distribution/registry/auth/htpasswd/htpasswd.go

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package htpasswd
import (
"bufio"
"fmt"
"io"
"strings"
"github.com/docker/distribution/registry/auth"
"golang.org/x/crypto/bcrypt"
)
// htpasswd holds a path to a system .htpasswd file and the machinery to parse
// it. Only bcrypt hash entries are supported.
type htpasswd struct {
entries map[string][]byte // maps username to password byte slice.
}
// newHTPasswd parses the reader and returns an htpasswd or an error.
func newHTPasswd(rd io.Reader) (*htpasswd, error) {
entries, err := parseHTPasswd(rd)
if err != nil {
return nil, err
}
return &htpasswd{entries: entries}, nil
}
// AuthenticateUser checks a given user:password credential against the
// receiving HTPasswd's file. If the check passes, nil is returned.
func (htpasswd *htpasswd) authenticateUser(username string, password string) error {
credentials, ok := htpasswd.entries[username]
if !ok {
// timing attack paranoia
bcrypt.CompareHashAndPassword([]byte{}, []byte(password))
return auth.ErrAuthenticationFailure
}
err := bcrypt.CompareHashAndPassword([]byte(credentials), []byte(password))
if err != nil {
return auth.ErrAuthenticationFailure
}
return nil
}
// parseHTPasswd parses the contents of htpasswd. This will read all the
// entries in the file, whether or not they are needed. An error is returned
// if a syntax errors are encountered or if the reader fails.
func parseHTPasswd(rd io.Reader) (map[string][]byte, error) {
entries := map[string][]byte{}
scanner := bufio.NewScanner(rd)
var line int
for scanner.Scan() {
line++ // 1-based line numbering
t := strings.TrimSpace(scanner.Text())
if len(t) < 1 {
continue
}
// lines that *begin* with a '#' are considered comments
if t[0] == '#' {
continue
}
i := strings.Index(t, ":")
if i < 0 || i >= len(t) {
return nil, fmt.Errorf("htpasswd: invalid entry at line %d: %q", line, scanner.Text())
}
entries[t[:i]] = []byte(t[i+1:])
}
if err := scanner.Err(); err != nil {
return nil, err
}
return entries, nil
}