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@@ -45,75 +45,32 @@ import (
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const (
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- defaultPrivateRSAKeyName = "id_rsa"
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- defaultPrivateECDSAKeyName = "id_ecdsa"
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- defaultPrivateEd25519KeyName = "id_ed25519"
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- sourceAddressCriticalOption = "source-address"
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- kexDHGroupExchangeSHA1 = "diffie-hellman-group-exchange-sha1"
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- kexDHGroupExchangeSHA256 = "diffie-hellman-group-exchange-sha256"
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+ defaultPrivateRSAKeyName = "id_rsa"
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+ defaultPrivateECDSAKeyName = "id_ecdsa"
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+ defaultPrivateEd25519KeyName = "id_ed25519"
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+ sourceAddressCriticalOption = "source-address"
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+ keyExchangeCurve25519SHA256LibSSH = "[email protected]"
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)
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var (
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+ supportedAlgos = ssh.SupportedAlgorithms()
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+ insecureAlgos = ssh.InsecureAlgorithms()
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sftpExtensions = []string{"[email protected]"}
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- supportedHostKeyAlgos = []string{
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- ssh.CertAlgoRSASHA512v01, ssh.CertAlgoRSASHA256v01,
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- ssh.CertAlgoRSAv01, ssh.CertAlgoDSAv01, ssh.CertAlgoECDSA256v01,
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- ssh.CertAlgoECDSA384v01, ssh.CertAlgoECDSA521v01, ssh.CertAlgoED25519v01,
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- ssh.KeyAlgoECDSA256, ssh.KeyAlgoECDSA384, ssh.KeyAlgoECDSA521,
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- ssh.KeyAlgoRSASHA512, ssh.KeyAlgoRSASHA256,
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- ssh.KeyAlgoRSA, ssh.KeyAlgoDSA,
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- ssh.KeyAlgoED25519,
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- }
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+ supportedHostKeyAlgos = append(supportedAlgos.HostKeys, insecureAlgos.HostKeys...)
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preferredHostKeyAlgos = []string{
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ssh.KeyAlgoRSASHA256, ssh.KeyAlgoRSASHA512,
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ssh.KeyAlgoECDSA256, ssh.KeyAlgoECDSA384, ssh.KeyAlgoECDSA521,
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ssh.KeyAlgoED25519,
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}
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- supportedPublicKeyAlgos = []string{
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- ssh.KeyAlgoED25519,
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- ssh.KeyAlgoSKED25519, ssh.KeyAlgoSKECDSA256,
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- ssh.KeyAlgoECDSA256, ssh.KeyAlgoECDSA384, ssh.KeyAlgoECDSA521,
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- ssh.KeyAlgoRSASHA256, ssh.KeyAlgoRSASHA512, ssh.KeyAlgoRSA,
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- ssh.KeyAlgoDSA,
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- }
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- preferredPublicKeyAlgos = []string{
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- ssh.KeyAlgoED25519,
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- ssh.KeyAlgoSKED25519, ssh.KeyAlgoSKECDSA256,
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- ssh.KeyAlgoECDSA256, ssh.KeyAlgoECDSA384, ssh.KeyAlgoECDSA521,
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- ssh.KeyAlgoRSASHA256, ssh.KeyAlgoRSASHA512,
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- }
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- supportedKexAlgos = []string{
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- "curve25519-sha256", "[email protected]",
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- "ecdh-sha2-nistp256", "ecdh-sha2-nistp384", "ecdh-sha2-nistp521",
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- "diffie-hellman-group14-sha256", "diffie-hellman-group16-sha512",
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- "diffie-hellman-group18-sha512", "diffie-hellman-group14-sha1",
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- "diffie-hellman-group1-sha1",
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- }
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- preferredKexAlgos = []string{
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- "curve25519-sha256", "[email protected]",
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- "ecdh-sha2-nistp256", "ecdh-sha2-nistp384", "ecdh-sha2-nistp521",
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- "diffie-hellman-group14-sha256",
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- }
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- supportedCiphers = []string{
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- "[email protected]", "[email protected]",
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- "[email protected]",
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- "aes128-ctr", "aes192-ctr", "aes256-ctr",
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- "aes128-cbc", "aes192-cbc", "aes256-cbc",
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- "3des-cbc",
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- "arcfour", "arcfour128", "arcfour256",
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- }
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- preferredCiphers = []string{
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- "[email protected]", "[email protected]",
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- "[email protected]",
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- "aes128-ctr", "aes192-ctr", "aes256-ctr",
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- }
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- supportedMACs = []string{
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- "[email protected]", "hmac-sha2-256",
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- "[email protected]", "hmac-sha2-512",
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- "hmac-sha1", "hmac-sha1-96",
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- }
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- preferredMACs = []string{
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- "[email protected]", "hmac-sha2-256",
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+ supportedPublicKeyAlgos = append(supportedAlgos.PublicKeyAuths, insecureAlgos.PublicKeyAuths...)
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+ preferredPublicKeyAlgos = supportedAlgos.PublicKeyAuths
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+ supportedKexAlgos = append(supportedAlgos.KeyExchanges, insecureAlgos.KeyExchanges...)
