[mirror_ubuntu-artful-kernel.git] / include / linux / bpf_verifier.h

/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */
#ifndef _LINUX_BPF_VERIFIER_H
#define _LINUX_BPF_VERIFIER_H 1

#include <linux/bpf.h> /* for enum bpf_reg_type */
#include <linux/filter.h> /* for MAX_BPF_STACK */

 /* Just some arbitrary values so we can safely do math without overflowing and
  * are obviously wrong for any sort of memory access.
  */
#define BPF_REGISTER_MAX_RANGE (1024 * 1024 * 1024)
#define BPF_REGISTER_MIN_RANGE -1

struct bpf_reg_state {
	enum bpf_reg_type type;
	union {
		/* valid when type == CONST_IMM | PTR_TO_STACK | UNKNOWN_VALUE */
		s64 imm;

		/* valid when type == PTR_TO_PACKET* */
		struct {
			u16 off;
			u16 range;
		};

		/* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE |
		 *   PTR_TO_MAP_VALUE_OR_NULL
		 */
		struct bpf_map *map_ptr;
	};
	u32 id;
	/* Used to determine if any memory access using this register will
	 * result in a bad access. These two fields must be last.
	 * See states_equal()
	 */
	s64 min_value;
	u64 max_value;
	u32 min_align;
	u32 aux_off;
	u32 aux_off_align;
	bool value_from_signed;
};

enum bpf_stack_slot_type {
	STACK_INVALID,    /* nothing was stored in this stack slot */
	STACK_SPILL,      /* register spilled into stack */
	STACK_MISC	  /* BPF program wrote some data into this slot */
};

#define BPF_REG_SIZE 8	/* size of eBPF register in bytes */

/* state of the program:
 * type of all registers and stack info
 */
struct bpf_verifier_state {
	struct bpf_reg_state regs[MAX_BPF_REG];
	u8 stack_slot_type[MAX_BPF_STACK];
	struct bpf_reg_state spilled_regs[MAX_BPF_STACK / BPF_REG_SIZE];
};

/* linked list of verifier states used to prune search */
struct bpf_verifier_state_list {
	struct bpf_verifier_state state;
	struct bpf_verifier_state_list *next;
};

struct bpf_insn_aux_data {
	union {
		enum bpf_reg_type ptr_type;	/* pointer type for load/store insns */
		struct bpf_map *map_ptr;	/* pointer for call insn into lookup_elem */
	};
	int ctx_field_size; /* the ctx field size for load insn, maybe 0 */
	int converted_op_size; /* the valid value width after perceived conversion */
};

#define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */

struct bpf_verifier_env;
struct bpf_ext_analyzer_ops {
	int (*insn_hook)(struct bpf_verifier_env *env,
			 int insn_idx, int prev_insn_idx);
};

/* single container for all structs
 * one verifier_env per bpf_check() call
 */
struct bpf_verifier_env {
	struct bpf_prog *prog;		/* eBPF program being verified */
	struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */
	int stack_size;			/* number of states to be processed */
	bool strict_alignment;		/* perform strict pointer alignment checks */
	struct bpf_verifier_state cur_state; /* current verifier state */
	struct bpf_verifier_state_list **explored_states; /* search pruning optimization */
	const struct bpf_ext_analyzer_ops *analyzer_ops; /* external analyzer ops */
	void *analyzer_priv; /* pointer to external analyzer's private data */
	struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */
	u32 used_map_cnt;		/* number of used maps */
	u32 id_gen;			/* used to generate unique reg IDs */
	bool allow_ptr_leaks;
	bool seen_direct_write;
	bool varlen_map_value_access;
	struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */
};

int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops,
		 void *priv);

