Certificate Management Protocol (CMP, RFC 4210) extension to OpenSSL

    Also includes CRMF (RFC 4211) and HTTP transfer (RFC 6712)

    CMP and CRMF API is added to libcrypto, and the "cmp" app to the openssl CLI.
        Adds extensive man pages and tests.  Integration into build scripts.

    Incremental pull request based on OpenSSL commit 8869ad4a39f of 2019-04-02

    4th chunk: CMP context/parameters and utilities
    in crypto/cmp/cmp_ctx.c, crypto/cmp/cmp_util.c, and related files

Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9107)

11 files changed, 1808 insertions, 122 deletions

diff --git a/crypto/cmp/build.info b/crypto/cmp/build.info
index 6b6ccaaf49..d5ce60e040 100644
--- a/crypto/cmp/build.info
+++ b/crypto/cmp/build.info
@@ -1,2 +1,2 @@
 LIBS=../../libcrypto
-SOURCE[../../libcrypto]= cmp_asn.c cmp_err.c
+SOURCE[../../libcrypto]= cmp_asn.c cmp_ctx.c cmp_err.c cmp_util.c
diff --git a/crypto/cmp/cmp_asn.c b/crypto/cmp/cmp_asn.c
index 8555586dfd..e764e532d5 100644
--- a/crypto/cmp/cmp_asn.c
+++ b/crypto/cmp/cmp_asn.c
@@ -7,8 +7,6 @@
  * this file except in compliance with the License.  You can obtain a copy
  * in the file LICENSE in the source distribution or at
  * https://www.openssl.org/source/license.html
- *
- * CMP implementation by Martin Peylo, Miikka Viljanen, and David von Oheimb.
  */
 
 #include <openssl/asn1t.h>
@@ -166,8 +164,10 @@ int OSSL_CMP_ITAV_push0_stack_item(STACK_OF(OSSL_CMP_ITAV) **itav_sk_p,
 {
     int created = 0;
 
-    if (itav_sk_p == NULL)
+    if (itav_sk_p == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
         goto err;
+    }
 
     if (*itav_sk_p == NULL) {
         if ((*itav_sk_p = sk_OSSL_CMP_ITAV_new_null()) == NULL)
@@ -187,6 +187,26 @@ int OSSL_CMP_ITAV_push0_stack_item(STACK_OF(OSSL_CMP_ITAV) **itav_sk_p,
     return 0;
 }
 
+/* get ASN.1 encoded integer, return -1 on error */
+int ossl_cmp_asn1_get_int(const ASN1_INTEGER *a)
+{
+    int64_t res;
+
+    if (!ASN1_INTEGER_get_int64(&res, a)) {
+        CMPerr(0, ASN1_R_INVALID_NUMBER);
+        return -1;
+    }
+    if (res < INT_MIN) {
+        CMPerr(0, ASN1_R_TOO_SMALL);
+        return -1;
+    }
+    if (res > INT_MAX) {
+        CMPerr(0, ASN1_R_TOO_LARGE);
+        return -1;
+    }
+    return (int)res;
+}
+
 ASN1_CHOICE(OSSL_CMP_CERTORENCCERT) = {
     /* OSSL_CMP_CMPCERTIFICATE is effectively X509 so it is used directly */
     ASN1_EXP(OSSL_CMP_CERTORENCCERT, value.certificate, X509, 0),
diff --git a/crypto/cmp/cmp_ctx.c b/crypto/cmp/cmp_ctx.c
new file mode 100644
index 0000000000..4bec73c3b7
--- /dev/null
+++ b/crypto/cmp/cmp_ctx.c
@@ -0,0 +1,1086 @@
+/*
+ * Copyright 2007-2019 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright Nokia 2007-2019
+ * Copyright Siemens AG 2015-2019
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/trace.h>
+#include <openssl/bio.h>
+#include <openssl/ocsp.h> /* for OCSP_REVOKED_STATUS_* */
+
+#include "cmp_int.h"
+
+/* explicit #includes not strictly needed since implied by the above: */
+#include <openssl/cmp.h>
+#include <openssl/crmf.h>
+#include <openssl/err.h>
+
+/*
+ * Get current certificate store containing trusted root CA certs
+ */
+X509_STORE *OSSL_CMP_CTX_get0_trustedStore(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return NULL;
+    }
+    return ctx->trusted;
+}
+
+/*
+ * Set certificate store containing trusted (root) CA certs and possibly CRLs
+ * and a cert verification callback function used for CMP server authentication.
