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-rw-r--r--vendor/golang.org/x/crypto/ssh/knownhosts/knownhosts.go547
1 files changed, 547 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/knownhosts/knownhosts.go b/vendor/golang.org/x/crypto/ssh/knownhosts/knownhosts.go
new file mode 100644
index 000000000..d1f371868
--- /dev/null
+++ b/vendor/golang.org/x/crypto/ssh/knownhosts/knownhosts.go
@@ -0,0 +1,547 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package knownhosts implements a parser for the OpenSSH
+// known_hosts host key database.
+package knownhosts
+
+import (
+ "bufio"
+ "bytes"
+ "crypto/hmac"
+ "crypto/rand"
+ "crypto/sha1"
+ "encoding/base64"
+ "errors"
+ "fmt"
+ "io"
+ "net"
+ "os"
+ "strings"
+
+ "golang.org/x/crypto/ssh"
+)
+
+// See the sshd manpage
+// (http://man.openbsd.org/sshd#SSH_KNOWN_HOSTS_FILE_FORMAT) for
+// background.
+
+type addr struct{ host, port string }
+
+func (a *addr) String() string {
+ h := a.host
+ if strings.Contains(h, ":") {
+ h = "[" + h + "]"
+ }
+ return h + ":" + a.port
+}
+
+type matcher interface {
+ match([]addr) bool
+}
+
+type hostPattern struct {
+ negate bool
+ addr addr
+}
+
+func (p *hostPattern) String() string {
+ n := ""
+ if p.negate {
+ n = "!"
+ }
+
+ return n + p.addr.String()
+}
+
+type hostPatterns []hostPattern
+
+func (ps hostPatterns) match(addrs []addr) bool {
+ matched := false
+ for _, p := range ps {
+ for _, a := range addrs {
+ m := p.match(a)
+ if !m {
+ continue
+ }
+ if p.negate {
+ return false
+ }
+ matched = true
+ }
+ }
+ return matched
+}
+
+// See
+// https://android.googlesource.com/platform/external/openssh/+/ab28f5495c85297e7a597c1ba62e996416da7c7e/addrmatch.c
+// The matching of * has no regard for separators, unlike filesystem globs
+func wildcardMatch(pat []byte, str []byte) bool {
+ for {
+ if len(pat) == 0 {
+ return len(str) == 0
+ }
+ if len(str) == 0 {
+ return false
+ }
+
+ if pat[0] == '*' {
+ if len(pat) == 1 {
+ return true
+ }
+
+ for j := range str {
+ if wildcardMatch(pat[1:], str[j:]) {
+ return true
+ }
+ }
+ return false
+ }
+
+ if pat[0] == '?' || pat[0] == str[0] {
+ pat = pat[1:]
+ str = str[1:]
+ } else {
+ return false
+ }
+ }
+}
+
+func (l *hostPattern) match(a addr) bool {
+ return wildcardMatch([]byte(l.addr.host), []byte(a.host)) && l.addr.port == a.port
+}
+
+type keyDBLine struct {
+ cert bool
+ matcher matcher
+ knownKey KnownKey
+}
+
+func serialize(k ssh.PublicKey) string {
+ return k.Type() + " " + base64.StdEncoding.EncodeToString(k.Marshal())
+}
+
+func (l *keyDBLine) match(addrs []addr) bool {
+ return l.matcher.match(addrs)
+}
+
+type hostKeyDB struct {
+ // Serialized version of revoked keys
+ revoked map[string]*KnownKey
+ lines []keyDBLine
+}
+
+func newHostKeyDB() *hostKeyDB {
+ db := &hostKeyDB{
+ revoked: make(map[string]*KnownKey),
+ }
+
+ return db
+}
+
+func keyEq(a, b ssh.PublicKey) bool {
+ return bytes.Equal(a.Marshal(), b.Marshal())
+}
+
+// IsAuthority can be used as a callback in ssh.CertChecker
+func (db *hostKeyDB) IsAuthority(remote ssh.PublicKey) bool {
+ for _, l := range db.lines {
+ // TODO(hanwen): should we check the hostname against host pattern?
