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Added hard fail on startup when all defined cipher suites are blackli…
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…sted. Added warning when some ciphers are blacklisted.
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@michelvocks
michelvocks committed Feb 28, 2019
1 parent 3388f6c commit a9d5383
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Showing 3 changed files with 71 additions and 29 deletions.
21 changes: 16 additions & 5 deletions command/server/listener.go
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ import (
_ "crypto/sha512"
"crypto/tls"
"crypto/x509"
"errors"
"fmt"
"io"
"io/ioutil"
Expand Down Expand Up @@ -145,18 +146,28 @@ PASSPHRASECORRECT:
// https://tools.ietf.org/html/rfc7540#appendix-A
//
// Since the CLI (net/http) automatically uses HTTP/2 with TLS 1.2,
// we check here if all specified cipher suites are blacklisted.
// we check here if all or some specified cipher suites are blacklisted.
badCiphersCount := 0

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@ncabatoff

ncabatoff Feb 28, 2019

Collaborator

You can replace badCiphersCount with len(badCiphers) now.
badCiphers := []string{}
for _, cipher := range ciphers {
if isBadCipher(cipher) {
badCiphersCount++

// Get the name of the current cipher.
cipherStr, err := tlsutil.GetCipherName(cipher)
if err != nil {
return nil, nil, nil, errwrap.Wrapf("invalid value for 'tls_cipher_suites': {{err}}", err)
}
badCiphers = append(badCiphers, cipherStr)
}
}
if badCiphersCount == len(ciphers) {
ui.Warn(`WARNING! All cipher suites defined by 'tls_cipher_suites' are blacklisted by the
HTTP/2 specification. HTTP/2 communication with TLS 1.2 will not work as intended
and Vault will be unavailable via the CLI.
Please see https://tools.ietf.org/html/rfc7540#appendix-A for further information.`)
return nil, nil, nil, errors.New("all defined cipher suites by 'tls_cipher_suites' are blacklisted by the HTTP/2 specification")
} else if badCiphersCount > 0 {
ui.Warn(fmt.Sprintf(`WARNING! The following cipher suites defined by 'tls_cipher_suites' are
blacklisted by the HTTP/2 specification:
%v
Please see https://tools.ietf.org/html/rfc7540#appendix-A for further information.`, badCiphers))
}
tlsConf.CipherSuites = ciphers
}
Expand Down
61 changes: 37 additions & 24 deletions helper/tlsutil/tlsutil.go
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Original file line number Diff line number Diff line change
Expand Up @@ -14,34 +14,36 @@ var TLSLookup = map[string]uint16{
"tls12": tls.VersionTLS12,
}

// cipherMap maps the cipher suite names to the internal cipher suite code.
var cipherMap = map[string]uint16{
"TLS_RSA_WITH_RC4_128_SHA": tls.TLS_RSA_WITH_RC4_128_SHA,
"TLS_RSA_WITH_3DES_EDE_CBC_SHA": tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
"TLS_RSA_WITH_AES_128_CBC_SHA": tls.TLS_RSA_WITH_AES_128_CBC_SHA,
"TLS_RSA_WITH_AES_256_CBC_SHA": tls.TLS_RSA_WITH_AES_256_CBC_SHA,
"TLS_RSA_WITH_AES_128_CBC_SHA256": tls.TLS_RSA_WITH_AES_128_CBC_SHA256,
"TLS_RSA_WITH_AES_128_GCM_SHA256": tls.TLS_RSA_WITH_AES_128_GCM_SHA256,
"TLS_RSA_WITH_AES_256_GCM_SHA384": tls.TLS_RSA_WITH_AES_256_GCM_SHA384,
"TLS_ECDHE_ECDSA_WITH_RC4_128_SHA": tls.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA": tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
"TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA": tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
"TLS_ECDHE_RSA_WITH_RC4_128_SHA": tls.TLS_ECDHE_RSA_WITH_RC4_128_SHA,
"TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
"TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256": tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256": tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
"TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256": tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
"TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256": tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
"TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384": tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384": tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
"TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305": tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
"TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305": tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
}

// ParseCiphers parse ciphersuites from the comma-separated string into recognized slice
func ParseCiphers(cipherStr string) ([]uint16, error) {
suites := []uint16{}
ciphers := strutil.ParseStringSlice(cipherStr, ",")
cipherMap := map[string]uint16{
"TLS_RSA_WITH_RC4_128_SHA": tls.TLS_RSA_WITH_RC4_128_SHA,
"TLS_RSA_WITH_3DES_EDE_CBC_SHA": tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
"TLS_RSA_WITH_AES_128_CBC_SHA": tls.TLS_RSA_WITH_AES_128_CBC_SHA,
"TLS_RSA_WITH_AES_256_CBC_SHA": tls.TLS_RSA_WITH_AES_256_CBC_SHA,
"TLS_RSA_WITH_AES_128_CBC_SHA256": tls.TLS_RSA_WITH_AES_128_CBC_SHA256,
"TLS_RSA_WITH_AES_128_GCM_SHA256": tls.TLS_RSA_WITH_AES_128_GCM_SHA256,
"TLS_RSA_WITH_AES_256_GCM_SHA384": tls.TLS_RSA_WITH_AES_256_GCM_SHA384,
"TLS_ECDHE_ECDSA_WITH_RC4_128_SHA": tls.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA": tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
"TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA": tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
"TLS_ECDHE_RSA_WITH_RC4_128_SHA": tls.TLS_ECDHE_RSA_WITH_RC4_128_SHA,
"TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
"TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA": tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256": tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256": tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
"TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256": tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
"TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256": tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
"TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384": tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384": tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
"TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305": tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
"TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305": tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
}
for _, cipher := range ciphers {
if v, ok := cipherMap[cipher]; ok {
suites = append(suites, v)
Expand All @@ -52,3 +54,14 @@ func ParseCiphers(cipherStr string) ([]uint16, error) {

return suites, nil
}

// GetCipherName returns the name of a given cipher suite code or an error if the
// given cipher is unsupported.
func GetCipherName(cipher uint16) (string, error) {
for cipherStr, cipherCode := range cipherMap {
if cipherCode == cipher {
return cipherStr, nil
}
}
return "", fmt.Errorf("unsupported cipher %d", cipher)
}
18 changes: 18 additions & 0 deletions helper/tlsutil/tlsutil_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,3 +28,21 @@ func TestParseCiphers(t *testing.T) {
t.Fatal("cipher order is not preserved")
}
}

func TestGetCipherName(t *testing.T) {
testOkCipherStr := "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA"
testOkCipher := tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
cipherStr, err := GetCipherName(testOkCipher)
if err != nil {
t.Fatal(err)
}
if cipherStr != testOkCipherStr {
t.Fatalf("cipher string should be %s but is %s", testOkCipherStr, cipherStr)
}

var testBadCipher uint16 = 0xC022
cipherStr, err = GetCipherName(testBadCipher)
if err == nil {
t.Fatal("should fail on unsupported cipher 0xC022")
}
}

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