From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: [PATCH V31 09/25] uswsusp: Disable when the kernel is locked down Date: Tue, 26 Mar 2019 11:27:25 -0700 Message-ID: <20190326182742.16950-10-matthewgarrett@google.com> References: <20190326182742.16950-1-matthewgarrett@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <20190326182742.16950-1-matthewgarrett@google.com> Sender: linux-kernel-owner@vger.kernel.org To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-api@vger.kernel.org, luto@kernel.org, Matthew Garrett , Matthew Garrett , linux-pm@vger.kernel.org, pavel@ucw.cz, rjw@rjwysocki.net List-Id: linux-api@vger.kernel.org From: Matthew Garrett uswsusp allows a user process to dump and then restore kernel state, which makes it possible to modify the running kernel. Disable this if the kernel is locked down. Signed-off-by: David Howells Signed-off-by: Matthew Garrett cc: linux-pm@vger.kernel.org Cc: pavel@ucw.cz Cc: rjw@rjwysocki.net --- kernel/power/user.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/power/user.c b/kernel/power/user.c index 2d8b60a3c86b..99e13fd13237 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -52,6 +52,9 @@ static int snapshot_open(struct inode *inode, struct file *filp) if (!hibernation_available()) return -EPERM; + if (kernel_is_locked_down("/dev/snapshot", LOCKDOWN_INTEGRITY)) + return -EPERM; + lock_system_sleep(); if (!atomic_add_unless(&snapshot_device_available, -1, 0)) { -- 2.21.0.392.gf8f6787159e-goog