From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail3-relais-sop.national.inria.fr (mail3-relais-sop.national.inria.fr [192.134.164.104]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6F71D17CA for ; Sun, 15 Oct 2023 04:53:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=inria.fr Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=inria.fr Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=inria.fr header.i=@inria.fr header.b="k5IQxBjX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=inria.fr; s=dc; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=fMGwmeCiI2WGZSSIY9zDXk4JfSuYvkdAr36FIasOYjU=; b=k5IQxBjXGV3CnXmP7VgfiaoFeBhRXdFbvwWcEJ86HrDH2aegcMqgy9/b I9LI0HC1txkCq9sNogIroruo9K0Hh9y5ZrXnsAxRar8tN2v4I3LVDbRSv x6yt7j8E7k1e7EcOSnJOckIDAkgHN9kLA1i0nOA4E0PtLe9QlrFZZ21U9 w=; Authentication-Results: mail3-relais-sop.national.inria.fr; dkim=none (message not signed) header.i=none; spf=SoftFail smtp.mailfrom=julia.lawall@inria.fr; dmarc=fail (p=none dis=none) d=inria.fr X-IronPort-AV: E=Sophos;i="6.03,226,1694728800"; d="scan'208";a="68734435" Received: from 231.85.89.92.rev.sfr.net (HELO hadrien) ([92.89.85.231]) by mail3-relais-sop.national.inria.fr with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Oct 2023 06:53:30 +0200 Date: Sun, 15 Oct 2023 06:53:29 +0200 (CEST) From: Julia Lawall X-X-Sender: jll@hadrien To: Kees Cook cc: Christophe JAILLET , Pravin B Shelar , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , "Gustavo A. R. Silva" , Nathan Chancellor , Nick Desaulniers , Tom Rix , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, netdev@vger.kernel.org, dev@openvswitch.org, linux-hardening@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH v2 2/2] net: openvswitch: Annotate struct mask_array with __counted_by In-Reply-To: <202310141928.23985F1CA@keescook> Message-ID: References: <202310141928.23985F1CA@keescook> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Sat, 14 Oct 2023, Kees Cook wrote: > On Sat, Oct 14, 2023 at 08:34:53AM +0200, Christophe JAILLET wrote: > > Prepare for the coming implementation by GCC and Clang of the __counted_by > > attribute. Flexible array members annotated with __counted_by can have > > their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS > > (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family > > functions). > > > > Signed-off-by: Christophe JAILLET > > --- > > v2: Fix the subject [Ilya Maximets] > > fix the field name used with __counted_by [Ilya Maximets] > > > > v1: https://lore.kernel.org/all/f66ddcf1ef9328f10292ea75a17b584359b6cde3.1696156198.git.christophe.jaillet@wanadoo.fr/ > > > > > > This patch is part of a work done in parallel of what is currently worked > > on by Kees Cook. > > > > My patches are only related to corner cases that do NOT match the > > semantic of his Coccinelle script[1]. What was the problem with the semantic patch in this case? thanks, julia > > > > In this case, in tbl_mask_array_alloc(), several things are allocated with > > a single allocation. Then, some pointer arithmetic computes the address of > > the memory after the flex-array. > > > > [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci > > --- > > net/openvswitch/flow_table.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/net/openvswitch/flow_table.h b/net/openvswitch/flow_table.h > > index 9e659db78c05..f524dc3e4862 100644 > > --- a/net/openvswitch/flow_table.h > > +++ b/net/openvswitch/flow_table.h > > @@ -48,7 +48,7 @@ struct mask_array { > > int count, max; > > struct mask_array_stats __percpu *masks_usage_stats; > > u64 *masks_usage_zero_cntr; > > - struct sw_flow_mask __rcu *masks[]; > > + struct sw_flow_mask __rcu *masks[] __counted_by(max); > > }; > > Yup, this looks correct to me. Thanks! > > Reviewed-by: Kees Cook > > -- > Kees Cook >