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Support min/max TLS version in TLS config (#3567)
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* Add minimum tls version support in tls config

Signed-off-by: Ashmita152 <[email protected]>

* Feedbacks

Signed-off-by: Ashmita152 <[email protected]>

* Add maximum tls version support in tls config

Signed-off-by: Ashmita152 <[email protected]>

* Feedbacks

Signed-off-by: Ashmita152 <[email protected]>
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Ashmita152 authored Mar 7, 2022
1 parent df44af3 commit 46bced6
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Showing 6 changed files with 109 additions and 4 deletions.
16 changes: 16 additions & 0 deletions pkg/config/tlscfg/ciphersuites.go
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,14 @@ import (
"fmt"
)

// https://pkg.go.dev/crypto/tls#pkg-constants
var versions = map[string]uint16{
"1.0": tls.VersionTLS10,
"1.1": tls.VersionTLS11,
"1.2": tls.VersionTLS12,
"1.3": tls.VersionTLS13,
}

func allCiphers() map[string]uint16 {
acceptedCiphers := make(map[string]uint16)
for _, suite := range tls.CipherSuites() {
Expand All @@ -40,3 +48,11 @@ func CipherSuiteNamesToIDs(cipherNames []string) ([]uint16, error) {
}
return ciphersIDs, nil
}

// VersionNameToID returns the version ID from version name
func VersionNameToID(versionName string) (uint16, error) {
if version, ok := versions[versionName]; ok {
return version, nil
}
return 0, fmt.Errorf("unknown tls version %q", versionName)
}
33 changes: 32 additions & 1 deletion pkg/config/tlscfg/ciphersuites_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ import (
"testing"
)

func TestTLSCipherSuites(t *testing.T) {
func TestCipherSuiteNamesToIDs(t *testing.T) {
tests := []struct {
flag []string
expected []uint16
Expand Down Expand Up @@ -68,3 +68,34 @@ func TestTLSCipherSuites(t *testing.T) {
}
}
}

func TestVersionNameToID(t *testing.T) {
tests := []struct {
flag string
expected uint16
expectedError bool
}{
{
// Happy case
flag: "1.1",
expected: tls.VersionTLS11,
expectedError: false,
},
{
// Invalid flag
flag: "Invalid",
expected: 0,
expectedError: true,
},
}

for i, test := range tests {
uIntFlag, err := VersionNameToID(test.flag)
if !reflect.DeepEqual(uIntFlag, test.expected) {
t.Errorf("%d: expected %+v, got %+v", i, test.expected, uIntFlag)
}
if test.expectedError && err == nil {
t.Errorf("%d: expecting error, got %+v", i, err)
}
}
}
6 changes: 6 additions & 0 deletions pkg/config/tlscfg/flags.go
Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,8 @@ const (
tlsClientCA = tlsPrefix + ".client-ca"
tlsSkipHostVerify = tlsPrefix + ".skip-host-verify"
tlsCipherSuites = tlsPrefix + ".cipher-suites"
tlsMinVersion = tlsPrefix + ".min-version"
tlsMaxVersion = tlsPrefix + ".max-version"
)

// ClientFlagsConfig describes which CLI flags for TLS client should be generated.
Expand Down Expand Up @@ -60,6 +62,8 @@ func (c ServerFlagsConfig) AddFlags(flags *flag.FlagSet) {
flags.String(c.Prefix+tlsKey, "", "Path to a TLS Private Key file, used to identify this server to clients")
flags.String(c.Prefix+tlsClientCA, "", "Path to a TLS CA (Certification Authority) file used to verify certificates presented by clients (if unset, all clients are permitted)")
flags.String(c.Prefix+tlsCipherSuites, "", "Comma-separated list of cipher suites for the server, values are from tls package constants (https://golang.org/pkg/crypto/tls/#pkg-constants).")
flags.String(c.Prefix+tlsMinVersion, "", "Minimum TLS version supported (Possible values: 1.0, 1.1, 1.2, 1.3)")
flags.String(c.Prefix+tlsMaxVersion, "", "Maximum TLS version supported (Possible values: 1.0, 1.1, 1.2, 1.3)")
}

// InitFromViper creates tls.Config populated with values retrieved from Viper.
Expand All @@ -82,6 +86,8 @@ func (c ServerFlagsConfig) InitFromViper(v *viper.Viper) Options {
p.KeyPath = v.GetString(c.Prefix + tlsKey)
p.ClientCAPath = v.GetString(c.Prefix + tlsClientCA)
p.CipherSuites = strings.Split(stripWhiteSpace(v.GetString(c.Prefix+tlsCipherSuites)), ",")
p.MinVersion = v.GetString(c.Prefix + tlsMinVersion)
p.MaxVersion = v.GetString(c.Prefix + tlsMaxVersion)
return p
}

