From: Sage Weil <sage@redhat.com>
Date: Thu, 24 May 2018 18:57:17 +0000 (-0500)
Subject: auth/cephx: add authorizer challenge
X-Git-Tag: v14.0.1~913^2~2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=f80b848d3f830eb6dba50123e04385173fa4540b;p=ceph.git

auth/cephx: add authorizer challenge

Allow the accepting side of a connection to reject an initial authorizer
with a random challenge.  The connecting side then has to respond with an
updated authorizer proving they are able to decrypt the service's challenge
and that the new authorizer was produced for this specific connection
instance.

The accepting side requires this challenge and response unconditionally
if the client side advertises they have the feature bit.  Servers wishing
to require this improved level of authentication simply have to require
the appropriate feature.

Signed-off-by: Sage Weil <sage@redhat.com>
---

diff --git a/src/auth/Auth.h b/src/auth/Auth.h
index 9b8601192b75..672f0fda1e45 100644
--- a/src/auth/Auth.h
+++ b/src/auth/Auth.h
@@ -142,6 +142,11 @@ struct AuthAuthorizer {
   explicit AuthAuthorizer(__u32 p) : protocol(p) {}
   virtual ~AuthAuthorizer() {}
   virtual bool verify_reply(bufferlist::const_iterator& reply) = 0;
+  virtual bool add_challenge(CephContext *cct, bufferlist& challenge) = 0;
+};
+
+struct AuthAuthorizerChallenge {
+  virtual ~AuthAuthorizerChallenge() {}
 };
 
 
diff --git a/src/auth/AuthAuthorizeHandler.h b/src/auth/AuthAuthorizeHandler.h
index c53d049fa0a2..f6a0e68c9598 100644
--- a/src/auth/AuthAuthorizeHandler.h
+++ b/src/auth/AuthAuthorizeHandler.h
@@ -34,7 +34,9 @@ struct AuthAuthorizeHandler {
   virtual bool verify_authorizer(CephContext *cct, KeyStore *keys,
 				 bufferlist& authorizer_data, bufferlist& authorizer_reply,
                                  EntityName& entity_name, uint64_t& global_id,
-				 AuthCapsInfo& caps_info, CryptoKey& session_key, uint64_t *auid = NULL) = 0;
+				 AuthCapsInfo& caps_info, CryptoKey& session_key,
+				 uint64_t *auid,
+				 std::unique_ptr<AuthAuthorizerChallenge> *challenge) = 0;
   virtual int authorizer_session_crypto() = 0;
 };
 
diff --git a/src/auth/cephx/CephxAuthorizeHandler.cc b/src/auth/cephx/CephxAuthorizeHandler.cc
index ced50fddda60..e589ff4ee7e9 100644
--- a/src/auth/cephx/CephxAuthorizeHandler.cc
+++ b/src/auth/cephx/CephxAuthorizeHandler.cc
@@ -6,9 +6,12 @@
 
 
 
-bool CephxAuthorizeHandler::verify_authorizer(CephContext *cct, KeyStore *keys,
-					      bufferlist& authorizer_data, bufferlist& authorizer_reply,
-                                              EntityName& entity_name, uint64_t& global_id, AuthCapsInfo& caps_info, CryptoKey& session_key,  uint64_t *auid)
+bool CephxAuthorizeHandler::verify_authorizer(
+  CephContext *cct, KeyStore *keys,
+  bufferlist& authorizer_data, bufferlist& authorizer_reply,
+  EntityName& entity_name, uint64_t& global_id, AuthCapsInfo& caps_info,
+  CryptoKey& session_key, uint64_t *auid,
+  std::unique_ptr<AuthAuthorizerChallenge> *challenge)
 {
   auto iter = authorizer_data.cbegin();
 
@@ -19,7 +22,8 @@ bool CephxAuthorizeHandler::verify_authorizer(CephContext *cct, KeyStore *keys,
 
   CephXServiceTicketInfo auth_ticket_info;
 
-  bool isvalid = cephx_verify_authorizer(cct, keys, iter, auth_ticket_info, authorizer_reply);
+  bool isvalid = cephx_verify_authorizer(cct, keys, iter, auth_ticket_info, challenge,
+					 authorizer_reply);
 
   if (isvalid) {
     caps_info = auth_ticket_info.ticket.caps;
diff --git a/src/auth/cephx/CephxAuthorizeHandler.h b/src/auth/cephx/CephxAuthorizeHandler.h
index 7246b80c71da..8fa40aa71275 100644
--- a/src/auth/cephx/CephxAuthorizeHandler.h
+++ b/src/auth/cephx/CephxAuthorizeHandler.h
@@ -23,7 +23,8 @@ struct CephxAuthorizeHandler : public AuthAuthorizeHandler {
   bool verify_authorizer(CephContext *cct, KeyStore *keys,
 			 bufferlist& authorizer_data, bufferlist& authorizer_reply,
                          EntityName& entity_name, uint64_t& global_id,
-			 AuthCapsInfo& caps_info, CryptoKey& session_key, uint64_t *auid = NULL) override;
+			 AuthCapsInfo& caps_info, CryptoKey& session_key, uint64_t *auid,
+			 std::unique_ptr<AuthAuthorizerChallenge> *challenge) override;
   int authorizer_session_crypto() override;
 };
 
diff --git a/src/auth/cephx/CephxProtocol.cc b/src/auth/cephx/CephxProtocol.cc
index cf103e9f2940..b8a62dbb732c 100644
--- a/src/auth/cephx/CephxProtocol.cc
+++ b/src/auth/cephx/CephxProtocol.cc
@@ -304,6 +304,7 @@ CephXAuthorizer *CephXTicketHandler::build_authorizer(uint64_t global_id) const
   encode(service_id, a->bl);
 
   encode(ticket, a->bl);
+  a->base_bl = a->bl;
 
