Migrate this project to minio micro services code

pkg/fs/signature.go

@@ -0,0 +1,327 @@
+/*
+ * Minio Cloud Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package fs
+
+import (
+	"bytes"
+	"crypto/hmac"
+	"encoding/hex"
+	"net/http"
+	"net/url"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"github.com/minio/minio-xl/pkg/crypto/sha256"
+	"github.com/minio/minio-xl/pkg/probe"
+)
+
+// Signature - local variables
+type Signature struct {
+	AccessKeyID     string
+	SecretAccessKey string
+	Presigned       bool
+	PresignedPolicy string
+	SignedHeaders   []string
+	Signature       string
+	Request         *http.Request
+}
+
+const (
+	authHeaderPrefix = "AWS4-HMAC-SHA256"
+	iso8601Format    = "20060102T150405Z"
+	yyyymmdd         = "20060102"
+)
+
+// sumHMAC calculate hmac between two input byte array
+func sumHMAC(key []byte, data []byte) []byte {
+	hash := hmac.New(sha256.New, key)
+	hash.Write(data)
+	return hash.Sum(nil)
+}
+
+// getURLEncodedName encode the strings from UTF-8 byte representations to HTML hex escape sequences
+//
+// This is necessary since regular url.Parse() and url.Encode() functions do not support UTF-8
+// non english characters cannot be parsed due to the nature in which url.Encode() is written
+//
+// This function on the other hand is a direct replacement for url.Encode() technique to support
+// pretty much every UTF-8 character.
+func getURLEncodedName(name string) string {
+	// if object matches reserved string, no need to encode them
+	reservedNames := regexp.MustCompile("^[a-zA-Z0-9-_.~/]+$")
+	if reservedNames.MatchString(name) {
+		return name
+	}
+	var encodedName string
+	for _, s := range name {
+		if 'A' <= s && s <= 'Z' || 'a' <= s && s <= 'z' || '0' <= s && s <= '9' { // §2.3 Unreserved characters (mark)
+			encodedName = encodedName + string(s)
+			continue
+		}
+		switch s {
+		case '-', '_', '.', '~', '/': // §2.3 Unreserved characters (mark)
+			encodedName = encodedName + string(s)
+			continue
+		default:
+			len := utf8.RuneLen(s)
+			if len < 0 {
+				return name
+			}
+			u := make([]byte, len)
+			utf8.EncodeRune(u, s)
+			for _, r := range u {
+				hex := hex.EncodeToString([]byte{r})
+				encodedName = encodedName + "%" + strings.ToUpper(hex)
+			}
+		}
+	}
+	return encodedName
+}
+
+// getCanonicalHeaders generate a list of request headers with their values
+func (r Signature) getCanonicalHeaders(signedHeaders map[string][]string) string {
+	var headers []string
+	vals := make(map[string][]string)
+	for k, vv := range signedHeaders {
+		headers = append(headers, strings.ToLower(k))
+		vals[strings.ToLower(k)] = vv
+	}
+	headers = append(headers, "host")
+	sort.Strings(headers)
+
+	var buf bytes.Buffer
+	for _, k := range headers {
+		buf.WriteString(k)
+		buf.WriteByte(':')
+		switch {
+		case k == "host":
+			buf.WriteString(r.Request.Host)
+			fallthrough
+		default:
+			for idx, v := range vals[k] {
+				if idx > 0 {
+					buf.WriteByte(',')
+				}
+				buf.WriteString(v)
+			}
+			buf.WriteByte('\n')
+		}
+	}
+	return buf.String()
+}
+
+// getSignedHeaders generate a string i.e alphabetically sorted, semicolon-separated list of lowercase request header names
+func (r Signature) getSignedHeaders(signedHeaders map[string][]string) string {
+	var headers []string
+	for k := range signedHeaders {
+		headers = append(headers, strings.ToLower(k))
+	}
+	headers = append(headers, "host")
