do_dirname: Don't change gen on failures

It would set gen->d.dirn to a freed pointer in case X509V3_NAME_from_section
failed.
Reviewed-by: NRich Salz <rsalz@openssl.org>

crypto/x509v3/v3_alt.c

@@ -586,24 +586,26 @@ static int do_othername(GENERAL_NAME *gen, char *value, X509V3_CTX *ctx)
 
 static int do_dirname(GENERAL_NAME *gen, char *value, X509V3_CTX *ctx)
 {
-    int ret;
-    STACK_OF(CONF_VALUE) *sk;
-    X509_NAME *nm;
+    int ret = 0;
+    STACK_OF(CONF_VALUE) *sk = NULL;
+    X509_NAME *nm = NULL;
     if (!(nm = X509_NAME_new()))
-        return 0;
+        goto err;
     sk = X509V3_get_section(ctx, value);
     if (!sk) {
         X509V3err(X509V3_F_DO_DIRNAME, X509V3_R_SECTION_NOT_FOUND);
         ERR_add_error_data(2, "section=", value);
-        X509_NAME_free(nm);
-        return 0;
+        goto err;
     }
     /* FIXME: should allow other character types... */
     ret = X509V3_NAME_from_section(nm, sk, MBSTRING_ASC);
     if (!ret)
-        X509_NAME_free(nm);
+        goto err;
     gen->d.dirn = nm;
-    X509V3_section_free(ctx, sk);
 
+err:
+    if (ret == 0)
+        X509_NAME_free(nm);
+    X509V3_section_free(ctx, sk);
     return ret;
 }