From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172])
	(using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
	(No client certificate requested)
	by smtp.subspace.kernel.org (Postfix) with ESMTPS id 027FD2F25
	for <llvm@lists.linux.dev>; Sat, 14 May 2022 21:56:51 +0000 (UTC)
Received: by mail-pl1-f172.google.com with SMTP id n18so11114132plg.5
        for <llvm@lists.linux.dev>; Sat, 14 May 2022 14:56:51 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=chromium.org; s=google;
        h=date:from:to:cc:subject:message-id:references:mime-version
         :content-disposition:in-reply-to;
        bh=t9B0ELg8h6PY+Vl2TDucjtXSCma3zXaus6HyZVuhPIE=;
        b=W1eubUSb/5LGT0PX48eWAAjFP3e+45qNMMJH5elMun/Sun50qtQzJU6DnSdp6Eg/+a
         sZUGxqEPzvzsqRpYUlnPpUwqsnDjU3f8F0t6paJwsZDv37wZBcBScTKMeytTqcg+gQ85
         fq0u+JX10bVU5Nl4qNuwnXTR65D2Gmk7mjZv4=
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20210112;
        h=x-gm-message-state:date:from:to:cc:subject:message-id:references
         :mime-version:content-disposition:in-reply-to;
        bh=t9B0ELg8h6PY+Vl2TDucjtXSCma3zXaus6HyZVuhPIE=;
        b=UzEc79j8AjgmtnYhq+y/+BW9R9AHQWOyNxKvlH84T77p76qCcgLZr+RqrnT3keHhho
         DiLaIe0k/hNWGEZypRSPn4/z8Jg2JRc5CwJ5cWE4MfVZ2MdgDyEM+589tIqWbQ+XqCMv
         K6kmwngwufHPXDLXEgGxjve8EXMULoY41pKWBpFR/+xUwfqSw3LVb14s3Gd7JB9wAEH2
         1rXHMrmB3b/9niH2ht/e9D6jQJ2usvY7pJz6KeLu/Rt1MqzawL9qBmtWjbja52Fjf4QL
         NUuMvRGTQ0VthNLFKN5CJ7hWLGyWtteUwc1J2MSVCSRGtoEiBOkhzoVDxmQoZZU/8nNR
         5AaQ==
X-Gm-Message-State: AOAM533SXSOs6O6h8Gr9UFnJ1GRDOI7eieRKGauMUdseWVtaJ8ol2MsE
	8JcyYe2HYv8teHdASBH+AMOsHP6Sovcdxw==
X-Google-Smtp-Source: ABdhPJxYql9CKgnQAH/6nysRco+nTc9rw86pT4JEKLv1mVouDl0G3T6mTm3JsTqv8m6tl1+a5OAhsw==
X-Received: by 2002:a17:90b:4f81:b0:1dc:69a0:432b with SMTP id qe1-20020a17090b4f8100b001dc69a0432bmr22733023pjb.203.1652565411533;
        Sat, 14 May 2022 14:56:51 -0700 (PDT)
Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163])
        by smtp.gmail.com with ESMTPSA id s16-20020a63f050000000b003c14af5060fsm3886055pgj.39.2022.05.14.14.56.51
        (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
        Sat, 14 May 2022 14:56:51 -0700 (PDT)
Date: Sat, 14 May 2022 14:56:50 -0700
From: Kees Cook <keescook@chromium.org>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: linux-kernel@vger.kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>, x86@kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Joao Moreira <joao@overdrivepizza.com>,
	Sedat Dilek <sedat.dilek@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	linux-hardening@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev
Subject: Re: [RFC PATCH v2 15/21] objtool: Don't warn about __cfi_ preambles
 falling through
Message-ID: <202205141456.72950C77B@keescook>
References: <20220513202159.1550547-1-samitolvanen@google.com>
 <20220513202159.1550547-16-samitolvanen@google.com>
Precedence: bulk
X-Mailing-List: llvm@lists.linux.dev
List-Id: <llvm.lists.linux.dev>
List-Subscribe: <mailto:llvm+subscribe@lists.linux.dev>
List-Unsubscribe: <mailto:llvm+unsubscribe@lists.linux.dev>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220513202159.1550547-16-samitolvanen@google.com>

On Fri, May 13, 2022 at 01:21:53PM -0700, Sami Tolvanen wrote:
> The __cfi_ preambles contain valid instructions, which embed KCFI
> type information in the following format:
> 
>   __cfi_function:
>     int3
>     int3
>     mov <id>, %eax
>     int3
>     int3
>   function:
>     ...
