Improve ossl_cmp_build_cert_chain(); publish it as X509_build_chain()

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14128)

7 files changed, 49 insertions, 74 deletions

diff --git a/crypto/cmp/cmp_client.c b/crypto/cmp/cmp_client.c
index 728ec21968..54c8f5094b 100644
--- a/crypto/cmp/cmp_client.c
+++ b/crypto/cmp/cmp_client.c
@@ -496,9 +496,8 @@ int OSSL_CMP_certConf_cb(OSSL_CMP_CTX *ctx, X509 *cert, int fail_info,
         return fail_info;
 
     ossl_cmp_debug(ctx, "trying to build chain for newly enrolled cert");
-    chain = ossl_cmp_build_cert_chain(ctx->libctx, ctx->propq,
-                                      out_trusted /* may be NULL */,
-                                      ctx->untrusted, cert);
+    chain = X509_build_chain(cert, ctx->untrusted, out_trusted /* maybe NULL */,
+                             0, ctx->libctx, ctx->propq);
     if (sk_X509_num(chain) > 0)
         X509_free(sk_X509_shift(chain)); /* remove leaf (EE) cert */
     if (out_trusted != NULL) {
diff --git a/crypto/cmp/cmp_ctx.c b/crypto/cmp/cmp_ctx.c
index 110361320d..7e7af63b4a 100644
--- a/crypto/cmp/cmp_ctx.c
+++ b/crypto/cmp/cmp_ctx.c
@@ -735,8 +735,8 @@ int OSSL_CMP_CTX_build_cert_chain(OSSL_CMP_CTX *ctx, X509_STORE *own_trusted,
         return 0;
 
     ossl_cmp_debug(ctx, "trying to build chain for own CMP signer cert");
-    chain = ossl_cmp_build_cert_chain(ctx->libctx, ctx->propq, own_trusted,
-                                      ctx->untrusted, ctx->cert);
+    chain = X509_build_chain(ctx->cert, ctx->untrusted, own_trusted, 0,
+                             ctx->libctx, ctx->propq);
     if (chain == NULL) {
         ERR_raise(ERR_LIB_CMP, CMP_R_FAILED_BUILDING_OWN_CHAIN);
         return 0;
diff --git a/crypto/cmp/cmp_local.h b/crypto/cmp/cmp_local.h
index 1ec16d4b2b..b2a3382079 100644
--- a/crypto/cmp/cmp_local.h
+++ b/crypto/cmp/cmp_local.h
@@ -749,10 +749,6 @@ int ossl_cmp_asn1_octet_string_set1(ASN1_OCTET_STRING **tgt,
                                     const ASN1_OCTET_STRING *src);
 int ossl_cmp_asn1_octet_string_set1_bytes(ASN1_OCTET_STRING **tgt,
                                           const unsigned char *bytes, int len);
-STACK_OF(X509)
-    *ossl_cmp_build_cert_chain(OSSL_LIB_CTX *libctx, const char *propq,
-                               X509_STORE *store,
-                               STACK_OF(X509) *certs, X509 *cert);
 
 /* from cmp_ctx.c */
 int ossl_cmp_print_log(OSSL_CMP_severity level, const OSSL_CMP_CTX *ctx,
diff --git a/crypto/cmp/cmp_protect.c b/crypto/cmp/cmp_protect.c
index 45bea73d13..36a6597145 100644
--- a/crypto/cmp/cmp_protect.c
+++ b/crypto/cmp/cmp_protect.c
@@ -144,9 +144,8 @@ int ossl_cmp_msg_add_extraCerts(OSSL_CMP_CTX *ctx, OSSL_CMP_MSG *msg)
         if (ctx->chain == NULL) {
             ossl_cmp_debug(ctx,
                            "trying to build chain for own CMP signer cert");
-            ctx->chain =
-                ossl_cmp_build_cert_chain(ctx->libctx, ctx->propq, NULL,
-                                          ctx->untrusted, ctx->cert);
+            ctx->chain = X509_build_chain(ctx->cert, ctx->untrusted, NULL, 0,
+                                          ctx->libctx, ctx->propq);
             if (ctx->chain != NULL) {
                 ossl_cmp_debug(ctx,
                                "success building chain for own CMP signer cert");
diff --git a/crypto/cmp/cmp_util.c b/crypto/cmp/cmp_util.c
index 56f2b0eeb8..fbb8d1e249 100644
--- a/crypto/cmp/cmp_util.c
+++ b/crypto/cmp/cmp_util.c
@@ -220,67 +220,6 @@ int ossl_cmp_X509_STORE_add1_certs(X509_STORE *store, STACK_OF(X509) *certs,
     return 1;
 }
 
