From patchwork Thu Feb 16 09:16:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muhammad Usama Anjum X-Patchwork-Id: 57935 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:eb09:0:0:0:0:0 with SMTP id s9csp199050wrn; Thu, 16 Feb 2023 01:27:22 -0800 (PST) X-Google-Smtp-Source: AK7set8Q2++e5Pj/Pyz/CqL8NieLIsbMfGvOv0/OMZXBUe7Q0RGSzRi6t+JMS1QzOqIL/rZtDywp X-Received: by 2002:a05:6402:3813:b0:4ad:23f:90a7 with SMTP id es19-20020a056402381300b004ad023f90a7mr1413271edb.13.1676539642299; Thu, 16 Feb 2023 01:27:22 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1676539642; cv=none; d=google.com; s=arc-20160816; b=GhBYp57fn83ZvmFSwJYx+gbq55Fhr/lMDMOHaooJr0ESerAMlAkHwuILTGrCpVaxi8 8100VgI6pZR59Hg0qRRjcn4YHqTnRAazwINwpJ7LKdhhIgsVWk0q3eTaoJZpA4licven oltz7uKwujF8TpR+ef9eQ90TgAk06hKZnNhhi8IT4bv/isqVnWxIdA6ljU6PRwUSzFrv KrvO4+N2yCNjX59GNTacb4lV2bBF1jUhAZyQ7YrWxlgU2Vq56dl4fsFp+hY+0mrnDp7B DP4iAnwXtFBEmBBK9ri48LbxUOUXjXMXt/mZxXg9WrrLPY3c9qX9WPBfqkAiNlf7u61x ColQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :message-id:date:subject:cc:to:from:dkim-signature; bh=0MJ6ecVV64FgFs2msM3AZ9E5VG7YSbLwrGiSZoIt9HQ=; b=eWHjgnGNqnDkn9EBrgZKznimsI6HSTXnfxZWkGcy/M4d9PCNHHxIPlvty3Gre5DaZh rTBw3NlVfMsiDKsMLJpXh420bMFdqSupK8yaZrRUfRfs68Zv9ZhWvwqx3XjYtwiAMzCS FN7xcesDLS2atdRedfYMtjVIVTdQrtcJguOBYFOvZqzqkCuE0Cg0M6kFxs/fomgN5hY1 dcZ5PXNPr3ndE07sqgYqjUMbvrBeXq80Wsm8wNy2yQGwSVzr21F4GbpH0QAjG0bQLxo1 o5bdivH1711Hg/OkqqEVX4Mg8SJ51f8Ms60lYX3BsGOsYi0HpM8Mgh7lNQEV/wlxJ5Fv p0Zw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@collabora.com header.s=mail header.b=XU1WgQCR; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=collabora.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id p2-20020a056402074200b004ace49cbc82si1584936edy.621.2023.02.16.01.26.59; Thu, 16 Feb 2023 01:27:22 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@collabora.com header.s=mail header.b=XU1WgQCR; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=collabora.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229768AbjBPJRY (ORCPT + 99 others); Thu, 16 Feb 2023 04:17:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229625AbjBPJRV (ORCPT ); Thu, 16 Feb 2023 04:17:21 -0500 Received: from madras.collabora.co.uk (madras.collabora.co.uk [46.235.227.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C36911C7E7 for ; Thu, 16 Feb 2023 01:17:18 -0800 (PST) Received: from localhost.localdomain (unknown [39.45.217.110]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: usama.anjum) by madras.collabora.co.uk (Postfix) with ESMTPSA id DD7F1660219B; Thu, 16 Feb 2023 09:17:14 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1676539037; bh=p4O0JNqalB3DAfjfajI/CREv4U82nvTHiokxTLoKpk8=; h=From:To:Cc:Subject:Date:From; b=XU1WgQCRSsJY1e29r6FI2zJEyv/jAz6OCElh7uJFm7MQQsehZiLzQxp4UOkuiD890 t0/pMZ7ivUSue7NYar66RJl2AkCmiY1rfDSLlRR2WHg+lZRipo9nfTsQY6bjMZqDGM h92lTZ6S/8Cyk9YRp0P4d1HL0Jr50gxW6KRtYmIrtTCzJgnh6BbsuN7FqF4cb9m9kE bdV2t1q+2TErvBlTpjw72dJy2pHXHJkOS74depQNWhQtvjQIguNxgmsoYLSjy5+7jP r7WqQZbiKXbLrLnyRodnotGJCmUA68KBF348rmo5u8rktY+0/LYzVEzsCzSgzOJsug ajRGcznHfbDHg== From: Muhammad Usama Anjum To: peterx@redhat.com, david@redhat.com, Andrew Morton Cc: Muhammad Usama Anjum , kernel@collabora.com, Paul Gofman , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 1/2] mm/userfaultfd: Support WP on multiple VMAs Date: Thu, 16 Feb 2023 14:16:55 +0500 Message-Id: <20230216091656.2045471-1-usama.anjum@collabora.com> X-Mailer: git-send-email 2.39.1 MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1757735339494299958?= X-GMAIL-MSGID: =?utf-8?q?1757979231629108211?