+ if l.cert && keyEq(l.knownKey.Key, remote) {
+ return true
+ }
+ }
+ return false
+}
+
+// IsRevoked can be used as a callback in ssh.CertChecker
+func (db *hostKeyDB) IsRevoked(key *ssh.Certificate) bool {
+ _, ok := db.revoked[string(key.Marshal())]
+ return ok
+}
+
+const markerCert = "@cert-authority"
+const markerRevoked = "@revoked"
+
+func nextWord(line []byte) (string, []byte) {
+ i := bytes.IndexAny(line, "\t ")
+ if i == -1 {
+ return string(line), nil
+ }
+
+ return string(line[:i]), bytes.TrimSpace(line[i:])
+}
+
+func parseLine(line []byte) (marker, host string, key ssh.PublicKey, err error) {
+ if w, next := nextWord(line); w == markerCert || w == markerRevoked {
+ marker = w
+ line = next
+ }
+
+ host, line = nextWord(line)
+ if len(line) == 0 {
+ return "", "", nil, errors.New("knownhosts: missing host pattern")
+ }
+
+ // ignore the keytype as it's in the key blob anyway.
+ _, line = nextWord(line)
+ if len(line) == 0 {
+ return "", "", nil, errors.New("knownhosts: missing key type pattern")
+ }
+
+ keyBlob, _ := nextWord(line)
+
+ keyBytes, err := base64.StdEncoding.DecodeString(keyBlob)
+ if err != nil {
+ return "", "", nil, err
+ }
+ key, err = ssh.ParsePublicKey(keyBytes)
+ if err != nil {
+ return "", "", nil, err
+ }
+
+ return marker, host, key, nil
+}
+
+func (db *hostKeyDB) parseLine(line []byte, filename string, linenum int) error {
+ marker, pattern, key, err := parseLine(line)
+ if err != nil {
+ return err
+ }
+
+ if marker == markerRevoked {
+ db.revoked[string(key.Marshal())] = &KnownKey{
+ Key: key,
+ Filename: filename,
+ Line: linenum,
+ }
+
+ return nil
+ }
+
+ entry := keyDBLine{
+ cert: marker == markerCert,
+ knownKey: KnownKey{
+ Filename: filename,
+ Line: linenum,
+ Key: key,
+ },
+ }
+
+ if pattern[0] == '|' {
+ entry.matcher, err = newHashedHost(pattern)
+ } else {
+ entry.matcher, err = newHostnameMatcher(pattern)
+ }
+
+ if err != nil {
+ return err
+ }
+
+ db.lines = append(db.lines, entry)
+ return nil
+}
+
+func newHostnameMatcher(pattern string) (matcher, error) {
+ var hps hostPatterns
+ for _, p := range strings.Split(pattern, ",") {
+ if len(p) == 0 {
+ continue
+ }
+
+ var a addr
+ var negate bool
+ if p[0] == '!' {
+ negate = true
+ p = p[1:]
+ }
+
+ if len(p) == 0 {
+ return nil, errors.New("knownhosts: negation without following hostname")
+ }
+
+ var err error
+ if p[0] == '[' {
+ a.host, a.port, err = net.SplitHostPort(p)
+ if err != nil {
+ return nil, err
+ }
+ } else {
+ a.host, a.port, err = net.SplitHostPort(p)
+ if err != nil {
+ a.host = p
+ a.port = "22"
+ }
+ }
+ hps = append(hps, hostPattern{
+ negate: negate,
+ addr: a,
+ })
+ }
+ return hps, nil
+}
+
+// KnownKey represents a key declared in a known_hosts file.
+type KnownKey struct {
+ Key ssh.PublicKey
+ Filename string
+ Line int
+}
+
+func (k *KnownKey) String() string {
+ return fmt.Sprintf("%s:%d: %s", k.Filename, k.Line, serialize(k.Key))
+}
+
+// KeyError is returned if we did not find the key in the host key
+// database, or there was a mismatch. Typically, in batch
+// applications, this should be interpreted as failure. Interactive
+// applications can offer an interactive prompt to the user.