   CephXAuthorize msg;
   msg.nonce = a->nonce;
@@ -390,7 +391,9 @@ bool cephx_decode_ticket(CephContext *cct, KeyStore *keys, uint32_t service_id,
  */
 bool cephx_verify_authorizer(CephContext *cct, KeyStore *keys,
 			     bufferlist::const_iterator& indata,
-			     CephXServiceTicketInfo& ticket_info, bufferlist& reply_bl)
+			     CephXServiceTicketInfo& ticket_info,
+			     std::unique_ptr<AuthAuthorizerChallenge> *challenge,
+			     bufferlist& reply_bl)
 {
   __u8 authorizer_v;
   uint32_t service_id;
@@ -457,6 +460,30 @@ bool cephx_verify_authorizer(CephContext *cct, KeyStore *keys,
     return false;
   }
 
+  if (challenge) {
+    auto *c = static_cast<CephXAuthorizeChallenge*>(challenge->get());
+    if (!auth_msg.have_challenge || !c) {
+      c = new CephXAuthorizeChallenge;
+      challenge->reset(c);
+      cct->random()->get_bytes((char*)&c->server_challenge, sizeof(c->server_challenge));
+      ldout(cct,10) << __func__ << " adding server_challenge " << c->server_challenge
+		    << dendl;
+
+      encode_encrypt_enc_bl(cct, *c, ticket_info.session_key, reply_bl, error);
+      if (!error.empty()) {
+	ldout(cct, 10) << "verify_authorizer: encode_encrypt error: " << error << dendl;
+	return false;
+      }
+      return false;
+    }
+    ldout(cct, 10) << __func__ << " got server_challenge+1 "
+		   << auth_msg.server_challenge_plus_one
+		   << " expecting " << c->server_challenge + 1 << dendl;
+    if (c->server_challenge + 1 != auth_msg.server_challenge_plus_one) {
+      return false;
+    }
+  }
+
   /*
    * Reply authorizer:
    *  {timestamp + 1}^session_key
@@ -493,3 +520,31 @@ bool CephXAuthorizer::verify_reply(bufferlist::const_iterator& indata)
   return true;
 }
 
+bool CephXAuthorizer::add_challenge(CephContext *cct, bufferlist& challenge)
+{
+  bl = base_bl;
+
+  CephXAuthorize msg;
+  msg.nonce = nonce;
+
+  auto p = challenge.begin();
+  if (!p.end()) {
+    std::string error;
+    CephXAuthorizeChallenge ch;
+    decode_decrypt_enc_bl(cct, ch, session_key, challenge, error);
+    if (!error.empty()) {
+      ldout(cct, 0) << "failed to decrypt challenge (" << challenge.length() << " bytes): "
+		    << error << dendl;
+      return false;
+    }
+    msg.have_challenge = true;
+    msg.server_challenge_plus_one = ch.server_challenge + 1;
+  }
+
+  std::string error;
+  if (encode_encrypt(cct, msg, session_key, bl, error)) {
+    ldout(cct, 0) << __func__ << " failed to encrypt authorizer: " << error << dendl;
+    return false;
+  }
+  return true;
+}
diff --git a/src/auth/cephx/CephxProtocol.h b/src/auth/cephx/CephxProtocol.h
index 055a233cba3b..16135ec11f31 100644
--- a/src/auth/cephx/CephxProtocol.h
+++ b/src/auth/cephx/CephxProtocol.h
@@ -289,12 +289,14 @@ private:
   CephContext *cct;
 public:
   uint64_t nonce;
+  bufferlist base_bl;
 
   explicit CephXAuthorizer(CephContext *cct_)
     : AuthAuthorizer(CEPH_AUTH_CEPHX), cct(cct_), nonce(0) {}
 
   bool build_authorizer();
   bool verify_reply(bufferlist::const_iterator& reply) override;
+  bool add_challenge(CephContext *cct, bufferlist& challenge) override;
 };
 
 
@@ -404,19 +406,44 @@ struct CephXServiceTicketInfo {
 };
 WRITE_CLASS_ENCODER(CephXServiceTicketInfo)
 
+struct CephXAuthorizeChallenge : public AuthAuthorizerChallenge {
+  uint64_t server_challenge;
+  void encode(bufferlist& bl) const {
+    using ceph::encode;
+    __u8 struct_v = 1;
+    encode(struct_v, bl);
+    encode(server_challenge, bl);
+  }
+  void decode(bufferlist::const_iterator& bl) {
+    using ceph::decode;
+    __u8 struct_v;
+    decode(struct_v, bl);
+    decode(server_challenge, bl);
+  }
+};
+WRITE_CLASS_ENCODER(CephXAuthorizeChallenge)
+
 struct CephXAuthorize {
   uint64_t nonce;
+  bool have_challenge = false;
+  uint64_t server_challenge_plus_one = 0;
   void encode(bufferlist& bl) const {
     using ceph::encode;
-    __u8 struct_v = 1;
+    __u8 struct_v = 2;
     encode(struct_v, bl);
     encode(nonce, bl);
+    encode(have_challenge, bl);
+    encode(server_challenge_plus_one, bl);
   }
   void decode(bufferlist::const_iterator& bl) {
     using ceph::decode;
     __u8 struct_v;
     decode(struct_v, bl);
     decode(nonce, bl);
+    if (struct_v >= 2) {
+      decode(have_challenge, bl);
+      decode(server_challenge_plus_one, bl);
+    }
   }
 };
 WRITE_CLASS_ENCODER(CephXAuthorize)
@@ -431,9 +458,12 @@ bool cephx_decode_ticket(CephContext *cct, KeyStore *keys,
 /*
  * Verify authorizer and generate reply authorizer
  */
-extern bool cephx_verify_authorizer(CephContext *cct, KeyStore *keys,
-				    bufferlist::const_iterator& indata,
-				    CephXServiceTicketInfo& ticket_info, bufferlist& reply_bl);
+extern bool cephx_verify_authorizer(
+  CephContext *cct, KeyStore *keys,
+  bufferlist::const_iterator& indata,
+  CephXServiceTicketInfo& ticket_info,
+  std::unique_ptr<AuthAuthorizerChallenge> *challenge,
+  bufferlist& reply_bl);
 
