simple macaroon implementation

authorize secret usage with macaroons

use our newly opensourced macaroons implementation instead of a new one

more caveats

command for generating macaroon

.gitignore

@@ -1,3 +1,4 @@
+.vscode
 *.pem
 /bin/*
 /.envrc

authorizer.go

@@ -1,14 +1,18 @@
 package tokenizer
 
 import (
+	"bytes"
 	"crypto/sha256"
 	"crypto/subtle"
 	"encoding/base64"
+	"encoding/hex"
 	"fmt"
 	"net/http"
 	"strings"
 
 	"github.com/sirupsen/logrus"
+	"github.com/superfly/macaroon"
+	tkmac "github.com/superfly/tokenizer/macaroon"
 )
 
 const headerProxyAuthorization = "Proxy-Authorization"
@@ -29,8 +33,87 @@ func NewBearerAuthConfig(token string) *BearerAuthConfig {
 var _ AuthConfig = new(BearerAuthConfig)
 
 func (c *BearerAuthConfig) AuthRequest(req *http.Request) error {
-	var found bool
+	for _, tok := range proxyAuthorizationTokens(req) {
+		hdrDigest := sha256.Sum256([]byte(tok))
+		if subtle.ConstantTimeCompare(c.Digest, hdrDigest[:]) == 1 {
+			return nil
+		}
+	}
+
+	return fmt.Errorf("%w: bad or missing proxy auth", ErrNotAuthorized)
+}
+
+type MacaroonAuthConfig struct {
+	Key []byte `json:"key"`
+}
+
+func NewMacaroonAuthConfig(key []byte) *MacaroonAuthConfig {
+	return &MacaroonAuthConfig{Key: key}
+}
+
+var _ AuthConfig = new(MacaroonAuthConfig)
+
+func (c *MacaroonAuthConfig) AuthRequest(req *http.Request) error {
+	var (
+		expectedKID = tkmac.KeyFingerprint(c.Key)
+		log         = logrus.WithField("expected-kid", hex.EncodeToString(expectedKID))
+	)
+
+	for _, tok := range proxyAuthorizationTokens(req) {
+		permission, discharges, err := macaroon.ParsePermissionAndDischargeTokens(tok, tkmac.Location)
+		if err != nil {
+			log.WithError(err).Warn("bad macaroon encoding")
+			continue
+		}
+
+		m, err := macaroon.Decode(permission)
+		if err != nil {
+			log.WithError(err).Warn("bad macaroon format")
+			continue
+		}
+		log = log.WithFields(logrus.Fields{"uuid": m.Nonce.UUID()})
+
+		if !bytes.Equal(m.Nonce.KID, expectedKID) {
+			log.WithField("kid", hex.EncodeToString(m.Nonce.KID)).Warn("wrong  macaroon key")
+			continue
+		}
+
+		cavs, err := m.Verify(c.Key, discharges, nil)
+		if err != nil {
+			log.WithError(err).Warn("bad macaroon signature")
+			continue
+		}
+
+		if err = cavs.Validate(&tkmac.Access{Request: req}); err != nil {
+			log.WithError(err).Warn("bad macaroon authz")
+			continue
+		}
+
+		return nil
+	}
+
+	return fmt.Errorf("%w: bad or missing proxy auth", ErrNotAuthorized)
+}
+
+func (c *MacaroonAuthConfig) Macaroon(caveats ...macaroon.Caveat) (string, error) {
+	m, err := macaroon.New(tkmac.KeyFingerprint(c.Key), tkmac.Location, c.Key)
+	if err != nil {
+		return "", err
+	}
 
+	if err := m.Add(caveats...); err != nil {
+		return "", err
+	}
+
+	mb, err := m.Encode()
+	if err != nil {
+		return "", err
+	}
+
+	return macaroon.ToAuthorizationHeader(mb), nil
+}
+
+func proxyAuthorizationTokens(req *http.Request) (ret []string) {
 hdrLoop:
 	for _, hdr := range req.Header.Values(headerProxyAuthorization) {
 		scheme, rest, ok := strings.Cut(hdr, " ")
@@ -40,7 +123,7 @@ hdrLoop:
 		}
 
 		switch scheme {
-		case "Bearer":
+		case "Bearer", "FlyV1":
 			hdr = rest
 		case "Basic":
 			raw, err := base64.StdEncoding.DecodeString(rest)
@@ -59,14 +142,8 @@ hdrLoop:
 			continue hdrLoop
 		}
 
-		hdrDigest := sha256.Sum256([]byte(hdr))
-		if subtle.ConstantTimeCompare(c.Digest, hdrDigest[:]) == 1 {
-			found = true
-		}
-	}
-	if !found {
-		return fmt.Errorf("%w: bad or missing proxy auth", ErrNotAuthorized)
+		ret = append(ret, hdr)
 	}
 
