[linux-block.git] / kernel / bpf / map_iter.c

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2020 Facebook */
#include <linux/bpf.h>
#include <linux/fs.h>
#include <linux/filter.h>
#include <linux/kernel.h>
#include <linux/btf_ids.h>

struct bpf_iter_seq_map_info {
	u32 map_id;
};

static void *bpf_map_seq_start(struct seq_file *seq, loff_t *pos)
{
	struct bpf_iter_seq_map_info *info = seq->private;
	struct bpf_map *map;

	map = bpf_map_get_curr_or_next(&info->map_id);
	if (!map)
		return NULL;

	if (*pos == 0)
		++*pos;
	return map;
}

static void *bpf_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct bpf_iter_seq_map_info *info = seq->private;

	++*pos;
	++info->map_id;
	bpf_map_put((struct bpf_map *)v);
	return bpf_map_get_curr_or_next(&info->map_id);
}

struct bpf_iter__bpf_map {
	__bpf_md_ptr(struct bpf_iter_meta *, meta);
	__bpf_md_ptr(struct bpf_map *, map);
};

DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta *meta, struct bpf_map *map)

static int __bpf_map_seq_show(struct seq_file *seq, void *v, bool in_stop)
{
	struct bpf_iter__bpf_map ctx;
	struct bpf_iter_meta meta;
	struct bpf_prog *prog;
	int ret = 0;

	ctx.meta = &meta;
	ctx.map = v;
	meta.seq = seq;
	prog = bpf_iter_get_info(&meta, in_stop);
	if (prog)
		ret = bpf_iter_run_prog(prog, &ctx);

	return ret;
}

static int bpf_map_seq_show(struct seq_file *seq, void *v)
{
	return __bpf_map_seq_show(seq, v, false);
}

static void bpf_map_seq_stop(struct seq_file *seq, void *v)
{
	if (!v)
		(void)__bpf_map_seq_show(seq, v, true);
	else
		bpf_map_put((struct bpf_map *)v);
}

static const struct seq_operations bpf_map_seq_ops = {
	.start	= bpf_map_seq_start,
	.next	= bpf_map_seq_next,
	.stop	= bpf_map_seq_stop,
	.show	= bpf_map_seq_show,
};

BTF_ID_LIST(btf_bpf_map_id)
BTF_ID(struct, bpf_map)

static const struct bpf_iter_seq_info bpf_map_seq_info = {
	.seq_ops		= &bpf_map_seq_ops,
	.init_seq_private	= NULL,
	.fini_seq_private	= NULL,
	.seq_priv_size		= sizeof(struct bpf_iter_seq_map_info),
};

static struct bpf_iter_reg bpf_map_reg_info = {
	.target			= "bpf_map",
	.ctx_arg_info_size	= 1,
	.ctx_arg_info		= {
		{ offsetof(struct bpf_iter__bpf_map, map),
		  PTR_TO_BTF_ID_OR_NULL },
	},
	.seq_info		= &bpf_map_seq_info,
};

static int bpf_iter_attach_map(struct bpf_prog *prog,
			       union bpf_iter_link_info *linfo,
			       struct bpf_iter_aux_info *aux)
{
	u32 key_acc_size, value_acc_size, key_size, value_size;
	struct bpf_map *map;
	bool is_percpu = false;
	int err = -EINVAL;

	if (!linfo->map.map_fd)
		return -EBADF;

	map = bpf_map_get_with_uref(linfo->map.map_fd);
	if (IS_ERR(map))
		return PTR_ERR(map);

	if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
	    map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
	    map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
		is_percpu = true;
	else if (map->map_type != BPF_MAP_TYPE_HASH &&
		 map->map_type != BPF_MAP_TYPE_LRU_HASH &&
		 map->map_type != BPF_MAP_TYPE_ARRAY)
		goto put_map;

	key_acc_size = prog->aux->max_rdonly_access;
	value_acc_size = prog->aux->max_rdwr_access;
	key_size = map->key_size;
	if (!is_percpu)
		value_size = map->value_size;
	else
		value_size = round_up(map->value_size, 8) * num_possible_cpus();

	if (key_acc_size > key_size || value_acc_size > value_size) {
		err = -EACCES;
		goto put_map;
	}

	aux->map = map;
	return 0;

put_map:
	bpf_map_put_with_uref(map);
	return err;
}

static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux)
{
	bpf_map_put_with_uref(aux->map);
}

DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta,
		     struct bpf_map *map, void *key, void *value)

static const struct bpf_iter_reg bpf_map_elem_reg_info = {
	.target			= "bpf_map_elem",
	.attach_target		= bpf_iter_attach_map,
	.detach_target		= bpf_iter_detach_map,
	.ctx_arg_info_size	= 2,
	.ctx_arg_info		= {
		{ offsetof(struct bpf_iter__bpf_map_elem, key),
		  PTR_TO_RDONLY_BUF_OR_NULL },
		{ offsetof(struct bpf_iter__bpf_map_elem, value),
		  PTR_TO_RDWR_BUF_OR_NULL },
	},
};

static int __init bpf_map_iter_init(void)
{
	int ret;

	bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id;
	ret = bpf_iter_reg_target(&bpf_map_reg_info);
	if (ret)
		return ret;

	return bpf_iter_reg_target(&bpf_map_elem_reg_info);
}

late_initcall(bpf_map_iter_init);
Commit	Line	Data
6086d29d YS	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/* Copyright (c) 2020 Facebook */
	3	#include <linux/bpf.h>
	4	#include <linux/fs.h>
	5	#include <linux/filter.h>
	6	#include <linux/kernel.h>
951cf368	7	#include <linux/btf_ids.h>
6086d29d YS	8
6086d29d YS	9	struct bpf_iter_seq_map_info {
3f9969f2	10	u32 map_id;
6086d29d YS	11	};
	12
	13	static void bpf_map_seq_start(struct seq_file seq, loff_t *pos)
	14	{
	15	struct bpf_iter_seq_map_info *info = seq->private;
	16	struct bpf_map *map;
	17
3f9969f2	18	map = bpf_map_get_curr_or_next(&info->map_id);
6086d29d YS	19	if (!map)
	20	return NULL;
	21
3f9969f2 YS	22	if (*pos == 0)
3f9969f2 YS	23	++*pos;
6086d29d YS	24	return map;
	25	}
	26
	27	static void bpf_map_seq_next(struct seq_file seq, void v, loff_t pos)
	28	{
	29	struct bpf_iter_seq_map_info *info = seq->private;
6086d29d YS	30
6086d29d YS	31	++*pos;
3f9969f2	32	++info->map_id;
6086d29d	33	bpf_map_put((struct bpf_map *)v);
3f9969f2	34	return bpf_map_get_curr_or_next(&info->map_id);
6086d29d YS	35	}
	36
	37	struct bpf_iter__bpf_map {
	38	__bpf_md_ptr(struct bpf_iter_meta *, meta);
	39	__bpf_md_ptr(struct bpf_map *, map);
	40	};
	41
	42	DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta meta, struct bpf_map map)
	43
	44	static int __bpf_map_seq_show(struct seq_file seq, void v, bool in_stop)
	45	{
	46	struct bpf_iter__bpf_map ctx;
	47	struct bpf_iter_meta meta;
	48	struct bpf_prog *prog;
	49	int ret = 0;
	50
	51	ctx.meta = &meta;
	52	ctx.map = v;
	53	meta.seq = seq;
	54	prog = bpf_iter_get_info(&meta, in_stop);
	55	if (prog)
	56	ret = bpf_iter_run_prog(prog, &ctx);
	57
	58	return ret;
	59	}
	60
	61	static int bpf_map_seq_show(struct seq_file seq, void v)
	62	{
	63	return __bpf_map_seq_show(seq, v, false);
	64	}
	65
	66	static void bpf_map_seq_stop(struct seq_file seq, void v)
	67	{
	68	if (!v)
	69	(void)__bpf_map_seq_show(seq, v, true);
	70	else
	71	bpf_map_put((struct bpf_map *)v);
	72	}
	73
	74	static const struct seq_operations bpf_map_seq_ops = {
	75	.start = bpf_map_seq_start,
	76	.next = bpf_map_seq_next,
	77	.stop = bpf_map_seq_stop,
	78	.show = bpf_map_seq_show,
	79	};
	80
951cf368 YS	81	BTF_ID_LIST(btf_bpf_map_id)
	82	BTF_ID(struct, bpf_map)
	83
14fc6bd6	84	static const struct bpf_iter_seq_info bpf_map_seq_info = {
15172a46 YS	85	.seq_ops = &bpf_map_seq_ops,
