[mirror_ubuntu-artful-kernel.git] / kernel / bpf / inode.c

/*
 * Minimal file system backend for holding eBPF maps and programs,
 * used by bpf(2) object pinning.
 *
 * Authors:
 *
 *	Daniel Borkmann <daniel@iogearbox.net>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 */

#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/kdev_t.h>
#include <linux/parser.h>
#include <linux/filter.h>
#include <linux/bpf.h>
#include <linux/bpf_trace.h>

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

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

static void *bpf_fd_probe_obj(u32 ufd, enum bpf_type *type)
{
	void *raw;

	*type = BPF_TYPE_MAP;
	raw = bpf_map_get_with_uref(ufd);
	if (IS_ERR(raw)) {
		*type = BPF_TYPE_PROG;
		raw = bpf_prog_get(ufd);
	}

	return raw;
}

static const struct inode_operations bpf_dir_iops;

static const struct inode_operations bpf_prog_iops = { };
static const struct inode_operations bpf_map_iops  = { };

static struct inode *bpf_get_inode(struct super_block *sb,
				   const struct inode *dir,
				   umode_t mode)
{
	struct inode *inode;

	switch (mode & S_IFMT) {
	case S_IFDIR:
	case S_IFREG:
	case S_IFLNK:
		break;
	default:
		return ERR_PTR(-EINVAL);
	}

	inode = new_inode(sb);
	if (!inode)
		return ERR_PTR(-ENOSPC);

	inode->i_ino = get_next_ino();
	inode->i_atime = current_time(inode);
	inode->i_mtime = inode->i_atime;
	inode->i_ctime = inode->i_atime;

	inode_init_owner(inode, dir, mode);

	return inode;
}

static int bpf_inode_type(const struct inode *inode, enum bpf_type *type)
{
	*type = BPF_TYPE_UNSPEC;
	if (inode->i_op == &bpf_prog_iops)
		*type = BPF_TYPE_PROG;
	else if (inode->i_op == &bpf_map_iops)
		*type = BPF_TYPE_MAP;
	else
		return -EACCES;

	return 0;
}

static void bpf_dentry_finalize(struct dentry *dentry, struct inode *inode,
				struct inode *dir)
{
	d_instantiate(dentry, inode);
	dget(dentry);

	dir->i_mtime = current_time(dir);
	dir->i_ctime = dir->i_mtime;
}

static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
	struct inode *inode;

	inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFDIR);
	if (IS_ERR(inode))
		return PTR_ERR(inode);

	inode->i_op = &bpf_dir_iops;
	inode->i_fop = &simple_dir_operations;

	inc_nlink(inode);
	inc_nlink(dir);

	bpf_dentry_finalize(dentry, inode, dir);
	return 0;
}

static int bpf_mkobj_ops(struct inode *dir, struct dentry *dentry,
			 umode_t mode, const struct inode_operations *iops)
{
	struct inode *inode;

	inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFREG);
	if (IS_ERR(inode))
		return PTR_ERR(inode);

	inode->i_op = iops;
	inode->i_private = dentry->d_fsdata;

	bpf_dentry_finalize(dentry, inode, dir);
	return 0;
}

static int bpf_mkobj(struct inode *dir, struct dentry *dentry, umode_t mode,
		     dev_t devt)
{
	enum bpf_type type = MINOR(devt);

	if (MAJOR(devt) != UNNAMED_MAJOR || !S_ISREG(mode) ||
	    dentry->d_fsdata == NULL)
		return -EPERM;

	switch (type) {
	case BPF_TYPE_PROG:
		return bpf_mkobj_ops(dir, dentry, mode, &bpf_prog_iops);
	case BPF_TYPE_MAP:
		return bpf_mkobj_ops(dir, dentry, mode, &bpf_map_iops);
	default:
		return -EPERM;
	}
}

static struct dentry *
bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags)
{
	if (strchr(dentry->d_name.name, '.'))
		return ERR_PTR(-EPERM);

	return simple_lookup(dir, dentry, flags);
}

static int bpf_symlink(struct inode *dir, struct dentry *dentry,
		       const char *target)
{
	char *link = kstrdup(target, GFP_USER | __GFP_NOWARN);
	struct inode *inode;

	if (!link)
		return -ENOMEM;