+type KeyError struct {
+ // Want holds the accepted host keys. For each key algorithm,
+ // there can be one hostkey. If Want is empty, the host is
+ // unknown. If Want is non-empty, there was a mismatch, which
+ // can signify a MITM attack.
+ Want []KnownKey
+}
+
+func (u *KeyError) Error() string {
+ if len(u.Want) == 0 {
+ return "knownhosts: key is unknown"
+ }
+ return "knownhosts: key mismatch"
+}
+
+// RevokedError is returned if we found a key that was revoked.
+type RevokedError struct {
+ Revoked KnownKey
+}
+
+func (r *RevokedError) Error() string {
+ return "knownhosts: key is revoked"
+}
+
+// check checks a key against the host database. This should not be
+// used for verifying certificates.
+func (db *hostKeyDB) check(address string, remote net.Addr, remoteKey ssh.PublicKey) error {
+ if revoked := db.revoked[string(remoteKey.Marshal())]; revoked != nil {
+ return &RevokedError{Revoked: *revoked}
+ }
+
+ host, port, err := net.SplitHostPort(remote.String())
+ if err != nil {
+ return fmt.Errorf("knownhosts: SplitHostPort(%s): %v", remote, err)
+ }
+
+ addrs := []addr{
+ {host, port},
+ }
+
+ if address != "" {
+ host, port, err := net.SplitHostPort(address)
+ if err != nil {
+ return fmt.Errorf("knownhosts: SplitHostPort(%s): %v", address, err)
+ }
+
+ addrs = append(addrs, addr{host, port})
+ }
+
+ return db.checkAddrs(addrs, remoteKey)
+}
+
+// checkAddrs checks if we can find the given public key for any of
+// the given addresses. If we only find an entry for the IP address,
+// or only the hostname, then this still succeeds.
+func (db *hostKeyDB) checkAddrs(addrs []addr, remoteKey ssh.PublicKey) error {
+ // TODO(hanwen): are these the right semantics? What if there
+ // is just a key for the IP address, but not for the
+ // hostname?
+
+ // Algorithm => key.
+ knownKeys := map[string]KnownKey{}
+ for _, l := range db.lines {
+ if l.match(addrs) {
+ typ := l.knownKey.Key.Type()
+ if _, ok := knownKeys[typ]; !ok {
+ knownKeys[typ] = l.knownKey
+ }
+ }
+ }
+
+ keyErr := &KeyError{}
+ for _, v := range knownKeys {
+ keyErr.Want = append(keyErr.Want, v)
+ }
+
+ // Unknown remote host.
+ if len(knownKeys) == 0 {
+ return keyErr
+ }
+
+ // If the remote host starts using a different, unknown key type, we
+ // also interpret that as a mismatch.
+ if known, ok := knownKeys[remoteKey.Type()]; !ok || !keyEq(known.Key, remoteKey) {
+ return keyErr
+ }
+
+ return nil
+}
+
+// The Read function parses file contents.
+func (db *hostKeyDB) Read(r io.Reader, filename string) error {
+ scanner := bufio.NewScanner(r)
+
+ lineNum := 0
+ for scanner.Scan() {
+ lineNum++
+ line := scanner.Bytes()
+ line = bytes.TrimSpace(line)
+ if len(line) == 0 || line[0] == '#' {
+ continue
+ }
+
+ if err := db.parseLine(line, filename, lineNum); err != nil {
+ return fmt.Errorf("knownhosts: %s:%d: %v", filename, lineNum, err)
+ }
+ }
+ return scanner.Err()
+}
+
+// New creates a host key callback from the given OpenSSH host key
+// files. The returned callback is for use in
+// ssh.ClientConfig.HostKeyCallback. Hostnames are ignored for
+// certificates, ie. any certificate authority is assumed to be valid
+// for all remote hosts. Hashed hostnames are not supported.
+func New(files ...string) (ssh.HostKeyCallback, error) {
+ db := newHostKeyDB()
+ for _, fn := range files {
+ f, err := os.Open(fn)
+ if err != nil {
+ return nil, err
+ }
+ defer f.Close()
+ if err := db.Read(f, fn); err != nil {
+ return nil, err
+ }
+ }
+
+ // TODO(hanwen): properly supporting certificates requires an
+ // API change in the SSH library: IsAuthority should provide
+ // the address too?
