1 /*
2 * Linux Socket Filter Data Structures
3 */
4 #ifndef __LINUX_FILTER_H__
5 #define __LINUX_FILTER_H__
6
7 #include <stdarg.h>
8
9 #include <linux/atomic.h>
10 #include <linux/compat.h>
11 #include <linux/skbuff.h>
12 #include <linux/linkage.h>
13 #include <linux/printk.h>
14 #include <linux/workqueue.h>
15
16 #include <asm/cacheflush.h>
17
18 #include <uapi/linux/filter.h>
19 #include <uapi/linux/bpf.h>
20
21 struct sk_buff;
22 struct sock;
23 struct seccomp_data;
24 struct bpf_prog_aux;
25
26 /* ArgX, context and stack frame pointer register positions. Note,
27 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
28 * calls in BPF_CALL instruction.
29 */
30 #define BPF_REG_ARG1 BPF_REG_1
31 #define BPF_REG_ARG2 BPF_REG_2
32 #define BPF_REG_ARG3 BPF_REG_3
33 #define BPF_REG_ARG4 BPF_REG_4
34 #define BPF_REG_ARG5 BPF_REG_5
35 #define BPF_REG_CTX BPF_REG_6
36 #define BPF_REG_FP BPF_REG_10
37
38 /* Additional register mappings for converted user programs. */
39 #define BPF_REG_A BPF_REG_0
40 #define BPF_REG_X BPF_REG_7
41 #define BPF_REG_TMP BPF_REG_8
42
43 /* BPF program can access up to 512 bytes of stack space. */
44 #define MAX_BPF_STACK 512
45
46 /* Helper macros for filter block array initializers. */
47
48 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
49
50 #define BPF_ALU64_REG(OP, DST, SRC) \
51 ((struct bpf_insn) { \
52 .code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \
53 .dst_reg = DST, \
54 .src_reg = SRC, \
55 .off = 0, \
56 .imm = 0 })
57
58 #define BPF_ALU32_REG(OP, DST, SRC) \
59 ((struct bpf_insn) { \
60 .code = BPF_ALU | BPF_OP(OP) | BPF_X, \
61 .dst_reg = DST, \
62 .src_reg = SRC, \
63 .off = 0, \
64 .imm = 0 })
65
66 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
67
68 #define BPF_ALU64_IMM(OP, DST, IMM) \
69 ((struct bpf_insn) { \
70 .code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \
71 .dst_reg = DST, \
72 .src_reg = 0, \
73 .off = 0, \
74 .imm = IMM })
75
76 #define BPF_ALU32_IMM(OP, DST, IMM) \
77 ((struct bpf_insn) { \
78 .code = BPF_ALU | BPF_OP(OP) | BPF_K, \
79 .dst_reg = DST, \
80 .src_reg = 0, \
81 .off = 0, \
82 .imm = IMM })
83
84 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
85
86 #define BPF_ENDIAN(TYPE, DST, LEN) \
87 ((struct bpf_insn) { \
88 .code = BPF_ALU | BPF_END | BPF_SRC(TYPE), \
89 .dst_reg = DST, \
90 .src_reg = 0, \
91 .off = 0, \
92 .imm = LEN })
93
94 /* Short form of mov, dst_reg = src_reg */
95
96 #define BPF_MOV64_REG(DST, SRC) \
97 ((struct bpf_insn) { \
98 .code = BPF_ALU64 | BPF_MOV | BPF_X, \
99 .dst_reg = DST, \
100 .src_reg = SRC, \
101 .off = 0, \
102 .imm = 0 })
103
104 #define BPF_MOV32_REG(DST, SRC) \
105 ((struct bpf_insn) { \
106 .code = BPF_ALU | BPF_MOV | BPF_X, \
107 .dst_reg = DST, \
108 .src_reg = SRC, \
109 .off = 0, \
110 .imm = 0 })
111
112 /* Short form of mov, dst_reg = imm32 */
113
114 #define BPF_MOV64_IMM(DST, IMM) \
115 ((struct bpf_insn) { \
116 .code = BPF_ALU64 | BPF_MOV | BPF_K, \
117 .dst_reg = DST, \
118 .src_reg = 0, \
119 .off = 0, \
120 .imm = IMM })
121
122 #define BPF_MOV32_IMM(DST, IMM) \
123 ((struct bpf_insn) { \
124 .code = BPF_ALU | BPF_MOV | BPF_K, \
125 .dst_reg = DST, \
126 .src_reg = 0, \
127 .off = 0, \
128 .imm = IMM })
129
130 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
131 #define BPF_LD_IMM64(DST, IMM) \
132 BPF_LD_IMM64_RAW(DST, 0, IMM)
133
134 #define BPF_LD_IMM64_RAW(DST, SRC, IMM) \
135 ((struct bpf_insn) { \
136 .code = BPF_LD | BPF_DW | BPF_IMM, \
137 .dst_reg = DST, \
