crypto/cmp/,apps/lib/cmp_mock_srv.c: add delayed delivery for all types of responses

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
(Merged from https://github.com/openssl/openssl/pull/20727)

6 files changed, 317 insertions, 80 deletions

diff --git a/crypto/cmp/cmp_client.c b/crypto/cmp/cmp_client.c
index b5b0557b0d..cf352c9d71 100644
--- a/crypto/cmp/cmp_client.c
+++ b/crypto/cmp/cmp_client.c
@@ -113,6 +113,23 @@ static int save_statusInfo(OSSL_CMP_CTX *ctx, OSSL_CMP_PKISI *si)
     return 1;
 }
 
+static int is_crep_with_waiting(OSSL_CMP_MSG *resp, int rid)
+{
+    OSSL_CMP_CERTREPMESSAGE *crepmsg;
+    OSSL_CMP_CERTRESPONSE *crep;
+    int bt = OSSL_CMP_MSG_get_bodytype(resp);
+
+    if (!IS_CREP(bt))
+        return 0;
+
+    crepmsg = resp->body->value.ip; /* same for cp and kup */
+    crep = ossl_cmp_certrepmessage_get0_certresponse(crepmsg, rid);
+
+    return (crep != NULL
+            && ossl_cmp_pkisi_get_status(crep->status)
+            == OSSL_CMP_PKISTATUS_waiting);
+}
+
 /*-
  * Perform the generic aspects of sending a request and receiving a response.
  * Returns 1 on success and provides the received PKIMESSAGE in *rep.
@@ -180,7 +197,8 @@ static int send_receive_check(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *req,
      * Still we use this preliminary value already for a progress report because
      * the following msg verification may also produce log entries and may fail.
      */
-    ossl_cmp_log1(INFO, ctx, "received %s", ossl_cmp_bodytype_to_string(bt));
+    ossl_cmp_log2(INFO, ctx, "received %s%s", ossl_cmp_bodytype_to_string(bt),
+                  ossl_cmp_is_error_with_waiting(*rep) ? " (waiting)" : "");
 
     /* copy received extraCerts to ctx->extraCertsIn so they can be retrieved */
     if (bt != OSSL_CMP_PKIBODY_POLLREP && bt != OSSL_CMP_PKIBODY_PKICONF
@@ -191,9 +209,17 @@ static int send_receive_check(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *req,
                                    expected_type))
         return 0;
 
+    /*
+     * 'rep' can have the expected response type, which during polling is
+     * pollRep. When polling, also any other non-error response (the final
+     * response) is fine here. When not yet polling, delayed delivery may
+     * be started by an error with 'waiting' status (while it may also be
+     * started by an expected response type ip/cp/kup).
+     */
     if (bt == expected_type
-        /* as an answer to polling, there could be IP/CP/KUP: */
-            || (IS_CREP(bt) && expected_type == OSSL_CMP_PKIBODY_POLLREP))
+        || (expected_type == OSSL_CMP_PKIBODY_POLLREP
+            ? bt != OSSL_CMP_PKIBODY_ERROR
+            : ossl_cmp_is_error_with_waiting(*rep)))
         return 1;
 
     /* received message type is not one of the expected ones (e.g., error) */
@@ -235,7 +261,7 @@ static int send_receive_check(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *req,
 
 /*-
  * When a 'waiting' PKIStatus has been received, this function is used to
- * poll, which should yield a pollRep or finally a CertRepMessage in ip/cp/kup.
+ * poll, which should yield a pollRep or the final response.
  * On receiving a pollRep, which includes a checkAfter value, it return this
  * value if sleep == 0, else it sleeps as long as indicated and retries.
  *
@@ -246,7 +272,8 @@ static int send_receive_check(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *req,
  * Returns -1 on receiving pollRep if sleep == 0, setting the checkAfter value.
  * Returns 1 on success and provides the received PKIMESSAGE in *rep.
  *           In this case the caller is responsible for freeing *rep.
- * Returns 0 on error (which includes the case that timeout has been reached).
+ * Returns 0 on error (which includes the case that timeout has been reached or
+ *           received response with waiting status).
  */
 static int poll_for_response(OSSL_CMP_CTX *ctx, int sleep, int rid,
                              OSSL_CMP_MSG **rep, int *checkAfter)
@@ -312,7 +339,7 @@ static int poll_for_response(OSSL_CMP_CTX *ctx, int sleep, int rid,
                           str, check_after);
 