+
+ var certChecker ssh.CertChecker
+ certChecker.IsAuthority = db.IsAuthority
+ certChecker.IsRevoked = db.IsRevoked
+ certChecker.HostKeyFallback = db.check
+
+ return certChecker.CheckHostKey, nil
+}
+
+// Normalize normalizes an address into the form used in known_hosts
+func Normalize(address string) string {
+ host, port, err := net.SplitHostPort(address)
+ if err != nil {
+ host = address
+ port = "22"
+ }
+ entry := host
+ if port != "22" {
+ entry = "[" + entry + "]:" + port
+ } else if strings.Contains(host, ":") && !strings.HasPrefix(host, "[") {
+ entry = "[" + entry + "]"
+ }
+ return entry
+}
+
+// Line returns a line to add append to the known_hosts files.
+func Line(addresses []string, key ssh.PublicKey) string {
+ var trimmed []string
+ for _, a := range addresses {
+ trimmed = append(trimmed, Normalize(a))
+ }
+
+ return strings.Join(trimmed, ",") + " " + serialize(key)
+}
+
+// HashHostname hashes the given hostname. The hostname is not
+// normalized before hashing.
+func HashHostname(hostname string) string {
+ // TODO(hanwen): check if we can safely normalize this always.
+ salt := make([]byte, sha1.Size)
+
+ _, err := rand.Read(salt)
+ if err != nil {
+ panic(fmt.Sprintf("crypto/rand failure %v", err))
+ }
+
+ hash := hashHost(hostname, salt)
+ return encodeHash(sha1HashType, salt, hash)
+}
+
+func decodeHash(encoded string) (hashType string, salt, hash []byte, err error) {
+ if len(encoded) == 0 || encoded[0] != '|' {
+ err = errors.New("knownhosts: hashed host must start with '|'")
+ return
+ }
+ components := strings.Split(encoded, "|")
+ if len(components) != 4 {
+ err = fmt.Errorf("knownhosts: got %d components, want 3", len(components))
+ return
+ }
+
+ hashType = components[1]
+ if salt, err = base64.StdEncoding.DecodeString(components[2]); err != nil {
+ return
+ }
+ if hash, err = base64.StdEncoding.DecodeString(components[3]); err != nil {
+ return
+ }
+ return
+}
+
+func encodeHash(typ string, salt []byte, hash []byte) string {
+ return strings.Join([]string{"",
+ typ,
+ base64.StdEncoding.EncodeToString(salt),
+ base64.StdEncoding.EncodeToString(hash),
+ }, "|")
+}
+
+// See https://android.googlesource.com/platform/external/openssh/+/ab28f5495c85297e7a597c1ba62e996416da7c7e/hostfile.c#120
+func hashHost(hostname string, salt []byte) []byte {
+ mac := hmac.New(sha1.New, salt)
+ mac.Write([]byte(hostname))
+ return mac.Sum(nil)
+}
+
+type hashedHost struct {
+ salt []byte
+ hash []byte
+}
+
+const sha1HashType = "1"
+
+func newHashedHost(encoded string) (*hashedHost, error) {
+ typ, salt, hash, err := decodeHash(encoded)
+ if err != nil {
+ return nil, err
+ }
+
+ // The type field seems for future algorithm agility, but it's
+ // actually hardcoded in openssh currently, see
+ // https://android.googlesource.com/platform/external/openssh/+/ab28f5495c85297e7a597c1ba62e996416da7c7e/hostfile.c#120
+ if typ != sha1HashType {
+ return nil, fmt.Errorf("knownhosts: got hash type %s, must be '1'", typ)
+ }
+
+ return &hashedHost{salt: salt, hash: hash}, nil
+}
+
+func (h *hashedHost) match(addrs []addr) bool {
+ for _, a := range addrs {
+ if bytes.Equal(hashHost(Normalize(a.String()), h.salt), h.hash) {
+ return true
+ }
+ }
+ return false
+}
generated by cgit v1.2.3-1-g7c22 (git 2.25.1) at 2024-05-20 13:49:24 +0000