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From: Kent Overstreet To: Matthew Wilcox Cc: Kees Cook , Andrew Morton , Suren Baghdasaryan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH] alloc_tag: Tighten file permissions on /proc/allocinfo Message-ID: References: <20240425200844.work.184-kees@kernel.org> <64cngpnwyav4odustofs6hgsh7htpc5nu23tx4lb3vxaltmqf2@sxn63f2gg4gu> <202404251532.F8860056AE@keescook> <20240425164718.e8e187dd0c5b0a87371d8316@linux-foundation.org> <202404251740.81F21E54@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: B58B84000D X-Rspam-User: X-Stat-Signature: ijpa6jnhwycc1h9a5fpxmt4y3p31magn X-HE-Tag: 1714102562-756058 X-HE-Meta: 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 c7nws1tG Toi5hacZ926YWZLilp6n3Tzw+KKuHoePpHDMuAwmEgN6maLEl534ZGpSgmP3rmxrvV032eqOc6gOC+5mAf15ZwzSdSUSZDKqDz9lsbXLKXXJ4GJh65EW4JGE4+FsK1DX6XXFd X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Apr 26, 2024 at 04:25:40AM +0100, Matthew Wilcox wrote: > On Thu, Apr 25, 2024 at 08:58:34PM -0400, Kent Overstreet wrote: > > On Thu, Apr 25, 2024 at 05:43:33PM -0700, Kees Cook wrote: > > > All this said, I'm still not excited about any of these files living > > > in /proc at all -- we were supposed to use /sys for this kind of thing, > > > but its interface wasn't great for this kind of more "free-form" data, > > > and debugfs isn't good for production interfaces. /proc really should > > > only have pid information -- we end up exposing these top-level files to > > > every mount namespace with a /proc mount. :( But that's a yet-to-be-solved > > > problem... > > > > It really wouldn't be that hard to relax the 4k file limit in sysfs. > > It's a lot harder to relax the GregKH opposition to multiple values per > file in sysfs. Which makes no sense for columnar data.