Commit 42c77323 authored by Paul Moore's avatar Paul Moore
Browse files

selinux: improve error checking in sel_write_load() 



Move our existing input sanity checking to the top of sel_write_load()
and add a check to ensure the buffer size is non-zero.

Move a local variable initialization from the declaration to before it
is used.

Minor style adjustments.

Reported-by: default avatarSam Sun <samsun1006219@gmail.com>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent e6b5ebca

security/selinux/selinuxfs.c

+16 −14
Original line number Diff line number Diff line
@@ -571,11 +571,18 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf, 
			      size_t count, loff_t *ppos)



{

	struct selinux_fs_info *fsi = file_inode(file)->i_sb->s_fs_info;

	struct selinux_fs_info *fsi;

	struct selinux_load_state load_state;

	ssize_t length;

	void *data = NULL;



	/* no partial writes */

	if (*ppos)

		return -EINVAL;

	/* no empty policies */

	if (!count)

		return -EINVAL;



	mutex_lock(&selinux_state.policy_mutex);



	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
@@ -583,26 +590,22 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf, 
	if (length)

		goto out;



	/* No partial writes. */

	length = -EINVAL;

	if (*ppos != 0)

		goto out;



	length = -ENOMEM;

	data = vmalloc(count);

	if (!data)

	if (!data) {

		length = -ENOMEM;

		goto out;



	}

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

		length = -EFAULT;

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

		goto out;

	}



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

	if (length) {

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

		goto out;

	}



	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");
@@ -611,13 +614,12 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf, 
	}



	selinux_policy_commit(&load_state);



	length = count;



	audit_log(audit_context(), GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,

		"auid=%u ses=%u lsm=selinux res=1",

		from_kuid(&init_user_ns, audit_get_loginuid(current)),

		audit_get_sessionid(current));



out:

	mutex_unlock(&selinux_state.policy_mutex);

	vfree(data);