             if (ctx->total_timeout != 0) { /* timeout is not infinite */
-                const int exp = 5; /* expected max time per msg round trip */
+                const int exp = OSSL_CMP_EXPECTED_RESP_TIME;
                 int64_t time_left = (int64_t)(ctx->end_time - exp - time(NULL));
 
                 if (time_left <= 0) {
@@ -335,9 +362,19 @@ static int poll_for_response(OSSL_CMP_CTX *ctx, int sleep, int rid,
                     *checkAfter = (int)check_after;
                 return -1; /* exits the loop */
             }
+        } else if (is_crep_with_waiting(prep, rid)
+                   || ossl_cmp_is_error_with_waiting(prep)) {
+            /* status cannot be 'waiting' at this point */
+            (void)ossl_cmp_exchange_error(ctx, OSSL_CMP_PKISTATUS_rejection,
+                                          OSSL_CMP_CTX_FAILINFO_badRequest,
+                                          "polling already started",
+                                          0 /* errorCode */, NULL);
+            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKISTATUS);
+            goto err;
         } else {
-            ossl_cmp_info(ctx, "received ip/cp/kup after polling");
-            /* any other body type has been rejected by send_receive_check() */
+            ossl_cmp_info(ctx, "received final response after polling");
+            if (!ossl_cmp_ctx_set1_first_senderNonce(ctx, NULL))
+                return 0;
             break;
         }
     }
@@ -349,11 +386,66 @@ static int poll_for_response(OSSL_CMP_CTX *ctx, int sleep, int rid,
 
     return 1;
  err:
+    (void)ossl_cmp_ctx_set1_first_senderNonce(ctx, NULL);
     OSSL_CMP_MSG_free(preq);
     OSSL_CMP_MSG_free(prep);
     return 0;
 }
 
+static int save_senderNonce_if_waiting(OSSL_CMP_CTX *ctx,
+                                       OSSL_CMP_MSG *rep, int rid)
+{
+    /*
+     * LWCMP section 4.4 states: the senderNonce of the preceding request
+     * message because this value will be needed for checking the recipNonce
+     * of the final response to be received after polling.
+     */
+    if ((is_crep_with_waiting(rep, rid)
+         || ossl_cmp_is_error_with_waiting(rep))
+        && !ossl_cmp_ctx_set1_first_senderNonce(ctx, ctx->senderNonce))
+        return 0;
+
+    return 1;
+}
+
+/*
+ * send request and get response possibly with polling initiated by error msg.
+ * Polling for ip/cp/kup/ with 'waiting' status is handled elsewhere.
+ */
+static int send_receive_also_delayed(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *req,
+                                     OSSL_CMP_MSG **rep, int expected_type)
+{
+
+    if (!send_receive_check(ctx, req, rep, expected_type))
+        return 0;
+
+    if (ossl_cmp_is_error_with_waiting(*rep)) {
+        if (!save_senderNonce_if_waiting(ctx, *rep, -1 /* rid */))
+            return 0;
+        /*
+         * not modifying ctx->status during the certConf & error exchange,
+         * because these additional exchanges should not change the status.
+         */
+        if (expected_type != OSSL_CMP_PKIBODY_PKICONF
+            && !save_statusInfo(ctx, (*rep)->body->value.error->pKIStatusInfo))
+            return 0;
+
+        OSSL_CMP_MSG_free(*rep);
+        *rep = NULL;
+
+        if (poll_for_response(ctx, 1 /* can sleep */, -1 /* rid */,
+                              rep, NULL /* checkAfter */) <= 0) {
+            ERR_raise(ERR_LIB_CMP, CMP_R_POLLING_FAILED);
+            return 0;
+        }
+    }
+    if (OSSL_CMP_MSG_get_bodytype(*rep) != expected_type) {
+        ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
+        return 0;
+    }
+
+    return 1;
+}
 /*
  * Send certConf for IR, CR or KUR sequences and check response,
  * not modifying ctx->status during the certConf exchange
@@ -370,7 +462,8 @@ int ossl_cmp_exchange_certConf(OSSL_CMP_CTX *ctx, int certReqId,
     if (certConf == NULL)
         goto err;
 
-    res = send_receive_check(ctx, certConf, &PKIconf, OSSL_CMP_PKIBODY_PKICONF);
+    res = send_receive_also_delayed(ctx, certConf,
+                                    &PKIconf, OSSL_CMP_PKIBODY_PKICONF);
 
  err:
     OSSL_CMP_MSG_free(certConf);
@@ -394,7 +487,8 @@ int ossl_cmp_exchange_error(OSSL_CMP_CTX *ctx, int status, int fail_info,
     if ((error = ossl_cmp_error_new(ctx, si, errorCode, details, 0)) == NULL)
         goto err;
 
