Permissionless token pools (#652)

This PR is mainly focussed on the CCIP side of self serve token pools.
Some additional contracts had to be written/changed, but in review,
please focus on the CCIP & token pool side of self serve, not on the
TokenAdminRegistry.

Considerations

- Token pools are now considered hostile
  - This goes for both in- and output
  - Source side
    - Call to `sourcePool.lockOrBurn` from the onRamp
- Does not strictly have to be through a callWithExactGas call, as CCIP
is not paying for gas used here
      - Same for return data bomb
      - It returns the destPool and optional extraData
- DestPool has to be checked for length to mitigate the risk of return
data bombs through this field
- Since the onRamp is EVM2EVM, we can assume the address is an
abi.encoded(address) and therefore 32 bytes
        - ExtraData is checked like it was before
  - Dest side
    - We used to make a call to `getToken`
- Since this would be a hostile call, and require the full
callWithExactGas protection, we opted to fold this getter into the
`releaseOrMint` call. This saves a significant amount of gas, and makes
sure we only have to do a single call to the hostile contract.
    - We call `releaseOrMint` on the `pool` provided on the source side
- The pool data is considered hostile, as it came from an untrusted
source
- We need to ensure the address is valid and it contains a contract
      - The releaseOrMint call was already done through callWithExactGas

This brings the number of onchain calls to token pools to 2 per
transferred token: one on the source chain and one on the destination.
This is the absolute minimum possible.


Reviews for this PR should focus on

- Hostile token pool interactions
  - DoS
  - Unusual reverts
  - Gas bombs
  - Return data bombs
- The changes to CCIP and their impact on the security and availability
of the protocol

Please do not focus on

- The TokenAdminRegistry, except for things that would impact the
changed CCIP design


# TODO

Onchain:
- Add the tag to the return data and check for it (next PR)
- Use default price for tokens that don't have a config (next PR)

Offchain
- Add 1.4 lane logic to integration test?

---------

Co-authored-by: Anindita Ghosh <[email protected]>

core/services/ocr2/plugins/ccip/abihelpers/abi_helpers.go

@@ -71,6 +71,10 @@ func EncodeAbiStruct[T AbiDefined](decoded T) ([]byte, error) {
 	return utils.ABIEncode(decoded.AbiString(), decoded)
 }
 
+func EncodeAddress(address common.Address) ([]byte, error) {
+	return utils.ABIEncode(`[{"type":"address"}]`, address)
+}
+
 func DecodeAbiStruct[T AbiDefinedValid](encoded []byte) (T, error) {
 	var empty T
 

core/services/ocr2/plugins/ccip/ccipexec/ocr2.go

@@ -815,13 +815,10 @@ func getTokensPrices(ctx context.Context, priceRegistry ccipdata.PriceRegistryRe
 	}
 
 	for i, token := range tokens {
-		// price of a token can never be zero
+		// Prices can be zero, as we only need prices for tokens that are part of the aggregate rate limiter.
+		// TODO CCIP-1986: check against a list of tokens that DO need prices in the offRamp and error if a price is missing.
 		if fetchedPrices[i].Value.BitLen() == 0 {
-			priceRegistryAddress, err := priceRegistry.Address(ctx)
-			if err != nil {
-				return nil, fmt.Errorf("get price registry address: %w", err)
-			}
-			return nil, fmt.Errorf("price of token %s is zero (price registry=%s)", token, priceRegistryAddress)
+			continue
 		}
 
 		// price registry should not report different price for the same token

core/services/ocr2/plugins/ccip/ccipexec/ocr2_test.go

@@ -1039,17 +1039,6 @@ func Test_getTokensPrices(t *testing.T) {
 			},
 			expErr: true,
 		},
-		{
-			name:      "zero price should lead to an error",
-			feeTokens: []cciptypes.Address{tk1, tk2},
-			tokens:    []cciptypes.Address{tk3},
-			retPrices: []cciptypes.TokenPriceUpdate{
-				{TokenPrice: cciptypes.TokenPrice{Value: big.NewInt(10)}},
-				{TokenPrice: cciptypes.TokenPrice{Value: big.NewInt(0)}},
-				{TokenPrice: cciptypes.TokenPrice{Value: big.NewInt(30)}},
-			},
-			expErr: true,
-		},
 		{
 			name:      "contract returns less prices than requested",
 			feeTokens: []cciptypes.Address{tk1, tk2},