 
 
diff --git a/src/auth/cephx/CephxServiceHandler.cc b/src/auth/cephx/CephxServiceHandler.cc
index acd9fa64b724..ea2d852cae1b 100644
--- a/src/auth/cephx/CephxServiceHandler.cc
+++ b/src/auth/cephx/CephxServiceHandler.cc
@@ -153,7 +153,9 @@ int CephxServiceHandler::handle_request(bufferlist::const_iterator& indata, buff
 
       bufferlist tmp_bl;
       CephXServiceTicketInfo auth_ticket_info;
-      if (!cephx_verify_authorizer(cct, key_server, indata, auth_ticket_info, tmp_bl)) {
+      // note: no challenge here.
+      if (!cephx_verify_authorizer(cct, key_server, indata, auth_ticket_info, nullptr,
+				   tmp_bl)) {
         ret = -EPERM;
 	break;
       }
diff --git a/src/auth/none/AuthNoneAuthorizeHandler.cc b/src/auth/none/AuthNoneAuthorizeHandler.cc
index 298d21bd2a2b..d7e42c1b9ac7 100644
--- a/src/auth/none/AuthNoneAuthorizeHandler.cc
+++ b/src/auth/none/AuthNoneAuthorizeHandler.cc
@@ -17,10 +17,13 @@
 
 #define dout_subsys ceph_subsys_auth
 
-bool AuthNoneAuthorizeHandler::verify_authorizer(CephContext *cct, KeyStore *keys,
-						 bufferlist& authorizer_data, bufferlist& authorizer_reply,
-						 EntityName& entity_name, uint64_t& global_id, AuthCapsInfo& caps_info, CryptoKey& session_key,
-uint64_t *auid)
+bool AuthNoneAuthorizeHandler::verify_authorizer(
+  CephContext *cct, KeyStore *keys,
+  bufferlist& authorizer_data, bufferlist& authorizer_reply,
+  EntityName& entity_name, uint64_t& global_id, AuthCapsInfo& caps_info,
+  CryptoKey& session_key,
+  uint64_t *auid,
+  std::unique_ptr<AuthAuthorizerChallenge> *challenge)
 {
   auto iter = authorizer_data.cbegin();
 
diff --git a/src/auth/none/AuthNoneAuthorizeHandler.h b/src/auth/none/AuthNoneAuthorizeHandler.h
index b531cfb77360..0ce542bf678e 100644
--- a/src/auth/none/AuthNoneAuthorizeHandler.h
+++ b/src/auth/none/AuthNoneAuthorizeHandler.h
@@ -23,7 +23,8 @@ struct AuthNoneAuthorizeHandler : public AuthAuthorizeHandler {
   bool verify_authorizer(CephContext *cct, KeyStore *keys,
 			 bufferlist& authorizer_data, bufferlist& authorizer_reply,
                          EntityName& entity_name, uint64_t& global_id,
-			 AuthCapsInfo& caps_info, CryptoKey& session_key, uint64_t *auid=NULL) override;
+			 AuthCapsInfo& caps_info, CryptoKey& session_key, uint64_t *auid,
+			 std::unique_ptr<AuthAuthorizerChallenge> *challenge) override;
   int authorizer_session_crypto() override;
 };
 
diff --git a/src/auth/none/AuthNoneProtocol.h b/src/auth/none/AuthNoneProtocol.h
index 9664422a6c7e..64865355eae9 100644
--- a/src/auth/none/AuthNoneProtocol.h
+++ b/src/auth/none/AuthNoneProtocol.h
@@ -17,6 +17,8 @@
 
 #include "auth/Auth.h"
 
+class CephContext;
+
 struct AuthNoneAuthorizer : public AuthAuthorizer {
   AuthNoneAuthorizer() : AuthAuthorizer(CEPH_AUTH_NONE) { }
   bool build_authorizer(const EntityName &ename, uint64_t global_id) {
@@ -27,6 +29,7 @@ struct AuthNoneAuthorizer : public AuthAuthorizer {
     return 0;
   }
   bool verify_reply(bufferlist::const_iterator& reply) override { return true; }
+  bool add_challenge(CephContext *cct, bufferlist& ch) override { return true; }
 };
 
 #endif
diff --git a/src/auth/unknown/AuthUnknownAuthorizeHandler.cc b/src/auth/unknown/AuthUnknownAuthorizeHandler.cc
index 62cb638874e2..90e00ef579a5 100644
--- a/src/auth/unknown/AuthUnknownAuthorizeHandler.cc
+++ b/src/auth/unknown/AuthUnknownAuthorizeHandler.cc
@@ -14,10 +14,13 @@
 
 #include "AuthUnknownAuthorizeHandler.h"
 
-bool AuthUnknownAuthorizeHandler::verify_authorizer(CephContext *cct, KeyStore *keys,
-						 bufferlist& authorizer_data, bufferlist& authorizer_reply,
-						 EntityName& entity_name, uint64_t& global_id, AuthCapsInfo& caps_info, CryptoKey& session_key,
-uint64_t *auid)
+bool AuthUnknownAuthorizeHandler::verify_authorizer(
+  CephContext *cct, KeyStore *keys,
+  bufferlist& authorizer_data, bufferlist& authorizer_reply,
+  EntityName& entity_name, uint64_t& global_id, AuthCapsInfo& caps_info,
+  CryptoKey& session_key,
+  uint64_t *auid,
+  std::unique_ptr<AuthAuthorizerChallenge> *challenge)
 {
   // For unknown authorizers, there's nothing to verify.  They're "OK" by definition.  PLR
 