-    res = send_receive_check(ctx, error, &PKIconf, OSSL_CMP_PKIBODY_PKICONF);
+    res = send_receive_also_delayed(ctx, error,
+                                    &PKIconf, OSSL_CMP_PKIBODY_PKICONF);
 
  err:
     OSSL_CMP_MSG_free(error);
@@ -515,7 +609,7 @@ int OSSL_CMP_certConf_cb(OSSL_CMP_CTX *ctx, X509 *cert, int fail_info,
         if (X509_verify_cert(csc) <= 0)
             goto err;
 
-        if (!ossl_x509_add_certs_new(&chain,  X509_STORE_CTX_get0_chain(csc),
+        if (!ossl_x509_add_certs_new(&chain, X509_STORE_CTX_get0_chain(csc),
                                      X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
                                      | X509_ADD_FLAG_NO_SS)) {
             sk_X509_free(chain);
@@ -564,48 +658,74 @@ static int cert_response(OSSL_CMP_CTX *ctx, int sleep, int rid,
     EVP_PKEY *rkey = ossl_cmp_ctx_get0_newPubkey(ctx);
     int fail_info = 0; /* no failure */
     const char *txt = NULL;
-    OSSL_CMP_CERTREPMESSAGE *crepmsg;
-    OSSL_CMP_CERTRESPONSE *crep;
+    OSSL_CMP_CERTREPMESSAGE *crepmsg = NULL;
+    OSSL_CMP_CERTRESPONSE *crep = NULL;
     OSSL_CMP_certConf_cb_t cb;
     X509 *cert;
     char *subj = NULL;
     int ret = 1;
+    int rcvd_type;
+    OSSL_CMP_PKISI *si;
 
     if (!ossl_assert(ctx != NULL))
         return 0;
 
  retry:
-    crepmsg = (*resp)->body->value.ip; /* same for cp and kup */
-    if (sk_OSSL_CMP_CERTRESPONSE_num(crepmsg->response) > 1) {
-        ERR_raise(ERR_LIB_CMP, CMP_R_MULTIPLE_RESPONSES_NOT_SUPPORTED);
-        return 0;
-    }
-    crep = ossl_cmp_certrepmessage_get0_certresponse(crepmsg, rid);
-    if (crep == NULL)
-        return 0;
-    if (!save_statusInfo(ctx, crep->status))
-        return 0;
-    if (rid == OSSL_CMP_CERTREQID_NONE) { /* used for OSSL_CMP_PKIBODY_P10CR */
-        rid = ossl_cmp_asn1_get_int(crep->certReqId);
-        if (rid < OSSL_CMP_CERTREQID_NONE) {
-            ERR_raise(ERR_LIB_CMP, CMP_R_BAD_REQUEST_ID);
+    rcvd_type = OSSL_CMP_MSG_get_bodytype(*resp);
+    if (IS_CREP(rcvd_type)) {
+        crepmsg = (*resp)->body->value.ip; /* same for cp and kup */
+        if (sk_OSSL_CMP_CERTRESPONSE_num(crepmsg->response) > 1) {
+            ERR_raise(ERR_LIB_CMP, CMP_R_MULTIPLE_RESPONSES_NOT_SUPPORTED);
             return 0;
         }
+        crep = ossl_cmp_certrepmessage_get0_certresponse(crepmsg, rid);
+        if (crep == NULL)
+            return 0;
+        si = crep->status;
+
+        if (rid ==  OSSL_CMP_CERTREQID_NONE) {
+            /* for OSSL_CMP_PKIBODY_P10CR learn CertReqId from response */
+            rid = ossl_cmp_asn1_get_int(crep->certReqId);
+            if (rid ==  OSSL_CMP_CERTREQID_NONE) {
+                ERR_raise(ERR_LIB_CMP, CMP_R_BAD_REQUEST_ID);
+                return 0;
+            }
+        }
+    } else if (rcvd_type == OSSL_CMP_PKIBODY_ERROR) {
+        si = (*resp)->body->value.error->pKIStatusInfo;
+    } else {
+        ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
+        return 0;
     }
 
