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/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package auth
import (
"net/http"
"sort"
"strings"
)
// AuthenticationScheme defines scheme of the authentication method
type AuthenticationScheme byte
const (
// BasicAuth is scheme for Basic HTTP Authentication RFC 7617
BasicAuth AuthenticationScheme = 1 << iota
// DigestAuth is scheme for HTTP Digest Access Authentication RFC 7616
DigestAuth
// BearerAuth is scheme for OAuth 2.0 Bearer Tokens RFC 6750
BearerAuth
)
// Challenge carries information from a WWW-Authenticate response header.
// See RFC 2617.
type Challenge struct {
// scheme is the auth-scheme according to RFC 2617
Scheme AuthenticationScheme
// parameters are the auth-params according to RFC 2617
Parameters map[string]string
}
type byScheme []Challenge
func (bs byScheme) Len() int { return len(bs) }
func (bs byScheme) Swap(i, j int) { bs[i], bs[j] = bs[j], bs[i] }
// Less sorts in priority order: token > digest > basic
func (bs byScheme) Less(i, j int) bool { return bs[i].Scheme > bs[j].Scheme }
// Octet types from RFC 2616.
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.ContainsRune(" \t\"(),/:;<=>?@[]\\{}", rune(c))
if strings.ContainsRune(" \t\r\n", rune(c)) {
t |= isSpace
}
if isChar && !isCtl && !isSeparator {
t |= isToken
}
octetTypes[c] = t
}
}
// ParseAuthHeader parses challenges from WWW-Authenticate header
func ParseAuthHeader(header http.Header) []Challenge {
challenges := []Challenge{}
for _, h := range header[http.CanonicalHeaderKey("WWW-Authenticate")] {
v, p := parseValueAndParams(h)
var s AuthenticationScheme
switch v {
case "basic":
s = BasicAuth
case "digest":
s = DigestAuth
case "bearer":
s = BearerAuth
default:
continue
}
challenges = append(challenges, Challenge{Scheme: s, Parameters: p})
}
sort.Stable(byScheme(challenges))
return challenges
}
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)
for {
var pkey string
pkey, s = expectToken(skipSpace(s))
if pkey == "" {
return
}
if !strings.HasPrefix(s, "=") {
return
}
var pvalue string
pvalue, s = expectTokenOrQuoted(s[1:])
pkey = strings.ToLower(pkey)
params[pkey] = pvalue
s = skipSpace(s)
if !strings.HasPrefix(s, ",") {
return
}
s = s[1:]
}
}
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 "", ""
}
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