-	return nil
+	return
 }

client.go

@@ -47,11 +47,15 @@ func WithSecret(sealedSecret string, params map[string]string) ClientOption {
 }
 
 func WithAuth(auth string) ClientOption {
+	if len(auth) < 6 || auth[:6] != "FlyV1 " {
+		auth = fmt.Sprintf("Bearer %s", auth)
+	}
+
 	return func(co *clientOptions) {
 		if co.headers == nil {
 			co.headers = make(http.Header)
 		}
-		co.headers.Add(headerProxyAuthorization, fmt.Sprintf("Bearer %s", auth))
+		co.headers.Add(headerProxyAuthorization, auth)
 	}
 }
 

cmd/curl/main.go

@@ -8,25 +8,30 @@ import (
 	"net/url"
 	"os"
 
+	"github.com/superfly/macaroon"
 	"github.com/superfly/tokenizer"
+	tkmac "github.com/superfly/tokenizer/macaroon"
 )
 
 func main() {
 	if len(os.Args) < 2 {
 		usage()
 	}
 
-	if os.Args[1] == "gen" {
+	switch os.Args[1] {
+	case "gen":
 		if len(os.Args) != 3 {
 			usage()
 		}
 		doGenerateSecret(os.Args[2])
+	case "gen-macaroon":
+		doGenerateMacararoon()
+	default:
+		if _, err := url.Parse(os.Args[1]); err != nil {
+			usage()
+		}
+		doCurl(os.Args[1])
 	}
-
-	if _, err := url.Parse(os.Args[1]); err != nil {
-		usage()
-	}
-	doCurl(os.Args[1])
 }
 
 func doCurl(url string) {
@@ -57,10 +62,44 @@ func doCurl(url string) {
 
 func doGenerateSecret(secretToken string) {
 	var (
-		sealKey   = mustGetEnv("SEAL_KEY")
-		authToken = randHex(8)
-		secret    = &tokenizer.Secret{
-			AuthConfig:      tokenizer.NewBearerAuthConfig(authToken),
+		sealKey        = mustGetEnv("SEAL_KEY")
+		authToken      = os.Getenv("AUTH_TOKEN")
+		hexMacaroonKey = os.Getenv("MACAROON_KEY")
+	)
+
+	if authToken != "" && hexMacaroonKey != "" {
+		fatalln("cannot specify AUTH_TOKEN and MACAROON_KEY")
+	}
+
+	var authConfig tokenizer.AuthConfig
+	if hexMacaroonKey != "" {
+		key, err := hex.DecodeString(hexMacaroonKey)
+		if err != nil {
+			fatalf("MACAROON_KEY must be hex encoded: %s", err)
+		}
+
+		mac, err := macaroon.New(tkmac.KeyFingerprint(key), tkmac.Location, key)
+		if err != nil {
+			fatalf("failed to generate macaroon: %s", err)
+		}
+
+		tok, err := mac.Encode()
+		if err != nil {
+			fatalf("failed to encode macaroon: %s", err)
+		}
+
+		authToken = macaroon.ToAuthorizationHeader(tok)
+		authConfig = tokenizer.NewMacaroonAuthConfig(key)
+	} else {
+		if authToken == "" {
+			authToken = randHex(8)
+		}
+		authConfig = tokenizer.NewBearerAuthConfig(authToken)
+	}
+
+	var (
+		secret = &tokenizer.Secret{
+			AuthConfig:      authConfig,
 			ProcessorConfig: &tokenizer.InjectProcessorConfig{Token: secretToken},
 		}
 	)
@@ -74,6 +113,27 @@ func doGenerateSecret(secretToken string) {
 	os.Exit(0)
 }
 
+func doGenerateMacararoon() {
+	hexMacaroonKey := mustGetEnv("MACAROON_KEY")
+	macaroonKey, err := hex.DecodeString(hexMacaroonKey)
+	if err != nil {
+		fatalf("bad MACAROON_KEY: %s", err)
+	}
+
+	m, err := macaroon.New(tkmac.KeyFingerprint(macaroonKey), tkmac.Location, macaroonKey)
+	if err != nil {
+		fatalf("failed to generate macaroon: %s", err)
+	}
+
+	tok, err := m.Encode()
+	if err != nil {
+		fatalf("failed to generate macaroon: %s", err)
+	}
+
+	fmt.Printf("export AUTH_TOKEN=\"%s\"\n", macaroon.ToAuthorizationHeader(tok))
+	os.Exit(0)
+}
+
 func mustGetEnv(key string) string {
 	val := os.Getenv(key)
 	if val == "" {

go.mod

@@ -6,12 +6,16 @@ require (
 	github.com/alecthomas/assert/v2 v2.2.2
 	github.com/elazarl/goproxy v0.0.0-20230731152917-f99041a5c027
 	github.com/sirupsen/logrus v1.9.3
-	golang.org/x/crypto v0.11.0
-	golang.org/x/exp v0.0.0-20230626212559-97b1e661b5df
+	github.com/superfly/macaroon v0.0.5
+	golang.org/x/crypto v0.12.0
+	golang.org/x/exp v0.0.0-20230713183714-613f0c0eb8a1
 )
 
