud.firestore
Is there any way i can achieve this, actually when testing these rules, the tests succeed because only isAuthenticated() is being called because of the tag /{document=**}. I also tried /{document!=/admin/identity} but it does not work.
How can I write a security rule that follow this model ?
Maybe on your default user rule you could check if the collection isn't admin, something like this:
//Allow Reads and Writes for All Authenticated Users
match /{collection}/{document=**}{
allow read, write: if (isAuthenticated() && collection != "admin") || isAdministrator();
}
Since June 17, Firebase has provided new improvements to Firestore Security Rules.
Firebase blog - 2020/06 - New Firestore Security Rules features
New Map methods
We'll use Map.get() to get the "roleToEdit" field. If the document doesn't have the field, it will default to the "admin" role. Then we'll compare that to the role that's on the user's custom claims:
allow update, delete: if resource.data.get("roleToEdit", "admin") == request.auth.token.role;
Local variables
Say you're commonly checking that a user meets the same three conditions before granting access: that they're an owner of the product or an admin user.
rules_version = '2';
service cloud.firestore {
match /databases/{database}/documents {
function privilegedAccess(uid, product) {
let adminDatabasePath = /databases/$(database)/documents/admins/$(uid);
let userDatabasePath = /databases/$(database)/documents/users/$(uid);
let ownerDatabasePath = /databases/$(database)/documents/$(product)/owner/$(uid);
let isOwnerOrAdmin = exists(adminDatabasePath) || exists(ownerDatabasePath);
let meetsChallenge = get(userDatabasePath).data.get("passChallenge", false) == true;
let meetsKarmaThreshold = get(userDatabasePath).get("karma", 1) > 5;
return isOwnerOrAdmin && meetsChallenge && meetsKarmaThreshold;
}
match /products/{product} {
allow read: if true;
allow write: if privilegedAccess();
}
match /categories/{category} {
allow read: if true;
allow write: if privilegedAccess();
}
match /brands/{brand} {
allow read, write: if privilegedAccess();
}
}
}
The same conditions grant access to write to documents in the three different collections.
Ternary operator
This is the first time we've introduced an if/else control flow, and we hope it will make rules smoother and more powerful.
Here's an example of using a ternary operator to specify complex conditions for a write.
A user can update a document in two cases: first, if they're an admin user, they need to either set the field overrideReason or approvedBy. Second, if they're not an admin user, then the update must include all the required fields:
allow update: if isAdminUser(request.auth.uid) ?
request.resource.data.keys().toSet().hasAny(["overrideReason", "approvedBy"]) :
request.resource.data.keys().toSet().hasAll(["all", "the", "required", "fields"])
It was possible to express this before the ternary, but this is a much more concise expression. ;)

Firebase Firestore: custom admin access

In Firebase Firestore, I'm trying to allow only (custom-assigned) admins to write/update/delete resources, and for that I've got these security rules:
service cloud.firestore {
match /databases/{database}/documents {
match /resources {
allow read;
allow write, update, delete: if get(/users/$(request.auth.uid).isAdmin);
}
match /resources/{resource} {
allow read;
allow write, update, delete: if get(/users/$(request.auth.uid).isAdmin);
}
}
}
I'm signing in with the user that is marked as an admin in the users collection:
NfwIQAjfNdS85yDvd5yPVDyMTUj2 is the UID gotten from the Authentication pane:
However, for some reason (UPDATE: reasons identified; see answer), I'm getting PERMISSION_DENIED errors when writing to the resources collection after being absolutely sure I'm signed in with the admin user.
Perhaps it is possible to view request logs from Firestore? Then I could have a look at what request.auth.uid looks like to match it up with my collections and rules.
While writing my question, I made it work! I made two mistakes, both of which could have been avoided if I read the docs properly.
Firstly, all calls to the service-defined function get needs to prefix the path with /databases/$(database)/documents/. So that this rule:
allow write: if get(/users/$(request.auth.uid)).isAdmin;
becomes this:
allow write: if get(/databases/$(database)/documents/users/$(request.auth.uid)).isAdmin;
It's long, I know, but that's how it is. I'm not sure why Firestore isn't able to do that by itself, though, seeing as that same path prefix will stay the same across all calls to get, but perhaps this is for some future feature that isn't ready yet, like cross-database querying or something.
Second, the get function will return a resource, which in turn you'll need to call .data on to get the actual data that it contains. Thus, instead of doing this:
get(/path/to/user/).isAdmin
you'll need to do this:
get(/path/to/user/).data.isAdmin
Now I just wish I was able to extract that logic into a user-defined function:
function isAdmin() {
return get(/databases/$(database)/documents/users/$(request.auth.uid)).data.isAdmin;
}
But doing so results in a PERMISSION_DENIED again, and without knowing what's actually going on in the function, I'm not sure if I'll spend more time trying to figure this out now.
UPDATE: #Hareesh pointed out that functions must be defined within the scope of a matcher, so it's possible to put the function in the default top-level matcher like this:
service cloud.firestore {
match /databases/{database}/documents {
function isAdmin() {
return get(/databases/$(database)/documents/users/$(request.auth.uid)).data.isAdmin == true;
}
// ...
}
}
Some points i noticed
match /resources is pointing to a collection, that rules has no effect on its documents. here i am quoting from the doc
Rules for collections don't apply to documents within that collection. It's unusual (and probably an error) to have a security rule that is written at the collection level instead of the document level.
so you don't have to write rules for collections
Then in the rules allow write, update, delete: you can say either allow write: or specifically allow create, update, delete: any of the three options or combine them.
try this
service cloud.firestore {
match /databases/{database}/documents {
match /resources/{resource} {
function isAdmin() {
return get(/databases/$(database)/documents/users/$(request.auth.uid)).isAdmin ||
get(/databases/$(database)/documents/users/$(request.auth.uid)).data.isAdmin;
}
allow read;
allow create, update, delete: if isAdmin();
}
}
}

