Add OSSL_CMP_CTX_get0_validatedSrvCert(), correcting OSSL_CMP_validate_msg()

Also change ossl_cmp_ctx_set0_validatedSrvCert() to ossl_cmp_ctx_set1_validatedSrvCert(),
and add respective tests as well as the -srvcertout CLI option using the new function.

Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.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/18656)

3 files changed, 19 insertions, 27 deletions

diff --git a/crypto/cmp/cmp_ctx.c b/crypto/cmp/cmp_ctx.c
index 207f65430c..0fcb3c7ae5 100644
--- a/crypto/cmp/cmp_ctx.c
+++ b/crypto/cmp/cmp_ctx.c
@@ -166,7 +166,7 @@ int OSSL_CMP_CTX_reinit(OSSL_CMP_CTX *ctx)
         && ossl_cmp_ctx_set1_newChain(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_validatedSrvCert(ctx, NULL)
         && OSSL_CMP_CTX_set1_transactionID(ctx, NULL)
         && OSSL_CMP_CTX_set1_senderNonce(ctx, NULL)
         && ossl_cmp_ctx_set1_recipNonce(ctx, NULL);
@@ -275,15 +275,6 @@ DEFINE_OSSL_CMP_CTX_get0(statusString, OSSL_CMP_PKIFREETEXT)
 
 DEFINE_OSSL_set0(ossl_cmp_ctx, statusString, OSSL_CMP_PKIFREETEXT)
 
-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 be rejected */
 DEFINE_OSSL_set(OSSL_CMP_CTX, certConf_cb, OSSL_CMP_certConf_cb_t)
 
@@ -585,6 +576,8 @@ int PREFIX##_set1_##FIELD(OSSL_CMP_CTX *ctx, TYPE *val) \
     return 1; \
 }
 
+DEFINE_OSSL_set1_up_ref(ossl_cmp_ctx, validatedSrvCert, X509)
+
 /*
  * Pins the server certificate to be directly trusted (even if it is expired)
  * for verifying response messages.
@@ -718,6 +711,9 @@ DEFINE_OSSL_CMP_CTX_set1(p10CSR, X509_REQ)
  */
 DEFINE_OSSL_set0(ossl_cmp_ctx, newCert, X509)
 
+/* Get successfully validated server cert, if any, of current transaction */
+DEFINE_OSSL_CMP_CTX_get0(validatedSrvCert, X509)
+
 /*
  * Get the (newly received in IP/KUP/CP) client certificate from the context
  * This only permits for one client cert to be received...
diff --git a/crypto/cmp/cmp_local.h b/crypto/cmp/cmp_local.h
index 255eb58ba6..3718970ff8 100644
--- a/crypto/cmp/cmp_local.h
+++ b/crypto/cmp/cmp_local.h
@@ -779,7 +779,7 @@ int ossl_cmp_print_log(OSSL_CMP_severity level, const OSSL_CMP_CTX *ctx,
 # define ossl_cmp_info(ctx, msg)  ossl_cmp_log(INFO,  ctx, msg)
 # define ossl_cmp_debug(ctx, msg) ossl_cmp_log(DEBUG, ctx, msg)
 # define ossl_cmp_trace(ctx, msg) ossl_cmp_log(TRACE, ctx, msg)
-int ossl_cmp_ctx_set0_validatedSrvCert(OSSL_CMP_CTX *ctx, X509 *cert);
+int ossl_cmp_ctx_set1_validatedSrvCert(OSSL_CMP_CTX *ctx, X509 *cert);
 int ossl_cmp_ctx_set_status(OSSL_CMP_CTX *ctx, int status);
 int ossl_cmp_ctx_set0_statusString(OSSL_CMP_CTX *ctx,
                                    OSSL_CMP_PKIFREETEXT *text);
diff --git a/crypto/cmp/cmp_vfy.c b/crypto/cmp/cmp_vfy.c
index a269ef49da..543a978c0f 100644
--- a/crypto/cmp/cmp_vfy.c
+++ b/crypto/cmp/cmp_vfy.c
@@ -354,7 +354,7 @@ static int check_msg_given_cert(const OSSL_CMP_CTX *ctx, X509 *cert,
 /*-
  * Try all certs in given list for verifying msg, normally or in 3GPP mode.
  * If already_checked1 == NULL then certs are assumed to be the msg->extraCerts.
- * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
+ * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
  */
 static int check_msg_with_certs(OSSL_CMP_CTX *ctx, const STACK_OF(X509) *certs,
                                 const char *desc,
@@ -383,13 +383,7 @@ static int check_msg_with_certs(OSSL_CMP_CTX *ctx, const STACK_OF(X509) *certs,
         if (mode_3gpp ? check_cert_path_3gpp(ctx, msg, cert)
                       : check_cert_path(ctx, ctx->trusted, cert)) {
             /* store successful sender cert for further msgs in transaction */
-            if (!X509_up_ref(cert))
-                return 0;
-            if (!ossl_cmp_ctx_set0_validatedSrvCert(ctx, cert)) {
-                X509_free(cert);
-                return 0;
-            }
-            return 1;
+            return ossl_cmp_ctx_set1_validatedSrvCert(ctx, cert);
         }
     }
     if (in_extraCerts && n_acceptable_certs == 0)
@@ -400,7 +394,7 @@ static int check_msg_with_certs(OSSL_CMP_CTX *ctx, const STACK_OF(X509) *certs,
 /*-
  * Verify msg trying first ctx->untrusted, which should include extraCerts
  * at its front, then trying the trusted certs in truststore (if any) of ctx.
- * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
+ * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
  */
 static int check_msg_all_certs(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
                                int mode_3gpp)
@@ -445,7 +439,7 @@ static int no_log_cb(const char *func, const char *file, int line,
 
