From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1524531834; cv=none; d=google.com; s=arc-20160816; b=HuVxCjm6RkYSmxzxlxaiML+rx8JS/6bskodR3CL8/LP3nfOKJGjPVoMSnmGGB+nDey 4szX0R1Y83YWggJquFlq2PbBvbAnudN9lK8/Xf1xoVLT5t3/6yZPTB6XJaD8zyZtNT5l EIW8aKvM01M2oHkPaiLAR3TO85brnxpa0ZRjsaCtgbsn2P805bsO62MKK/axIdgBVdDa /pUCGCKpDPWCI8AySdCR5RzFR9XA0jzm0dXvyx4gkz4l1Q/HFbA2iSXU/GxUPNXVxJZa RDfRwCjMN7qQc/KUZUUONvt7qy8GWpLnKdENW/ntE0LyJM3Cidzl0qD0Dihfw5zhKCnb kqhQ== 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=AIWx4S1+D0E92O3VI/N5o1i2947ESe/iMKURvuE2H0s=; b=wYHU6qHImtidiICQY/FSMcUdjpdyvE7zUUYP9EWTXhDQchae+nNb3vR4iLxI+EEZAs w6Dkq7+NrgpgnveXPG0DW80NNl3/jYBcK4IChIDloJAoDNEzcgKdLxnUVEJeMyyWE+YS 4ayYQzC+NZkju6ECF/PsVPVm+Ykc4kckAxUlHNb93YHccqjSGiP3rJpgVUz3MzDjBF90 edt9RkJLIvPEAPhwBSK2SXVNjnReGyaLyfoCY/Awi8TW3MnHerI29pW4pXMp5LxgA7mK zHNO96ZoGAgQkuj5RVEWNe7CT9ljzRY5mp0YkXvngqNv3p3mv4hJdu/aao6Id/iysq7F 3muQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=EHlzkzRu; dkim=pass header.i=@chromium.org header.s=google header.b=STW11T49; spf=pass (google.com: domain of keescook@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=keescook@google.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=chromium.org Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=EHlzkzRu; dkim=pass header.i=@chromium.org header.s=google header.b=STW11T49; spf=pass (google.com: domain of keescook@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=keescook@google.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=chromium.org X-Google-Smtp-Source: AIpwx481MtT20ztPcke186iwa1xb18DpUevfL0bmXdAxQp8bjvb2+7hsIbaIQ8wEZVakldIOgboPJL3Fr3rDHt6aLlo= MIME-Version: 1.0 Sender: keescook@google.com In-Reply-To: References: <1523024546-6150-1-git-send-email-alex.popov@linux.com> <1523024546-6150-3-git-send-email-alex.popov@linux.com> From: Kees Cook Date: Mon, 23 Apr 2018 18:03:51 -0700 X-Google-Sender-Auth: bo0qWU6L7TIsTplgr8YnmlBPDRQ Message-ID: Subject: Re: [PATCH v11 2/6] x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls To: Dave Hansen Cc: Alexander Popov , Ingo Molnar , Laura Abbott , Linus Torvalds , Kernel Hardening , PaX Team , Brad Spengler , Andy Lutomirski , Tycho Andersen , 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 , Florian Weimer , Boris Lukashev , X86 ML , LKML Content-Type: text/plain; charset="UTF-8" X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597007022879408472?= X-GMAIL-MSGID: =?utf-8?q?1598587492365089938?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Wed, Apr 18, 2018 at 11:50 AM, Dave Hansen wrote: > On 04/16/2018 11:29 AM, Kees Cook wrote: >> Dave, Ingo, Linus: how does this look? With the assembly rewritten >> into C, the entry changes are very small: > > The assembly looks very nice to me now. It is as minimally invasive as > it can get. Definitely no objections from me on that part. Can you give an Acked-by for the x86 parts? Or Ingo? If this is workable, I'd like to carry it in -next to see if anything else shakes out... -Kees -- Kees Cook Pixel Security