Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 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 */ |
Edward Cree | f1174f7 | 2017-08-07 15:26:19 +0100 | [diff] [blame^] | 12 | #include <linux/tnum.h> |
Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 13 | |
Josef Bacik | 4846113 | 2016-09-28 10:54:32 -0400 | [diff] [blame] | 14 | /* Just some arbitrary values so we can safely do math without overflowing and |
| 15 | * are obviously wrong for any sort of memory access. |
| 16 | */ |
| 17 | #define BPF_REGISTER_MAX_RANGE (1024 * 1024 * 1024) |
Josef Bacik | f23cc64 | 2016-11-14 15:45:36 -0500 | [diff] [blame] | 18 | #define BPF_REGISTER_MIN_RANGE -1 |
Josef Bacik | 4846113 | 2016-09-28 10:54:32 -0400 | [diff] [blame] | 19 | |
Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 20 | struct bpf_reg_state { |
| 21 | enum bpf_reg_type type; |
| 22 | union { |
Edward Cree | f1174f7 | 2017-08-07 15:26:19 +0100 | [diff] [blame^] | 23 | /* valid when type == PTR_TO_PACKET */ |
| 24 | u16 range; |
Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 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 | }; |
Edward Cree | f1174f7 | 2017-08-07 15:26:19 +0100 | [diff] [blame^] | 31 | /* Fixed part of pointer offset, pointer types only */ |
| 32 | s32 off; |
| 33 | /* For PTR_TO_PACKET, used to find other pointers with the same variable |
| 34 | * offset, so they can share range knowledge. |
| 35 | * For PTR_TO_MAP_VALUE_OR_NULL this is used to share which map value we |
| 36 | * came from, when one is tested for != NULL. |
| 37 | */ |
Alexei Starovoitov | d2a4dd3 | 2016-12-07 10:57:59 -0800 | [diff] [blame] | 38 | u32 id; |
Edward Cree | f1174f7 | 2017-08-07 15:26:19 +0100 | [diff] [blame^] | 39 | /* These three fields must be last. See states_equal() */ |
| 40 | /* For scalar types (SCALAR_VALUE), this represents our knowledge of |
| 41 | * the actual value. |
| 42 | * For pointer types, this represents the variable part of the offset |
| 43 | * from the pointed-to object, and is shared with all bpf_reg_states |
| 44 | * with the same id as us. |
| 45 | */ |
| 46 | struct tnum var_off; |
Alexei Starovoitov | d2a4dd3 | 2016-12-07 10:57:59 -0800 | [diff] [blame] | 47 | /* Used to determine if any memory access using this register will |
Edward Cree | f1174f7 | 2017-08-07 15:26:19 +0100 | [diff] [blame^] | 48 | * result in a bad access. |
| 49 | * These refer to the same value as var_off, not necessarily the actual |
| 50 | * contents of the register. |
Alexei Starovoitov | d2a4dd3 | 2016-12-07 10:57:59 -0800 | [diff] [blame] | 51 | */ |
| 52 | s64 min_value; |
| 53 | u64 max_value; |
Daniel Borkmann | 4cabc5b | 2017-07-21 00:00:21 +0200 | [diff] [blame] | 54 | bool value_from_signed; |
Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 55 | }; |
| 56 | |
| 57 | enum bpf_stack_slot_type { |
| 58 | STACK_INVALID, /* nothing was stored in this stack slot */ |
| 59 | STACK_SPILL, /* register spilled into stack */ |
| 60 | STACK_MISC /* BPF program wrote some data into this slot */ |
| 61 | }; |
| 62 | |
| 63 | #define BPF_REG_SIZE 8 /* size of eBPF register in bytes */ |
| 64 | |
| 65 | /* state of the program: |
| 66 | * type of all registers and stack info |
| 67 | */ |
| 68 | struct bpf_verifier_state { |
| 69 | struct bpf_reg_state regs[MAX_BPF_REG]; |
| 70 | u8 stack_slot_type[MAX_BPF_STACK]; |
| 71 | struct bpf_reg_state spilled_regs[MAX_BPF_STACK / BPF_REG_SIZE]; |
| 72 | }; |
| 73 | |
| 74 | /* linked list of verifier states used to prune search */ |
| 75 | struct bpf_verifier_state_list { |
| 76 | struct bpf_verifier_state state; |
| 77 | struct bpf_verifier_state_list *next; |
| 78 | }; |
| 79 | |
| 80 | struct bpf_insn_aux_data { |
Alexei Starovoitov | 81ed18a | 2017-03-15 18:26:42 -0700 | [diff] [blame] | 81 | union { |
| 82 | enum bpf_reg_type ptr_type; /* pointer type for load/store insns */ |
| 83 | struct bpf_map *map_ptr; /* pointer for call insn into lookup_elem */ |
| 84 | }; |
Yonghong Song | 2399463 | 2017-06-22 15:07:39 -0700 | [diff] [blame] | 85 | int ctx_field_size; /* the ctx field size for load insn, maybe 0 */ |
| 86 | int converted_op_size; /* the valid value width after perceived conversion */ |
Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 87 | }; |
| 88 | |
| 89 | #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */ |
| 90 | |
Jakub Kicinski | 13a27df | 2016-09-21 11:43:58 +0100 | [diff] [blame] | 91 | struct bpf_verifier_env; |
| 92 | struct bpf_ext_analyzer_ops { |
| 93 | int (*insn_hook)(struct bpf_verifier_env *env, |
| 94 | int insn_idx, int prev_insn_idx); |
| 95 | }; |
| 96 | |
Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 97 | /* single container for all structs |
| 98 | * one verifier_env per bpf_check() call |
| 99 | */ |
| 100 | struct bpf_verifier_env { |
| 101 | struct bpf_prog *prog; /* eBPF program being verified */ |
| 102 | struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */ |
| 103 | int stack_size; /* number of states to be processed */ |
David S. Miller | e07b98d | 2017-05-10 11:38:07 -0700 | [diff] [blame] | 104 | bool strict_alignment; /* perform strict pointer alignment checks */ |
Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 105 | struct bpf_verifier_state cur_state; /* current verifier state */ |
| 106 | struct bpf_verifier_state_list **explored_states; /* search pruning optimization */ |
Jakub Kicinski | 13a27df | 2016-09-21 11:43:58 +0100 | [diff] [blame] | 107 | const struct bpf_ext_analyzer_ops *analyzer_ops; /* external analyzer ops */ |
| 108 | void *analyzer_priv; /* pointer to external analyzer's private data */ |
Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 109 | struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */ |
| 110 | u32 used_map_cnt; /* number of used maps */ |
| 111 | u32 id_gen; /* used to generate unique reg IDs */ |
| 112 | bool allow_ptr_leaks; |
| 113 | bool seen_direct_write; |
Josef Bacik | 4846113 | 2016-09-28 10:54:32 -0400 | [diff] [blame] | 114 | bool varlen_map_value_access; |
Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 115 | struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */ |
| 116 | }; |
| 117 | |
Jakub Kicinski | 13a27df | 2016-09-21 11:43:58 +0100 | [diff] [blame] | 118 | int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops, |
| 119 | void *priv); |
| 120 | |
Jakub Kicinski | 58e2af8b | 2016-09-21 11:43:57 +0100 | [diff] [blame] | 121 | #endif /* _LINUX_BPF_VERIFIER_H */ |