From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f175.google.com (mail-pl1-f175.google.com [209.85.214.175]) (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 361A3548E6 for ; Tue, 5 Mar 2024 10:12:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709633549; cv=none; b=IGDcvLbSlOtSBugmX52HkaY8cTYoPaDuHb0NDMZMcadXBptdvef1QutbXnAFh26pA/B+G8hMCuP9BQ8kwXbpHUV0APfnHXK657gz1yEr1VBQpvg4kKTaKuT5nef/dznd1F4AAp8Ur1mc3u3EdTI7gSW3KBAhdfs7NxkCQWWX3UQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709633549; c=relaxed/simple; bh=qX84Qr8Rjx3k1Qrrec1tOKVgxK5Rdtm5/Yv88GrB3xM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=p0XVn1ECQ1M6tNqj9+rUZHZw4mA2dejL8kb0ykoryXx20JT3IexklV7/s+wfr6tJ9UYiRusU0LUY5GPmoYPhub6gEGOjKK/hysK+qywO3C4ldDzT8DIAp0In+eCOXbJ+nCurFT7BsYyT3F5F1tmMGyfMEUn4jZi0TVoFp5wITOU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=gT9lMjiE; arc=none smtp.client-ip=209.85.214.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="gT9lMjiE" Received: by mail-pl1-f175.google.com with SMTP id d9443c01a7336-1dd178fc492so13819845ad.2 for ; Tue, 05 Mar 2024 02:12:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1709633547; x=1710238347; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=90GoPmdoNB7qy/Rz4aKAQpu8I3w30a6c5BBckmqB0YE=; b=gT9lMjiETrAheaS14Ym8qIZ1UybbiLc8FoP+cq4pXprpgq/K3ae6Hyavcrr8ezOnEf EwlHVc5SET4LNV4m+8tMcvR3Zo/b4atkP34fMI3c2vMsw4bzu4er7OssbexTHiQy/VDR vW9HcMeHMi4+K2iC4Vwe57ZpMV6TfQjgCtOeM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709633547; x=1710238347; h=in-reply-to: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=90GoPmdoNB7qy/Rz4aKAQpu8I3w30a6c5BBckmqB0YE=; b=RJRaTmJnfs0KHNeRqIiYh8wxb77G4+PCkJ50g5PsefmiljlrtmUFr9nx0LhGXWPCYT o/fTiO1zIaq19Qr87N3H8TaoXjgSJ9N2b4xuWuxR4szi9BKRtDHg0ZiZ1doMDxBEalAi wrLolPknBFNSPVS2B9RqFO0kG2MjgpTdcfMy1AExqSjTY7VS8dBJHll49yTFc1wlaEJ6 7ob2pV/fIILibsYx2pIWBG67YZChn10faniJS+myyK8wV5F8lMnCEadq4daxpsUVsbY4 4PjD5i8+fKftQEUotFee8WlqrWqRFTmRymOTpYRSuhmC/n/QBqTCg79DCdrHHfpTb4qt 3MIQ== X-Forwarded-Encrypted: i=1; AJvYcCU2zRCR/RV6lavMF4LH081z9UHC7iTyWhw00lRPhCJF+1mc4GiXRhaKUUnySga1KjcmlCwtf94b5xakV9Uh2pY3ErcGYp2nF+eN X-Gm-Message-State: AOJu0YwHrilJsEG3EFg1bfzOOpBreVwVhl1VPpuKn/Nq7H5HB+xOwM2x HraSN3yt2+zijlqx0RW3+5V6qPFbftvIy5YmuJDYyC9lQpSQlmvh4kwg96DOXw== X-Google-Smtp-Source: AGHT+IHivF51UPX1N5OEzkfKJUGVPso4IRPc5xLAaCXRGUd0otijzh2wsjGTeXcfAY79j5YppLpA7g== X-Received: by 2002:a17:902:8a83:b0:1d7:2e86:fb2a with SMTP id p3-20020a1709028a8300b001d72e86fb2amr1109359plo.65.1709633547547; Tue, 05 Mar 2024 02:12:27 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id mm12-20020a1709030a0c00b001dc96d1a662sm10134092plb.197.2024.03.05.02.12.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Mar 2024 02:12:26 -0800 (PST) Date: Tue, 5 Mar 2024 02:12:26 -0800 From: Kees Cook To: Christian Brauner Cc: Adrian Ratiu , linux-fsdevel@vger.kernel.org, kernel@collabora.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Guenter Roeck , Doug Anderson , Jann Horn , Andrew Morton , Randy Dunlap , Mike Frysinger Subject: Re: [PATCH v2] proc: allow restricting /proc/pid/mem writes Message-ID: <202403050211.86A44769@keescook> References: <20240301213442.198443-1-adrian.ratiu@collabora.com> <20240304-zugute-abtragen-d499556390b3@brauner> <202403040943.9545EBE5@keescook> <20240305-attentat-robust-b0da8137b7df@brauner> <202403050134.784D787337@keescook> <20240305-kontakt-ticken-77fc8f02be1d@brauner> Precedence: bulk X-Mailing-List: linux-doc@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: <20240305-kontakt-ticken-77fc8f02be1d@brauner> On Tue, Mar 05, 2024 at 10:58:25AM +0100, Christian Brauner wrote: > Since the write handler for /proc//mem does raise FOLL_FORCE > unconditionally it likely would implicitly. But I'm not familiar enough > with FOLL_FORCE to say for sure. I should phrase the question better. :) Is the supervisor writing into read-only regions of the child process? -- Kees Cook