	inode = bpf_get_inode(dir->i_sb, dir, S_IRWXUGO | S_IFLNK);
	if (IS_ERR(inode)) {
		kfree(link);
		return PTR_ERR(inode);
	}

	inode->i_op = &simple_symlink_inode_operations;
	inode->i_link = link;

	bpf_dentry_finalize(dentry, inode, dir);
	return 0;
}

static const struct inode_operations bpf_dir_iops = {
	.lookup		= bpf_lookup,
	.mknod		= bpf_mkobj,
	.mkdir		= bpf_mkdir,
	.symlink	= bpf_symlink,
	.rmdir		= simple_rmdir,
	.rename		= simple_rename,
	.link		= simple_link,
	.unlink		= simple_unlink,
};

static int bpf_obj_do_pin(const struct filename *pathname, void *raw,
			  enum bpf_type type)
{
	struct dentry *dentry;
	struct inode *dir;
	struct path path;
	umode_t mode;
	dev_t devt;
	int ret;

	dentry = kern_path_create(AT_FDCWD, pathname->name, &path, 0);
	if (IS_ERR(dentry))
		return PTR_ERR(dentry);

	mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask());
	devt = MKDEV(UNNAMED_MAJOR, type);

	ret = security_path_mknod(&path, dentry, mode, devt);
	if (ret)
		goto out;

	dir = d_inode(path.dentry);
	if (dir->i_op != &bpf_dir_iops) {
		ret = -EPERM;
		goto out;
	}

	dentry->d_fsdata = raw;
	ret = vfs_mknod(dir, dentry, mode, devt);
	dentry->d_fsdata = NULL;
out:
	done_path_create(&path, dentry);
	return ret;
}

int bpf_obj_pin_user(u32 ufd, const char __user *pathname)
{
	struct filename *pname;
	enum bpf_type type;
	void *raw;
	int ret;

	pname = getname(pathname);
	if (IS_ERR(pname))
		return PTR_ERR(pname);

	raw = bpf_fd_probe_obj(ufd, &type);
	if (IS_ERR(raw)) {
		ret = PTR_ERR(raw);
		goto out;
	}

	ret = bpf_obj_do_pin(pname, raw, type);
	if (ret != 0)
		bpf_any_put(raw, type);
	if ((trace_bpf_obj_pin_prog_enabled() ||
	     trace_bpf_obj_pin_map_enabled()) && !ret) {
		if (type == BPF_TYPE_PROG)
			trace_bpf_obj_pin_prog(raw, ufd, pname);
		if (type == BPF_TYPE_MAP)
			trace_bpf_obj_pin_map(raw, ufd, pname);
	}
out:
	putname(pname);
	return ret;
}

static void *bpf_obj_do_get(const struct filename *pathname,
			    enum bpf_type *type)
{
	struct inode *inode;
	struct path path;
	void *raw;
	int ret;

	ret = kern_path(pathname->name, LOOKUP_FOLLOW, &path);
	if (ret)
		return ERR_PTR(ret);

	inode = d_backing_inode(path.dentry);
	ret = inode_permission(inode, MAY_WRITE);
	if (ret)
		goto out;

	ret = bpf_inode_type(inode, type);
	if (ret)
		goto out;

	raw = bpf_any_get(inode->i_private, *type);
	if (!IS_ERR(raw))
		touch_atime(&path);

	path_put(&path);
	return raw;
out:
	path_put(&path);
	return ERR_PTR(ret);
}

int bpf_obj_get_user(const char __user *pathname)
{
	enum bpf_type type = BPF_TYPE_UNSPEC;
	struct filename *pname;
	int ret = -ENOENT;
	void *raw;

	pname = getname(pathname);
	if (IS_ERR(pname))
		return PTR_ERR(pname);

	raw = bpf_obj_do_get(pname, &type);
	if (IS_ERR(raw)) {
		ret = PTR_ERR(raw);
		goto out;
	}

	if (type == BPF_TYPE_PROG)
		ret = bpf_prog_new_fd(raw);
	else if (type == BPF_TYPE_MAP)
		ret = bpf_map_new_fd(raw);
	else
		goto out;

	if (ret < 0) {
		bpf_any_put(raw, type);
	} else if (trace_bpf_obj_get_prog_enabled() ||
		   trace_bpf_obj_get_map_enabled()) {
		if (type == BPF_TYPE_PROG)
			trace_bpf_obj_get_prog(raw, ret, pname);
		if (type == BPF_TYPE_MAP)
			trace_bpf_obj_get_map(raw, ret, pname);
	}
out:
	putname(pname);
	return ret;
}

static void bpf_evict_inode(struct inode *inode)
{
	enum bpf_type type;

	truncate_inode_pages_final(&inode->i_data);
	clear_inode(inode);

	if (S_ISLNK(inode->i_mode))
		kfree(inode->i_link);
	if (!bpf_inode_type(inode, &type))
		bpf_any_put(inode->i_private, type);
}

