From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95E1EC433F5 for ; Wed, 8 Sep 2021 21:26:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 70A1B6113C for ; Wed, 8 Sep 2021 21:26:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349865AbhIHV1O (ORCPT ); Wed, 8 Sep 2021 17:27:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231956AbhIHV1O (ORCPT ); Wed, 8 Sep 2021 17:27:14 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C205C061575 for ; Wed, 8 Sep 2021 14:26:06 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id 88DEB6CD0; Wed, 8 Sep 2021 17:26:05 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 88DEB6CD0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1631136365; bh=lwLbs160re0AuNnzwL9YajBsZwg0P/fJ7LxV8NwO//o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dr3jKJUyGUPG2dPSrEBcjOVk4Y3/QKRNtLKWqqlXt0l2EhcWhi1hX90JGEPV9Qxyb 5AwlQU8KR3EXWgrGeJuGMiSYF5bUfPixnNqTR2MBSlxQ5tpdod7fM78uQTJXEFX93V TgggJmkmyt961RAQcASGZW00x4/5RWE3Tk6rkC4A= Date: Wed, 8 Sep 2021 17:26:05 -0400 From: Bruce Fields To: Chuck Lever III Cc: Jeff Layton , Dan Carpenter , Linux NFS Mailing List Subject: Re: [bug report] nfsd: Protect session creation and client confirm using client_lock Message-ID: <20210908212605.GF23978@fieldses.org> References: <20210907080732.GA20341@kili> <622EC724-ECBF-424D-A003-46A6B8E8C215@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <622EC724-ECBF-424D-A003-46A6B8E8C215@oracle.com> User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Tue, Sep 07, 2021 at 03:00:23PM +0000, Chuck Lever III wrote: > We have IPV6_SCOPE_ID_LEN as a maximum size of the scope ID, > and it's not a big value. As long as boundary checking is made > to be sufficient, then a stack residency for the device name > should be safe. Something like this? (Or are you making a patch? I'm not even sure how to test.) --b. diff --git a/net/sunrpc/addr.c b/net/sunrpc/addr.c index 6e4dbd577a39..d435bffc6199 100644 --- a/net/sunrpc/addr.c +++ b/net/sunrpc/addr.c @@ -162,8 +162,10 @@ static int rpc_parse_scope_id(struct net *net, const char *buf, const size_t buflen, const char *delim, struct sockaddr_in6 *sin6) { - char *p; + char p[IPV6_SCOPE_ID_LEN + 1]; size_t len; + u32 scope_id = 0; + struct net_device *dev; if ((buf + buflen) == delim) return 1; @@ -175,29 +177,23 @@ static int rpc_parse_scope_id(struct net *net, const char *buf, return 0; len = (buf + buflen) - delim - 1; - p = kmemdup_nul(delim + 1, len, GFP_KERNEL); - if (p) { - u32 scope_id = 0; - struct net_device *dev; - - dev = dev_get_by_name(net, p); - if (dev != NULL) { - scope_id = dev->ifindex; - dev_put(dev); - } else { - if (kstrtou32(p, 10, &scope_id) != 0) { - kfree(p); - return 0; - } - } - - kfree(p); - - sin6->sin6_scope_id = scope_id; - return 1; + if (len > IPV6_SCOPE_ID_LEN) + return 0; + + memcpy(p, delim + 1, len); + p[len] = 0; + + dev = dev_get_by_name(net, p); + if (dev != NULL) { + scope_id = dev->ifindex; + dev_put(dev); + } else { + if (kstrtou32(p, 10, &scope_id) != 0) + return 0; } - return 0; + sin6->sin6_scope_id = scope_id; + return 1; } static size_t rpc_pton6(struct net *net, const char *buf, const size_t buflen,