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+ preferredKexAlgos = supportedAlgos.KeyExchanges
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+ supportedCiphers = append(supportedAlgos.Ciphers, insecureAlgos.Ciphers...)
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+ preferredCiphers = supportedAlgos.Ciphers
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+ supportedMACs = append(supportedAlgos.MACs, insecureAlgos.MACs...)
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+ preferredMACs = []string{
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+ ssh.HMACSHA256ETM, ssh.HMACSHA256,
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}
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revokedCertManager = revokedCertificates{
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@@ -170,12 +127,6 @@ type Configuration struct {
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// HostKeyAlgorithms lists the public key algorithms that the server will accept for host
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// key authentication.
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HostKeyAlgorithms []string `json:"host_key_algorithms" mapstructure:"host_key_algorithms"`
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- // Diffie-Hellman moduli files.
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- // Each moduli file can be defined as a path relative to the configuration directory or an absolute one.
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- // If set and valid, "diffie-hellman-group-exchange-sha256" and "diffie-hellman-group-exchange-sha1" KEX algorithms
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- // will be available, `diffie-hellman-group-exchange-sha256` will be enabled by default if you
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- // don't explicitly set KEXs
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- Moduli []string `json:"moduli" mapstructure:"moduli"`
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// KexAlgorithms specifies the available KEX (Key Exchange) algorithms in
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// preference order.
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KexAlgorithms []string `json:"kex_algorithms" mapstructure:"kex_algorithms"`
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@@ -373,8 +324,6 @@ func (c *Configuration) Initialize(configDir string) error {
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return common.ErrNoBinding
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}
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- c.loadModuli(configDir)
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-
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sftp.SetSFTPExtensions(sftpExtensions...) //nolint:errcheck // we configure valid SFTP Extensions so we cannot get an error
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sftp.MaxFilelist = vfs.ListerBatchSize
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@@ -491,21 +440,34 @@ func (c *Configuration) configureKeyAlgos(serverConfig *ssh.ServerConfig) error
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return nil
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}
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+func (c *Configuration) checkKeyExchangeAlgorithms() {
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+ var kexs []string
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+ for _, k := range c.KexAlgorithms {
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+ if k == "diffie-hellman-group18-sha512" {
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+ logger.Warn(logSender, "", "KEX %q is not supported and will be ignored", k)
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+ continue
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+ }
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+ kexs = append(kexs, k)
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+ if strings.TrimSpace(k) == keyExchangeCurve25519SHA256LibSSH {
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+ kexs = append(kexs, ssh.KeyExchangeCurve25519SHA256)
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+ }
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+ if strings.TrimSpace(k) == ssh.KeyExchangeCurve25519SHA256 {
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+ kexs = append(kexs, keyExchangeCurve25519SHA256LibSSH)
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+ }
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+ }
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+ c.KexAlgorithms = util.RemoveDuplicates(kexs, true)
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+}
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+
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func (c *Configuration) configureSecurityOptions(serverConfig *ssh.ServerConfig) error {
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if err := c.configureKeyAlgos(serverConfig); err != nil {
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return err
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}
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if len(c.KexAlgorithms) > 0 {
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- hasDHGroupKEX := util.Contains(supportedKexAlgos, kexDHGroupExchangeSHA256)
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- if !hasDHGroupKEX {
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- c.KexAlgorithms = util.Remove(c.KexAlgorithms, kexDHGroupExchangeSHA1)
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- c.KexAlgorithms = util.Remove(c.KexAlgorithms, kexDHGroupExchangeSHA256)
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- }
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- c.KexAlgorithms = util.RemoveDuplicates(c.KexAlgorithms, true)
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+ c.checkKeyExchangeAlgorithms()
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for _, kex := range c.KexAlgorithms {
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- if kex == "diffie-hellman-group18-sha512" {
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- logger.Warn(logSender, "", "KEX %q is not supported and will be ignored", kex)
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+ if kex == keyExchangeCurve25519SHA256LibSSH {
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+ continue
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}
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if !util.Contains(supportedKexAlgos, kex) {
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return fmt.Errorf("unsupported key-exchange algorithm %q", kex)
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@@ -513,6 +475,7 @@ func (c *Configuration) configureSecurityOptions(serverConfig *ssh.ServerConfig)
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}
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} else {
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c.KexAlgorithms = preferredKexAlgos
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+ c.checkKeyExchangeAlgorithms()
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}
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serverConfig.KeyExchanges = c.KexAlgorithms
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serviceStatus.KexAlgorithms = c.KexAlgorithms
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@@ -643,8 +606,8 @@ func (c *Configuration) AcceptInboundConnection(conn net.Conn, config *ssh.Serve
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}
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logger.Log(logger.LevelInfo, common.ProtocolSSH, connectionID,
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- "User %q logged in with %q, from ip %q, client version %q", user.Username, loginType,
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- ipAddr, string(sconn.ClientVersion()))
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+ "User %q logged in with %q, from ip %q, client version %q, negotiated algorithms: %+v",
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+ user.Username, loginType, ipAddr, string(sconn.ClientVersion()), sconn.Conn.(ssh.AlgorithmsConnMetadata).Algorithms())
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dataprovider.UpdateLastLogin(&user)
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sshConnection := common.NewSSHConnection(connectionID, conn)
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@@ -812,7 +775,8 @@ func checkAuthError(ip string, err error) {
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common.AddDefenderEvent(ip, common.ProtocolSSH, common.HostEventNoLoginTried)
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dataprovider.ExecutePostLoginHook(&dataprovider.User{}, dataprovider.LoginMethodNoAuthTried, ip, common.ProtocolSSH, err)
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logEv := notifier.LogEventTypeNoLoginTried
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- if errors.Is(err, ssh.ErrNoCommonAlgo) {
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+ var negotiationError *ssh.AlgorithmNegotiationError
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+ if errors.As(err, &negotiationError) {
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logEv = notifier.LogEventTypeNotNegotiated
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}
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plugin.Handler.NotifyLogEvent(logEv, common.ProtocolSSH, "", ip, "", err)
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@@ -851,7 +815,7 @@ func loginUser(user *dataprovider.User, loginMethod, publicKey string, conn ssh.
