forked from smugmug/godynamo
/
auth_v4.go
218 lines (194 loc) · 7.37 KB
/
auth_v4.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
// Copyright (c) 2013,2014 SmugMug, Inc. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY SMUGMUG, INC. ``AS IS'' AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SMUGMUG, INC. BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
// GOODS OR SERVICES;LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
// IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
// OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Manages AWS Auth v4 requests to DynamoDB.
// See http://docs.aws.amazon.com/general/latest/gr/signature-version-4.html
// for more information on v4 signed requests. For examples, see any of
// the package in the `endpoints` directory.
package auth_v4
import (
"net/http"
"fmt"
"strconv"
"errors"
"io"
"io/ioutil"
"strings"
"hash"
"time"
"crypto/sha256"
"hash/crc32"
"encoding/hex"
"github.com/smugmug/godynamo/auth_v4/tasks"
"github.com/smugmug/godynamo/aws_const"
"github.com/smugmug/godynamo/conf"
)
const (
IAM_WARN_MESSAGE = "check roles sources and make sure you have run one of the roles " +
"management functions in package conf_iam, such as GoIAM"
)
// Client for executing requests.
var Client *http.Client
// Initialize package-scoped client.
func init() {
tr := &http.Transport{ResponseHeaderTimeout: time.Duration(20) * time.Second}
Client = &http.Client{Transport:tr}
}
// GetRespReqID retrieves the unique identifier from the AWS Response
func GetRespReqID(response http.Response) (string,error) {
if amz_reqid_list,reqid_ok := response.Header["X-Amzn-Requestid"]; reqid_ok {
if len(amz_reqid_list) == 1 {
return amz_reqid_list[0],nil
}
}
return "",errors.New("auth_v4.GetRespReqID: no X-Amzn-Requestid found")
}
// MatchCheckSum will perform a local crc32 on the response body and match it against the aws crc32
// *** WARNING ***
// There seems to be a mismatch between what Go calculates and what AWS (java?) calculates here,
// I believe related to utf8 (go) vs utf16 (java), but I don't know enough about encodings to
// solve it. So until that issue is solved, don't use this.
func MatchCheckSum(response http.Response,respbody []byte) (bool,error) {
if amz_crc_list,crc_ok := response.Header["X-Amz-Crc32"]; crc_ok {
if len(amz_crc_list) == 1 {
amz_crc_int32,amz_crc32_err := strconv.Atoi(amz_crc_list[0])
if amz_crc32_err == nil {
client_crc_int32 := int(crc32.ChecksumIEEE(respbody))
if amz_crc_int32 != client_crc_int32 {
_ = fmt.Sprintf("auth_v4.RawReq: resp crc mismatch: amz %d client %d",
amz_crc_int32,client_crc_int32)
return false,nil
}
}
} else {
return false,errors.New("auth_v4.MatchCheckSum: X-Amz-Crc32 malformed")
}
} else {
return false,errors.New("auth_v4.MatchCheckSum: no X-Amz-Crc32 found")
}
return true,nil
}
// RawReq will sign and transmit the request to the AWS DynanoDB endpoint.
// This method is DynamoDB-specific.
func RawReq(reqJSON []byte,amzTarget string) (string,string,int,error) {
// shadow conf vars in a read lock to minimize contention
conf.Vals.ConfLock.RLock()
conf_url_str := conf.Vals.Network.DynamoDB.URL
conf_host := conf.Vals.Network.DynamoDB.Host
conf_port_str := conf.Vals.Network.DynamoDB.Port
conf_zone := conf.Vals.Network.DynamoDB.Zone
conf_useIAM := conf.Vals.UseIAM
conf_IAMSecret := conf.Vals.IAM.Credentials.Secret
conf_IAMAccessKey := conf.Vals.IAM.Credentials.AccessKey
conf_IAMToken := conf.Vals.IAM.Credentials.Token
conf_AuthSecret := conf.Vals.Auth.Secret
conf_AuthAccessKey := conf.Vals.Auth.AccessKey
conf.Vals.ConfLock.RUnlock()
// initialize req with body reader
body := strings.NewReader(string(reqJSON))
request,req_err := http.NewRequest(aws_const.METHOD,conf_url_str,body)
if req_err != nil {
e := fmt.Sprintf("auth_v4.RawReq:failed init conn %s",req_err.Error())
return "","",0,errors.New(e)
}
// add headers
// content type
request.Header.Add(aws_const.CONTENT_TYPE_HDR,aws_const.CTYPE)
// amz target
request.Header.Add(aws_const.AMZ_TARGET_HDR,amzTarget)
// dates
now := time.Now()
request.Header.Add(aws_const.X_AMZ_DATE_HDR,
now.UTC().Format(aws_const.ISO8601FMT_CONDENSED))
// encode request json payload
var h256 hash.Hash = sha256.New()
h256.Write(reqJSON)
hexPayload := string(hex.EncodeToString([]byte(h256.Sum(nil))))
// create the various signed formats aws uses for v4 signed reqs
service := strings.ToLower(aws_const.DYNAMODB)
canonical_request := tasks.CanonicalRequest(
conf_host,
conf_port_str,
request.Header.Get(aws_const.X_AMZ_DATE_HDR),
request.Header.Get(aws_const.AMZ_TARGET_HDR),
hexPayload)
str2sign := tasks.String2Sign(now,canonical_request,
conf_zone,
service)
// obtain the aws secret credential from the global Auth or from IAM
var secret string
if conf_useIAM == true {
secret = conf_IAMSecret
} else {
secret = conf_AuthSecret
}
if secret == "" {
panic("auth_v4.cacheable_hmacs: no Secret defined; " + IAM_WARN_MESSAGE)
}
signature := tasks.MakeSignature(str2sign,conf_zone,service,secret)
// obtain the aws accessKey credential from the global Auth or from IAM
// if using IAM, read the token while we have the lock
var accessKey,token string
if conf_useIAM == true {
accessKey = conf_IAMAccessKey
token = conf_IAMToken
} else {
accessKey = conf_AuthAccessKey
}
if accessKey == "" {
panic("auth_v4.RawReq: no Access Key defined; " + IAM_WARN_MESSAGE)
}
v4auth := "AWS4-HMAC-SHA256 Credential=" + accessKey +
"/" + now.UTC().Format(aws_const.ISODATEFMT) + "/" +
conf_zone + "/" + service + "/aws4_request," +
"SignedHeaders=content-type;host;x-amz-date;x-amz-target," +
"Signature=" + signature
request.Header.Add("Authorization",v4auth)
if conf_useIAM == true {
if token == "" {
panic("auth_v4.RawReq: no Token defined;" + IAM_WARN_MESSAGE)
}
request.Header.Add(aws_const.X_AMZ_SECURITY_TOKEN_HDR,token)
}
// where we finally send req to aws
response,rsp_err := Client.Do(request)
if rsp_err != nil {
return "","",0,rsp_err
}
defer response.Body.Close()
respbody,read_err := ioutil.ReadAll(response.Body)
if read_err != nil && read_err != io.EOF {
e := fmt.Sprintf("auth_v4.RawReq:err reading resp body: %s",read_err.Error())
return "","",0,errors.New(e)
}
amz_requestid,amz_requestid_err := GetRespReqID(*response)
if amz_requestid_err != nil {
return "","",0,amz_requestid_err
}
return string(respbody),amz_requestid,response.StatusCode,nil
}
// Req is just a wrapper for RawReq if we need to massage data
// before dispatch.
func Req(reqJSON []byte,amzTarget string) (string,string,int,error) {
return RawReq(reqJSON,amzTarget)
}