+ * Any already existing store entry is freed. Given NULL, the entry is reset.
+ * returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set0_trustedStore(OSSL_CMP_CTX *ctx, X509_STORE *store)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    X509_STORE_free(ctx->trusted);
+    ctx->trusted = store;
+    return 1;
+}
+
+/*
+ * Get current list of non-trusted intermediate certs
+ */
+STACK_OF(X509) *OSSL_CMP_CTX_get0_untrusted_certs(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return NULL;
+    }
+    return ctx->untrusted_certs;
+}
+
+/*
+ * Set untrusted certificates for path construction in authentication of
+ * the CMP server and potentially others (TLS server, newly enrolled cert).
+ * returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set1_untrusted_certs(OSSL_CMP_CTX *ctx, STACK_OF(X509) *certs)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    sk_X509_pop_free(ctx->untrusted_certs, X509_free);
+    if ((ctx->untrusted_certs = sk_X509_new_null()) == NULL)
+        return 0;
+    return ossl_cmp_sk_X509_add1_certs(ctx->untrusted_certs, certs, 0, 1, 0);
+}
+
+/*
+ * Allocates and initializes OSSL_CMP_CTX context structure with default values.
+ * Returns new context on success, NULL on error
+ */
+OSSL_CMP_CTX *OSSL_CMP_CTX_new(void)
+{
+    OSSL_CMP_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
+
+    if (ctx == NULL)
+        return NULL;
+
+    ctx->log_verbosity = OSSL_CMP_LOG_INFO;
+
+    ctx->status = -1;
+    ctx->failInfoCode = -1;
+
+    ctx->serverPort = OSSL_CMP_DEFAULT_PORT;
+    ctx->proxyPort = OSSL_CMP_DEFAULT_PORT;
+    ctx->msgtimeout = 2 * 60;
+
+    if ((ctx->untrusted_certs = sk_X509_new_null()) == NULL)
+        goto err;
+
+    ctx->pbm_slen = 16;
+    ctx->pbm_owf = NID_sha256;
+    ctx->pbm_itercnt = 500;
+    ctx->pbm_mac = NID_hmac_sha1;
+
+    ctx->digest = NID_sha256;
+    ctx->popoMethod = OSSL_CRMF_POPO_SIGNATURE;
+    ctx->revocationReason = CRL_REASON_NONE;
+
+    /* all other elements are initialized to 0 or NULL, respectively */
+    return ctx;
+
+ err:
+    OSSL_CMP_CTX_free(ctx);
+    return NULL;
+}
+
+/*
+ * Prepare the OSSL_CMP_CTX for next use, partly re-initializing OSSL_CMP_CTX
+ */
+int OSSL_CMP_CTX_reinit(OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+
+    ctx->status = -1;
+    ctx->failInfoCode = -1;
+
+    return ossl_cmp_ctx_set0_statusString(ctx, NULL)
+        && ossl_cmp_ctx_set0_newCert(ctx, NULL)
+        && ossl_cmp_ctx_set1_caPubs(ctx, NULL)
+        && ossl_cmp_ctx_set1_extraCertsIn(ctx, NULL)
+        && ossl_cmp_ctx_set0_validatedSrvCert(ctx, NULL)
+        && OSSL_CMP_CTX_set1_transactionID(ctx, NULL)
+        && OSSL_CMP_CTX_set1_senderNonce(ctx, NULL)
+        && ossl_cmp_ctx_set1_recipNonce(ctx, NULL);
+}
+
+/*
+ * Frees OSSL_CMP_CTX variables allocated in OSSL_CMP_CTX_new()
+ */
+void OSSL_CMP_CTX_free(OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL)
+        return;
+
+    OPENSSL_free(ctx->serverPath);
+    OPENSSL_free(ctx->serverName);
+    OPENSSL_free(ctx->proxyName);
+
+    X509_free(ctx->srvCert);
+    X509_free(ctx->validatedSrvCert);
+    X509_NAME_free(ctx->expected_sender);
+    X509_STORE_free(ctx->trusted);
+    sk_X509_pop_free(ctx->untrusted_certs, X509_free);
+
