LBRYCommunity/lbcd
1
0
Fork 0
Code Issues 17 Pull requests 4 Projects Releases 28 Packages Wiki Activity

btcec/signature: moved minimum signature length to a constant

Browse source
This commit is contained in:
Julian Meyer 2018-09-20 20:19:11 -07:00
parent db8e412dc6
commit 8965887ca4
1 changed files with 7 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
btcec/signature.go
View file

@ -85,6 +85,11 @@ func (sig *Signature) IsEqual(otherSig *Signature) bool {
sig.S.Cmp(otherSig.S) == 0
}
// minSigLen is the minimum length of a DER encoded signature and is
// when both R and S are 1 byte each.
// 0x30 + <1-byte> + 0x02 + 0x01 + <byte> + 0x2 + 0x01 + <byte>
const minSigLen = 8
func parseSig(sigStr []byte, curve elliptic.Curve, der bool) (*Signature, error) {
// Originally this code used encoding/asn1 in order to parse the
// signature, but a number of problems were found with this approach.
@ -98,9 +103,7 @@ func parseSig(sigStr []byte, curve elliptic.Curve, der bool) (*Signature, error)
signature := &Signature{}
// minimal message is when both numbers are 1 bytes. adding up to:
// 0x30 + len + 0x02 + 0x01 + <byte> + 0x2 + 0x01 + <byte>
if len(sigStr) < 8 {
if len(sigStr) < minSigLen {
return nil, errors.New("malformed signature: too short")
}
// 0x30
@ -115,7 +118,7 @@ func parseSig(sigStr []byte, curve elliptic.Curve, der bool) (*Signature, error)
// siglen should be less than the entire message and greater than
// the minimal message of size 8.
if int(siglen+2) > len(sigStr) || int(siglen+2) < 8 {
if int(siglen+2) > len(sigStr) || int(siglen+2) < minSigLen {
return nil, errors.New("malformed signature: bad length")
}
// trim the slice we're working on so we only look at what matters.