From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 61B4D214819 for ; Wed, 19 Feb 2025 18:06:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739988360; cv=none; b=EtxOUlIPHMhLvGUXwMmYVZeCoNw75asAVDhdLKxan6y5fJJoZ75S+JBIu+g2lReQ0/nzun6WPYib91+dRI3TU/VhC4/9BZGTVfbMLeYuWSfhKoeLFcquGYo1eNt3+qZcJ3UtdUoJDO8FcTUyTY+xE1xk/2QD2g905sVkhBJXhec= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739988360; c=relaxed/simple; bh=R15E9b7EgxG8lvqI4p1hlUMjMyrN/t+YN4MZxXgBlLk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Hsyftx7RllQmjmD3VKQ5k7YlKrJahvfSSSgjhhZSKFBBsfElNCKZa6iOfI2ibVzDGBQjpm/qhL3N1e1Jyycig326DzuQZcdsZW+tdQhZiIUS0HOcbwrFDPCQ2vtQ2idlRVw9/rTQoIIiAwt4Ixftj46RpmsDeNcX2J5HwVernKQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Rd/obWM7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Rd/obWM7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF10DC4CED1; Wed, 19 Feb 2025 18:05:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739988359; bh=R15E9b7EgxG8lvqI4p1hlUMjMyrN/t+YN4MZxXgBlLk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Rd/obWM7S65TaNeVPJnl7xzEj2AggFx+mTAs/Hwc/i3B6dkQ3xLg7cqO6fdkqk4Bc ZKd2xn4b6tkZQnX+ErImhEpCncSZyKybDDk7hUNCA3xDEy3pWo9F386EuWFknneoJQ wLk4Zv2/vjk003PFr+BsLFKBVz5AmFh4ga/0aT4u5vdOwG6o06LjlHFJCOaRj4Jkfe d3SIVjBm9LVmquODwu6rusXnPuGobCIt32pJZs3a7HLgk+jpqX+bMDJZ010kd9jyHS E8Mwd652nqVSDJ1m/cu1QANCfGQElTkj5E/TdOeEa/RJXVt+PTQlKWpNS7f6Axw881 Osvvrd4H53pdQ== Date: Wed, 19 Feb 2025 10:05:56 -0800 From: Kees Cook To: Peter Zijlstra Cc: x86@kernel.org, linux-kernel@vger.kernel.org, alyssa.milburn@intel.com, scott.d.constable@intel.com, joao@overdrivepizza.com, andrew.cooper3@citrix.com, jpoimboe@kernel.org, jose.marchesi@oracle.com, hjl.tools@gmail.com, ndesaulniers@google.com, samitolvanen@google.com, nathan@kernel.org, ojeda@kernel.org, alexei.starovoitov@gmail.com, mhiramat@kernel.org, jmill@asu.edu Subject: Re: [PATCH v3 07/10] x86/ibt: Add paranoid FineIBT mode Message-ID: <202502191005.11B95F4CB8@keescook> References: <20250219162107.880673196@infradead.org> <20250219163515.040300905@infradead.org> 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=us-ascii Content-Disposition: inline In-Reply-To: <20250219163515.040300905@infradead.org> On Wed, Feb 19, 2025 at 05:21:14PM +0100, Peter Zijlstra wrote: > Due to concerns about circumvention attacks against FineIBT on 'naked' > ENDBR, add an additional caller side hash check to FineIBT. This > should make it impossible to pivot over such a 'naked' ENDBR > instruction at the cost of an additional load. > > The specific pivot reported was against the SYSCALL entry site and > FRED will have all those holes fixed up. > > This specific fineibt_paranoid_start[] sequence was concocted by > Scott. > > Reported-by: Jennifer Miller > Signed-off-by: Peter Zijlstra (Intel) With patch 6's misplaced chunk moved, looks good: Reviewed-by: Kees Cook -- Kees Cook