1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
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.
7 #ifndef _LINUX_BPF_VERIFIER_H
8 #define _LINUX_BPF_VERIFIER_H 1
10 #include <linux/bpf.h> /* for enum bpf_reg_type */
11 #include <linux/filter.h> /* for MAX_BPF_STACK */
13 /* Just some arbitrary values so we can safely do math without overflowing and
14 * are obviously wrong for any sort of memory access.
16 #define BPF_REGISTER_MAX_RANGE (1024 * 1024 * 1024)
17 #define BPF_REGISTER_MIN_RANGE -(1024 * 1024 * 1024)
19 struct bpf_reg_state
{
20 enum bpf_reg_type type
;
22 * Used to determine if any memory access using this register will
23 * result in a bad access.
25 u64 min_value
, max_value
;
27 /* valid when type == CONST_IMM | PTR_TO_STACK | UNKNOWN_VALUE */
30 /* valid when type == PTR_TO_PACKET* */
37 /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE |
38 * PTR_TO_MAP_VALUE_OR_NULL
40 struct bpf_map
*map_ptr
;
44 enum bpf_stack_slot_type
{
45 STACK_INVALID
, /* nothing was stored in this stack slot */
46 STACK_SPILL
, /* register spilled into stack */
47 STACK_MISC
/* BPF program wrote some data into this slot */
50 #define BPF_REG_SIZE 8 /* size of eBPF register in bytes */
52 /* state of the program:
53 * type of all registers and stack info
55 struct bpf_verifier_state
{
56 struct bpf_reg_state regs
[MAX_BPF_REG
];
57 u8 stack_slot_type
[MAX_BPF_STACK
];
58 struct bpf_reg_state spilled_regs
[MAX_BPF_STACK
/ BPF_REG_SIZE
];
61 /* linked list of verifier states used to prune search */
62 struct bpf_verifier_state_list
{
63 struct bpf_verifier_state state
;
64 struct bpf_verifier_state_list
*next
;
67 struct bpf_insn_aux_data
{
68 enum bpf_reg_type ptr_type
; /* pointer type for load/store insns */
71 #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */
73 struct bpf_verifier_env
;
74 struct bpf_ext_analyzer_ops
{
75 int (*insn_hook
)(struct bpf_verifier_env
*env
,
76 int insn_idx
, int prev_insn_idx
);
79 /* single container for all structs
80 * one verifier_env per bpf_check() call
82 struct bpf_verifier_env
{
83 struct bpf_prog
*prog
; /* eBPF program being verified */
84 struct bpf_verifier_stack_elem
*head
; /* stack of verifier states to be processed */
85 int stack_size
; /* number of states to be processed */
86 struct bpf_verifier_state cur_state
; /* current verifier state */
87 struct bpf_verifier_state_list
**explored_states
; /* search pruning optimization */
88 const struct bpf_ext_analyzer_ops
*analyzer_ops
; /* external analyzer ops */
89 void *analyzer_priv
; /* pointer to external analyzer's private data */
90 struct bpf_map
*used_maps
[MAX_USED_MAPS
]; /* array of map's used by eBPF program */
91 u32 used_map_cnt
; /* number of used maps */
92 u32 id_gen
; /* used to generate unique reg IDs */
94 bool seen_direct_write
;
95 bool varlen_map_value_access
;
96 struct bpf_insn_aux_data
*insn_aux_data
; /* array of per-insn state */
99 int bpf_analyzer(struct bpf_prog
*prog
, const struct bpf_ext_analyzer_ops
*ops
,
102 #endif /* _LINUX_BPF_VERIFIER_H */