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 struct bpf_reg_state {
14 enum bpf_reg_type type;
16 /* valid when type == CONST_IMM | PTR_TO_STACK | UNKNOWN_VALUE */
19 /* valid when type == PTR_TO_PACKET* */
26 /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE |
27 * PTR_TO_MAP_VALUE_OR_NULL
29 struct bpf_map *map_ptr;
33 enum bpf_stack_slot_type {
34 STACK_INVALID, /* nothing was stored in this stack slot */
35 STACK_SPILL, /* register spilled into stack */
36 STACK_MISC /* BPF program wrote some data into this slot */
39 #define BPF_REG_SIZE 8 /* size of eBPF register in bytes */
41 /* state of the program:
42 * type of all registers and stack info
44 struct bpf_verifier_state {
45 struct bpf_reg_state regs[MAX_BPF_REG];
46 u8 stack_slot_type[MAX_BPF_STACK];
47 struct bpf_reg_state spilled_regs[MAX_BPF_STACK / BPF_REG_SIZE];
50 /* linked list of verifier states used to prune search */
51 struct bpf_verifier_state_list {
52 struct bpf_verifier_state state;
53 struct bpf_verifier_state_list *next;
56 struct bpf_insn_aux_data {
57 enum bpf_reg_type ptr_type; /* pointer type for load/store insns */
60 #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */
62 struct bpf_verifier_env;
63 struct bpf_ext_analyzer_ops {
64 int (*insn_hook)(struct bpf_verifier_env *env,
65 int insn_idx, int prev_insn_idx);
68 /* single container for all structs
69 * one verifier_env per bpf_check() call
71 struct bpf_verifier_env {
72 struct bpf_prog *prog; /* eBPF program being verified */
73 struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */
74 int stack_size; /* number of states to be processed */
75 struct bpf_verifier_state cur_state; /* current verifier state */
76 struct bpf_verifier_state_list **explored_states; /* search pruning optimization */
77 const struct bpf_ext_analyzer_ops *analyzer_ops; /* external analyzer ops */
78 void *analyzer_priv; /* pointer to external analyzer's private data */
79 struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */
80 u32 used_map_cnt; /* number of used maps */
81 u32 id_gen; /* used to generate unique reg IDs */
83 bool seen_direct_write;
84 struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */
87 int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops,
90 #endif /* _LINUX_BPF_VERIFIER_H */