add kube CSR access

cmd/dkl-local-server/ws-clusters.go

@@ -1,10 +1,18 @@
 package main
 
 import (
+	"errors"
+	"fmt"
 	"log"
 	"net/url"
+	"regexp"
 	"strconv"
+	"strings"
+	"time"
 
+	"github.com/cloudflare/cfssl/config"
+	"github.com/cloudflare/cfssl/csr"
+	"github.com/cloudflare/cfssl/signer"
 	restful "github.com/emicklei/go-restful"
 
 	"novit.tech/direktil/local-server/pkg/mime"
@@ -151,7 +159,25 @@ func wsClusterSSHUserCASign(req *restful.Request, resp *restful.Response) {
 		return
 	}
 
-	cert, err := sshCASign(clusterName, []byte(signReq.PubKey), signReq.Principal, signReq.Validity, signReq.Options...)
+	now := time.Now().Truncate(time.Second)
+	notBefore, notAfter, err := parseCertDurationRange(signReq.Validity, now)
+	if err != nil {
+		wsError(resp, fmt.Errorf("invalid validity: %w", err))
+		return
+	}
+
+	const sshTimestamp = "20060102150405Z"
+
+	validity := notBefore.Format(sshTimestamp) + ":"
+	if notAfter.IsZero() {
+		validity += "forever"
+	} else {
+		validity += notAfter.Format(sshTimestamp)
+	}
+
+	log.Printf("sign ssh public key, validity %s -> %s", signReq.Validity, validity)
+
+	cert, err := sshCASign(clusterName, []byte(signReq.PubKey), signReq.Principal, validity, signReq.Options...)
 	if err != nil {
 		wsError(resp, err)
 		return
@@ -159,3 +185,147 @@ func wsClusterSSHUserCASign(req *restful.Request, resp *restful.Response) {
 
 	resp.Write(cert)
 }
+
+type KubeSignReq struct {
+	CSR      string
+	User     string
+	Group    string
+	Validity string
+}
+
+func wsClusterKubeCASign(req *restful.Request, resp *restful.Response) {
+	clusterName := req.PathParameter("cluster-name")
+
+	signReq := KubeSignReq{}
+	err := req.ReadEntity(&signReq)
+	if err != nil {
+		wsError(resp, err)
+		return
+	}
+
+	now := time.Now().Truncate(time.Second)
+	notBefore, notAfter, err := parseCertDurationRange(signReq.Validity, now)
+	if err != nil {
+		wsError(resp, fmt.Errorf("invalid validity: %w", err))
+		return
+	}
+
+	var names []csr.Name
+	if signReq.Group != "" {
+		names = []csr.Name{{O: signReq.Group}}
+	}
+
+	ca, err := getUsableClusterCA(clusterName, "cluster")
+	if err != nil {
+		wsError(resp, fmt.Errorf("get cluster CA failed: %w", err))
+		return
+	}
+
+	caSigner, err := ca.Signer(&config.Signing{
+		Default: &config.SigningProfile{
+			Usage:  []string{"client auth"},
+			Expiry: notAfter.Sub(now),
+		},
+	})
+	if err != nil {
+		wsError(resp, err)
+		return
+	}
+
+	csr := signer.SignRequest{
+		Request: signReq.CSR,
+		Subject: &signer.Subject{
+			CN:    signReq.User,
+			Names: names,
+		},
+		NotBefore: notBefore,
+		NotAfter:  notAfter,
+	}
+
+	cert, err := caSigner.Sign(csr)
+	if err != nil {
+		wsError(resp, err)
+		return
+	}
+
+	resp.Write(cert)
+}
+
+func parseCertDurationRange(d string, now time.Time) (notBefore, notAfter time.Time, err error) {
+	if d == "" {
+		return
+	}
+
+	d1, d2, ok := strings.Cut(d, ":")
+
+	if ok {
+		notBefore, err = parseCertDuration(d1, now)
+		if err != nil {
+			return
+		}
+		notAfter, err = parseCertDuration(d2, now)
+	} else {
+		notAfter, err = parseCertDuration(d, now)
+	}
+
+	if err != nil {
+		return
+	}
+
+	if notBefore.IsZero() {
+		notBefore = now.Add(-5 * time.Minute)
+	}
+
+	return
+}
+
+var durRegex = regexp.MustCompile("^([+-]?)([0-9]+)([yMdwhms])")
+
+func parseCertDuration(d string, now time.Time) (t time.Time, err error) {
+	if d == "" {
+		return
+	}
+
+	direction := 1
+	t = now
+
+	for d != "" {
+		match := durRegex.FindStringSubmatch(d)
+		if match == nil {
+			t = time.Time{}
+			err = errors.New("invalid duration: " + strconv.Quote(d))
+			return
+		}
+
+		d = d[len(match[0]):]
+
+		switch match[1] {
+		case "+":
+			direction = 1
+		case "-":
+			direction = -1
+		}
+
+		qty, _ := strconv.Atoi(match[2])
+		unit := match[3]
+
+		switch unit {
+		case "y":
+			t = t.AddDate(qty*direction, 0, 0)
+		case "M":
+			t = t.AddDate(0, qty*direction, 0)
+		case "d":
+			t = t.AddDate(0, 0, qty*direction)
+		case "w":
+			t = t.AddDate(0, 0, 7*qty*direction)
+		case "h":
+			t = t.Add(time.Duration(qty*direction) * time.Hour)
+		case "m":
+			t = t.Add(time.Duration(qty*direction) * time.Minute)
+		case "s":
+			t = t.Add(time.Duration(qty*direction) * time.Second)
+		}
+	}
+
+	return
+}