#endif /* _LINUX_BPF_VERIFIER_H */
Commit	Line	Data
58e2af8b JK	1	/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
	2	*
	3	* This program is free software; you can redistribute it and/or
	4	* modify it under the terms of version 2 of the GNU General Public
	5	* License as published by the Free Software Foundation.
	6	*/
	7	#ifndef _LINUX_BPF_VERIFIER_H
	8	#define _LINUX_BPF_VERIFIER_H 1
	9
	10	#include <linux/bpf.h> /* for enum bpf_reg_type */
	11	#include <linux/filter.h> /* for MAX_BPF_STACK */
	12
48461135 JB	13	/* Just some arbitrary values so we can safely do math without overflowing and
	14	* are obviously wrong for any sort of memory access.
	15	*/
	16	#define BPF_REGISTER_MAX_RANGE (1024 * 1024 * 1024)
f23cc643	17	#define BPF_REGISTER_MIN_RANGE -1
48461135	18
58e2af8b JK	19	struct bpf_reg_state {
	20	enum bpf_reg_type type;
	21	union {
	22	/* valid when type == CONST_IMM \| PTR_TO_STACK \| UNKNOWN_VALUE */
	23	s64 imm;
	24
	25	/* valid when type == PTR_TO_PACKET* */
	26	struct {
58e2af8b JK	27	u16 off;
	28	u16 range;
	29	};
	30
	31	/* valid when type == CONST_PTR_TO_MAP \| PTR_TO_MAP_VALUE \|
	32	* PTR_TO_MAP_VALUE_OR_NULL
	33	*/
	34	struct bpf_map *map_ptr;
	35	};
d2a4dd37 AS	36	u32 id;
	37	/* Used to determine if any memory access using this register will
	38	* result in a bad access. These two fields must be last.
	39	* See states_equal()
	40	*/
	41	s64 min_value;
	42	u64 max_value;
d1174416 DM	43	u32 min_align;
	44	u32 aux_off;
	45	u32 aux_off_align;
4cabc5b1	46	bool value_from_signed;
58e2af8b JK	47	};
	48
	49	enum bpf_stack_slot_type {
	50	STACK_INVALID, /* nothing was stored in this stack slot */
	51	STACK_SPILL, /* register spilled into stack */
	52	STACK_MISC /* BPF program wrote some data into this slot */
	53	};
	54
	55	#define BPF_REG_SIZE 8 /* size of eBPF register in bytes */
	56
	57	/* state of the program:
	58	* type of all registers and stack info
	59	*/
	60	struct bpf_verifier_state {
	61	struct bpf_reg_state regs[MAX_BPF_REG];
	62	u8 stack_slot_type[MAX_BPF_STACK];
	63	struct bpf_reg_state spilled_regs[MAX_BPF_STACK / BPF_REG_SIZE];
	64	};
	65
	66	/* linked list of verifier states used to prune search */
	67	struct bpf_verifier_state_list {
	68	struct bpf_verifier_state state;
	69	struct bpf_verifier_state_list *next;
	70	};
	71
	72	struct bpf_insn_aux_data {
81ed18ab AS	73	union {
	74	enum bpf_reg_type ptr_type; /* pointer type for load/store insns */
	75	struct bpf_map map_ptr; / pointer for call insn into lookup_elem */
	76	};
23994631 YS	77	int ctx_field_size; /* the ctx field size for load insn, maybe 0 */
23994631 YS	78	int converted_op_size; /* the valid value width after perceived conversion */
58e2af8b JK	79	};
	80
	81	#define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */
	82
13a27dfc JK	83	struct bpf_verifier_env;
	84	struct bpf_ext_analyzer_ops {
	85	int (insn_hook)(struct bpf_verifier_env env,
	86	int insn_idx, int prev_insn_idx);
	87	};
	88
58e2af8b JK	89	/* single container for all structs
	90	* one verifier_env per bpf_check() call
	91	*/
	92	struct bpf_verifier_env {
	93	struct bpf_prog prog; / eBPF program being verified */
	94	struct bpf_verifier_stack_elem head; / stack of verifier states to be processed */
	95	int stack_size; /* number of states to be processed */
e07b98d9	96	bool strict_alignment; /* perform strict pointer alignment checks */
58e2af8b JK	97	struct bpf_verifier_state cur_state; /* current verifier state */
58e2af8b JK	98	struct bpf_verifier_state_list *explored_states; / search pruning optimization */
13a27dfc JK	99	const struct bpf_ext_analyzer_ops analyzer_ops; / external analyzer ops */
13a27dfc JK	100	void analyzer_priv; / pointer to external analyzer's private data */
58e2af8b JK	101	struct bpf_map used_maps[MAX_USED_MAPS]; / array of map's used by eBPF program */
	102	u32 used_map_cnt; /* number of used maps */
	103	u32 id_gen; /* used to generate unique reg IDs */
	104	bool allow_ptr_leaks;
	105	bool seen_direct_write;
48461135	106	bool varlen_map_value_access;
58e2af8b JK	107	struct bpf_insn_aux_data insn_aux_data; / array of per-insn state */
	108	};
	109
13a27dfc JK	110	int bpf_analyzer(struct bpf_prog prog, const struct bpf_ext_analyzer_ops ops,
	111	void *priv);
	112
58e2af8b	113	#endif /* _LINUX_BPF_VERIFIER_H */