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)
11 static const char * const func_id_str[] = {
12 __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
13 };
14 #undef __BPF_FUNC_STR_FN
15
16 static 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(buff, len, "%+d", insn->imm);
37 else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL)
38 snprintf(buff, len, "kernel-function");
39
40 return buff;
41 }
42
43 static 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(buff, len, "0x%llx", (unsigned long long)full_imm);
51 return buff;
52 }
53
54 const 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
62 const 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
73 const 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
90 static const char *const bpf_alu_sign_string[16] = {
91 [BPF_DIV >> 4] = "s/=",
92 [BPF_MOD >> 4] = "s%=",
93 };
94
95 static const char *const bpf_movsx_string[4] = {
96 [0] = "(s8)",
97 [1] = "(s16)",
98 [3] = "(s32)",
99 };
100
101 static 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
108 static 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
115 static const char *const bpf_ldsx_string[] = {
116 [BPF_W >> 3] = "s32",
117 [BPF_H >> 3] = "s16",
118 [BPF_B >> 3] = "s8",
119 };
120
121 static 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
138 static 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
148 static 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
157 static 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
163 static 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
169 static 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
175 /* Special (internal-only) form of mov, used to resolve per-CPU addrs:
176 * dst_reg = src_reg + <percpu_base_off>
177 * BPF_ADDR_PERCPU is used as a special insn->off value.
178 */
179 #define BPF_ADDR_PERCPU (-1)
180
181 static inline bool is_mov_percpu_addr(const struct bpf_insn *insn)
182 {
183 return insn->code == (BPF_ALU64 | BPF_MOV | BPF_X) && insn->off == BPF_ADDR_PERCPU;
184 }
185
186 void print_bpf_insn(const struct bpf_insn_cbs *cbs,
187 const struct bpf_insn *insn,
188 bool allow_ptr_leaks)
189 {
190 const bpf_insn_print_t verbose = cbs->cb_print;
191 u8 class = BPF_CLASS(insn->code);
192
193 if (class == BPF_ALU || class == BPF_ALU64) {
194 if (BPF_OP(insn->code) == BPF_END) {
195 if (class == BPF_ALU64)
196 print_bpf_bswap_insn(verbose, cbs->private_data, insn);
197 else
198 print_bpf_end_insn(verbose, cbs->private_data, insn);
199 } else if (BPF_OP(insn->code) == BPF_NEG) {
200 verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n",
201 insn->code, class == BPF_ALU ? 'w' : 'r',
202 insn->dst_reg, class == BPF_ALU ? 'w' : 'r',
203 insn->dst_reg);
204 } else if (is_addr_space_cast(insn)) {
205 verbose(cbs->private_data, "(%02x) r%d = addr_space_cast(r%d, %d, %d)\n",
206 insn->code, insn->dst_reg,
207 insn->src_reg, ((u32)insn->imm) >> 16, (u16)insn->imm);
208 } else if (is_mov_percpu_addr(insn)) {
209 verbose(cbs->private_data, "(%02x) r%d = &(void __percpu *)(r%d)\n",
210 insn->code, insn->dst_reg, insn->src_reg);
211 } else if (BPF_SRC(insn->code) == BPF_X) {
212 verbose(cbs->private_data, "(%02x) %c%d %s %s%c%d\n",
213 insn->code, class == BPF_ALU ? 'w' : 'r',
214 insn->dst_reg,
215 is_sdiv_smod(insn) ? bpf_alu_sign_string[BPF_OP(insn->code) >> 4]
216 : bpf_alu_string[BPF_OP(insn->code) >> 4],
217 is_movsx(insn) ? bpf_movsx_string[(insn->off >> 3) - 1] : "",
218 class == BPF_ALU ? 'w' : 'r',
219 insn->src_reg);
220 } else {
221 verbose(cbs->private_data, "(%02x) %c%d %s %d\n",
222 insn->code, class == BPF_ALU ? 'w' : 'r',
223 insn->dst_reg,
224 is_sdiv_smod(insn) ? bpf_alu_sign_string[BPF_OP(insn->code) >> 4]
225 : bpf_alu_string[BPF_OP(insn->code) >> 4],
226 insn->imm);
227 }
228 } else if (class == BPF_STX) {
229 if (BPF_MODE(insn->code) == BPF_MEM)
230 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n",
231 insn->code,
232 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
233 insn->dst_reg,
234 insn->off, insn->src_reg);
235 else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
236 (insn->imm == BPF_ADD || insn->imm == BPF_AND ||
237 insn->imm == BPF_OR || insn->imm == BPF_XOR)) {
238 verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) %s r%d\n",
239 insn->code,
240 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
241 insn->dst_reg, insn->off,
242 bpf_alu_string[BPF_OP(insn->imm) >> 4],
243 insn->src_reg);
244 } else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
245 (insn->imm == (BPF_ADD | BPF_FETCH) ||
246 insn->imm == (BPF_AND | BPF_FETCH) ||
247 insn->imm == (BPF_OR | BPF_FETCH) ||
248 insn->imm == (BPF_XOR | BPF_FETCH))) {
249 verbose(cbs->private_data, "(%02x) r%d = atomic%s_fetch_%s((%s *)(r%d %+d), r%d)\n",
250 insn->code, insn->src_reg,
