From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2F0B4606A323 for ; Fri, 13 Nov 2026 21:37:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=l8iDfR4F Received: by kanga.kvack.org (Postfix) id 5BB186B05E2; Fri, 13 Nov 2026 16:37:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 56AD36B05E3; Fri, 13 Nov 2026 16:37:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4337B6B05E4; Fri, 13 Nov 2026 16:37:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 172816B05E2 for ; Fri, 13 Nov 2026 16:37:52 -0500 (EST) Received: from smtpin24.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id A3CE31C2C88 for ; Fri, 13 Nov 2026 21:37:51 +0000 (UTC) X-FDA: 85431408342.24.A200C50 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf11.hostedemail.com (Postfix) with ESMTP id E30704000C for ; Fri, 13 Nov 2026 21:37:49 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=l8iDfR4F; spf=pass (imf11.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1794605870; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=PLiqukr56C60XaYU/sHWlWdxScdz3EOuf+dLUbwdnhA=; b=Kefl0VAFD9mLu/+vKa51RYC4cBYBvFeL1fDeAQHVvcxlAQz/7mFxcmF+EnwoK7RGK968iF 1mzwpS55Fhs+/9aXOkPo1/tAuAetTzofjvOLsY4qEVVKvNxE7qFE8gQUpMxjTwWTfHqJUN lp5Sgkp8+7UDZatybvGW0u2iFCCYFUw= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1794605870; b=zKaI+G9MFkxKMJITmVQp0TWCJ9uiA7hx6QjIz8wnSRIKIo2hwaXDiXEYbeIzYpi2RJ6cH1 Z0oChZPdrkw2Y9BsjGZDi/YvTRE2sBaw8ob/6rPeIF6B05r+oTVpeL/eLQaio8PZselT4z uEn27o+MRdQ6ktL0f7I6jastVaI9W4k= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=l8iDfR4F; spf=pass (imf11.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 7FFF063201; Fri, 13 Nov 2026 21:37:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A744E1F000C8; Fri, 13 Nov 2026 21:37:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794605869; bh=PLiqukr56C60XaYU/sHWlWdxScdz3EOuf+dLUbwdnhA=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=l8iDfR4Fn+bZOr3+4kgWweW+qnLrj4VKaTg7QNEbpGu/bEFZFs5nxDoj/kJFmkOuy EswQFyeO0xhnKCfhg9Fxv8R+Ji1avzOxEhknOfUoFWfFiXvnBRtnwyyyT1s1E5sLGu rIPhwMSSDY/K7NBkMePLqfgNHfXEju4yXrJZUlkEDDfvGmMgZ+2xSUi5eCDJEAeMnq WMzbhlrefYk1jGACsD+PV+Ez4GFWp47Mw/5VoaKhHD++z7JVYv/6kJRB9nIiu2zwJO GmY07jFS33ITqgEDCXs0F5jYryk6WirTuUlUhlluTjjhZp/zdu9BtuPbQv8qObwJJe 2RxDNmut2VdaQ== Message-ID: Date: Fri, 13 Nov 2026 22:37:14 +0100 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 5/5] mm: check permissions and bounds for vm_ops->access To: "Kuehling, Felix" , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Andrew Morton , Willy Tarreau , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Simona Vetter , Chris Wilson , Matthew Auld , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , "Ritesh Harjani (IBM)" , Shrikanth Hegde , Rik van Riel , Benjamin Herrenschmidt Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linuxppc-dev@lists.ozlabs.org, stable@vger.kernel.org, =?UTF-8?Q?Christian_K=C3=B6nig?= , Chris Mason References: <20261112-access_shite-v1-0-988a5c470db2@kernel.org> <20261112-access_shite-v1-5-988a5c470db2@kernel.org> <4b9042de-973a-4036-a6a0-2294c65a1ee1@amd.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <4b9042de-973a-4036-a6a0-2294c65a1ee1@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-12.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam09 X-Stat-Signature: ecu9dgquixwmcjkn3p93ecpnwn5ws91w X-Rspamd-Queue-Id: E30704000C X-Rspam-User: X-HE-Tag: 1794605869-733694 X-HE-Meta: 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 txiD87KU Qo/wxg+qqrC8Zp0Yq9wkxwryjhJrpErlmpz+aXseYSNAYgm8k8lMSqbZVrJMUCZmm9mhSLKvMJjw2D+vzaBlneezgbfVyWYDxH921zt4s2Jq7b6Ug6W8R4Qu9XmXVDoUNZyTxXZJR1M6/wP9Wd66q0XtU2OXbtG/ixoDdzOJXjVeOncDnIvDq2wz9OuTvreCOk2s7z0NZ6bsVjCiBHobv9uLC4tGCtLrWyOHHeGEFbY3Gc3KIQHsSaZKkwh11NWkOBVyDa46IGvAUT/5uiRYOnTmlZNnKgL1t+IQtCCKK41kN9OP3nK2vSu2p+S5gkJmxAOdTH/LyanCNAX5yXvhLNCRWvm45ATGPMjfqgIV62SAjpzvwP59Mf9TWt6t7Y8PoAM8FxvcDjOdtjhTravwoTd2idQnwMXzTX4fsKdasFTKmKuk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 11/13/26 21:25, Kuehling, Felix wrote: > > On 2026-11-12 17:09, David Hildenbrand (Arm) wrote: >> GUP rejects VM_IO and VM_PFNMAP mappings early. __access_remote_vm() then >> falls back to vm_ops->access without checking VMA permissions and without >> limiting the request to the VMA size. >> >> Consequently, /proc//mem can bypass protections even without >> FOLL_FORCE, or cross into another mapping without checking its >> permissions. >> >> Check VMA permissions before calling ->access and limit each request to >> the current VMA. Implement similar access permission checks as GUP, >> however: >>   (1) Reject writes to CoW mappings because the callbacks access backing >>       memory directly and cannot handle CoW. >>   (2) Allow forced writes to non-CoW mappings with VM_MAYWRITE. >> >> This intentionally breaks forced writes through legacy amdgpu PROT_NONE, >> MAP_PRIVATE debugger mappings. The workaround in commit fa5239f2af98 >> ("drm/amdgpu: workaround failed COW checks for Thunk VMAs") cleared >> VM_MAYWRITE to avoid CoW, but debugger writes still succeeded by >> exploiting the missing access-permission checks fixed here. Reads remain >> supported. Userspace must use MAP_SHARED instead; ROCm 5.5.0, released >> in May 2023, already does so. > > Thank you for considering this use case and checking the ROCm history. The patch is > > Acked-by: Felix Kuehling Thanks a lot for the confirmation, appreciated! -- Cheers, David