-
Notifications
You must be signed in to change notification settings - Fork 17
/
ssl.go
197 lines (179 loc) · 6.38 KB
/
ssl.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
package nzgo
import (
"crypto/tls"
"crypto/x509"
"io/ioutil"
"net"
"os"
"os/user"
"path/filepath"
)
const (
TLS1_CK_ECDHE_RSA_WITH_AES_256_GCM_SHA384 = 0xc030
TLS1_CK_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 = 0xc02c
TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 = 0xc02b
TLS1_CK_RSA_WITH_AES_128_GCM_SHA256 = 0x009c
TLS1_CK_RSA_WITH_AES_256_GCM_SHA384 = 0x009d
TLS1_CK_RSA_WITH_AES_128_SHA256 = 0x03c
TLS1_CK_ECDHE_ECDSA_WITH_AES_128_SHA256 = 0xc023
TLS1_CK_ECDHE_RSA_WITH_AES_128_SHA256 = 0xc027
)
// ssl generates a function to upgrade a net.Conn based on the "sslmode" and
// related settings. The function is nil when no upgrade should take place.
func ssl(o values) (func(net.Conn) (net.Conn, error), error) {
verifyCaOnly := false
tlsConf := tls.Config{}
tlsConf.MinVersion = tls.VersionTLS12
tlsConf.CipherSuites = []uint16{
TLS1_CK_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
TLS1_CK_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
TLS1_CK_RSA_WITH_AES_128_GCM_SHA256,
TLS1_CK_RSA_WITH_AES_256_GCM_SHA384,
TLS1_CK_RSA_WITH_AES_128_SHA256,
TLS1_CK_ECDHE_ECDSA_WITH_AES_128_SHA256,
TLS1_CK_ECDHE_RSA_WITH_AES_128_SHA256,
}
switch mode := o["sslmode"]; mode {
// "require" is the default.
case "", "require":
// We must skip TLS's own verification since it requires full
// verification since Go 1.3.
tlsConf.InsecureSkipVerify = true
// From http://www.postgresql.org/docs/current/static/libpq-ssl.html:
//
// Note: For backwards compatibility with earlier versions of
// PostgreSQL, if a root CA file exists, the behavior of
// sslmode=require will be the same as that of verify-ca, meaning the
// server certificate is validated against the CA. Relying on this
// behavior is discouraged, and applications that need certificate
// validation should always use verify-ca or verify-full.
if sslrootcert, ok := o["sslrootcert"]; ok {
if _, err := os.Stat(sslrootcert); err == nil {
verifyCaOnly = true
} else {
delete(o, "sslrootcert")
}
}
case "verify-ca":
// We must skip TLS's own verification since it requires full
// verification since Go 1.3.
tlsConf.InsecureSkipVerify = true
verifyCaOnly = true
case "verify-full":
tlsConf.ServerName = o["host"]
case "disable":
return nil, nil
default:
return nil, fmterrorf(`unsupported sslmode %q; only "require" (default), "verify-full", "verify-ca", and "disable" supported`, mode)
}
err := sslClientCertificates(&tlsConf, o)
if err != nil {
return nil, err
}
err = sslCertificateAuthority(&tlsConf, o)
if err != nil {
return nil, err
}
// Accept renegotiation requests initiated by the backend.
//
// Renegotiation was deprecated then removed from PostgreSQL 9.5, but
// the default configuration of older versions has it enabled. Redshift
// also initiates renegotiations and cannot be reconfigured.
tlsConf.Renegotiation = tls.RenegotiateFreelyAsClient
return func(conn net.Conn) (net.Conn, error) {
client := tls.Client(conn, &tlsConf)
if verifyCaOnly {
err := sslVerifyCertificateAuthority(client, &tlsConf)
if err != nil {
return nil, err
}
}
return client, nil
}, nil
}
// sslClientCertificates adds the certificate specified in the "sslcert" and
// "sslkey" settings, or if they aren't set, from the .postgresql directory
// in the user's home directory. The configured files must exist and have
// the correct permissions.
func sslClientCertificates(tlsConf *tls.Config, o values) error {
// user.Current() might fail when cross-compiling. We have to ignore the
// error and continue without home directory defaults, since we wouldn't
// know from where to load them.
user, _ := user.Current()
// In libpq, the client certificate is only loaded if the setting is not blank.
//
// https://github.com/postgres/postgres/blob/REL9_6_2/src/interfaces/libpq/fe-secure-openssl.c#L1036-L1037
sslcert := o["sslcert"]
if len(sslcert) == 0 && user != nil {
sslcert = filepath.Join(user.HomeDir, ".postgresql", "postgresql.crt")
}
// https://github.com/postgres/postgres/blob/REL9_6_2/src/interfaces/libpq/fe-secure-openssl.c#L1045
if len(sslcert) == 0 {
return nil
}
// https://github.com/postgres/postgres/blob/REL9_6_2/src/interfaces/libpq/fe-secure-openssl.c#L1050:L1054
if _, err := os.Stat(sslcert); os.IsNotExist(err) {
return nil
} else if err != nil {
return err
}
// In libpq, the ssl key is only loaded if the setting is not blank.
//
// https://github.com/postgres/postgres/blob/REL9_6_2/src/interfaces/libpq/fe-secure-openssl.c#L1123-L1222
sslkey := o["sslkey"]
if len(sslkey) == 0 && user != nil {
sslkey = filepath.Join(user.HomeDir, ".postgresql", "postgresql.key")
}
if len(sslkey) > 0 {
if err := sslKeyPermissions(sslkey); err != nil {
return err
}
}
cert, err := tls.LoadX509KeyPair(sslcert, sslkey)
if err != nil {
return err
}
tlsConf.Certificates = []tls.Certificate{cert}
return nil
}
// sslCertificateAuthority adds the RootCA specified in the "sslrootcert" setting.
func sslCertificateAuthority(tlsConf *tls.Config, o values) error {
// In libpq, the root certificate is only loaded if the setting is not blank.
//
// https://github.com/postgres/postgres/blob/REL9_6_2/src/interfaces/libpq/fe-secure-openssl.c#L950-L951
if sslrootcert := o["sslrootcert"]; len(sslrootcert) > 0 {
tlsConf.RootCAs = x509.NewCertPool()
cert, err := ioutil.ReadFile(sslrootcert)
if err != nil {
return err
}
if !tlsConf.RootCAs.AppendCertsFromPEM(cert) {
return fmterrorf("couldn't parse pem in sslrootcert")
}
}
return nil
}
// sslVerifyCertificateAuthority carries out a TLS handshake to the server and
// verifies the presented certificate against the CA, i.e. the one specified in
// sslrootcert or the system CA if sslrootcert was not specified.
func sslVerifyCertificateAuthority(client *tls.Conn, tlsConf *tls.Config) error {
err := client.Handshake()
if err != nil {
return err
}
certs := client.ConnectionState().PeerCertificates
opts := x509.VerifyOptions{
DNSName: client.ConnectionState().ServerName,
Intermediates: x509.NewCertPool(),
Roots: tlsConf.RootCAs,
}
for i, cert := range certs {
if i == 0 {
continue
}
opts.Intermediates.AddCert(cert)
}
_, err = certs[0].Verify(opts)
return err
}