-/*-
- * Builds a certificate chain starting from <cert>
- * using the optional list of intermediate CA certificates <certs>.
- * If <store> is NULL builds the chain as far down as possible, ignoring errors.
- * Else the chain must reach a trust anchor contained in <store>.
- *
- * Returns NULL on error, else a pointer to a stack of (up_ref'ed) certificates
- * starting with given EE certificate and followed by all available intermediate
- * certificates down towards any trust anchor but without including the latter.
- *
- * NOTE: If a non-NULL stack is returned the caller is responsible for freeing.
- * NOTE: In case there is more than one possibility for the chain,
- * OpenSSL seems to take the first one; check X509_verify_cert() for details.
- */
-/* TODO this should be of more general interest and thus be exported. */
-STACK_OF(X509)
-    *ossl_cmp_build_cert_chain(OSSL_LIB_CTX *libctx, const char *propq,
-                               X509_STORE *store,
-                               STACK_OF(X509) *certs, X509 *cert)
-{
-    STACK_OF(X509) *chain = NULL, *result = NULL;
-    X509_STORE *ts = store == NULL ? X509_STORE_new() : store;
-    X509_STORE_CTX *csc = NULL;
-
-    if (ts == NULL || cert == NULL) {
-        ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
-        goto err;
-    }
-
-    if ((csc = X509_STORE_CTX_new_ex(libctx, propq)) == NULL)
-        goto err;
-    if (store == NULL && certs != NULL
-            && !ossl_cmp_X509_STORE_add1_certs(ts, certs, 0))
-        goto err;
-    if (!X509_STORE_CTX_init(csc, ts, cert,
-                             store == NULL ? NULL : certs))
-        goto err;
-    /* disable any cert status/revocation checking etc. */
-    X509_VERIFY_PARAM_clear_flags(X509_STORE_CTX_get0_param(csc),
-                                  ~(X509_V_FLAG_USE_CHECK_TIME
-                                    | X509_V_FLAG_NO_CHECK_TIME));
-
-    if (X509_verify_cert(csc) <= 0 && store != NULL)
-        goto err;
-    chain = X509_STORE_CTX_get0_chain(csc);
-
-    /* result list to store the up_ref'ed not self-signed certificates */
-    if (!ossl_x509_add_certs_new(&result, chain,
-                                 X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
-                                 | X509_ADD_FLAG_NO_SS)) {
-        sk_X509_free(result);
-        result = NULL;
-    }
-
- err:
-    if (store == NULL)
-        X509_STORE_free(ts);
-    X509_STORE_CTX_free(csc);
-    return result;
-}
-
 int ossl_cmp_sk_ASN1_UTF8STRING_push_str(STACK_OF(ASN1_UTF8STRING) *sk,
                                          const char *text)
 {
diff --git a/crypto/x509/x509_vfy.c b/crypto/x509/x509_vfy.c
index 01871b9090..cb541084df 100644
--- a/crypto/x509/x509_vfy.c
+++ b/crypto/x509/x509_vfy.c
@@ -3322,6 +3322,48 @@ static int build_chain(X509_STORE_CTX *ctx)
     return -1;
 }
 
+STACK_OF(X509) *X509_build_chain(X509 *target, STACK_OF(X509) *certs,
+                                 X509_STORE *store, int with_self_signed,
+                                 OSSL_LIB_CTX *libctx, const char *propq)
+{
+    int finish_chain = store != NULL;
+    X509_STORE_CTX *ctx;
+    int flags = X509_ADD_FLAG_UP_REF;
+    STACK_OF(X509) *result = NULL;
+
+    if (target == NULL) {
+        ERR_raise(ERR_LIB_X509, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+
+    if ((ctx = X509_STORE_CTX_new_ex(libctx, propq)) == NULL)
+        return NULL;
+    if (!X509_STORE_CTX_init(ctx, store, target, finish_chain ? certs : NULL))
+        goto err;
+    if (!finish_chain)
+        X509_STORE_CTX_set0_trusted_stack(ctx, certs);
+    if (!ossl_x509_add_cert_new(&ctx->chain, target, X509_ADD_FLAG_UP_REF)) {
+        ctx->error = X509_V_ERR_OUT_OF_MEM;
+        goto err;
+    }
+    ctx->num_untrusted = 1;
+
+    if (!build_chain(ctx) && finish_chain)
+        goto err;
+
+    /* result list to store the up_ref'ed certificates */
+    if (sk_X509_num(ctx->chain) > 1 && !with_self_signed)
+        flags |= X509_ADD_FLAG_NO_SS;
+    if (!ossl_x509_add_certs_new(&result, ctx->chain, flags)) {
+        sk_X509_free(result);
+        result = NULL;
+    }
+
+ err:
+    X509_STORE_CTX_free(ctx);
+    return result;
+}
+
 static const int minbits_table[] = { 80, 112, 128, 192, 256 };
 static const int NUM_AUTH_LEVELS = OSSL_NELEM(minbits_table);
 
diff --git a/crypto/x509/x_x509.c b/crypto/x509/x_x509.c
index a4a169a97e..529d701bbb 100644
--- a/crypto/x509/x_x509.c
+++ b/crypto/x509/x_x509.c
@@ -129,7 +129,7 @@ X509 *d2i_X509(X509 **a, const unsigned char **in, long len)
 
     cert = (X509 *)ASN1_item_d2i((ASN1_VALUE **)a, in, len, (X509_it()));
     /* Only cache the extensions if the cert object was passed in */
-    if (cert != NULL && a != NULL) {
+    if (cert != NULL && a != NULL) { /* then cert == *a */
         if (!ossl_x509v3_cache_extensions(cert)) {
             if (free_on_error)
                 X509_free(cert);