feat: dnssec load keys from AWS Secrets Manager

Signed-off-by: kcolemangt <20099734+kcolemangt@users.noreply.github.com>

go.mod

@@ -9,6 +9,8 @@ require (
 	github.com/antonmedv/expr v1.15.5
 	github.com/apparentlymart/go-cidr v1.1.0
 	github.com/aws/aws-sdk-go v1.51.16
+	github.com/aws/aws-sdk-go-v2/config v1.27.11
+	github.com/aws/aws-sdk-go-v2/service/secretsmanager v1.28.6
 	github.com/coredns/caddy v1.1.1
 	github.com/dnstap/golang-dnstap v0.4.0
 	github.com/farsightsec/golang-framestream v0.3.0
@@ -58,6 +60,18 @@ require (
 	github.com/DataDog/go-tuf v1.0.2-0.5.2 // indirect
 	github.com/DataDog/sketches-go v1.4.2 // indirect
 	github.com/Microsoft/go-winio v0.6.1 // indirect
+	github.com/aws/aws-sdk-go-v2 v1.26.1 // indirect
+	github.com/aws/aws-sdk-go-v2/credentials v1.17.11 // indirect
+	github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.16.1 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/configsources v1.3.5 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.6.5 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/ini v1.8.0 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.11.2 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.11.7 // indirect
+	github.com/aws/aws-sdk-go-v2/service/sso v1.20.5 // indirect
+	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.23.4 // indirect
+	github.com/aws/aws-sdk-go-v2/service/sts v1.28.6 // indirect
+	github.com/aws/smithy-go v1.20.2 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/coreos/go-semver v0.3.0 // indirect

