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=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 E103DC433FE for ; Fri, 3 Sep 2021 21:47:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6097561057 for ; Fri, 3 Sep 2021 21:47:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 6097561057 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 8E76F6B0071; Fri, 3 Sep 2021 17:47:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 896FE900002; Fri, 3 Sep 2021 17:47:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 75DFA6B0073; Fri, 3 Sep 2021 17:47:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0114.hostedemail.com [216.40.44.114]) by kanga.kvack.org (Postfix) with ESMTP id 64BF36B0071 for ; Fri, 3 Sep 2021 17:47:05 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id E8D91184EACF3 for ; Fri, 3 Sep 2021 21:47:04 +0000 (UTC) X-FDA: 78547597968.06.E278785 Received: from mail-pg1-f176.google.com (mail-pg1-f176.google.com [209.85.215.176]) by imf09.hostedemail.com (Postfix) with ESMTP id 954563000100 for ; Fri, 3 Sep 2021 21:47:04 +0000 (UTC) Received: by mail-pg1-f176.google.com with SMTP id w8so370418pgf.5 for ; Fri, 03 Sep 2021 14:47:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=R1bYmjTKExX6JhEiFOJnD/oqcz6UJ6jC0pHYWsTKBDs=; b=OfbJLxMQu6pj30fFIOlmMUIGQCvb6KKk+9r2hRYvK14B0p9yAa4u4lckrNox3opWlv e+CnUR4dvZ5OkgpAbUqMh+PBobSMior4wj6wcNd4ot99aaW3T7fu0L6jDnAlM+s2/k8v O8l6zG7Gq5rTedFzfLdpshq7BjPr6Zahzhxew= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=R1bYmjTKExX6JhEiFOJnD/oqcz6UJ6jC0pHYWsTKBDs=; b=eX1Dg4LzfYnYcyYk9Z55YpxCYzSMPUJPYF8Y/BHaQlTRZrBe0yZDo7WvUzYId6FyHT gXXZCDeQKf93RMW4GgCAS/h6Vahs15ftwadofgY8PYXBsJHNU5SECymopgNGtpOeL9U2 FND4rXsQWC6F17HqRYELBODeWgGlb3/op4MB5wX7xQllZTTW8WwtuZbmnWS7bDytu+di e4y3vgoW/2IaORSSuJGkzH9AA59zCUjdNslMUVVHkwOhxLSNau4KHY0qJ9oMX9y5sT5d lZfypadxxqGnnvw540ryW3XsBsxGMTfA29j2Q51e+01OgQzGghTe6SlH0SyUuqJGLM2q y1QA== X-Gm-Message-State: AOAM5336dlrCSEc6ecMEENzYrK/0ArinzbKaVjx8z5WDWpJ/Ekx8WAIK UwUNSEnXJ1t+QT8w0kAsooML6sp6YyhcIA== X-Google-Smtp-Source: ABdhPJz+Ei3gb17X1dhyb0eeklFvEiEXy52fab+dYlg6aQf2iyHFV7bY1p9iHQxqzKWYOqV5wJ9yLQ== X-Received: by 2002:a62:1d10:0:b0:408:9989:3c88 with SMTP id d16-20020a621d10000000b0040899893c88mr845229pfd.22.1630705623613; Fri, 03 Sep 2021 14:47:03 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id m28sm335674pgl.9.2021.09.03.14.47.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Sep 2021 14:47:02 -0700 (PDT) Date: Fri, 3 Sep 2021 14:47:01 -0700 From: Kees Cook To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, ccross@google.com, sumit.semwal@linaro.org, mhocko@suse.com, dave.hansen@intel.com, willy@infradead.org, kirill.shutemov@linux.intel.com, vbabka@suse.cz, hannes@cmpxchg.org, corbet@lwn.net, viro@zeniv.linux.org.uk, rdunlap@infradead.org, kaleshsingh@google.com, peterx@redhat.com, rppt@kernel.org, peterz@infradead.org, catalin.marinas@arm.com, vincenzo.frascino@arm.com, chinwen.chang@mediatek.com, axelrasmussen@google.com, aarcange@redhat.com, jannh@google.com, apopple@nvidia.com, jhubbard@nvidia.com, yuzhao@google.com, will@kernel.org, fenghua.yu@intel.com, thunder.leizhen@huawei.com, hughd@google.com, feng.tang@intel.com, jgg@ziepe.ca, guro@fb.com, tglx@linutronix.de, krisman@collabora.com, chris.hyser@oracle.com, pcc@google.com, ebiederm@xmission.com, axboe@kernel.dk, legion@kernel.org, eb@emlix.com, gorcunov@gmail.com, songmuchun@bytedance.com, viresh.kumar@linaro.org, thomascedeno@google.com, sashal@kernel.org, cxfcosmos@gmail.com, linux@rasmusvillemoes.dk, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, kernel-team@android.com