diff --git a/src/auth/unknown/AuthUnknownAuthorizeHandler.h b/src/auth/unknown/AuthUnknownAuthorizeHandler.h
index 9795ebfe9bf6..e052af5def7d 100644
--- a/src/auth/unknown/AuthUnknownAuthorizeHandler.h
+++ b/src/auth/unknown/AuthUnknownAuthorizeHandler.h
@@ -23,7 +23,8 @@ struct AuthUnknownAuthorizeHandler : public AuthAuthorizeHandler {
   bool verify_authorizer(CephContext *cct, KeyStore *keys,
 			 bufferlist& authorizer_data, bufferlist& authorizer_reply,
                          EntityName& entity_name, uint64_t& global_id,
-			 AuthCapsInfo& caps_info, CryptoKey& session_key, uint64_t *auid=NULL) override;
+			 AuthCapsInfo& caps_info, CryptoKey& session_key, uint64_t *auid,
+			 std::unique_ptr<AuthAuthorizerChallenge> *challenge) override;
   int authorizer_session_crypto() override;
 };
 
diff --git a/src/include/msgr.h b/src/include/msgr.h
index 1953eb28b40b..62582b0bca7b 100644
--- a/src/include/msgr.h
+++ b/src/include/msgr.h
@@ -93,7 +93,7 @@ struct ceph_entity_inst {
 #define CEPH_MSGR_TAG_SEQ           13 /* 64-bit int follows with seen seq number */
 #define CEPH_MSGR_TAG_KEEPALIVE2     14
 #define CEPH_MSGR_TAG_KEEPALIVE2_ACK 15  /* keepalive reply */
-
+#define CEPH_MSGR_TAG_CHALLENGE_AUTHORIZER 16  /* ceph v2 doing server challenge */
 
 /*
  * connection negotiation
diff --git a/src/mds/MDSDaemon.cc b/src/mds/MDSDaemon.cc
index 847a9ea716fb..d1021afb64d6 100644
--- a/src/mds/MDSDaemon.cc
+++ b/src/mds/MDSDaemon.cc
@@ -1295,7 +1295,8 @@ bool MDSDaemon::ms_handle_refused(Connection *con)
 
 bool MDSDaemon::ms_verify_authorizer(Connection *con, int peer_type,
 			       int protocol, bufferlist& authorizer_data, bufferlist& authorizer_reply,
-			       bool& is_valid, CryptoKey& session_key)
+				     bool& is_valid, CryptoKey& session_key,
+				     std::unique_ptr<AuthAuthorizerChallenge> *challenge)
 {
   Mutex::Locker l(mds_lock);
   if (stopping) {
@@ -1327,7 +1328,7 @@ bool MDSDaemon::ms_verify_authorizer(Connection *con, int peer_type,
     is_valid = authorize_handler->verify_authorizer(
       cct, keys,
       authorizer_data, authorizer_reply, name, global_id, caps_info,
-      session_key);
+      session_key, nullptr, challenge);
   } else {
     dout(10) << __func__ << " no rotating_keys (yet), denied" << dendl;
     is_valid = false;
diff --git a/src/mds/MDSDaemon.h b/src/mds/MDSDaemon.h
index b9d331971c9b..75cb176698a4 100644
--- a/src/mds/MDSDaemon.h
+++ b/src/mds/MDSDaemon.h
@@ -108,7 +108,8 @@ class MDSDaemon : public Dispatcher, public md_config_obs_t {
   bool ms_get_authorizer(int dest_type, AuthAuthorizer **authorizer, bool force_new) override;
   bool ms_verify_authorizer(Connection *con, int peer_type,
 			       int protocol, bufferlist& authorizer_data, bufferlist& authorizer_reply,
-			       bool& isvalid, CryptoKey& session_key) override;
+			    bool& isvalid, CryptoKey& session_key,
+			    std::unique_ptr<AuthAuthorizerChallenge> *challenge) override;
   void ms_handle_accept(Connection *con) override;
   void ms_handle_connect(Connection *con) override;
   bool ms_handle_reset(Connection *con) override;
diff --git a/src/mgr/DaemonServer.cc b/src/mgr/DaemonServer.cc
index 8337b34d90d1..322e7d6e3a89 100644
--- a/src/mgr/DaemonServer.cc
+++ b/src/mgr/DaemonServer.cc
@@ -144,13 +144,15 @@ entity_addr_t DaemonServer::get_myaddr() const
 }
 
 
-bool DaemonServer::ms_verify_authorizer(Connection *con,
-    int peer_type,
-    int protocol,
-    ceph::bufferlist& authorizer_data,
-    ceph::bufferlist& authorizer_reply,
-    bool& is_valid,
-    CryptoKey& session_key)
+bool DaemonServer::ms_verify_authorizer(
+  Connection *con,
+  int peer_type,
+  int protocol,
+  ceph::bufferlist& authorizer_data,
+  ceph::bufferlist& authorizer_reply,
+  bool& is_valid,
+  CryptoKey& session_key,
+  std::unique_ptr<AuthAuthorizerChallenge> *challenge)
 {
   AuthAuthorizeHandler *handler = nullptr;
   if (peer_type == CEPH_ENTITY_TYPE_OSD ||
@@ -178,7 +180,9 @@ bool DaemonServer::ms_verify_authorizer(Connection *con,
       authorizer_data,
       authorizer_reply, s->entity_name,
       s->global_id, caps_info,
-      session_key);
+      session_key,
+      nullptr,
+      challenge);
   } else {
     dout(10) << __func__ << " no rotating_keys (yet), denied" << dendl;
     is_valid = false;
diff --git a/src/mgr/DaemonServer.h b/src/mgr/DaemonServer.h
index 7972a1d84763..9fb4cca71d43 100644
--- a/src/mgr/DaemonServer.h
+++ b/src/mgr/DaemonServer.h
@@ -124,13 +124,15 @@ public:
   bool ms_handle_refused(Connection *con) override;
   bool ms_get_authorizer(int dest_type, AuthAuthorizer **authorizer,
                          bool force_new) override;
-  bool ms_verify_authorizer(Connection *con,
-      int peer_type,
-      int protocol,
-      ceph::bufferlist& authorizer,
-      ceph::bufferlist& authorizer_reply,
-      bool& isvalid,
-      CryptoKey& session_key) override;
+  bool ms_verify_authorizer(
+    Connection *con,
+    int peer_type,
+    int protocol,
+    ceph::bufferlist& authorizer,
+    ceph::bufferlist& authorizer_reply,
+    bool& isvalid,
+    CryptoKey& session_key,
+    std::unique_ptr<AuthAuthorizerChallenge> *challenge) override;
 