> 
> While the preambles are STT_FUNC and contain valid instructions,
> they are not executed and always fall through. Skip the warning for
> them.
> 
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by smtp.lore.kernel.org (Postfix) with ESMTPS id 21230C433F5
	for <linux-arm-kernel@archiver.kernel.org>; Sat, 14 May 2022 21:57:54 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
	d=lists.infradead.org; s=bombadil.20210309; h=Sender:
	Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post:
	List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:
	Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:
	Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:
	List-Owner; bh=Gh0C4MSCz+AAes421nhlyP+/bgy32uaogyBQVw2LX+A=; b=IrYcFpoXiG/Eyw
	K7iXbpalx1CyPhJvu+8z6EqmVL7eLhU9RfOl6IivLqCbxMmadiFWQ2qK/E8uunshIuLE0XgX4INIL
	mq/uH4w9rxtfEcw8hVxuOMg1b/yK+lmG+VKDvPfNm5dbeYaFaLv0AGXDdAW8uNLgvMzAz+SbuZhqM
	Gw0i8wxuXmSDJTw5qJoHdIBU4oNHTPYcrwBVCzxBARGaBwGF+YMSKpPXNjY1h29AZqvaAvtdMPu20
	qz6FNsu/hCgGar1U4yNbsVAcO5yqQkUY/yGIjcuDfRlaU/nuqPZxnTWlZKyOFLKi/erGJEzVxE8Pj
	LfucOuM/DrSk0KurNzEg==;
Received: from localhost ([::1] helo=bombadil.infradead.org)
	by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux))
	id 1npzkx-002PLW-DD; Sat, 14 May 2022 21:56:59 +0000
Received: from mail-pl1-x62a.google.com ([2607:f8b0:4864:20::62a])
 by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux))
 id 1npzkr-002PIv-N3
 for linux-arm-kernel@lists.infradead.org; Sat, 14 May 2022 21:56:54 +0000
Received: by mail-pl1-x62a.google.com with SMTP id j14so11119411plx.3
 for <linux-arm-kernel@lists.infradead.org>;
 Sat, 14 May 2022 14:56:51 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google;
 h=date:from:to:cc:subject:message-id:references:mime-version
 :content-disposition:in-reply-to;
 bh=t9B0ELg8h6PY+Vl2TDucjtXSCma3zXaus6HyZVuhPIE=;
 b=W1eubUSb/5LGT0PX48eWAAjFP3e+45qNMMJH5elMun/Sun50qtQzJU6DnSdp6Eg/+a
 sZUGxqEPzvzsqRpYUlnPpUwqsnDjU3f8F0t6paJwsZDv37wZBcBScTKMeytTqcg+gQ85
 fq0u+JX10bVU5Nl4qNuwnXTR65D2Gmk7mjZv4=
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20210112;
 h=x-gm-message-state:date:from:to:cc:subject:message-id:references
 :mime-version:content-disposition:in-reply-to;
 bh=t9B0ELg8h6PY+Vl2TDucjtXSCma3zXaus6HyZVuhPIE=;
 b=P9Fzo3V+efGmk+pvGA/4QtrzCtbFkeFrbep0wWoryi0A33lip4kslrNjrlhNd/RT+a
 KEhih7hO9IiNnZoLPByOXrbF5hzfbsNsx2yVKJMxIdGqVWMf1wNSo5Pfg4MLnYT6zs+k
 e6sxOA7Pdn/i46DEBMyzVqTC+ZAR2vUq0NpQoVL11s6Os/ig3U3mXhTfUP9YACnhoiv/
 esCc4Meqp3CQCxnjSY421BycUzhHlW0A+HrjKTn5EEtYWsV7awEYj7WgeEzF1OSv3zdk
 sIIRYVBXYSKYujcXy/ZAwk+Ga8wiR1WDWHeY+7RzZ187Ub4rbE+ZdhsanesoCcXFM8/F
 oQrQ==
X-Gm-Message-State: AOAM531BHmtYPc3unxLNSEZDeE7yVjH9WYgEqx7DtE1acZxb5qWnyRRh
 Tzt33d5YLKYOttDZVzyxPPr0nA==
X-Google-Smtp-Source: ABdhPJxYql9CKgnQAH/6nysRco+nTc9rw86pT4JEKLv1mVouDl0G3T6mTm3JsTqv8m6tl1+a5OAhsw==