-    if (ossl_cmp_pkisi_get_status(crep->status) == OSSL_CMP_PKISTATUS_waiting) {
+    if (!save_statusInfo(ctx, si))
+        return 0;
+
+    if (ossl_cmp_pkisi_get_status(si) == OSSL_CMP_PKISTATUS_waiting) {
+        /* here we allow different flavor of ip/cp/kup & error with waiting */
         OSSL_CMP_MSG_free(*resp);
         *resp = NULL;
         if ((ret = poll_for_response(ctx, sleep, rid, resp, checkAfter)) != 0) {
             if (ret == -1) /* at this point implies sleep == 0 */
                 return ret; /* waiting */
-            goto retry; /* got ip/cp/kup, which may still indicate 'waiting' */
+            goto retry; /* got some response other than pollRep */
         } else {
             ERR_raise(ERR_LIB_CMP, CMP_R_POLLING_FAILED);
             return 0;
         }
     }
 
+    /* at this point, ip/cp/kup or error without waiting */
+    if (rcvd_type == OSSL_CMP_PKIBODY_ERROR) {
+        ERR_raise(ERR_LIB_CMP, CMP_R_RECEIVED_ERROR);
+        return 0;
+    }
+    /* here we are strict on the flavor of ip/cp/kup */
+    if (rcvd_type != expected_type) {
+        ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
+        return 0;
+    }
+
     cert = get1_cert_status(ctx, (*resp)->body->type, crep);
     if (cert == NULL) {
         ERR_add_error_data(1, "; cannot extract certificate from response");
@@ -618,7 +738,8 @@ static int cert_response(OSSL_CMP_CTX *ctx, int sleep, int rid,
      * if the CMP server returned certificates in the caPubs field, copy them
      * to the context so that they can be retrieved if necessary
      */
-    if (crepmsg->caPubs != NULL
+    if (crepmsg != NULL
+            && crepmsg->caPubs != NULL
             && !ossl_cmp_ctx_set1_caPubs(ctx, crepmsg->caPubs))
         return 0;
 
@@ -709,6 +830,9 @@ int OSSL_CMP_try_certreq(OSSL_CMP_CTX *ctx, int req_type,
     if (ctx->status != OSSL_CMP_PKISTATUS_waiting) { /* not polling already */
         if (!initial_certreq(ctx, req_type, crm, &rep, rep_type))
             goto err;
+
+        if (!save_senderNonce_if_waiting(ctx, rep, rid))
+            return 0;
     } else {
         if (req_type < 0)
             return ossl_cmp_exchange_error(ctx, OSSL_CMP_PKISTATUS_rejection,
@@ -750,6 +874,9 @@ X509 *OSSL_CMP_exec_certreq(OSSL_CMP_CTX *ctx, int req_type,
     if (!initial_certreq(ctx, req_type, crm, &rep, rep_type))
         goto err;
 
+    if (!save_senderNonce_if_waiting(ctx, rep, rid))
+        return 0;
+
     if (cert_response(ctx, 1 /* sleep */, rid, &rep, NULL, req_type, rep_type)
         <= 0)
         goto err;
@@ -787,7 +914,7 @@ int OSSL_CMP_exec_RR_ses(OSSL_CMP_CTX *ctx)
         goto end;
 
     ctx->status = OSSL_CMP_PKISTATUS_trans;
-    if (!send_receive_check(ctx, rr, &rp, OSSL_CMP_PKIBODY_RP))
+    if (!send_receive_also_delayed(ctx, rr, &rp, OSSL_CMP_PKIBODY_RP))
         goto end;
 
     rrep = rp->body->value.rp;
@@ -908,7 +1035,7 @@ STACK_OF(OSSL_CMP_ITAV) *OSSL_CMP_exec_GENM_ses(OSSL_CMP_CTX *ctx)
         goto err;
 
     ctx->status = OSSL_CMP_PKISTATUS_trans;
-    if (!send_receive_check(ctx, genm, &genp, OSSL_CMP_PKIBODY_GENP))
+    if (!send_receive_also_delayed(ctx, genm, &genp, OSSL_CMP_PKIBODY_GENP))
         goto err;
     ctx->status = OSSL_CMP_PKISTATUS_accepted;
 