   bool handle_open(MMgrOpen *m);
   bool handle_close(MMgrClose *m);
diff --git a/src/mon/Monitor.cc b/src/mon/Monitor.cc
index a8ecb2eebf4b..9d31e19031b3 100644
--- a/src/mon/Monitor.cc
+++ b/src/mon/Monitor.cc
@@ -5780,7 +5780,8 @@ bool Monitor::ms_get_authorizer(int service_id, AuthAuthorizer **authorizer,
 bool Monitor::ms_verify_authorizer(Connection *con, int peer_type,
 				   int protocol, bufferlist& authorizer_data,
 				   bufferlist& authorizer_reply,
-				   bool& isvalid, CryptoKey& session_key)
+				   bool& isvalid, CryptoKey& session_key,
+				   std::unique_ptr<AuthAuthorizerChallenge> *challenge)
 {
   dout(10) << "ms_verify_authorizer " << con->get_peer_addr()
 	   << " " << ceph_entity_type_name(peer_type)
@@ -5799,7 +5800,7 @@ bool Monitor::ms_verify_authorizer(Connection *con, int peer_type,
       
       if (authorizer_data.length()) {
 	bool ret = cephx_verify_authorizer(g_ceph_context, &keyring, iter,
-					  auth_ticket_info, authorizer_reply);
+					   auth_ticket_info, challenge, authorizer_reply);
 	if (ret) {
 	  session_key = auth_ticket_info.session_key;
 	  isvalid = true;
diff --git a/src/mon/Monitor.h b/src/mon/Monitor.h
index 1acf69cc31a8..d4b11830e42c 100644
--- a/src/mon/Monitor.h
+++ b/src/mon/Monitor.h
@@ -887,7 +887,8 @@ public:
   bool ms_get_authorizer(int dest_type, AuthAuthorizer **authorizer, bool force_new) override;
   bool ms_verify_authorizer(Connection *con, int peer_type,
 			    int protocol, bufferlist& authorizer_data, bufferlist& authorizer_reply,
-			    bool& isvalid, CryptoKey& session_key) override;
+			    bool& isvalid, CryptoKey& session_key,
+			    std::unique_ptr<AuthAuthorizerChallenge> *challenge) override;
   bool ms_handle_reset(Connection *con) override;
   void ms_handle_remote_reset(Connection *con) override {}
   bool ms_handle_refused(Connection *con) override;
diff --git a/src/msg/Dispatcher.h b/src/msg/Dispatcher.h
index 774ca405134a..faab248d60ff 100644
--- a/src/msg/Dispatcher.h
+++ b/src/msg/Dispatcher.h
@@ -16,6 +16,7 @@
 #ifndef CEPH_DISPATCHER_H
 #define CEPH_DISPATCHER_H
 
+#include <memory>
 #include "include/buffer_fwd.h"
 #include "include/assert.h"
 
@@ -25,6 +26,7 @@ class Connection;
 class AuthAuthorizer;
 class CryptoKey;
 class CephContext;
+class AuthAuthorizerChallenge;
 
 class Dispatcher {
 public:
@@ -203,7 +205,10 @@ public:
 				    ceph::bufferlist& authorizer,
 				    ceph::bufferlist& authorizer_reply,
 				    bool& isvalid,
-				    CryptoKey& session_key) { return false; }
+				    CryptoKey& session_key,
+				    std::unique_ptr<AuthAuthorizerChallenge> *challenge) {
+    return false;
+  }
   /**
    * @} //Authentication
    */
diff --git a/src/msg/Messenger.h b/src/msg/Messenger.h
index eb3541780364..1feb0adc016e 100644
--- a/src/msg/Messenger.h
+++ b/src/msg/Messenger.h
@@ -805,11 +805,13 @@ public:
    */
   bool ms_deliver_verify_authorizer(Connection *con, int peer_type,
 				    int protocol, bufferlist& authorizer, bufferlist& authorizer_reply,
-				    bool& isvalid, CryptoKey& session_key) {
+				    bool& isvalid, CryptoKey& session_key,
+				    std::unique_ptr<AuthAuthorizerChallenge> *challenge) {
     for (list<Dispatcher*>::iterator p = dispatchers.begin();
 	 p != dispatchers.end();
 	 ++p) {
-      if ((*p)->ms_verify_authorizer(con, peer_type, protocol, authorizer, authorizer_reply, isvalid, session_key))
+      if ((*p)->ms_verify_authorizer(con, peer_type, protocol, authorizer, authorizer_reply,
+				     isvalid, session_key, challenge))
 	return true;
     }
     return false;
diff --git a/src/msg/async/AsyncConnection.cc b/src/msg/async/AsyncConnection.cc
index 4036fba9b9ad..77955af23fa1 100644
--- a/src/msg/async/AsyncConnection.cc
+++ b/src/msg/async/AsyncConnection.cc
@@ -128,7 +128,8 @@ AsyncConnection::AsyncConnection(CephContext *cct, AsyncMessenger *m, DispatchQu
     recv_start(0), recv_end(0),
     last_active(ceph::coarse_mono_clock::now()),
     inactive_timeout_us(cct->_conf->ms_tcp_read_timeout*1000*1000),
-    msg_left(0), cur_msg_size(0), got_bad_auth(false), authorizer(NULL), replacing(false),
+    msg_left(0), cur_msg_size(0), got_bad_auth(false),
+    authorizer(NULL), replacing(false),
     is_reset_from_peer(false), once_ready(false), state_buffer(NULL), state_offset(0),
     worker(w), center(&w->center)
 {
@@ -1010,8 +1011,7 @@ ssize_t AsyncConnection::_process_connection()
 
