From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f47.google.com (mail-wg0-f47.google.com [74.125.82.47]) by kanga.kvack.org (Postfix) with ESMTP id 749996B0036 for ; Fri, 8 Aug 2014 13:12:18 -0400 (EDT) Received: by mail-wg0-f47.google.com with SMTP id b13so5729794wgh.6 for ; Fri, 08 Aug 2014 10:12:17 -0700 (PDT) Received: from mail-we0-x22f.google.com (mail-we0-x22f.google.com [2a00:1450:400c:c03::22f]) by mx.google.com with ESMTPS id h1si12630307wjw.67.2014.08.08.10.12.16 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 08 Aug 2014 10:12:16 -0700 (PDT) Received: by mail-we0-f175.google.com with SMTP id t60so5966702wes.20 for ; Fri, 08 Aug 2014 10:12:16 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20140808075316.GA21919@www.outflux.net> References: <20140808075316.GA21919@www.outflux.net> From: Dan Streetman Date: Fri, 8 Aug 2014 13:11:55 -0400 Message-ID: Subject: Re: [PATCH] mm/zpool: use prefixed module loading Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Kees Cook Cc: linux-kernel , Seth Jennings , Minchan Kim , Nitin Gupta , Andrew Morton , Dan Carpenter , Linux-MM On Fri, Aug 8, 2014 at 3:53 AM, Kees Cook wrote: > To avoid potential format string expansion via module parameters, > do not use the zpool type directly in request_module() without a > format string. Additionally, to avoid arbitrary modules being loaded > via zpool API (e.g. via the zswap_zpool_type module parameter) add a > "zpool-" prefix to the requested module, as well as module aliases for > the existing zpool types (zbud and zsmalloc). > > Signed-off-by: Kees Cook > --- > mm/zbud.c | 1 + > mm/zpool.c | 2 +- > mm/zsmalloc.c | 1 + > 3 files changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/zbud.c b/mm/zbud.c > index a05790b1915e..aa74f7addab1 100644 > --- a/mm/zbud.c > +++ b/mm/zbud.c > @@ -619,3 +619,4 @@ module_exit(exit_zbud); > MODULE_LICENSE("GPL"); > MODULE_AUTHOR("Seth Jennings "); > MODULE_DESCRIPTION("Buddy Allocator for Compressed Pages"); > +MODULE_ALIAS("zpool-zbud"); If we keep this, I'd recommend putting this inside the #ifdef CONFIG_ZPOOL section, to keep all the zpool stuff together in zbud and zsmalloc. > diff --git a/mm/zpool.c b/mm/zpool.c > index e40612a1df00..739cdf0d183a 100644 > --- a/mm/zpool.c > +++ b/mm/zpool.c > @@ -150,7 +150,7 @@ struct zpool *zpool_create_pool(char *type, gfp_t gfp, struct zpool_ops *ops) > driver = zpool_get_driver(type); > > if (!driver) { > - request_module(type); > + request_module("zpool-%s", type); I agree with a change of (type) to ("%s", type), but what's the need to prefix "zpool-"? Anyone who has access to modify the zswap_zpool_type parameter is already root and can just as easily load any module they want. Additionally, the zswap_compressor parameter also runs through request_module() (in crypto/api.c) and could be used to load any kernel module. I'd prefer to leave out the "zpool-" prefix unless there is a specific reason to include it. > driver = zpool_get_driver(type); > } > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index 4e2fc83cb394..36af729eb3f6 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -1199,3 +1199,4 @@ module_exit(zs_exit); > > MODULE_LICENSE("Dual BSD/GPL"); > MODULE_AUTHOR("Nitin Gupta "); > +MODULE_ALIAS("zpool-zsmalloc"); > -- > 1.9.1 > > > -- > Kees Cook > Chrome OS Security > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org