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1/*
2 * Linux Socket Filter - Kernel level socket filtering
3 *
4 * Based on the design of the Berkeley Packet Filter. The new
5 * internal format has been designed by PLUMgrid:
6 *
7 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
8 *
9 * Authors:
10 *
11 * Jay Schulist <jschlst@samba.org>
12 * Alexei Starovoitov <ast@plumgrid.com>
13 * Daniel Borkmann <dborkman@redhat.com>
14 *
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
19 *
20 * Andi Kleen - Fix a few bad bugs and races.
21 * Kris Katterjohn - Added many additional checks in bpf_check_classic()
22 */
23
24#include <linux/filter.h>
25#include <linux/skbuff.h>
26#include <linux/vmalloc.h>
27#include <linux/random.h>
28#include <linux/moduleloader.h>
29#include <linux/bpf.h>
30#include <linux/frame.h>
31
32#include <asm/unaligned.h>
33
34/* Registers */
35#define BPF_R0 regs[BPF_REG_0]
36#define BPF_R1 regs[BPF_REG_1]
37#define BPF_R2 regs[BPF_REG_2]
38#define BPF_R3 regs[BPF_REG_3]
39#define BPF_R4 regs[BPF_REG_4]
40#define BPF_R5 regs[BPF_REG_5]
41#define BPF_R6 regs[BPF_REG_6]
42#define BPF_R7 regs[BPF_REG_7]
43#define BPF_R8 regs[BPF_REG_8]
44#define BPF_R9 regs[BPF_REG_9]
45#define BPF_R10 regs[BPF_REG_10]
46
47/* Named registers */
48#define DST regs[insn->dst_reg]
49#define SRC regs[insn->src_reg]
50#define FP regs[BPF_REG_FP]
51#define ARG1 regs[BPF_REG_ARG1]
52#define CTX regs[BPF_REG_CTX]
53#define IMM insn->imm
54
55/* No hurry in this branch
56 *
57 * Exported for the bpf jit load helper.
58 */
59void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
60{
61 u8 *ptr = NULL;
62
63 if (k >= SKF_NET_OFF)
64 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
65 else if (k >= SKF_LL_OFF)
66 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
67
68 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
69 return ptr;
70
71 return NULL;
72}
73
74struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
75{
76 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
77 gfp_extra_flags;
78 struct bpf_prog_aux *aux;
79 struct bpf_prog *fp;
80
81 size = round_up(size, PAGE_SIZE);
82 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
83 if (fp == NULL)
84 return NULL;
85
86 kmemcheck_annotate_bitfield(fp, meta);
87
88 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
89 if (aux == NULL) {
90 vfree(fp);
91 return NULL;
92 }
93
94 fp->pages = size / PAGE_SIZE;
95 fp->aux = aux;
96 fp->aux->prog = fp;
97
98 return fp;
99}
100EXPORT_SYMBOL_GPL(bpf_prog_alloc);
101
102struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
103 gfp_t gfp_extra_flags)
104{
105 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
106 gfp_extra_flags;
107 struct bpf_prog *fp;
108
109 BUG_ON(fp_old == NULL);
110
111 size = round_up(size, PAGE_SIZE);
112 if (size <= fp_old->pages * PAGE_SIZE)
113 return fp_old;
114
115 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
116 if (fp != NULL) {
117 kmemcheck_annotate_bitfield(fp, meta);
118
119 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
120 fp->pages = size / PAGE_SIZE;
121 fp->aux->prog = fp;
122
123 /* We keep fp->aux from fp_old around in the new
124 * reallocated structure.
