From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1B6AC4320E for ; Sat, 28 Aug 2021 21:48:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5A2A560E93 for ; Sat, 28 Aug 2021 21:48:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5A2A560E93 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id C367E6B006C; Sat, 28 Aug 2021 17:48:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BE6A76B0071; Sat, 28 Aug 2021 17:48:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AD4B88D0001; Sat, 28 Aug 2021 17:48:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0241.hostedemail.com [216.40.44.241]) by kanga.kvack.org (Postfix) with ESMTP id 9EAEA6B006C for ; Sat, 28 Aug 2021 17:48:00 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id C876C8249980 for ; Sat, 28 Aug 2021 21:47:58 +0000 (UTC) X-FDA: 78525827436.24.262A1FA Received: from mail-yb1-f182.google.com (mail-yb1-f182.google.com [209.85.219.182]) by imf13.hostedemail.com (Postfix) with ESMTP id 88E95101EA63 for ; Sat, 28 Aug 2021 21:47:58 +0000 (UTC) Received: by mail-yb1-f182.google.com with SMTP id q70so19833815ybg.11 for ; Sat, 28 Aug 2021 14:47:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=rpFNOvvpFZbbZ8OM3mIkAwJTup8tfISROOVfntRP9pg=; b=MzSuWBFZvekJz7MBaisKxWQ6esuYjymMLZ3IrbKj/oha3c6TmcvZtOeOIvOrR0wk2r MI9IE8qYkuhDL3mVBGpQokgXbf1Sv32wrg2D7tpw1KBPbBl3CB8uFDsLUOjqrUV/iwMY nqabwDzlrPvZEeWxcCs7/3Ir1zqLdAbIh9MRwdZPG8JpUj8Hgp78xJfy875BU05RAcIj nK52sQVxzEGZiKl8GtQxwYiDr9brpS4Dzsrj5U+TxePlIxTM2Hr4e/T7peehxfrkda/c 0J+Z1AYZjUNYWGlJ90k16GfxTYfDUZ2hpZCjn43GkToyMAk89/Ye7WqaU1WQLL5TKU9d 3Q+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=rpFNOvvpFZbbZ8OM3mIkAwJTup8tfISROOVfntRP9pg=; b=mjf+5dA5dRjaSJi4GDodt8rOO7rxqeloS4HkQBik67qStmE1dLYJZt8JVLnnd5ah+3 0rNbydhZAholf9AAz65NiB/DYGUzT28yvPaOamKxkxtCP/2H2mn9799Iok+TIgUwiR9N UkZ0EjQzgGM5yxirmPQzNuzaUjdNoc8PU8qixQJjGixBOaV5VIg07DP1lLtkOrCQK4ta hDtNPch+jbUX/Hu8iClMLXHR069A88sPH4FWbmiPzeJzuVbFh2xIH9UTuh+AtaQD133A ORhYIatbAVLzF2KgZlmLZyX0reY17RL0Mpci9wsVNLJ8lAfLQCCkDXcWzmot7c8DTr3S SU5g== X-Gm-Message-State: AOAM530gf6mNFqdRraT+6jiSKtdYJLFW0D3Wo/szoUrCiqTr7EaNhtEG TOb96ueQvqPfNV4nER3DAs4Zn1DMKLtI0cchDXSGIg== X-Google-Smtp-Source: ABdhPJxLFe0ifBzSQIBXioyPixIsF51tIx7RKGeEqpYwiC2QLvRLZlCjMTzoqzh4c2B6Q8LmDm2C5NX/wjFcIV7kVNY= X-Received: by 2002:a25:810c:: with SMTP id o12mr14569991ybk.250.1630187277699; Sat, 28 Aug 2021 14:47:57 -0700 (PDT) MIME-Version: 1.0 References: <20210827191858.2037087-1-surenb@google.com> <20210827191858.2037087-3-surenb@google.com> <202108272228.7D36F0373@keescook> In-Reply-To: <202108272228.7D36F0373@keescook> From: Suren Baghdasaryan Date: Sat, 28 Aug 2021 14:47:46 -0700 Message-ID: Subject: Re: [PATCH v8 2/3] mm: add a field to store names for private anonymous memory To: Kees Cook Cc: Matthew Wilcox , Andrew Morton , Colin Cross , Sumit Semwal , Michal Hocko , Dave Hansen , "Kirill A . Shutemov" , Vlastimil Babka , Johannes Weiner , Jonathan Corbet , Al Viro , Randy Dunlap , Kalesh Singh , Peter Xu , rppt@kernel.org, Peter Zijlstra , Catalin Marinas , vincenzo.frascino@arm.com, =?UTF-8?B?Q2hpbndlbiBDaGFuZyAo5by16Yym5paHKQ==?