proc: add LSM hook checks to /proc/<tid>/timerslack_ns

[cascardo/linux.git] / fs / proc / base.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3b792ab..ebccdc1 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2280,16 +2280,25 @@ static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
        if (!p)
                return -ESRCH;
 
-       if (ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)) {
-               task_lock(p);
-               if (slack_ns == 0)
-                       p->timer_slack_ns = p->default_timer_slack_ns;
-               else
-                       p->timer_slack_ns = slack_ns;
-               task_unlock(p);
-       } else
+       if (!capable(CAP_SYS_NICE)) {
                count = -EPERM;
+               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;
+       else
+               p->timer_slack_ns = slack_ns;
+       task_unlock(p);
 
+out:
        put_task_struct(p);
 
        return count;
@@ -2299,19 +2308,26 @@ static int timerslack_ns_show(struct seq_file *m, void *v)
 {
        struct inode *inode = m->private;
        struct task_struct *p;
-       int err =  0;
+       int err = 0;
 
        p = get_proc_task(inode);
        if (!p)
                return -ESRCH;
 
-       if (ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)) {
-               task_lock(p);
-               seq_printf(m, "%llu\n", p->timer_slack_ns);
-               task_unlock(p);
-       } else
+       if (!capable(CAP_SYS_NICE)) {
                err = -EPERM;
+               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);
 
+out:
        put_task_struct(p);
 
        return err;