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feat: Allow to restrict MintCoins from app.go (cosmos#10771)
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## Description

Closes: cosmos#10386

This PR adds feature to the bank module so that other modules using bankKeeper would be able to call the keeper with restricted permissions when minting coins. `WithMintCoinsRestriction` would be able to get called within app.go when setting keeper components for each individual keeper, taking a function that would validate minting denom as an argument.

The example below demonstrates adding bank module with restricted permissions.
```
	app.DistrKeeper = distrkeeper.NewKeeper(
		appCodec, keys[distrtypes.StoreKey], app.GetSubspace(distrtypes.ModuleName), app.AccountKeeper, app.BankKeeper.WithMintCoinsRestriction(DistributionMintingRestriction),
		&stakingKeeper, authtypes.FeeCollectorName, app.ModuleAccountAddrs(),
	)
```
while there would be a seperate function that would restrict and validate allowed denoms as such.

```

func DistributionMintingRestriction(ctx sdk.Context, coins sdk.Coins) errors {
  for _, coin := range coins {
    if coin.Denom != ctx.NativeStakingDenom {
       return errors.New(fmt.Sprintf("Distribution can only print denom %s, tried minting %s", ctx.NativeStakingDenom, coin.Denom))
     }
  }
}
```

The sdk's simapp currently does not have any keepers that are to be changed with this implementation added, thus remaining unchanged in `app.go`.







---

### Author Checklist

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please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)
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mattverse authored Feb 18, 2022
1 parent 24e5a0d commit ea67659
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4 changes: 4 additions & 0 deletions CHANGELOG.md
Original file line number Diff line number Diff line change
Expand Up @@ -123,10 +123,14 @@ Ref: https://keepachangelog.com/en/1.0.0/
* [\#10748](https://github.com/cosmos/cosmos-sdk/pull/10748) Move legacy `x/gov` api to `v1beta1` directory.
* [\#10816](https://github.com/cosmos/cosmos-sdk/pull/10816) Reuse blocked addresses from the bank module. No need to pass them to distribution.
* [\#10852](https://github.com/cosmos/cosmos-sdk/pull/10852) Move `x/gov/types` to `x/gov/types/v1beta2`.
* [\#10922](https://github.com/cosmos/cosmos-sdk/pull/10922), [/#10957](https://github.com/cosmos/cosmos-sdk/pull/10957) Move key `server.Generate*` functions to testutil and support custom mnemonics in in-process testing network. Moved `TestMnemonic` from `testutil` package to `testdata`.
* (x/bank) [\#10771](https://github.com/cosmos/cosmos-sdk/pull/10771) Add safety check on bank module perms to allow module-specific mint restrictions (e.g. only minting a certain denom).* (x/bank) [\#10771](https://github.com/cosmos/cosmos-sdk/pull/10771) Add `bank.BaseKeeper.WithMintCoinsRestriction` function to restrict use of bank `MintCoins` usage.
* [\#10868](https://github.com/cosmos/cosmos-sdk/pull/10868), [\#10989](https://github.com/cosmos/cosmos-sdk/pull/10989) The Gov keeper accepts now 2 more mandatory arguments, the ServiceMsgRouter and a maximum proposal metadata length.
* [\#10868](https://github.com/cosmos/cosmos-sdk/pull/10868), [\#10989](https://github.com/cosmos/cosmos-sdk/pull/10989), [\#11093](https://github.com/cosmos/cosmos-sdk/pull/11093) The Gov keeper accepts now 2 more mandatory arguments, the ServiceMsgRouter and a gov Config including the max metadata length.
* [\#11124](https://github.com/cosmos/cosmos-sdk/pull/11124) Add `GetAllVersions` to application store
* (x/authz) [\#10447](https://github.com/cosmos/cosmos-sdk/pull/10447) authz `NewGrant` takes a new argument: block time, to correctly validate expire time.


