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1/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
2 * Copyright (c) 2016 Facebook
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 */
13
14#include <linux/bpf.h>
15
16#include "disasm.h"
17
18#define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
19static const char * const func_id_str[] = {
20 __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
21};
22#undef __BPF_FUNC_STR_FN
23
24static const char *__func_get_name(const struct bpf_insn_cbs *cbs,
25 const struct bpf_insn *insn,
26 char *buff, size_t len)
27{
28 BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);
29
30 if (insn->src_reg != BPF_PSEUDO_CALL &&
31 insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID &&
32 func_id_str[insn->imm])
33 return func_id_str[insn->imm];
34
35 if (cbs && cbs->cb_call)
36 return cbs->cb_call(cbs->private_data, insn);
37
38 if (insn->src_reg == BPF_PSEUDO_CALL)
39 snprintf(buff, len, "%+d", insn->imm);
40
41 return buff;
42}
43
44static const char *__func_imm_name(const struct bpf_insn_cbs *cbs,
45 const struct bpf_insn *insn,
46 u64 full_imm, char *buff, size_t len)
47{
48 if (cbs && cbs->cb_imm)
49 return cbs->cb_imm(cbs->private_data, insn, full_imm);
50
51 snprintf(buff, len, "0x%llx", (unsigned long long)full_imm);
52 return buff;
53}
54
55const char *func_id_name(int id)
56{
57 if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id])
58 return func_id_str[id];
59 else
60 return "unknown";
61}
62
63const char *const bpf_class_string[8] = {
64 [BPF_LD] = "ld",
65 [BPF_LDX] = "ldx",
66 [BPF_ST] = "st",
67 [BPF_STX] = "stx",
68 [BPF_ALU] = "alu",
69 [BPF_JMP] = "jmp",
70 [BPF_RET] = "BUG",
71 [BPF_ALU64] = "alu64",
72};
73
74const char *const bpf_alu_string[16] = {
75 [BPF_ADD >> 4] = "+=",
76 [BPF_SUB >> 4] = "-=",
77 [BPF_MUL >> 4] = "*=",
78 [BPF_DIV >> 4] = "/=",
79 [BPF_OR >> 4] = "|=",
80 [BPF_AND >> 4] = "&=",
81 [BPF_LSH >> 4] = "<<=",
82 [BPF_RSH >> 4] = ">>=",
83 [BPF_NEG >> 4] = "neg",
84 [BPF_MOD >> 4] = "%=",
85 [BPF_XOR >> 4] = "^=",
86 [BPF_MOV >> 4] = "=",
87 [BPF_ARSH >> 4] = "s>>=",
88 [BPF_END >> 4] = "endian",
89};
90
91static const char *const bpf_ldst_string[] = {
92 [BPF_W >> 3] = "u32",
93 [BPF_H >> 3] = "u16",
94 [BPF_B >> 3] = "u8",
95 [BPF_DW >> 3] = "u64",
96};
97
98static const char *const bpf_jmp_string[16] = {
99 [BPF_JA >> 4] = "jmp",
100 [BPF_JEQ >> 4] = "==",
101 [BPF_JGT >> 4] = ">",
102 [BPF_JLT >> 4] = "<",
103 [BPF_JGE >> 4] = ">=",
104 [BPF_JLE >> 4] = "<=",
105 [BPF_JSET >> 4] = "&",
106 [BPF_JNE >> 4] = "!=",
107 [BPF_JSGT >> 4] = "s>",
108 [BPF_JSLT >> 4] = "s<",
109 [BPF_JSGE >> 4] = "s>=",
110 [BPF_JSLE >> 4] = "s<=",
111 [BPF_CALL >> 4] = "call",
112 [BPF_EXIT >> 4] = "exit",
113};
114
115static void print_bpf_end_insn(bpf_insn_print_t verbose,
116 void *private_data,
117 const struct bpf_insn *insn)
118{
119 verbose(private_data, "(%02x) r%d = %s%d r%d\n",
120 insn->code, insn->dst_reg,
121 BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le",
122 insn->imm, insn->dst_reg);
123}
124
125void print_bpf_insn(const struct bpf_insn_cbs *cbs,
126 const struct bpf_insn *insn,
127 bool allow_ptr_leaks)
128{
129 const bpf_insn_print_t verbose = cbs->cb_print;
130 u8 class = BPF_CLASS(insn->code);
131
132 if (class == BPF_ALU || class == BPF_ALU64) {
133 if (BPF_OP(insn->code) == BPF_END) {
134 if (class == BPF_ALU64)
135 verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code);
136 else
137 print_bpf_end_insn(verbose, cbs->private_data, insn);
138 } else if (BPF_OP(insn->code) == BPF_NEG) {
139 verbose(cbs->private_data, "(%02x) r%d = %s-r%d\n",
140 insn->code, insn->dst_reg,
141 class == BPF_ALU ? "(u32) " : "",
142 insn->dst_reg);
143 } else if (BPF_SRC(insn->code) == BPF_X) {
144 verbose(cbs->private_data, "(%02x) %sr%d %s %sr%d\n",
145 insn->code, class == BPF_ALU ? "(u32) " : "",
146 insn->dst_reg,
