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lnwire: fix bug in wire.OutPoint -> lnwire.ChannelID conversion

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This commit fixes an existing, unnoticed bug within the lnwire.
NewChanIDFromOutPoint function. Two lingering issues cause the function
to not do anything at all, meaning that the channel ID, would be the
exact same as the actual txid passed in.

The first issue was that the xorTxid function wasn’t actually XOR’ing
the last two bytes. This was due to the fact that the function wasn’t
taking a pointer to the target ChannelID, meaning that the mutation
wouldn’t be seen outside of the scope of the function. Second, we had
our slicing reversed, rather than buf[30:], we were using buf[:30],
meaning that we were weren’t properly filling the buffer with the lower
2-bytes of the passed index.
This commit is contained in:
Olaoluwa Osuntokun 2017-09-18 19:45:03 +02:00
parent b58ef85513
commit e3717485f5
No known key found for this signature in database
GPG Key ID: 964EA263DD637C21
1 changed files with 6 additions and 6 deletions
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12
lnwire/channel_id.go
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@ -41,7 +41,7 @@ func NewChanIDFromOutPoint(op *wire.OutPoint) ChannelID {
// With the txid copied over, we'll now XOR the lower 2-bytes of the
// partial channelID with big-endian serialization of output index.
xorTxid(cid, uint16(op.Index))
xorTxid(&cid, uint16(op.Index))
return cid
}
@ -49,12 +49,12 @@ func NewChanIDFromOutPoint(op *wire.OutPoint) ChannelID {
// xorTxid performs the transformation needed to transform an OutPoint into a
// ChannelID. To do this, we expect the cid parameter to contain the txid
// unaltered and the outputIndex to be the output index
func xorTxid(cid ChannelID, outputIndex uint16) {
func xorTxid(cid *ChannelID, outputIndex uint16) {
var buf [32]byte
binary.BigEndian.PutUint16(buf[:30], outputIndex)
binary.BigEndian.PutUint16(buf[30:], outputIndex)
buf[30] = cid[30] ^ buf[30]
buf[31] = cid[31] ^ buf[31]
cid[30] = cid[30] ^ buf[30]
cid[31] = cid[31] ^ buf[31]
}
// GenPossibleOutPoints generates all the possible outputs given a channel ID.
@ -65,7 +65,7 @@ func (c *ChannelID) GenPossibleOutPoints() [MaxFundingTxOutputs]wire.OutPoint {
var possiblePoints [MaxFundingTxOutputs]wire.OutPoint
for i := uint32(0); i < MaxFundingTxOutputs; i++ {
cidCopy := *c
xorTxid(cidCopy, uint16(i))
xorTxid(&cidCopy, uint16(i))
possiblePoints[i] = wire.OutPoint{
Hash: chainhash.Hash(cidCopy),