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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 #define BPF_PSEUDO_MAP_FD	1
149 
150 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
151 #define BPF_LD_MAP_FD(DST, MAP_FD)				\
152 	BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
153 
154 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
155 
156 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)			\
157 	((struct bpf_insn) {					\
158 		.code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),	\
159 		.dst_reg = DST,					\
160 		.src_reg = SRC,					\
161 		.off   = 0,					\
162 		.imm   = IMM })
163 
164 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)			\
165 	((struct bpf_insn) {					\
166 		.code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),	\
167 		.dst_reg = DST,					\
168 		.src_reg = SRC,					\
169 		.off   = 0,					\
170 		.imm   = IMM })
171 
172 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
173 
174 #define BPF_LD_ABS(SIZE, IMM)					\
175 	((struct bpf_insn) {					\
176 		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,	\
177 		.dst_reg = 0,					\
178 		.src_reg = 0,					\
179 		.off   = 0,					\
180 		.imm   = IMM })
181 
182 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
183 
184 #define BPF_LD_IND(SIZE, SRC, IMM)				\
185 	((struct bpf_insn) {					\
186 		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,	\
187 		.dst_reg = 0,					\
188 		.src_reg = SRC,					\
189 		.off   = 0,					\
190 		.imm   = IMM })
191 
192 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
193 
194 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF)			\
195 	((struct bpf_insn) {					\
196 		.code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,	\
197 		.dst_reg = DST,					\
198 		.src_reg = SRC,					\
199 		.off   = OFF,					\
200 		.imm   = 0 })
201 
202 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
203 
204 #define BPF_STX_MEM(SIZE, DST, SRC, OFF)			\
205 	((struct bpf_insn) {					\
206 		.code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,	\
207 		.dst_reg = DST,					\
208 		.src_reg = SRC,					\
209 		.off   = OFF,					\
210 		.imm   = 0 })
211 
212 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
213 
214 #define BPF_ST_MEM(SIZE, DST, OFF, IMM)				\
215 	((struct bpf_insn) {					\
216 		.code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,	\
217 		.dst_reg = DST,					\
218 		.src_reg = 0,					\
219 		.off   = OFF,					\
220 		.imm   = IMM })
221 
222 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
223 
224 #define BPF_JMP_REG(OP, DST, SRC, OFF)				\
225 	((struct bpf_insn) {					\
226 		.code  = BPF_JMP | BPF_OP(OP) | BPF_X,		\
227 		.dst_reg = DST,					\
228 		.src_reg = SRC,					\
229 		.off   = OFF,					\
230 		.imm   = 0 })
231 
232 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
233 
234 #define BPF_JMP_IMM(OP, DST, IMM, OFF)				\
235 	((struct bpf_insn) {					\
236 		.code  = BPF_JMP | BPF_OP(OP) | BPF_K,		\
237 		.dst_reg = DST,					\
238 		.src_reg = 0,					\
239 		.off   = OFF,					\
240 		.imm   = IMM })
241 
242 /* Function call */
243 
244 #define BPF_EMIT_CALL(FUNC)					\
245 	((struct bpf_insn) {					\
246 		.code  = BPF_JMP | BPF_CALL,			\
247 		.dst_reg = 0,					\
248 		.src_reg = 0,					\
249 		.off   = 0,					\
250 		.imm   = ((FUNC) - __bpf_call_base) })
251 
252 /* Raw code statement block */
253 
254 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)			\
255 	((struct bpf_insn) {					\
256 		.code  = CODE,					\
257 		.dst_reg = DST,					\
258 		.src_reg = SRC,					\
259 		.off   = OFF,					\
260 		.imm   = IMM })
261 
262 /* Program exit */
263 
264 #define BPF_EXIT_INSN()						\
265 	((struct bpf_insn) {					\
266 		.code  = BPF_JMP | BPF_EXIT,			\
267 		.dst_reg = 0,					\
268 		.src_reg = 0,					\
269 		.off   = 0,					\
270 		.imm   = 0 })
271 
272 #define bytes_to_bpf_size(bytes)				\
273 ({								\
274 	int bpf_size = -EINVAL;					\
275 								\
276 	if (bytes == sizeof(u8))				\
277 		bpf_size = BPF_B;				\
278 	else if (bytes == sizeof(u16))				\
279 		bpf_size = BPF_H;				\
280 	else if (bytes == sizeof(u32))				\
281 		bpf_size = BPF_W;				\
282 	else if (bytes == sizeof(u64))				\
283 		bpf_size = BPF_DW;				\
284 								\
285 	bpf_size;						\
286 })
287 
288 /* Macro to invoke filter function. */
289 #define SK_RUN_FILTER(filter, ctx) \
290 	(*filter->prog->bpf_func)(ctx, filter->prog->insnsi)
