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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C31D4D21266 for ; Thu, 17 Oct 2024 09:18:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5FE6B6B0089; Thu, 17 Oct 2024 05:18:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 586E56B008A; Thu, 17 Oct 2024 05:18:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3D9986B008C; Thu, 17 Oct 2024 05:18:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 1CCCB6B0089 for ; Thu, 17 Oct 2024 05:18:42 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 782A81A1083 for ; Thu, 17 Oct 2024 09:18:22 +0000 (UTC) X-FDA: 82682543622.07.5B0CF4D Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf21.hostedemail.com (Postfix) with ESMTP id E547C1C0014 for ; Thu, 17 Oct 2024 09:18:20 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=RHQA2ouc; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf21.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1729156612; a=rsa-sha256; cv=none; b=6/Lt1YKlyBAgFHsxsXXwcjube5hgdqS50SjzIPj+TT/sY8xaTpTl0iT6A6gWX3aKBqWyZV pDFAScHuLGtavmtIRZVqMTusOmjVX+3hLy+H6T1opiS8Wi8Q49q9fQ1wKOqzEu8YRuu77i 91L4RJDPpgnKU8XYglQ6jix89EQtAg0= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=RHQA2ouc; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf21.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1729156612; 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=1cq4VAwbJYsp5619a/bS6cywsteQlYzK3685TSvl+Ec=; b=QsBYxfzcbzh/MQhFkNtHtWawAQS3Bp8Rx6VzrdJXY5q5aSRQbC28g2EV5MwqFdI+TQ91v3 eeW8muzp038z5fi5tXnPwe+v/C38I9+nx4UzpD3+hV68WHP4awtlxQFEPaPB08kaIQa9HR 7R9FgkPob4CyDLcfiYR5a5QaZKCDmfQ= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1729156718; 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=1cq4VAwbJYsp5619a/bS6cywsteQlYzK3685TSvl+Ec=; b=RHQA2oucrIn5LHctRQj3BqyZGtQI9WFsyam3ypT9bqDqJK7SXaZJMuWEmigD677dP+zwD5 fwWBg35fNfrLhP380Of824MlQArwLFUpWjOxDCYv169eOsnzRYQwLGwD3E7BGNStNSLxAd +ssV6OYnCgzJ2Kib8eT6HPwFsJJsXXo= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-593-J8ffyVvSNiqIZPHIo74gmw-1; Thu, 17 Oct 2024 05:18:37 -0400 X-MC-Unique: J8ffyVvSNiqIZPHIo74gmw-1 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-4315d98a873so1671505e9.1 for ; Thu, 17 Oct 2024 02:18:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729156716; x=1729761516; h=content-transfer-encoding:in-reply-to:organization: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=1cq4VAwbJYsp5619a/bS6cywsteQlYzK3685TSvl+Ec=; b=f5D09q4q/5E2/8s7SMy25ykGEIr+QfaotHVahOOgtD7IUxar8GvyVJfDGKG6Alml9S w8NCbXBBB2zB4s7eNMWiSHdW5ErkW7hCsRa5gohm0KQ29b1YRX9umbtsaMqx7MzwMvJv 5PibgxdYqrJyci3cteS2eC5zU1Q/kM0ZUNtnF8xmeRUDK2TIE7jQfysRVCaOOuhVmikk h3PTSsK79FGJ/QkJERpMIW8OEDgSHKB6DdYgR7Iz6kIZi5FZf2zIIvNsYkYE1+lshAZn ZP7aic/IoN/cwk1KqwgHVcCwG5T7UFfOXfNsD97sCsM2reM7nKjhjelZ3OrdNWMdKoAT 36yQ== X-Gm-Message-State: AOJu0YwimVPYRI1AZpkWJdYbQSF6p3fFNyqRg5vEiAnj5Z/r7q4yfs9b W+M90maoST9QGeO12Z5Gs3+fG595ilSMCIEWyF2MCKFkRSewOuF/+OvZHwxJUk9rlbsg7r2y/VZ QeqvsJu1EWLDFdRkqNQiu3baRK8Z3LHmcwWibbNZbnqkNDtcE X-Received: by 2002:a05:600c:1ca4:b0:42c:b63e:fe91 with SMTP id 5b1f17b1804b1-4311df42ce5mr207075085e9.24.1729156716275; Thu, 17 Oct 2024 02:18:36 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGyvskbYB3iLHdqhTBMWr6OcacaJ+LM+/c1icuN9n7aep9ir4TKAlvTHBqa3EZchJOUTDfyFw== X-Received: by 2002:a05:600c:1ca4:b0:42c:b63e:fe91 with SMTP id 5b1f17b1804b1-4311df42ce5mr207074835e9.24.1729156715832; Thu, 17 Oct 2024 02:18:35 -0700 (PDT) Received: from ?IPV6:2003:cb:c705:7600:62cc:24c1:9dbe:a2f5? (p200300cbc705760062cc24c19dbea2f5.dip0.t-ipconnect.de. [2003:cb:c705:7600:62cc:24c1:9dbe:a2f5]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43158c406a8sm19604475e9.28.2024.10.17.02.18.