diff options
Diffstat (limited to 'vendor/github.com/minio/minio-go/pkg/s3signer/request-signature-v4.go')
| -rw-r--r-- | vendor/github.com/minio/minio-go/pkg/s3signer/request-signature-v4.go | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/vendor/github.com/minio/minio-go/pkg/s3signer/request-signature-v4.go b/vendor/github.com/minio/minio-go/pkg/s3signer/request-signature-v4.go new file mode 100644 index 000000000..3322b67cc --- /dev/null +++ b/vendor/github.com/minio/minio-go/pkg/s3signer/request-signature-v4.go @@ -0,0 +1,305 @@ +/* + * Minio Go Library for Amazon S3 Compatible 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 s3signer + +import ( + "bytes" + "encoding/hex" + "net/http" + "sort" + "strconv" + "strings" + "time" + + "github.com/minio/minio-go/pkg/s3utils" +) + +// Signature and API related constants. +const ( + signV4Algorithm = "AWS4-HMAC-SHA256" + iso8601DateFormat = "20060102T150405Z" + yyyymmdd = "20060102" +) + +/// +/// Excerpts from @lsegal - +/// https://github.com/aws/aws-sdk-js/issues/659#issuecomment-120477258. +/// +/// User-Agent: +/// +/// This is ignored from signing because signing this causes +/// problems with generating pre-signed URLs (that are executed +/// by other agents) or when customers pass requests through +/// proxies, which may modify the user-agent. +/// +/// Content-Length: +/// +/// This is ignored from signing because generating a pre-signed +/// URL should not provide a content-length constraint, +/// specifically when vending a S3 pre-signed PUT URL. The +/// corollary to this is that when sending regular requests +/// (non-pre-signed), the signature contains a checksum of the +/// body, which implicitly validates the payload length (since +/// changing the number of bytes would change the checksum) +/// and therefore this header is not valuable in the signature. +/// +/// Content-Type: +/// +/// Signing this header causes quite a number of problems in +/// browser environments, where browsers like to modify and +/// normalize the content-type header in different ways. There is +/// more information on this in https://goo.gl/2E9gyy. Avoiding +/// this field simplifies logic and reduces the possibility of +/// future bugs. +/// +/// Authorization: +/// +/// Is skipped for obvious reasons +/// +var ignoredHeaders = map[string]bool{ + "Authorization": true, + "Content-Type": true, + "Content-Length": true, + "User-Agent": true, +} + +// getSigningKey hmac seed to calculate final signature. +func getSigningKey(secret, loc string, t time.Time) []byte { + date := sumHMAC([]byte("AWS4"+secret), []byte(t.Format(yyyymmdd))) + location := sumHMAC(date, []byte(loc)) + service := sumHMAC(location, []byte("s3")) + signingKey := sumHMAC(service, []byte("aws4_request")) + return signingKey +} + +// getSignature final signature in hexadecimal form. +func getSignature(signingKey []byte, stringToSign string) string { + return hex.EncodeToString(sumHMAC(signingKey, []byte(stringToSign))) +} + +// getScope generate a string of a specific date, an AWS region, and a +// service. +func getScope(location string, t time.Time) string { + scope := strings.Join([]string{ + t.Format(yyyymmdd), + location, + "s3", + "aws4_request", + }, "/") + return scope +} + +// GetCredential generate a credential string. +func GetCredential(accessKeyID, location string, t time.Time) string { + scope := getScope(location, t) + return accessKeyID + "/" + scope +} + +// getHashedPayload get the hexadecimal value of the SHA256 hash of +// the request payload. +func getHashedPayload(req http.Request) string { + hashedPayload := req.Header.Get("X-Amz-Content-Sha256") + if hashedPayload == "" { + // Presign does not have a payload, use S3 recommended value. + hashedPayload = unsignedPayload + } + return hashedPayload +} + +// getCanonicalHeaders generate a list of request headers for +// signature. +func getCanonicalHeaders(req http.Request) string { + var headers []string + vals := make(map[string][]string) + for k, vv := range req.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 + // Save all the headers in canonical form <header>:<value> newline + // separated for each header. + for _, k := range headers { + buf.WriteString(k) + buf.WriteByte(':') + switch { + case k == "host": + buf.WriteString(req.