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Root constraint usage and support in nebula-cert

This commit is contained in:
Nate Brown 2019-12-17 17:59:21 -08:00
parent 0dc9aafa14
commit 328db6bb82
5 changed files with 71 additions and 11 deletions
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27
cert/cert.go
View File

@ -267,11 +267,30 @@ func (nc *NebulaCertificate) Verify(t time.Time, ncp *NebulaCAPool) (bool, error
return false, fmt.Errorf("certificate signature did not match")
}
if err := nc.CheckRootConstrains(signer); err != nil {
return false, err
}
return true, nil
}
// CheckRootConstrains returns an error if the certificate violates constraints set on the root (groups, ips, subnets)
func (nc *NebulaCertificate) CheckRootConstrains(signer *NebulaCertificate) error {
// Make sure this cert wasn't valid before the root
if signer.Details.NotAfter.Before(nc.Details.NotAfter) {
return fmt.Errorf("certificate expires after signing certificate")
}
// Make sure this cert isn't valid after the root
if signer.Details.NotBefore.After(nc.Details.NotBefore) {
return fmt.Errorf("certificate is valid before the signing certificate")
}
// If the signer has a limited set of groups make sure the cert only contains a subset
if len(signer.Details.InvertedGroups) > 0 {
for _, g := range nc.Details.Groups {
if _, ok := signer.Details.InvertedGroups[g]; !ok {
return false, fmt.Errorf("certificate contained a group not present on the signing ca: %s", g)
return fmt.Errorf("certificate contained a group not present on the signing ca: %s", g)
}
}
}
@ -280,7 +299,7 @@ func (nc *NebulaCertificate) Verify(t time.Time, ncp *NebulaCAPool) (bool, error
if len(signer.Details.Ips) > 0 {
for _, ip := range nc.Details.Ips {
if !netMatch(ip, signer.Details.Ips) {
return false, fmt.Errorf("certificate contained an ip assignment outside the limitations of the signing ca: %s", ip.String())
return fmt.Errorf("certificate contained an ip assignment outside the limitations of the signing ca: %s", ip.String())
}
}
}
@ -289,12 +308,12 @@ func (nc *NebulaCertificate) Verify(t time.Time, ncp *NebulaCAPool) (bool, error
if len(signer.Details.Subnets) > 0 {
for _, subnet := range nc.Details.Subnets {
if !netMatch(subnet, signer.Details.Subnets) {
return false, fmt.Errorf("certificate contained a subnet assignment outside the limitations of the signing ca: %s", subnet)
return fmt.Errorf("certificate contained a subnet assignment outside the limitations of the signing ca: %s", subnet)
}
}
}
return true, nil
return nil
}
// VerifyPrivateKey checks that the public key in the Nebula certificate and a supplied private key match

39
cmd/nebula-cert/ca.go
View File

@ -6,6 +6,7 @@ import (
"fmt"
"io"
"io/ioutil"
"net"
"os"
"strings"
"time"
@ -21,6 +22,8 @@ type caFlags struct {
outKeyPath *string
outCertPath *string
groups *string
ips *string
subnets *string
}
func newCaFlags() *caFlags {
@ -31,6 +34,8 @@ func newCaFlags() *caFlags {
cf.outKeyPath = cf.set.String("out-key", "ca.key", "Optional: path to write the private key to")
cf.outCertPath = cf.set.String("out-crt", "ca.crt", "Optional: path to write the certificate to")
cf.groups = cf.set.String("groups", "", "Optional: comma separated list of groups. This will limit which groups subordinate certs can use")
cf.ips = cf.set.String("ips", "", "Optional: comma separated list of ip and network in CIDR notation. This will limit which ip addresses and networks subordinate certs can use")
cf.subnets = cf.set.String("subnets", "", "Optional: comma separated list of ip and network in CIDR notation. This will limit which subnet addresses and networks subordinate certs can use")
return &cf
}
@ -55,7 +60,7 @@ func ca(args []string, out io.Writer, errOut io.Writer) error {
return &helpError{"-duration must be greater than 0"}
}
groups := []string{}
var groups []string
if *cf.groups != "" {
for _, rg := range strings.Split(*cf.groups, ",") {
g := strings.TrimSpace(rg)
@ -65,6 +70,36 @@ func ca(args []string, out io.Writer, errOut io.Writer) error {
}
}
var ips []*net.IPNet
if *cf.ips != "" {
for _, rs := range strings.Split(*cf.ips, ",") {
rs := strings.Trim(rs, " ")
if rs != "" {
ip, ipNet, err := net.ParseCIDR(rs)
if err != nil {
return newHelpErrorf("invalid ip definition: %s", err)
}
ipNet.IP = ip
ips = append(ips, ipNet)
}
}
}
var subnets []*net.IPNet
if *cf.subnets != "" {
for _, rs := range strings.Split(*cf.subnets, ",") {
rs := strings.Trim(rs, " ")
if rs != "" {
_, s, err := net.ParseCIDR(rs)
if err != nil {
return newHelpErrorf("invalid subnet definition: %s", err)
}
subnets = append(subnets, s)
}
}
}
pub, rawPriv, err := ed25519.GenerateKey(rand.Reader)
if err != nil {
return fmt.Errorf("error while generating ed25519 keys: %s", err)
@ -74,6 +109,8 @@ func ca(args []string, out io.Writer, errOut io.Writer) error {
Details: cert.NebulaCertificateDetails{
Name: *cf.name,
Groups: groups,
Ips: ips,
Subnets: subnets,
NotBefore: time.Now(),
NotAfter: time.Now().Add(*cf.duration),
PublicKey: pub,

