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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#include <linux/sched.h>
16#include <net/sch_generic.h>
17
18#include <asm/cacheflush.h>
19
20#include <uapi/linux/filter.h>
21#include <uapi/linux/bpf.h>
22
23struct sk_buff;
24struct sock;
25struct seccomp_data;
26struct bpf_prog_aux;
27
28/* ArgX, context and stack frame pointer register positions. Note,
29 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
30 * calls in BPF_CALL instruction.
31 */
32#define BPF_REG_ARG1 BPF_REG_1
33#define BPF_REG_ARG2 BPF_REG_2
34#define BPF_REG_ARG3 BPF_REG_3
35#define BPF_REG_ARG4 BPF_REG_4
36#define BPF_REG_ARG5 BPF_REG_5
37#define BPF_REG_CTX BPF_REG_6
38#define BPF_REG_FP BPF_REG_10
39
40/* Additional register mappings for converted user programs. */
41#define BPF_REG_A BPF_REG_0
42#define BPF_REG_X BPF_REG_7
43#define BPF_REG_TMP BPF_REG_8
44
45/* BPF program can access up to 512 bytes of stack space. */
46#define MAX_BPF_STACK 512
47
48/* Helper macros for filter block array initializers. */
49
50/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
51
52#define BPF_ALU64_REG(OP, DST, SRC) \
53 ((struct bpf_insn) { \
54 .code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \
55 .dst_reg = DST, \
56 .src_reg = SRC, \
57 .off = 0, \
58 .imm = 0 })
59
60#define BPF_ALU32_REG(OP, DST, SRC) \
61 ((struct bpf_insn) { \
62 .code = BPF_ALU | BPF_OP(OP) | BPF_X, \
63 .dst_reg = DST, \
64 .src_reg = SRC, \
65 .off = 0, \
66 .imm = 0 })
67
68/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
69
70#define BPF_ALU64_IMM(OP, DST, IMM) \
71 ((struct bpf_insn) { \
72 .code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \
73 .dst_reg = DST, \
74 .src_reg = 0, \
75 .off = 0, \
76 .imm = IMM })
77
78#define BPF_ALU32_IMM(OP, DST, IMM) \
79 ((struct bpf_insn) { \
80 .code = BPF_ALU | BPF_OP(OP) | BPF_K, \
81 .dst_reg = DST, \
82 .src_reg = 0, \
83 .off = 0, \
84 .imm = IMM })
85
86/* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
87
88#define BPF_ENDIAN(TYPE, DST, LEN) \
89 ((struct bpf_insn) { \
90 .code = BPF_ALU | BPF_END | BPF_SRC(TYPE), \
91 .dst_reg = DST, \
92 .src_reg = 0, \
93 .off = 0, \
94 .imm = LEN })
95
96/* Short form of mov, dst_reg = src_reg */
97
98#define BPF_MOV64_REG(DST, SRC) \
99 ((struct bpf_insn) { \
100 .code = BPF_ALU64 | BPF_MOV | BPF_X, \
101 .dst_reg = DST, \
102 .src_reg = SRC, \
103 .off = 0, \
104 .imm = 0 })
105
106#define BPF_MOV32_REG(DST, SRC) \
107 ((struct bpf_insn) { \
108 .code = BPF_ALU | BPF_MOV | BPF_X, \
109 .dst_reg = DST, \
110 .src_reg = SRC, \
111 .off = 0, \
112 .imm = 0 })
113
114/* Short form of mov, dst_reg = imm32 */
115
116#define BPF_MOV64_IMM(DST, IMM) \
117 ((struct bpf_insn) { \
118 .code = BPF_ALU64 | BPF_MOV | BPF_K, \
119 .dst_reg = DST, \
120 .src_reg = 0, \
121 .off = 0, \
122 .imm = IMM })
123
124#define BPF_MOV32_IMM(DST, IMM) \
125 ((struct bpf_insn) { \
126 .code = BPF_ALU | BPF_MOV | BPF_K, \
127 .dst_reg = DST, \
128 .src_reg = 0, \
129 .off = 0, \
130 .imm = IMM })
131
132/* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
133#define BPF_LD_IMM64(DST, IMM) \
134 BPF_LD_IMM64_RAW(DST, 0, IMM)
135
136#define BPF_LD_IMM64_RAW(DST, SRC, IMM) \
137 ((struct bpf_insn) { \