/*
 * Display the mount options in /proc/mounts.
 */
static int bpf_show_options(struct seq_file *m, struct dentry *root)
{
	umode_t mode = d_inode(root)->i_mode & S_IALLUGO & ~S_ISVTX;

	if (mode != S_IRWXUGO)
		seq_printf(m, ",mode=%o", mode);
	return 0;
}

static const struct super_operations bpf_super_ops = {
	.statfs		= simple_statfs,
	.drop_inode	= generic_delete_inode,
	.show_options	= bpf_show_options,
	.evict_inode	= bpf_evict_inode,
};

enum {
	OPT_MODE,
	OPT_ERR,
};

static const match_table_t bpf_mount_tokens = {
	{ OPT_MODE, "mode=%o" },
	{ OPT_ERR, NULL },
};

struct bpf_mount_opts {
	umode_t mode;
};

static int bpf_parse_options(char *data, struct bpf_mount_opts *opts)
{
	substring_t args[MAX_OPT_ARGS];
	int option, token;
	char *ptr;

	opts->mode = S_IRWXUGO;

	while ((ptr = strsep(&data, ",")) != NULL) {
		if (!*ptr)
			continue;

		token = match_token(ptr, bpf_mount_tokens, args);
		switch (token) {
		case OPT_MODE:
			if (match_octal(&args[0], &option))
				return -EINVAL;
			opts->mode = option & S_IALLUGO;
			break;
		/* We might like to report bad mount options here, but
		 * traditionally we've ignored all mount options, so we'd
		 * better continue to ignore non-existing options for bpf.
		 */
		}
	}

	return 0;
}

static int bpf_fill_super(struct super_block *sb, void *data, int silent)
{
	static const struct tree_descr bpf_rfiles[] = { { "" } };
	struct bpf_mount_opts opts;
	struct inode *inode;
	int ret;

	ret = bpf_parse_options(data, &opts);
	if (ret)
		return ret;

	ret = simple_fill_super(sb, BPF_FS_MAGIC, bpf_rfiles);
	if (ret)
		return ret;

	sb->s_op = &bpf_super_ops;

	inode = sb->s_root->d_inode;
	inode->i_op = &bpf_dir_iops;
	inode->i_mode &= ~S_IALLUGO;
	inode->i_mode |= S_ISVTX | opts.mode;

	return 0;
}

static struct dentry *bpf_mount(struct file_system_type *type, int flags,
				const char *dev_name, void *data)
{
	return mount_nodev(type, flags, data, bpf_fill_super);
}

static struct file_system_type bpf_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "bpf",
	.mount		= bpf_mount,
	.kill_sb	= kill_litter_super,
};

static int __init bpf_init(void)
{
	int ret;

	ret = sysfs_create_mount_point(fs_kobj, "bpf");
	if (ret)
		return ret;

	ret = register_filesystem(&bpf_fs_type);
	if (ret)
		sysfs_remove_mount_point(fs_kobj, "bpf");

