From c686634819861fdc07947171c5db1200a0134a10 Mon Sep 17 00:00:00 2001
From: Julien Robert <julien@rbrt.fr>
Date: Fri, 25 Feb 2022 11:37:53 +0100
Subject: [PATCH] fix(crypto): Multisig verification doesn't work for multisig
 sizes of multiples of 8 (#11142)

## Description

Closes: #9914



`NumTrueBitsBefore` was getting out of bound and panicking.

---

### 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
- [ ] 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/master/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/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
- [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)
---
 crypto/keys/multisig/multisig_test.go  | 2 +-
 crypto/types/compact_bit_array.go      | 4 +++-
 crypto/types/compact_bit_array_test.go | 1 +
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/crypto/keys/multisig/multisig_test.go b/crypto/keys/multisig/multisig_test.go
index 433776a6e4..1fc16893eb 100644
--- a/crypto/keys/multisig/multisig_test.go
+++ b/crypto/keys/multisig/multisig_test.go
@@ -124,7 +124,7 @@ func TestVerifyMultisignature(t *testing.T) {
 			func(require *require.Assertions) {
 				k := 2
 				signingIndices := []int{0, 3, 1}
-				pubKeys, sigs := generatePubKeysAndSignatures(5, msg)
+				pubKeys, sigs := generatePubKeysAndSignatures(8, msg)
 				pk = kmultisig.NewLegacyAminoPubKey(k, pubKeys)
 				sig = multisig.NewMultisig(len(pubKeys))
 				signBytesFn := func(mode signing.SignMode) ([]byte, error) { return msg, nil }
diff --git a/crypto/types/compact_bit_array.go b/crypto/types/compact_bit_array.go
index 1bbd5ec07d..741509f775 100644
--- a/crypto/types/compact_bit_array.go
+++ b/crypto/types/compact_bit_array.go
@@ -92,13 +92,15 @@ func (bA *CompactBitArray) NumTrueBitsBefore(index int) int {
 		index = max
 	}
 	// below we iterate over the bytes then over bits (in low endian) and count bits set to 1
-	for elem := 0; ; elem++ {
+	for elem := 0; elem < len(bA.Elems); elem++ {
 		if elem*8+7 >= index {
 			onesCount += bits.OnesCount8(bA.Elems[elem] >> (7 - (index % 8) + 1))
 			return onesCount
 		}
 		onesCount += bits.OnesCount8(bA.Elems[elem])
 	}
+
+	return onesCount
 }
 
 // Copy returns a copy of the provided bit array.
diff --git a/crypto/types/compact_bit_array_test.go b/crypto/types/compact_bit_array_test.go
index 11984729ac..1a76d45313 100644
--- a/crypto/types/compact_bit_array_test.go
+++ b/crypto/types/compact_bit_array_test.go
@@ -205,6 +205,7 @@ func TestCompactBitArrayNumOfTrueBitsBefore(t *testing.T) {
 		{`"x"`, []int{0}, []int{0}},
 		{`"_x"`, []int{1}, []int{0}},
 		{`"x___xxxx"`, []int{0, 4, 5, 6, 7}, []int{0, 1, 2, 3, 4}},
+		{`"x___xxxx"`, []int{0, 4, 5, 6, 7, 8}, []int{0, 1, 2, 3, 4, 5}},
 		{`"__x_xx_x__x_x___"`, []int{2, 4, 5, 7, 10, 12}, []int{0, 1, 2, 3, 4, 5}},
 		{`"______________xx"`, []int{14, 15}, []int{0, 1}},
 	}