Over a million developers have joined DZone.

Grant Right to Use $Eval on MongoDB 3.2

DZone's Guide to

Grant Right to Use $Eval on MongoDB 3.2

How do you enable a user to execute the $eval command in MongoDB? You might not think this is an issue, but you might also be surprised. Read on to find out more.

· Database Zone ·
Free Resource

Running out of memory? Learn how Redis Enterprise enables large dataset analysis with the highest throughput and lowest latency while reducing costs over 75%! 

One of the side effects of enabling authorization on MongoDB is that, even if you create a user with “root” right, this account is not able to execute the $eval command. The symptom is, when you try to execute $eval you get this error:

mongodb Command '$eval' failed: not authorized on jarvis-framework-saga-test to execute command

This happens because $eval is somewhat deprecated, and it should not be used. Since it is a dangerous command, a user should have access to all action on all resources, and you need to create a role that has anyAction on anyResource.

If you really need to use $eval, you should create a role. Just connect to the admin database and create a new role with the command.

role: "executeEval", 
privileges: [ { 
resource: { anyResource: true }, 
actions: [ "anyAction" ] } ], 
roles: []
 } ) 

Now that you have this new role, just add it to all the users that need to use $eval. As an example, if you have a single admin user in the admin database, just run this against the admin DB.

db.grantRolesToUser("admin", [ { role: "executeFunctions", db: "admin" } ])

And now, the admin user can execute $eval against all databases.

Running out of memory? Never run out of memory with Redis Enterprise databaseStart your free trial today.

mongodb ,database ,authorization ,users ,permissions

Published at DZone with permission of

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}