community
/
dns
3
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix off-by-one error parsing DSA public key 

I ran into a slice bounds out of range panic. Tired so I just rewrote it.
This commit is contained in:
Andrew Tunnell-Jones 2014-11-01 10:54:01 +00:00
parent 6bbae6c6ea
commit 5bccac1c47
1 changed files with 12 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
dnssec.go
View File

@ -547,20 +547,22 @@ func (k *DNSKEY) publicKeyDSA() *dsa.PublicKey {
if err != nil {
return nil
}
if len(keybuf) < 22 { // TODO: check
if len(keybuf) < 22 {
return nil
}
t := int(keybuf[0])
t, keybuf := int(keybuf[0]), keybuf[1:]
size := 64 + t*8
q, keybuf := keybuf[:20], keybuf[20:]
if len(keybuf) != 3*size {
return nil
}
p, keybuf := keybuf[:size], keybuf[size:]
g, y := keybuf[:size], keybuf[size:]
pubkey := new(dsa.PublicKey)
pubkey.Parameters.Q = big.NewInt(0)
pubkey.Parameters.Q.SetBytes(keybuf[1:21]) // +/- 1 ?
pubkey.Parameters.P = big.NewInt(0)
pubkey.Parameters.P.SetBytes(keybuf[22 : 22+size])
pubkey.Parameters.G = big.NewInt(0)
pubkey.Parameters.G.SetBytes(keybuf[22+size+1 : 22+size*2])
pubkey.Y = big.NewInt(0)
pubkey.Y.SetBytes(keybuf[22+size*2+1 : 22+size*3])
pubkey.Parameters.Q = big.NewInt(0).SetBytes(q)
pubkey.Parameters.P = big.NewInt(0).SetBytes(p)
pubkey.Parameters.G = big.NewInt(0).SetBytes(g)
pubkey.Y = big.NewInt(0).SetBytes(y)
return pubkey
}