path: root/kernel/bpf/inode.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Minimal file system backend for holding eBPF maps and programs,
 * used by bpf(2) object pinning.
 *
 * Authors:
 *
 *	Daniel Borkmann <daniel@iogearbox.net>
 */

#include <linux/init.h>
#include <linux/magic.h>
#include <linux/major.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/fs.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/kdev_t.h>
#include <linux/filter.h>
#include <linux/bpf.h>
#include <linux/bpf_trace.h>
#include <linux/kstrtox.h>
#include <linux/xattr.h>
#include <linux/security.h>

#include "preload/bpf_preload.h"

enum bpf_type {
	BPF_TYPE_UNSPEC	= 0,
	BPF_TYPE_PROG,
	BPF_TYPE_MAP,
	BPF_TYPE_LINK,
};

struct bpf_fs_inode {
	struct list_head		xattrs;
	struct simple_xattr_limits	xlimits;
	struct inode			vfs_inode;
};

static inline struct bpf_fs_inode *BPF_FS_I(struct inode *inode)
{
	return container_of(inode, struct bpf_fs_inode, vfs_inode);
}

static struct kmem_cache *bpf_fs_inode_cachep __ro_after_init;

static int bpf_fs_initxattrs(struct inode *inode,
			     const struct xattr *xattr_array, void *fs_info);
static ssize_t bpf_fs_listxattr(struct dentry *dentry, char *buf, size_t size);

static void *bpf_any_get(void *raw, enum bpf_type type)
{
	switch (type) {
	case BPF_TYPE_PROG:
		bpf_prog_inc(raw);
		break;
	case BPF_TYPE_MAP:
		bpf_map_inc_with_uref(raw);
		break;
	case BPF_TYPE_LINK:
		bpf_link_inc(raw);
		break;
	default:
		WARN_ON_ONCE(1);
		break;
	}

	return raw;
}

static void bpf_any_put(void *raw, enum bpf_type type)
{
	switch (type) {
	case BPF_TYPE_PROG:
		bpf_prog_put(raw);
		break;
	case BPF_TYPE_MAP:
		bpf_map_put_with_uref(raw);
		break;
	case BPF_TYPE_LINK:
		bpf_link_put(raw);
		break;
	default:
		WARN_ON_ONCE(1);
		break;
	}
}

static void *