fix: decrement types.Dec max length to keep decimal bits in DecimalPr…

…ecisionBits (#11772)

## Description

Closes: #11732

As found by OSS-Fuzz, large numbers may overflow the current maxDecBitLen because
it assumes that DecimalPrecisionBits (60) can always be represented by Precision (18)
base-10 digits. Since 2^60 is larger than 2^18, this assumption is false.

This change fixes #11732 by only allowing 59 bits of precision on top of the 256
maxBitLen allowed for the integer part.

---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

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

(cherry picked from commit f9913c1)

# Conflicts:
#	CHANGELOG.md

CHANGELOG.md

@@ -46,6 +46,45 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+<<<<<<< HEAD
+=======
+* [\#11696](https://github.com/cosmos/cosmos-sdk/pull/11696) Rename `helpers.GenTx` to `GenSignedMockTx` to avoid confusion with genutil's `GenTxCmd`.
+* (x/auth/vesting) [\#11652](https://github.com/cosmos/cosmos-sdk/pull/11652) Add util functions for `Period(s)`
+* [\#11630](https://github.com/cosmos/cosmos-sdk/pull/11630) Add SafeSub method to sdk.Coin.
+* [\#11511](https://github.com/cosmos/cosmos-sdk/pull/11511) Add api server flags to start command.
+* [\#11484](https://github.com/cosmos/cosmos-sdk/pull/11484) Implement getter for keyring backend option.
+* [\#11449](https://github.com/cosmos/cosmos-sdk/pull/11449) Improved error messages when node isn't synced.
+* [\#11349](https://github.com/cosmos/cosmos-sdk/pull/11349) Add `RegisterAminoMsg` function that checks that a msg name is <40 chars (else this would break ledger nano signing) then registers the concrete msg type with amino, it should be used for registering `sdk.Msg`s with amino instead of `cdc.RegisterConcrete`.
+* [\#11089](https://github.com/cosmos/cosmos-sdk/pull/11089]) Now cosmos-sdk consumers can upgrade gRPC to its newest versions.
+* [\#10439](https://github.com/cosmos/cosmos-sdk/pull/10439) Check error for `RegisterQueryHandlerClient` in all modules `RegisterGRPCGatewayRoutes`.
+* [\#9780](https://github.com/cosmos/cosmos-sdk/pull/9780) Remove gogoproto `moretags` YAML annotations and add `sigs.k8s.io/yaml` for YAML marshalling.
+* (x/bank) [\#10134](https://github.com/cosmos/cosmos-sdk/pull/10134) Add `HasDenomMetadata` function to bank `Keeper` to check if a client coin denom metadata exists in state.
+* (x/bank) [\#10022](https://github.com/cosmos/cosmos-sdk/pull/10022) `BankKeeper.SendCoins` now takes less execution time.
+* (deps) [\#9987](https://github.com/cosmos/cosmos-sdk/pull/9987) Bump Go version minimum requirement to `1.17`
+* (cli) [\#9856](https://github.com/cosmos/cosmos-sdk/pull/9856) Overwrite `--sequence` and `--account-number` flags with default flag values when used with `offline=false` in `sign-batch` command.
+* (rosetta) [\#10001](https://github.com/cosmos/cosmos-sdk/issues/10001) Add documentation for rosetta-cli dockerfile and rename folder for the rosetta-ci dockerfile
+* [\#9699](https://github.com/cosmos/cosmos-sdk/pull/9699) Add `:`, `.`, `-`, and `_` as allowed characters in the default denom regular expression.
+* (genesis) [\#9697](https://github.com/cosmos/cosmos-sdk/pull/9697) Ensure `InitGenesis` returns with non-empty validator set.
+* [\#10341](https://github.com/cosmos/cosmos-sdk/pull/10341) Move from `io/ioutil` to `io` and `os` packages.
+* [\#10468](https://github.com/cosmos/cosmos-sdk/pull/10468) Allow futureOps to queue additional operations in simulations
+* [\#10625](https://github.com/cosmos/cosmos-sdk/pull/10625) Add `--fee-payer` CLI flag
+* (cli) [\#10683](https://github.com/cosmos/cosmos-sdk/pull/10683) In CLI, allow 1 SIGN_MODE_DIRECT signer in transactions with multiple signers.
+* (deps) [\#10210](https://github.com/cosmos/cosmos-sdk/pull/10210) Bump Tendermint to [v0.35.0](https://github.com/tendermint/tendermint/releases/tag/v0.35.0).
+* (deps) [\#10706](https://github.com/cosmos/cosmos-sdk/issues/10706) Bump rosetta-sdk-go to v0.7.2 and rosetta-cli to v0.7.3
+* (types/errors) [\#10779](https://github.com/cosmos/cosmos-sdk/pull/10779) Move most functionality in `types/errors` to a standalone `errors` go module, except the `RootCodespace` errors and ABCI response helpers. All functions and types that used to live in `types/errors` are now aliased so this is not a breaking change.
+* (gov) [\#10854](https://github.com/cosmos/cosmos-sdk/pull/10854) v1beta2's vote doesn't include the deprecate `option VoteOption` anymore. Instead, it only uses `WeightedVoteOption`.
+* (types) [\#11004](https://github.com/cosmos/cosmos-sdk/pull/11004) Added mutable versions of many of the sdk.Dec types operations.  This improves performance when used by avoiding reallocating a new bigint for each operation.
+* (x/auth) [\#10880](https://github.com/cosmos/cosmos-sdk/pull/10880) Added a new query to the tx query service that returns a block with transactions fully decoded.
+* (types) [\#11200](https://github.com/cosmos/cosmos-sdk/pull/11200) Added `Min()` and `Max()` operations on sdk.Coins.
+* (gov) [\#11287](https://github.com/cosmos/cosmos-sdk/pull/11287) Fix error message when no flags are provided while executing `submit-legacy-proposal` transaction.
+* (x/auth) [\#11482](https://github.com/cosmos/cosmos-sdk/pull/11482) Improve panic message when attempting to register a method handler for a message that does not implement sdk.Msg
+* (x/staking) [\#11596](https://github.com/cosmos/cosmos-sdk/pull/11596) Add (re)delegation getters
+
+### Bug Fixes
+
+* [\#11772](https://github.com/cosmos/cosmos-sdk/pull/11772) Limit types.Dec length to avoid overflow.
+* [\#11724](https://github.com/cosmos/cosmos-sdk/pull/11724) Fix data race issues with api.Server
+>>>>>>> f9913c139 (fix: decrement types.Dec max length to keep decimal bits in DecimalPrecisionBits (#11772))
 * [\#11693](https://github.com/cosmos/cosmos-sdk/pull/11693) Add validation for gentx cmd.
 * [\#11686](https://github.com/cosmos/cosmos-sdk/pull/11686) Update the min required Golang version to `1.17`.
 * (x/auth/vesting) [\#11652](https://github.com/cosmos/cosmos-sdk/pull/11652) Add util functions for `Period(s)`