	return ret;
}
fs_initcall(bpf_init);
Commit	Line	Data
b2197755 DB	1	/*
	2	* Minimal file system backend for holding eBPF maps and programs,
	3	* used by bpf(2) object pinning.
	4	*
	5	* Authors:
	6	*
	7	* Daniel Borkmann <daniel@iogearbox.net>
	8	*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License
	11	* version 2 as published by the Free Software Foundation.
	12	*/
	13
a536a6e1	14	#include <linux/init.h>
b2197755 DB	15	#include <linux/magic.h>
	16	#include <linux/major.h>
	17	#include <linux/mount.h>
	18	#include <linux/namei.h>
	19	#include <linux/fs.h>
	20	#include <linux/kdev_t.h>
a3af5f80	21	#include <linux/parser.h>
b2197755 DB	22	#include <linux/filter.h>
b2197755 DB	23	#include <linux/bpf.h>
a67edbf4	24	#include <linux/bpf_trace.h>
b2197755 DB	25
	26	enum bpf_type {
	27	BPF_TYPE_UNSPEC = 0,
	28	BPF_TYPE_PROG,
	29	BPF_TYPE_MAP,
	30	};
	31
	32	static void bpf_any_get(void raw, enum bpf_type type)
	33	{
	34	switch (type) {
	35	case BPF_TYPE_PROG:
92117d84	36	raw = bpf_prog_inc(raw);
b2197755 DB	37	break;
b2197755 DB	38	case BPF_TYPE_MAP:
92117d84	39	raw = bpf_map_inc(raw, true);
b2197755 DB	40	break;
	41	default:
	42	WARN_ON_ONCE(1);
	43	break;
	44	}
	45
	46	return raw;
	47	}
	48
	49	static void bpf_any_put(void *raw, enum bpf_type type)
	50	{
	51	switch (type) {
	52	case BPF_TYPE_PROG:
	53	bpf_prog_put(raw);
	54	break;
	55	case BPF_TYPE_MAP:
c9da161c	56	bpf_map_put_with_uref(raw);
b2197755 DB	57	break;
	58	default:
	59	WARN_ON_ONCE(1);
	60	break;
	61	}
	62	}
	63
	64	static void bpf_fd_probe_obj(u32 ufd, enum bpf_type type)
	65	{
	66	void *raw;
	67
	68	*type = BPF_TYPE_MAP;
c9da161c	69	raw = bpf_map_get_with_uref(ufd);
b2197755 DB	70	if (IS_ERR(raw)) {
	71	*type = BPF_TYPE_PROG;
	72	raw = bpf_prog_get(ufd);
	73	}
	74
	75	return raw;
	76	}
	77
	78	static const struct inode_operations bpf_dir_iops;
	79
	80	static const struct inode_operations bpf_prog_iops = { };
	81	static const struct inode_operations bpf_map_iops = { };
	82
	83	static struct inode bpf_get_inode(struct super_block sb,
	84	const struct inode *dir,
	85	umode_t mode)
	86	{
	87	struct inode *inode;
	88
	89	switch (mode & S_IFMT) {
	90	case S_IFDIR:
	91	case S_IFREG:
0f98621b	92	case S_IFLNK:
b2197755 DB	93	break;
	94	default:
	95	return ERR_PTR(-EINVAL);
	96	}
	97
	98	inode = new_inode(sb);
	99	if (!inode)
	100	return ERR_PTR(-ENOSPC);
	101
	102	inode->i_ino = get_next_ino();
078cd827	103	inode->i_atime = current_time(inode);
b2197755 DB	104	inode->i_mtime = inode->i_atime;
	105	inode->i_ctime = inode->i_atime;
	106
	107	inode_init_owner(inode, dir, mode);
	108
	109	return inode;
	110	}
	111
	112	static int bpf_inode_type(const struct inode inode, enum bpf_type type)
	113	{
	114	*type = BPF_TYPE_UNSPEC;
	115	if (inode->i_op == &bpf_prog_iops)
	116	*type = BPF_TYPE_PROG;
	117	else if (inode->i_op == &bpf_map_iops)
	118	*type = BPF_TYPE_MAP;
	119	else
	120	return -EACCES;
	121
	122	return 0;
	123	}
	124
0f98621b DB	125	static void bpf_dentry_finalize(struct dentry dentry, struct inode inode,
	126	struct inode *dir)
	127	{
	128	d_instantiate(dentry, inode);
	129	dget(dentry);
	130
	131	dir->i_mtime = current_time(dir);
