| Message ID | 1469132667-17377-2-git-send-email-john.stultz@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Wed, Aug 17, 2016 at 2:21 PM, Paul Moore <paul@paul-moore.com> wrote: > On Thu, Jul 21, 2016 at 4:24 PM, John Stultz <john.stultz@linaro.org> wrote: >> As requested, this patch checks the existing LSM hooks >> task_getscheduler/task_setscheduler when reading or modifying >> the task's timerslack value. >> >> Previous versions added new get/settimerslack LSM hooks, but >> since they checked the same PROCESS__SET/GETSCHED values as >> existing hooks, it was suggested we just use the existing ones. >> >> Cc: Kees Cook <keescook@chromium.org> >> Cc: "Serge E. Hallyn" <serge@hallyn.com> >> Cc: Andrew Morton <akpm@linux-foundation.org> >> Cc: Thomas Gleixner <tglx@linutronix.de> >> CC: Arjan van de Ven <arjan@linux.intel.com> >> Cc: Oren Laadan <orenl@cellrox.com> >> Cc: Ruchi Kandoi <kandoiruchi@google.com> >> Cc: Rom Lemarchand <romlem@android.com> >> Cc: Todd Kjos <tkjos@google.com> >> Cc: Colin Cross <ccross@android.com> >> Cc: Nick Kralevich <nnk@google.com> >> Cc: Dmitry Shmidt <dimitrysh@google.com> >> Cc: Elliott Hughes <enh@google.com> >> Cc: James Morris <jmorris@namei.org> >> Cc: Android Kernel Team <kernel-team@android.com> >> Cc: linux-security-module@vger.kernel.org >> Cc: selinux@tycho.nsa.gov >> Signed-off-by: John Stultz <john.stultz@linaro.org> >> --- >> v2: >> * Initial swing at adding settimerslack LSM hook >> v3: >> * Fix current/p switchup bug noted by NickK >> * Add gettimerslack hook suggested by NickK >> v4: >> * Dropped adding get/settimerslack LSM hooks, and >> just reuse the get/setscheduler ones. >> >> fs/proc/base.c | 10 ++++++++++ >> 1 file changed, 10 insertions(+) > > For some reason I'm having a hard time finding patch 1/2 in the > patchset, but this patch looks reasonable to me. We already have some https://lkml.org/lkml/2016/7/21/522 > LSM checking via the ptrace_may_access() call, but this adds some > additional granularity which could be a good thing. > > Acked-by: Paul Moore <paul@paul-moore.com> Thanks. There's also this follow-on patch (and discussion thread) that adds a fix to the 1/2 patch linked above. https://lkml.org/lkml/2016/8/9/876 thanks -john
diff --git a/fs/proc/base.c b/fs/proc/base.c index c94abae..02f8389 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2286,6 +2286,12 @@ static ssize_t timerslack_ns_write(struct file *file, const char __user *buf, goto out; } + err = security_task_setscheduler(p); + if (err) { + count = err; + goto out; + } + task_lock(p); if (slack_ns == 0) p->timer_slack_ns = p->default_timer_slack_ns; @@ -2314,6 +2320,10 @@ static int timerslack_ns_show(struct seq_file *m, void *v) goto out; } + err = security_task_getscheduler(p); + if (err) + goto out; + task_lock(p); seq_printf(m, "%llu\n", p->timer_slack_ns); task_unlock(p);
As requested, this patch checks the existing LSM hooks task_getscheduler/task_setscheduler when reading or modifying the task's timerslack value. Previous versions added new get/settimerslack LSM hooks, but since they checked the same PROCESS__SET/GETSCHED values as existing hooks, it was suggested we just use the existing ones. Cc: Kees Cook <keescook@chromium.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> CC: Arjan van de Ven <arjan@linux.intel.com> Cc: Oren Laadan <orenl@cellrox.com> Cc: Ruchi Kandoi <kandoiruchi@google.com> Cc: Rom Lemarchand <romlem@android.com> Cc: Todd Kjos <tkjos@google.com> Cc: Colin Cross <ccross@android.com> Cc: Nick Kralevich <nnk@google.com> Cc: Dmitry Shmidt <dimitrysh@google.com> Cc: Elliott Hughes <enh@google.com> Cc: James Morris <jmorris@namei.org> Cc: Android Kernel Team <kernel-team@android.com> Cc: linux-security-module@vger.kernel.org Cc: selinux@tycho.nsa.gov Signed-off-by: John Stultz <john.stultz@linaro.org> --- v2: * Initial swing at adding settimerslack LSM hook v3: * Fix current/p switchup bug noted by NickK * Add gettimerslack hook suggested by NickK v4: * Dropped adding get/settimerslack LSM hooks, and just reuse the get/setscheduler ones. fs/proc/base.c | 10 ++++++++++ 1 file changed, 10 insertions(+) -- 1.9.1