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imf27.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=Hwhsj8kN; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf27.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793048909; b=cv7NnHMuqeC4jnPNNZoro37ke9YfREbk6pJbcDFtiDUs3R5jwRDUTz/QRqtLP1ep7hVUQk jMkkqxSRwk1gae2pxKArDhZNbeNNDlSv38n+d5Y4wO+sRgp//3HW+gwJ7sdTWqVttB1kDp 9U2WzgRxnCwJbKjXkutXxq7g6uWhCVA= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 3871F601EF; Mon, 26 Oct 2026 21:08:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B4DF1F01828; Mon, 26 Oct 2026 21:08:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793048908; bh=aZY6emueEsceME7nXNq6gUfKhqrQcT2cFezDIABkUGw=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=Hwhsj8kNM/003xoVUCIY6kkGhTMwCG7vilt/Dph6Rs2EcwYc9BgMFYtM3gSdCLUv4 I+tMEzKtq5KAbamFFvZx7+ti1rXjRJsMZjvz0qerVCMxXjC93hhuyyMUiLAmtzc1/W LR4Z/+Pq0jLyAo39zmyDSxqVjNIeiDuZTxpYCVfdxa8mhWwNuCyhOz1ppbvUAknygE 3GYifpJYvEc3MVOEyQZ5/oL5Xo0WCWkoroRzPUaoRpTDIFj7D2vLbekCufU0BWV8ka oeA1q6H6o0L+DLOpROZC2NULQUuPdxHZ3YYT75nxwHQAPF+Dr37k+z7MxY7tkjCqzh wc8fUODq2yO1Q== Message-ID: <5d441cff-ef78-4bdf-b727-9eb697ca7478@kernel.org> Date: Mon, 26 Oct 2026 22:08:16 +0100 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] hugetlbfs: enforce F_SEAL_EXEC on chmod To: Samiullah Khawaja , Andrew Morton , Muchun Song , Oscar Salvador Cc: Jeff Xu , Daniel Verkamp , David Matlack , Pasha Tatashin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20261026205555.2918396-1-skhawaja@google.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: <20261026205555.2918396-1-skhawaja@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: AE11440005 X-Rspam-User: X-Stat-Signature: fznuhb4qufky1wh9gmu7ng7qnrt67o7b X-Spam-Status: No, score=-17.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam03 X-HE-Tag: 1793048909-188489 X-HE-Meta: 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 khHjknjm FSBPuDyuL5r6o4lzgKEjzDaWinuwLYz4CZhNmOP7HD9ZZuuY3RnOwqtu4MHNX+QixeLfKDomnMxbjseyxt3C5CLWgM6dloUhhZzus6YWcgHOwO4dy8s1dwbZdzR9SDRmQv6ULprkaGHmWyAi+jKqITT2ghRCyzngGEONgXTEDUR1+rr2AmT/lMfcJzQgyxlj8lstIgqAdj8ANwkli65TtmoPlLBHRt8QGaT+qfjGrHxdcbLSm9bhlXnSv3+0vcYYa3jk60ZmuhQbIy8yaYx7YcXMrI16j6lYBqkb5mm3c4mgbcxYfW32ltjxrFl2iiv8sj40jGnwnXoBsmhZuXIwNm/LpRPM9fZQ2N39F 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 10/26/26 21:55, Samiullah Khawaja wrote: > F_SEAL_EXEC prevents the exec bits of a memfd from being changed once > the seal has been set. F_SEAL_EXEC is included in F_ALL_SEALS, so > userspace can set it with F_ADD_SEALS on hugetlbfs memfds just like on > shmem memfds, and F_GET_SEALS then reports it as set. However, the check > that rejects the mode change was only added to shmem_setattr(). > hugetlbfs_setattr() never looks at the seal, so the owner of a sealed > hugetlbfs memfd can still make it executable with chmod(). For the same > reason, MFD_NOEXEC_SEAL provides no guarantee when it is combined with > MFD_HUGETLB. > > The memfd selftest already covers this, but only the shmem run passes. > When run as "memfd_test hugetlbfs", the test aborts in SEAL-EXEC because > fchmod() succeeds on a sealed file, and none of the remaining tests are > executed. > > Add the same check to hugetlbfs_setattr() that shmem_setattr() has, so > that a mode change touching the exec bits fails with -EPERM while > F_SEAL_EXEC is set. > > Fixes: 6fd7353829ca ("mm/memfd: add F_SEAL_EXEC") > Cc: stable@vger.kernel.org > Signed-off-by: Samiullah Khawaja > --- > fs/hugetlbfs/inode.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c > index 01c4d6f44ebe..56e0588d295d 100644 > --- a/fs/hugetlbfs/inode.c > +++ b/fs/hugetlbfs/inode.c > @@ -842,6 +842,10 @@ static int hugetlbfs_setattr(const struct mnt_idmap *idmap, > > trace_hugetlbfs_setattr(inode, dentry, attr); > > + if ((info->seals & F_SEAL_EXEC) && (ia_valid & ATTR_MODE) && > + ((inode->i_mode ^ attr->ia_mode) & 0111)) > + return -EPERM; > + > if (ia_valid & ATTR_SIZE) { > loff_t oldsize = inode->i_size; > loff_t newsize = attr->ia_size; > > base-commit: f1ac44c32cba88ad65dcecd4a279661d14e93651 https://lore.kernel.org/r/20261026-fixes_shmem-v1-5-703206d5fa0c@kernel.org -- Cheers, David