= , Axel Rasmussen , Andrea Arcangeli , Jann Horn , apopple@nvidia.com, John Hubbard , Yu Zhao , Will Deacon , fenghua.yu@intel.com, thunder.leizhen@huawei.com, Hugh Dickins , feng.tang@intel.com, Jason Gunthorpe , Roman Gushchin , Thomas Gleixner , krisman@collabora.com, chris.hyser@oracle.com, Peter Collingbourne , "Eric W. Biederman" , Jens Axboe , legion@kernel.org, eb@emlix.com, Muchun Song , Viresh Kumar , thomascedeno@google.com, sashal@kernel.org, cxfcosmos@gmail.com, linux@rasmusvillemoes.dk, LKML , linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm , kernel-team Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=MzSuWBFZ; spf=pass (imf13.hostedemail.com: domain of surenb@google.com designates 209.85.219.182 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 88E95101EA63 X-Stat-Signature: 6c5d9mo3be45i894cag1cfbhh3g7mqn7 X-HE-Tag: 1630187278-50343 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Aug 27, 2021 at 10:52 PM Kees Cook wrote: > > On Sat, Aug 28, 2021 at 02:47:03AM +0100, Matthew Wilcox wrote: > > On Fri, Aug 27, 2021 at 12:18:57PM -0700, Suren Baghdasaryan wrote: > > > + anon_name = vma_anon_name(vma); > > > + if (anon_name) { > > > + seq_pad(m, ' '); > > > + seq_puts(m, "[anon:"); > > > + seq_write(m, anon_name, strlen(anon_name)); > > > + seq_putc(m, ']'); > > > + } > > Maybe after seq_pad, use: seq_printf(m, "[anon:%s]", anon_name); Good idea. Will change. > > > > > ... > > > > > + case PR_SET_VMA_ANON_NAME: > > > + name = strndup_user((const char __user *)arg, > > > + ANON_VMA_NAME_MAX_LEN); > > > + > > > + if (IS_ERR(name)) > > > + return PTR_ERR(name); > > > + > > > + for (pch = name; *pch != '\0'; pch++) { > > > + if (!isprint(*pch)) { > > > + kfree(name); > > > + return -EINVAL; > > > > I think isprint() is too weak a check. For example, I would suggest > > forbidding the following characters: ':', ']', '[', ' '. Perhaps > > isalnum() would be better? (permit a-zA-Z0-9) I wouldn't necessarily > > be opposed to some punctuation characters, but let's avoid creating > > confusion. Do you happen to know which characters are actually in use > > today? > > There's some sense in refusing [, ], and :, but removing " " seems > unhelpful for reasonable descriptors. As long as weird stuff is escaped, > I think it's fine. Any parser can just extract with m|\[anon:(.*)\]$| I see no issue in forbidding '[' and ']' but whitespace and ':' are currently used by Android. Would forbidding or escaping '[' and ']' be enough? > > For example, just escape it here instead of refusing to take it. Something > like: > > name = strndup_user((const char __user *)arg, > ANON_VMA_NAME_MAX_LEN); > escaped = kasprintf(GFP_KERNEL, "%pE", name); Did you mean "%*pE" as in https://www.kernel.org/doc/html/latest/core-api/printk-formats.html#raw-buffer-as-an-escaped-string ? > if (escaped) { > kfree(name); > return -ENOMEM; > } > kfree(name); > name = escaped; > > -- > Kees Cook