+    X509_free(ctx->clCert);
+    EVP_PKEY_free(ctx->pkey);
+    ASN1_OCTET_STRING_free(ctx->referenceValue);
+    if (ctx->secretValue != NULL)
+        OPENSSL_cleanse(ctx->secretValue->data, ctx->secretValue->length);
+    ASN1_OCTET_STRING_free(ctx->secretValue);
+
+    X509_NAME_free(ctx->recipient);
+    ASN1_OCTET_STRING_free(ctx->transactionID);
+    ASN1_OCTET_STRING_free(ctx->senderNonce);
+    ASN1_OCTET_STRING_free(ctx->recipNonce);
+    sk_OSSL_CMP_ITAV_pop_free(ctx->geninfo_ITAVs, OSSL_CMP_ITAV_free);
+    sk_X509_pop_free(ctx->extraCertsOut, X509_free);
+
+    EVP_PKEY_free(ctx->newPkey);
+    X509_NAME_free(ctx->issuer);
+    X509_NAME_free(ctx->subjectName);
+    sk_GENERAL_NAME_pop_free(ctx->subjectAltNames, GENERAL_NAME_free);
+    sk_X509_EXTENSION_pop_free(ctx->reqExtensions, X509_EXTENSION_free);
+    sk_POLICYINFO_pop_free(ctx->policies, POLICYINFO_free);
+    X509_free(ctx->oldCert);
+    X509_REQ_free(ctx->p10CSR);
+
+    sk_OSSL_CMP_ITAV_pop_free(ctx->genm_ITAVs, OSSL_CMP_ITAV_free);
+
+    sk_ASN1_UTF8STRING_pop_free(ctx->statusString, ASN1_UTF8STRING_free);
+    X509_free(ctx->newCert);
+    sk_X509_pop_free(ctx->caPubs, X509_free);
+    sk_X509_pop_free(ctx->extraCertsIn, X509_free);
+
+    OPENSSL_free(ctx);
+}
+
+int ossl_cmp_ctx_set_status(OSSL_CMP_CTX *ctx, int status)
+{
+    if (!ossl_assert(ctx != NULL))
+         return 0;
+    ctx->status = status;
+    return 1;
+}
+
+/*
+ * Returns the PKIStatus from the last CertRepMessage
+ * or Revocation Response or error message, -1 on error
+ */
+int OSSL_CMP_CTX_get_status(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return -1;
+    }
+    return ctx->status;
+}
+
+/*
+ * Returns the statusString from the last CertRepMessage
+ * or Revocation Response or error message, NULL on error
+ */
+OSSL_CMP_PKIFREETEXT *OSSL_CMP_CTX_get0_statusString(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return NULL;
+    }
+    return ctx->statusString;
+}
+
+int ossl_cmp_ctx_set0_statusString(OSSL_CMP_CTX *ctx,
+                                   OSSL_CMP_PKIFREETEXT *text)
+{
+    if (!ossl_assert(ctx != NULL))
+        return 0;
+    sk_ASN1_UTF8STRING_pop_free(ctx->statusString, ASN1_UTF8STRING_free);
+    ctx->statusString = text;
+    return 1;
+}
+
+int ossl_cmp_ctx_set0_validatedSrvCert(OSSL_CMP_CTX *ctx, X509 *cert)
+{
+    if (!ossl_assert(ctx != NULL))
+        return 0;
+    X509_free(ctx->validatedSrvCert);
+    ctx->validatedSrvCert = cert;
+    return 1;
+}
+
+/*
+ * Set callback function for checking if the cert is ok or should
+ * it be rejected.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set_certConf_cb(OSSL_CMP_CTX *ctx, OSSL_cmp_certConf_cb_t cb)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    ctx->certConf_cb = cb;
+    return 1;
+}
+
+/*
+ * Set argument, respectively a pointer to a structure containing arguments,
+ * optionally to be used by the certConf callback.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set_certConf_cb_arg(OSSL_CMP_CTX *ctx, void *arg)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    ctx->certConf_cb_arg = arg;
+    return 1;
+}
+
+/*
+ * Get argument, respectively the pointer to a structure containing arguments,
+ * optionally to be used by certConf callback.
