1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * Copyright (c) 2016 Facebook
4 */
5
6#include <linux/bpf.h>
7
8#include "disasm.h"
9
10#define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
11static const char * const func_id_str[] = {
12 __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
13};
14#undef __BPF_FUNC_STR_FN
15
16static const char *__func_get_name(const struct bpf_insn_cbs *cbs,
17 const struct bpf_insn *insn,
18 char *buff, size_t len)
19{
20 BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);
21
22 if (!insn->src_reg &&
23 insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID &&
24 func_id_str[insn->imm])
25 return func_id_str[insn->imm];
26
27 if (cbs && cbs->cb_call) {
28 const char *res;
29
30 res = cbs->cb_call(cbs->private_data, insn);
31 if (res)
32 return res;
33 }
34
35 if (insn->src_reg == BPF_PSEUDO_CALL)
36 snprintf(buf: buff, size: len, fmt: "%+d", insn->imm);
37 else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL)
38 snprintf(buf: buff, size: len, fmt: "kernel-function");
39
40 return buff;
41}
42
43static const char *__func_imm_name(const struct bpf_insn_cbs *cbs,
44 const struct bpf_insn *insn,
45 u64 full_imm, char *buff, size_t len)
46{
47 if (cbs && cbs->cb_imm)
48 return cbs->cb_imm(cbs->private_data, insn, full_imm);
49
50 snprintf(buf: buff, size: len, fmt: "0x%llx", (unsigned long long)full_imm);
51 return buff;
52}
53
54const char *func_id_name(int id)
55{
56 if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id])
57 return func_id_str[id];
58 else
59 return "unknown";
60}
61
62const char *const bpf_class_string[8] = {
63 [BPF_LD] = "ld",
64 [BPF_LDX] = "ldx",
65 [BPF_ST] = "st",
66 [BPF_STX] = "stx",
67 [BPF_ALU] = "alu",
68 [BPF_JMP] = "jmp",
69 [BPF_JMP32] = "jmp32",
70 [BPF_ALU64] = "alu64",
71};
72
73const char *const bpf_alu_string[16] = {
74 [BPF_ADD >> 4] = "+=",
75 [BPF_SUB >> 4] = "-=",
76 [BPF_MUL >> 4] = "*=",
77 [BPF_DIV >> 4] = "/=",
78 [BPF_OR >> 4] = "|=",
79 [BPF_AND >> 4] = "&=",
80 [BPF_LSH >> 4] = "<<=",
81 [BPF_RSH >> 4] = ">>=",
82 [BPF_NEG >> 4] = "neg",
83 [BPF_MOD >> 4] = "%=",
84 [BPF_XOR >> 4] = "^=",
85 [BPF_MOV >> 4] = "=",
86 [BPF_ARSH >> 4] = "s>>=",
87 [BPF_END >> 4] = "endian",
88};
89
90static const char *const bpf_alu_sign_string[16] = {
91 [BPF_DIV >> 4] = "s/=",
92 [BPF_MOD >> 4] = "s%=",
93};
94
95static const char *const bpf_movsx_string[4] = {
96 [0] = "(s8)",
97 [1] = "(s16)",
98 [3] = "(s32)",
99};
100
101static const char *const bpf_atomic_alu_string[16] = {
102 [BPF_ADD >> 4] = "add",
103 [BPF_AND >> 4] = "and",
104 [BPF_OR >> 4] = "or",
105 [BPF_XOR >> 4] = "xor",
106};
107
108static const char *const bpf_ldst_string[] = {
109 [BPF_W >> 3] = "u32",
110 [BPF_H >> 3] = "u16",
111 [BPF_B >> 3] = "u8",
112 [BPF_DW >> 3] = "u64",
113};
114
115static const char *const bpf_ldsx_string[] = {
116 [BPF_W >> 3] = "s32",
117 [BPF_H >> 3] = "s16",
118 [BPF_B >> 3] = "s8",
119};
120
121static const char *const bpf_jmp_string[16] = {
122 [BPF_JA >> 4] = "jmp",
123 [BPF_JEQ >> 4] = "==",
124 [BPF_JGT >> 4] = ">",
125 [BPF_JLT >> 4] = "<",
126 [BPF_JGE >> 4] = ">=",
127 [BPF_JLE >> 4] = "<=",
128 [BPF_JSET >> 4] = "&",
129 [BPF_JNE >> 4] = "!=",
130 [BPF_JSGT >> 4] = "s>",
131 [BPF_JSLT >> 4] = "s<",
132 [BPF_JSGE >> 4] = "s>=",
133 [BPF_JSLE >> 4] = "s<=",
134 [BPF_CALL >> 4] = "call",
135 [BPF_EXIT >> 4] = "exit",
136};
137
138static void print_bpf_end_insn(bpf_insn_print_t verbose,
139 void *private_data,
140 const struct bpf_insn *insn)
141{
142 verbose(private_data, "(%02x) r%d = %s%d r%d\n",
143 insn->code, insn->dst_reg,
144 BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le",
145 insn->imm, insn->dst_reg);
146}
147
148static void print_bpf_bswap_insn(bpf_insn_print_t verbose,
149 void *private_data,
150 const struct bpf_insn *insn)
151{
152 verbose(private_data, "(%02x) r%d = bswap%d r%d\n",
153 insn->code, insn->dst_reg,
154 insn->imm, insn->dst_reg);
155}
156
157static bool is_sdiv_smod(const struct bpf_insn *insn)
158{
159 return (BPF_OP(insn->code) == BPF_DIV || BPF_OP(insn->code) == BPF_MOD) &&
160 insn->off == 1;
161}
162
163static bool is_movsx(const struct bpf_insn *insn)
164{
165 return BPF_OP(insn->code) == BPF_MOV &&
166 (insn->off == 8 || insn->off == 16 || insn->off == 32);
167}
168
169static bool is_addr_space_cast(const struct bpf_insn *insn)
170{
171 return insn->code == (BPF_ALU64 | BPF_MOV | BPF_X) &&