251 BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
252 bpf_atomic_alu_string[BPF_OP(insn->imm) >> 4],
253 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
254 insn->dst_reg, insn->off, insn->src_reg);
255 } else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
256 insn->imm == BPF_CMPXCHG) {
257 verbose(cbs->private_data, "(%02x) r0 = atomic%s_cmpxchg((%s *)(r%d %+d), r0, r%d)\n",
258 insn->code,
259 BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
260 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
261 insn->dst_reg, insn->off,
262 insn->src_reg);
263 } else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
264 insn->imm == BPF_XCHG) {
265 verbose(cbs->private_data, "(%02x) r%d = atomic%s_xchg((%s *)(r%d %+d), r%d)\n",
266 insn->code, insn->src_reg,
267 BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
268 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
269 insn->dst_reg, insn->off, insn->src_reg);
270 } else {
271 verbose(cbs->private_data, "BUG_%02x\n", insn->code);
272 }
273 } else if (class == BPF_ST) {
274 if (BPF_MODE(insn->code) == BPF_MEM) {
275 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n",
276 insn->code,
277 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
278 insn->dst_reg,
279 insn->off, insn->imm);
280 } else if (BPF_MODE(insn->code) == 0xc0 /* BPF_NOSPEC, no UAPI */) {
281 verbose(cbs->private_data, "(%02x) nospec\n", insn->code);
282 } else {
283 verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
284 }
285 } else if (class == BPF_LDX) {
286 if (BPF_MODE(insn->code) != BPF_MEM && BPF_MODE(insn->code) != BPF_MEMSX) {
287 verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
288 return;
289 }
290 verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n",
291 insn->code, insn->dst_reg,
292 BPF_MODE(insn->code) == BPF_MEM ?
293 bpf_ldst_string[BPF_SIZE(insn->code) >> 3] :
294 bpf_ldsx_string[BPF_SIZE(insn->code) >> 3],
295 insn->src_reg, insn->off);
296 } else if (class == BPF_LD) {
297 if (BPF_MODE(insn->code) == BPF_ABS) {
298 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n",
299 insn->code,
300 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
301 insn->imm);
302 } else if (BPF_MODE(insn->code) == BPF_IND) {
303 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
304 insn->code,
305 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
306 insn->src_reg, insn->imm);
307 } else if (BPF_MODE(insn->code) == BPF_IMM &&
308 BPF_SIZE(insn->code) == BPF_DW) {
309 /* At this point, we already made sure that the second
310 * part of the ldimm64 insn is accessible.
311 */
312 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
313 bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD ||
314 insn->src_reg == BPF_PSEUDO_MAP_VALUE;
315 char tmp[64];
316
317 if (is_ptr && !allow_ptr_leaks)
318 imm = 0;
319
320 verbose(cbs->private_data, "(%02x) r%d = %s\n",
321 insn->code, insn->dst_reg,
322 __func_imm_name(cbs, insn, imm,
323 tmp, sizeof(tmp)));
324 } else {
325 verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
326 return;
327 }
328 } else if (class == BPF_JMP32 || class == BPF_JMP) {
329 u8 opcode = BPF_OP(insn->code);
330
331 if (opcode == BPF_CALL) {
332 char tmp[64];
333
334 if (insn->src_reg == BPF_PSEUDO_CALL) {
335 verbose(cbs->private_data, "(%02x) call pc%s\n",
336 insn->code,
337 __func_get_name(cbs, insn,
338 tmp, sizeof(tmp)));
339 } else {
340 strcpy(tmp, "unknown");
341 verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code,
342 __func_get_name(cbs, insn,
343 tmp, sizeof(tmp)),
344 insn->imm);
345 }
346 } else if (insn->code == (BPF_JMP | BPF_JA)) {
347 verbose(cbs->private_data, "(%02x) goto pc%+d\n",
348 insn->code, insn->off);
349 } else if (insn->code == (BPF_JMP | BPF_JCOND) &&
350 insn->src_reg == BPF_MAY_GOTO) {
351 verbose(cbs->private_data, "(%02x) may_goto pc%+d\n",
352 insn->code, insn->off);
353 } else if (insn->code == (BPF_JMP32 | BPF_JA)) {
354 verbose(cbs->private_data, "(%02x) gotol pc%+d\n",
355 insn->code, insn->imm);
356 } else if (insn->code == (BPF_JMP | BPF_EXIT)) {
357 verbose(cbs->private_data, "(%02x) exit\n", insn->code);
358 } else if (BPF_SRC(insn->code) == BPF_X) {
359 verbose(cbs->private_data,
360 "(%02x) if %c%d %s %c%d goto pc%+d\n",
361 insn->code, class == BPF_JMP32 ? 'w' : 'r',
362 insn->dst_reg,
363 bpf_jmp_string[BPF_OP(insn->code) >> 4],
364 class == BPF_JMP32 ? 'w' : 'r',
365 insn->src_reg, insn->off);
366 } else {
367 verbose(cbs->private_data,
368 "(%02x) if %c%d %s 0x%x goto pc%+d\n",
369 insn->code, class == BPF_JMP32 ? 'w' : 'r',
370 insn->dst_reg,
371 bpf_jmp_string[BPF_OP(insn->code) >> 4],
372 insn->imm, insn->off);
373 }
374 } else {
375 verbose(cbs->private_data, "(%02x) %s\n",
376 insn->code, bpf_class_string[class]);
377 }
378 }
379
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