	86	.init_seq_private = NULL,
	87	.fini_seq_private = NULL,
	88	.seq_priv_size = sizeof(struct bpf_iter_seq_map_info),
14fc6bd6 YS	89	};
	90
	91	static struct bpf_iter_reg bpf_map_reg_info = {
	92	.target = "bpf_map",
3c32cc1b YS	93	.ctx_arg_info_size = 1,
	94	.ctx_arg_info = {
	95	{ offsetof(struct bpf_iter__bpf_map, map),
	96	PTR_TO_BTF_ID_OR_NULL },
	97	},
14fc6bd6	98	.seq_info = &bpf_map_seq_info,
15172a46 YS	99	};
15172a46 YS	100
5e7b3020 YS	101	static int bpf_iter_attach_map(struct bpf_prog *prog,
	102	union bpf_iter_link_info *linfo,
	103	struct bpf_iter_aux_info *aux)
a5cbe05a	104	{
d6c4503c	105	u32 key_acc_size, value_acc_size, key_size, value_size;
5e7b3020	106	struct bpf_map *map;
d6c4503c	107	bool is_percpu = false;
5e7b3020 YS	108	int err = -EINVAL;
	109
	110	if (!linfo->map.map_fd)
	111	return -EBADF;
	112
	113	map = bpf_map_get_with_uref(linfo->map.map_fd);
	114	if (IS_ERR(map))
	115	return PTR_ERR(map);
d6c4503c YS	116
d6c4503c YS	117	if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH \|\|
d3cc2ab5 YS	118	map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH \|\|
d3cc2ab5 YS	119	map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
d6c4503c YS	120	is_percpu = true;
d6c4503c YS	121	else if (map->map_type != BPF_MAP_TYPE_HASH &&
d3cc2ab5 YS	122	map->map_type != BPF_MAP_TYPE_LRU_HASH &&
d3cc2ab5 YS	123	map->map_type != BPF_MAP_TYPE_ARRAY)
5e7b3020	124	goto put_map;
d6c4503c YS	125
	126	key_acc_size = prog->aux->max_rdonly_access;
	127	value_acc_size = prog->aux->max_rdwr_access;
	128	key_size = map->key_size;
	129	if (!is_percpu)
	130	value_size = map->value_size;
	131	else
	132	value_size = round_up(map->value_size, 8) * num_possible_cpus();
	133
5e7b3020 YS	134	if (key_acc_size > key_size \|\| value_acc_size > value_size) {
	135	err = -EACCES;
	136	goto put_map;
	137	}
d6c4503c	138
5e7b3020	139	aux->map = map;
d6c4503c	140	return 0;
5e7b3020 YS	141
	142	put_map:
	143	bpf_map_put_with_uref(map);
	144	return err;
	145	}
	146
	147	static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux)
	148	{
	149	bpf_map_put_with_uref(aux->map);
a5cbe05a YS	150	}
	151
	152	DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta,
	153	struct bpf_map map, void key, void *value)
	154
	155	static const struct bpf_iter_reg bpf_map_elem_reg_info = {
	156	.target = "bpf_map_elem",
5e7b3020 YS	157	.attach_target = bpf_iter_attach_map,
5e7b3020 YS	158	.detach_target = bpf_iter_detach_map,
a5cbe05a YS	159	.ctx_arg_info_size = 2,
	160	.ctx_arg_info = {
	161	{ offsetof(struct bpf_iter__bpf_map_elem, key),
	162	PTR_TO_RDONLY_BUF_OR_NULL },
	163	{ offsetof(struct bpf_iter__bpf_map_elem, value),
	164	PTR_TO_RDWR_BUF_OR_NULL },
	165	},
	166	};
	167
6086d29d YS	168	static int __init bpf_map_iter_init(void)
6086d29d YS	169	{
a5cbe05a YS	170	int ret;
a5cbe05a YS	171
951cf368	172	bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id;
a5cbe05a YS	173	ret = bpf_iter_reg_target(&bpf_map_reg_info);
	174	if (ret)
	175	return ret;
	176
	177	return bpf_iter_reg_target(&bpf_map_elem_reg_info);
6086d29d YS	178	}
	179
	180	late_initcall(bpf_map_iter_init);