Allow OBJ_create() to create an OBJ and NID with a NULL OID

We already permit this in crypto/objects/objects.txt, but not programatically,
although being able to do so programatically would be beneficial.

Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19876)

crypto/objects/obj_dat.c

@@ -729,6 +729,12 @@ int OBJ_create(const char *oid, const char *sn, const char *ln)
     ASN1_OBJECT *tmpoid = NULL;
     int ok = 0;
 
+    /* With no arguments at all, nothing can be done */
+    if (oid == NULL && sn == NULL && ln == NULL) {
+        ERR_raise(ERR_LIB_OBJ, ERR_R_PASSED_INVALID_ARGUMENT);
+        return 0;
+    }
+
     /* Check to see if short or long name already present */
     if ((sn != NULL && OBJ_sn2nid(sn) != NID_undef)
             || (ln != NULL && OBJ_ln2nid(ln) != NID_undef)) {
@@ -736,10 +742,15 @@ int OBJ_create(const char *oid, const char *sn, const char *ln)
         return 0;
     }
 
-    /* Convert numerical OID string to an ASN1_OBJECT structure */
-    tmpoid = OBJ_txt2obj(oid, 1);
-    if (tmpoid == NULL)
-        return 0;
+    if (oid != NULL) {
+        /* Convert numerical OID string to an ASN1_OBJECT structure */
+        tmpoid = OBJ_txt2obj(oid, 1);
+        if (tmpoid == NULL)
+            return 0;
+    } else {
+        /* Create a no-OID ASN1_OBJECT */
+        tmpoid = ASN1_OBJECT_new();
+    }
 
     if (!ossl_obj_write_lock(1)) {
         ERR_raise(ERR_LIB_OBJ, ERR_R_UNABLE_TO_GET_WRITE_LOCK);
@@ -748,7 +759,8 @@ int OBJ_create(const char *oid, const char *sn, const char *ln)
     }
 
     /* If NID is not NID_undef then object already exists */
-    if (ossl_obj_obj2nid(tmpoid, 0) != NID_undef) {
+    if (oid != NULL
+        && ossl_obj_obj2nid(tmpoid, 0) != NID_undef) {
         ERR_raise(ERR_LIB_OBJ, OBJ_R_OID_EXISTS);
         goto err;
     }

doc/man3/OBJ_nid2obj.pod

@@ -89,7 +89,8 @@ OBJ_dup() returns a copy of I<o>.
 OBJ_create() adds a new object to the internal table. I<oid> is the
 numerical form of the object, I<sn> the short name and I<ln> the
 long name. A new NID is returned for the created object in case of
-success and NID_undef in case of failure.
+success and NID_undef in case of failure.  Any of I<oid>, I<sn> and
+I<ln> may be NULL, but not all at once.
 
 OBJ_length() returns the size of the content octets of I<obj>.
 

test/asn1_internal_test.c

@@ -190,11 +190,76 @@ static int test_unicode_range(void)
     return ok;
 }
 
+/**********************************************************************
+ *
+ * Tests of object creation
+ *
+ ***/
+
+static int test_obj_create_once(const char *oid, const char *sn, const char *ln)
+{
+    int nid;
+
+    ERR_set_mark();
+
+    nid = OBJ_create(oid, sn, ln);
+
+    if (nid == NID_undef) {
+        unsigned long err = ERR_peek_last_error();
+        int l = ERR_GET_LIB(err);
+        int r = ERR_GET_REASON(err);
+
+        /* If it exists, that's fine, otherwise not */
+        if (l != ERR_LIB_OBJ || r != OBJ_R_OID_EXISTS) {
+            ERR_clear_last_mark();
+            return 0;
+        }
+    }
+    ERR_pop_to_mark();
+    return 1;
+}
+
+static int test_obj_create(void)
+{
+/* Stolen from evp_extra_test.c */
+#define arc "1.3.6.1.4.1.16604.998866."
+#define broken_arc "25."
+#define sn_prefix "custom"
+#define ln_prefix "custom"
+
+    /* Try different combinations of correct object creation */
+    if (!TEST_true(test_obj_create_once(NULL, sn_prefix "1", NULL))
+        || !TEST_int_ne(OBJ_sn2nid(sn_prefix "1"), NID_undef)
+        || !TEST_true(test_obj_create_once(NULL, NULL, ln_prefix "2"))
+        || !TEST_int_ne(OBJ_ln2nid(ln_prefix "2"), NID_undef)
+        || !TEST_true(test_obj_create_once(NULL, sn_prefix "3", ln_prefix "3"))
+        || !TEST_int_ne(OBJ_sn2nid(sn_prefix "3"), NID_undef)
+        || !TEST_int_ne(OBJ_ln2nid(ln_prefix "3"), NID_undef)
+        || !TEST_true(test_obj_create_once(arc "4", NULL, NULL))
+        || !TEST_true(test_obj_create_once(arc "5", sn_prefix "5", NULL))
+        || !TEST_int_ne(OBJ_sn2nid(sn_prefix "5"), NID_undef)
+        || !TEST_true(test_obj_create_once(arc "6", NULL, ln_prefix "6"))
+        || !TEST_int_ne(OBJ_ln2nid(ln_prefix "6"), NID_undef)
+        || !TEST_true(test_obj_create_once(arc "7",
+                                           sn_prefix "7", ln_prefix "7"))
+        || !TEST_int_ne(OBJ_sn2nid(sn_prefix "7"), NID_undef)
+        || !TEST_int_ne(OBJ_ln2nid(ln_prefix "7"), NID_undef))
+        return 0;
+
+    if (!TEST_false(test_obj_create_once(NULL, NULL, NULL))
+        || !TEST_false(test_obj_create_once(broken_arc "8",
+                                            sn_prefix "8", ln_prefix "8")))
+        return 0;
+
+    return 1;
+}
+
 int setup_tests(void)
 {
     ADD_TEST(test_tbl_standard);
     ADD_TEST(test_standard_methods);
     ADD_TEST(test_empty_nonoptional_content);
     ADD_TEST(test_unicode_range);
+    ADD_TEST(test_obj_create);
     return 1;
 }