From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f174.google.com (mail-pl1-f174.google.com [209.85.214.174]) (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 C8BB9BA33 for ; Sat, 15 Feb 2025 00:19:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739578759; cv=none; b=A+J78FaWeMEkZtf/5x0H1/1mvDofRU+9W+cM7V3HOluo90jKsSTQtMPkFT1Cb0vb9HTZfTibqEqldZ8no71qYDI4EVFW3/WGv5E50VgsXn7jIcGyl6P7LcwOVgb5E+oupvpMnzGVdLiyiS5Ad3BghrA9UB9xt7iyC/G4SJFv/Fo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739578759; c=relaxed/simple; bh=O2tvnMzyYuYGftivul7qYP6BPi4zhVaLHH+PnG+WSM0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=P3m69k4HCSYY6MNqRgb6oPCJ2aQDxui3xIsKmureRRhFdxQ5Zdayf3wOzUGBMSzDCMC678baqsNN0FGV+GBRd94wwU9uEd7gCDZP0mto39zej187a3QnoV02C4p5i30szjY5GToWNYBuQGvg8NMrurfVFUOFV1aG1nxDr/vN63Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=asu.edu; spf=pass smtp.mailfrom=asu.edu; dkim=pass (2048-bit key) header.d=asu.edu header.i=@asu.edu header.b=bYKfgHOt; arc=none smtp.client-ip=209.85.214.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=asu.edu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=asu.edu Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=asu.edu header.i=@asu.edu header.b="bYKfgHOt" Received: by mail-pl1-f174.google.com with SMTP id d9443c01a7336-220c4159f87so35994425ad.0 for ; Fri, 14 Feb 2025 16:19:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=asu.edu; s=google; t=1739578757; x=1740183557; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=wlkEOzBJttiZYZx0MOJP84lKuZBNzdQhI1Jt7Pa3DyE=; b=bYKfgHOtJ+1woBFj/say+DjvvVoOtF1qWiUoeHJgsxAOc6/et1isAXzFPbJSkR+xo/ bPxFN1NFbcH1cMhkBlwtZgQLxcdaj/5Iy1KmydWBFXEdmk/8DyYBzxBymimS3+uevrhY WVmNwtICTusM8XcZ42yXCvaO6h/qfsMFpJyWu3SBlmvYnv5YdHtZNDezUqESH84FuumP G/SPp5g9dHSJhNjSwp6vY7YHkID+0czXEhQZnvIc0yZYVNQ/mTSgeCfX/OPBBV2Izh0+ 7LkGq3AMAFC9KcojfrPNDSP2ami5ZiRWoDBS41l93V4axxaDjx6eBvN7ThY+/STbYDGL F9XQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739578757; x=1740183557; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=wlkEOzBJttiZYZx0MOJP84lKuZBNzdQhI1Jt7Pa3DyE=; b=wwTREq0p5h0+fn24BzxtU+zgB/fTX8/k+sY8bMfPcureDlCbvMoDoX8jUzLzJ9qbke ArnCoO089oq35HHO8FsNVAExT2zIy6luIMAP3OVCTVKrra3EIUqG/eRtwdGuL/+3l1a9 +RIn77/vHCyBFs5qODG3kZXMNt2DyLmvqXcLfY72O+WrhgU9W/0NfAHNdwgRRfEasx3Q HKqLQAbKvwpJhAgoSJpmlxKKeY/Yzcd5A99rfkeV3KDbIYOX58Vb9fn72K04tSjssCNQ UJh29l5ddCbsrPh7e2sMqCbHMTXfCNfJvezgLlPE8sNP0yJJzcm6xpC+PhPPCQgdCHdw z4qw== X-Forwarded-Encrypted: i=1; AJvYcCXZX5I4D4rPvN6RKacPVpujRU5+ahE3z0riT8KcA8Zzp3DOdLWMrZPlxIhz//uLPxz9djlepyhiQh3TczI=@vger.kernel.org X-Gm-Message-State: AOJu0YzmZdXLVByP9210lbhLgL9bHIPAr9mjTSElwHERmwicZADQDOmD