### Client Breaking Changes

* [\#11089](https://github.com/cosmos/cosmos-sdk/pull/11089]) interacting with the node through `grpc.Dial` requires clients to pass a codec refer to [doc](docs/run-node/interact-node.md).
Expand Down
50 changes: 40 additions & 10 deletions x/bank/keeper/keeper.go
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ var _ Keeper = (*BaseKeeper)(nil)
// between accounts.
type Keeper interface {
SendKeeper
WithMintCoinsRestriction(MintingRestrictionFn) BaseKeeper

InitGenesis(sdk.Context, *types.GenesisState)
ExportGenesis(sdk.Context) *types.GenesisState
Expand Down Expand Up @@ -52,12 +53,15 @@ type Keeper interface {
type BaseKeeper struct {
BaseSendKeeper

ak types.AccountKeeper
cdc codec.BinaryCodec
storeKey storetypes.StoreKey
paramSpace paramtypes.Subspace
ak types.AccountKeeper
cdc codec.BinaryCodec
storeKey storetypes.StoreKey
paramSpace paramtypes.Subspace
mintCoinsRestrictionFn MintingRestrictionFn
}

type MintingRestrictionFn func(ctx sdk.Context, coins sdk.Coins) error

// GetPaginatedTotalSupply queries for the supply, ignoring 0 coins, with a given pagination
func (k BaseKeeper) GetPaginatedTotalSupply(ctx sdk.Context, pagination *query.PageRequest) (sdk.Coins, *query.PageResponse, error) {
store := ctx.KVStore(k.storeKey)
Expand Down Expand Up @@ -103,12 +107,33 @@ func NewBaseKeeper(
}

return BaseKeeper{
BaseSendKeeper: NewBaseSendKeeper(cdc, storeKey, ak, paramSpace, blockedAddrs),
ak: ak,
cdc: cdc,
storeKey: storeKey,
paramSpace: paramSpace,
BaseSendKeeper: NewBaseSendKeeper(cdc, storeKey, ak, paramSpace, blockedAddrs),
ak: ak,
cdc: cdc,
storeKey: storeKey,
paramSpace: paramSpace,
mintCoinsRestrictionFn: func(ctx sdk.Context, coins sdk.Coins) error { return nil },
}
}

// WithMintCoinsRestriction restricts the bank Keeper used within a specific module to
// have restricted permissions on minting via function passed in parameter.
// Previous restriction functions can be nested as such:
// bankKeeper.WithMintCoinsRestriction(restriction1).WithMintCoinsRestriction(restriction2)
func (k BaseKeeper) WithMintCoinsRestriction(check MintingRestrictionFn) BaseKeeper {
oldRestrictionFn := k.mintCoinsRestrictionFn
k.mintCoinsRestrictionFn = func(ctx sdk.Context, coins sdk.Coins) error {
err := check(ctx, coins)
if err != nil {
return err
}
err = oldRestrictionFn(ctx, coins)
if err != nil {
return err
}
return nil
}
return k
}

// DelegateCoins performs delegation by deducting amt coins from an account with
Expand Down Expand Up @@ -380,6 +405,11 @@ func (k BaseKeeper) UndelegateCoinsFromModuleToAccount(
// MintCoins creates new coins from thin air and adds it to the module account.
// It will panic if the module account does not exist or is unauthorized.
func (k BaseKeeper) MintCoins(ctx sdk.Context, moduleName string, amounts sdk.Coins) error {
err := k.mintCoinsRestrictionFn(ctx, amounts)
if err != nil {
ctx.Logger().Error(fmt.Sprintf("Module %q attempted to mint coins %s it doesn't have permission for, error %v", moduleName, amounts, err))
return err
}
acc := k.ak.GetModuleAccount(ctx, moduleName)
if acc == nil {
panic(sdkerrors.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", moduleName))
Expand All @@ -389,7 +419,7 @@ func (k BaseKeeper) MintCoins(ctx sdk.Context, moduleName string, amounts sdk.Co
panic(sdkerrors.Wrapf(sdkerrors.ErrUnauthorized, "module account %s does not have permissions to mint tokens", moduleName))
}

err := k.addCoins(ctx, acc.GetAddress(), amounts)
err = k.addCoins(ctx, acc.GetAddress(), amounts)
if err != nil {
return err
}
Expand Down
71 changes: 71 additions & 0 deletions x/bank/keeper/keeper_test.go
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
package keeper_test

import (
"fmt"
"testing"
"time"