+	sort.Strings(headers)
+	return strings.Join(headers, ";")
+}
+
+// extractSignedHeaders extract signed headers from Authorization header
+func (r Signature) extractSignedHeaders() map[string][]string {
+	extractedSignedHeadersMap := make(map[string][]string)
+	for _, header := range r.SignedHeaders {
+		val, ok := r.Request.Header[http.CanonicalHeaderKey(header)]
+		if !ok {
+			// if not found continue, we will fail later
+			continue
+		}
+		extractedSignedHeadersMap[header] = val
+	}
+	return extractedSignedHeadersMap
+}
+
+// getCanonicalRequest generate a canonical request of style
+//
+// canonicalRequest =
+//  <HTTPMethod>\n
+//  <CanonicalURI>\n
+//  <CanonicalQueryString>\n
+//  <CanonicalHeaders>\n
+//  <SignedHeaders>\n
+//  <HashedPayload>
+//
+func (r *Signature) getCanonicalRequest() string {
+	payload := r.Request.Header.Get(http.CanonicalHeaderKey("x-amz-content-sha256"))
+	r.Request.URL.RawQuery = strings.Replace(r.Request.URL.Query().Encode(), "+", "%20", -1)
+	encodedPath := getURLEncodedName(r.Request.URL.Path)
+	// convert any space strings back to "+"
+	encodedPath = strings.Replace(encodedPath, "+", "%20", -1)
+	canonicalRequest := strings.Join([]string{
+		r.Request.Method,
+		encodedPath,
+		r.Request.URL.RawQuery,
+		r.getCanonicalHeaders(r.extractSignedHeaders()),
+		r.getSignedHeaders(r.extractSignedHeaders()),
+		payload,
+	}, "\n")
+	return canonicalRequest
+}
+
+// getCanonicalRequest generate a canonical request of style
+//
+// canonicalRequest =
+//  <HTTPMethod>\n
+//  <CanonicalURI>\n
+//  <CanonicalQueryString>\n
+//  <CanonicalHeaders>\n
+//  <SignedHeaders>\n
+//  <HashedPayload>
+//
+func (r Signature) getPresignedCanonicalRequest(presignedQuery string) string {
+	rawQuery := strings.Replace(presignedQuery, "+", "%20", -1)
+	encodedPath := getURLEncodedName(r.Request.URL.Path)
+	// convert any space strings back to "+"
+	encodedPath = strings.Replace(encodedPath, "+", "%20", -1)
+	canonicalRequest := strings.Join([]string{
+		r.Request.Method,
+		encodedPath,
+		rawQuery,
+		r.getCanonicalHeaders(r.extractSignedHeaders()),
+		r.getSignedHeaders(r.extractSignedHeaders()),
+		"UNSIGNED-PAYLOAD",
+	}, "\n")
+	return canonicalRequest
+}
+
+// getScope generate a string of a specific date, an AWS region, and a service
+func (r Signature) getScope(t time.Time) string {
+	scope := strings.Join([]string{
+		t.Format(yyyymmdd),
+		"milkyway",
+		"s3",
+		"aws4_request",
+	}, "/")
+	return scope
+}
+
+// getStringToSign a string based on selected query values
+func (r Signature) getStringToSign(canonicalRequest string, t time.Time) string {
+	stringToSign := authHeaderPrefix + "\n" + t.Format(iso8601Format) + "\n"
+	stringToSign = stringToSign + r.getScope(t) + "\n"
+	stringToSign = stringToSign + hex.EncodeToString(sha256.Sum256([]byte(canonicalRequest)))
+	return stringToSign
+}
+
+// getSigningKey hmac seed to calculate final signature
+func (r Signature) getSigningKey(t time.Time) []byte {
+	secret := r.SecretAccessKey
+	date := sumHMAC([]byte("AWS4"+secret), []byte(t.Format(yyyymmdd)))
+	region := sumHMAC(date, []byte("milkyway"))
+	service := sumHMAC(region, []byte("s3"))
+	signingKey := sumHMAC(service, []byte("aws4_request"))
+	return signingKey
+}
+
+// getSignature final signature in hexadecimal form
+func (r Signature) getSignature(signingKey []byte, stringToSign string) string {
+	return hex.EncodeToString(sumHMAC(signingKey, []byte(stringToSign)))