 /*-
  * Verify message signature with any acceptable and valid candidate cert.
- * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
+ * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
  */
 static int check_msg_find_cert(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
 {
@@ -482,7 +476,7 @@ static int check_msg_find_cert(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
             return 1;
         }
         /* cached sender cert has shown to be no more successfully usable */
-        (void)ossl_cmp_ctx_set0_validatedSrvCert(ctx, NULL);
+        (void)ossl_cmp_ctx_set1_validatedSrvCert(ctx, NULL);
         /* re-do the above check (just) for adding diagnostic information */
         ossl_cmp_info(ctx,
                       "trying to verify msg signature with previously validated cert");
@@ -537,7 +531,7 @@ static int check_msg_find_cert(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
  * the sender certificate can have been pinned by providing it in ctx->srvCert,
  * else it is searched in msg->extraCerts, ctx->untrusted, in ctx->trusted
  * (in this order) and is path is validated against ctx->trusted.
- * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
+ * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
  *
  * If ctx->permitTAInExtraCertsForIR is true and when validating a CMP IP msg,
  * the trust anchor for validating the IP msg may be taken from msg->extraCerts
@@ -622,15 +616,17 @@ int OSSL_CMP_validate_msg(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
                 ossl_cmp_warn(ctx, "no trust store nor pinned server cert available for verifying signature-based CMP message protection");
                 return 1;
             }
-            if (check_msg_find_cert(ctx, msg))
+            if (check_msg_find_cert(ctx, msg)) {
+                ossl_cmp_debug(ctx,
+                               "sucessfully validated signature-based CMP message protection using trust store");
                 return 1;
+            }
         } else { /* use pinned sender cert */
             /* use ctx->srvCert for signature check even if not acceptable */
             if (verify_signature(ctx, msg, scrt)) {
                 ossl_cmp_debug(ctx,
-                               "successfully validated signature-based CMP message protection");
-
-                return 1;
+                               "successfully validated signature-based CMP message protection using pinned server cert");
+                return ossl_cmp_ctx_set1_validatedSrvCert(ctx, scrt);
             }
             ossl_cmp_warn(ctx, "CMP message signature verification failed");
             ERR_raise(ERR_LIB_CMP, CMP_R_SRVCERT_DOES_NOT_VALIDATE_MSG);