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[73.67.244.238]) by smtp.gmail.com with ESMTPSA id d185sm14277920pfd.80.2016.07.21.13.24.30 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 21 Jul 2016 13:24:31 -0700 (PDT) From: John Stultz To: lkml Cc: John Stultz , Kees Cook , "Serge E. Hallyn" , Andrew Morton , Thomas Gleixner , Arjan van de Ven , Oren Laadan , Ruchi Kandoi , Rom Lemarchand , Todd Kjos , Colin Cross , Nick Kralevich , Dmitry Shmidt , Elliott Hughes , James Morris , Android Kernel Team , linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov Subject: [PATCH 2/2 v4] proc: Add LSM hook checks to /proc//timerslack_ns Date: Thu, 21 Jul 2016 13:24:27 -0700 Message-Id: <1469132667-17377-2-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1469132667-17377-1-git-send-email-john.stultz@linaro.org> References: <1469132667-17377-1-git-send-email-john.stultz@linaro.org> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP 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 Cc: "Serge E. Hallyn" Cc: Andrew Morton Cc: Thomas Gleixner CC: Arjan van de Ven Cc: Oren Laadan Cc: Ruchi Kandoi Cc: Rom Lemarchand Cc: Todd Kjos Cc: Colin Cross Cc: Nick Kralevich Cc: Dmitry Shmidt Cc: Elliott Hughes Cc: James Morris Cc: Android Kernel Team Cc: linux-security-module@vger.kernel.org Cc: selinux@tycho.nsa.gov Signed-off-by: John Stultz Acked-by: Paul Moore --- 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(+) 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);