crypto/types: CompactBitArray doesn't defensively check that .SetIndex has a positive index before indexing

[odeke-em]

Summary of Bug

If we audit this code

cosmos-sdk/crypto/types/compact_bit_array.go

Lines 55 to 71 in c4864e9

	func (bA *CompactBitArray) SetIndex(i int, v bool) bool {
	if bA == nil {
	return false
	}
	if i >= bA.Count() {
	return false
	}
	if v {
	bA.Elems[i>>3] |= (uint8(1) << uint8(7-(i%8)))
	} else {
	bA.Elems[i>>3] &= ^(uint8(1) << uint8(7-(i%8)))
	}
	return true
	}

we'll notice

cosmos-sdk/crypto/types/compact_bit_array.go

Lines 60 to 68 in c4864e9

	if i >= bA.Count() {
	return false
	}
	if v {
	bA.Elems[i>>3] |= (uint8(1) << uint8(7-(i%8)))
	} else {
	bA.Elems[i>>3] &= ^(uint8(1) << uint8(7-(i%8)))
	}

the code in (*CompactBitArray).SetIndex assumes that it'll always take in a positive index. However, the stakes have changed, the cosmos-sdk will be used in every way and our mandate is ensuring reliability and security. We have an explicit check in there that the index won't cause out of bounds, we should simply add one too to ensure that we don't accept negative values.

Version

Latest with bffcae5

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For Admin Use

• Not duplicate issue
• Appropriate labels applied
• Appropriate contributors tagged
• Contributor assigned/self-assigned

/cc @cuonglm