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 all signed request headers. +// i.e lexically sorted, semicolon-separated list of lowercase +// request header names. +func getSignedHeaders(req http.Request) string { + var headers []string + for k := range req.Header { + if _, ok := ignoredHeaders[http.CanonicalHeaderKey(k)]; ok { + continue // Ignored header found continue. + } + 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 getCanonicalRequest(req http.Request) string { + req.URL.RawQuery = strings.Replace(req.URL.Query().Encode(), "+", "%20", -1) + canonicalRequest := strings.Join([]string{ + req.Method, + s3utils.EncodePath(req.URL.Path), + req.URL.RawQuery, + getCanonicalHeaders(req), + getSignedHeaders(req), + getHashedPayload(req), + }, "\n") + return canonicalRequest +} + +// getStringToSign a string based on selected query values. +func getStringToSignV4(t time.Time, location, canonicalRequest string) string { + stringToSign := signV4Algorithm + "\n" + t.Format(iso8601DateFormat) + "\n" + stringToSign = stringToSign + getScope(location, t) + "\n" + stringToSign = stringToSign + hex.EncodeToString(sum256([]byte(canonicalRequest))) + return stringToSign +} + +// PreSignV4 presign the request, in accordance with +// http://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-query-string-auth.html. +func PreSignV4(req http.Request, accessKeyID, secretAccessKey, location string, expires int64) *http.Request { + // Presign is not needed for anonymous credentials. + if accessKeyID == "" || secretAccessKey == "" { + return &req + } + + // Initial time. + t := time.Now().UTC() + + // Get credential string. + credential := GetCredential(accessKeyID, location, t) + + // Get all signed headers. + signedHeaders := getSignedHeaders(req) + + // Set URL query. + query := req.URL.Query() + query.Set("X-Amz-Algorithm", signV4Algorithm) + query.Set("X-Amz-Date", t.Format(iso8601DateFormat)) + query.Set("X-Amz-Expires", strconv.FormatInt(expires, 10)) + query.Set("X-Amz-SignedHeaders", signedHeaders) + query.Set("X-Amz-Credential", credential) + req.URL.RawQuery = query.Encode() + + // Get canonical request. + canonicalRequest := getCanonicalRequest(req) + + // Get string to sign from canonical request. + stringToSign := getStringToSignV4(t, location, canonicalRequest) + + // Gext hmac signing key. + signingKey := getSigningKey(secretAccessKey, location, t) + + // Calculate signature. + signature := getSignature(signingKey, stringToSign) + + // Add signature header to RawQuery. + req.URL.RawQuery += "&X-Amz-Signature=" + signature + + return &req +} + +// PostPresignSignatureV4 - presigned signature for PostPolicy +// requests. +func PostPresignSignatureV4(policyBase64 string, t time.Time, secretAccessKey, location string) string { + // Get signining key. + signingkey := getSigningKey(secretAccessKey, location, t) + // Calculate signature. + signature := getSignature(signingkey, policyBase64) + return signature +} + +// SignV4 sign the request before Do(), in accordance with +// http://docs.aws.amazon.com/AmazonS3/latest/API/sig-v4-authenticating-requests.html. +func SignV4(req http.Request, accessKeyID, secretAccessKey, location string) *http.Request { + // Signature calculation is not needed for anonymous credentials. + if accessKeyID == "" || secretAccessKey == "" { + return &req + } + + // Initial time. + t := time.Now().UTC() + + // Set x-amz-date. + req.Header.Set("X-Amz-Date", t.Format(iso8601DateFormat)) + + // Get canonical request. + canonicalRequest := getCanonicalRequest(req) + + // Get string to sign from canonical request. + stringToSign := getStringToSignV4(t, location, canonicalRequest) + + // Get hmac signing key. + signingKey := getSigningKey(secretAccessKey, location, t) + + // Get credential string. + credential := GetCredential(accessKeyID, location, t) + + // Get all signed headers. + signedHeaders := getSignedHeaders(req) + + // Calculate signature. + signature := getSignature(signingKey, stringToSign) + + // If regular request, construct the final authorization header. + parts := []string{ + signV4Algorithm + " Credential=" + credential, + "SignedHeaders=" + signedHeaders, + "Signature=" + signature, + } + + // Set authorization header. + auth := strings.Join(parts, ", ") + req.Header.Set("Authorization", auth) + + return &req +} |