     case STATE_CONNECTING_SEND_CONNECT_MSG:
       {
-        if (!got_bad_auth) {
-          delete authorizer;
+        if (!authorizer) {
           authorizer = async_msgr->get_authorizer(peer_type, false);
         }
         bufferlist bl;
@@ -1091,6 +1091,14 @@ ssize_t AsyncConnection::_process_connection()
           }
 
           authorizer_reply.append(state_buffer, connect_reply.authorizer_len);
+
+	  if (connect_reply.tag == CEPH_MSGR_TAG_CHALLENGE_AUTHORIZER) {
+	    ldout(async_msgr->cct,10) << __func__ << " connect got auth challenge" << dendl;
+	    authorizer->add_challenge(async_msgr->cct, authorizer_reply);
+	    state = STATE_CONNECTING_SEND_CONNECT_MSG;
+	    break;
+	  }
+
           auto iter = authorizer_reply.cbegin();
           if (authorizer && !authorizer->verify_reply(iter)) {
             ldout(async_msgr->cct, 0) << __func__ << " failed verifying authorize reply" << dendl;
@@ -1508,12 +1516,26 @@ ssize_t AsyncConnection::handle_connect_msg(ceph_msg_connect &connect, bufferlis
   lock.unlock();
 
   bool authorizer_valid;
-  if (!async_msgr->verify_authorizer(this, peer_type, connect.authorizer_protocol, authorizer_bl,
-                               authorizer_reply, authorizer_valid, session_key) || !authorizer_valid) {
+  bool need_challenge = HAVE_FEATURE(connect.features, CEPHX_V2);
+  bool had_challenge = (bool)authorizer_challenge;
+  if (!async_msgr->verify_authorizer(
+	this, peer_type, connect.authorizer_protocol, authorizer_bl,
+	authorizer_reply, authorizer_valid, session_key,
+	need_challenge ? &authorizer_challenge : nullptr) ||
+      !authorizer_valid) {
     lock.lock();
-    ldout(async_msgr->cct,0) << __func__ << ": got bad authorizer" << dendl;
+    char tag;
+    if (need_challenge && !had_challenge && authorizer_challenge) {
+      ldout(async_msgr->cct,0) << __func__ << ": challenging authorizer"
+			       << dendl;
+      assert(authorizer_reply.length());
+      tag = CEPH_MSGR_TAG_CHALLENGE_AUTHORIZER;
+    } else {
+      ldout(async_msgr->cct,0) << __func__ << ": got bad authorizer" << dendl;
+      tag = CEPH_MSGR_TAG_BADAUTHORIZER;
+    }
     session_security.reset();
-    return _reply_accept(CEPH_MSGR_TAG_BADAUTHORIZER, connect, reply, authorizer_reply);
+    return _reply_accept(tag, connect, reply, authorizer_reply);
   }
 
   // We've verified the authorizer for this AsyncConnection, so set up the session security structure.  PLR
@@ -1711,6 +1733,8 @@ ssize_t AsyncConnection::handle_connect_msg(ceph_msg_connect &connect, bufferlis
     // there shouldn't exist any buffer
     assert(recv_start == recv_end);
 
+    existing->authorizer_challenge.reset();
+
     auto deactivate_existing = std::bind(
         [existing, new_worker, new_center, connect, reply, authorizer_reply](ConnectedSocket &cs) mutable {
       // we need to delete time event in original thread
diff --git a/src/msg/async/AsyncConnection.h b/src/msg/async/AsyncConnection.h
index 0a3da9ddccac..a8455853bf36 100644
--- a/src/msg/async/AsyncConnection.h
+++ b/src/msg/async/AsyncConnection.h
@@ -368,6 +368,7 @@ class AsyncConnection : public Connection {
   Worker *worker;
   EventCenter *center;
   ceph::shared_ptr<AuthSessionHandler> session_security;
+  std::unique_ptr<AuthAuthorizerChallenge> authorizer_challenge; // accept side
 
  public:
   // used by eventcallback
diff --git a/src/msg/async/AsyncMessenger.h b/src/msg/async/AsyncMessenger.h
index a07ed4c69c3b..64f2e610ab7f 100644
--- a/src/msg/async/AsyncMessenger.h
+++ b/src/msg/async/AsyncMessenger.h
@@ -383,9 +383,10 @@ public:
    * This wraps ms_deliver_verify_authorizer; we use it for AsyncConnection.
    */
   bool verify_authorizer(Connection *con, int peer_type, int protocol, bufferlist& auth, bufferlist& auth_reply,
-                         bool& isvalid, CryptoKey& session_key) {
+                         bool& isvalid, CryptoKey& session_key,
+			 std::unique_ptr<AuthAuthorizerChallenge> *challenge) {
     return ms_deliver_verify_authorizer(con, peer_type, protocol, auth,
-                                        auth_reply, isvalid, session_key);
+                                        auth_reply, isvalid, session_key, challenge);
   }
   /**
    * Increment the global sequence for this AsyncMessenger and return it.
diff --git a/src/msg/simple/Pipe.cc b/src/msg/simple/Pipe.cc
index ff35b038bd53..6ae12eef896f 100644
--- a/src/msg/simple/Pipe.cc
+++ b/src/msg/simple/Pipe.cc
@@ -351,6 +351,10 @@ int Pipe::accept()
   // used for reading in the remote acked seq on connect
   uint64_t newly_acked_seq = 0;
 
+  bool need_challenge = false;
+  bool had_challenge = false;
+  std::unique_ptr<AuthAuthorizerChallenge> authorizer_challenge;
+
   recv_reset();
 
   set_socket_options();
@@ -515,14 +519,27 @@ int Pipe::accept()
 
     pipe_lock.Unlock();
 