138 .src_reg = SRC, \
139 .off = 0, \
140 .imm = (__u32) (IMM) }), \
141 ((struct bpf_insn) { \
142 .code = 0, /* zero is reserved opcode */ \
143 .dst_reg = 0, \
144 .src_reg = 0, \
145 .off = 0, \
146 .imm = ((__u64) (IMM)) >> 32 })
147
148 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
149 #define BPF_LD_MAP_FD(DST, MAP_FD) \
150 BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
151
152 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
153
154 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM) \
155 ((struct bpf_insn) { \
156 .code = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE), \
157 .dst_reg = DST, \
158 .src_reg = SRC, \
159 .off = 0, \
160 .imm = IMM })
161
162 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM) \
163 ((struct bpf_insn) { \
164 .code = BPF_ALU | BPF_MOV | BPF_SRC(TYPE), \
165 .dst_reg = DST, \
166 .src_reg = SRC, \
167 .off = 0, \
168 .imm = IMM })
169
170 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
171
172 #define BPF_LD_ABS(SIZE, IMM) \
173 ((struct bpf_insn) { \
174 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \
175 .dst_reg = 0, \
176 .src_reg = 0, \
177 .off = 0, \
178 .imm = IMM })
179
180 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
181
182 #define BPF_LD_IND(SIZE, SRC, IMM) \
183 ((struct bpf_insn) { \
184 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_IND, \
185 .dst_reg = 0, \
186 .src_reg = SRC, \
187 .off = 0, \
188 .imm = IMM })
189
190 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
191
192 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \
193 ((struct bpf_insn) { \
194 .code = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM, \
195 .dst_reg = DST, \
196 .src_reg = SRC, \
197 .off = OFF, \
198 .imm = 0 })
199
200 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
201
202 #define BPF_STX_MEM(SIZE, DST, SRC, OFF) \
203 ((struct bpf_insn) { \
204 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM, \
205 .dst_reg = DST, \
206 .src_reg = SRC, \
207 .off = OFF, \
208 .imm = 0 })
209
210 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
211
212 #define BPF_ST_MEM(SIZE, DST, OFF, IMM) \
213 ((struct bpf_insn) { \
214 .code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \
215 .dst_reg = DST, \
216 .src_reg = 0, \
217 .off = OFF, \
218 .imm = IMM })
219
220 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
221
222 #define BPF_JMP_REG(OP, DST, SRC, OFF) \
223 ((struct bpf_insn) { \
224 .code = BPF_JMP | BPF_OP(OP) | BPF_X, \
225 .dst_reg = DST, \
226 .src_reg = SRC, \
227 .off = OFF, \
228 .imm = 0 })
229
230 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
231
232 #define BPF_JMP_IMM(OP, DST, IMM, OFF) \
233 ((struct bpf_insn) { \
234 .code = BPF_JMP | BPF_OP(OP) | BPF_K, \
235 .dst_reg = DST, \
236 .src_reg = 0, \
237 .off = OFF, \
238 .imm = IMM })
239
240 /* Function call */
241
242 #define BPF_EMIT_CALL(FUNC) \
243 ((struct bpf_insn) { \
244 .code = BPF_JMP | BPF_CALL, \
245 .dst_reg = 0, \
246 .src_reg = 0, \
247 .off = 0, \
248 .imm = ((FUNC) - __bpf_call_base) })
249
250 /* Raw code statement block */
251
252 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \
253 ((struct bpf_insn) { \
254 .code = CODE, \
255 .dst_reg = DST, \
256 .src_reg = SRC, \
257 .off = OFF, \
258 .imm = IMM })
259
260 /* Program exit */
261
262 #define BPF_EXIT_INSN() \
263 ((struct bpf_insn) { \
264 .code = BPF_JMP | BPF_EXIT, \
265 .dst_reg = 0, \
266 .src_reg = 0, \
267 .off = 0, \
268 .imm = 0 })
269
270 #define bytes_to_bpf_size(bytes) \
271 ({ \
272 int bpf_size = -EINVAL; \
273 \
274 if (bytes == sizeof(u8)) \
275 bpf_size = BPF_B; \
276 else if (bytes == sizeof(u16)) \
277 bpf_size = BPF_H; \
278 else if (bytes == sizeof(u32)) \
279 bpf_size = BPF_W; \
280 else if (bytes == sizeof(u64)) \
281 bpf_size = BPF_DW; \
282 \
283 bpf_size; \
284 })
285
286 /* Macro to invoke filter function. */
287 #define SK_RUN_FILTER(filter, ctx) \
288 (*filter->prog->bpf_func)(ctx, filter->prog->insnsi)
289
290 #ifdef CONFIG_COMPAT
291 /* A struct sock_filter is architecture independent. */
292 struct compat_sock_fprog {
293 u16 len;
294 compat_uptr_t filter; /* struct sock_filter * */
295 };
296 #endif
297
298 struct sock_fprog_kern {
299 u16 len;
300 struct sock_filter *filter;
301 };
302
303 struct bpf_binary_header {
304 unsigned int pages;
305 u8 image[];
306 };
307
308 struct bpf_prog {
309 u16 pages; /* Number of allocated pages */
310 bool jited; /* Is our filter JIT'ed? */
311 bool gpl_compatible; /* Is our filter GPL compatible? */
312 u32 len; /* Number of filter blocks */
313 enum bpf_prog_type type; /* Type of BPF program */
314 struct bpf_prog_aux *aux; /* Auxiliary fields */
315 struct sock_fprog_kern *orig_prog; /* Original BPF program */
316 unsigned int (*bpf_func)(const struct sk_buff *skb,
317 const struct bpf_insn *filter);
318 /* Instructions for interpreter */
319 union {
320 struct sock_filter insns[0];
321 struct bpf_insn insnsi[0];
322 };
323 };
324
325 struct sk_filter {
326 atomic_t refcnt;
327 struct rcu_head rcu;
328 struct bpf_prog *prog;
329 };
330
331 #define BPF_PROG_RUN(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi)
332
bpf_prog_size(unsigned int proglen)333 static inline unsigned int bpf_prog_size(unsigned int proglen)
334 {
335 return max(sizeof(struct bpf_prog),
336 offsetof(struct bpf_prog, insns[proglen]));
337 }
338
339 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
340
341 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
bpf_prog_lock_ro(struct bpf_prog * fp)342 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
343 {
344 set_memory_ro((unsigned long)fp, fp->pages);
345 }
346
bpf_prog_unlock_ro(struct bpf_prog * fp)347 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
348 {
349 set_memory_rw((unsigned long)fp, fp->pages);
350 }
351 #else
bpf_prog_lock_ro(struct bpf_prog * fp)352 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
353 {
354 }
355
bpf_prog_unlock_ro(struct bpf_prog * fp)356 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
357 {
358 }
359 #endif /* CONFIG_DEBUG_SET_MODULE_RONX */
360
361 int sk_filter(struct sock *sk, struct sk_buff *skb);
362
363 void bpf_prog_select_runtime(struct bpf_prog *fp);
364 void bpf_prog_free(struct bpf_prog *fp);
365
366 int bpf_convert_filter(struct sock_filter *prog, int len,
367 struct bpf_insn *new_prog, int *new_len);
368
369 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
370 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
371 gfp_t gfp_extra_flags);
372 void __bpf_prog_free(struct bpf_prog *fp);
373
bpf_prog_unlock_free(struct bpf_prog * fp)374 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
375 {
376 bpf_prog_unlock_ro(fp);
377 __bpf_prog_free(fp);
378 }
379
380 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
381 void bpf_prog_destroy(struct bpf_prog *fp);
382
383 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
384 int sk_attach_bpf(u32 ufd, struct sock *sk);
385 int sk_detach_filter(struct sock *sk);
386