125 */
126 fp_old->aux = NULL;
127 __bpf_prog_free(fp_old);
128 }
129
130 return fp;
131}
132EXPORT_SYMBOL_GPL(bpf_prog_realloc);
133
134void __bpf_prog_free(struct bpf_prog *fp)
135{
136 kfree(fp->aux);
137 vfree(fp);
138}
139EXPORT_SYMBOL_GPL(__bpf_prog_free);
140
141#ifdef CONFIG_BPF_JIT
142struct bpf_binary_header *
143bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
144 unsigned int alignment,
145 bpf_jit_fill_hole_t bpf_fill_ill_insns)
146{
147 struct bpf_binary_header *hdr;
148 unsigned int size, hole, start;
149
150 /* Most of BPF filters are really small, but if some of them
151 * fill a page, allow at least 128 extra bytes to insert a
152 * random section of illegal instructions.
153 */
154 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
155 hdr = module_alloc(size);
156 if (hdr == NULL)
157 return NULL;
158
159 /* Fill space with illegal/arch-dep instructions. */
160 bpf_fill_ill_insns(hdr, size);
161
162 hdr->pages = size / PAGE_SIZE;
163 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
164 PAGE_SIZE - sizeof(*hdr));
165 start = (prandom_u32() % hole) & ~(alignment - 1);
166
167 /* Leave a random number of instructions before BPF code. */
168 *image_ptr = &hdr->image[start];
169
170 return hdr;
171}
172
173void bpf_jit_binary_free(struct bpf_binary_header *hdr)
174{
175 module_memfree(hdr);
176}
177#endif /* CONFIG_BPF_JIT */
178
179/* Base function for offset calculation. Needs to go into .text section,
180 * therefore keeping it non-static as well; will also be used by JITs
181 * anyway later on, so do not let the compiler omit it.
182 */
183noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
184{
185 return 0;
186}
187EXPORT_SYMBOL_GPL(__bpf_call_base);
188
189/**
190 * __bpf_prog_run - run eBPF program on a given context
191 * @ctx: is the data we are operating on
192 * @insn: is the array of eBPF instructions
193 *
194 * Decode and execute eBPF instructions.
195 */
196static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
197{
198 u64 stack[MAX_BPF_STACK / sizeof(u64)];
199 u64 regs[MAX_BPF_REG], tmp;
200 static const void *jumptable[256] = {
201 [0 ... 255] = &&default_label,
202 /* Now overwrite non-defaults ... */
203 /* 32 bit ALU operations */
204 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
205 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
206 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
207 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
208 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
209 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
210 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X,
211 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K,
212 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
213 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
214 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
215 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
216 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
217 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
218 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
219 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
220 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
221 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
222 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
223 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
224 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
225 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
226 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
227 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
228 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
229 /* 64 bit ALU operations */
230 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
231 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
232 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
233 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
234 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
235 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
236 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
237 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
238 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
239 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
240 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
241 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
242 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
243 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
244 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
245 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
246 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
247 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
248 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
249 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
250 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
251 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
252 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
253 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
