From: Kees Cook <keescook@chromium.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Erick Archer <erick.archer@outlook.com>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
"Liang, Kan" <kan.liang@linux.intel.com>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
Justin Stitt <justinstitt@google.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH] perf/ring_buffer: Prefer struct_size over open coded arithmetic
Date: Thu, 2 May 2024 15:55:36 -0700 [thread overview]
Message-ID: <202405021552.5C000EA@keescook> (raw)
In-Reply-To: <20240502091837.GA30852@noisy.programming.kicks-ass.net>
On Thu, May 02, 2024 at 11:18:37AM +0200, Peter Zijlstra wrote:
> On Wed, May 01, 2024 at 01:21:42PM -0700, Kees Cook wrote:
> > On Tue, Apr 30, 2024 at 11:15:04AM +0200, Peter Zijlstra wrote:
> > > On Mon, Apr 29, 2024 at 07:40:58PM +0200, Erick Archer wrote:
> > > > This is an effort to get rid of all multiplications from allocation
> > > > functions in order to prevent integer overflows [1][2].
> > >
> > > So personally I detest struct_size() because I can never remember wtf it
> > > does, whereas the code it replaces is simple and straight forward :/
> >
> > Sure, new APIs can involved a learning curve. If we can all handle
> > container_of(), we can deal with struct_size(). :)
>
> containre_of() is actually *much* shorter than typing it all out. Which
> is a benefit.
>
> struct_size() not so much. That's just obfuscation for obfuscation's
> sake.
It's really not -- it's making sure that the calculation is semantically
sane: all the right things are being used for the struct size calculation
and things can't "drift", if types change, flex array changes, etc. It's
both a code robustness improvement and a wrap-around stopping improvement.
--
Kees Cook
next prev parent reply other threads:[~2024-05-02 22:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-29 17:40 [PATCH] perf/ring_buffer: Prefer struct_size over open coded arithmetic Erick Archer
2024-04-29 18:23 ` Kees Cook
2024-04-30 9:15 ` Peter Zijlstra
2024-05-01 17:23 ` Erick Archer
2024-05-01 20:21 ` Kees Cook
2024-05-02 9:18 ` Peter Zijlstra
2024-05-02 22:55 ` Kees Cook [this message]
2024-05-04 17:21 ` Erick Archer
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