	132	dir->i_ctime = dir->i_mtime;
	133	}
	134
b2197755 DB	135	static int bpf_mkdir(struct inode dir, struct dentry dentry, umode_t mode)
	136	{
	137	struct inode *inode;
	138
b2197755 DB	139	inode = bpf_get_inode(dir->i_sb, dir, mode \| S_IFDIR);
	140	if (IS_ERR(inode))
	141	return PTR_ERR(inode);
	142
	143	inode->i_op = &bpf_dir_iops;
	144	inode->i_fop = &simple_dir_operations;
	145
	146	inc_nlink(inode);
	147	inc_nlink(dir);
	148
0f98621b	149	bpf_dentry_finalize(dentry, inode, dir);
b2197755 DB	150	return 0;
	151	}
	152
	153	static int bpf_mkobj_ops(struct inode dir, struct dentry dentry,
	154	umode_t mode, const struct inode_operations *iops)
	155	{
	156	struct inode *inode;
	157
b2197755 DB	158	inode = bpf_get_inode(dir->i_sb, dir, mode \| S_IFREG);
	159	if (IS_ERR(inode))
	160	return PTR_ERR(inode);
	161
	162	inode->i_op = iops;
	163	inode->i_private = dentry->d_fsdata;
	164
0f98621b	165	bpf_dentry_finalize(dentry, inode, dir);
b2197755 DB	166	return 0;
	167	}
	168
	169	static int bpf_mkobj(struct inode dir, struct dentry dentry, umode_t mode,
	170	dev_t devt)
	171	{
	172	enum bpf_type type = MINOR(devt);
	173
	174	if (MAJOR(devt) != UNNAMED_MAJOR \|\| !S_ISREG(mode) \|\|
	175	dentry->d_fsdata == NULL)
	176	return -EPERM;
	177
	178	switch (type) {
	179	case BPF_TYPE_PROG:
	180	return bpf_mkobj_ops(dir, dentry, mode, &bpf_prog_iops);
	181	case BPF_TYPE_MAP:
	182	return bpf_mkobj_ops(dir, dentry, mode, &bpf_map_iops);
	183	default:
	184	return -EPERM;
	185	}
	186	}
	187
0c93b7d8 AV	188	static struct dentry *
0c93b7d8 AV	189	bpf_lookup(struct inode dir, struct dentry dentry, unsigned flags)
bb35a6ef	190	{
0c93b7d8 AV	191	if (strchr(dentry->d_name.name, '.'))
0c93b7d8 AV	192	return ERR_PTR(-EPERM);
0f98621b	193
0c93b7d8	194	return simple_lookup(dir, dentry, flags);
bb35a6ef DB	195	}
bb35a6ef DB	196
0f98621b DB	197	static int bpf_symlink(struct inode dir, struct dentry dentry,
	198	const char *target)
	199	{
	200	char *link = kstrdup(target, GFP_USER \| __GFP_NOWARN);
	201	struct inode *inode;
	202
	203	if (!link)
	204	return -ENOMEM;
	205
	206	inode = bpf_get_inode(dir->i_sb, dir, S_IRWXUGO \| S_IFLNK);
	207	if (IS_ERR(inode)) {
	208	kfree(link);
	209	return PTR_ERR(inode);
	210	}
	211
	212	inode->i_op = &simple_symlink_inode_operations;
	213	inode->i_link = link;
	214
	215	bpf_dentry_finalize(dentry, inode, dir);
	216	return 0;
	217	}
	218
b2197755	219	static const struct inode_operations bpf_dir_iops = {
0c93b7d8	220	.lookup = bpf_lookup,
b2197755 DB	221	.mknod = bpf_mkobj,
b2197755 DB	222	.mkdir = bpf_mkdir,
0f98621b	223	.symlink = bpf_symlink,
b2197755	224	.rmdir = simple_rmdir,
0c93b7d8 AV	225	.rename = simple_rename,
0c93b7d8 AV	226	.link = simple_link,
b2197755 DB	227	.unlink = simple_unlink,
	228	};
	229
	230	static int bpf_obj_do_pin(const struct filename pathname, void raw,
	231	enum bpf_type type)
	232	{
	233	struct dentry *dentry;
	234	struct inode *dir;
	235	struct path path;
	236	umode_t mode;
	237	dev_t devt;
	238	int ret;
	239
	240	dentry = kern_path_create(AT_FDCWD, pathname->name, &path, 0);
	241	if (IS_ERR(dentry))
	242	return PTR_ERR(dentry);
	243
