trie: reject deletions when verifying range proofs

[karalabe]

Reject trie range proofs if they contain deletions, otherwise these would be noop entries that just bloat the response and may potentially cause trouble down the line since a semi-invalid proof passes verification.

[holiman]

LGTM

[holiman]

len(keys) == len(values), so you could use the same loop, with a slight modification

Suggested change

	// Ensure the received batch is monotonic increasing and contains no deletions
	for i := 0; i < len(keys)-1; i++ {
	if bytes.Compare(keys[i], keys[i+1]) >= 0 {
	return false, errors.New("range is not monotonically increasing")
	}
	}
	for _, value := range values {
	if len(value) == 0 {
	return false, errors.New("range contains deletion")
	}
	}
	// Ensure the received batch is monotonic increasing and contains no deletions
	for i := 0; i < len(keys); i++ {
	if i > 0 && bytes.Compare(keys[i-1], keys[i]) >= 0 {
	return false, errors.New("range is not monotonically increasing")
	}
	if len(values[i]) == 0 {
	return false, errors.New("range contains deletion")
	}
	}

Feel free to ignore

[fjl]

👍

[karalabe]

It did occur to me, but the off by one and extra clause check seemed wonky. The code is cleaner this way, we're not saving anything by optimizing out an extra addition per array item. Unless you guys feel very strongly, I'd leave it as is.