172 insn->off == BPF_ADDR_SPACE_CAST;
173}
174
175void print_bpf_insn(const struct bpf_insn_cbs *cbs,
176 const struct bpf_insn *insn,
177 bool allow_ptr_leaks)
178{
179 const bpf_insn_print_t verbose = cbs->cb_print;
180 u8 class = BPF_CLASS(insn->code);
181
182 if (class == BPF_ALU || class == BPF_ALU64) {
183 if (BPF_OP(insn->code) == BPF_END) {
184 if (class == BPF_ALU64)
185 print_bpf_bswap_insn(verbose, private_data: cbs->private_data, insn);
186 else
187 print_bpf_end_insn(verbose, private_data: cbs->private_data, insn);
188 } else if (BPF_OP(insn->code) == BPF_NEG) {
189 verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n",
190 insn->code, class == BPF_ALU ? 'w' : 'r',
191 insn->dst_reg, class == BPF_ALU ? 'w' : 'r',
192 insn->dst_reg);
193 } else if (is_addr_space_cast(insn)) {
194 verbose(cbs->private_data, "(%02x) r%d = addr_space_cast(r%d, %d, %d)\n",
195 insn->code, insn->dst_reg,
196 insn->src_reg, ((u32)insn->imm) >> 16, (u16)insn->imm);
197 } else if (BPF_SRC(insn->code) == BPF_X) {
198 verbose(cbs->private_data, "(%02x) %c%d %s %s%c%d\n",
199 insn->code, class == BPF_ALU ? 'w' : 'r',
200 insn->dst_reg,
201 is_sdiv_smod(insn) ? bpf_alu_sign_string[BPF_OP(insn->code) >> 4]
202 : bpf_alu_string[BPF_OP(insn->code) >> 4],
203 is_movsx(insn) ? bpf_movsx_string[(insn->off >> 3) - 1] : "",
204 class == BPF_ALU ? 'w' : 'r',
205 insn->src_reg);
206 } else {
207 verbose(cbs->private_data, "(%02x) %c%d %s %d\n",
208 insn->code, class == BPF_ALU ? 'w' : 'r',
209 insn->dst_reg,
210 is_sdiv_smod(insn) ? bpf_alu_sign_string[BPF_OP(insn->code) >> 4]
211 : bpf_alu_string[BPF_OP(insn->code) >> 4],
212 insn->imm);
213 }
214 } else if (class == BPF_STX) {
215 if (BPF_MODE(insn->code) == BPF_MEM)
216 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n",
217 insn->code,
218 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
219 insn->dst_reg,
220 insn->off, insn->src_reg);
221 else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
222 (insn->imm == BPF_ADD || insn->imm == BPF_AND ||
223 insn->imm == BPF_OR || insn->imm == BPF_XOR)) {
224 verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) %s r%d\n",
225 insn->code,
226 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
227 insn->dst_reg, insn->off,
228 bpf_alu_string[BPF_OP(insn->imm) >> 4],
229 insn->src_reg);
230 } else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
231 (insn->imm == (BPF_ADD | BPF_FETCH) ||
232 insn->imm == (BPF_AND | BPF_FETCH) ||
233 insn->imm == (BPF_OR | BPF_FETCH) ||
234 insn->imm == (BPF_XOR | BPF_FETCH))) {
235 verbose(cbs->private_data, "(%02x) r%d = atomic%s_fetch_%s((%s *)(r%d %+d), r%d)\n",
236 insn->code, insn->src_reg,
237 BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
238 bpf_atomic_alu_string[BPF_OP(insn->imm) >> 4],
239 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
240 insn->dst_reg, insn->off, insn->src_reg);
241 } else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
242 insn->imm == BPF_CMPXCHG) {
243 verbose(cbs->private_data, "(%02x) r0 = atomic%s_cmpxchg((%s *)(r%d %+d), r0, r%d)\n",
244 insn->code,
245 BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
246 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
247 insn->dst_reg, insn->off,
248 insn->src_reg);
249 } else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
250 insn->imm == BPF_XCHG) {
251 verbose(cbs->private_data, "(%02x) r%d = atomic%s_xchg((%s *)(r%d %+d), r%d)\n",
252 insn->code, insn->src_reg,
253 BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
254 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
255 insn->dst_reg, insn->off, insn->src_reg);
256 } else {
257 verbose(cbs->private_data, "BUG_%02x\n", insn->code);
258 }
259 } else if (class == BPF_ST) {
260 if (BPF_MODE(insn->code) == BPF_MEM) {
261 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n",
262 insn->code,
263 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
264 insn->dst_reg,
265 insn->off, insn->imm);
266 } else if (BPF_MODE(insn->code) == 0xc0 /* BPF_NOSPEC, no UAPI */) {
267 verbose(cbs->private_data, "(%02x) nospec\n", insn->code);
268 } else {
269 verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
270 }
271 } else if (class == BPF_LDX) {
272 if (BPF_MODE(insn->code) != BPF_MEM && BPF_MODE(insn->code) != BPF_MEMSX) {
273 verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
274 return;