Qxv5reg1dycQ91gVijGDjNGn8v/lpZ8kAwpokAxaxUJgjSx8lSgF+uqYcSMp2g== X-Gm-Gg: ASbGncuP9OcSmS8KKk5u83aSxWVi9jlUCXcbtQjHzwyxjDtHClF/UbXWZ1/gjJNKVS9 KI+FfVqoB9jG+qTY1b90VGT9L1UVTrUxoo/JTb9YSG/RBggUHRl4hVlvXS1qGNtMROkVXbCytZ2 T6Nd2kapyYk8VgyuYdjv3zAPjNU/dknMot9uz64furecJhdxGQ9kgqTePg/l5b8UpeU2j1/4r2P TzgzVKT6dUpdmehB85/eWGPjtKw/yC1xh4cxv1zrLlCRg8WUEug7ZIi8aFSL6ZRsn3sYga0BPYG rQ== X-Google-Smtp-Source: AGHT+IHdV26tckBo8u7d7SukKEJCuBBZmtPNna4QDtQ4xtZWApTjMGnTgqn9ID5uRxOD/BD5vTChew== X-Received: by 2002:a17:903:2f8f:b0:21f:515:d61 with SMTP id d9443c01a7336-22104028a15mr19666095ad.21.1739578756856; Fri, 14 Feb 2025 16:19:16 -0800 (PST) Received: from ubun ([2600:8800:1689:e500:3522:b69b:bf26:8dfb]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-220d53491c9sm34177315ad.15.2025.02.14.16.19.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Feb 2025 16:19:16 -0800 (PST) Date: Fri, 14 Feb 2025 17:19:13 -0700 From: Jennifer Miller To: Andrew Cooper Cc: Jann Horn , Andy Lutomirski , linux-hardening@vger.kernel.org, kees@kernel.org, joao@overdrivepizza.com, samitolvanen@google.com, kernel list Subject: Re: [RFC] Circumventing FineIBT Via Entrypoints Message-ID: References: <60447cd2-a8da-4be6-80fa-a5639b7455b1@citrix.com> <48212481-75ef-43e1-afa1-ec1d603a91a0@citrix.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <48212481-75ef-43e1-afa1-ec1d603a91a0@citrix.com> On Sat, Feb 15, 2025 at 12:11:17AM +0000, Andrew Cooper wrote: > On 15/02/2025 12:07 am, Jennifer Miller wrote: > > On Fri, Feb 14, 2025 at 11:06:50PM +0000, Andrew Cooper wrote: > >> On 13/02/2025 11:24 pm, Jennifer Miller wrote: > >>> On Thu, Feb 13, 2025 at 09:24:18PM +0000, Andrew Cooper wrote: > >>> Still, I hadn't considered misusing readonly/unmapped pages on the GPR > >>> register spill that follows. Could we enforce that the stack pointer we get > >>> be page aligned to prevent this vector? So that if one were to attempt to > >>> point the stack to readonly or unmapped memory they should be guaranteed to > >>> double fault? > >> Hmm. > >> > >> Espfix64 does involve #DF recovering from a write to a read-only stack.  > >> (This broken corner of x86 is also fixed in FRED.   We fixed a *lot* of > >> thing.) > > Interesting, I haven't gotten around to reading into how FRED works, it > > sounds neat. > > Start with > https://docs.google.com/document/d/1hWejnyDkjRRAW-JEsRjA5c9CKLOPc6VKJQsuvODlQEI/edit?usp=sharing > > > Then > https://www.intel.com/content/www/us/en/content-details/779982/flexible-return-and-event-delivery-fred-specification.html > > ~Andrew Thanks, I'll give those a read! ~Jennifer