forked from open-policy-agent/opa
/
providers.go
191 lines (163 loc) · 5 KB
/
providers.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
// Copyright 2022 The OPA Authors. All rights reserved.
// Use of this source code is governed by an Apache2
// license that can be found in the LICENSE file.
package topdown
import (
"encoding/json"
"net/url"
"time"
"github.com/open-policy-agent/opa/ast"
"github.com/open-policy-agent/opa/internal/providers"
"github.com/open-policy-agent/opa/topdown/builtins"
)
var awsRequiredConfigKeyNames = ast.NewSet(
ast.StringTerm("aws_service"),
ast.StringTerm("aws_access_key"),
ast.StringTerm("aws_secret_access_key"),
ast.StringTerm("aws_region"),
)
func stringFromTerm(t *ast.Term) string {
if v, ok := t.Value.(ast.String); ok {
return string(v)
}
return ""
}
func getReqBodyBytes(body, rawBody *ast.Term) ([]byte, error) {
var out []byte
switch {
case rawBody != nil:
out = []byte(stringFromTerm(rawBody))
case body != nil:
bodyVal := body.Value
bodyValInterface, err := ast.JSON(bodyVal)
if err != nil {
return nil, err
}
bodyValBytes, err := json.Marshal(bodyValInterface)
if err != nil {
return nil, err
}
out = bodyValBytes
default:
out = []byte("")
}
return out, nil
}
func objectToMap(o ast.Object) map[string][]string {
var out map[string][]string
o.Foreach(func(k, v *ast.Term) {
ks := stringFromTerm(k)
vs := stringFromTerm(v)
out[ks] = []string{vs}
})
return out
}
// Note(philipc): This is roughly the same approach used for http.send.
func validateAWSAuthParameters(o ast.Object) error {
awsKeys := ast.NewSet(o.Keys()...)
missingKeys := awsRequiredConfigKeyNames.Diff(awsKeys)
if missingKeys.Len() != 0 {
return builtins.NewOperandErr(2, "missing required AWS config parameters(s): %v", missingKeys)
}
invalidKeys := ast.NewSet()
awsRequiredConfigKeyNames.Foreach(func(t *ast.Term) {
if v := o.Get(t); v != nil {
if _, ok := v.Value.(ast.String); !ok {
invalidKeys.Add(t)
}
}
})
if invalidKeys.Len() != 0 {
return builtins.NewOperandErr(2, "invalid values for required AWS config parameters(s): %v", invalidKeys)
}
return nil
}
func builtinAWSSigV4SignReq(ctx BuiltinContext, operands []*ast.Term, iter func(*ast.Term) error) error {
// Request object.
reqObj, err := builtins.ObjectOperand(operands[0].Value, 1)
if err != nil {
return err
}
// AWS SigV4 config info object.
awsConfigObj, err := builtins.ObjectOperand(operands[1].Value, 1)
if err != nil {
return err
}
// Make sure our required keys exist!
err = validateAWSAuthParameters(awsConfigObj)
if err != nil {
return err
}
service := stringFromTerm(awsConfigObj.Get(ast.StringTerm("aws_service")))
awsCreds := providers.AWSCredentialsFromObject(awsConfigObj)
// Timestamp for signing.
var signingTimestamp time.Time
timestamp, err := builtins.NumberOperand(operands[2].Value, 1)
if err != nil {
return err
}
ts, ok := timestamp.Int64()
if !ok {
return builtins.NewOperandErr(3, "could not convert time_ns value into a unix timestamp")
}
signingTimestamp = time.Unix(0, ts)
if err != nil {
return err
}
// Make sure our required keys exist!
// This check is stricter than required, but better to break here than downstream.
_, err = validateHTTPRequestOperand(operands[0], 1)
if err != nil {
return err
}
// Prepare required fields from the HTTP request object.
var theURL *url.URL
var method string
reqURL := reqObj.Get(ast.StringTerm("url"))
reqMethod := reqObj.Get(ast.StringTerm("method"))
headers := ast.NewObject()
headersTerm := reqObj.Get(ast.StringTerm("headers"))
if headersTerm != nil {
var ok bool
headers, ok = headersTerm.Value.(ast.Object)
if !ok {
return builtins.NewOperandTypeErr(0, headersTerm.Value, "object")
}
}
// Check types on the request parameters.
invalidParameters := ast.NewSet()
if _, ok := reqURL.Value.(ast.String); !ok {
invalidParameters.Add(ast.StringTerm("url"))
}
if _, ok := reqMethod.Value.(ast.String); !ok {
invalidParameters.Add(ast.StringTerm("method"))
}
if invalidParameters.Len() > 0 {
return builtins.NewOperandErr(1, "invalid values for required request parameters(s): %v", invalidParameters)
}
theURL, err = url.Parse(stringFromTerm(reqURL))
if err != nil {
return err
}
method = stringFromTerm(reqMethod)
bodyTerm := reqObj.Get(ast.StringTerm("body"))
rawBodyTerm := reqObj.Get(ast.StringTerm("raw_body"))
body, err := getReqBodyBytes(bodyTerm, rawBodyTerm)
if err != nil {
return err
}
// Sign the request object's headers, and reconstruct the headers map.
authHeader, signedHeadersMap := providers.AWSSignV4(objectToMap(headers), method, theURL, body, service, awsCreds, signingTimestamp)
signedHeadersObj := ast.NewObject()
signedHeadersObj.Insert(ast.StringTerm("Authorization"), ast.StringTerm(authHeader))
for k, v := range signedHeadersMap {
signedHeadersObj.Insert(ast.StringTerm(k), ast.StringTerm(v))
}
// Create new request object with updated headers.
out := reqObj.Copy()
out.Insert(ast.StringTerm("headers"), ast.NewTerm(signedHeadersObj))
return iter(ast.NewTerm(out))
}
func init() {
RegisterBuiltinFunc(ast.ProvidersAWSSignReqObj.Name, builtinAWSSigV4SignReq)
}