138 .code = BPF_LD | BPF_DW | BPF_IMM, \
139 .dst_reg = DST, \
140 .src_reg = SRC, \
141 .off = 0, \
142 .imm = (__u32) (IMM) }), \
143 ((struct bpf_insn) { \
144 .code = 0, /* zero is reserved opcode */ \
145 .dst_reg = 0, \
146 .src_reg = 0, \
147 .off = 0, \
148 .imm = ((__u64) (IMM)) >> 32 })
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/* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
213
214#define BPF_STX_XADD(SIZE, DST, SRC, OFF) \
215 ((struct bpf_insn) { \
216 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD, \
217 .dst_reg = DST, \
218 .src_reg = SRC, \
219 .off = OFF, \
220 .imm = 0 })
221
222/* Memory store, *(uint *) (dst_reg + off16) = imm32 */
223
224#define BPF_ST_MEM(SIZE, DST, OFF, IMM) \
225 ((struct bpf_insn) { \
226 .code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \
227 .dst_reg = DST, \
228 .src_reg = 0, \
229 .off = OFF, \
230 .imm = IMM })
231
232/* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
233
234#define BPF_JMP_REG(OP, DST, SRC, OFF) \
235 ((struct bpf_insn) { \
236 .code = BPF_JMP | BPF_OP(OP) | BPF_X, \
237 .dst_reg = DST, \
238 .src_reg = SRC, \
239 .off = OFF, \
240 .imm = 0 })
241
242/* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
243
244#define BPF_JMP_IMM(OP, DST, IMM, OFF) \
245 ((struct bpf_insn) { \
246 .code = BPF_JMP | BPF_OP(OP) | BPF_K, \
247 .dst_reg = DST, \
248 .src_reg = 0, \
249 .off = OFF, \
250 .imm = IMM })
251
252/* Function call */
253
254#define BPF_EMIT_CALL(FUNC) \
255 ((struct bpf_insn) { \
256 .code = BPF_JMP | BPF_CALL, \
257 .dst_reg = 0, \
258 .src_reg = 0, \
259 .off = 0, \
260 .imm = ((FUNC) - __bpf_call_base) })
261
262/* Raw code statement block */
263
264#define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \
265 ((struct bpf_insn) { \
266 .code = CODE, \
267 .dst_reg = DST, \
268 .src_reg = SRC, \
269 .off = OFF, \
270 .imm = IMM })
271
272/* Program exit */
273
274#define BPF_EXIT_INSN() \
275 ((struct bpf_insn) { \
276 .code = BPF_JMP | BPF_EXIT, \
277 .dst_reg = 0, \
278 .src_reg = 0, \
279 .off = 0, \
280 .imm = 0 })
281
282/* Internal classic blocks for direct assignment */
283
284#define __BPF_STMT(CODE, K) \
285 ((struct sock_filter) BPF_STMT(CODE, K))
286
287#define __BPF_JUMP(CODE, K, JT, JF) \
288 ((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))
289
290#define bytes_to_bpf_size(bytes) \
291({ \
292 int bpf_size = -EINVAL; \
293 \
294 if (bytes == sizeof(u8)) \
295 bpf_size = BPF_B; \
296 else if (bytes == sizeof(u16)) \
297 bpf_size = BPF_H; \
298 else if (bytes == sizeof(u32)) \
299 bpf_size = BPF_W; \
300 else if (bytes == sizeof(u64)) \
301 bpf_size = BPF_DW; \
302 \
303 bpf_size; \
304})
305
306#ifdef CONFIG_COMPAT
307/* A struct sock_filter is architecture independent. */
308struct compat_sock_fprog {
309 u16 len;
310 compat_uptr_t filter; /* struct sock_filter * */
311};
312#endif
313
314struct sock_fprog_kern {
315 u16 len;
316 struct sock_filter *filter;
317};
318
319struct bpf_binary_header {
320 unsigned int pages;
321 u8 image[];
322};
323
324struct bpf_prog {
325 u16 pages; /* Number of allocated pages */
326 kmemcheck_bitfield_begin(meta);
327 u16 jited:1, /* Is our filter JIT'ed? */
328 gpl_compatible:1, /* Is filter GPL compatible? */
329 cb_access:1, /* Is control block accessed? */