+}
+
+// DoesPolicySignatureMatch - Verify query headers with post policy
+//     - http://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-HTTPPOSTConstructPolicy.html
+// returns true if matches, false otherwise. if error is not nil then it is always false
+func (r *Signature) DoesPolicySignatureMatch(date string) (bool, *probe.Error) {
+	t, err := time.Parse(iso8601Format, date)
+	if err != nil {
+		return false, probe.NewError(err)
+	}
+	signingKey := r.getSigningKey(t)
+	stringToSign := string(r.PresignedPolicy)
+	newSignature := r.getSignature(signingKey, stringToSign)
+	if newSignature != r.Signature {
+		return false, nil
+	}
+	return true, nil
+}
+
+// DoesPresignedSignatureMatch - Verify query headers with presigned signature
+//     - http://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-query-string-auth.html
+// returns true if matches, false otherwise. if error is not nil then it is always false
+func (r *Signature) DoesPresignedSignatureMatch() (bool, *probe.Error) {
+	query := make(url.Values)
+	query.Set("X-Amz-Algorithm", authHeaderPrefix)
+
+	var date string
+	if date = r.Request.URL.Query().Get("X-Amz-Date"); date == "" {
+		return false, probe.NewError(MissingDateHeader{})
+	}
+	t, err := time.Parse(iso8601Format, date)
+	if err != nil {
+		return false, probe.NewError(err)
+	}
+	if _, ok := r.Request.URL.Query()["X-Amz-Expires"]; !ok {
+		return false, probe.NewError(MissingExpiresQuery{})
+	}
+	expireSeconds, err := strconv.Atoi(r.Request.URL.Query().Get("X-Amz-Expires"))
+	if err != nil {
+		return false, probe.NewError(err)
+	}
+	if time.Now().UTC().Sub(t) > time.Duration(expireSeconds)*time.Second {
+		return false, probe.NewError(ExpiredPresignedRequest{})
+	}
+	query.Set("X-Amz-Date", t.Format(iso8601Format))
+	query.Set("X-Amz-Expires", strconv.Itoa(expireSeconds))
+	query.Set("X-Amz-SignedHeaders", r.getSignedHeaders(r.extractSignedHeaders()))
+	query.Set("X-Amz-Credential", r.AccessKeyID+"/"+r.getScope(t))
+
+	encodedQuery := query.Encode()
+	newSignature := r.getSignature(r.getSigningKey(t), r.getStringToSign(r.getPresignedCanonicalRequest(encodedQuery), t))
+	encodedQuery += "&X-Amz-Signature=" + newSignature
+
+	if encodedQuery != r.Request.URL.RawQuery {
+		return false, nil
+	}
+	return true, nil
+}
+
+// DoesSignatureMatch - Verify authorization header with calculated header in accordance with
+//     - http://docs.aws.amazon.com/AmazonS3/latest/API/sig-v4-authenticating-requests.html
+// returns true if matches, false otherwise. if error is not nil then it is always false
+func (r *Signature) DoesSignatureMatch(hashedPayload string) (bool, *probe.Error) {
+	// set new calulated payload
+	r.Request.Header.Set("X-Amz-Content-Sha256", hashedPayload)
+
+	// Add date if not present throw error
+	var date string
+	if date = r.Request.Header.Get(http.CanonicalHeaderKey("x-amz-date")); date == "" {
+		if date = r.Request.Header.Get("Date"); date == "" {
+			return false, probe.NewError(MissingDateHeader{})
+		}
+	}
+	t, err := time.Parse(iso8601Format, date)
+	if err != nil {
+		return false, probe.NewError(err)
+	}
+	canonicalRequest := r.getCanonicalRequest()
+	stringToSign := r.getStringToSign(canonicalRequest, t)
+	signingKey := r.getSigningKey(t)
+	newSignature := r.getSignature(signingKey, stringToSign)
+
+	if newSignature != r.Signature {
+		return false, nil
+	}
+	return true, nil
+}