147 bpf_alu_string[BPF_OP(insn->code) >> 4],
148 class == BPF_ALU ? "(u32) " : "",
149 insn->src_reg);
150 } else {
151 verbose(cbs->private_data, "(%02x) %sr%d %s %s%d\n",
152 insn->code, class == BPF_ALU ? "(u32) " : "",
153 insn->dst_reg,
154 bpf_alu_string[BPF_OP(insn->code) >> 4],
155 class == BPF_ALU ? "(u32) " : "",
156 insn->imm);
157 }
158 } else if (class == BPF_STX) {
159 if (BPF_MODE(insn->code) == BPF_MEM)
160 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n",
161 insn->code,
162 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
163 insn->dst_reg,
164 insn->off, insn->src_reg);
165 else if (BPF_MODE(insn->code) == BPF_XADD)
166 verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) += r%d\n",
167 insn->code,
168 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
169 insn->dst_reg, insn->off,
170 insn->src_reg);
171 else
172 verbose(cbs->private_data, "BUG_%02x\n", insn->code);
173 } else if (class == BPF_ST) {
174 if (BPF_MODE(insn->code) != BPF_MEM) {
175 verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
176 return;
177 }
178 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n",
179 insn->code,
180 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
181 insn->dst_reg,
182 insn->off, insn->imm);
183 } else if (class == BPF_LDX) {
184 if (BPF_MODE(insn->code) != BPF_MEM) {
185 verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
186 return;
187 }
188 verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n",
189 insn->code, insn->dst_reg,
190 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
191 insn->src_reg, insn->off);
192 } else if (class == BPF_LD) {
193 if (BPF_MODE(insn->code) == BPF_ABS) {
194 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n",
195 insn->code,
196 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
197 insn->imm);
198 } else if (BPF_MODE(insn->code) == BPF_IND) {
199 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
200 insn->code,
201 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
202 insn->src_reg, insn->imm);
203 } else if (BPF_MODE(insn->code) == BPF_IMM &&
204 BPF_SIZE(insn->code) == BPF_DW) {
205 /* At this point, we already made sure that the second
206 * part of the ldimm64 insn is accessible.
207 */
208 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
209 bool map_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD;
210 char tmp[64];
211
212 if (map_ptr && !allow_ptr_leaks)
213 imm = 0;
214
215 verbose(cbs->private_data, "(%02x) r%d = %s\n",
216 insn->code, insn->dst_reg,
217 __func_imm_name(cbs, insn, imm,
218 tmp, sizeof(tmp)));
219 } else {
220 verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
221 return;
222 }
223 } else if (class == BPF_JMP) {
224 u8 opcode = BPF_OP(insn->code);
225
226 if (opcode == BPF_CALL) {
227 char tmp[64];
228
229 if (insn->src_reg == BPF_PSEUDO_CALL) {
230 verbose(cbs->private_data, "(%02x) call pc%s\n",
231 insn->code,
232 __func_get_name(cbs, insn,
233 tmp, sizeof(tmp)));
234 } else {
235 strcpy(tmp, "unknown");
236 verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code,
237 __func_get_name(cbs, insn,
238 tmp, sizeof(tmp)),
239 insn->imm);
240 }
241 } else if (insn->code == (BPF_JMP | BPF_JA)) {
242 verbose(cbs->private_data, "(%02x) goto pc%+d\n",
243 insn->code, insn->off);
244 } else if (insn->code == (BPF_JMP | BPF_EXIT)) {
245 verbose(cbs->private_data, "(%02x) exit\n", insn->code);
246 } else if (BPF_SRC(insn->code) == BPF_X) {
247 verbose(cbs->private_data, "(%02x) if r%d %s r%d goto pc%+d\n",
248 insn->code, insn->dst_reg,
249 bpf_jmp_string[BPF_OP(insn->code) >> 4],
250 insn->src_reg, insn->off);
251 } else {
252 verbose(cbs->private_data, "(%02x) if r%d %s 0x%x goto pc%+d\n",
253 insn->code, insn->dst_reg,
254 bpf_jmp_string[BPF_OP(insn->code) >> 4],
255 insn->imm, insn->off);
256 }
257 } else {
258 verbose(cbs->private_data, "(%02x) %s\n",
259 insn->code, bpf_class_string[class]);
260 }
261}