Commit 868f31e4 authored by Stephen Smalley's avatar Stephen Smalley Committed by Paul Moore
Browse files

selinux: shrink critical section in sel_write_load() 



Currently sel_write_load() takes the policy mutex earlier than
necessary. Move the taking of the mutex later. This avoids
holding it unnecessarily across the vmalloc() and copy_from_user()
of the policy data.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarStephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent a02cd680

security/selinux/selinuxfs.c

+8 −10
Original line number Diff line number Diff line
@@ -553,34 +553,31 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf, 
	if (!count)

		return -EINVAL;



	mutex_lock(&selinux_state.policy_mutex);



	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,

			      SECCLASS_SECURITY, SECURITY__LOAD_POLICY, NULL);

	if (length)

		goto out;

		return length;



	data = vmalloc(count);

	if (!data) {

		length = -ENOMEM;

		goto out;

	}

	if (!data)

		return -ENOMEM;

	if (copy_from_user(data, buf, count) != 0) {

		length = -EFAULT;

		goto out;

	}



	mutex_lock(&selinux_state.policy_mutex);

	length = security_load_policy(data, count, &load_state);

	if (length) {

		pr_warn_ratelimited("SELinux: failed to load policy\n");

		goto out;

		goto out_unlock;

	}

	fsi = file_inode(file)->i_sb->s_fs_info;

	length = sel_make_policy_nodes(fsi, load_state.policy);

	if (length) {

		pr_warn_ratelimited("SELinux: failed to initialize selinuxfs\n");

		selinux_policy_cancel(&load_state);

		goto out;

		goto out_unlock;

	}



	selinux_policy_commit(&load_state);
@@ -590,8 +587,9 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf, 
		from_kuid(&init_user_ns, audit_get_loginuid(current)),

		audit_get_sessionid(current));



out:

out_unlock:

	mutex_unlock(&selinux_state.policy_mutex);

out:

	vfree(data);

	return length;

}