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[52.70.167.183]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4b0733088e1sm153587391cf.61.2025.08.14.06.27.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Aug 2025 06:27:42 -0700 (PDT) From: Stephen Smalley To: selinux@vger.kernel.org Cc: paul@paul-moore.com, omosnace@redhat.com, netdev@vger.kernel.org, horms@kernel.org, Stephen Smalley Subject: [PATCH v7 42/42] selinux: disallow writes to /sys/fs/selinux/user in non-init namespaces Date: Thu, 14 Aug 2025 09:26:33 -0400 Message-ID: <20250814132637.1659-43-stephen.smalley.work@gmail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250814132637.1659-1-stephen.smalley.work@gmail.com> References: <20250814132637.1659-1-stephen.smalley.work@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Disallow writes to /sys/fs/selinux/user in non-init SELinux namespaces. Signed-off-by: Stephen Smalley --- security/selinux/selinuxfs.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index b1ce3a98a241..f847767e5e15 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -1371,10 +1371,20 @@ static ssize_t sel_write_user(struct file *file, char *buf, size_t size) int rc; u32 i, len, nsids; - pr_warn_ratelimited("SELinux: %s (%d) wrote to /sys/fs/selinux/user!" - " This will not be supported in the future; please update your" - " userspace.\n", current->comm, current->pid); - ssleep(5); + if (state == init_selinux_state) { + pr_warn_ratelimited("SELinux: %s (%d) wrote to" + " /sys/fs/selinux/user! This will not be" + " supported in the future; please update your" + " userspace.\n", current->comm, current->pid); + ssleep(5); + } else { + pr_warn_ratelimited("SELinux: %s (%d) tried to write to" + " /sys/fs/selinux/user! This is not supported" + " in non-init SELinux namespaces; please" + " update your userspace.\n", current->comm, + current->pid); + return -EPERM; + } /* * Only check against the current namespace because -- 2.50.1