286 lines
8.5 KiB
Go
286 lines
8.5 KiB
Go
package guardiand
|
||
|
||
import (
|
||
"fmt"
|
||
"strings"
|
||
)
|
||
|
||
// TODO(cpatrick): replace this whole file with just "github.com/cosmos/cosmos-sdk/types"
|
||
// This is added to avoid changing go.mod for guardiand for now.
|
||
|
||
// The code in this file was faithfully copied from: https://github.com/scrtlabs/btcutil/blob/master/bech32/bech32.go
|
||
// The code in this "bech32.go" file, and only this file, has the following license:
|
||
/*
|
||
ISC License
|
||
|
||
Copyright (c) 2013-2017 The btcsuite developers
|
||
Copyright (c) 2016-2017 The Lightning Network Developers
|
||
|
||
Permission to use, copy, modify, and distribute this software for any
|
||
purpose with or without fee is hereby granted, provided that the above
|
||
copyright notice and this permission notice appear in all copies.
|
||
|
||
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
||
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
||
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
|
||
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
||
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
||
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
|
||
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
||
*/
|
||
|
||
// toChars converts the byte slice 'data' to a string where each byte in 'data'
|
||
// encodes the index of a character in 'charset'.
|
||
func toChars(data []byte) (string, error) {
|
||
result := make([]byte, 0, len(data))
|
||
for _, b := range data {
|
||
if int(b) >= len(charset) {
|
||
return "", fmt.Errorf("invalid data byte: %v", b)
|
||
}
|
||
result = append(result, charset[b])
|
||
}
|
||
return string(result), nil
|
||
}
|
||
|
||
// For more details on the checksum calculation, please refer to BIP 173.
|
||
func bech32Checksum(hrp string, data []byte) []byte {
|
||
// Convert the bytes to list of integers, as this is needed for the
|
||
// checksum calculation.
|
||
integers := make([]int, len(data))
|
||
for i, b := range data {
|
||
integers[i] = int(b)
|
||
}
|
||
values := append(bech32HrpExpand(hrp), integers...)
|
||
values = append(values, []int{0, 0, 0, 0, 0, 0}...)
|
||
polymod := bech32Polymod(values) ^ 1
|
||
var res []byte
|
||
for i := 0; i < 6; i++ {
|
||
res = append(res, byte((polymod>>uint(5*(5-i)))&31))
|
||
}
|
||
return res
|
||
}
|
||
|
||
// For more details on the polymod calculation, please refer to BIP 173.
|
||
func bech32Polymod(values []int) int {
|
||
chk := 1
|
||
for _, v := range values {
|
||
b := chk >> 25
|
||
chk = (chk&0x1ffffff)<<5 ^ v
|
||
for i := 0; i < 5; i++ {
|
||
if (b>>uint(i))&1 == 1 {
|
||
chk ^= gen[i]
|
||
}
|
||
}
|
||
}
|
||
return chk
|
||
}
|
||
|
||
// For more details on HRP expansion, please refer to BIP 173.
|
||
func bech32HrpExpand(hrp string) []int {
|
||
v := make([]int, 0, len(hrp)*2+1)
|
||
for i := 0; i < len(hrp); i++ {
|
||
v = append(v, int(hrp[i]>>5))
|
||
}
|
||
v = append(v, 0)
|
||
for i := 0; i < len(hrp); i++ {
|
||
v = append(v, int(hrp[i]&31))
|
||
}
|
||
return v
|
||
}
|
||
|
||
// For more details on the checksum verification, please refer to BIP 173.
|
||
func bech32VerifyChecksum(hrp string, data []byte) bool {
|
||
integers := make([]int, len(data))
|
||
for i, b := range data {
|
||
integers[i] = int(b)
|
||
}
|
||
concat := append(bech32HrpExpand(hrp), integers...)
|
||
return bech32Polymod(concat) == 1
|
||
}
|
||
|
||
// toBytes converts each character in the string 'chars' to the value of the
|
||
// index of the correspoding character in 'charset'.
|
||
func toBytes(chars string) ([]byte, error) {
|
||
decoded := make([]byte, 0, len(chars))
|
||
for i := 0; i < len(chars); i++ {
|
||
index := strings.IndexByte(charset, chars[i])
|
||
if index < 0 {
|
||
return nil, fmt.Errorf("invalid character not part of "+
|
||
"charset: %v", chars[i])
|
||
}
|
||
decoded = append(decoded, byte(index))
|
||
}
|
||
return decoded, nil
|
||
}
|
||
|
||
const charset = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
|
||
|
||
var gen = []int{0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3}
|
||
|
||
// Decode decodes a bech32 encoded string, returning the human-readable
|
||
// part and the data part excluding the checksum.
|
||
func decode(bech string, limit int) (string, []byte, error) {
|
||
// The maximum allowed length for a bech32 string is 90. It must also
|
||
// be at least 8 characters, since it needs a non-empty HRP, a
|
||
// separator, and a 6 character checksum.
|
||
if len(bech) < 8 || len(bech) > limit {
|
||
return "", nil, fmt.Errorf("invalid bech32 string length %d",
|
||
len(bech))
|
||
}
|
||
// Only ASCII characters between 33 and 126 are allowed.
|
||
for i := 0; i < len(bech); i++ {
|
||
if bech[i] < 33 || bech[i] > 126 {
|
||
return "", nil, fmt.Errorf("invalid character in "+
|
||
"string: '%c'", bech[i])
|
||
}
|
||
}
|
||
|
||
// The characters must be either all lowercase or all uppercase.
