selinuxfs.c

Linux Kernel 2.6.9 for OMAP1710

		length = -ERANGE;
		goto out3;
	}

	memcpy(buf, newcon, len);
	length = len;
out3:
	kfree(newcon);
out2:
	kfree(tcon);
out:
	kfree(scon);
	return length;
}

static ssize_t sel_write_user(struct file * file, char *buf, size_t size)
{
	char *con, *user, *ptr;
	u32 sid, *sids;
	ssize_t length;
	char *newcon;
	int i, rc;
	u32 len, nsids;

	length = task_has_security(current, SECURITY__COMPUTE_USER);
	if (length)
		return length;

	length = -ENOMEM;
	con = kmalloc(size+1, GFP_KERNEL);
	if (!con)
		return length;
	memset(con, 0, size+1);

	user = kmalloc(size+1, GFP_KERNEL);
	if (!user)
		goto out;
	memset(user, 0, size+1);

	length = -EINVAL;
	if (sscanf(buf, "%s %s", con, user) != 2)
		goto out2;

	length = security_context_to_sid(con, strlen(con)+1, &sid);
	if (length < 0)
		goto out2;

	length = security_get_user_sids(sid, user, &sids, &nsids);
	if (length < 0)
		goto out2;

	length = sprintf(buf, "%u", nsids) + 1;
	ptr = buf + length;
	for (i = 0; i < nsids; i++) {
		rc = security_sid_to_context(sids[i], &newcon, &len);
		if (rc) {
			length = rc;
			goto out3;
		}
		if ((length + len) >= SIMPLE_TRANSACTION_LIMIT) {
			kfree(newcon);
			length = -ERANGE;
			goto out3;
		}
		memcpy(ptr, newcon, len);
		kfree(newcon);
		ptr += len;
		length += len;
	}
out3:
	kfree(sids);
out2:
	kfree(user);
out:
	kfree(con);
	return length;
}

static struct inode *sel_make_inode(struct super_block *sb, int mode)
{
	struct inode *ret = new_inode(sb);

	if (ret) {
		ret->i_mode = mode;
		ret->i_uid = ret->i_gid = 0;
		ret->i_blksize = PAGE_CACHE_SIZE;
		ret->i_blocks = 0;
		ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
	}
	return ret;
}

#define BOOL_INO_OFFSET 30

static ssize_t sel_read_bool(struct file *filep, char __user *buf,
			     size_t count, loff_t *ppos)
{
	char *page = NULL;
	ssize_t length;
	ssize_t end;
	ssize_t ret;
	int cur_enforcing;
	struct inode *inode;

	down(&sel_sem);

	ret = -EFAULT;

	/* check to see if this file has been deleted */
	if (!filep->f_op)
		goto out;

	if (count < 0 || count > PAGE_SIZE) {
		ret = -EINVAL;
		goto out;
	}
	if (!(page = (char*)get_zeroed_page(GFP_KERNEL))) {
		ret = -ENOMEM;
		goto out;
	}

	inode = filep->f_dentry->d_inode;
	cur_enforcing = security_get_bool_value(inode->i_ino - BOOL_INO_OFFSET);
	if (cur_enforcing < 0) {
		ret = cur_enforcing;
		goto out;
	}

	length = scnprintf(page, PAGE_SIZE, "%d %d", cur_enforcing,
			  bool_pending_values[inode->i_ino - BOOL_INO_OFFSET]);
	if (length < 0) {
		ret = length;
		goto out;
	}

	if (*ppos >= length) {
		ret = 0;
		goto out;
	}
	if (count + *ppos > length)
		count = length - *ppos;
	end = count + *ppos;
	if (copy_to_user(buf, (char *) page + *ppos, count)) {
		ret = -EFAULT;
		goto out;
	}
	*ppos = end;
	ret = count;
out:
	up(&sel_sem);
	if (page)
		free_page((unsigned long)page);
	return ret;
}

static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
			      size_t count, loff_t *ppos)
{
	char *page = NULL;
	ssize_t length = -EFAULT;
	int new_value;
	struct inode *inode;

	down(&sel_sem);

	length = task_has_security(current, SECURITY__SETBOOL);
	if (length)
		goto out;