291 
292 #ifdef CONFIG_COMPAT
293 /* A struct sock_filter is architecture independent. */
294 struct compat_sock_fprog {
295 	u16		len;
296 	compat_uptr_t	filter;	/* struct sock_filter * */
297 };
298 #endif
299 
300 struct sock_fprog_kern {
301 	u16			len;
302 	struct sock_filter	*filter;
303 };
304 
305 struct bpf_binary_header {
306 	unsigned int pages;
307 	u8 image[];
308 };
309 
310 struct bpf_prog {
311 	u16			pages;		/* Number of allocated pages */
312 	bool			jited;		/* Is our filter JIT'ed? */
313 	u32			len;		/* Number of filter blocks */
314 	struct sock_fprog_kern	*orig_prog;	/* Original BPF program */
315 	struct bpf_prog_aux	*aux;		/* Auxiliary fields */
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_detach_filter(struct sock *sk);
385 
386 int bpf_check_classic(const struct sock_filter *filter, unsigned int flen);
387 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
388 		  unsigned int len);
389 
390 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
391 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
392 
393 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
394 void bpf_int_jit_compile(struct bpf_prog *fp);
395 
396 #ifdef CONFIG_BPF_JIT
397 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
398 
399 struct bpf_binary_header *
400 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
401 		     unsigned int alignment,
402 		     bpf_jit_fill_hole_t bpf_fill_ill_insns);
403 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
404 
405 void bpf_jit_compile(struct bpf_prog *fp);
406 void bpf_jit_free(struct bpf_prog *fp);
407 
bpf_jit_dump(unsigned int flen,unsigned int proglen,u32 pass,void * image)408 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
409 				u32 pass, void *image)
410 {
411 	pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
412 	       flen, proglen, pass, image);
413 	if (image)
414 		print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
415 			       16, 1, image, proglen, false);
416 }
417 #else
bpf_jit_compile(struct bpf_prog * fp)418 static inline void bpf_jit_compile(struct bpf_prog *fp)
419 {
420 }
421 
bpf_jit_free(struct bpf_prog * fp)422 static inline void bpf_jit_free(struct bpf_prog *fp)
423 {
424 	bpf_prog_unlock_free(fp);
425 }
426 #endif /* CONFIG_BPF_JIT */
427 
428 #define BPF_ANC		BIT(15)
429 
bpf_needs_clear_a(const struct sock_filter * first)430 static inline bool bpf_needs_clear_a(const struct sock_filter *first)
431 {
432 	switch (first->code) {
433 	case BPF_RET | BPF_K:
434 	case BPF_LD | BPF_W | BPF_LEN:
435 		return false;
436 
437 	case BPF_LD | BPF_W | BPF_ABS:
438 	case BPF_LD | BPF_H | BPF_ABS:
439 	case BPF_LD | BPF_B | BPF_ABS:
440 		if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
441 			return true;
442 		return false;
443 
444 	default:
445 		return true;
446 	}
447 }
448 
bpf_anc_helper(const struct sock_filter * ftest)449 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
450 {
451 	BUG_ON(ftest->code & BPF_ANC);
452 
453 	switch (ftest->code) {
454 	case BPF_LD | BPF_W | BPF_ABS:
455 	case BPF_LD | BPF_H | BPF_ABS:
456 	case BPF_LD | BPF_B | BPF_ABS:
457 #define BPF_ANCILLARY(CODE)	case SKF_AD_OFF + SKF_AD_##CODE:	\
458 				return BPF_ANC | SKF_AD_##CODE
459 		switch (ftest->k) {
460 		BPF_ANCILLARY(PROTOCOL);
461 		BPF_ANCILLARY(PKTTYPE);
462 		BPF_ANCILLARY(IFINDEX);
463 		BPF_ANCILLARY(NLATTR);
464 		BPF_ANCILLARY(NLATTR_NEST);
465 		BPF_ANCILLARY(MARK);
466 		BPF_ANCILLARY(QUEUE);
467 		BPF_ANCILLARY(HATYPE);
468 		BPF_ANCILLARY(RXHASH);
469 		BPF_ANCILLARY(CPU);
470 		BPF_ANCILLARY(ALU_XOR_X);
471 		BPF_ANCILLARY(VLAN_TAG);
472 		BPF_ANCILLARY(VLAN_TAG_PRESENT);
473 		BPF_ANCILLARY(PAY_OFFSET);
474 		BPF_ANCILLARY(RANDOM);
475 		}
476 		/* Fallthrough. */
477 	default:
478 		return ftest->code;
479 	}
480 }
481 
482 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
483 					   int k, unsigned int size);
484 
bpf_load_pointer(const struct sk_buff * skb,int k,unsigned int size,void * buffer)485 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
486 				     unsigned int size, void *buffer)
487 {
488 	if (k >= 0)
489 		return skb_header_pointer(skb, k, size, buffer);
490 
491 	return bpf_internal_load_pointer_neg_helper(skb, k, size);
492 }
493 
bpf_tell_extensions(void)494 static inline int bpf_tell_extensions(void)
495 {
496 	return SKF_AD_MAX;
497 }
498 
499 #endif /* __LINUX_FILTER_H__ */
500