Expand Down
4 changes: 4 additions & 0 deletions pkg/config/tlscfg/flags_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -75,6 +75,8 @@ func TestServerFlags(t *testing.T) {
"--prefix.tls.cert=cert-file",
"--prefix.tls.key=key-file",
"--prefix.tls.cipher-suites=TLS_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA",
"--prefix.tls.min-version=1.2",
"--prefix.tls.max-version=1.3",
}

tests := []struct {
Expand Down Expand Up @@ -109,6 +111,8 @@ func TestServerFlags(t *testing.T) {
KeyPath: "key-file",
ClientCAPath: test.file,
CipherSuites: []string{"TLS_AES_256_GCM_SHA384", "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA"},
MinVersion: "1.2",
MaxVersion: "1.3",
}, tlsOpts)
})
}
Expand Down
26 changes: 26 additions & 0 deletions pkg/config/tlscfg/options.go
Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,8 @@ type Options struct {
ServerName string `mapstructure:"server_name"` // only for client-side TLS config
ClientCAPath string `mapstructure:"client_ca"` // only for server-side TLS config for client auth
CipherSuites []string `mapstructure:"cipher_suites"`
MinVersion string `mapstructure:"min_version"`
MaxVersion string `mapstructure:"max_version"`
SkipHostVerify bool `mapstructure:"skip_host_verify"`
certWatcher *certWatcher `mapstructure:"-"`
}
Expand All @@ -42,6 +44,8 @@ var systemCertPool = x509.SystemCertPool // to allow overriding in unit test

// Config loads TLS certificates and returns a TLS Config.
func (p *Options) Config(logger *zap.Logger) (*tls.Config, error) {
var minVersionId, maxVersionId uint16

certPool, err := p.loadCertPool()
if err != nil {
return nil, fmt.Errorf("failed to load CA CertPool: %w", err)
Expand All @@ -52,12 +56,34 @@ func (p *Options) Config(logger *zap.Logger) (*tls.Config, error) {
return nil, fmt.Errorf("failed to get cipher suite ids from cipher suite names: %w", err)
}

if p.MinVersion != "" {
minVersionId, err = VersionNameToID(p.MinVersion)
if err != nil {
return nil, fmt.Errorf("failed to get minimum tls version: %w", err)
}
}

if p.MaxVersion != "" {
maxVersionId, err = VersionNameToID(p.MaxVersion)
if err != nil {
return nil, fmt.Errorf("failed to get maximum tls version: %w", err)
}
}

if p.MinVersion != "" && p.MaxVersion != "" {
if minVersionId > maxVersionId {
return nil, fmt.Errorf("minimum tls version can't be greater than maximum tls version")
}
}

// #nosec G402
tlsCfg := &tls.Config{
RootCAs: certPool,
ServerName: p.ServerName,
InsecureSkipVerify: p.SkipHostVerify,
CipherSuites: cipherSuiteIds,
MinVersion: minVersionId,
MaxVersion: maxVersionId,
}

if p.ClientCAPath != "" {
Expand Down
28 changes: 25 additions & 3 deletions pkg/config/tlscfg/options_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -109,25 +109,47 @@ func TestOptionsToConfig(t *testing.T) {
expectError: "failed to load CA",
},
{
name: "should fail with invalid Client CA pool",
name: "should fail with invalid TLS Client CA pool",
options: Options{
ClientCAPath: testCertKeyLocation + "/bad-CA-cert.txt",
},
expectError: "failed to parse CA",
},
{
name: "should pass with valid Client CA pool",
name: "should pass with valid TLS Client CA pool",
options: Options{
ClientCAPath: testCertKeyLocation + "/example-CA-cert.pem",
},
},
{
name: "should fail with invalid Cipher Suite",
name: "should fail with invalid TLS Cipher Suite",
options: Options{
CipherSuites: []string{"TLS_INVALID_CIPHER_SUITE"},
},
expectError: "failed to get cipher suite ids from cipher suite names: cipher suite TLS_INVALID_CIPHER_SUITE not supported or doesn't exist",
},
{
name: "should fail with invalid TLS Min Version",
options: Options{
MinVersion: "Invalid",
},
expectError: "failed to get minimum tls version",
},
{
name: "should fail with invalid TLS Max Version",
options: Options{
MaxVersion: "Invalid",
},
expectError: "failed to get maximum tls version",
},
{
name: "should fail with TLS Min Version greater than TLS Max Version error",
options: Options{
MinVersion: "1.2",
MaxVersion: "1.1",
},
expectError: "minimum tls version can't be greater than maximum tls version",
},
}

for _, test := range tests {
Expand Down

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