diff --git a/ssh/certs.go b/ssh/certs.go index 9962ff0..a7426b6 100644 --- a/ssh/certs.go +++ b/ssh/certs.go @@ -85,46 +85,73 @@ func marshalStringList(namelist []string) []byte { return to } +type optionsTuple struct { + Key string + Value []byte +} + +type optionsTupleValue struct { + Value string +} + +// serialize a map of critical options or extensions +// issue #10569 - per [PROTOCOL.certkeys] and SSH implementation, +// we need two length prefixes for a non-empty string value func marshalTuples(tups map[string]string) []byte { keys := make([]string, 0, len(tups)) - for k := range tups { - keys = append(keys, k) + for key := range tups { + keys = append(keys, key) } sort.Strings(keys) - var r []byte - for _, k := range keys { - s := struct{ K, V string }{k, tups[k]} - r = append(r, Marshal(&s)...) + var ret []byte + for _, key := range keys { + s := optionsTuple{Key: key} + if value := tups[key]; len(value) > 0 { + s.Value = Marshal(&optionsTupleValue{value}) + } + ret = append(ret, Marshal(&s)...) } - return r + return ret } +// issue #10569 - per [PROTOCOL.certkeys] and SSH implementation, +// we need two length prefixes for a non-empty option value func parseTuples(in []byte) (map[string]string, error) { tups := map[string]string{} var lastKey string var haveLastKey bool for len(in) > 0 { - nameBytes, rest, ok := parseString(in) - if !ok { - return nil, errShortRead - } - data, rest, ok := parseString(rest) - if !ok { - return nil, errShortRead - } - name := string(nameBytes) + var key, val, extra []byte + var ok bool + if key, in, ok = parseString(in); !ok { + return nil, errShortRead + } + keyStr := string(key) // according to [PROTOCOL.certkeys], the names must be in // lexical order. - if haveLastKey && name <= lastKey { + if haveLastKey && keyStr <= lastKey { return nil, fmt.Errorf("ssh: certificate options are not in lexical order") } - lastKey, haveLastKey = name, true - - tups[name] = string(data) - in = rest + lastKey, haveLastKey = keyStr, true + // the next field is a data field, which if non-empty has a string embedded + if val, in, ok = parseString(in); !ok { + return nil, errShortRead + } + if len(val) > 0 { + val, extra, ok = parseString(val) + if !ok { + return nil, errShortRead + } + if len(extra) > 0 { + return nil, fmt.Errorf("ssh: unexpected trailing data after certificate option value") + } + tups[keyStr] = string(val) + } else { + tups[keyStr] = "" + } } return tups, nil } diff --git a/ssh/certs_test.go b/ssh/certs_test.go index 7d1b00f..33236f5 100644 --- a/ssh/certs_test.go +++ b/ssh/certs_test.go @@ -7,13 +7,14 @@ package ssh import ( "bytes" "crypto/rand" + "reflect" "testing" "time" ) // Cert generated by ssh-keygen 6.0p1 Debian-4. // % ssh-keygen -s ca-key -I test user-key -var exampleSSHCert = `ssh-rsa-cert-v01@openssh.com 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` +const exampleSSHCert = `ssh-rsa-cert-v01@openssh.com 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` func TestParseCert(t *testing.T) { authKeyBytes := []byte(exampleSSHCert) @@ -27,7 +28,7 @@ func TestParseCert(t *testing.T) { } if _, ok := key.(*Certificate); !ok { - t.Fatalf("got %#v, want *Certificate", key) + t.Fatalf("got %v (%T), want *Certificate", key, key) } marshaled := MarshalAuthorizedKey(key) @@ -39,6 +40,60 @@ func TestParseCert(t *testing.T) { } } +// Cert generated by ssh-keygen OpenSSH_6.8p1 OS X 10.10.3 +// % ssh-keygen -s ca -I testcert -O source-address=192.168.1.0/24 -O force-command=/bin/sleep user.pub +// user.pub key: ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDACh1rt2DXfV3hk6fszSQcQ/rueMId0kVD9U7nl8cfEnFxqOCrNT92g4laQIGl2mn8lsGZfTLg8ksHq3gkvgO3oo/0wHy4v32JeBOHTsN5AL4gfHNEhWeWb50ev47hnTsRIt9P4dxogeUo/hTu7j9+s9lLpEQXCvq6xocXQt0j8MV9qZBBXFLXVT3cWIkSqOdwt/5ZBg+1GSrc7WfCXVWgTk4a20uPMuJPxU4RQwZW6X3+O8Pqo8C3cW0OzZRFP6gUYUKUsTI5WntlS+LAxgw1mZNsozFGdbiOPRnEryE3SRldh9vjDR3tin1fGpA5P7+CEB/bqaXtG3V+F2OkqaMN +// Critical Options: +// force-command /bin/sleep +// source-address 192.168.1.0/24 +// Extensions: +// permit-X11-forwarding +// permit-agent-forwarding +// permit-port-forwarding +// permit-pty +// permit-user-rc +const exampleSSHCertWithOptions = `ssh-rsa-cert-v01@openssh.com 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` + +func TestParseCertWithOptions(t *testing.T) { + opts := map[string]string{ + "source-address": "192.168.1.0/24", + "force-command": "/bin/sleep", + } + exts := map[string]string{ + "permit-X11-forwarding": "", + "permit-agent-forwarding": "", + "permit-port-forwarding": "", + "permit-pty": "", + "permit-user-rc": "", + } + authKeyBytes := []byte(exampleSSHCertWithOptions) + + key, _, _, rest, err := ParseAuthorizedKey(authKeyBytes) + if err != nil { + t.Fatalf("ParseAuthorizedKey: %v", err) + } + if len(rest) > 0 { + t.Errorf("rest: got %q, want empty", rest) + } + cert, ok := key.(*Certificate) + if !ok { + t.Fatalf("got %v (%T), want *Certificate", key, key) + } + if !reflect.DeepEqual(cert.CriticalOptions, opts) { + t.Errorf("unexpected critical options - got %v, want %v", cert.CriticalOptions, opts) + } + if !reflect.DeepEqual(cert.Extensions, exts) { + t.Errorf("unexpected Extensions - got %v, want %v", cert.Extensions, exts) + } + marshaled := MarshalAuthorizedKey(key) + // Before comparison, remove the trailing newline that + // MarshalAuthorizedKey adds. + marshaled = marshaled[:len(marshaled)-1] + if !bytes.Equal(authKeyBytes, marshaled) { + t.Errorf("marshaled certificate does not match original: got %q, want %q", marshaled, authKeyBytes) + } +} + func TestValidateCert(t *testing.T) { key, _, _, _, err := ParseAuthorizedKey([]byte(exampleSSHCert)) if err != nil {