	/* check to see if this file has been deleted */
	if (!filep->f_op)
		goto out;

	if (count < 0 || count >= PAGE_SIZE) {
		length = -ENOMEM;
		goto out;
	}
	if (*ppos != 0) {
		/* No partial writes. */
		goto out;
	}
	page = (char*)get_zeroed_page(GFP_KERNEL);
	if (!page) {
		length = -ENOMEM;
		goto out;
	}

	if (copy_from_user(page, buf, count))
		goto out;

	length = -EINVAL;
	if (sscanf(page, "%d", &new_value) != 1)
		goto out;

	if (new_value)
		new_value = 1;

	inode = filep->f_dentry->d_inode;
	bool_pending_values[inode->i_ino - BOOL_INO_OFFSET] = new_value;
	length = count;

out:
	up(&sel_sem);
	if (page)
		free_page((unsigned long) page);
	return length;
}

static struct file_operations sel_bool_ops = {
	.read           = sel_read_bool,
	.write          = sel_write_bool,
};

static ssize_t sel_commit_bools_write(struct file *filep,
				      const char __user *buf,
				      size_t count, loff_t *ppos)
{
	char *page = NULL;
	ssize_t length = -EFAULT;
	int new_value;

	down(&sel_sem);

	length = task_has_security(current, SECURITY__SETBOOL);
	if (length)
		goto out;

	/* check to see if this file has been deleted */
	if (!filep->f_op)
		goto out;

	if (count < 0 || count >= PAGE_SIZE) {
		length = -ENOMEM;
		goto out;
	}
	if (*ppos != 0) {
		/* No partial writes. */
		goto out;
	}
	page = (char*)get_zeroed_page(GFP_KERNEL);
	if (!page) {
		length = -ENOMEM;
		goto out;
	}

	if (copy_from_user(page, buf, count))
		goto out;

	length = -EINVAL;
	if (sscanf(page, "%d", &new_value) != 1)
		goto out;

	if (new_value) {
		security_set_bools(bool_num, bool_pending_values);
	}

	length = count;

out:
	up(&sel_sem);
	if (page)
		free_page((unsigned long) page);
	return length;
}

static struct file_operations sel_commit_bools_ops = {
	.write          = sel_commit_bools_write,
};

/* delete booleans - partial revoke() from
 * fs/proc/generic.c proc_kill_inodes */
static void sel_remove_bools(struct dentry *de)
{
	struct list_head *p, *node;
	struct super_block *sb = de->d_sb;

	spin_lock(&dcache_lock);
	node = de->d_subdirs.next;
	while (node != &de->d_subdirs) {
		struct dentry *d = list_entry(node, struct dentry, d_child);
		list_del_init(node);

		if (d->d_inode) {
			d = dget_locked(d);
			spin_unlock(&dcache_lock);
			d_delete(d);
			simple_unlink(de->d_inode, d);
			dput(d);
			spin_lock(&dcache_lock);
		}
		node = de->d_subdirs.next;
	}

	spin_unlock(&dcache_lock);

	file_list_lock();
	list_for_each(p, &sb->s_files) {
		struct file * filp = list_entry(p, struct file, f_list);
		struct dentry * dentry = filp->f_dentry;

		if (dentry->d_parent != de) {
			continue;
		}
		filp->f_op = NULL;
	}
	file_list_unlock();
}

#define BOOL_DIR_NAME "booleans"

static int sel_make_bools(void)
{
	int i, ret = 0;
	ssize_t len;
	struct dentry *dentry = NULL;
	struct dentry *dir = bool_dir;
	struct inode *inode = NULL;
	struct inode_security_struct *isec;
	struct qstr qname;
	char **names = NULL, *page;
	int num;
	int *values = NULL;
	u32 sid;

	/* remove any existing files */
	if (bool_pending_values)
		kfree(bool_pending_values);

	sel_remove_bools(dir);

	if (!(page = (char*)get_zeroed_page(GFP_KERNEL)))
		return -ENOMEM;

	ret = security_get_bools(&num, &names, &values);
	if (ret != 0)
		goto out;

	for (i = 0; i < num; i++) {
		qname.name = names[i];
		qname.len = strlen(qname.name);
		qname.hash = full_name_hash(qname.name, qname.len);
		dentry = d_alloc(dir, &qname);
		if (!dentry) {
			ret = -ENOMEM;
			goto err;
		}
		inode = sel_make_inode(dir->d_sb, S_IFREG | S_IRUGO | S_IWUSR);
		if (!inode) {
			ret = -ENOMEM;
			goto err;
		}

		len = snprintf(page, PAGE_SIZE, "/%s/%s", BOOL_DIR_NAME, names[i]);
		if (len < 0) {
			ret = -EINVAL;
			goto err;
		} else if (len >= PAGE_SIZE) {
			ret = -ENAMETOOLONG;
			goto err;
		}
		isec = (struct inode_security_struct*)inode->i_security;
		if ((ret = security_genfs_sid("selinuxfs", page, SECCLASS_FILE, &sid)))
			goto err;
		isec->sid = sid;
		isec->initialized = 1;
		inode->i_fop = &sel_bool_ops;
		inode->i_ino = i + BOOL_INO_OFFSET;
		d_add(dentry, inode);
	}
	bool_num = num;
	bool_pending_values = values;
out:
	free_page((unsigned long)page);
	if (names) {
		for (i = 0; i < num; i++) {
			if (names[i])
				kfree(names[i]);
		}
		kfree(names);
	}
	return ret;
err:
	d_genocide(dir);
	ret = -ENOMEM;
	goto out;
}

