Add server side signaturev4 check, not wired up to the readers yet.

pkg/donut/errors.go

@@ -309,3 +309,20 @@ type InvalidUploadID struct {
 func (e InvalidUploadID) Error() string {
 	return "Invalid upload id " + e.UploadID
 }
+
+// SignatureDoesNotMatch invalid signature
+type SignatureDoesNotMatch struct {
+	SignatureSent       string
+	SignatureCalculated string
+}
+
+func (e SignatureDoesNotMatch) Error() string {
+	return "The request signature we calculated does not match the signature you provided"
+}
+
+// MissingDateHeader date header missing
+type MissingDateHeader struct{}
+
+func (e MissingDateHeader) Error() string {
+	return "Missing date header"
+}

pkg/donut/signature-v4.go

@@ -0,0 +1,269 @@
+/*
+ * Minimalist Object 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 donut
+
+import (
+	"bytes"
+	"crypto/hmac"
+	"encoding/hex"
+	"errors"
+	"io"
+	"net/http"
+	"regexp"
+	"sort"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"github.com/minio/minio/pkg/auth"
+	"github.com/minio/minio/pkg/crypto/sha256"
+	"github.com/minio/minio/pkg/iodine"
+)
+
+// request - a http request
+type request struct {
+	receivedReq   *http.Request
+	calculatedReq *http.Request
+	user          *auth.User
+	body          io.Reader
+}
+
+const (
+	authHeader    = "AWS4-HMAC-SHA256"
+	iso8601Format = "20060102T150405Z"
+	yyyymmdd      = "20060102"
+)
+
+var ignoredHeaders = map[string]bool{
+	"Authorization":  true,
+	"Content-Type":   true,
+	"Content-Length": true,
+	"User-Agent":     true,
+}
+
+// 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)
+}
+
+// urlEncodedName 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 urlEncodeName(name string) (string, error) {
+	// if object matches reserved string, no need to encode them
+	reservedNames := regexp.MustCompile("^[a-zA-Z0-9-_.~/]+$")
+	if reservedNames.MatchString(name) {
+		return name, nil
+	}
+	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 "", errors.New("invalid utf-8")
+			}
+			u := make([]byte, len)
+			utf8.EncodeRune(u, s)
+			for _, r := range u {
+				hex := hex.EncodeToString([]byte{r})
+				encodedName = encodedName + "%" + strings.ToUpper(hex)
+			}
+		}
+	}
+	return encodedName, nil
+}
+
+// newSignV4Request - populate a new signature v4 request
+func newSignV4Request(user *auth.User, req *http.Request, body io.Reader) (*request, error) {
+	// save for subsequent use
+	r := new(request)
+	r.user = user
+	r.body = body
+	r.receivedReq = req
+	r.calculatedReq = req
+	return r, nil
+}
+
+// getHashedPayload get the hexadecimal value of the SHA256 hash of the request payload
+func (r *request) getHashedPayload() string {
+	hash := func() string {
+		switch {
+		case r.body == nil:
+			return hex.EncodeToString(sha256.Sum256([]byte{}))
+		default:
+			sum256Bytes, _ := sha256.Sum(r.body)
+			return hex.EncodeToString(sum256Bytes)
+		}
+	}
+	hashedPayload := hash()
+	r.calculatedReq.Header.Set("X-Amz-Content-Sha256", hashedPayload)
+	return hashedPayload
+}
+
+// getCanonicalHeaders generate a list of request headers with their values
+func (r *request) getCanonicalHeaders() string {
+	var headers []string
+	vals := make(map[string][]string)
+	for k, vv := range r.calculatedReq.Header {
+		if _, ok := ignoredHeaders[http.CanonicalHeaderKey(k)]; ok {
+			continue // ignored header
+		}
+		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.calculatedReq.URL.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 *request) getSignedHeaders() string {
+	var headers []string
+	for k := range r.calculatedReq.Header {
+		if _, ok := ignoredHeaders[http.CanonicalHeaderKey(k)]; ok {
+			continue // ignored header
+		}
+		headers = append(headers, strings.ToLower(k))
+	}
+	headers = append(headers, "host")
+	sort.Strings(headers)
+	return strings.Join(headers, ";")
+}
+
+// getCanonicalRequest generate a canonical request of style
+//
+// canonicalRequest =
+//  <HTTPMethod>\n
+//  <CanonicalURI>\n
+//  <CanonicalQueryString>\n
+//  <CanonicalHeaders>\n
+//  <SignedHeaders>\n
+//  <HashedPayload>
+//
+func (r *request) getCanonicalRequest(hashedPayload string) string {
+	r.calculatedReq.URL.RawQuery = strings.Replace(r.calculatedReq.URL.Query().Encode(), "+", "%20", -1)
+	encodedPath, _ := urlEncodeName(r.calculatedReq.URL.Path)
+	// convert any space strings back to "+"
+	encodedPath = strings.Replace(encodedPath, "+", "%20", -1)
+	canonicalRequest := strings.Join([]string{
+		r.calculatedReq.Method,
+		encodedPath,
+		r.calculatedReq.URL.RawQuery,
+		r.getCanonicalHeaders(),
+		r.getSignedHeaders(),
+		hashedPayload,
+	}, "\n")
+	return canonicalRequest
+}
+
+// getScope generate a string of a specific date, an AWS region, and a service
+func (r *request) 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 *request) getStringToSign(canonicalRequest string, t time.Time) string {
+	stringToSign := authHeader + "\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 *request) getSigningKey(t time.Time) []byte {
+	secret := r.user.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 *request) getSignature(signingKey []byte, stringToSign string) string {
+	return hex.EncodeToString(sumHMAC(signingKey, []byte(stringToSign)))
+}
+
+// SignV4 the request before Do(), in accordance with - http://docs.aws.amazon.com/AmazonS3/latest/API/sig-v4-authenticating-requests.html
+func (r *request) SignV4() (string, error) {
+	// Add date if not present
+	var date string
+	if date = r.calculatedReq.Header.Get("Date"); date == "" {
+		if date = r.calculatedReq.Header.Get("X-Amz-Date"); date == "" {
+			return "", iodine.New(MissingDateHeader{}, nil)
+		}
+	}
+	t, err := time.Parse(iso8601Format, date)
+	if err != nil {
+		return "", iodine.New(err, nil)
+	}
+	hashedPayload := r.getHashedPayload()
+	signedHeaders := r.getSignedHeaders()
+	canonicalRequest := r.getCanonicalRequest(hashedPayload)
+	scope := r.getScope(t)
+	stringToSign := r.getStringToSign(canonicalRequest, t)
+	signingKey := r.getSigningKey(t)
+	signature := r.getSignature(signingKey, stringToSign)
+
+	// final Authorization header
+	parts := []string{
+		authHeader + " Credential=" + r.user.AccessKeyID + "/" + scope,
+		"SignedHeaders=" + signedHeaders,
+		"Signature=" + signature,
+	}
+	auth := strings.Join(parts, ", ")
+	return auth, nil
+}