Permissions

zoom_0.mp4

Background

Iroha Special Instructions and Iroha Queries processing requires a permissions based security model.

Whitepaper and Iroha v1 documentation were researched. The proposal is to use already existing Iroha Special Instructions + Assets mechanisms for Permissions implementation. 

Problem

The White Paper requires protection of data from unauthorized read and write access.

Iroha 1 documentation gives a Permission's definition:

A named rule that gives the privilege to perform a command. Permission cannot be granted to an account directly, instead, account has roles, which are collections of permissions. Although, there is an exception, see Grantable Permission.

and Grant-able Permission:

Only grantable permission is given to an account directly. An account that holds grantable permission is allowed to perform some particular action on behalf of another account. For example, if account a@domain1 gives the account b@domain2 a permission that it can transfer assets — then b@domain2 can transfer assets of a@domain1 to anyone.

As you can see permissions were a first-level entities in Iroha 1 while they can be easily implemented by Iroha Special Instructions + Assets.

Solution

Permissions can be implemented as Iroha 2 Module and stored as assets under account that "owns" them. Then all out-of-the-box Iroha Special Instructions and Iroha Queries will trigger execution of permission check.

Permission check is an execution of `FindAssetsByAccountIdAndAssetDefinitionId` Iroha Query result and check that set of assets is not empty (containing permission needed).

Additionally to solving the problem it brings interesting advantages:

• we do not need to worry about Genesis Block and Network Setup problems (manual initial state configuration vs disabled state during genesis block commit) - we can place permissions module related entities (domains, asset definitions, triggers) commit after basic entities (root account, etc.) commit
• usage of Iroha Queries as a declarative API gives an ability for performance improvements (caches, batch executions, etc.)
• Iroha modules and users can "deploy" own permissions and checks without a need to compile them or to restart Iroha Peers
• private blockchains that do not need permissions module can remove it from the Genesis Block
  • `+` growth in performance
  • `-` additional client-side security checks needed

Decisions

• Store permissions as Iroha Assets
• Check permissions by Iroha Triggers
• Place initial configuration inside additional Permissions Iroha Module and apply it from the Genesis Block

Alternatives

1. Use Iroha 1 approach with roles and grantable permissions:
   1. `+` Out-of-the-Box permissions grouping by roles
   2.  `-` hardcoded permissions checks and additional low-level logic
2. Use assets, but do hardcoded permissions checks inside instructions
   1. `+` less client-side actions needed
   2. `-` no ability to clean genesis block  processing and configuration

Concerns

• Additional requirements to Iroha Special Instructions, Queries and Triggers will slow down development
• Additional high-level functionality would be needed to simulate "Roles"

Assumptions

• Iroha Triggers support pre-instruction hooks because it will be more effective to check permissions before instructions execution

Risks

• This solution will impact Iroha Triggers design `[9;6]`

Additional Information