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Tue, 10 Nov 2026 09:17:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794302280; bh=8foKI6JmuMCwlgA1vbndmP56m7vz0lsh+SJERlRxyTw=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=dmhfQG5Wa9F1vl+Ncla7LH9qR2Pb19MWVA960fv/qPgnC3PfvrweEc5lpNq7tg5cv X5jebb+YDcv3+oNILPlH9pzpQZuHd5gXnfWtjGHFm2sCmt+GLljdrB8ed3e2EDVoxW 6qwLDDuejmnmabFf6S4yipLYILlMtcgi/B3PaMm2jtiYlDVjoc2AfZI3TB5b25URyB 9JqF6aBLQhF8lrePFMLHHrz/X2m11imH2EHUNar9GCgoanthwCkg9zDKmfEF8OQXN7 FbpquhbOcx9HJMB4de2od2c6Rsbmt4mVOK3tjcZbRaBQ7AHeFHK8pVFWivdn0ZmDS9 s18yL7iJzQ1pg== From: Christian Brauner Date: Tue, 10 Nov 2026 10:14:34 +0100 Subject: [PATCH RFC 18/41] selinux: use fc_init_pseudo() for selinuxfs X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , Precedence: list X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261110-work-loop-pseudo-v1-18-4c998976c6c7@kernel.org> References: <20261110-work-loop-pseudo-v1-0-4c998976c6c7@kernel.org> In-Reply-To: <20261110-work-loop-pseudo-v1-0-4c998976c6c7@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: Jann Horn , Chris Mason , Josef Bacik , Christoph Hellwig , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Alexander Viro , Jan Kara , linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, driver-core@lists.linux.dev, linux-mm@kvack.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, apparmor@lists.ubuntu.com, linux-nfs@vger.kernel.org, netdev@vger.kernel.org, fuse-devel@lists.linux.dev, linux-efi@vger.kernel.org, xen-devel@lists.xenproject.org, ocfs2-devel@lists.linux.dev, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-usb@vger.kernel.org, Amir Goldstein , linux-erofs@lists.ozlabs.org, linux-kselftest@vger.kernel.org, "Christian Brauner (Amutable)" X-Mailer: b4 0.17-dev-ce4c1 X-Developer-Signature: v=1; a=openpgp-sha256; l=1631; i=brauner@kernel.org; h=from:subject:message-id; bh=G6GyKhtPUuEHs5LrXzW88WAPZ6YLQCvHyquwK5OU8Mc=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWR9erCSv4OpQlCv+sKCEKYLJnl7XiQuW3g/KvNGSuDNm Z9Edkzu6yhlYRDjYpAVU2RxaDcJl1vOU7HZKFMDZg4rE8gQBi5OAZhIwRJGho3heV555heiU9OC joYteqa/h+mn21yLC5/8Vn9e8++ltjrDfz95yYxJLSHu6Y6WLBnlx5eIrDRyi2Wcy6Ybt7PmXsR WHgA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 X-Spam-Status: No, score=-18.8 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_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Initialize selinuxfs as a pseudo filesystem. This raises SB_I_PSEUDO and SB_I_NOEXEC. selinuxfs never holds executables. SB_I_NOEXEC also refuses PROT_EXEC mappings but the status and policy files are only ever mapped for reading. But selinuxfs needs device nodes. The kernel replaces file descriptors with /sys/fs/selinux/null on exec via dentry_open() which doesn't care about SB_I_NODEV. Android init however opens /sys/fs/selinux/null by path as /dev/null doesn't exist yet at that point. So clear SB_I_NODEV again in sel_fill_super(). Signed-off-by: Christian Brauner (Amutable) --- security/selinux/selinuxfs.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 310e19efff1d..d7ae853b6d68 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -1852,6 +1853,9 @@ static int sel_fill_super(struct super_block *sb, struct fs_context *fc) /* last one */ {"", NULL, 0} }; + /* Android init opens the null device below by path. */ + sb->s_iflags &= ~SB_I_NODEV; + ret = selinux_fs_info_create(sb); if (ret) goto err; @@ -1955,6 +1959,7 @@ static const struct fs_context_operations sel_context_ops = { static int sel_init_fs_context(struct fs_context *fc) { + fc_init_pseudo(fc); fc->ops = &sel_context_ops; return 0; } -- 2.53.0