types/coin_test.go

@@ -751,6 +751,7 @@ func (s *coinTestSuite) TestParseCoins() {
 		{"10atom10", true, sdk.Coins{{"atom10", sdk.NewInt(10)}}},
 		{"200transfer/channelToA/uatom", true, sdk.Coins{{"transfer/channelToA/uatom", sdk.NewInt(200)}}},
 		{"50ibc/7F1D3FCF4AE79E1554D670D1AD949A9BA4E4A3C76C63093E17E446A46061A7A2", true, sdk.Coins{{"ibc/7F1D3FCF4AE79E1554D670D1AD949A9BA4E4A3C76C63093E17E446A46061A7A2", sdk.NewInt(50)}}},
+		{"120000000000000000000000000000000000000000000000000000000000000000000000000000btc", false, nil},
 	}
 
 	for tcIndex, tc := range cases {

types/decimal.go

@@ -22,11 +22,16 @@ const (
 	// number of decimal places
 	Precision = 18
 
-	// bytes required to represent the above precision
-	// Ceiling[Log2[999 999 999 999 999 999]]
+	// bits required to represent the above precision
+	// Ceiling[Log2[10^Precision - 1]]
 	DecimalPrecisionBits = 60
 
-	maxDecBitLen = maxBitLen + DecimalPrecisionBits
+	// decimalTruncateBits is the minimum number of bits removed
+	// by a truncate operation. It is equal to
+	// Floor[Log2[10^Precision - 1]].
+	decimalTruncateBits = DecimalPrecisionBits - 1
+
+	maxDecBitLen = maxBitLen + decimalTruncateBits
 
 	// max number of iterations in ApproxRoot function
 	maxApproxRootIterations = 100

types/decimal_test.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"math/big"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/suite"
@@ -33,10 +34,10 @@ func (s *decimalTestSuite) TestNewDecFromStr() {
 	largeBigInt, ok := new(big.Int).SetString("3144605511029693144278234343371835", 10)
 	s.Require().True(ok)
 
-	largerBigInt, ok := new(big.Int).SetString("88888888888888888888888888888888888888888888888888888888888888888888844444440", 10)
+	largerBigInt, ok := new(big.Int).SetString("8888888888888888888888888888888888888888888888888888888888888888888844444440", 10)
 	s.Require().True(ok)
 