+ * Returns callback argument set previously (NULL if not set or on error)
+ */
+void *OSSL_CMP_CTX_get_certConf_cb_arg(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return NULL;
+    }
+    return ctx->certConf_cb_arg;
+}
+
+#ifndef OPENSSL_NO_TRACE
+static size_t ossl_cmp_log_trace_cb(const char *buf, size_t cnt,
+                                    int category, int cmd, void *vdata)
+{
+    OSSL_CMP_CTX *ctx = vdata;
+    const char *prefix_msg;
+    OSSL_CMP_severity level = -1;
+    char *func = NULL;
+    char *file = NULL;
+    int line = 0;
+
+    if (buf == NULL || cnt == 0 || cmd != OSSL_TRACE_CTRL_WRITE || ctx == NULL)
+        return 0;
+    if (ctx->log_cb == NULL)
+        return 1; /* silently drop message */
+
+    prefix_msg = ossl_cmp_log_parse_metadata(buf, &level, &func, &file, &line);
+
+    if (level > ctx->log_verbosity) /* excludes the case level is unknown */
+        goto end; /* suppress output since severity is not sufficient */
+
+    if (!ctx->log_cb(func != NULL ? func : "(no func)",
+                     file != NULL ? file : "(no file)",
+                     line, level, prefix_msg))
+        cnt = 0;
+
+ end:
+    OPENSSL_free(func);
+    OPENSSL_free(file);
+    return cnt;
+}
+#endif
+
+/*
+ * Set a callback function for error reporting and logging messages.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set_log_cb(OSSL_CMP_CTX *ctx, OSSL_cmp_log_cb_t cb)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    ctx->log_cb = cb;
+
+#ifndef OPENSSL_NO_TRACE
+    /* do also in case cb == NULL, to switch off logging output: */
+    if (!OSSL_trace_set_callback(OSSL_TRACE_CATEGORY_CMP,
+                                 ossl_cmp_log_trace_cb, ctx))
+        return 0;
+#endif
+
+    return 1;
+}
+
+/* Print OpenSSL and CMP errors via the log cb of the ctx or ERR_print_errors */
+void OSSL_CMP_CTX_print_errors(OSSL_CMP_CTX *ctx)
+{
+    OSSL_CMP_print_errors_cb(ctx == NULL ? NULL : ctx->log_cb);
+}
+
+/*
+ * Set or clear the reference value to be used for identification
+ * (i.e., the user name) when using PBMAC.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set1_referenceValue(OSSL_CMP_CTX *ctx,
+                                     const unsigned char *ref, int len)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    return ossl_cmp_asn1_octet_string_set1_bytes(&ctx->referenceValue, ref,
+                                                 len);
+}
+
+/*
+ * Set or clear the password to be used for protecting messages with PBMAC.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set1_secretValue(OSSL_CMP_CTX *ctx, const unsigned char *sec,
+                                  const int len)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    if (ctx->secretValue != NULL)
+        OPENSSL_cleanse(ctx->secretValue->data, ctx->secretValue->length);
+    return ossl_cmp_asn1_octet_string_set1_bytes(&ctx->secretValue, sec, len);
+}
+
+/*
+ * Returns the stack of certificates received in a response message.
+ * The stack is duplicated so the caller must handle freeing it!
