Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

[Backport release-1.30] Correctly detect DNS address computation errors #5293

Open
wants to merge 1 commit into
base: release-1.30
Choose a base branch
from
Open

[Backport release-1.30] Correctly detect DNS address computation errors #5293

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 11 additions & 4 deletions pkg/apis/k0s/v1beta1/network.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,8 +18,10 @@ package v1beta1

import (
"encoding/json"
"errors"
"fmt"
"net"
"slices"

"k8s.io/apimachinery/pkg/util/validation/field"
utilnet "k8s.io/utils/net"
Expand Down Expand Up @@ -129,9 +131,14 @@ func (n *Network) DNSAddress() (string, error) {
return "", fmt.Errorf("failed to parse service CIDR %q: %w", n.ServiceCIDR, err)
}

address := ipnet.IP.To4()
if IsIPv6String(ipnet.IP.String()) {
address = ipnet.IP.To16()
address := slices.Clone(ipnet.IP.To4())
if address == nil {
// The network address is not an IPv4 address. This can only happen if
// k0s is running in IPv6-only mode, which is currently not a supported
// configuration. In dual-stack mode, the IPv6 CIDR is stored in
// n.DualStack.IPv6ServiceCIDR. Error out until it is clear how to
// properly calculate the DNS address for a v6 network.
return "", fmt.Errorf("%w: DNS address calculation for non-v4 CIDR: %s", errors.ErrUnsupported, n.ServiceCIDR)
}

prefixlen, _ := ipnet.Mask.Size()
Expand All @@ -142,7 +149,7 @@ func (n *Network) DNSAddress() (string, error) {
}

if !ipnet.Contains(address) {
return "", fmt.Errorf("failed to calculate a valid DNS address: %q", address.String())
return "", fmt.Errorf("failed to calculate DNS address: CIDR too narrow: %s", n.ServiceCIDR)
}

return address.String(), nil
Expand Down
14 changes: 14 additions & 0 deletions pkg/apis/k0s/v1beta1/network_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@ limitations under the License.
package v1beta1

import (
"errors"
"testing"

"github.com/stretchr/testify/suite"
Expand All @@ -40,6 +41,19 @@ func (s *NetworkSuite) TestAddresses() {
s.Require().NoError(err)
s.Equal("10.96.0.250", dns)
})
s.Run("DNS_service_cidr_too_narrow", func() {
n := Network{ServiceCIDR: "192.168.178.0/31"}
dns, err := n.DNSAddress()
s.Zero(dns)
s.ErrorContains(err, "failed to calculate DNS address: CIDR too narrow: 192.168.178.0/31")
})
s.Run("DNS_rejects_v6_service_cidr", func() {
n := Network{ServiceCIDR: "fd00:abcd:1234::/64"}
dns, err := n.DNSAddress()
s.Zero(dns)
s.ErrorIs(err, errors.ErrUnsupported)
s.ErrorContains(err, "unsupported operation: DNS address calculation for non-v4 CIDR: fd00:abcd:1234::/64")
})
s.T().Run("Internal_api_address_default", func(t *testing.T) {
n := DefaultNetwork()
api, err := n.InternalAPIAddresses()
Expand Down
Loading