#define NULL_FILE_NAME "null"

struct dentry *selinux_null = NULL;

static int sel_fill_super(struct super_block * sb, void * data, int silent)
{
	int ret;
	struct dentry *dentry;
	struct inode *inode;
	struct qstr qname;
	struct inode_security_struct *isec;

	static struct tree_descr selinux_files[] = {
		[SEL_LOAD] = {"load", &sel_load_ops, S_IRUSR|S_IWUSR},
		[SEL_ENFORCE] = {"enforce", &sel_enforce_ops, S_IRUGO|S_IWUSR},
		[SEL_CONTEXT] = {"context", &sel_context_ops, S_IRUGO|S_IWUGO},
		[SEL_ACCESS] = {"access", &transaction_ops, S_IRUGO|S_IWUGO},
		[SEL_CREATE] = {"create", &transaction_ops, S_IRUGO|S_IWUGO},
		[SEL_RELABEL] = {"relabel", &transaction_ops, S_IRUGO|S_IWUGO},
		[SEL_USER] = {"user", &transaction_ops, S_IRUGO|S_IWUGO},
		[SEL_POLICYVERS] = {"policyvers", &sel_policyvers_ops, S_IRUGO},
		[SEL_COMMIT_BOOLS] = {"commit_pending_bools", &sel_commit_bools_ops, S_IWUSR},
		[SEL_MLS] = {"mls", &sel_mls_ops, S_IRUGO},
		[SEL_DISABLE] = {"disable", &sel_disable_ops, S_IWUSR},
		/* last one */ {""}
	};
	ret = simple_fill_super(sb, SELINUX_MAGIC, selinux_files);
	if (ret)
		return ret;

	qname.name = BOOL_DIR_NAME;
	qname.len = strlen(qname.name);
	qname.hash = full_name_hash(qname.name, qname.len);
	dentry = d_alloc(sb->s_root, &qname);
	if (!dentry)
		return -ENOMEM;

	inode = sel_make_inode(sb, S_IFDIR | S_IRUGO | S_IXUGO);
	if (!inode)
		goto out;
	inode->i_op = &simple_dir_inode_operations;
	inode->i_fop = &simple_dir_operations;
	d_add(dentry, inode);
	bool_dir = dentry;
	ret = sel_make_bools();
	if (ret)
		goto out;

	qname.name = NULL_FILE_NAME;
	qname.len = strlen(qname.name);
	qname.hash = full_name_hash(qname.name, qname.len);
	dentry = d_alloc(sb->s_root, &qname);
	if (!dentry)
		return -ENOMEM;

	inode = sel_make_inode(sb, S_IFCHR | S_IRUGO | S_IWUGO);
	if (!inode)
		goto out;
	isec = (struct inode_security_struct*)inode->i_security;
	isec->sid = SECINITSID_DEVNULL;
	isec->sclass = SECCLASS_CHR_FILE;
	isec->initialized = 1;

	init_special_inode(inode, S_IFCHR | S_IRUGO | S_IWUGO, MKDEV(MEM_MAJOR, 3));
	d_add(dentry, inode);
	selinux_null = dentry;

	return 0;
out:
	dput(dentry);
	printk(KERN_ERR "%s:  failed while creating inodes\n", __FUNCTION__);
	return -ENOMEM;
}

static struct super_block *sel_get_sb(struct file_system_type *fs_type,
				      int flags, const char *dev_name, void *data)
{
	return get_sb_single(fs_type, flags, data, sel_fill_super);
}

static struct file_system_type sel_fs_type = {
	.name		= "selinuxfs",
	.get_sb		= sel_get_sb,
	.kill_sb	= kill_litter_super,
};

struct vfsmount *selinuxfs_mount;

static int __init init_sel_fs(void)
{
	int err;

	if (!selinux_enabled)
		return 0;
	err = register_filesystem(&sel_fs_type);
	if (!err) {
		selinuxfs_mount = kern_mount(&sel_fs_type);
		if (IS_ERR(selinuxfs_mount)) {
			printk(KERN_ERR "selinuxfs:  could not mount!\n");
			err = PTR_ERR(selinuxfs_mount);
			selinuxfs_mount = NULL;
		}
	}
	return err;
}

__initcall(init_sel_fs);

#ifdef CONFIG_SECURITY_SELINUX_DISABLE
void exit_sel_fs(void)
{
	unregister_filesystem(&sel_fs_type);
}
#endif