X-Received: by 2002:a17:90b:4f81:b0:1dc:69a0:432b with SMTP id
 qe1-20020a17090b4f8100b001dc69a0432bmr22733023pjb.203.1652565411533; 
 Sat, 14 May 2022 14:56:51 -0700 (PDT)
Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163])
 by smtp.gmail.com with ESMTPSA id
 s16-20020a63f050000000b003c14af5060fsm3886055pgj.39.2022.05.14.14.56.51
 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
 Sat, 14 May 2022 14:56:51 -0700 (PDT)
Date: Sat, 14 May 2022 14:56:50 -0700
From: Kees Cook <keescook@chromium.org>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: linux-kernel@vger.kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
 Peter Zijlstra <peterz@infradead.org>, x86@kernel.org,
 Catalin Marinas <catalin.marinas@arm.com>,
 Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
 Nathan Chancellor <nathan@kernel.org>,
 Nick Desaulniers <ndesaulniers@google.com>,
 Joao Moreira <joao@overdrivepizza.com>,
 Sedat Dilek <sedat.dilek@gmail.com>, Steven Rostedt <rostedt@goodmis.org>,
 linux-hardening@vger.kernel.org,
 linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev
Subject: Re: [RFC PATCH v2 15/21] objtool: Don't warn about __cfi_ preambles
 falling through
Message-ID: <202205141456.72950C77B@keescook>
References: <20220513202159.1550547-1-samitolvanen@google.com>
 <20220513202159.1550547-16-samitolvanen@google.com>
MIME-Version: 1.0
Content-Disposition: inline
In-Reply-To: <20220513202159.1550547-16-samitolvanen@google.com>
X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 
X-CRM114-CacheID: sfid-20220514_145653_776450_282C1AFB 
X-CRM114-Status: GOOD (  12.12  )
X-BeenThere: linux-arm-kernel@lists.infradead.org
X-Mailman-Version: 2.1.34
Precedence: list
List-Id: <linux-arm-kernel.lists.infradead.org>
List-Unsubscribe: <http://lists.infradead.org/mailman/options/linux-arm-kernel>, 
 <mailto:linux-arm-kernel-request@lists.infradead.org?subject=unsubscribe>
List-Archive: <http://lists.infradead.org/pipermail/linux-arm-kernel/>
List-Post: <mailto:linux-arm-kernel@lists.infradead.org>
List-Help: <mailto:linux-arm-kernel-request@lists.infradead.org?subject=help>
List-Subscribe: <http://lists.infradead.org/mailman/listinfo/linux-arm-kernel>, 
 <mailto:linux-arm-kernel-request@lists.infradead.org?subject=subscribe>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org>
Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org

On Fri, May 13, 2022 at 01:21:53PM -0700, Sami Tolvanen wrote:
> The __cfi_ preambles contain valid instructions, which embed KCFI
> type information in the following format:
> 
>   __cfi_function:
>     int3
>     int3
>     mov <id>, %eax
>     int3
>     int3
>   function:
>     ...
> 
> While the preambles are STT_FUNC and contain valid instructions,
> they are not executed and always fall through. Skip the warning for
> them.
> 
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel