projects/linux·blob v5.13 · refs

302 lines · 9.0 KiB

1// SPDX-License-Identifier: GPL-2.0-only
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(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
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(buff, len, "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_atomic_alu_string[16] = {
91 [BPF_ADD >> 4] = "add",
92 [BPF_AND >> 4] = "and",
93 [BPF_OR >> 4] = "or",
94 [BPF_XOR >> 4] = "xor",
95};
96
97static const char *const bpf_ldst_string[] = {
98 [BPF_W >> 3] = "u32",
99 [BPF_H >> 3] = "u16",
100 [BPF_B >> 3] = "u8",
101 [BPF_DW >> 3] = "u64",
102};
103
104static const char *const bpf_jmp_string[16] = {
105 [BPF_JA >> 4] = "jmp",
106 [BPF_JEQ >> 4] = "==",
107 [BPF_JGT >> 4] = ">",
108 [BPF_JLT >> 4] = "<",
109 [BPF_JGE >> 4] = ">=",
110 [BPF_JLE >> 4] = "<=",
111 [BPF_JSET >> 4] = "&",
112 [BPF_JNE >> 4] = "!=",
113 [BPF_JSGT >> 4] = "s>",
114 [BPF_JSLT >> 4] = "s<",
115 [BPF_JSGE >> 4] = "s>=",
116 [BPF_JSLE >> 4] = "s<=",
117 [BPF_CALL >> 4] = "call",
118 [BPF_EXIT >> 4] = "exit",
119};
120
121static void print_bpf_end_insn(bpf_insn_print_t verbose,
122 void *private_data,
123 const struct bpf_insn *insn)
124{
125 verbose(private_data, "(%02x) r%d = %s%d r%d\n",
126 insn->code, insn->dst_reg,
127 BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le",
128 insn->imm, insn->dst_reg);
129}
130
131void print_bpf_insn(const struct bpf_insn_cbs *cbs,
132 const struct bpf_insn *insn,
133 bool allow_ptr_leaks)
134{
135 const bpf_insn_print_t verbose = cbs->cb_print;
136 u8 class = BPF_CLASS(insn->code);
137
138 if (class == BPF_ALU || class == BPF_ALU64) {
139 if (BPF_OP(insn->code) == BPF_END) {
140 if (class == BPF_ALU64)
141 verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code);
142 else
143 print_bpf_end_insn(verbose, cbs->private_data, insn);
144 } else if (BPF_OP(insn->code) == BPF_NEG) {
145 verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n",
146 insn->code, class == BPF_ALU ? 'w' : 'r',
147 insn->dst_reg, class == BPF_ALU ? 'w' : 'r',
148 insn->dst_reg);
149 } else if (BPF_SRC(insn->code) == BPF_X) {
150 verbose(cbs->private_data, "(%02x) %c%d %s %c%d\n",
151 insn->code, class == BPF_ALU ? 'w' : 'r',
152 insn->dst_reg,
153 bpf_alu_string[BPF_OP(insn->code) >> 4],
154 class == BPF_ALU ? 'w' : 'r',
155 insn->src_reg);
156 } else {
157 verbose(cbs->private_data, "(%02x) %c%d %s %d\n",
158 insn->code, class == BPF_ALU ? 'w' : 'r',
159 insn->dst_reg,
160 bpf_alu_string[BPF_OP(insn->code) >> 4],
161 insn->imm);
162 }
163 } else if (class == BPF_STX) {
164 if (BPF_MODE(insn->code) == BPF_MEM)
165 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n",
166 insn->code,
167 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
168 insn->dst_reg,
169 insn->off, insn->src_reg);
170 else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
171 (insn->imm == BPF_ADD || insn->imm == BPF_AND ||
172 insn->imm == BPF_OR || insn->imm == BPF_XOR)) {
173 verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) %s r%d\n",
174 insn->code,
175 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
176 insn->dst_reg, insn->off,
177 bpf_alu_string[BPF_OP(insn->imm) >> 4],
178 insn->src_reg);
179 } else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
180 (insn->imm == (BPF_ADD | BPF_FETCH) ||
181 insn->imm == (BPF_AND | BPF_FETCH) ||
182 insn->imm == (BPF_OR | BPF_FETCH) ||
183 insn->imm == (BPF_XOR | BPF_FETCH))) {
184 verbose(cbs->private_data, "(%02x) r%d = atomic%s_fetch_%s((%s *)(r%d %+d), r%d)\n",
185 insn->code, insn->src_reg,
186 BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
187 bpf_atomic_alu_string[BPF_OP(insn->imm) >> 4],
188 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
189 insn->dst_reg, insn->off, insn->src_reg);
190 } else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
191 insn->imm == BPF_CMPXCHG) {