Subject: Re: [PATCH v9 2/3] mm: add a field to store names for private anonymous memory Message-ID: <202109031439.B58932AF0@keescook> References: <20210902231813.3597709-1-surenb@google.com> <20210902231813.3597709-2-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210902231813.3597709-2-surenb@google.com> Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=OfbJLxMQ; dmarc=pass (policy=none) header.from=chromium.org; spf=pass (imf09.hostedemail.com: domain of keescook@chromium.org designates 209.85.215.176 as permitted sender) smtp.mailfrom=keescook@chromium.org X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 954563000100 X-Stat-Signature: dqi8tq767w4iae548wyzobhu73dgcjan X-HE-Tag: 1630705624-82003 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000005, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: (Sorry, a few more things jumped out at me when I looked again...) On Thu, Sep 02, 2021 at 04:18:12PM -0700, Suren Baghdasaryan wrote: > [...] > diff --git a/kernel/sys.c b/kernel/sys.c > index 72c7639e3c98..25118902a376 100644 > --- a/kernel/sys.c > +++ b/kernel/sys.c > @@ -2299,6 +2299,64 @@ int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which, > > #define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE) > > +#ifdef CONFIG_MMU > + > +#define ANON_VMA_NAME_MAX_LEN 256 > + > +static inline bool is_valid_name_char(char ch) > +{ > + /* printable ascii characters, except [ \ ] */ > + return (ch > 0x1f && ch < 0x5b) || (ch > 0x5d && ch < 0x7f); > +} In the back of my mind, I feel like disallowing backtick would be nice, but then if $, (, and ) are allowed, it doesn't matter, and that seems too limiting. :) > + > +static int prctl_set_vma(unsigned long opt, unsigned long addr, > + unsigned long size, unsigned long arg) > +{ > + struct mm_struct *mm = current->mm; > + const char __user *uname; > + char *name, *pch; > + int error; > + > + switch (opt) { > + case PR_SET_VMA_ANON_NAME: > + uname = (const char __user *)arg; > + if (!uname) { > + /* Reset the name */ > + name = NULL; > + goto set_name; > + } > + > + name = strndup_user(uname, ANON_VMA_NAME_MAX_LEN); > + > + if (IS_ERR(name)) > + return PTR_ERR(name); > + > + for (pch = name; *pch != '\0'; pch++) { > + if (!is_valid_name_char(*pch)) { > + kfree(name); > + return -EINVAL; > + } > + } > +set_name: > + mmap_write_lock(mm); > + error = madvise_set_anon_name(mm, addr, size, name); > + mmap_write_unlock(mm); > + kfree(name); > + break; This is a weird construct with a needless goto. Why not: switch (opt) { case PR_SET_VMA_ANON_NAME: uname = (const char __user *)arg; if (uname) { name = strndup_user(uname, ANON_VMA_NAME_MAX_LEN); if (IS_ERR(name)) return PTR_ERR(name); for (pch = name; *pch != '\0'; pch++) { if (!is_valid_name_char(*pch)) { kfree(name); return -EINVAL; } } } else { /* Reset the name */ name = NULL; } mmap_write_lock(mm); error = madvise_set_anon_name(mm, addr, size, name); mmap_write_unlock(mm); kfree(name); break; -- Kees Cook