330 dst_needed:1; /* Do we need dst entry? */
331 kmemcheck_bitfield_end(meta);
332 u32 len; /* Number of filter blocks */
333 enum bpf_prog_type type; /* Type of BPF program */
334 struct bpf_prog_aux *aux; /* Auxiliary fields */
335 struct sock_fprog_kern *orig_prog; /* Original BPF program */
336 unsigned int (*bpf_func)(const struct sk_buff *skb,
337 const struct bpf_insn *filter);
338 /* Instructions for interpreter */
339 union {
340 struct sock_filter insns[0];
341 struct bpf_insn insnsi[0];
342 };
343};
344
345struct sk_filter {
346 atomic_t refcnt;
347 struct rcu_head rcu;
348 struct bpf_prog *prog;
349};
350
351#define BPF_PROG_RUN(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi)
352
353#define BPF_SKB_CB_LEN QDISC_CB_PRIV_LEN
354
355struct bpf_skb_data_end {
356 struct qdisc_skb_cb qdisc_cb;
357 void *data_end;
358};
359
360/* compute the linear packet data range [data, data_end) which
361 * will be accessed by cls_bpf and act_bpf programs
362 */
363static inline void bpf_compute_data_end(struct sk_buff *skb)
364{
365 struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb;
366
367 BUILD_BUG_ON(sizeof(*cb) > FIELD_SIZEOF(struct sk_buff, cb));
368 cb->data_end = skb->data + skb_headlen(skb);
369}
370
371static inline u8 *bpf_skb_cb(struct sk_buff *skb)
372{
373 /* eBPF programs may read/write skb->cb[] area to transfer meta
374 * data between tail calls. Since this also needs to work with
375 * tc, that scratch memory is mapped to qdisc_skb_cb's data area.
376 *
377 * In some socket filter cases, the cb unfortunately needs to be
378 * saved/restored so that protocol specific skb->cb[] data won't
379 * be lost. In any case, due to unpriviledged eBPF programs
380 * attached to sockets, we need to clear the bpf_skb_cb() area
381 * to not leak previous contents to user space.
382 */
383 BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) != BPF_SKB_CB_LEN);
384 BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) !=
385 FIELD_SIZEOF(struct qdisc_skb_cb, data));
386
387 return qdisc_skb_cb(skb)->data;
388}
389
390static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog,
391 struct sk_buff *skb)
392{
393 u8 *cb_data = bpf_skb_cb(skb);
394 u8 cb_saved[BPF_SKB_CB_LEN];
395 u32 res;
396
397 if (unlikely(prog->cb_access)) {
398 memcpy(cb_saved, cb_data, sizeof(cb_saved));
399 memset(cb_data, 0, sizeof(cb_saved));
400 }
401
402 res = BPF_PROG_RUN(prog, skb);
403
404 if (unlikely(prog->cb_access))
405 memcpy(cb_data, cb_saved, sizeof(cb_saved));
406
407 return res;
408}
409
410static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
411 struct sk_buff *skb)
412{
413 u8 *cb_data = bpf_skb_cb(skb);
414
415 if (unlikely(prog->cb_access))
416 memset(cb_data, 0, BPF_SKB_CB_LEN);
417
418 return BPF_PROG_RUN(prog, skb);
419}
420
421static inline unsigned int bpf_prog_size(unsigned int proglen)
422{
423 return max(sizeof(struct bpf_prog),
424 offsetof(struct bpf_prog, insns[proglen]));
425}
426
427static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
428{
429 /* When classic BPF programs have been loaded and the arch
430 * does not have a classic BPF JIT (anymore), they have been
431 * converted via bpf_migrate_filter() to eBPF and thus always
432 * have an unspec program type.