254 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
255 /* Call instruction */
256 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
257 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL,
258 /* Jumps */
259 [BPF_JMP | BPF_JA] = &&JMP_JA,
260 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
261 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
262 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
263 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
264 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
265 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
266 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
267 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
268 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
269 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
270 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
271 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
272 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
273 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
274 /* Program return */
275 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
276 /* Store instructions */
277 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
278 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
279 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
280 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
281 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
282 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
283 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
284 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
285 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
286 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
287 /* Load instructions */
288 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
289 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
290 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
291 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
292 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
293 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
294 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
295 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
296 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
297 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
298 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
299 };
300 u32 tail_call_cnt = 0;
301 void *ptr;
302 int off;
303
304#define CONT ({ insn++; goto select_insn; })
305#define CONT_JMP ({ insn++; goto select_insn; })
306
307 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
308 ARG1 = (u64) (unsigned long) ctx;
309
310select_insn:
311 goto *jumptable[insn->code];
312
313 /* ALU */
314#define ALU(OPCODE, OP) \
315 ALU64_##OPCODE##_X: \
316 DST = DST OP SRC; \
317 CONT; \
318 ALU_##OPCODE##_X: \
319 DST = (u32) DST OP (u32) SRC; \
320 CONT; \
321 ALU64_##OPCODE##_K: \
322 DST = DST OP IMM; \
323 CONT; \
324 ALU_##OPCODE##_K: \
325 DST = (u32) DST OP (u32) IMM; \
326 CONT;
327
328 ALU(ADD, +)
329 ALU(SUB, -)
330 ALU(AND, &)
331 ALU(OR, |)
332 ALU(LSH, <<)
333 ALU(RSH, >>)
334 ALU(XOR, ^)
335 ALU(MUL, *)
336#undef ALU
337 ALU_NEG:
338 DST = (u32) -DST;
339 CONT;
340 ALU64_NEG:
341 DST = -DST;
342 CONT;
343 ALU_MOV_X:
344 DST = (u32) SRC;
345 CONT;
346 ALU_MOV_K:
347 DST = (u32) IMM;
348 CONT;
349 ALU64_MOV_X:
350 DST = SRC;
351 CONT;
352 ALU64_MOV_K:
353 DST = IMM;
354 CONT;
355 LD_IMM_DW:
356 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
357 insn++;
358 CONT;
359 ALU64_ARSH_X:
360 (*(s64 *) &DST) >>= SRC;
361 CONT;
362 ALU64_ARSH_K:
363 (*(s64 *) &DST) >>= IMM;
364 CONT;
365 ALU64_MOD_X:
366 if (unlikely(SRC == 0))
367 return 0;
368 div64_u64_rem(DST, SRC, &tmp);
369 DST = tmp;
370 CONT;
371 ALU_MOD_X:
372 if (unlikely(SRC == 0))
373 return 0;
374 tmp = (u32) DST;
375 DST = do_div(tmp, (u32) SRC);
376 CONT;
377 ALU64_MOD_K:
378 div64_u64_rem(DST, IMM, &tmp);
379 DST = tmp;
380 CONT;
381 ALU_MOD_K:
382 tmp = (u32) DST;
383 DST = do_div(tmp, (u32) IMM);
384 CONT;
385 ALU64_DIV_X:
386 if (unlikely(SRC == 0))
387 return 0;
388 DST = div64_u64(DST, SRC);
389 CONT;
390 ALU_DIV_X:
391 if (unlikely(SRC == 0))
392 return 0;
393 tmp = (u32) DST;
394 do_div(tmp, (u32) SRC);
395 DST = (u32) tmp;
396 CONT;
397 ALU64_DIV_K:
398 DST = div64_u64(DST, IMM);
399 CONT;
400 ALU_DIV_K:
401 tmp = (u32) DST;
402 do_div(tmp, (u32) IMM);
403 DST = (u32) tmp;
404 CONT;
405 ALU_END_TO_BE:
406 switch (IMM) {
407 case 16:
408 DST = (__force u16) cpu_to_be16(DST);
409 break;
410 case 32:
411 DST = (__force u32) cpu_to_be32(DST);
412 break;
413 case 64:
414 DST = (__force u64) cpu_to_be64(DST);
415 break;
416 }
417 CONT;
418 ALU_END_TO_LE:
419 switch (IMM) {
420 case 16:
421 DST = (__force u16) cpu_to_le16(DST);
422 break;
423 case 32:
424 DST = (__force u32) cpu_to_le32(DST);
425 break;
426 case 64:
427 DST = (__force u64) cpu_to_le64(DST);
428 break;
429 }
430 CONT;
431
432 /* CALL */
433 JMP_CALL:
434 /* Function call scratches BPF_R1-BPF_R5 registers,
435 * preserves BPF_R6-BPF_R9, and stores return value
436 * into BPF_R0.