diff --git a/crypto/cmp/cmp_ctx.c b/crypto/cmp/cmp_ctx.c
index 5e542200e9..cc62ae4e4e 100644
--- a/crypto/cmp/cmp_ctx.c
+++ b/crypto/cmp/cmp_ctx.c
@@ -183,6 +183,7 @@ int OSSL_CMP_CTX_reinit(OSSL_CMP_CTX *ctx)
         && ossl_cmp_ctx_set1_caPubs(ctx, NULL)
         && ossl_cmp_ctx_set1_extraCertsIn(ctx, NULL)
         && ossl_cmp_ctx_set1_validatedSrvCert(ctx, NULL)
+        && ossl_cmp_ctx_set1_first_senderNonce(ctx, NULL)
         && OSSL_CMP_CTX_set1_transactionID(ctx, NULL)
         && OSSL_CMP_CTX_set1_senderNonce(ctx, NULL)
         && ossl_cmp_ctx_set1_recipNonce(ctx, NULL);
@@ -226,6 +227,7 @@ void OSSL_CMP_CTX_free(OSSL_CMP_CTX *ctx)
     ASN1_OCTET_STRING_free(ctx->transactionID);
     ASN1_OCTET_STRING_free(ctx->senderNonce);
     ASN1_OCTET_STRING_free(ctx->recipNonce);
+    ASN1_OCTET_STRING_free(ctx->first_senderNonce);
     OSSL_CMP_ITAVs_free(ctx->geninfo_ITAVs);
     OSSL_STACK_OF_X509_free(ctx->extraCertsOut);
 
@@ -814,6 +816,9 @@ DEFINE_set1_ASN1_OCTET_STRING(ossl_cmp_ctx, recipNonce)
 /* Stores the given nonce as the last senderNonce sent out */
 DEFINE_set1_ASN1_OCTET_STRING(OSSL_CMP_CTX, senderNonce)
 
+/* store the first req sender nonce for verifying delayed delivery */
+DEFINE_set1_ASN1_OCTET_STRING(ossl_cmp_ctx, first_senderNonce)
+
 /* Set the proxy server to use for HTTP(S) connections */
 DEFINE_OSSL_CMP_CTX_set1(proxy, char)
 
diff --git a/crypto/cmp/cmp_local.h b/crypto/cmp/cmp_local.h
index b8da48ac43..175cc2575c 100644
--- a/crypto/cmp/cmp_local.h
+++ b/crypto/cmp/cmp_local.h
@@ -95,6 +95,7 @@ struct ossl_cmp_ctx_st {
     ASN1_OCTET_STRING *transactionID; /* the current transaction ID */
     ASN1_OCTET_STRING *senderNonce; /* last nonce sent */
     ASN1_OCTET_STRING *recipNonce; /* last nonce received */
+    ASN1_OCTET_STRING *first_senderNonce; /* sender nonce when starting to poll */
     ASN1_UTF8STRING *freeText; /* optional string to include each msg */
     STACK_OF(OSSL_CMP_ITAV) *geninfo_ITAVs;
     int implicitConfirm; /* set implicitConfirm in IR/KUR/CR messages */
@@ -823,6 +824,8 @@ int ossl_cmp_ctx_set1_extraCertsIn(OSSL_CMP_CTX *ctx,
 int ossl_cmp_ctx_set1_recipNonce(OSSL_CMP_CTX *ctx,
                                  const ASN1_OCTET_STRING *nonce);
 EVP_PKEY *ossl_cmp_ctx_get0_newPubkey(const OSSL_CMP_CTX *ctx);
+int ossl_cmp_ctx_set1_first_senderNonce(OSSL_CMP_CTX *ctx,
+                                        const ASN1_OCTET_STRING *nonce);
 
 /* from cmp_status.c */
 int ossl_cmp_pkisi_get_status(const OSSL_CMP_PKISI *si);
@@ -939,6 +942,7 @@ ossl_cmp_certrepmessage_get0_certresponse(const OSSL_CMP_CERTREPMESSAGE *crm,
 X509 *ossl_cmp_certresponse_get1_cert(const OSSL_CMP_CTX *ctx,
                                       const OSSL_CMP_CERTRESPONSE *crep);
 OSSL_CMP_MSG *ossl_cmp_msg_load(const char *file);
+int ossl_cmp_is_error_with_waiting(const OSSL_CMP_MSG *msg);
 
 /* from cmp_protect.c */
 int ossl_cmp_msg_add_extraCerts(OSSL_CMP_CTX *ctx, OSSL_CMP_MSG *msg);
@@ -958,6 +962,8 @@ int ossl_cmp_verify_popo(const OSSL_CMP_CTX *ctx,
                          const OSSL_CMP_MSG *msg, int accept_RAVerified);
 