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user.Username)
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return nil, fmt.Errorf("second factor authentication is not set for user %q", user.Username)
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}
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- remoteAddr := conn.RemoteAddr().String()
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+ remoteAddr := util.GetIPFromRemoteAddress(conn.RemoteAddr().String())
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if !user.IsLoginFromAddrAllowed(remoteAddr) {
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logger.Info(logSender, connectionID, "cannot login user %q, remote address is not allowed: %v",
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user.Username, remoteAddr)
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@@ -981,38 +945,6 @@ func (c *Configuration) checkHostKeyAutoGeneration(configDir string) error {
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return nil
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}
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-func (c *Configuration) loadModuli(configDir string) {
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- supportedKexAlgos = util.Remove(supportedKexAlgos, kexDHGroupExchangeSHA1)
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- supportedKexAlgos = util.Remove(supportedKexAlgos, kexDHGroupExchangeSHA256)
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- preferredKexAlgos = util.Remove(preferredKexAlgos, kexDHGroupExchangeSHA256)
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- c.Moduli = util.RemoveDuplicates(c.Moduli, false)
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- for _, m := range c.Moduli {
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- m = strings.TrimSpace(m)
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- if !util.IsFileInputValid(m) {
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- logger.Warn(logSender, "", "unable to load invalid moduli file %q", m)
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- logger.WarnToConsole("unable to load invalid host moduli file %q", m)
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- continue
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- }
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- if !filepath.IsAbs(m) {
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- m = filepath.Join(configDir, m)
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- }
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- logger.Info(logSender, "", "loading moduli file %q", m)
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- if err := ssh.ParseModuli(m); err != nil {
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- logger.Warn(logSender, "", "ignoring moduli file %q, error: %v", m, err)
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- continue
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- }
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- if !util.Contains(supportedKexAlgos, kexDHGroupExchangeSHA1) {
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- supportedKexAlgos = append(supportedKexAlgos, kexDHGroupExchangeSHA1)
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- }
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- if !util.Contains(supportedKexAlgos, kexDHGroupExchangeSHA256) {
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- supportedKexAlgos = append(supportedKexAlgos, kexDHGroupExchangeSHA256)
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- }
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- if !util.Contains(preferredKexAlgos, kexDHGroupExchangeSHA256) {
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- preferredKexAlgos = append(preferredKexAlgos, kexDHGroupExchangeSHA256)
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- }
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- }
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-}
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-
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func (c *Configuration) getHostKeyAlgorithms(keyFormat string) []string {
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var algos []string
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for _, algo := range algorithmsForKeyFormat(keyFormat) {
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@@ -1188,12 +1120,12 @@ func (c *Configuration) initializeCertChecker(configDir string) error {
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func (c *Configuration) getPartialSuccessError(nextAuthMethods []string) error {
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err := &ssh.PartialSuccessError{}
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if c.PasswordAuthentication && util.Contains(nextAuthMethods, dataprovider.LoginMethodPassword) {
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- err.PasswordCallback = func(conn ssh.ConnMetadata, password []byte) (*ssh.Permissions, error) {
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+ err.Next.PasswordCallback = func(conn ssh.ConnMetadata, password []byte) (*ssh.Permissions, error) {
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return c.validatePasswordCredentials(conn, password, dataprovider.SSHLoginMethodKeyAndPassword)
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}
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}
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if c.KeyboardInteractiveAuthentication && util.Contains(nextAuthMethods, dataprovider.SSHLoginMethodKeyboardInteractive) {
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- err.KeyboardInteractiveCallback = func(conn ssh.ConnMetadata, client ssh.KeyboardInteractiveChallenge) (*ssh.Permissions, error) {
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+ err.Next.KeyboardInteractiveCallback = func(conn ssh.ConnMetadata, client ssh.KeyboardInteractiveChallenge) (*ssh.Permissions, error) {
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return c.validateKeyboardInteractiveCredentials(conn, client, dataprovider.SSHLoginMethodKeyAndKeyboardInt, true)
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}
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}
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Nicola Murino