= mwriteprotect_range() errors out if [start, end) doesn't fall in one VMA. We are facing a use case where multiple VMAs are present in one range of interest. For example, the following pseudocode reproduces the error which we are trying to fix: - Allocate memory of size 16 pages with PROT_NONE with mmap - Register userfaultfd - Change protection of the first half (1 to 8 pages) of memory to PROT_READ | PROT_WRITE. This breaks the memory area in two VMAs. - Now UFFDIO_WRITEPROTECT_MODE_WP on the whole memory of 16 pages errors out. This is a simple use case where user may or may not know if the memory area has been divided into multiple VMAs. We need an implementation which doesn't disrupt the already present users. So keeping things simple, stop going over all the VMAs if any one of the VMA hasn't been registered in WP mode. While at it, remove the un-needed error check as well. Reported-by: Paul Gofman Signed-off-by: Muhammad Usama Anjum Acked-by: David Hildenbrand Acked-by: Peter Xu --- Changes since v3: - Rebase on top of next-20230616 Changes since v2: - Correct the return error code and cleanup a bit Changes since v1: - Correct the start and ending values passed to uffd_wp_range() --- mm/userfaultfd.c | 39 ++++++++++++++++++++++----------------- 1 file changed, 22 insertions(+), 17 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 53c3d916ff66..77c5839e591c 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -741,9 +741,12 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start, unsigned long len, bool enable_wp, atomic_t *mmap_changing) { + unsigned long end = start + len; + unsigned long _start, _end; struct vm_area_struct *dst_vma; unsigned long page_mask; long err; + VMA_ITERATOR(vmi, dst_mm, start); /* * Sanitize the command parameters: @@ -766,28 +769,30 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start, goto out_unlock; err = -ENOENT; - dst_vma = find_dst_vma(dst_mm, start, len); + for_each_vma_range(vmi, dst_vma, end) { - if (!dst_vma) - goto out_unlock; - if (!userfaultfd_wp(dst_vma)) - goto out_unlock; - if (!vma_can_userfault(dst_vma, dst_vma->vm_flags)) - goto out_unlock; + if (!userfaultfd_wp(dst_vma)) { + err = -ENOENT; + break; + } - if (is_vm_hugetlb_page(dst_vma)) { - err = -EINVAL; - page_mask = vma_kernel_pagesize(dst_vma) - 1; - if ((start & page_mask) || (len & page_mask)) - goto out_unlock; - } + if (is_vm_hugetlb_page(dst_vma)) { + err = -EINVAL; + page_mask = vma_kernel_pagesize(dst_vma) - 1; + if ((start & page_mask) || (len & page_mask)) + break; + } - err = uffd_wp_range(dst_mm, dst_vma, start, len, enable_wp); + _start = max(dst_vma->vm_start, start); + _end = min(dst_vma->vm_end, end); - /* Return 0 on success, <0 on failures */ - if (err > 0) - err = 0; + err = uffd_wp_range(dst_mm, dst_vma, _start, _end - _start, enable_wp); + /* Return 0 on success, <0 on failures */ + if (err < 0) + break; + err = 0; + } out_unlock: mmap_read_unlock(dst_mm); return err; From patchwork Thu Feb 16 09:16:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muhammad Usama Anjum X-Patchwork-Id: 57936 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:eb09:0:0:0:0:0 with SMTP id s9csp199309wrn; Thu, 16 Feb 2023 01:28:17 -0800 (PST) X-Google-Smtp-Source: AK7set+MspBmiOGPHY42vdKTd2+7vqDxIzpsYq4aD3Qum9hR+KKEdlJktVOD0EU0WURBk93v+0uH X-Received: by 2002:a17:907:2ce4:b0:877:a3c4:807b with SMTP id hz4-20020a1709072ce400b00877a3c4807bmr7702519ejc.68.1676539697807; Thu, 16 Feb 2023 01:28:17 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1676539697; cv=none; d=google.com; s=arc-20160816; b=cKIG0AGxQ1hcUttq5dfoVrk65uz5G4zWWc6RmwmGK5ZVWy8/GYq4ATgjmXZSzEXsNG 