 /* from cmp_client.c */
+/* expected max time per msg round trip, used for last try during polling: */
+# define OSSL_CMP_EXPECTED_RESP_TIME 2
 int ossl_cmp_exchange_certConf(OSSL_CMP_CTX *ctx, int certReqId,
                                int fail_info, const char *txt);
 int ossl_cmp_exchange_error(OSSL_CMP_CTX *ctx, int status, int fail_info,
diff --git a/crypto/cmp/cmp_msg.c b/crypto/cmp/cmp_msg.c
index e00afc809e..1b9e275d7a 100644
--- a/crypto/cmp/cmp_msg.c
+++ b/crypto/cmp/cmp_msg.c
@@ -1200,3 +1200,13 @@ int i2d_OSSL_CMP_MSG_bio(BIO *bio, const OSSL_CMP_MSG *msg)
 {
     return ASN1_i2d_bio_of(OSSL_CMP_MSG, i2d_OSSL_CMP_MSG, bio, msg);
 }
+
+int ossl_cmp_is_error_with_waiting(const OSSL_CMP_MSG *msg)
+{
+    if (!ossl_assert(msg != NULL))
+        return 0;
+
+    return (OSSL_CMP_MSG_get_bodytype(msg) == OSSL_CMP_PKIBODY_ERROR
+            && ossl_cmp_pkisi_get_status(msg->body->value.error->pKIStatusInfo)
+            == OSSL_CMP_PKISTATUS_waiting);
+}
diff --git a/crypto/cmp/cmp_server.c b/crypto/cmp/cmp_server.c
index 06ef8fbb61..1e3ca15e89 100644
--- a/crypto/cmp/cmp_server.c
+++ b/crypto/cmp/cmp_server.c
@@ -32,6 +32,8 @@ struct ossl_cmp_srv_ctx_st
     OSSL_CMP_SRV_error_cb_t process_error;
     OSSL_CMP_SRV_certConf_cb_t process_certConf;
     OSSL_CMP_SRV_pollReq_cb_t process_pollReq;
+    OSSL_CMP_SRV_reset_transaction_cb_t reset_transaction;
+    OSSL_CMP_SRV_delayed_delivery_cb_t delayed_delivery;
 
     int sendUnprotectedErrors; /* Send error and rejection msgs unprotected */
     int acceptUnprotected;     /* Accept requests with no/invalid prot. */
@@ -89,6 +91,19 @@ int OSSL_CMP_SRV_CTX_init(OSSL_CMP_SRV_CTX *srv_ctx, void *custom_ctx,
     return 1;
 }
 
+int OSSL_CMP_SRV_CTX_setup_polling(OSSL_CMP_SRV_CTX *srv_ctx,
+                                   OSSL_CMP_SRV_reset_transaction_cb_t reset_transaction,
+                                   OSSL_CMP_SRV_delayed_delivery_cb_t delayed_delivery)
+{
+    if (srv_ctx == NULL) {
+        ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    srv_ctx->reset_transaction = reset_transaction;
+    srv_ctx->delayed_delivery = delayed_delivery;
+    return 1;
+}
+
 OSSL_CMP_CTX *OSSL_CMP_SRV_CTX_get0_cmp_ctx(const OSSL_CMP_SRV_CTX *srv_ctx)
 {
     if (srv_ctx == NULL) {
@@ -149,6 +164,32 @@ int OSSL_CMP_SRV_CTX_set_grant_implicit_confirm(OSSL_CMP_SRV_CTX *srv_ctx,
     return 1;
 }
 
+/* Return error msg with waiting status if polling is initiated, else NULL. */
+static OSSL_CMP_MSG *delayed_delivery(OSSL_CMP_SRV_CTX *srv_ctx,
+                                      const OSSL_CMP_MSG *req)
+{
+    OSSL_CMP_MSG *msg = NULL;
+    OSSL_CMP_PKISI *si = NULL;
+    int ret;
+
+    if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL
+                     && srv_ctx->delayed_delivery != NULL))
+        return NULL;
+
+    ret = srv_ctx->delayed_delivery(srv_ctx, req);
+    if (ret == 0 || !ossl_assert(ret != -1))
+        return NULL;
+
+    if ((si = OSSL_CMP_STATUSINFO_new(OSSL_CMP_PKISTATUS_waiting, 0, NULL))
+        == NULL)
+        return NULL;
+
+    msg = ossl_cmp_error_new(srv_ctx->ctx, si, 0,
+                             NULL, srv_ctx->sendUnprotectedErrors);
+    OSSL_CMP_PKISI_free(si);
+    return msg;
+}
+
 /*
  * Processes an ir/cr/p10cr/kur and returns a certification response.
  * Only handles the first certification request contained in req
@@ -387,13 +428,66 @@ static OSSL_CMP_MSG *process_certConf(OSSL_CMP_SRV_CTX *srv_ctx,
     return msg;
 }
 