Expand Down Expand Up @@ -1167,6 +1168,76 @@ func (suite *IntegrationTestSuite) getTestMetadata() []types.Metadata {
}
}

func (suite *IntegrationTestSuite) TestMintCoinRestrictions() {
type BankMintingRestrictionFn func(ctx sdk.Context, coins sdk.Coins) error

maccPerms := simapp.GetMaccPerms()
maccPerms[multiPerm] = []string{authtypes.Burner, authtypes.Minter, authtypes.Staking}

suite.app.AccountKeeper = authkeeper.NewAccountKeeper(
suite.app.AppCodec(), suite.app.GetKey(authtypes.StoreKey), suite.app.GetSubspace(authtypes.ModuleName),
authtypes.ProtoBaseAccount, maccPerms, sdk.Bech32MainPrefix,
)
suite.app.AccountKeeper.SetModuleAccount(suite.ctx, multiPermAcc)

type testCase struct {
coinsToTry sdk.Coin
expectPass bool
}

tests := []struct {
name string
restrictionFn BankMintingRestrictionFn
testCases []testCase
}{
{
"restriction",
func(ctx sdk.Context, coins sdk.Coins) error {
for _, coin := range coins {
if coin.Denom != fooDenom {
return fmt.Errorf("Module %s only has perms for minting %s coins, tried minting %s coins", types.ModuleName, fooDenom, coin.Denom)
}
}
return nil
},
[]testCase{
{
coinsToTry: newFooCoin(100),
expectPass: true,
},
{
coinsToTry: newBarCoin(100),
expectPass: false,
},
},
},
}

for _, test := range tests {
suite.app.BankKeeper = keeper.NewBaseKeeper(suite.app.AppCodec(), suite.app.GetKey(types.StoreKey),
suite.app.AccountKeeper, suite.app.GetSubspace(types.ModuleName), nil).WithMintCoinsRestriction(keeper.MintingRestrictionFn(test.restrictionFn))
for _, testCase := range test.testCases {
if testCase.expectPass {
suite.Require().NoError(
suite.app.BankKeeper.MintCoins(
suite.ctx,
multiPermAcc.Name,
sdk.NewCoins(testCase.coinsToTry),
),
)
} else {
suite.Require().Error(
suite.app.BankKeeper.MintCoins(
suite.ctx,
multiPermAcc.Name,
sdk.NewCoins(testCase.coinsToTry),
),
)
}
}
}
}

func TestKeeperTestSuite(t *testing.T) {
suite.Run(t, new(IntegrationTestSuite))
}
3 changes: 3 additions & 0 deletions x/bank/spec/02_keepers.md
Original file line number Diff line number Diff line change
Expand Up @@ -54,11 +54,14 @@ message Output {

The base keeper provides full-permission access: the ability to arbitrary modify any account's balance and mint or burn coins.

Restricted permission to mint per module could be achieved by using baseKeeper with `WithMintCoinsRestriction` to give specific restrictions to mint (e.g. only minting certain denom).

```go
// Keeper defines a module interface that facilitates the transfer of coins
// between accounts.
type Keeper interface {
SendKeeper
WithMintCoinsRestriction(NewRestrictionFn BankMintingRestrictionFn) BaseKeeper

InitGenesis(sdk.Context, *types.GenesisState)
ExportGenesis(sdk.Context) *types.GenesisState
Expand Down

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