275 }
276 verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n",
277 insn->code, insn->dst_reg,
278 BPF_MODE(insn->code) == BPF_MEM ?
279 bpf_ldst_string[BPF_SIZE(insn->code) >> 3] :
280 bpf_ldsx_string[BPF_SIZE(insn->code) >> 3],
281 insn->src_reg, insn->off);
282 } else if (class == BPF_LD) {
283 if (BPF_MODE(insn->code) == BPF_ABS) {
284 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n",
285 insn->code,
286 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
287 insn->imm);
288 } else if (BPF_MODE(insn->code) == BPF_IND) {
289 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
290 insn->code,
291 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
292 insn->src_reg, insn->imm);
293 } else if (BPF_MODE(insn->code) == BPF_IMM &&
294 BPF_SIZE(insn->code) == BPF_DW) {
295 /* At this point, we already made sure that the second
296 * part of the ldimm64 insn is accessible.
297 */
298 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
299 bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD ||
300 insn->src_reg == BPF_PSEUDO_MAP_VALUE;
301 char tmp[64];
302
303 if (is_ptr && !allow_ptr_leaks)
304 imm = 0;
305
306 verbose(cbs->private_data, "(%02x) r%d = %s\n",
307 insn->code, insn->dst_reg,
308 __func_imm_name(cbs, insn, full_imm: imm,
309 buff: tmp, len: sizeof(tmp)));
310 } else {
311 verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
312 return;
313 }
314 } else if (class == BPF_JMP32 || class == BPF_JMP) {
315 u8 opcode = BPF_OP(insn->code);
316
317 if (opcode == BPF_CALL) {
318 char tmp[64];
319
320 if (insn->src_reg == BPF_PSEUDO_CALL) {
321 verbose(cbs->private_data, "(%02x) call pc%s\n",
322 insn->code,
323 __func_get_name(cbs, insn,
324 buff: tmp, len: sizeof(tmp)));
325 } else {
326 strcpy(p: tmp, q: "unknown");
327 verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code,
328 __func_get_name(cbs, insn,
329 buff: tmp, len: sizeof(tmp)),
330 insn->imm);
331 }
332 } else if (insn->code == (BPF_JMP | BPF_JA)) {
333 verbose(cbs->private_data, "(%02x) goto pc%+d\n",
334 insn->code, insn->off);
335 } else if (insn->code == (BPF_JMP | BPF_JCOND) &&
336 insn->src_reg == BPF_MAY_GOTO) {
337 verbose(cbs->private_data, "(%02x) may_goto pc%+d\n",
338 insn->code, insn->off);
339 } else if (insn->code == (BPF_JMP32 | BPF_JA)) {
340 verbose(cbs->private_data, "(%02x) gotol pc%+d\n",
341 insn->code, insn->imm);
342 } else if (insn->code == (BPF_JMP | BPF_EXIT)) {
343 verbose(cbs->private_data, "(%02x) exit\n", insn->code);
344 } else if (BPF_SRC(insn->code) == BPF_X) {
345 verbose(cbs->private_data,
346 "(%02x) if %c%d %s %c%d goto pc%+d\n",
347 insn->code, class == BPF_JMP32 ? 'w' : 'r',
348 insn->dst_reg,
349 bpf_jmp_string[BPF_OP(insn->code) >> 4],
350 class == BPF_JMP32 ? 'w' : 'r',
351 insn->src_reg, insn->off);
352 } else {
353 verbose(cbs->private_data,
354 "(%02x) if %c%d %s 0x%x goto pc%+d\n",
355 insn->code, class == BPF_JMP32 ? 'w' : 'r',
356 insn->dst_reg,
357 bpf_jmp_string[BPF_OP(insn->code) >> 4],
358 insn->imm, insn->off);
359 }
360 } else {
361 verbose(cbs->private_data, "(%02x) %s\n",
362 insn->code, bpf_class_string[class]);
363 }
364}
365

source code of linux/kernel/bpf/disasm.c