go.sum

@@ -54,6 +54,34 @@ github.com/apparentlymart/go-cidr v1.1.0 h1:2mAhrMoF+nhXqxTzSZMUzDHkLjmIHC+Zzn4t
 github.com/apparentlymart/go-cidr v1.1.0/go.mod h1:EBcsNrHc3zQeuaeCeCtQruQm+n9/YjEn/vI25Lg7Gwc=
 github.com/aws/aws-sdk-go v1.51.16 h1:vnWKK8KjbftEkuPX8bRj3WHsLy1uhotn0eXptpvrxJI=
 github.com/aws/aws-sdk-go v1.51.16/go.mod h1:LF8svs817+Nz+DmiMQKTO3ubZ/6IaTpq3TjupRn3Eqk=
+github.com/aws/aws-sdk-go-v2 v1.26.1 h1:5554eUqIYVWpU0YmeeYZ0wU64H2VLBs8TlhRB2L+EkA=
+github.com/aws/aws-sdk-go-v2 v1.26.1/go.mod h1:ffIFB97e2yNsv4aTSGkqtHnppsIJzw7G7BReUZ3jCXM=
+github.com/aws/aws-sdk-go-v2/config v1.27.11 h1:f47rANd2LQEYHda2ddSCKYId18/8BhSRM4BULGmfgNA=
+github.com/aws/aws-sdk-go-v2/config v1.27.11/go.mod h1:SMsV78RIOYdve1vf36z8LmnszlRWkwMQtomCAI0/mIE=
+github.com/aws/aws-sdk-go-v2/credentials v1.17.11 h1:YuIB1dJNf1Re822rriUOTxopaHHvIq0l/pX3fwO+Tzs=
+github.com/aws/aws-sdk-go-v2/credentials v1.17.11/go.mod h1:AQtFPsDH9bI2O+71anW6EKL+NcD7LG3dpKGMV4SShgo=
+github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.16.1 h1:FVJ0r5XTHSmIHJV6KuDmdYhEpvlHpiSd38RQWhut5J4=
+github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.16.1/go.mod h1:zusuAeqezXzAB24LGuzuekqMAEgWkVYukBec3kr3jUg=
+github.com/aws/aws-sdk-go-v2/internal/configsources v1.3.5 h1:aw39xVGeRWlWx9EzGVnhOR4yOjQDHPQ6o6NmBlscyQg=
+github.com/aws/aws-sdk-go-v2/internal/configsources v1.3.5/go.mod h1:FSaRudD0dXiMPK2UjknVwwTYyZMRsHv3TtkabsZih5I=
+github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.6.5 h1:PG1F3OD1szkuQPzDw3CIQsRIrtTlUC3lP84taWzHlq0=
+github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.6.5/go.mod h1:jU1li6RFryMz+so64PpKtudI+QzbKoIEivqdf6LNpOc=
+github.com/aws/aws-sdk-go-v2/internal/ini v1.8.0 h1:hT8rVHwugYE2lEfdFE0QWVo81lF7jMrYJVDWI+f+VxU=
+github.com/aws/aws-sdk-go-v2/internal/ini v1.8.0/go.mod h1:8tu/lYfQfFe6IGnaOdrpVgEL2IrrDOf6/m9RQum4NkY=
+github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.11.2 h1:Ji0DY1xUsUr3I8cHps0G+XM3WWU16lP6yG8qu1GAZAs=
+github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.11.2/go.mod h1:5CsjAbs3NlGQyZNFACh+zztPDI7fU6eW9QsxjfnuBKg=
+github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.11.7 h1:ogRAwT1/gxJBcSWDMZlgyFUM962F51A5CRhDLbxLdmo=
+github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.11.7/go.mod h1:YCsIZhXfRPLFFCl5xxY+1T9RKzOKjCut+28JSX2DnAk=
+github.com/aws/aws-sdk-go-v2/service/secretsmanager v1.28.6 h1:TIOEjw0i2yyhmhRry3Oeu9YtiiHWISZ6j/irS1W3gX4=
+github.com/aws/aws-sdk-go-v2/service/secretsmanager v1.28.6/go.mod h1:3Ba++UwWd154xtP4FRX5pUK3Gt4up5sDHCve6kVfE+g=
+github.com/aws/aws-sdk-go-v2/service/sso v1.20.5 h1:vN8hEbpRnL7+Hopy9dzmRle1xmDc7o8tmY0klsr175w=
+github.com/aws/aws-sdk-go-v2/service/sso v1.20.5/go.mod h1:qGzynb/msuZIE8I75DVRCUXw3o3ZyBmUvMwQ2t/BrGM=
+github.com/aws/aws-sdk-go-v2/service/ssooidc v1.23.4 h1:Jux+gDDyi1Lruk+KHF91tK2KCuY61kzoCpvtvJJBtOE=
+github.com/aws/aws-sdk-go-v2/service/ssooidc v1.23.4/go.mod h1:mUYPBhaF2lGiukDEjJX2BLRRKTmoUSitGDUgM4tRxak=
+github.com/aws/aws-sdk-go-v2/service/sts v1.28.6 h1:cwIxeBttqPN3qkaAjcEcsh8NYr8n2HZPkcKgPAi1phU=
+github.com/aws/aws-sdk-go-v2/service/sts v1.28.6/go.mod h1:FZf1/nKNEkHdGGJP/cI2MoIMquumuRK6ol3QQJNDxmw=
+github.com/aws/smithy-go v1.20.2 h1:tbp628ireGtzcHDDmLT/6ADHidqnwgF57XOXZe6tp4Q=
+github.com/aws/smithy-go v1.20.2/go.mod h1:krry+ya/rV9RDcV/Q16kpu6ypI4K2czasz0NC3qS14E=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=

plugin/dnssec/README.md

@@ -16,7 +16,7 @@ This plugin can only be used once per Server Block.
 
 ~~~
 dnssec [ZONES... ] {
-    key file KEY...
+    key file|secret KEY...
     cache_capacity CAPACITY
 }
 ~~~
@@ -49,6 +49,22 @@ used.
     * generated public key `Kexample.org+013+45330.key`
     * generated private key `Kexample.org+013+45330.private`
 
+* `key secret` indicates that **KEY** secret(s) should be read from AWS Secrets Manager. Secret names or
+  ARNs may be used. After generating the keys as described in the `key file` section, you can store them
+  in AWS Secrets Manager using the following AWS CLI v2 command:
+
+  ```sh
+  aws secretsmanager create-secret --name "Kexample.org.+013+45330" \
+  --description "DNSSEC keys for example.org" \
+  --secret-string "$(jq -n --arg key "$(cat Kexample.org.+013+45330.key)" \
+  --arg private "$(cat Kexample.org.+013+45330.private)" \
+  '{key: $key, private: $private}')"
+  ```
+
+  This command reads the contents of the `.key` and `.private` files, constructs a JSON object, and stores it
+  as a new secret in AWS Secrets Manager with the specified name and description. CoreDNS will then fetch
+  the key data from AWS Secrets Manager when using the `key secret` directive.
+
 * `cache_capacity` indicates the capacity of the cache. The dnssec plugin uses a cache to store
   RRSIGs. The default for **CAPACITY** is 10000.
 