+ * Returns pointer to created stack on success, NULL on error
+ */
+STACK_OF(X509) *OSSL_CMP_CTX_get1_extraCertsIn(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return NULL;
+    }
+    if (ctx->extraCertsIn == NULL)
+        return sk_X509_new_null();
+    return X509_chain_up_ref(ctx->extraCertsIn);
+}
+
+/*
+ * Copies any given stack of inbound X509 certificates to extraCertsIn
+ * of the OSSL_CMP_CTX structure so that they may be retrieved later.
+ * Returns 1 on success, 0 on error.
+ */
+int ossl_cmp_ctx_set1_extraCertsIn(OSSL_CMP_CTX *ctx,
+                                   STACK_OF(X509) *extraCertsIn)
+{
+    if (!ossl_assert(ctx != NULL))
+        return 0;
+
+    sk_X509_pop_free(ctx->extraCertsIn, X509_free);
+    ctx->extraCertsIn = NULL;
+    if (extraCertsIn == NULL)
+        return 1;
+    return (ctx->extraCertsIn = X509_chain_up_ref(extraCertsIn)) != NULL;
+}
+
+/*
+ * Duplicate and set the given stack as the new stack of X509
+ * certificates to send out in the extraCerts field.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set1_extraCertsOut(OSSL_CMP_CTX *ctx,
+                                    STACK_OF(X509) *extraCertsOut)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+
+    sk_X509_pop_free(ctx->extraCertsOut, X509_free);
+    ctx->extraCertsOut = NULL;
+    if (extraCertsOut == NULL)
+        return 1;
+    return (ctx->extraCertsOut = X509_chain_up_ref(extraCertsOut)) != NULL;
+}
+
+/*
+ * Add the given policy info object
+ * to the X509_EXTENSIONS of the requested certificate template.
+ * Returns 1 on success, 0 on error.
+ */
+int OSSL_CMP_CTX_push0_policy(OSSL_CMP_CTX *ctx, POLICYINFO *pinfo)
+{
+    if (ctx == NULL || pinfo == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+
+    if (ctx->policies == NULL
+            && (ctx->policies = CERTIFICATEPOLICIES_new()) == NULL)
+        return 0;
+
+    return sk_POLICYINFO_push(ctx->policies, pinfo);
+}
+
+/*
+ * Add an ITAV for geninfo of the PKI message header
+ */
+int OSSL_CMP_CTX_push0_geninfo_ITAV(OSSL_CMP_CTX *ctx, OSSL_CMP_ITAV *itav)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    return OSSL_CMP_ITAV_push0_stack_item(&ctx->geninfo_ITAVs, itav);
+}
+
+/*
+ * Add an itav for the body of outgoing general messages
+ */
+int OSSL_CMP_CTX_push0_genm_ITAV(OSSL_CMP_CTX *ctx, OSSL_CMP_ITAV *itav)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    return OSSL_CMP_ITAV_push0_stack_item(&ctx->genm_ITAVs, itav);
+}
+
+/*
+ * Returns a duplicate of the stack of X509 certificates that
+ * were received in the caPubs field of the last CertRepMessage.
+ * Returns NULL on error
+ */
+STACK_OF(X509) *OSSL_CMP_CTX_get1_caPubs(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return NULL;
+    }
+    if (ctx->caPubs == NULL)
+        return sk_X509_new_null();
+    return X509_chain_up_ref(ctx->caPubs);
+}
+
+/*
+ * Duplicate and copy the given stack of certificates to the given
+ * OSSL_CMP_CTX structure so that they may be retrieved later.