-    if (!msgr->verify_authorizer(connection_state.get(), peer_type, connect.authorizer_protocol, authorizer,
-				 authorizer_reply, authorizer_valid, session_key) ||
+    need_challenge = HAVE_FEATURE(connect.features, CEPHX_V2);
+    had_challenge = (bool)authorizer_challenge;
+    authorizer_reply.clear();
+    if (!msgr->verify_authorizer(
+	  connection_state.get(), peer_type, connect.authorizer_protocol, authorizer,
+	  authorizer_reply, authorizer_valid, session_key,
+	  need_challenge ? &authorizer_challenge : nullptr) ||
 	!authorizer_valid) {
-      ldout(msgr->cct,0) << "accept: got bad authorizer" << dendl;
       pipe_lock.Lock();
       if (state != STATE_ACCEPTING)
 	goto shutting_down_msgr_unlocked;
-      reply.tag = CEPH_MSGR_TAG_BADAUTHORIZER;
+      if (!had_challenge && need_challenge && authorizer_challenge) {
+	ldout(msgr->cct,0) << "accept: challenging authorizer "
+			   << authorizer_reply.length()
+			   << " bytes" << dendl;
+	assert(authorizer_reply.length());
+	reply.tag = CEPH_MSGR_TAG_CHALLENGE_AUTHORIZER;
+      } else {
+	ldout(msgr->cct,0) << "accept: got bad authorizer" << dendl;
+	reply.tag = CEPH_MSGR_TAG_BADAUTHORIZER;
+      }
       session_security.reset();
       goto reply;
     } 
@@ -1128,8 +1145,9 @@ int Pipe::connect()
 
 
   while (1) {
-    delete authorizer;
-    authorizer = msgr->get_authorizer(peer_type, false);
+    if (!authorizer) {
+      authorizer = msgr->get_authorizer(peer_type, false);
+    }
     bufferlist authorizer_reply;
 
     ceph_msg_connect connect;
@@ -1196,6 +1214,13 @@ int Pipe::connect()
       authorizer_reply.push_back(bp);
     }
 
+    if (reply.tag == CEPH_MSGR_TAG_CHALLENGE_AUTHORIZER) {
+      authorizer->add_challenge(msgr->cct, authorizer_reply);
+      ldout(msgr->cct,10) << " got authorizer challenge, " << authorizer_reply.length()
+			  << " bytes" << dendl;
+      continue;
+    }
+
     if (authorizer) {
       auto iter = authorizer_reply.cbegin();
       if (!authorizer->verify_reply(iter)) {
diff --git a/src/msg/simple/SimpleMessenger.cc b/src/msg/simple/SimpleMessenger.cc
index 4918c52a7af4..18fbd7e218c7 100644
--- a/src/msg/simple/SimpleMessenger.cc
+++ b/src/msg/simple/SimpleMessenger.cc
@@ -413,9 +413,12 @@ AuthAuthorizer *SimpleMessenger::get_authorizer(int peer_type, bool force_new)
 
 bool SimpleMessenger::verify_authorizer(Connection *con, int peer_type,
 					int protocol, bufferlist& authorizer, bufferlist& authorizer_reply,
-					bool& isvalid,CryptoKey& session_key)
+					bool& isvalid,CryptoKey& session_key,
+					std::unique_ptr<AuthAuthorizerChallenge> *challenge)
 {
-  return ms_deliver_verify_authorizer(con, peer_type, protocol, authorizer, authorizer_reply, isvalid,session_key);
+  return ms_deliver_verify_authorizer(con, peer_type, protocol, authorizer, authorizer_reply,
+				      isvalid, session_key,
+				      challenge);
 }
 
 ConnectionRef SimpleMessenger::get_connection(const entity_inst_t& dest)
diff --git a/src/msg/simple/SimpleMessenger.h b/src/msg/simple/SimpleMessenger.h
index 93597a70a5b8..cbde2207655e 100644
--- a/src/msg/simple/SimpleMessenger.h
+++ b/src/msg/simple/SimpleMessenger.h
@@ -347,8 +347,10 @@ public:
   /**
    * This wraps ms_deliver_verify_authorizer; we use it for Pipe.
    */
-  bool verify_authorizer(Connection *con, int peer_type, int protocol, bufferlist& auth, bufferlist& auth_reply,
-                         bool& isvalid,CryptoKey& session_key);
+  bool verify_authorizer(Connection *con, int peer_type, int protocol, bufferlist& auth,
+			 bufferlist& auth_reply,
+                         bool& isvalid,CryptoKey& session_key,
+			 std::unique_ptr<AuthAuthorizerChallenge> *challenge);
   /**
    * Increment the global sequence for this SimpleMessenger and return it.
    * This is for the connect protocol, although it doesn't hurt if somebody
diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc
index 53318b2663d9..a9a2f42f891b 100644
--- a/src/osd/OSD.cc
+++ b/src/osd/OSD.cc
@@ -6539,9 +6539,11 @@ bool OSD::ms_get_authorizer(int dest_type, AuthAuthorizer **authorizer, bool for
 }
 