+/* pollreq should be handled separately, to avoid recursive call */
+static OSSL_CMP_MSG *process_non_polling_request(OSSL_CMP_SRV_CTX *srv_ctx,
+                                                 const OSSL_CMP_MSG *req)
+{
+    OSSL_CMP_MSG *rsp = NULL;
+
+    if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL
+                     && req->body != NULL))
+        return NULL;
+
+    switch (OSSL_CMP_MSG_get_bodytype(req)) {
+    case OSSL_CMP_PKIBODY_IR:
+    case OSSL_CMP_PKIBODY_CR:
+    case OSSL_CMP_PKIBODY_P10CR:
+    case OSSL_CMP_PKIBODY_KUR:
+        if (srv_ctx->process_cert_request == NULL)
+            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
+        else
+            rsp = process_cert_request(srv_ctx, req);
+        break;
+    case OSSL_CMP_PKIBODY_RR:
+        if (srv_ctx->process_rr == NULL)
+            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
+        else
+            rsp = process_rr(srv_ctx, req);
+        break;
+    case OSSL_CMP_PKIBODY_GENM:
+        if (srv_ctx->process_genm == NULL)
+            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
+        else
+            rsp = process_genm(srv_ctx, req);
+        break;
+    case OSSL_CMP_PKIBODY_ERROR:
+        if (srv_ctx->process_error == NULL)
+            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
+        else
+            rsp = process_error(srv_ctx, req);
+        break;
+    case OSSL_CMP_PKIBODY_CERTCONF:
+        if (srv_ctx->process_certConf == NULL)
+            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
+        else
+            rsp = process_certConf(srv_ctx, req);
+        break;
+    default:
+        /* Other request message types are not supported */
+        ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
+        break;
+    }
+
+    return rsp;
+}
+
 static OSSL_CMP_MSG *process_pollReq(OSSL_CMP_SRV_CTX *srv_ctx,
                                      const OSSL_CMP_MSG *req)
 {
     OSSL_CMP_POLLREQCONTENT *prc;
     OSSL_CMP_POLLREQ *pr;
     int certReqId;
-    OSSL_CMP_MSG *certReq;
+    OSSL_CMP_MSG *orig_req;
     int64_t check_after = 0;
     OSSL_CMP_MSG *msg = NULL;
 
@@ -413,12 +507,12 @@ static OSSL_CMP_MSG *process_pollReq(OSSL_CMP_SRV_CTX *srv_ctx,
         return NULL;
     }
     if (!srv_ctx->process_pollReq(srv_ctx, req, certReqId,
-                                  &certReq, &check_after))
+                                  &orig_req, &check_after))
         return NULL;
 
-    if (certReq != NULL) {
-        msg = process_cert_request(srv_ctx, certReq);
-        OSSL_CMP_MSG_free(certReq);
+    if (orig_req != NULL) {
+        msg = process_non_polling_request(srv_ctx, orig_req);
+        OSSL_CMP_MSG_free(orig_req);
     } else {
         if ((msg = ossl_cmp_pollRep_new(srv_ctx->ctx, certReqId,
                                         check_after)) == NULL)
@@ -509,6 +603,10 @@ OSSL_CMP_MSG *OSSL_CMP_SRV_process_request(OSSL_CMP_SRV_CTX *srv_ctx,
         if (!OSSL_CMP_CTX_set1_transactionID(ctx, NULL)
                 || !OSSL_CMP_CTX_set1_senderNonce(ctx, NULL))
             goto err;
+
+        if (srv_ctx->reset_transaction != NULL)
+            (void)srv_ctx->reset_transaction(srv_ctx);
+
         break;
     default:
         /* transactionID should be already initialized */
@@ -528,50 +626,17 @@ OSSL_CMP_MSG *OSSL_CMP_SRV_process_request(OSSL_CMP_SRV_CTX *srv_ctx,
     if (!req_verified)
         goto err;
 
