AdGuardHome/internal/aghtls/aghtls.go

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// Package aghtls contains utilities for work with TLS.
package aghtls
import (
"crypto/tls"
"crypto/x509"
"fmt"
"net/netip"
"github.com/AdguardTeam/golibs/log"
)
// init makes sure that the cipher name map is filled.
//
// TODO(a.garipov): Propose a similar API to crypto/tls.
func init() {
suites := tls.CipherSuites()
cipherSuites = make(map[string]uint16, len(suites))
for _, s := range suites {
cipherSuites[s.Name] = s.ID
}
log.Debug("tls: known ciphers: %q", cipherSuites)
}
// cipherSuites are a name-to-ID mapping of cipher suites from crypto/tls. It
// is filled by init. It must not be modified.
var cipherSuites map[string]uint16
// ParseCiphers parses a slice of cipher suites from cipher names.
func ParseCiphers(cipherNames []string) (cipherIDs []uint16, err error) {
if cipherNames == nil {
return nil, nil
}
cipherIDs = make([]uint16, 0, len(cipherNames))
for _, name := range cipherNames {
id, ok := cipherSuites[name]
if !ok {
return nil, fmt.Errorf("unknown cipher %q", name)
}
cipherIDs = append(cipherIDs, id)
}
return cipherIDs, nil
}
// SaferCipherSuites returns a set of default cipher suites with vulnerable and
// weak cipher suites removed.
func SaferCipherSuites() (safe []uint16) {
for _, s := range tls.CipherSuites() {
switch s.ID {
case
tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
tls.TLS_RSA_WITH_AES_128_CBC_SHA,
tls.TLS_RSA_WITH_AES_256_CBC_SHA,
tls.TLS_RSA_WITH_AES_128_CBC_SHA256,
tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256:
// Less safe 3DES and CBC suites, go on.
default:
safe = append(safe, s.ID)
}
}
return safe
}
// CertificateHasIP returns true if cert has at least a single IP address among
// its subjectAltNames.
func CertificateHasIP(cert *x509.Certificate) (ok bool) {
if len(cert.IPAddresses) > 0 {
return true
}
for _, name := range cert.DNSNames {
if _, err := netip.ParseAddr(name); err == nil {
return true
}
}
return false
}