mirror of
https://github.com/ergochat/ergo.git
synced 2024-11-22 11:59:40 +01:00
96 lines
2.6 KiB
Go
96 lines
2.6 KiB
Go
// Copyright (c) 2019 Shivaram Lingamneni
|
|
|
|
package cloaks
|
|
|
|
import (
|
|
"fmt"
|
|
"net"
|
|
|
|
"golang.org/x/crypto/sha3"
|
|
|
|
"github.com/ergochat/ergo/irc/utils"
|
|
)
|
|
|
|
type CloakConfig struct {
|
|
Enabled bool
|
|
EnabledForAlwaysOn bool `yaml:"enabled-for-always-on"`
|
|
Netname string
|
|
CidrLenIPv4 int `yaml:"cidr-len-ipv4"`
|
|
CidrLenIPv6 int `yaml:"cidr-len-ipv6"`
|
|
NumBits int `yaml:"num-bits"`
|
|
LegacySecretValue string `yaml:"secret"`
|
|
|
|
secret string
|
|
numBytes int
|
|
ipv4Mask net.IPMask
|
|
ipv6Mask net.IPMask
|
|
}
|
|
|
|
func (cloakConfig *CloakConfig) Initialize() {
|
|
// sanity checks:
|
|
numBits := cloakConfig.NumBits
|
|
if 0 == numBits {
|
|
numBits = 64
|
|
} else if 256 < numBits {
|
|
numBits = 256
|
|
}
|
|
|
|
// derived values:
|
|
cloakConfig.numBytes = numBits / 8
|
|
// round up to the nearest byte
|
|
if numBits%8 != 0 {
|
|
cloakConfig.numBytes += 1
|
|
}
|
|
cloakConfig.ipv4Mask = net.CIDRMask(cloakConfig.CidrLenIPv4, 32)
|
|
cloakConfig.ipv6Mask = net.CIDRMask(cloakConfig.CidrLenIPv6, 128)
|
|
}
|
|
|
|
func (cloakConfig *CloakConfig) SetSecret(secret string) {
|
|
cloakConfig.secret = secret
|
|
}
|
|
|
|
// simple cloaking algorithm: normalize the IP to its CIDR,
|
|
// then hash the resulting bytes with a secret key,
|
|
// then truncate to the desired length, b32encode, and append the fake TLD.
|
|
func (config *CloakConfig) ComputeCloak(ip net.IP) string {
|
|
if !config.Enabled {
|
|
return ""
|
|
} else if config.NumBits == 0 || config.secret == "" {
|
|
return config.Netname
|
|
}
|
|
|
|
var masked net.IP
|
|
v4ip := ip.To4()
|
|
if v4ip != nil {
|
|
masked = v4ip.Mask(config.ipv4Mask)
|
|
} else {
|
|
masked = ip.Mask(config.ipv6Mask)
|
|
}
|
|
return config.macAndCompose(masked)
|
|
}
|
|
|
|
func (config *CloakConfig) macAndCompose(b []byte) string {
|
|
// SHA3(K || M):
|
|
// https://crypto.stackexchange.com/questions/17735/is-hmac-needed-for-a-sha-3-based-mac
|
|
input := make([]byte, len(config.secret)+len(b))
|
|
copy(input, config.secret[:])
|
|
copy(input[len(config.secret):], b)
|
|
digest := sha3.Sum512(input)
|
|
b32digest := utils.B32Encoder.EncodeToString(digest[:config.numBytes])
|
|
return fmt.Sprintf("%s.%s", b32digest, config.Netname)
|
|
}
|
|
|
|
func (config *CloakConfig) ComputeAccountCloak(accountName string) string {
|
|
// XXX don't bother checking EnabledForAlwaysOn, since if it's disabled,
|
|
// we need to use the server name which we don't have
|
|
if config.NumBits == 0 || config.secret == "" {
|
|
return config.Netname
|
|
}
|
|
|
|
// pad with 16 initial bytes of zeroes, avoiding any possibility of collision
|
|
// with a masked IP that could be an input to ComputeCloak:
|
|
paddedAccountName := make([]byte, 16+len(accountName))
|
|
copy(paddedAccountName[16:], accountName[:])
|
|
return config.macAndCompose(paddedAccountName)
|
|
}
|