forked from containers/image
/
wwwauthenticate.go
159 lines (145 loc) · 3.71 KB
/
wwwauthenticate.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
package docker
// Based on github.com/docker/distribution/registry/client/auth/authchallenge.go, primarily stripping unnecessary dependencies.
import (
"net/http"
"strings"
)
// challenge carries information from a WWW-Authenticate response header.
// See RFC 7235.
type challenge struct {
// Scheme is the auth-scheme according to RFC 7235
Scheme string
// Parameters are the auth-params according to RFC 7235
Parameters map[string]string
}
// Octet types from RFC 7230.
type octetType byte
var octetTypes [256]octetType
const (
isToken octetType = 1 << iota
isSpace
)
func init() {
// OCTET = <any 8-bit sequence of data>
// CHAR = <any US-ASCII character (octets 0 - 127)>
// CTL = <any US-ASCII control character (octets 0 - 31) and DEL (127)>
// CR = <US-ASCII CR, carriage return (13)>
// LF = <US-ASCII LF, linefeed (10)>
// SP = <US-ASCII SP, space (32)>
// HT = <US-ASCII HT, horizontal-tab (9)>
// <"> = <US-ASCII double-quote mark (34)>
// CRLF = CR LF
// LWS = [CRLF] 1*( SP | HT )
// TEXT = <any OCTET except CTLs, but including LWS>
// separators = "(" | ")" | "<" | ">" | "@" | "," | ";" | ":" | "\" | <">
// | "/" | "[" | "]" | "?" | "=" | "{" | "}" | SP | HT
// token = 1*<any CHAR except CTLs or separators>
// qdtext = <any TEXT except <">>
for c := 0; c < 256; c++ {
var t octetType
isCtl := c <= 31 || c == 127
isChar := 0 <= c && c <= 127
isSeparator := strings.IndexRune(" \t\"(),/:;<=>?@[]\\{}", rune(c)) >= 0
if strings.IndexRune(" \t\r\n", rune(c)) >= 0 {
t |= isSpace
}
if isChar && !isCtl && !isSeparator {
t |= isToken
}
octetTypes[c] = t
}
}
func parseAuthHeader(header http.Header) []challenge {
challenges := []challenge{}
for _, h := range header[http.CanonicalHeaderKey("WWW-Authenticate")] {
v, p := parseValueAndParams(h)
if v != "" {
challenges = append(challenges, challenge{Scheme: v, Parameters: p})
}
}
return challenges
}
// NOTE: This is not a fully compliant parser per RFC 7235:
// Most notably it does not support more than one challenge within a single header
// Some of the whitespace parsing also seems noncompliant.
// But it is clearly better than what we used to have…
func parseValueAndParams(header string) (value string, params map[string]string) {
params = make(map[string]string)
value, s := expectToken(header)
if value == "" {
return
}
value = strings.ToLower(value)
s = "," + skipSpace(s)
for strings.HasPrefix(s, ",") {
var pkey string
pkey, s = expectToken(skipSpace(s[1:]))
if pkey == "" {
return
}
if !strings.HasPrefix(s, "=") {
return
}
var pvalue string
pvalue, s = expectTokenOrQuoted(s[1:])
if pvalue == "" {
return
}
pkey = strings.ToLower(pkey)
params[pkey] = pvalue
s = skipSpace(s)
}
return
}
func skipSpace(s string) (rest string) {
i := 0
for ; i < len(s); i++ {
if octetTypes[s[i]]&isSpace == 0 {
break
}
}
return s[i:]
}
func expectToken(s string) (token, rest string) {
i := 0
for ; i < len(s); i++ {
if octetTypes[s[i]]&isToken == 0 {
break
}
}
return s[:i], s[i:]
}
func expectTokenOrQuoted(s string) (value string, rest string) {
if !strings.HasPrefix(s, "\"") {
return expectToken(s)
}
s = s[1:]
for i := 0; i < len(s); i++ {
switch s[i] {
case '"':
return s[:i], s[i+1:]
case '\\':
p := make([]byte, len(s)-1)
j := copy(p, s[:i])
escape := true
for i = i + 1; i < len(s); i++ {
b := s[i]
switch {
case escape:
escape = false
p[j] = b
j++
case b == '\\':
escape = true
case b == '"':
return string(p[:j]), s[i+1:]
default:
p[j] = b
j++
}
}
return "", ""
}
}
return "", ""
}