Recursive wildcards in Firestore security rules not working as expected

I have a data structure like this (Collections and Documents rather than JSON of course but you get the idea):
{
users: {
user1:{
name: Alice,
groups: {
groupA:{subbed:true},
groupB:{subbed:true}
}
},
user2:{
name: Bob,
groups: {
groupC:{subbed:true},
groupD:{subbed:true}
}
}
}
}
Basically this is registered users IDs and the group IDs that each user is subscribed to. I wanted to write a security rule allowing access to a users profile and sub-collections only if they are the current auth user and, based on my reading of the docs, I thought that a wildcard would achieve this...
match /users/{user=**}{
allow read,write: if user == request.auth.uid;
}
With this in place I can read the user document fine but I get a permissions error when I try and read the groups sub-collection. I can only make it work by matching the sub-collection explicitly...
match /appUsers/{user}{
allow read,write: if user == request.auth.uid;
match /groups/{group}{
allow read,write: if user == request.auth.uid;
}
}
...so my question is, what is the difference between the two examples and what am I misunderstanding about the recursive wildcards? I thought that the {user=**} part of the first example should grant access to the user document and all its sub-collections, sub-sub-collections etc etc ad infinitum (for the authorised user) and should remove the need to write rules specifically for data stored lower down as I have had to do in the second example.
I've only been messing around with Firestore for a short time so this could be a real dumb question :)
Thanks all
The firebase docs are a bit confusing when it comes to using the recursive while card. What I found in testing was that I needed to set two rules to give a user permission to write to the users document and all sub collections (and their sub documents) which is the most logical setup for managing user data.
You must set two rules.
Give user permission to the /users/{userId} document
Give user permission to all sub collections and their sub documents that begin at the /users/{userId} path.
service cloud.firestore {
match /databases/{database}/documents {
match /users/{userId} {
allow read, write: if request.auth.uid == userId;
}
match /users/{userId}/{document=**} {
allow read, write: if request.auth.uid == userId;
}
}
}
Rules
Sorry about including the images. I couldn't get SO to format them correctly.
I think the problem is that, while you are indeed using the subcollections wildcard =**, you are then allowing permissions only if user == request.auth.uid, so this is what happens (pseudocode):
(when accessing users/aHt3vGtyggD5fgGHJ)
user = 'aHt3vGtyggD5fgGHJ'
user == request.auth.uid? Yes
allow access
(when accessing users/aHt3vGtyggD5fgGHJ/groups/h1s5GDS53)
user = 'aHt3vGtyggD5fgGHJ/groups/h1s5GDS53'
user == request.auth.uid? No
deny access
You have two options: either you do as you've done and explicitly match the subcollection, or use this:
function checkAuthorization(usr) {
return usr.split('/')[0] == request.auth.uid;
}
match /users/{user=**}{
allow read,write: if checkAuthorization(user);
}
(the function must be inside your match /databases/{database}/documents, like your rule)
Let me know if this works :)
Security rules now has version 2.
match/cities/{city}/{document=**} matches documents in any
subcollections as well as documents in the cities collection.
You must opt-in to version 2 by adding rules_version = '2'; at the top
of your security rules.
Recursive wildcards (version 2).
This is what works for me:
rules_version = '2';
service cloud.firestore {
match /databases/{database}/documents {
// Matches any document in the cities collection as well as any document
// in a subcollection.
match /cities/{city}/{document=**} {
allow read, write: if <condition>;
}
}
}

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