387 int bpf_check_classic(const struct sock_filter *filter, unsigned int flen);
388 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
389 unsigned int len);
390
391 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
392 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
393
394 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
395 void bpf_int_jit_compile(struct bpf_prog *fp);
396
397 #ifdef CONFIG_BPF_JIT
398 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
399
400 struct bpf_binary_header *
401 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
402 unsigned int alignment,
403 bpf_jit_fill_hole_t bpf_fill_ill_insns);
404 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
405
406 void bpf_jit_compile(struct bpf_prog *fp);
407 void bpf_jit_free(struct bpf_prog *fp);
408
bpf_jit_dump(unsigned int flen,unsigned int proglen,u32 pass,void * image)409 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
410 u32 pass, void *image)
411 {
412 pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
413 flen, proglen, pass, image);
414 if (image)
415 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
416 16, 1, image, proglen, false);
417 }
418 #else
bpf_jit_compile(struct bpf_prog * fp)419 static inline void bpf_jit_compile(struct bpf_prog *fp)
420 {
421 }
422
bpf_jit_free(struct bpf_prog * fp)423 static inline void bpf_jit_free(struct bpf_prog *fp)
424 {
425 bpf_prog_unlock_free(fp);
426 }
427 #endif /* CONFIG_BPF_JIT */
428
429 #define BPF_ANC BIT(15)
430
bpf_needs_clear_a(const struct sock_filter * first)431 static inline bool bpf_needs_clear_a(const struct sock_filter *first)
432 {
433 switch (first->code) {
434 case BPF_RET | BPF_K:
435 case BPF_LD | BPF_W | BPF_LEN:
436 return false;
437
438 case BPF_LD | BPF_W | BPF_ABS:
439 case BPF_LD | BPF_H | BPF_ABS:
440 case BPF_LD | BPF_B | BPF_ABS:
441 if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
442 return true;
443 return false;
444
445 default:
446 return true;
447 }
448 }
449
bpf_anc_helper(const struct sock_filter * ftest)450 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
451 {
452 BUG_ON(ftest->code & BPF_ANC);
453
454 switch (ftest->code) {
455 case BPF_LD | BPF_W | BPF_ABS:
456 case BPF_LD | BPF_H | BPF_ABS:
457 case BPF_LD | BPF_B | BPF_ABS:
458 #define BPF_ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \
459 return BPF_ANC | SKF_AD_##CODE
460 switch (ftest->k) {
461 BPF_ANCILLARY(PROTOCOL);
462 BPF_ANCILLARY(PKTTYPE);
463 BPF_ANCILLARY(IFINDEX);
464 BPF_ANCILLARY(NLATTR);
465 BPF_ANCILLARY(NLATTR_NEST);
466 BPF_ANCILLARY(MARK);
467 BPF_ANCILLARY(QUEUE);
468 BPF_ANCILLARY(HATYPE);
469 BPF_ANCILLARY(RXHASH);
470 BPF_ANCILLARY(CPU);
471 BPF_ANCILLARY(ALU_XOR_X);
472 BPF_ANCILLARY(VLAN_TAG);
473 BPF_ANCILLARY(VLAN_TAG_PRESENT);
474 BPF_ANCILLARY(PAY_OFFSET);
475 BPF_ANCILLARY(RANDOM);
476 BPF_ANCILLARY(VLAN_TPID);
477 }
478 /* Fallthrough. */
479 default:
480 return ftest->code;
481 }
482 }
483
484 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
485 int k, unsigned int size);
486
bpf_load_pointer(const struct sk_buff * skb,int k,unsigned int size,void * buffer)487 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
488 unsigned int size, void *buffer)
489 {
490 if (k >= 0)
491 return skb_header_pointer(skb, k, size, buffer);
492
493 return bpf_internal_load_pointer_neg_helper(skb, k, size);
494 }
495
bpf_tell_extensions(void)496 static inline int bpf_tell_extensions(void)
497 {
498 return SKF_AD_MAX;
499 }
500
501 #endif /* __LINUX_FILTER_H__ */
502