17u8e5a7hykcPtihemY7LKhV/TAEu10H9YQAuUU/PToHuHkG1piYKTfzTgO77calOJ+3 V1jRqVoReoihOOG9xu018u5a6On4g8VO1Diiv+s/VaWrgvh6JD4jR90llrfVNWnGEit5 THYc97fSKwOlsfL+DFBc+4uLtfZ7oBM3PlQ6tDrxJN/v7NuJESLpbxcvxoA6Lr+WtTnw 3OqmaE2irm7v9jWBwXgCvY9TLkO5snE2oO83TIGx41/wMN5FddLjoVp1U0mniqx8e7cX dMxQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=K3lFMhak3aYOcGIprm04ZPQEkc3xI1jgYekJJdax6BQ=; b=Bff+PtK8UyxczYs+Qpm5MO4GvCiq880KS5WYLnVCPvPBvcpYBD0WZFqdwCo16vKZ8Z wpC+ElGjwvKQjlSrEjcKp0OfRdT3umoYOa35VvH91oqa64twdb4gbA8zfngUmRIAS7/o sGAVJD4LyLpJb3/ip4aHxp7NRP5Bv9a7iHmDODeUjM6C/DzKi7mYJZG1Uy7cGgWq+aki lf8XeYZZEazFqwBxBzNRuDtXslojy7/N5oMR9WTNCgITJLxPmW+vjMh303wgD/bSDSOp 95FKeBcrE3SZSi/5AeDwAuOpNMJkuBR3hfar5yZRqhKwTUT/dad54Nw9NBJhoeeE84U3 PwpQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@collabora.com header.s=mail header.b=hXppeNF6; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=collabora.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id cm7-20020a170907938700b008b14042fa1bsi1418702ejc.255.2023.02.16.01.27.54; Thu, 16 Feb 2023 01:28:17 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@collabora.com header.s=mail header.b=hXppeNF6; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=collabora.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229882AbjBPJSI (ORCPT + 99 others); Thu, 16 Feb 2023 04:18:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32854 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229800AbjBPJSD (ORCPT ); Thu, 16 Feb 2023 04:18:03 -0500 Received: from madras.collabora.co.uk (madras.collabora.co.uk [46.235.227.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A59F82068A for ; Thu, 16 Feb 2023 01:18:01 -0800 (PST) Received: from localhost.localdomain (unknown [39.45.217.110]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: usama.anjum) by madras.collabora.co.uk (Postfix) with ESMTPSA id B6820660219B; Thu, 16 Feb 2023 09:17:58 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1676539080; bh=eN35qv1LQnqiL94LOpdwsRPxsfQxNRRB3+34BVt+3/g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hXppeNF6RgBlcVGgaFAGBHmpAy9Zonunn8zH1SUsH0SbgvHwyDQ6xVh8Q/nxGdKFs 495IqxX+srlyIzYUvEvCyQortt7XmNpJJD/9gIdbyZ9xQi17ioi30ymeUajEeWYC83 4NxxHC/EeJnyJ4XK54d7AW+2IbrnTU/NcELTXRrHUQhgFQDztv+lMzZJTkp6yUQXhI vhoIewxGXKTkkD1izP+GxMFpAbSmMDPfm3RIoIdfZEQDsAFclK60r940C6p4XqQx8T cVTO2CKICrClksWOIx5b2asP1noUwXIORO3Y9rYczrtt8n9apz+wXM8QatF6yS+gI3 AIGihfHZqYJfg== From: Muhammad Usama Anjum To: peterx@redhat.com, david@redhat.com, Andrew Morton Cc: Muhammad Usama Anjum , kernel@collabora.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 2/2] mm/userfaultfd: add VM_WARN_ONCE() Date: Thu, 16 Feb 2023 14:16:56 +0500 Message-Id: <20230216091656.2045471-2-usama.anjum@collabora.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230216091656.2045471-1-usama.anjum@collabora.com> References: <20230216091656.2045471-1-usama.anjum@collabora.com> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1757979290465422269?= X-GMAIL-MSGID: =?utf-8?q?1757979290465422269?= Add VM_WARN_ONCE() to uffd_wp_range() to detect range (start, len) abuse. Signed-off-by: Muhammad Usama Anjum --- mm/userfaultfd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 77c5839e591c..d89ed44d2668 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -717,6 +717,8 @@ long uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *dst_vma, struct mmu_gather tlb; long ret; + VM_WARN_ONCE(start < dst_vma->vm_start || start + len > dst_vma->vm_end, + "The address range exceeds VMA boundary.\n"); if (enable_wp) mm_cp_flags = MM_CP_UFFD_WP; else