v1.7.0

ADDED:
* cryptparse/ParseTlsCipherStrict()
* cryptparse/ParseTlsCipherSuiteStrict()

cryptparse/errs.go

@@ -8,5 +8,6 @@ var (
 	ErrBadTlsCipher  error = errors.New("invalid TLS cipher suite")
 	ErrBadTlsCurve   error = errors.New("invalid TLS curve")
 	ErrBadTlsVer     error = errors.New("invalid TLS version")
+	ErrUnknownCipher error = errors.New("unknown TLS cipher")
 	ErrUnknownKey    error = errors.New("unknown key type")
 )

cryptparse/funcs.go

@@ -142,6 +142,56 @@ func ParseTlsCipher(s string) (cipherSuite uint16, err error) {
 	return
 }
 
+// ParseTlsCipherStrict is like ParseTlsCipher, but an ErrUnknownCipher error will be raised if no matching cipher is found.
+func ParseTlsCipherStrict(s string) (cipherSuite uint16, err error) {
+
+	var nm string
+	var n uint64
+	var i uint16
+	var ok bool
+
+	if n, err = strconv.ParseUint(s, 10, 16); err != nil {
+		if errors.Is(err, strconv.ErrSyntax) {
+			// It's a name; parse below.
+			err = nil
+		} else {
+			return
+		}
+	} else {
+		// It's a number.
+		if nm = tls.CipherSuiteName(uint16(n)); strings.HasPrefix(nm, "0x") {
+			// ...but invalid.
+			err = ErrBadTlsCipher
+			return
+		} else {
+			// Valid (as number). Return it.
+			cipherSuite = uint16(n)
+			return
+		}
+	}
+
+	s = strings.ToUpper(s)
+	s = strings.ReplaceAll(s, " ", "_")
+
+	// We build a dynamic map of cipher suite names to uint16s (if not already created).
+	if tlsCipherNmToUint == nil {
+		tlsCipherNmToUint = make(map[string]uint16)
+		for i = 0; i <= MaxTlsCipher; i++ {
+			if nm = tls.VersionName(i); !strings.HasPrefix(nm, "0x") {
+				tlsCipherNmToUint[nm] = i
+			}
+		}
+	}
+
+	if i, ok = tlsCipherNmToUint[s]; ok {
+		cipherSuite = i
+	} else {
+		err = ErrUnknownCipher
+	}
+
+	return
+}
+
 /*
 	ParseTlsCiphers parses s as a comma-separated list of cipher suite names/integers and returns a slice of suites.
 
@@ -198,6 +248,31 @@ func ParseTlsCipherSuite(s string) (cipherSuite *tls.CipherSuite, err error) {
 	return
 }
 
+// ParseTlsCipherSuiteStrict is like ParseTlsCipherSuite, but an ErrUnknownCipher error will be raised if no matching cipher is found.
+func ParseTlsCipherSuiteStrict(s string) (cipherSuite *tls.CipherSuite, err error) {
+
+	var cipherId uint16
+
+	if cipherId, err = ParseTlsCipherStrict(s); err != nil {
+		return
+	}
+
+	for _, v := range tls.CipherSuites() {
+		if v.ID == cipherId {
+			cipherSuite = v
+			return
+		}
+	}
+	for _, v := range tls.InsecureCipherSuites() {
+		if v.ID == cipherId {
+			cipherSuite = v
+			return
+		}
+	}
+
+	return
+}
+
 // ParseTlsCipherSuites is like ParseTlsCiphers but returns a []*tls.CipherSuite instead of a []uint16 of TLS cipher identifiers.
 func ParseTlsCipherSuites(s string) (cipherSuites []*tls.CipherSuite, err error) {