 
-bool OSD::ms_verify_authorizer(Connection *con, int peer_type,
-			       int protocol, bufferlist& authorizer_data, bufferlist& authorizer_reply,
-			       bool& isvalid, CryptoKey& session_key)
+bool OSD::ms_verify_authorizer(
+  Connection *con, int peer_type,
+  int protocol, bufferlist& authorizer_data, bufferlist& authorizer_reply,
+  bool& isvalid, CryptoKey& session_key,
+  std::unique_ptr<AuthAuthorizerChallenge> *challenge)
 {
   AuthAuthorizeHandler *authorize_handler = 0;
   switch (peer_type) {
@@ -6573,7 +6575,7 @@ bool OSD::ms_verify_authorizer(Connection *con, int peer_type,
     isvalid = authorize_handler->verify_authorizer(
       cct, keys,
       authorizer_data, authorizer_reply, name, global_id, caps_info, session_key,
-      &auid);
+      &auid, challenge);
   } else {
     dout(10) << __func__ << " no rotating_keys (yet), denied" << dendl;
     isvalid = false;
diff --git a/src/osd/OSD.h b/src/osd/OSD.h
index 0ebe5ecd2eb8..17988685f7a9 100644
--- a/src/osd/OSD.h
+++ b/src/osd/OSD.h
@@ -1622,7 +1622,8 @@ public:
     }
     bool ms_verify_authorizer(Connection *con, int peer_type,
 			      int protocol, bufferlist& authorizer_data, bufferlist& authorizer_reply,
-			      bool& isvalid, CryptoKey& session_key) override {
+			      bool& isvalid, CryptoKey& session_key,
+			      std::unique_ptr<AuthAuthorizerChallenge> *challenge) override {
       isvalid = true;
       return true;
     }
@@ -2130,7 +2131,8 @@ private:
   bool ms_get_authorizer(int dest_type, AuthAuthorizer **authorizer, bool force_new) override;
   bool ms_verify_authorizer(Connection *con, int peer_type,
 			    int protocol, bufferlist& authorizer, bufferlist& authorizer_reply,
-			    bool& isvalid, CryptoKey& session_key) override;
+			    bool& isvalid, CryptoKey& session_key,
+			    std::unique_ptr<AuthAuthorizerChallenge> *challenge) override;
   void ms_handle_connect(Connection *con) override;
   void ms_handle_fast_connect(Connection *con) override;
   void ms_handle_fast_accept(Connection *con) override;
diff --git a/src/test/messenger/simple_dispatcher.h b/src/test/messenger/simple_dispatcher.h
index c5345d662d1a..8b84ff4b6d2f 100644
--- a/src/test/messenger/simple_dispatcher.h
+++ b/src/test/messenger/simple_dispatcher.h
@@ -113,9 +113,10 @@ public:
    * authorizer, false otherwise.
    */
   bool ms_verify_authorizer(Connection *con, int peer_type,
-				    int protocol, bufferlist& authorizer,
-				    bufferlist& authorizer_reply,
-				    bool& isvalid, CryptoKey& session_key) override {
+			    int protocol, bufferlist& authorizer,
+			    bufferlist& authorizer_reply,
+			    bool& isvalid, CryptoKey& session_key,
+			    std::unique_ptr<AuthAuthorizerChallenge> *challenge) override {
     /* always succeed */
     isvalid = true;
     return true;
diff --git a/src/test/messenger/xio_dispatcher.h b/src/test/messenger/xio_dispatcher.h
index 3b59108071fb..495fa3a75216 100644
--- a/src/test/messenger/xio_dispatcher.h
+++ b/src/test/messenger/xio_dispatcher.h
@@ -115,7 +115,8 @@ public:
   virtual bool ms_verify_authorizer(Connection *con, int peer_type,
 				    int protocol, bufferlist& authorizer,
 				    bufferlist& authorizer_reply,
-				    bool& isvalid, CryptoKey& session_key) {
+				    bool& isvalid, CryptoKey& session_key,
+				    std::unique_ptr<AuthAuthorizerChallenge> *challenge) {
     /* always succeed */
     isvalid = true;
     return true;
diff --git a/src/test/msgr/perf_msgr_client.cc b/src/test/msgr/perf_msgr_client.cc
index b7c66ea79387..1442b05784a5 100644
--- a/src/test/msgr/perf_msgr_client.cc
+++ b/src/test/msgr/perf_msgr_client.cc
@@ -58,7 +58,8 @@ class MessengerClient {
     bool ms_handle_refused(Connection *con) override { return false; }
     bool ms_verify_authorizer(Connection *con, int peer_type, int protocol,
                               bufferlist& authorizer, bufferlist& authorizer_reply,
-                              bool& isvalid, CryptoKey& session_key) override {
+                              bool& isvalid, CryptoKey& session_key,
+			      std::unique_ptr<AuthAuthorizerChallenge> *challenge) override {
       isvalid = true;
       return true;
     }
diff --git a/src/test/msgr/perf_msgr_server.cc b/src/test/msgr/perf_msgr_server.cc
index 87ebb6116aaa..7df732853daf 100644
--- a/src/test/msgr/perf_msgr_server.cc
+++ b/src/test/msgr/perf_msgr_server.cc
@@ -100,7 +100,8 @@ class ServerDispatcher : public Dispatcher {
   }
   bool ms_verify_authorizer(Connection *con, int peer_type, int protocol,
                             bufferlist& authorizer, bufferlist& authorizer_reply,
-                            bool& isvalid, CryptoKey& session_key) override {
+                            bool& isvalid, CryptoKey& session_key,
+			    std::unique_ptr<AuthAuthorizerChallenge> *challenge) override {
     isvalid = true;
     return true;
   }
diff --git a/src/test/msgr/test_msgr.cc b/src/test/msgr/test_msgr.cc
index a027aa6fcc9a..07887717b39c 100644
--- a/src/test/msgr/test_msgr.cc
+++ b/src/test/msgr/test_msgr.cc
@@ -203,7 +203,8 @@ class FakeDispatcher : public Dispatcher {
 
   bool ms_verify_authorizer(Connection *con, int peer_type, int protocol,
                             bufferlist& authorizer, bufferlist& authorizer_reply,
-                            bool& isvalid, CryptoKey& session_key) override {
+                            bool& isvalid, CryptoKey& session_key,
+			    std::unique_ptr<AuthAuthorizerChallenge> *challenge) override {
     isvalid = true;
     return true;
   }
@@ -893,7 +894,8 @@ class SyntheticDispatcher : public Dispatcher {
 
   bool ms_verify_authorizer(Connection *con, int peer_type, int protocol,
                             bufferlist& authorizer, bufferlist& authorizer_reply,
-                            bool& isvalid, CryptoKey& session_key) override {
+                            bool& isvalid, CryptoKey& session_key,
+			    std::unique_ptr<AuthAuthorizerChallenge> *challenge) override {
     isvalid = true;
     return true;
   }
@@ -1436,7 +1438,8 @@ class MarkdownDispatcher : public Dispatcher {
   }
   bool ms_verify_authorizer(Connection *con, int peer_type, int protocol,
                             bufferlist& authorizer, bufferlist& authorizer_reply,
-                            bool& isvalid, CryptoKey& session_key) override {
+                            bool& isvalid, CryptoKey& session_key,
+			    std::unique_ptr<AuthAuthorizerChallenge> *challenge) override {
     isvalid = true;
     return true;
   }