-    switch (req_type) {
-    case OSSL_CMP_PKIBODY_IR:
-    case OSSL_CMP_PKIBODY_CR:
-    case OSSL_CMP_PKIBODY_P10CR:
-    case OSSL_CMP_PKIBODY_KUR:
-        if (srv_ctx->process_cert_request == NULL)
-            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
-        else
-            rsp = process_cert_request(srv_ctx, req);
-        break;
-    case OSSL_CMP_PKIBODY_RR:
-        if (srv_ctx->process_rr == NULL)
-            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
-        else
-            rsp = process_rr(srv_ctx, req);
-        break;
-    case OSSL_CMP_PKIBODY_GENM:
-        if (srv_ctx->process_genm == NULL)
-            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
-        else
-            rsp = process_genm(srv_ctx, req);
-        break;
-    case OSSL_CMP_PKIBODY_ERROR:
-        if (srv_ctx->process_error == NULL)
-            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
-        else
-            rsp = process_error(srv_ctx, req);
-        break;
-    case OSSL_CMP_PKIBODY_CERTCONF:
-        if (srv_ctx->process_certConf == NULL)
-            ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
-        else
-            rsp = process_certConf(srv_ctx, req);
-        break;
-    case OSSL_CMP_PKIBODY_POLLREQ:
+    if (req_type == OSSL_CMP_PKIBODY_POLLREQ) {
         if (srv_ctx->process_pollReq == NULL)
             ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
         else
             rsp = process_pollReq(srv_ctx, req);
-        break;
-    default:
-        /* Other request message types are not supported */
-        ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
-        break;
+    } else {
+        if (srv_ctx->delayed_delivery != NULL
+            && (rsp = delayed_delivery(srv_ctx, req)) != NULL) {
+            goto err;
+        }
+        rsp = process_non_polling_request(srv_ctx, req);
     }
 
  err:
@@ -627,15 +692,22 @@ OSSL_CMP_MSG *OSSL_CMP_SRV_process_request(OSSL_CMP_SRV_CTX *srv_ctx,
             break;
         /* fall through */
 
+    case OSSL_CMP_PKIBODY_ERROR:
+        if (rsp != NULL
+            && ossl_cmp_is_error_with_waiting(rsp))
+            break;
+        /* fall through */
+
     case OSSL_CMP_PKIBODY_RP:
     case OSSL_CMP_PKIBODY_PKICONF:
     case OSSL_CMP_PKIBODY_GENP:
-    case OSSL_CMP_PKIBODY_ERROR:
         /* Other terminating response message types are not supported */
         /* Prepare for next transaction, ignoring any errors here: */
         (void)OSSL_CMP_CTX_set1_transactionID(ctx, NULL);
         (void)OSSL_CMP_CTX_set1_senderNonce(ctx, NULL);
         ctx->status = OSSL_CMP_PKISTATUS_unspecified; /* transaction closed */
+        if (srv_ctx->reset_transaction != NULL)
+            (void)srv_ctx->reset_transaction(srv_ctx);
 
     default: /* not closing transaction in other cases */
         break;
diff --git a/crypto/cmp/cmp_vfy.c b/crypto/cmp/cmp_vfy.c
index 1869fae696..8d4de1017d 100644
--- a/crypto/cmp/cmp_vfy.c
+++ b/crypto/cmp/cmp_vfy.c
@@ -786,10 +786,27 @@ int ossl_cmp_msg_check_update(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
                                       CMP_R_TRANSACTIONID_UNMATCHED))
         return 0;
 
+    /*
+     * enable clearing irrelevant errors in attempts to validate recipient nonce
+     * in case of delayed delivery.
+     */
+    (void)ERR_set_mark();
     /* compare received nonce with the one we sent */
     if (!check_transactionID_or_nonce(ctx->senderNonce, hdr->recipNonce,
-                                      CMP_R_RECIPNONCE_UNMATCHED))
-        return 0;
+                                      CMP_R_RECIPNONCE_UNMATCHED)) {
+        /* check if we are polling and received final response */
+        if (ctx->first_senderNonce == NULL
+            || OSSL_CMP_MSG_get_bodytype(msg) == OSSL_CMP_PKIBODY_POLLREP
+            /* compare received nonce with our sender nonce at poll start */
+            || !check_transactionID_or_nonce(ctx->first_senderNonce,
+                                             hdr->recipNonce,
+                                             CMP_R_RECIPNONCE_UNMATCHED)) {
+            (void)ERR_clear_last_mark();
+            return 0;
+        }
+    }
+    /* discard any intermediate error while trying to check recipient nonce */
+    (void)ERR_pop_to_mark();
 
     /* if not yet present, learn transactionID */
     if (ctx->transactionID == NULL