-	largestBigInt, ok := new(big.Int).SetString("133499189745056880149688856635597007162669032647290798121690100488888732861290034376435130433535", 10)
+	largestBigInt, ok := new(big.Int).SetString("33499189745056880149688856635597007162669032647290798121690100488888732861290034376435130433535", 10)
 	s.Require().True(ok)
 
 	tests := []struct {
@@ -63,8 +64,8 @@ func (s *decimalTestSuite) TestNewDecFromStr() {
 		{"foobar", true, sdk.Dec{}},
 		{"0.foobar", true, sdk.Dec{}},
 		{"0.foobar.", true, sdk.Dec{}},
-		{"88888888888888888888888888888888888888888888888888888888888888888888844444440", false, sdk.NewDecFromBigInt(largerBigInt)},
-		{"133499189745056880149688856635597007162669032647290798121690100488888732861290.034376435130433535", false, sdk.NewDecFromBigIntWithPrec(largestBigInt, 18)},
+		{"8888888888888888888888888888888888888888888888888888888888888888888844444440", false, sdk.NewDecFromBigInt(largerBigInt)},
+		{"33499189745056880149688856635597007162669032647290798121690100488888732861290.034376435130433535", false, sdk.NewDecFromBigIntWithPrec(largestBigInt, 18)},
 		{"133499189745056880149688856635597007162669032647290798121690100488888732861291", true, sdk.Dec{}},
 	}
 
@@ -449,10 +450,14 @@ func (s *decimalTestSuite) TestDecSortableBytes() {
 }
 
 func (s *decimalTestSuite) TestDecEncoding() {
-	largestBigInt, ok := new(big.Int).SetString("133499189745056880149688856635597007162669032647290798121690100488888732861290034376435130433535", 10)
+	largestBigInt, ok := new(big.Int).SetString("33499189745056880149688856635597007162669032647290798121690100488888732861290034376435130433535", 10)
 	s.Require().True(ok)
 
-	smallestBigInt, ok := new(big.Int).SetString("-133499189745056880149688856635597007162669032647290798121690100488888732861290034376435130433535", 10)
+	smallestBigInt, ok := new(big.Int).SetString("-33499189745056880149688856635597007162669032647290798121690100488888732861290034376435130433535", 10)
+	s.Require().True(ok)
+
+	const maxDecBitLen = 315
+	maxInt, ok := new(big.Int).SetString(strings.Repeat("1", maxDecBitLen), 2)
 	s.Require().True(ok)
 
 	testCases := []struct {
@@ -492,15 +497,21 @@ func (s *decimalTestSuite) TestDecEncoding() {
 		},
 		{
 			sdk.NewDecFromBigIntWithPrec(largestBigInt, 18),
-			"313333343939313839373435303536383830313439363838383536363335353937303037313632363639303332363437323930373938313231363930313030343838383838373332383631323930303334333736343335313330343333353335",
-			"\"133499189745056880149688856635597007162669032647290798121690100488888732861290.034376435130433535\"",
-			"\"133499189745056880149688856635597007162669032647290798121690100488888732861290.034376435130433535\"\n",
+			"3333343939313839373435303536383830313439363838383536363335353937303037313632363639303332363437323930373938313231363930313030343838383838373332383631323930303334333736343335313330343333353335",
+			"\"33499189745056880149688856635597007162669032647290798121690100488888732861290.034376435130433535\"",
+			"\"33499189745056880149688856635597007162669032647290798121690100488888732861290.034376435130433535\"\n",
 		},
 		{
 			sdk.NewDecFromBigIntWithPrec(smallestBigInt, 18),
-			"2D313333343939313839373435303536383830313439363838383536363335353937303037313632363639303332363437323930373938313231363930313030343838383838373332383631323930303334333736343335313330343333353335",
-			"\"-133499189745056880149688856635597007162669032647290798121690100488888732861290.034376435130433535\"",
-			"\"-133499189745056880149688856635597007162669032647290798121690100488888732861290.034376435130433535\"\n",
+			"2D3333343939313839373435303536383830313439363838383536363335353937303037313632363639303332363437323930373938313231363930313030343838383838373332383631323930303334333736343335313330343333353335",
+			"\"-33499189745056880149688856635597007162669032647290798121690100488888732861290.034376435130433535\"",
+			"\"-33499189745056880149688856635597007162669032647290798121690100488888732861290.034376435130433535\"\n",
+		},
+		{
+			sdk.NewDecFromBigIntWithPrec(maxInt, 18),
+			"3636373439353934383732353238343430303734383434343238333137373938353033353831333334353136333233363435333939303630383435303530323434343434333636343330363435303137313838323137353635323136373637",
+			"\"66749594872528440074844428317798503581334516323645399060845050244444366430645.017188217565216767\"",
+			"\"66749594872528440074844428317798503581334516323645399060845050244444366430645.017188217565216767\"\n",
 		},
 	}