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b=RYN2vzKs4ZkzsggRNOd5345Y9RmP5xJuwIVm9w6r5x3FAJg1HBumtJ7kzq7Zk2Byv NJLY3MTki5J/jgMKffKX0MJUDmrh7Mj9/0LUeDWRGFT9PKDun2MDUk4bswpvOBod5/ bNYMieVVAxa9BIH2qgUZj85frA0Pfn970M2GP/0jc91EGPQZNOIAGmiPNiger8wclo ufyI4lp/osGtIkHDTUYogUM4fs20J692aYPNRbVq5x2xvqh4gPgqRcUB13BB9b5qSK oNjI1xXwG20lYigNS/pYDFW4KUWITLyuatPQ7hVvva5pYJEnM36h88Ce4pzq4aw8J6 m+957JU9t5eOA== From: Pratyush Yadav To: "David Hildenbrand (Arm)" Cc: Andrew Morton , Gregory Price , Zi Yan , Joshua Hahn , Rakie Kim , Ying Huang , Johannes Weiner , Vladimir Davydov , Michal Hocko , Hugh Dickins , Baolin Wang , Lukas Czerner , Carlos Maiolino , Christian Brauner , Jan Kara , Daniel Verkamp , Jeff Xu , Muchun Song , Oscar Salvador , David Stevens , "Matthew Wilcox (Oracle)" , William Kucharski , Chris Li , Kairui Song , Nhat Pham , Miaohe Lin , Naoya Horiguchi , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Chris Mason , stable@vger.kernel.org, Pedro Falcato , "Kiryl Shutsemau (Meta)" Subject: Re: [PATCH v2 04/14] mm/shmem: honour F_SEAL_EXEC when an ACL is set In-Reply-To: <20261027-fixes_shmem-v2-4-86a00952acb9@kernel.org> (David Hildenbrand's message of "Tue, 27 Oct 2026 14:03:09 +0100") References: <20261027-fixes_shmem-v2-0-86a00952acb9@kernel.org> <20261027-fixes_shmem-v2-4-86a00952acb9@kernel.org> Date: Tue, 27 Oct 2026 18:34:18 +0100 Message-ID: <2vxz7bj3oxnp.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: 00C2B40008 X-Rspam-User: X-Stat-Signature: deh5rrsoqiixnxq75w571desossmimka X-Spam-Status: No, score=-12.6 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=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam03 X-HE-Tag: 1793122465-519695 X-HE-Meta: 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 XEUAU88t KvLHGth6Y8o0DxRmFDeLoLOoW40OyRVnyzv7JlvvNvPnGNQ34NvzdWjXofaZ0Tks6mt4Ky1iI7cwdgdsIoB6btaUGibppVSsMXQQbzJszPB7Kv1Ptn1K9Bf8FUTFf2Wbj+jbQRBdsNp6HLIbHXoQDTm96IIKE4MhTHKGBl5sJ5Bpd/59r7rupWeqYOQjZp7gUW0szdP97YJV/UlCj+G1hEFInpwlGdmNZwNsfiFIJ/4ljWBcAsVAXpPzbj5Gyzn2m8nn/esZ1AawzX+CJdaIp5GrN3/y2KiJRPsRZy53RR6qWAtFQ46Pvw05EDQegd8gmPEdn3L+j0F/43Q8+WXwyaN3o3VZDS99zCWP1jyfyQOgghJfS1xdw/XiuJr7KApnDt/MR6BLWb0W3I7F5RIsWJI9ts9iqE7/Zh0M9M6Ejljh79Zztihn3Ug+m2aaZTuEVIy645xhgQBEbeaP94RF7h09Y5g== 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 Tue, Oct 27 2026, David Hildenbrand (Arm) wrote: > From: Chris Mason > > The owner of a memfd sealed with F_SEAL_EXEC can still change its > execute bits by setting a POSIX access ACL. With CONFIG_TMPFS_POSIX_ACL, > this lets an unprivileged owner make a non-executable memfd executable, > bypassing vm.memfd_noexec=2. > > simple_set_acl() updates i_mode directly, bypassing the seal check in > shmem_setattr(). Add shmem_set_acl() to check the resulting mode. Share > the F_SEAL_EXEC check with shmem_setattr() using memfd_check_seals_mode() > in include/linux/memfd.h. > > Fix generated by an LLM and sent by Chris Mason in private. > > Fixes: 6fd7353829ca ("mm/memfd: add F_SEAL_EXEC") > Cc: stable@vger.kernel.org > Signed-off-by: Chris Mason > Acked-by: Pedro Falcato > Acked-by: Kiryl Shutsemau (Meta) > Acked-by: Zi Yan > Reviewed-by: Baolin Wang > Tested-by: Gregory Price (Meta) > [ david: use common helper; simplify description ] > Signed-off-by: David Hildenbrand (Arm) Reviewed-by: Pratyush Yadav (Google) [...] -- Regards, Pratyush Yadav