+ * Returns 1 on success, 0 on error
+ */
+int ossl_cmp_ctx_set1_caPubs(OSSL_CMP_CTX *ctx, STACK_OF(X509) *caPubs)
+{
+    if (!ossl_assert(ctx != NULL))
+        return 0;
+
+    sk_X509_pop_free(ctx->caPubs, X509_free);
+    ctx->caPubs = NULL;
+    if (caPubs == NULL)
+        return 1;
+    return (ctx->caPubs = X509_chain_up_ref(caPubs)) != NULL;
+}
+
+#define char_dup OPENSSL_strdup
+#define char_free OPENSSL_free
+#define DEFINE_OSSL_CMP_CTX_set1(FIELD, TYPE) /* this uses _dup */ \
+int OSSL_CMP_CTX_set1_##FIELD(OSSL_CMP_CTX *ctx, const TYPE *val) \
+{ \
+    TYPE *val_dup = NULL; \
+    \
+    if (ctx == NULL) { \
+        CMPerr(0, CMP_R_NULL_ARGUMENT); \
+        return 0; \
+    } \
+    \
+    if (val != NULL && (val_dup = TYPE##_dup(val)) == NULL) \
+        return 0; \
+    TYPE##_free(ctx->FIELD); \
+    ctx->FIELD = val_dup; \
+    return 1; \
+}
+
+#define DEFINE_OSSL_CMP_CTX_set1_up_ref(FIELD, TYPE) \
+int OSSL_CMP_CTX_set1_##FIELD(OSSL_CMP_CTX *ctx, TYPE *val) \
+{ \
+    if (ctx == NULL) { \
+        CMPerr(0, CMP_R_NULL_ARGUMENT); \
+        return 0; \
+    } \
+    \
+    if (val != NULL && !TYPE##_up_ref(val)) \
+        return 0; \
+    TYPE##_free(ctx->FIELD); \
+    ctx->FIELD = val; \
+    return 1; \
+}
+
+/*
+ * Pins the server certificate to be directly trusted (even if it is expired)
+ * for verifying response messages.
+ * Cert pointer is not consumed. It may be NULL to clear the entry.
+ * Returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1_up_ref(srvCert, X509)
+
+/*
+ * Set the X509 name of the recipient. Set in the PKIHeader.
+ * returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1(recipient, X509_NAME)
+
+/*
+ * Store the X509 name of the expected sender in the PKIHeader of responses.
+ * Returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1(expected_sender, X509_NAME)
+
+/*
+ * Set the X509 name of the issuer. Set in the PKIHeader.
+ * Returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1(issuer, X509_NAME)
+
+/*
+ * Set the subject name that will be placed in the certificate
+ * request. This will be the subject name on the received certificate.
+ * Returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1(subjectName, X509_NAME)
+
+/*
+ * Set the X.509v3 certificate request extensions to be used in IR/CR/KUR.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set0_reqExtensions(OSSL_CMP_CTX *ctx, X509_EXTENSIONS *exts)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+
+    if (sk_GENERAL_NAME_num(ctx->subjectAltNames) > 0 && exts != NULL
+            && X509v3_get_ext_by_NID(exts, NID_subject_alt_name, -1) >= 0) {
+        CMPerr(0, CMP_R_MULTIPLE_SAN_SOURCES);
+        return 0;
+    }
+    sk_X509_EXTENSION_pop_free(ctx->reqExtensions, X509_EXTENSION_free);
+    ctx->reqExtensions = exts;
+    return 1;
+}
+
+/* returns 1 if ctx contains a Subject Alternative Name extension, else 0 */
+int OSSL_CMP_CTX_reqExtensions_have_SAN(OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return -1;
+    }
+    /* if one of the following conditions 'fail' this is not an error */
+    return ctx->reqExtensions != NULL
+        && X509v3_get_ext_by_NID(ctx->reqExtensions,
+                                 NID_subject_alt_name, -1) >= 0;
+}
+
+/*
+ * Add a GENERAL_NAME structure that will be added to the CRMF
+ * request's extensions field to request subject alternative names.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_push1_subjectAltName(OSSL_CMP_CTX *ctx,
+                                      const GENERAL_NAME *name)
+{
+    GENERAL_NAME *name_dup;
+
+    if (ctx == NULL || name == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+
+    if (OSSL_CMP_CTX_reqExtensions_have_SAN(ctx) == 1) {
+        CMPerr(0, CMP_R_MULTIPLE_SAN_SOURCES);
+        return 0;
+    }
+
+    if (ctx->subjectAltNames == NULL
+            && (ctx->subjectAltNames = sk_GENERAL_NAME_new_null()) == NULL)
+        return 0;
+    if ((name_dup = GENERAL_NAME_dup(name)) == NULL)
+        return 0;
+    if (!sk_GENERAL_NAME_push(ctx->subjectAltNames, name_dup)) {
+        GENERAL_NAME_free(name_dup);
+        return 0;
+    }
+    return 1;
+}
+
+/*
+ * Set our own client certificate, used for example in KUR and when
+ * doing the IR with existing certificate.
+ * Returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1_up_ref(clCert, X509)
+
+/*
+ * Set the old certificate that we are updating in KUR
+ * or the certificate to be revoked in RR, respectively.
+ * Also used as reference cert (defaulting to clCert) for deriving subject DN
+ * and SANs. Its issuer is used as default recipient in the CMP message header.
+ * Returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1_up_ref(oldCert, X509)
+
+/*
+ * Set the PKCS#10 CSR to be sent in P10CR.
+ * Returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1(p10CSR, X509_REQ)
+
+/*
+ * Sets the (newly received in IP/KUP/CP) certificate in the context.
+ * Returns 1 on success, 0 on error
+ * TODO: this only permits for one cert to be enrolled at a time.
+ */
+int ossl_cmp_ctx_set0_newCert(OSSL_CMP_CTX *ctx, X509 *cert)
+{
+    if (!ossl_assert(ctx != NULL))
+        return 0;
+
+    X509_free(ctx->newCert);
+    ctx->newCert = cert;
+    return 1;
+}
+
+/*
+ * Get the (newly received in IP/KUP/CP) client certificate from the context
+ * TODO: this only permits for one client cert to be received...
+ */
+X509 *OSSL_CMP_CTX_get0_newCert(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return NULL;
+    }
+    return ctx->newCert;
+}
+
+/*
+ * Set the client's current private key.
+ * Returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1_up_ref(pkey, EVP_PKEY)
+
+/*
+ * Set new key pair. Used e.g. when doing Key Update.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set0_newPkey(OSSL_CMP_CTX *ctx, int priv, EVP_PKEY *pkey)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+
+    EVP_PKEY_free(ctx->newPkey);
+    ctx->newPkey = pkey;
+    ctx->newPkey_priv = priv;
+    return 1;
+}
+
+/*
+ * gets the private/public key to use for certificate enrollment, NULL on error
+ */
+EVP_PKEY *OSSL_CMP_CTX_get0_newPkey(const OSSL_CMP_CTX *ctx, int priv)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return NULL;
+    }
+
+    if (ctx->newPkey != NULL)
+        return priv && !ctx->newPkey_priv ? NULL : ctx->newPkey;
+    if (ctx->p10CSR != NULL)
+        return priv ? NULL : X509_REQ_get0_pubkey(ctx->p10CSR);
+    return ctx->pkey; /* may be NULL */
+}
+
+/*
+ * Sets the given transactionID to the context.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set1_transactionID(OSSL_CMP_CTX *ctx,
+                                    const ASN1_OCTET_STRING *id)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    return ossl_cmp_asn1_octet_string_set1(&ctx->transactionID, id);
+}
+
+/*
+ * sets the given nonce to be used for the recipNonce in the next message to be
+ * created.
+ * returns 1 on success, 0 on error
+ */
+int ossl_cmp_ctx_set1_recipNonce(OSSL_CMP_CTX *ctx,
+                            const ASN1_OCTET_STRING *nonce)
+{
+    if (!ossl_assert(ctx != NULL))
+        return 0;
+    return ossl_cmp_asn1_octet_string_set1(&ctx->recipNonce, nonce);
+}
+
+/*
+ * Stores the given nonce as the last senderNonce sent out.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set1_senderNonce(OSSL_CMP_CTX *ctx,
+                                  const ASN1_OCTET_STRING *nonce)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    return ossl_cmp_asn1_octet_string_set1(&ctx->senderNonce, nonce);
+}
+
+/*
+ * Set the host name of the (HTTP) proxy server to use for all connections
+ * returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1(proxyName, char)
+
+/*
+ * Set the (HTTP) host name of the CA server.
+ * Returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1(serverName, char)
+
+/*
+ * Sets the (HTTP) proxy port to be used.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set_proxyPort(OSSL_CMP_CTX *ctx, int port)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    ctx->proxyPort = port;
+    return 1;
+}
+
+/*
+ * sets the http connect/disconnect callback function to be used for HTTP(S)
+ * returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set_http_cb(OSSL_CMP_CTX *ctx, OSSL_cmp_http_cb_t cb)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    ctx->http_cb = cb;
+    return 1;
+}
+
+/*
+ * Set argument optionally to be used by the http connect/disconnect callback.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set_http_cb_arg(OSSL_CMP_CTX *ctx, void *arg)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    ctx->http_cb_arg = arg;
+    return 1;
+}
+
+/*
+ * Get argument optionally to be used by the http connect/disconnect callback
+ * Returns callback argument set previously (NULL if not set or on error)
+ */
+void *OSSL_CMP_CTX_get_http_cb_arg(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return NULL;
+    }
+    return ctx->http_cb_arg;
+}
+
+/*
+ * Set callback function for sending CMP request and receiving response.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set_transfer_cb(OSSL_CMP_CTX *ctx, OSSL_cmp_transfer_cb_t cb)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    ctx->transfer_cb = cb;
+    return 1;
+}
+
+/*
+ * Set argument optionally to be used by the transfer callback.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set_transfer_cb_arg(OSSL_CMP_CTX *ctx, void *arg)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    ctx->transfer_cb_arg = arg;
+    return 1;
+}
+
+/*
+ * Get argument optionally to be used by the transfer callback.
+ * Returns callback argument set previously (NULL if not set or on error)
+ */
+void *OSSL_CMP_CTX_get_transfer_cb_arg(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return NULL;
+    }
+    return ctx->transfer_cb_arg;
+}
+
+/*
+ * Sets the (HTTP) server port to be used.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set_serverPort(OSSL_CMP_CTX *ctx, int port)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+    ctx->serverPort = port;
+    return 1;
+}
+
+/*
+ * Sets the HTTP path to be used on the server (e.g "pkix/").
+ * Returns 1 on success, 0 on error
+ */
+DEFINE_OSSL_CMP_CTX_set1(serverPath, char)
+
+/*
+ * Set the failInfo error code as bit encoding in OSSL_CMP_CTX.
+ * Returns 1 on success, 0 on error
+ */
+int ossl_cmp_ctx_set_failInfoCode(OSSL_CMP_CTX *ctx, int fail_info)
+{
+    if (!ossl_assert(ctx != NULL))
+        return 0;
+    ctx->failInfoCode = fail_info;
+    return 1;
+}
+
+/*
+ * Get the failInfo error code in OSSL_CMP_CTX as bit encoding.
+ * Returns bit string as integer on success, -1 on error
+ */
+int OSSL_CMP_CTX_get_failInfoCode(const OSSL_CMP_CTX *ctx)
+{
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return -1;
+    }
+    return ctx->failInfoCode;
+}
+
+/*
+ * Sets a Boolean or integer option of the context to the "val" arg.
+ * Returns 1 on success, 0 on error
+ */
+int OSSL_CMP_CTX_set_option(OSSL_CMP_CTX *ctx, int opt, int val) {
+    int min_val;
+
+    if (ctx == NULL) {
+        CMPerr(0, CMP_R_NULL_ARGUMENT);
+        return 0;
+    }
+
+    switch (opt) {
+    case OSSL_CMP_OPT_REVOCATION_REASON:
+        min_val = OCSP_REVOKED_STATUS_NOSTATUS;
+        break;
+    case OSSL_CMP_OPT_POPOMETHOD:
+        min_val = OSSL_CRMF_POPO_NONE;
+        break;
+    default:
+        min_val = 0;
+        break;
+    }
+    if (val < min_val) {
+        CMPerr(0, CMP_R_INVALID_ARGS);