192 verbose(cbs->private_data, "(%02x) r0 = atomic%s_cmpxchg((%s *)(r%d %+d), r0, r%d)\n",
193 insn->code,
194 BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
195 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
196 insn->dst_reg, insn->off,
197 insn->src_reg);
198 } else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
199 insn->imm == BPF_XCHG) {
200 verbose(cbs->private_data, "(%02x) r%d = atomic%s_xchg((%s *)(r%d %+d), r%d)\n",
201 insn->code, insn->src_reg,
202 BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
203 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
204 insn->dst_reg, insn->off, insn->src_reg);
205 } else {
206 verbose(cbs->private_data, "BUG_%02x\n", insn->code);
207 }
208 } else if (class == BPF_ST) {
209 if (BPF_MODE(insn->code) != BPF_MEM) {
210 verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
211 return;
212 }
213 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n",
214 insn->code,
215 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
216 insn->dst_reg,
217 insn->off, insn->imm);
218 } else if (class == BPF_LDX) {
219 if (BPF_MODE(insn->code) != BPF_MEM) {
220 verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
221 return;
222 }
223 verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n",
224 insn->code, insn->dst_reg,
225 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
226 insn->src_reg, insn->off);
227 } else if (class == BPF_LD) {
228 if (BPF_MODE(insn->code) == BPF_ABS) {
229 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n",
230 insn->code,
231 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
232 insn->imm);
233 } else if (BPF_MODE(insn->code) == BPF_IND) {
234 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
235 insn->code,
236 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
237 insn->src_reg, insn->imm);
238 } else if (BPF_MODE(insn->code) == BPF_IMM &&
239 BPF_SIZE(insn->code) == BPF_DW) {
240 /* At this point, we already made sure that the second
241 * part of the ldimm64 insn is accessible.
242 */
243 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
244 bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD ||
245 insn->src_reg == BPF_PSEUDO_MAP_VALUE;
246 char tmp[64];
247
248 if (is_ptr && !allow_ptr_leaks)
249 imm = 0;
250
251 verbose(cbs->private_data, "(%02x) r%d = %s\n",
252 insn->code, insn->dst_reg,
253 __func_imm_name(cbs, insn, imm,
254 tmp, sizeof(tmp)));
255 } else {
256 verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
257 return;
258 }
259 } else if (class == BPF_JMP32 || class == BPF_JMP) {
260 u8 opcode = BPF_OP(insn->code);
261
262 if (opcode == BPF_CALL) {
263 char tmp[64];
264
265 if (insn->src_reg == BPF_PSEUDO_CALL) {
266 verbose(cbs->private_data, "(%02x) call pc%s\n",
267 insn->code,
268 __func_get_name(cbs, insn,
269 tmp, sizeof(tmp)));
270 } else {
271 strcpy(tmp, "unknown");
272 verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code,
273 __func_get_name(cbs, insn,
274 tmp, sizeof(tmp)),
275 insn->imm);
276 }
277 } else if (insn->code == (BPF_JMP | BPF_JA)) {
278 verbose(cbs->private_data, "(%02x) goto pc%+d\n",
279 insn->code, insn->off);
280 } else if (insn->code == (BPF_JMP | BPF_EXIT)) {
281 verbose(cbs->private_data, "(%02x) exit\n", insn->code);
282 } else if (BPF_SRC(insn->code) == BPF_X) {
283 verbose(cbs->private_data,
284 "(%02x) if %c%d %s %c%d goto pc%+d\n",
285 insn->code, class == BPF_JMP32 ? 'w' : 'r',
286 insn->dst_reg,
287 bpf_jmp_string[BPF_OP(insn->code) >> 4],
288 class == BPF_JMP32 ? 'w' : 'r',
289 insn->src_reg, insn->off);
290 } else {
291 verbose(cbs->private_data,
292 "(%02x) if %c%d %s 0x%x goto pc%+d\n",
293 insn->code, class == BPF_JMP32 ? 'w' : 'r',
294 insn->dst_reg,
295 bpf_jmp_string[BPF_OP(insn->code) >> 4],
296 insn->imm, insn->off);
297 }
298 } else {
299 verbose(cbs->private_data, "(%02x) %s\n",
300 insn->code, bpf_class_string[class]);
301 }
302}