|
||
lower := strings.ToLower(bech)
|
||
upper := strings.ToUpper(bech)
|
||
if bech != lower && bech != upper {
|
||
return "", nil, fmt.Errorf("string not all lowercase or all " +
|
||
"uppercase")
|
||
}
|
||
|
||
// We'll work with the lowercase string from now on.
|
||
bech = lower
|
||
|
||
// The string is invalid if the last '1' is non-existent, it is the
|
||
// first character of the string (no human-readable part) or one of the
|
||
// last 6 characters of the string (since checksum cannot contain '1'),
|
||
// or if the string is more than 90 characters in total.
|
||
one := strings.LastIndexByte(bech, '1')
|
||
if one < 1 || one+7 > len(bech) {
|
||
return "", nil, fmt.Errorf("invalid index of 1")
|
||
}
|
||
|
||
// The human-readable part is everything before the last '1'.
|
||
hrp := bech[:one]
|
||
data := bech[one+1:]
|
||
|
||
// Each character corresponds to the byte with value of the index in
|
||
// 'charset'.
|
||
decoded, err := toBytes(data)
|
||
if err != nil {
|
||
return "", nil, fmt.Errorf("failed converting data to bytes: "+
|
||
"%v", err)
|
||
}
|
||
|
||
if !bech32VerifyChecksum(hrp, decoded) {
|
||
moreInfo := ""
|
||
checksum := bech[len(bech)-6:]
|
||
expected, err := toChars(bech32Checksum(hrp,
|
||
decoded[:len(decoded)-6]))
|
||
if err == nil {
|
||
moreInfo = fmt.Sprintf("Expected %v, got %v.",
|
||
expected, checksum)
|
||
}
|
||
return "", nil, fmt.Errorf("checksum failed. " + moreInfo)
|
||
}
|
||
|
||
// We exclude the last 6 bytes, which is the checksum.
|
||
return hrp, decoded[:len(decoded)-6], nil
|
||
}
|
||
|
||
func decodeAndConvert(bech string) (string, []byte, error) {
|
||
hrp, data, err := decode(bech, 1023)
|
||
if err != nil {
|
||
return "", nil, fmt.Errorf("decoding bech32 failed: %w", err)
|
||
}
|
||
|
||
converted, err := convertBits(data, 5, 8, false)
|
||
if err != nil {
|
||
return "", nil, fmt.Errorf("decoding bech32 failed: %w", err)
|
||
}
|
||
|
||
return hrp, converted, nil
|
||
}
|
||
|
||
// ConvertBits converts a byte slice where each byte is encoding fromBits bits,
|
||
// to a byte slice where each byte is encoding toBits bits.
|
||
func convertBits(data []byte, fromBits, toBits uint8, pad bool) ([]byte, error) {
|
||
if fromBits < 1 || fromBits > 8 || toBits < 1 || toBits > 8 {
|
||
return nil, fmt.Errorf("only bit groups between 1 and 8 allowed")
|
||
}
|
||
|
||
// The final bytes, each byte encoding toBits bits.
|
||
var regrouped []byte
|
||
|
||
// Keep track of the next byte we create and how many bits we have
|
||
// added to it out of the toBits goal.
|
||
nextByte := byte(0)
|
||
filledBits := uint8(0)
|
||
|
||
for _, b := range data {
|
||
|
||
// Discard unused bits.
|
||
b = b << (8 - fromBits)
|
||
|
||
// How many bits remaining to extract from the input data.
|
||
remFromBits := fromBits
|
||
for remFromBits > 0 {
|
||
// How many bits remaining to be added to the next byte.
|
||
remToBits := toBits - filledBits
|
||
|
||
// The number of bytes to next extract is the minimum of
|
||
// remFromBits and remToBits.
|
||
toExtract := remFromBits
|
||
if remToBits < toExtract {
|
||
toExtract = remToBits
|
||
}
|
||
|
||
// Add the next bits to nextByte, shifting the already
|
||
// added bits to the left.
|
||
nextByte = (nextByte << toExtract) | (b >> (8 - toExtract))
|
||
|
||
// Discard the bits we just extracted and get ready for
|
||
// next iteration.
|
||
b = b << toExtract
|
||
remFromBits -= toExtract
|
||
filledBits += toExtract
|
||
|
||
// If the nextByte is completely filled, we add it to
|
||
// our regrouped bytes and start on the next byte.
|
||
if filledBits == toBits {
|
||
regrouped = append(regrouped, nextByte)
|
||
filledBits = 0
|
||
nextByte = 0
|
||
}
|
||
}
|
||
}
|
||
|
||
// We pad any unfinished group if specified.
|
||
if pad && filledBits > 0 {
|
||
nextByte = nextByte << (toBits - filledBits)
|
||
regrouped = append(regrouped, nextByte)
|
||
filledBits = 0
|
||
nextByte = 0
|
||
}
|
||
|
||
// Any incomplete group must be <= 4 bits, and all zeroes.
|
||
if filledBits > 0 && (filledBits > 4 || nextByte != 0) {
|
||
return nil, fmt.Errorf("invalid incomplete group")
|
||
}
|
||
|
||
return regrouped, nil
|
||
}
|
||
|
||
// GetFromBech32 decodes a bytestring from a Bech32 encoded string.
|
||
func getFromBech32(bech32str, prefix string) ([]byte, error) {
|
||
if len(bech32str) == 0 {
|
||
return nil, fmt.Errorf("zero length bech32 address")
|
||
}
|
||
|
||
hrp, bz, err := decodeAndConvert(bech32str)
|
||
if err != nil {
|
||
return nil, err
|
||
}
|
||
|
||
if hrp != prefix {
|
||
return nil, fmt.Errorf("invalid Bech32 prefix; expected %s, got %s", prefix, hrp)
|
||
}
|
||
|
||
return bz, nil
|
||
}
|