 require (
 	github.com/alecthomas/repr v0.2.0 // indirect
+	github.com/google/uuid v1.3.0 // indirect
 	github.com/hexops/gotextdiff v1.0.3 // indirect
-	golang.org/x/sys v0.10.0 // indirect
+	github.com/vmihailenco/msgpack/v5 v5.3.5 // indirect
+	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
+	golang.org/x/sys v0.11.0 // indirect
 )

go.sum

@@ -9,6 +9,8 @@ github.com/elazarl/goproxy v0.0.0-20230731152917-f99041a5c027 h1:1L0aalTpPz7YlMx
 github.com/elazarl/goproxy v0.0.0-20230731152917-f99041a5c027/go.mod h1:Ro8st/ElPeALwNFlcTpWmkr6IoMFfkjXAvTHpevnDsM=
 github.com/elazarl/goproxy/ext v0.0.0-20190711103511-473e67f1d7d2 h1:dWB6v3RcOy03t/bUadywsbyrQwCqZeNIEX6M1OtSZOM=
 github.com/elazarl/goproxy/ext v0.0.0-20190711103511-473e67f1d7d2/go.mod h1:gNh8nYJoAm43RfaxurUnxr+N1PwuFV3ZMl/efxlIlY8=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
 github.com/hexops/gotextdiff v1.0.3/go.mod h1:pSWU5MAI3yDq+fZBTazCSJysOMbxWL1BSow5/V2vxeg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -17,15 +19,22 @@ github.com/rogpeppe/go-charset v0.0.0-20180617210344-2471d30d28b4/go.mod h1:qgYe
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
 github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-golang.org/x/crypto v0.11.0 h1:6Ewdq3tDic1mg5xRO4milcWCfMVQhI4NkqWWvqejpuA=
-golang.org/x/crypto v0.11.0/go.mod h1:xgJhtzW8F9jGdVFWZESrid1U1bjeNy4zgy5cRr/CIio=
-golang.org/x/exp v0.0.0-20230626212559-97b1e661b5df h1:UA2aFVmmsIlefxMk29Dp2juaUSth8Pyn3Tq5Y5mJGME=
-golang.org/x/exp v0.0.0-20230626212559-97b1e661b5df/go.mod h1:FXUEEKJgO7OQYeo8N01OfiKP8RXMtf6e8aTskBGqWdc=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/superfly/macaroon v0.0.5 h1:Rw48kdYc2k0PHccGnNWO0Byc5TQoJBjbQtzGZJPFKcU=
+github.com/superfly/macaroon v0.0.5/go.mod h1:5DZuLe1e3EiEDs9R7snKQJVslVjgBhlJ9jbnOmKasRg=
+github.com/vmihailenco/msgpack/v5 v5.3.5 h1:5gO0H1iULLWGhs2H5tbAHIZTV8/cYafcFOr9znI5mJU=
+github.com/vmihailenco/msgpack/v5 v5.3.5/go.mod h1:7xyJ9e+0+9SaZT0Wt1RGleJXzli6Q/V5KbhBonMG9jc=
+github.com/vmihailenco/tagparser/v2 v2.0.0 h1:y09buUbR+b5aycVFQs/g70pqKVZNBmxwAhO7/IwNM9g=
+github.com/vmihailenco/tagparser/v2 v2.0.0/go.mod h1:Wri+At7QHww0WTrCBeu4J6bNtoV6mEfg5OIWRZA9qds=
+golang.org/x/crypto v0.12.0 h1:tFM/ta59kqch6LlvYnPa0yx5a83cL2nHflFhYKvv9Yk=
+golang.org/x/crypto v0.12.0/go.mod h1:NF0Gs7EO5K4qLn+Ylc+fih8BSTeIjAP05siRnAh98yw=
+golang.org/x/exp v0.0.0-20230713183714-613f0c0eb8a1 h1:MGwJjxBy0HJshjDNfLsYO8xppfqWlA5ZT9OhtUUhTNw=
+golang.org/x/exp v0.0.0-20230713183714-613f0c0eb8a1/go.mod h1:FXUEEKJgO7OQYeo8N01OfiKP8RXMtf6e8aTskBGqWdc=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.10.0 h1:SqMFp9UcQJZa+pmYuAKjd9xq1f0j5rLcDIk0mj4qAsA=
-golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.11.0 h1:eG7RXZHdqOJ1i+0lgLgCpSXAp6M3LYlAo6osgSi0xOM=
+golang.org/x/sys v0.11.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

macaroon/access.go

@@ -0,0 +1,25 @@
+package macaroon
+
+import (
+	"net/http"
+	"time"
+
+	"github.com/superfly/macaroon"
+)
+
+type Access struct {
+	Request *http.Request
+}
+
+var _ macaroon.Access = (*Access)(nil)
+
+func (a *Access) Now() time.Time {
+	return time.Now()
+}
+
+func (a *Access) Validate() error {
+	if a.Request == nil {
+		return macaroon.ErrInvalidAccess
+	}
+	return nil
+}