433 */
434 return prog->type == BPF_PROG_TYPE_UNSPEC;
435}
436
437#define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
438
439#ifdef CONFIG_DEBUG_SET_MODULE_RONX
440static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
441{
442 set_memory_ro((unsigned long)fp, fp->pages);
443}
444
445static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
446{
447 set_memory_rw((unsigned long)fp, fp->pages);
448}
449#else
450static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
451{
452}
453
454static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
455{
456}
457#endif /* CONFIG_DEBUG_SET_MODULE_RONX */
458
459int sk_filter(struct sock *sk, struct sk_buff *skb);
460
461int bpf_prog_select_runtime(struct bpf_prog *fp);
462void bpf_prog_free(struct bpf_prog *fp);
463
464struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
465struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
466 gfp_t gfp_extra_flags);
467void __bpf_prog_free(struct bpf_prog *fp);
468
469static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
470{
471 bpf_prog_unlock_ro(fp);
472 __bpf_prog_free(fp);
473}
474
475typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
476 unsigned int flen);
477
478int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
479int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
480 bpf_aux_classic_check_t trans, bool save_orig);
481void bpf_prog_destroy(struct bpf_prog *fp);
482
483int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
484int sk_attach_bpf(u32 ufd, struct sock *sk);
485int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk);
486int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk);
487int sk_detach_filter(struct sock *sk);
488int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
489 unsigned int len);
490
491bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
492void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
493
494u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
495void bpf_int_jit_compile(struct bpf_prog *fp);
496bool bpf_helper_changes_skb_data(void *func);
497
498#ifdef CONFIG_BPF_JIT
499typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
500
501struct bpf_binary_header *
502bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
503 unsigned int alignment,
504 bpf_jit_fill_hole_t bpf_fill_ill_insns);
505void bpf_jit_binary_free(struct bpf_binary_header *hdr);
506
507void bpf_jit_compile(struct bpf_prog *fp);
508void bpf_jit_free(struct bpf_prog *fp);
509
510static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
511 u32 pass, void *image)
512{
513 pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
514 proglen, pass, image, current->comm, task_pid_nr(current));
515
516 if (image)
517 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
518 16, 1, image, proglen, false);
519}
520#else
521static inline void bpf_jit_compile(struct bpf_prog *fp)
522{
523}
524
525static inline void bpf_jit_free(struct bpf_prog *fp)
526{
527 bpf_prog_unlock_free(fp);
528}
529#endif /* CONFIG_BPF_JIT */
530
531#define BPF_ANC BIT(15)
532
533static inline bool bpf_needs_clear_a(const struct sock_filter *first)
534{
535 switch (first->code) {
536 case BPF_RET | BPF_K:
537 case BPF_LD | BPF_W | BPF_LEN:
538 return false;
539
540 case BPF_LD | BPF_W | BPF_ABS:
541 case BPF_LD | BPF_H | BPF_ABS:
542 case BPF_LD | BPF_B | BPF_ABS:
543 if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
544 return true;
545 return false;
546
547 default:
548 return true;
549 }
550}
551
552static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
553{
554 BUG_ON(ftest->code & BPF_ANC);
555
556 switch (ftest->code) {
557 case BPF_LD | BPF_W | BPF_ABS:
558 case BPF_LD | BPF_H | BPF_ABS:
559 case BPF_LD | BPF_B | BPF_ABS:
560#define BPF_ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \
561 return BPF_ANC | SKF_AD_##CODE
562 switch (ftest->k) {
563 BPF_ANCILLARY(PROTOCOL);
564 BPF_ANCILLARY(PKTTYPE);
565 BPF_ANCILLARY(IFINDEX);
566 BPF_ANCILLARY(NLATTR);
567 BPF_ANCILLARY(NLATTR_NEST);
568 BPF_ANCILLARY(MARK);
569 BPF_ANCILLARY(QUEUE);
570 BPF_ANCILLARY(HATYPE);
571 BPF_ANCILLARY(RXHASH);
572 BPF_ANCILLARY(CPU);
573 BPF_ANCILLARY(ALU_XOR_X);
574 BPF_ANCILLARY(VLAN_TAG);
575 BPF_ANCILLARY(VLAN_TAG_PRESENT);
576 BPF_ANCILLARY(PAY_OFFSET);
577 BPF_ANCILLARY(RANDOM);
578 BPF_ANCILLARY(VLAN_TPID);
579 }
580 /* Fallthrough. */
581 default:
582 return ftest->code;
583 }
584}
585
586void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
587 int k, unsigned int size);
588
589static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
590 unsigned int size, void *buffer)
591{
592 if (k >= 0)
593 return skb_header_pointer(skb, k, size, buffer);
594
595 return bpf_internal_load_pointer_neg_helper(skb, k, size);
596}
597
598static inline int bpf_tell_extensions(void)
599{
600 return SKF_AD_MAX;
601}
602
603#endif /* __LINUX_FILTER_H__ */