/
signature.go
184 lines (150 loc) · 4.68 KB
/
signature.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
package gorpmapper
import (
"bytes"
"context"
"crypto/sha1"
"fmt"
"text/template"
"github.com/go-gorp/gorp"
"github.com/ovh/symmecrypt"
"github.com/rockbears/log"
"github.com/ovh/cds/sdk"
)
// Constant for gorp mapping.
const (
KeySignIdentifier = "db-sign"
)
type Signed interface {
GetSignature() []byte
}
// Canonicaller returns a byte array that represent its data.
type Canonicaller interface {
Canonical() CanonicalForms
}
// InsertAndSign a data in database, given data should implement canonicaller interface.
func (m *Mapper) InsertAndSign(ctx context.Context, db gorp.SqlExecutor, i Canonicaller) error {
if err := m.Insert(db, i); err != nil {
return err
}
return sdk.WithStack(m.dbSign(ctx, db, i))
}
// UpdateAndSign a data in database, given data should implement canonicaller interface.
func (m *Mapper) UpdateAndSign(ctx context.Context, db gorp.SqlExecutor, i Canonicaller) error {
if err := m.Update(db, i); err != nil {
return err
}
return sdk.WithStack(m.dbSign(ctx, db, i))
}
// UpdateColumnsAndSign a data in database, given data should implement canonicaller interface.
func (m *Mapper) UpdateColumnsAndSign(ctx context.Context, db gorp.SqlExecutor, i Canonicaller, colFilter gorp.ColumnFilter) error {
if err := m.UpdateColumns(db, i, colFilter); err != nil {
return err
}
return sdk.WithStack(m.dbSign(ctx, db, i))
}
// CheckSignature return true if a given signature is valid for given object.
func (m *Mapper) CheckSignature(i Canonicaller, sig []byte) (bool, error) {
var canonicalForms = i.Canonical()
var f *CanonicalForm
for {
f, canonicalForms = canonicalForms.Latest()
if f == nil {
return false, nil
}
ok, err := m.checkSignature(i, m.signatureKey, f, sig)
if err != nil {
return ok, err
}
if ok {
return true, nil
}
}
}
func (m *Mapper) checkSignature(i Canonicaller, k symmecrypt.Key, f *CanonicalForm, sig []byte) (bool, error) {
tmpl, err := m.getCanonicalTemplate(f)
if err != nil {
return false, err
}
var clearContent = new(bytes.Buffer)
if err := tmpl.Execute(clearContent, i); err != nil {
return false, nil
}
decryptedSig, err := k.Decrypt(sig)
if err != nil {
return false, sdk.WrapError(err, "unable to decrypt content (%s)", string(sig))
}
clearContentStr := clearContent.String()
res := clearContentStr == string(decryptedSig)
return res, nil
}
func (m *Mapper) getCanonicalTemplate(f *CanonicalForm) (*template.Template, error) {
sha := getSigner(f)
m.CanonicalFormTemplates.L.RLock()
t, has := m.CanonicalFormTemplates.M[sha]
m.CanonicalFormTemplates.L.RUnlock()
if !has {
return nil, sdk.WithStack(fmt.Errorf("no canonical function available"))
}
return t, nil
}
func getSigner(f *CanonicalForm) string {
h := sha1.New()
_, _ = h.Write(f.Bytes())
bs := h.Sum(nil)
sha := fmt.Sprintf("%x", bs)
return sha
}
func (m *Mapper) canonicalTemplate(data Canonicaller) (string, *template.Template, error) {
f, _ := data.Canonical().Latest()
if f == nil {
return "", nil, sdk.WithStack(fmt.Errorf("no canonical function available for %T", data))
}
sha := getSigner(f)
m.CanonicalFormTemplates.L.RLock()
t, has := m.CanonicalFormTemplates.M[sha]
m.CanonicalFormTemplates.L.RUnlock()
if !has {
return "", nil, sdk.WithStack(fmt.Errorf("no canonical function available for %T", data))
}
return sha, t, nil
}
func (m *Mapper) sign(data Canonicaller) (string, []byte, error) {
signer, tmpl, err := m.canonicalTemplate(data)
if err != nil {
return "", nil, err
}
if tmpl == nil {
err := fmt.Errorf("unable to get canonical form template for %T", data)
return "", nil, sdk.WrapError(err, "unable to sign data")
}
var clearContent = new(bytes.Buffer)
if err := tmpl.Execute(clearContent, data); err != nil {
return "", nil, sdk.WrapError(err, "unable to sign data")
}
btes, err := m.signatureKey.Encrypt(clearContent.Bytes())
if err != nil {
return "", nil, sdk.WithStack(fmt.Errorf("unable to encrypt content: %v", err))
}
return signer, btes, nil
}
func (m *Mapper) dbSign(ctx context.Context, db gorp.SqlExecutor, i Canonicaller) error {
signer, signature, err := m.sign(i)
if err != nil {
return err
}
table, key, id, err := m.dbMappingPKey(i)
if err != nil {
return sdk.WrapError(err, "primary key field not found in table: %s", table)
}
query := fmt.Sprintf(`UPDATE "%s" SET sig = $2, signer = $3 WHERE %s = $1`, table, key)
res, err := db.Exec(query, id, signature, signer)
if err != nil {
log.Error(ctx, "error executing query %s with parameters %s, %s: %v", query, table, key, err)
return sdk.WithStack(err)
}
n, _ := res.RowsAffected()
if n != 1 {
return sdk.WithStack(fmt.Errorf("%d number of rows affected (table=%s, key=%s, id=%v)", n, table, key, id))
}
return nil
}