	244	mode = S_IFREG \| ((S_IRUSR \| S_IWUSR) & ~current_umask());
	245	devt = MKDEV(UNNAMED_MAJOR, type);
	246
	247	ret = security_path_mknod(&path, dentry, mode, devt);
	248	if (ret)
	249	goto out;
	250
	251	dir = d_inode(path.dentry);
	252	if (dir->i_op != &bpf_dir_iops) {
	253	ret = -EPERM;
	254	goto out;
	255	}
	256
	257	dentry->d_fsdata = raw;
	258	ret = vfs_mknod(dir, dentry, mode, devt);
	259	dentry->d_fsdata = NULL;
	260	out:
	261	done_path_create(&path, dentry);
	262	return ret;
	263	}
	264
	265	int bpf_obj_pin_user(u32 ufd, const char __user *pathname)
	266	{
	267	struct filename *pname;
	268	enum bpf_type type;
	269	void *raw;
	270	int ret;
	271
	272	pname = getname(pathname);
	273	if (IS_ERR(pname))
	274	return PTR_ERR(pname);
	275
	276	raw = bpf_fd_probe_obj(ufd, &type);
	277	if (IS_ERR(raw)) {
	278	ret = PTR_ERR(raw);
	279	goto out;
	280	}
	281
	282	ret = bpf_obj_do_pin(pname, raw, type);
	283	if (ret != 0)
	284	bpf_any_put(raw, type);
a67edbf4 DB	285	if ((trace_bpf_obj_pin_prog_enabled() \|\|
	286	trace_bpf_obj_pin_map_enabled()) && !ret) {
	287	if (type == BPF_TYPE_PROG)
	288	trace_bpf_obj_pin_prog(raw, ufd, pname);
	289	if (type == BPF_TYPE_MAP)
	290	trace_bpf_obj_pin_map(raw, ufd, pname);
	291	}
b2197755 DB	292	out:
	293	putname(pname);
	294	return ret;
	295	}
	296
	297	static void bpf_obj_do_get(const struct filename pathname,
	298	enum bpf_type *type)
	299	{
	300	struct inode *inode;
	301	struct path path;
	302	void *raw;
	303	int ret;
	304
	305	ret = kern_path(pathname->name, LOOKUP_FOLLOW, &path);
	306	if (ret)
	307	return ERR_PTR(ret);
	308
	309	inode = d_backing_inode(path.dentry);
	310	ret = inode_permission(inode, MAY_WRITE);
	311	if (ret)
	312	goto out;
	313
	314	ret = bpf_inode_type(inode, type);
	315	if (ret)
	316	goto out;
	317
	318	raw = bpf_any_get(inode->i_private, *type);
92117d84 AS	319	if (!IS_ERR(raw))
92117d84 AS	320	touch_atime(&path);
b2197755 DB	321
	322	path_put(&path);
	323	return raw;
	324	out:
	325	path_put(&path);
	326	return ERR_PTR(ret);
	327	}
	328
	329	int bpf_obj_get_user(const char __user *pathname)
	330	{
	331	enum bpf_type type = BPF_TYPE_UNSPEC;
	332	struct filename *pname;
	333	int ret = -ENOENT;
	334	void *raw;
	335
	336	pname = getname(pathname);
	337	if (IS_ERR(pname))
	338	return PTR_ERR(pname);
	339
	340	raw = bpf_obj_do_get(pname, &type);
	341	if (IS_ERR(raw)) {
	342	ret = PTR_ERR(raw);
	343	goto out;
	344	}
	345
	346	if (type == BPF_TYPE_PROG)
	347	ret = bpf_prog_new_fd(raw);
	348	else if (type == BPF_TYPE_MAP)
	349	ret = bpf_map_new_fd(raw);
	350	else
	351	goto out;
	352
a67edbf4	353	if (ret < 0) {
b2197755	354	bpf_any_put(raw, type);
a67edbf4 DB	355	} else if (trace_bpf_obj_get_prog_enabled() \|\|
	356	trace_bpf_obj_get_map_enabled()) {
	357	if (type == BPF_TYPE_PROG)
	358	trace_bpf_obj_get_prog(raw, ret, pname);
	359	if (type == BPF_TYPE_MAP)
	360	trace_bpf_obj_get_map(raw, ret, pname);
	361	}
b2197755 DB	362	out:
	363	putname(pname);
	364	return ret;
	365	}
	366
	367	static void bpf_evict_inode(struct inode *inode)
	368	{
	369	enum bpf_type type;
	370
	371	truncate_inode_pages_final(&inode->i_data);
	372	clear_inode(inode);
	373
