From: Chao Yu <yuchao0@huawei.com> To: Jaegeuk Kim <jaegeuk@kernel.org> Cc: <linux-f2fs-devel@lists.sourceforge.net>, <linux-kernel@vger.kernel.org>, <chao@kernel.org> Subject: Re: [PATCH] f2fs: set deadline to drop expired inmem pages Date: Fri, 13 Apr 2018 09:25:37 +0800 [thread overview] Message-ID: <bb7d3b60-0629-ea80-c4ae-976a76abb034@huawei.com> (raw) In-Reply-To: <20180413010433.GB51348@jaegeuk-macbookpro.roam.corp.google.com> On 2018/4/13 9:04, Jaegeuk Kim wrote: > On 04/10, Chao Yu wrote: >> Hi Jaegeuk, >> >> On 2018/4/8 16:13, Chao Yu wrote: >>> f2fs doesn't allow abuse on atomic write class interface, so except >>> limiting in-mem pages' total memory usage capacity, we need to limit >>> start-commit time as well, otherwise we may run into infinite loop >>> during foreground GC because target blocks in victim segment are >>> belong to atomic opened file for long time. >>> >>> Now, we will check the condition with f2fs_balance_fs_bg in >>> background threads, once if user doesn't commit data exceeding 30 >>> seconds, we will drop all cached data, so I expect it can keep our >>> system running safely to prevent Dos attack. >> >> Is it worth to add this patch to avoid abuse on atomic write interface by user? > > Hmm, hope to see a real problem first in this case. I think this can be a more critical security leak instead of a potential issue which we can wait for someone reporting that can be too late. For example, user can simply write a huge file whose data spread in all f2fs segments, once user open that file as atomic, foreground GC will suffer deadloop, causing denying any further service of f2fs. Thanks, > >> Thanks, > > . >
WARNING: multiple messages have this Message-ID (diff)
From: Chao Yu <yuchao0@huawei.com> To: Jaegeuk Kim <jaegeuk@kernel.org> Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [PATCH] f2fs: set deadline to drop expired inmem pages Date: Fri, 13 Apr 2018 09:25:37 +0800 [thread overview] Message-ID: <bb7d3b60-0629-ea80-c4ae-976a76abb034@huawei.com> (raw) In-Reply-To: <20180413010433.GB51348@jaegeuk-macbookpro.roam.corp.google.com> On 2018/4/13 9:04, Jaegeuk Kim wrote: > On 04/10, Chao Yu wrote: >> Hi Jaegeuk, >> >> On 2018/4/8 16:13, Chao Yu wrote: >>> f2fs doesn't allow abuse on atomic write class interface, so except >>> limiting in-mem pages' total memory usage capacity, we need to limit >>> start-commit time as well, otherwise we may run into infinite loop >>> during foreground GC because target blocks in victim segment are >>> belong to atomic opened file for long time. >>> >>> Now, we will check the condition with f2fs_balance_fs_bg in >>> background threads, once if user doesn't commit data exceeding 30 >>> seconds, we will drop all cached data, so I expect it can keep our >>> system running safely to prevent Dos attack. >> >> Is it worth to add this patch to avoid abuse on atomic write interface by user? > > Hmm, hope to see a real problem first in this case. I think this can be a more critical security leak instead of a potential issue which we can wait for someone reporting that can be too late. For example, user can simply write a huge file whose data spread in all f2fs segments, once user open that file as atomic, foreground GC will suffer deadloop, causing denying any further service of f2fs. Thanks, > >> Thanks, > > . > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
next prev parent reply other threads:[~2018-04-13 1:25 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-04-08 8:13 [PATCH] f2fs: set deadline to drop expired inmem pages Chao Yu 2018-04-08 8:13 ` Chao Yu 2018-04-10 7:38 ` Chao Yu 2018-04-10 7:38 ` Chao Yu 2018-04-13 1:04 ` Jaegeuk Kim 2018-04-13 1:25 ` Chao Yu [this message] 2018-04-13 1:25 ` Chao Yu 2018-04-13 4:05 ` Jaegeuk Kim 2018-04-13 6:08 ` Chao Yu 2018-04-13 6:08 ` Chao Yu 2018-04-16 20:16 ` Jaegeuk Kim 2018-04-17 6:44 ` Chao Yu 2018-04-17 6:44 ` Chao Yu 2018-04-17 11:45 ` Chao Yu 2018-04-17 11:45 ` Chao Yu 2018-04-18 4:14 ` Jaegeuk Kim
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