From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F199029993A for ; Mon, 6 Oct 2025 13:53:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759758836; cv=none; b=ddhdpGlyOe9S7IAHzUydscCZ5cfwXINn9ntEv4QgIPd+lIp03O/pbRucefkfbXgWPbjDpb29/wuOAaj3F0SaEsA0rasVqLPGFx3Hf1gT8AjlwrzlD9wUhdfavqaUJAJIaLvxVPPSCRVrWXd4VW0jYRyq6QXmrvuohy0UwVCqcbw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759758836; c=relaxed/simple; bh=NzuZ2WimXZhzKfuoxT422QsjdAD7EiCbAZGkcz1OTCM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OKU4HNj+mAF5NRrsTxf00aPOYDjXPKoKSv2SX/qfy0XZLrdkJLwHkDv2oaVJl1eCj2cirsmDNCqGzjx53YLxYKLTcJzIPcS06xWHts997jCQ7KLtzyFd4K8/ykMrNqbng6r1y0kI4EN7/IsA9UXChCX5+hVU+SFZY3pWe88KDq8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=UPWq1XuA; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UPWq1XuA" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1759758834; h=from:from: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:autocrypt:autocrypt; bh=CGLl7ctOpTpoDpfWPZR3DaFESuMtpId6EeCDbxcp3bo=; b=UPWq1XuA/49ukencketvt4Eu+JfBi16KKoXODqFznozKYnGSxzvXDEqxzOGHLTc40rDKpi 0xvI4FwIpHH+ca7vd8DiBRVzfiuQ0obGJcjRM8uTtTrDi8/SIy2UqcJnQdKq7mTdknrgE/ OOyBgRP3SooLWpmmkXb1SaojcIZNTHg= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-191-_RKh65AZPFKAD_EDPl0hKA-1; Mon, 06 Oct 2025 09:53:50 -0400 X-MC-Unique: _RKh65AZPFKAD_EDPl0hKA-1 X-Mimecast-MFC-AGG-ID: _RKh65AZPFKAD_EDPl0hKA_1759758830 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-41066f050a4so1824693f8f.1 for ; Mon, 06 Oct 2025 06:53:50 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759758829; x=1760363629; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=CGLl7ctOpTpoDpfWPZR3DaFESuMtpId6EeCDbxcp3bo=; b=VGG21VCD/1f24GNyTP/vMfZj/9v6o2QAxJWkY81vtXZGgmdvzjscr2innasrmdJ1QK tequh3hZogUCMfzGNgC/Lvc2M9m0Y7K/43twkA5kEtMAWDVEi2HNPj+UzdgHTMDGvaUw 4nQZVPvQ4VkX/vtRzAHBWh7brXpT8HssygLh2VeMs2YbAHie89Pjiz4or0PrvRvZzh0y W1YUUXFTVSI2ZdLsbpGvA36JaA1S3dPBJDSLnkotVcMVUC8FJAlOUtELwFoD0iWlijmV spQkULx7M5ufipuXipY1u1za9h3K/a1jUwU33xWXKS+0BlOSF2UjJ6XtThjArpp1ebkx wUKw== X-Forwarded-Encrypted: i=1; AJvYcCVgIAyy7y/D7Eqrhfo8ctXjXzMzSxozsKAMmF9gxEWl0ssbz8TUWn0LD2/B3X2qZtwSWHMT8X+vdrw3icQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yxi6k97h5+GbS27KYkET2mIDecXHqu5AvW9XQdWFGofTutzRZgC iPuZA2mYAUzPP1CxH+t/EYGj7a/EuocfJAGC4kyynon20TFA+zS1pdlTlGZQYfIjJOaeRugv3nY +s1aPlyBbeAU0pgv5RqjMDujGH3XI+BVLvGZKKhHj3dcNDiUuvs6YJq6O0jfhuG8+RQ== X-Gm-Gg: ASbGncuufU1PRKwbkeDZ0Hoq7Gg7cn2h+hclb7D0XZD2FXiRgXGkpPhlRXebL77/c48 dnI4MAKTxUrjatHdx924UAXEP0jkKf0JIUgLmXtUIcZeDbKKj5KruPCZ2IdZADiuH0YTB4v8Qkx Ni/2b2nhbAP4wHJsZem0agiYrZlIULBXR8s1OmlaT9wWFxFHZQTQlB39zSmCHu3WALaqxzZPIRY 5D9uahB0HdE8qbYGHtiy6EsIoRIFm1evtyWKp3rGcULatQvX+T5Py9HvplfICQJNszllTv76C/r pyYrgLhd06d2/yXaVERgGrUgFwmApnwS4Z8fwBIWY4L3dGK+xdARdymuYaNR6tWVceVUnLKUljf ec46/czZp X-Received: by 2002:a5d:5885:0:b0:3cd:edee:c7f1 with SMTP id ffacd0b85a97d-425671aa965mr9519905f8f.56.1759758829621; Mon, 06 Oct 2025 06:53:49 -0700 (PDT) X-Google-Smtp-Source: AGHT+IG4z3VUwSp6NiPOhxjtLfmmF5LdjV37JJ4DT2V+xwJ/f0irliRMICXktxy6TvXFLIvLoD96wQ== X-Received: by 2002:a5d:5885:0:b0:3cd:edee:c7f1 with SMTP id ffacd0b85a97d-425671aa965mr9519876f8f.56.1759758829047; Mon, 06 Oct 2025 06:53:49 -0700 (PDT) Received: from [192.168.3.141] (tmo-083-110.customers.d1-online.com. [80.187.83.110]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4255d8e980dsm22658378f8f.36.2025.10.06.06.53.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Oct 2025 06:53:48 -0700 (PDT) Message-ID: <989c49fc-1f6f-4674-96e7-9f987ec490db@redhat.com> Date: Mon, 6 Oct 2025 15:53:46 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1] fsnotify: Pass correct offset to fsnotify_mmap_perm() To: Ryan Roberts , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Amir Goldstein Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20251003155238.2147410-1-ryan.roberts@arm.com> <66251c3e-4970-4cac-a1fc-46749d2a727a@arm.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+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: <66251c3e-4970-4cac-a1fc-46749d2a727a@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 06.10.25 14:14, Ryan Roberts wrote: > On 06/10/2025 12:36, David Hildenbrand wrote: >> On 03.10.25 17:52, Ryan Roberts wrote: >>> fsnotify_mmap_perm() requires a byte offset for the file about to be >>> mmap'ed. But it is called from vm_mmap_pgoff(), which has a page offset. >>> Previously the conversion was done incorrectly so let's fix it, being >>> careful not to overflow on 32-bit platforms. >>> >>> Discovered during code review. >>> >>> Cc: >>> Fixes: 066e053fe208 ("fsnotify: add pre-content hooks on mmap()") >>> Signed-off-by: Ryan Roberts >>> --- >>> Applies against today's mm-unstable (aa05a436eca8). >>> >> >> Curious: is there some easy way to write a reproducer? Did you look into that? > > I didn't; this was just a drive-by discovery. > > It looks like there are some fanotify tests in the filesystems selftests; I > guess they could be extended to add a regression test? > > But FWIW, I think the kernel is just passing the ofset/length info off to user > space and isn't acting on it itself. So there is no kernel vulnerability here. Right, I'm rather wondering if this could have been caught earlier and how we could have caught it earlier :) -- Cheers David / dhildenb