6
cmd/nebula-cert/ca_test.go
View File

@ -29,12 +29,16 @@ func Test_caHelp(t *testing.T) {
" \tOptional: amount of time the certificate should be valid for. Valid time units are seconds: \"s\", minutes: \"m\", hours: \"h\" (default 8760h0m0s)\n"+
" -groups string\n"+
" \tOptional: comma separated list of groups. This will limit which groups subordinate certs can use\n"+
" -ips string\n"+
" \tOptional: comma separated list of ip and network in CIDR notation. This will limit which ip addresses and networks subordinate certs can use\n"+
" -name string\n"+
" \tRequired: name of the certificate authority\n"+
" -out-crt string\n"+
" \tOptional: path to write the certificate to (default \"ca.crt\")\n"+
" -out-key string\n"+
" \tOptional: path to write the private key to (default \"ca.key\")\n",
" \tOptional: path to write the private key to (default \"ca.key\")\n"+
" -subnets string\n"+
" \tOptional: comma separated list of ip and network in CIDR notation. This will limit which subnet addresses and networks subordinate certs can use\n",
ob.String(),
)
}

8
cmd/nebula-cert/sign.go
View File

@ -103,10 +103,6 @@ func signCert(args []string, out io.Writer, errOut io.Writer) error {
*sf.duration = time.Until(caCert.Details.NotAfter) - time.Second*1
}
if caCert.Details.NotAfter.Before(time.Now().Add(*sf.duration)) {
return fmt.Errorf("refusing to generate certificate with duration beyond root expiration: %s", caCert.Details.NotAfter)
}
ip, ipNet, err := net.ParseCIDR(*sf.ip)
if err != nil {
return newHelpErrorf("invalid ip definition: %s", err)
@ -165,6 +161,10 @@ func signCert(args []string, out io.Writer, errOut io.Writer) error {
},
}
if err := nc.CheckRootConstrains(caCert); err != nil {
return fmt.Errorf("refusing to sign, root certificate constraints violated: %s", err)
}
if *sf.outKeyPath == "" {
*sf.outKeyPath = *sf.name + ".key"
}

2
cmd/nebula-cert/sign_test.go
View File

@ -253,7 +253,7 @@ func Test_signCert(t *testing.T) {
ob.Reset()
eb.Reset()
args = []string{"-ca-crt", caCrtF.Name(), "-ca-key", caKeyF.Name(), "-name", "test", "-ip", "1.1.1.1/24", "-out-crt", crtF.Name(), "-out-key", keyF.Name(), "-duration", "1000m", "-subnets", "10.1.1.1/32, , 10.2.2.2/32 , , ,, 10.5.5.5/32", "-groups", "1,, 2 , ,,,3,4,5"}
assert.EqualError(t, signCert(args, ob, eb), "refusing to generate certificate with duration beyond root expiration: "+ca.Details.NotAfter.Format("2006-01-02 15:04:05 +0000 UTC"))
assert.EqualError(t, signCert(args, ob, eb), "refusing to sign, root certificate constraints violated: certificate expires after signing certificate")
assert.Empty(t, ob.String())
assert.Empty(t, eb.String())