@@ -75,6 +91,17 @@ example.org {
 }
 ~~~
 
+Sign responses for `example.org` with the key stored in AWS Secrets Manager under the secret name "Kexample.org.+013+45330".
+
+~~~ corefile
+example.org {
+    dnssec {
+        key secret Kexample.org.+013+45330
+    }
+    whoami
+}
+~~~
+
 Sign responses for a kubernetes zone with the key "Kcluster.local+013+45129.key".
 
 ~~~

plugin/dnssec/dnskey.go

@@ -1,16 +1,21 @@
 package dnssec
 
 import (
+	"context"
 	"crypto"
 	"crypto/ecdsa"
 	"crypto/rsa"
+	"encoding/json"
 	"errors"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/coredns/coredns/request"
 
+	"github.com/aws/aws-sdk-go-v2/config"
+	"github.com/aws/aws-sdk-go-v2/service/secretsmanager"
 	"github.com/miekg/dns"
 	"golang.org/x/crypto/ed25519"
 )
@@ -23,6 +28,12 @@ type DNSKEY struct {
 	tag uint16
 }
 
+// SecretKeyData represents the structure of the DNS keys stored in AWS Secrets Manager.
+type SecretKeyData struct {
+	Key     string `json:"key"`
+	Private string `json:"private"`
+}
+
 // ParseKeyFile read a DNSSEC keyfile as generated by dnssec-keygen or other
 // utilities. It adds ".key" for the public key and ".private" for the private key.
 func ParseKeyFile(pubFile, privFile string) (*DNSKEY, error) {
@@ -63,6 +74,69 @@ func ParseKeyFile(pubFile, privFile string) (*DNSKEY, error) {
 	return &DNSKEY{K: dk, D: dk.ToDS(dns.SHA256), s: nil, tag: 0}, errors.New("no private key found")
 }
 
+// ParseKeySecret retrieves and parses a DNSSEC key pair from AWS Secrets Manager.
+func ParseKeySecret(secretID string) (*DNSKEY, error) {
+	// Load the AWS SDK configuration
+	cfg, err := config.LoadDefaultConfig(context.TODO())
+	if err != nil {
+		return nil, err
+	}
+
+	// Create a Secrets Manager client
+	client := secretsmanager.NewFromConfig(cfg)
+
+	// Retrieve the secret value
+	input := &secretsmanager.GetSecretValueInput{
+		SecretId: &secretID,
+	}
+	result, err := client.GetSecretValue(context.TODO(), input)
+	if err != nil {
+		return nil, err
+	}
+
+	// Parse the secret string into SecretKeyData
+	var secretData SecretKeyData
+	err = json.Unmarshal([]byte(*result.SecretString), &secretData)
+	if err != nil {
+		return nil, err
+	}
+
+	// Parse the public key
+	rr, err := dns.NewRR(secretData.Key)
+	if err != nil {
+		return nil, err
+	}
+	dk, ok := rr.(*dns.DNSKEY)
+	if !ok {
+		return nil, errors.New("invalid public key format")
+	}
+
+	// Parse the private key
+	p, err := dk.ReadPrivateKey(strings.NewReader(secretData.Private), secretID)
+	if err != nil {
+		return nil, err
+	}
+
+	// Create the DNSKEY structure
+	var s crypto.Signer
+	var tag uint16
+	switch key := p.(type) {
+	case *rsa.PrivateKey:
+		s = key
+		tag = dk.KeyTag()
+	case *ecdsa.PrivateKey:
+		s = key
+		tag = dk.KeyTag()
+	case ed25519.PrivateKey:
+		s = key
+		tag = dk.KeyTag()
+	default:
+		return nil, errors.New("unsupported key type")
+	}
+
+	return &DNSKEY{K: dk, D: dk.ToDS(dns.SHA256), s: s, tag: tag}, nil
+}
+
 // getDNSKEY returns the correct DNSKEY to the client. Signatures are added when do is true.
 func (d Dnssec) getDNSKEY(state request.Request, zone string, do bool, server string) *dns.Msg {
 	keys := make([]dns.RR, len(d.keys))

plugin/dnssec/setup.go

@@ -141,6 +141,19 @@ func keyParse(c *caddy.Controller) ([]*DNSKEY, error) {
 			}
 			keys = append(keys, k)
 		}
+	} else if value == "secret" {
+		ks := c.RemainingArgs()
+		if len(ks) == 0 {
+			return nil, c.ArgErr()
+		}
+
+		for _, k := range ks {
+			k, err := ParseKeySecret(k)
+			if err != nil {
+				return nil, err
+			}
+			keys = append(keys, k)
+		}
 	}
 	return keys, nil
 }