0f98621b DB	374	if (S_ISLNK(inode->i_mode))
0f98621b DB	375	kfree(inode->i_link);
b2197755 DB	376	if (!bpf_inode_type(inode, &type))
	377	bpf_any_put(inode->i_private, type);
	378	}
	379
4cc7c186 DH	380	/*
	381	* Display the mount options in /proc/mounts.
	382	*/
	383	static int bpf_show_options(struct seq_file m, struct dentry root)
	384	{
	385	umode_t mode = d_inode(root)->i_mode & S_IALLUGO & ~S_ISVTX;
	386
	387	if (mode != S_IRWXUGO)
	388	seq_printf(m, ",mode=%o", mode);
	389	return 0;
	390	}
	391
b2197755 DB	392	static const struct super_operations bpf_super_ops = {
	393	.statfs = simple_statfs,
	394	.drop_inode = generic_delete_inode,
4cc7c186	395	.show_options = bpf_show_options,
b2197755 DB	396	.evict_inode = bpf_evict_inode,
	397	};
	398
a3af5f80 DB	399	enum {
	400	OPT_MODE,
	401	OPT_ERR,
	402	};
	403
	404	static const match_table_t bpf_mount_tokens = {
	405	{ OPT_MODE, "mode=%o" },
	406	{ OPT_ERR, NULL },
	407	};
	408
	409	struct bpf_mount_opts {
	410	umode_t mode;
	411	};
	412
	413	static int bpf_parse_options(char data, struct bpf_mount_opts opts)
	414	{
	415	substring_t args[MAX_OPT_ARGS];
	416	int option, token;
	417	char *ptr;
	418
	419	opts->mode = S_IRWXUGO;
	420
	421	while ((ptr = strsep(&data, ",")) != NULL) {
	422	if (!*ptr)
	423	continue;
	424
	425	token = match_token(ptr, bpf_mount_tokens, args);
	426	switch (token) {
	427	case OPT_MODE:
	428	if (match_octal(&args[0], &option))
	429	return -EINVAL;
	430	opts->mode = option & S_IALLUGO;
	431	break;
	432	/* We might like to report bad mount options here, but
	433	* traditionally we've ignored all mount options, so we'd
	434	* better continue to ignore non-existing options for bpf.
	435	*/
	436	}
	437	}
	438
	439	return 0;
	440	}
	441
b2197755 DB	442	static int bpf_fill_super(struct super_block sb, void data, int silent)
b2197755 DB	443	{
cda37124	444	static const struct tree_descr bpf_rfiles[] = { { "" } };
a3af5f80	445	struct bpf_mount_opts opts;
b2197755 DB	446	struct inode *inode;
	447	int ret;
	448
a3af5f80 DB	449	ret = bpf_parse_options(data, &opts);
	450	if (ret)
	451	return ret;
	452
b2197755 DB	453	ret = simple_fill_super(sb, BPF_FS_MAGIC, bpf_rfiles);
	454	if (ret)
	455	return ret;
	456
	457	sb->s_op = &bpf_super_ops;
	458
	459	inode = sb->s_root->d_inode;
	460	inode->i_op = &bpf_dir_iops;
	461	inode->i_mode &= ~S_IALLUGO;
a3af5f80	462	inode->i_mode \|= S_ISVTX \| opts.mode;
b2197755 DB	463
	464	return 0;
	465	}
	466
	467	static struct dentry bpf_mount(struct file_system_type type, int flags,
	468	const char dev_name, void data)
	469	{
e27f4a94	470	return mount_nodev(type, flags, data, bpf_fill_super);
b2197755 DB	471	}
	472
	473	static struct file_system_type bpf_fs_type = {
	474	.owner = THIS_MODULE,
	475	.name = "bpf",
	476	.mount = bpf_mount,
	477	.kill_sb = kill_litter_super,
b2197755 DB	478	};
b2197755 DB	479
b2197755 DB	480	static int __init bpf_init(void)
	481	{
	482	int ret;
	483
	484	ret = sysfs_create_mount_point(fs_kobj, "bpf");
	485	if (ret)
	486	return ret;
	487
	488	ret = register_filesystem(&bpf_fs_type);
	489	if (ret)
	490	sysfs_remove_mount_point(fs_kobj, "bpf");
	491
	492	return ret;
	493	}
	494	fs_initcall(bpf_init);