From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1520280912; cv=none; d=google.com; s=arc-20160816; b=WhkCYhBVStc/UOGszypDjHAXfWFg3CTGR+OkCPp78hfyxUKZDC8gWH4ZHBCbAvq0I0 TgaD4e6EBNfVi43HdDPolVRQvvlD0mDZVAslHre8Z5H0uzB+etQrs5mzXDwe29N60EGi zXtVj0HNxE86dkUneeJgrSdMQzFvWh894QBWOHiwLFo5A5Muz2xoW2QajTzaOP62UId2 CgiAFphzviV6F08DWqUkhLP9SKVT3B8yCu+ebwKRJkXVxgX19sKEeBVeqgNDlUhz+Km6 65ecreTrOzPJ1+EDGQX/l/ltap4R4oSbpylMtmA2xTHBV4tLmJqqnzVfVOYtfvZy6UwK Oaow== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:references:in-reply-to:sender :mime-version:dkim-signature:dkim-signature :arc-authentication-results; bh=Wc1jPfby70Fqn0+j3ceqF9a49SCFg3tHX2IbKKfRbKI=; b=CmbzA5F1sI4zna+zmcK/h8CTTqh0zcbA2NrkIoNe3OOpEetlCQ+uDeDuHwJsthg6Sm 21i11G3lKCyGSl36gcahEcYOSetiuqlCwDy9StBTHK9RnJYuuoMQuxdUG9nMDLdqzCQW oGe35mjEHVFtKKmecrxRMW0f9Nj8TBUg2X8zd/aG/0Y3fWrIVOC8AUA3xyd9kKKI+DcT aKddN6Jr+Y0m9OiIewDSam+cuzT/EBBxr06cbx6u1G8NTOTi6khKUMwZPYW3DuIKa+hT E+guoUtySePhUBjegUfLKhvrZ4MuW2vjLw6g5c43Z++Ahs6STlGjbl7ZYcFWtB4rBDct dtvg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=e7pRKw4x; dkim=pass header.i=@linux-foundation.org header.s=google header.b=fX11RXtR; spf=pass (google.com: domain of linus971@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=linus971@gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=e7pRKw4x; dkim=pass header.i=@linux-foundation.org header.s=google header.b=fX11RXtR; spf=pass (google.com: domain of linus971@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=linus971@gmail.com X-Google-Smtp-Source: AG47ELuV5Diaz4qKJ2v4a4UGXQPvfR5ACaeHd0TaXxwajsZvAvE4xe4z7/k1Agv1jpx6TVbO8kLNE2gkC6IobRfK6nY= MIME-Version: 1.0 Sender: linus971@gmail.com In-Reply-To: References: <1520107232-14111-1-git-send-email-alex.popov@linux.com> <1520107232-14111-5-git-send-email-alex.popov@linux.com> From: Linus Torvalds Date: Mon, 5 Mar 2018 12:15:11 -0800 X-Google-Sender-Auth: 2jvvQ3QMRExl8dtDrBW9kARJOwU Message-ID: Subject: Re: [PATCH RFC v9 4/7] x86/entry: Erase kernel stack in syscall_trace_enter() To: Kees Cook Cc: Dave Hansen , Alexander Popov , Kernel Hardening , PaX Team , Brad Spengler , Ingo Molnar , Andy Lutomirski , Tycho Andersen , Laura Abbott , Mark Rutland , Ard Biesheuvel , Borislav Petkov , Richard Sandiford , Thomas Gleixner , "H . Peter Anvin" , Peter Zijlstra , "Dmitry V . Levin" , Emese Revfy , Jonathan Corbet , Andrey Ryabinin , "Kirill A . Shutemov" , Thomas Garnier , Andrew Morton , Alexei Starovoitov , Josef Bacik , Masami Hiramatsu , Nicholas Piggin , Al Viro , "David S . Miller" , Ding Tianhong , David Woodhouse , Josh Poimboeuf , Steven Rostedt , Dominik Brodowski , Juergen Gross , Greg Kroah-Hartman , Dan Williams , Mathias Krause , Vikas Shivappa , Kyle Huey , Dmitry Safonov , Will Deacon , Arnd Bergmann , X86 ML , LKML Content-Type: text/plain; charset="UTF-8" X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1593947986518331727?= X-GMAIL-MSGID: =?utf-8?q?1594130078382182751?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: This is the first I see of any of this, it was apparently not actually posted to lkml or anything like that. Honestly, what I see just makes me go "this is security-masturbation". It doesn't actually seem to help *find* bugs at all. As such, it's another "paper over and forget" thing that just adds fairly high overhead when it's enabled. I'm NAK'ing it sight-unseen (see above) just because I'm tired of these kinds of pointless things that don't actually strive to improve on the kernel, just add more and more overhead for nebulous "things may happen", and that just make the code uglier. Why wasn't it even posted to lkml? And why isn't the focus of security people on tools to _analyse_ and find problems? Linus