Optimize decryptObjectInfo (#10726)

`decryptObjectInfo` is a significant bottleneck when listing objects.

Reduce the allocations for a significant speedup.

https://github.com/minio/sio/pull/40

```
λ benchcmp before.txt after.txt
benchmark                          old ns/op     new ns/op     delta
Benchmark_decryptObjectInfo-32     24260928      808656        -96.67%

benchmark                          old MB/s     new MB/s     speedup
Benchmark_decryptObjectInfo-32     0.04         1.24         31.00x

benchmark                          old allocs     new allocs     delta
Benchmark_decryptObjectInfo-32     75112          48996          -34.77%

benchmark                          old bytes     new bytes     delta
Benchmark_decryptObjectInfo-32     287694772     4228076       -98.53%
```

cmd/crypto/kes.go

@@ -177,11 +177,10 @@ func (kes *kesService) CreateKey(keyID string) error { return kes.client.CreateK
 // named key referenced by keyID. It also binds the generated key
 // cryptographically to the provided context.
 func (kes *kesService) GenerateKey(keyID string, ctx Context) (key [32]byte, sealedKey []byte, err error) {
-	var context bytes.Buffer
+	context := ctx.AppendTo(make([]byte, 0, 128))
-	ctx.WriteTo(&context)
 
 	var plainKey []byte
-	plainKey, sealedKey, err = kes.client.GenerateDataKey(keyID, context.Bytes())
+	plainKey, sealedKey, err = kes.client.GenerateDataKey(keyID, context)
 	if err != nil {
 		return key, nil, err
 	}
@@ -200,11 +199,10 @@ func (kes *kesService) GenerateKey(keyID string, ctx Context) (key [32]byte, sea
 // The context must be same context as the one provided while
 // generating the plaintext key / sealedKey.
 func (kes *kesService) UnsealKey(keyID string, sealedKey []byte, ctx Context) (key [32]byte, err error) {
-	var context bytes.Buffer
+	context := ctx.AppendTo(make([]byte, 0, 128))
-	ctx.WriteTo(&context)
 
 	var plainKey []byte
-	plainKey, err = kes.client.DecryptDataKey(keyID, sealedKey, context.Bytes())
+	plainKey, err = kes.client.DecryptDataKey(keyID, sealedKey, context)
 	if err != nil {
 		return key, err
 	}

cmd/crypto/key.go

@@ -103,7 +103,6 @@ func (key ObjectKey) Seal(extKey, iv [32]byte, domain, bucket, object string) Se
 func (key *ObjectKey) Unseal(extKey [32]byte, sealedKey SealedKey, domain, bucket, object string) error {
 	var (
 		unsealConfig sio.Config
-		decryptedKey bytes.Buffer
 	)
 	switch sealedKey.Algorithm {
 	default:
@@ -122,10 +121,9 @@ func (key *ObjectKey) Unseal(extKey [32]byte, sealedKey SealedKey, domain, bucke
 		unsealConfig = sio.Config{MinVersion: sio.Version10, Key: sha.Sum(nil)}
 	}
 
-	if n, err := sio.Decrypt(&decryptedKey, bytes.NewReader(sealedKey.Key[:]), unsealConfig); n != 32 || err != nil {
+	if out, err := sio.DecryptBuffer(key[:0], sealedKey.Key[:], unsealConfig); len(out) != 32 || err != nil {
 		return ErrSecretKeyMismatch
 	}
-	copy(key[:], decryptedKey.Bytes())
 	return nil
 }
 
@@ -165,11 +163,7 @@ func (key ObjectKey) UnsealETag(etag []byte) ([]byte, error) {
 	if !IsETagSealed(etag) {
 		return etag, nil
 	}
-	var buffer bytes.Buffer
 	mac := hmac.New(sha256.New, key[:])
 	mac.Write([]byte("SSE-etag"))
-	if _, err := sio.Decrypt(&buffer, bytes.NewReader(etag), sio.Config{Key: mac.Sum(nil)}); err != nil {
+	return sio.DecryptBuffer(make([]byte, 0, len(etag)), etag, sio.Config{Key: mac.Sum(nil)})
-		return nil, err
-	}
-	return buffer.Bytes(), nil
 }

cmd/crypto/kms.go

@@ -39,6 +39,8 @@ type Context map[string]string
 //
 // WriteTo sorts the context keys and writes the sorted
 // key-value pairs as canonical JSON object to w.
+//
+// Note that neither keys nor values are escaped for JSON.
 func (c Context) WriteTo(w io.Writer) (n int64, err error) {
 	sortedKeys := make(sort.StringSlice, 0, len(c))
 	for k := range c {
@@ -67,6 +69,53 @@ func (c Context) WriteTo(w io.Writer) (n int64, err error) {
 	return n + int64(nn), err
 }
 
+// AppendTo appends the context in a canonical from to dst.
+//
+// AppendTo sorts the context keys and writes the sorted
+// key-value pairs as canonical JSON object to w.
+//
+// Note that neither keys nor values are escaped for JSON.
+func (c Context) AppendTo(dst []byte) (output []byte) {
+	if len(c) == 0 {
+		return append(dst, '{', '}')
+	}
+
+	// out should not escape.
+	out := bytes.NewBuffer(dst)
+
+	// No need to copy+sort
+	if len(c) == 1 {
+		for k, v := range c {
+			out.WriteString(`{"`)
+			out.WriteString(k)
+			out.WriteString(`":"`)
+			out.WriteString(v)
+			out.WriteString(`"}`)
+		}
+		return out.Bytes()
+	}
+
+	sortedKeys := make([]string, 0, len(c))
+	for k := range c {
+		sortedKeys = append(sortedKeys, k)
+	}
+	sort.Strings(sortedKeys)
+
+	out.WriteByte('{')
+	for i, k := range sortedKeys {
+		out.WriteByte('"')
+		out.WriteString(k)
+		out.WriteString(`":"`)
+		out.WriteString(c[k])
+		out.WriteByte('"')
+		if i < len(sortedKeys)-1 {
+			out.WriteByte(',')
+		}
+	}
+	out.WriteByte('}')
+	return out.Bytes()
+}
+
 // KMS represents an active and authenticted connection
 // to a Key-Management-Service. It supports generating
 // data key generation and unsealing of KMS-generated
@@ -155,13 +204,12 @@ func (kms *masterKeyKMS) Info() (info KMSInfo) {
 
 func (kms *masterKeyKMS) UnsealKey(keyID string, sealedKey []byte, ctx Context) (key [32]byte, err error) {
 	var (
-		buffer     bytes.Buffer
 		derivedKey = kms.deriveKey(keyID, ctx)
 	)
-	if n, err := sio.Decrypt(&buffer, bytes.NewReader(sealedKey), sio.Config{Key: derivedKey[:]}); err != nil || n != 32 {
+	out, err := sio.DecryptBuffer(key[:0], sealedKey, sio.Config{Key: derivedKey[:]})
+	if err != nil || len(out) != 32 {
 		return key, err // TODO(aead): upgrade sio to use sio.Error
 	}
-	copy(key[:], buffer.Bytes())
 	return key, nil
 }
 
@@ -171,7 +219,7 @@ func (kms *masterKeyKMS) deriveKey(keyID string, context Context) (key [32]byte)
 	}
 	mac := hmac.New(sha256.New, kms.masterKey[:])
 	mac.Write([]byte(keyID))
-	context.WriteTo(mac)
+	mac.Write(context.AppendTo(make([]byte, 0, 128)))
 	mac.Sum(key[:0])
 	return key
 }

cmd/crypto/kms_test.go

@@ -16,6 +16,7 @@ package crypto
 
 import (
 	"bytes"
+	"fmt"
 	"path"
 	"strings"
 	"testing"
@@ -83,3 +84,32 @@ func TestContextWriteTo(t *testing.T) {
 		}
 	}
 }
+
+func TestContextAppendTo(t *testing.T) {
+	for i, test := range contextWriteToTests {
+		dst := make([]byte, 0, 1024)
+		dst = test.Context.AppendTo(dst)
+		if s := string(dst); s != test.ExpectedJSON {
+			t.Errorf("Test %d: JSON representation differ - got: '%s' want: '%s'", i, s, test.ExpectedJSON)
+		}
+		// Append one more
+		dst = test.Context.AppendTo(dst)
+		if s := string(dst); s != test.ExpectedJSON+test.ExpectedJSON {
+			t.Errorf("Test %d: JSON representation differ - got: '%s' want: '%s'", i, s, test.ExpectedJSON+test.ExpectedJSON)
+		}
+	}
+}
+
+func BenchmarkContext_AppendTo(b *testing.B) {
+	tests := []Context{{}, {"bucket": "warp-benchmark-bucket"}, {"0": "1", "-": "2", ".": "#"}, {"34trg": "dfioutr89", "ikjfdghkjf": "jkedfhgfjkhg", "sdfhsdjkh": "if88889", "asddsirfh804": "kjfdshgdfuhgfg78-45604586#$%"}}
+	for _, test := range tests {
+		b.Run(fmt.Sprintf("%d-elems", len(test)), func(b *testing.B) {
+			dst := make([]byte, 0, 1024)
+			b.ReportAllocs()
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				dst = test.AppendTo(dst[:0])
+			}
+		})
+	}
+}

cmd/crypto/metadata.go

@@ -204,15 +204,17 @@ func (s3) ParseMetadata(metadata map[string]string) (keyID string, kmsKey []byte
 	}
 
 	// Check whether all extracted values are well-formed
-	iv, err := base64.StdEncoding.DecodeString(b64IV)
+	var iv [32]byte
-	if err != nil || len(iv) != 32 {
+	n, err := base64.StdEncoding.Decode(iv[:], []byte(b64IV))
+	if err != nil || n != 32 {
 		return keyID, kmsKey, sealedKey, errInvalidInternalIV
 	}
 	if algorithm != SealAlgorithm {
 		return keyID, kmsKey, sealedKey, errInvalidInternalSealAlgorithm
 	}
-	encryptedKey, err := base64.StdEncoding.DecodeString(b64SealedKey)
+	var encryptedKey [64]byte
-	if err != nil || len(encryptedKey) != 64 {
+	n, err = base64.StdEncoding.Decode(encryptedKey[:], []byte(b64SealedKey))
+	if err != nil || n != 64 {
 		return keyID, kmsKey, sealedKey, Errorf("The internal sealed key for SSE-S3 is invalid")
 	}
 	if idPresent && kmsKeyPresent { // We are using a KMS -> parse the sealed KMS data key.
@@ -223,8 +225,8 @@ func (s3) ParseMetadata(metadata map[string]string) (keyID string, kmsKey []byte
 	}
 
 	sealedKey.Algorithm = algorithm
-	copy(sealedKey.IV[:], iv)
+	sealedKey.IV = iv
-	copy(sealedKey.Key[:], encryptedKey)
+	sealedKey.Key = encryptedKey
 	return keyID, kmsKey, sealedKey, nil
 }
 

cmd/crypto/vault.go

@@ -15,7 +15,6 @@
 package crypto
 
 import (
-	"bytes"
 	"encoding/base64"
 	"errors"
 	"fmt"
@@ -224,11 +223,10 @@ func (v *vaultService) CreateKey(keyID string) error {
 // named key referenced by keyID. It also binds the generated key
 // cryptographically to the provided context.
 func (v *vaultService) GenerateKey(keyID string, ctx Context) (key [32]byte, sealedKey []byte, err error) {
-	var contextStream bytes.Buffer
+	context := ctx.AppendTo(make([]byte, 0, 128))
-	ctx.WriteTo(&contextStream)
 
 	payload := map[string]interface{}{
-		"context": base64.StdEncoding.EncodeToString(contextStream.Bytes()),
+		"context": base64.StdEncoding.EncodeToString(context),
 	}
 	s, err := v.client.Logical().Write(fmt.Sprintf("/transit/datakey/plaintext/%s", keyID), payload)
 	if err != nil {
@@ -260,12 +258,11 @@ func (v *vaultService) GenerateKey(keyID string, ctx Context) (key [32]byte, sea
 // The context must be same context as the one provided while
 // generating the plaintext key / sealedKey.
 func (v *vaultService) UnsealKey(keyID string, sealedKey []byte, ctx Context) (key [32]byte, err error) {
-	var contextStream bytes.Buffer
+	context := ctx.AppendTo(make([]byte, 0, 128))
-	ctx.WriteTo(&contextStream)
 
 	payload := map[string]interface{}{
 		"ciphertext": string(sealedKey),
-		"context":    base64.StdEncoding.EncodeToString(contextStream.Bytes()),
+		"context":    base64.StdEncoding.EncodeToString(context),
 	}
 
 	s, err := v.client.Logical().Write(fmt.Sprintf("/transit/decrypt/%s", keyID), payload)
@@ -294,12 +291,11 @@ func (v *vaultService) UnsealKey(keyID string, sealedKey []byte, ctx Context) (k
 // The context must be same context as the one provided while
 // generating the plaintext key / sealedKey.
 func (v *vaultService) UpdateKey(keyID string, sealedKey []byte, ctx Context) (rotatedKey []byte, err error) {
-	var contextStream bytes.Buffer
+	context := ctx.AppendTo(make([]byte, 0, 128))
-	ctx.WriteTo(&contextStream)
 
 	payload := map[string]interface{}{
 		"ciphertext": string(sealedKey),
-		"context":    base64.StdEncoding.EncodeToString(contextStream.Bytes()),
+		"context":    base64.StdEncoding.EncodeToString(context),
 	}
 	s, err := v.client.Logical().Write(fmt.Sprintf("/transit/rewrap/%s", keyID), payload)
 	if err != nil {

cmd/encryption-v1_test.go

@@ -19,10 +19,14 @@ package cmd
 import (
 	"bytes"
 	"encoding/base64"
+	"encoding/json"
+	"fmt"
 	"net/http"
+	"os"
 	"testing"
 
 	humanize "github.com/dustin/go-humanize"
+	"github.com/klauspost/compress/zstd"
 	"github.com/minio/minio-go/v7/pkg/encrypt"
 	"github.com/minio/minio/cmd/crypto"
 	"github.com/minio/sio"
@@ -622,3 +626,89 @@ func TestGetDefaultOpts(t *testing.T) {
 		}
 	}
 }
+func Test_decryptObjectInfo(t *testing.T) {
+	var testSet []struct {
+		Bucket  string
+		Name    string
+		UserDef map[string]string
+	}
+	file, err := os.Open("testdata/decryptObjectInfo.json.zst")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer file.Close()
+	dec, err := zstd.NewReader(file)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dec.Close()
+	js := json.NewDecoder(dec)
+	err = js.Decode(&testSet)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	os.Setenv("MINIO_KMS_MASTER_KEY", "my-minio-key:6368616e676520746869732070617373776f726420746f206120736563726574")
+	defer os.Setenv("MINIO_KMS_MASTER_KEY", "")
+	GlobalKMS, err = crypto.NewKMS(crypto.KMSConfig{})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var dst [32]byte
+	for i := range testSet {
+		t.Run(fmt.Sprint("case-", i), func(t *testing.T) {
+			test := &testSet[i]
+			_, err := decryptObjectInfo(dst[:], test.Bucket, test.Name, test.UserDef)
+			if err != nil {
+				t.Fatal(err)
+			}
+		})
+	}
+}
+
+func Benchmark_decryptObjectInfo(b *testing.B) {
+	var testSet []struct {
+		Bucket  string
+		Name    string
+		UserDef map[string]string
+	}
+	file, err := os.Open("testdata/decryptObjectInfo.json.zst")
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer file.Close()
+	dec, err := zstd.NewReader(file)
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer dec.Close()
+	js := json.NewDecoder(dec)
+	err = js.Decode(&testSet)
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	os.Setenv("MINIO_KMS_MASTER_KEY", "my-minio-key:6368616e676520746869732070617373776f726420746f206120736563726574")
+	defer os.Setenv("MINIO_KMS_MASTER_KEY", "")
+	GlobalKMS, err = crypto.NewKMS(crypto.KMSConfig{})
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	b.ReportAllocs()
+	b.ResetTimer()
+	b.SetBytes(int64(len(testSet)))
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			var dst [32]byte
+			for i := range testSet {
+				test := &testSet[i]
+				_, err := decryptObjectInfo(dst[:], test.Bucket, test.Name, test.UserDef)
+				if err != nil {
+					b.Fatal(err)
+				}
+			}
+		}
+	})
+}

go.mod

@@ -52,7 +52,7 @@ require (
 	github.com/minio/selfupdate v0.3.1
 	github.com/minio/sha256-simd v0.1.1
 	github.com/minio/simdjson-go v0.1.5
-	github.com/minio/sio v0.2.0
+	github.com/minio/sio v0.2.1
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/mmcloughlin/avo v0.0.0-20200803215136-443f81d77104 // indirect
 	github.com/montanaflynn/stats v0.5.0

go.sum

@@ -318,6 +318,8 @@ github.com/minio/simdjson-go v0.1.5 h1:6T5mHh7r3kUvgwhmFWQAjoPV5Yt5oD/VPjAI9ViH1
 github.com/minio/simdjson-go v0.1.5/go.mod h1:oKURrZZEBtqObgJrSjN1Ln2n9MJj2icuBTkeJzZnvSI=
 github.com/minio/sio v0.2.0 h1:NCRCFLx0r5pRbXf65LVNjxbCGZgNQvNFQkgX3XF4BoA=
 github.com/minio/sio v0.2.0/go.mod h1:nKM5GIWSrqbOZp0uhyj6M1iA0X6xQzSGtYSaTKSCut0=
+github.com/minio/sio v0.2.1 h1:NjzKiIMSMcHediVQR0AFVx2tp7Wxh9tKPfDI3kH7aHQ=
+github.com/minio/sio v0.2.1/go.mod h1:8b0yPp2avGThviy/+OCJBI6OMpvxoUuiLvE6F1lebhw=
 github.com/mitchellh/cli v1.0.0/go.mod h1:hNIlj7HEI86fIcpObd7a0FcrxTWetlwJDGcceTlRvqc=
 github.com/mitchellh/copystructure v1.0.0/go.mod h1:SNtv71yrdKgLRyLFxmLdkAbkKEFWgYaq1OVrnRcwhnw=
 github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG+4E0Y=