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 17 Oct 2024 02:18:35 -0700 (PDT) Message-ID: Date: Thu, 17 Oct 2024 11:18:34 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 bpf] lib/buildid: handle memfd_secret() files in build_id_parse() To: Andrii Nakryiko , bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, martin.lau@kernel.org Cc: linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, rppt@kernel.org, yosryahmed@google.com, shakeel.butt@linux.dev, Yi Lai References: <20241016221629.1043883-1-andrii@kernel.org> From: David Hildenbrand 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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20241016221629.1043883-1-andrii@kernel.org> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: E547C1C0014 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: sjfrhn61kpb9knt1xkqqkxgcetwwgtsq X-HE-Tag: 1729156700-639948 X-HE-Meta: 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 uz0r1LhS 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 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: List-Subscribe: List-Unsubscribe: On 17.10.24 00:16, Andrii Nakryiko wrote: > From memfd_secret(2) manpage: > > The memory areas backing the file created with memfd_secret(2) are > visible only to the processes that have access to the file descriptor. > The memory region is removed from the kernel page tables and only the > page tables of the processes holding the file descriptor map the > corresponding physical memory. (Thus, the pages in the region can't be > accessed by the kernel itself, so that, for example, pointers to the > region can't be passed to system calls.) > > So folios backed by such secretmem files are not mapped into kernel > address space and shouldn't be accessed, in general. > > To make this a bit more generic of a fix and prevent regression in the > future for similar special mappings, do a generic check of whether the > folio we got is mapped with kernel_page_present(), as suggested in [1]. > This will handle secretmem, and any future special cases that use > a similar approach. > > Original report and repro can be found in [0]. > > [0] https://lore.kernel.org/bpf/ZwyG8Uro%2FSyTXAni@ly-workstation/ > [1] https://lore.kernel.org/bpf/CAJD7tkbpEMx-eC4A-z8Jm1ikrY_KJVjWO+mhhz1_fni4x+COKw@mail.gmail.com/ > > Reported-by: Yi Lai > Suggested-by: Yosry Ahmed > Fixes: de3ec364c3c3 ("lib/buildid: add single folio-based file reader abstraction") > Signed-off-by: Andrii Nakryiko > --- > lib/buildid.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/lib/buildid.c b/lib/buildid.c > index 290641d92ac1..90df64fd64c1 100644 > --- a/lib/buildid.c > +++ b/lib/buildid.c > @@ -5,6 +5,7 @@ > #include > #include > #include > +#include > > #define BUILD_ID 3 > > @@ -74,7 +75,9 @@ static int freader_get_folio(struct freader *r, loff_t file_off) > filemap_invalidate_unlock_shared(r->file->f_mapping); > } > > - if (IS_ERR(r->folio) || !folio_test_uptodate(r->folio)) { > + if (IS_ERR(r->folio) || > + !kernel_page_present(&r->folio->page) || > + !folio_test_uptodate(r->folio)) { > if (!IS_ERR(r->folio)) > folio_put(r->folio); > r->folio = NULL; As replied elsewhere, can't we take a look at the mapping? We do the same thing in gup_fast_folio_allowed() where we check secretmem_mapping(). -- Cheers, David / dhildenb