Commit ea49d10e authored Nov 18, 2016 by Stephen Smalley Committed by Paul Moore Nov 20, 2016

selinux: normalize input to /sys/fs/selinux/enforce



At present, one can write any signed integer value to
/sys/fs/selinux/enforce and it will be stored,
e.g. echo -1 > /sys/fs/selinux/enforce or echo 2 >
/sys/fs/selinux/enforce. This makes no real difference
to the kernel, since it only ever cares if it is zero or non-zero,
but some userspace code compares it with 1 to decide if SELinux
is enforcing, and this could confuse it. Only a process that is
already root and is allowed the setenforce permission in SELinux
policy can write to /sys/fs/selinux/enforce, so this is not considered
to be a security issue, but it should be fixed.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>

parent 13457d07

security/selinux/selinuxfs.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -163,6 +163,8 @@ static ssize_t sel_write_enforce(struct file file, const char __user buf,
		if (sscanf(page, "%d", &new_value) != 1)
		goto out;

		new_value = !!new_value;

		if (new_value != selinux_enforcing) {
		length = task_has_security(current, SECURITY__SETENFORCE);
		if (length)