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| 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 | + |
| 13 | +struct bpf_reg_state { |
| 14 | + enum bpf_reg_type type; |
| 15 | + union { |
| 16 | + /* valid when type == CONST_IMM | PTR_TO_STACK | UNKNOWN_VALUE */ |
| 17 | + s64 imm; |
| 18 | + |
| 19 | + /* valid when type == PTR_TO_PACKET* */ |
| 20 | + struct { |
| 21 | + u32 id; |
| 22 | + u16 off; |
| 23 | + u16 range; |
| 24 | + }; |
| 25 | + |
| 26 | + /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE | |
| 27 | + * PTR_TO_MAP_VALUE_OR_NULL |
| 28 | + */ |
| 29 | + struct bpf_map *map_ptr; |
| 30 | + }; |
| 31 | +}; |
| 32 | + |
| 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 */ |
| 37 | +}; |
| 38 | + |
| 39 | +#define BPF_REG_SIZE 8 /* size of eBPF register in bytes */ |
| 40 | + |
| 41 | +/* state of the program: |
| 42 | + * type of all registers and stack info |
| 43 | + */ |
| 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]; |
| 48 | +}; |
| 49 | + |
| 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; |
| 54 | +}; |
| 55 | + |
| 56 | +struct bpf_insn_aux_data { |
| 57 | + enum bpf_reg_type ptr_type; /* pointer type for load/store insns */ |
| 58 | +}; |
| 59 | + |
| 60 | +#define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */ |
| 61 | + |
| 62 | +/* single container for all structs |
| 63 | + * one verifier_env per bpf_check() call |
| 64 | + */ |
| 65 | +struct bpf_verifier_env { |
| 66 | + struct bpf_prog *prog; /* eBPF program being verified */ |
| 67 | + struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */ |
| 68 | + int stack_size; /* number of states to be processed */ |
| 69 | + struct bpf_verifier_state cur_state; /* current verifier state */ |
| 70 | + struct bpf_verifier_state_list **explored_states; /* search pruning optimization */ |
| 71 | + struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */ |
| 72 | + u32 used_map_cnt; /* number of used maps */ |
| 73 | + u32 id_gen; /* used to generate unique reg IDs */ |
| 74 | + bool allow_ptr_leaks; |
| 75 | + bool seen_direct_write; |
| 76 | + struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */ |
| 77 | +}; |
| 78 | + |
| 79 | +#endif /* _LINUX_BPF_VERIFIER_H */ |
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