437 */
438 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
439 BPF_R4, BPF_R5);
440 CONT;
441
442 JMP_TAIL_CALL: {
443 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
444 struct bpf_array *array = container_of(map, struct bpf_array, map);
445 struct bpf_prog *prog;
446 u64 index = BPF_R3;
447
448 if (unlikely(index >= array->map.max_entries))
449 goto out;
450
451 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
452 goto out;
453
454 tail_call_cnt++;
455
456 prog = READ_ONCE(array->ptrs[index]);
457 if (unlikely(!prog))
458 goto out;
459
460 /* ARG1 at this point is guaranteed to point to CTX from
461 * the verifier side due to the fact that the tail call is
462 * handeled like a helper, that is, bpf_tail_call_proto,
463 * where arg1_type is ARG_PTR_TO_CTX.
464 */
465 insn = prog->insnsi;
466 goto select_insn;
467out:
468 CONT;
469 }
470 /* JMP */
471 JMP_JA:
472 insn += insn->off;
473 CONT;
474 JMP_JEQ_X:
475 if (DST == SRC) {
476 insn += insn->off;
477 CONT_JMP;
478 }
479 CONT;
480 JMP_JEQ_K:
481 if (DST == IMM) {
482 insn += insn->off;
483 CONT_JMP;
484 }
485 CONT;
486 JMP_JNE_X:
487 if (DST != SRC) {
488 insn += insn->off;
489 CONT_JMP;
490 }
491 CONT;
492 JMP_JNE_K:
493 if (DST != IMM) {
494 insn += insn->off;
495 CONT_JMP;
496 }
497 CONT;
498 JMP_JGT_X:
499 if (DST > SRC) {
500 insn += insn->off;
501 CONT_JMP;
502 }
503 CONT;
504 JMP_JGT_K:
505 if (DST > IMM) {
506 insn += insn->off;
507 CONT_JMP;
508 }
509 CONT;
510 JMP_JGE_X:
511 if (DST >= SRC) {
512 insn += insn->off;
513 CONT_JMP;
514 }
515 CONT;
516 JMP_JGE_K:
517 if (DST >= IMM) {
518 insn += insn->off;
519 CONT_JMP;
520 }
521 CONT;
522 JMP_JSGT_X:
523 if (((s64) DST) > ((s64) SRC)) {
524 insn += insn->off;
525 CONT_JMP;
526 }
527 CONT;
528 JMP_JSGT_K:
529 if (((s64) DST) > ((s64) IMM)) {
530 insn += insn->off;
531 CONT_JMP;
532 }
533 CONT;
534 JMP_JSGE_X:
535 if (((s64) DST) >= ((s64) SRC)) {
536 insn += insn->off;
537 CONT_JMP;
538 }
539 CONT;
540 JMP_JSGE_K:
541 if (((s64) DST) >= ((s64) IMM)) {
542 insn += insn->off;
543 CONT_JMP;
544 }
545 CONT;
546 JMP_JSET_X:
547 if (DST & SRC) {
548 insn += insn->off;
549 CONT_JMP;
550 }
551 CONT;
552 JMP_JSET_K:
553 if (DST & IMM) {
554 insn += insn->off;
555 CONT_JMP;
556 }
557 CONT;
558 JMP_EXIT:
559 return BPF_R0;
560
561 /* STX and ST and LDX*/
562#define LDST(SIZEOP, SIZE) \
563 STX_MEM_##SIZEOP: \
564 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
565 CONT; \
566 ST_MEM_##SIZEOP: \
567 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
568 CONT; \
569 LDX_MEM_##SIZEOP: \
570 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
571 CONT;
572
573 LDST(B, u8)
574 LDST(H, u16)
575 LDST(W, u32)
576 LDST(DW, u64)
577#undef LDST
578 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
579 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
580 (DST + insn->off));
581 CONT;
582 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
583 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
584 (DST + insn->off));
585 CONT;
586 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
587 off = IMM;
588load_word:
589 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
590 * only appearing in the programs where ctx ==
591 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
592 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6,
593 * internal BPF verifier will check that BPF_R6 ==
594 * ctx.
595 *
596 * BPF_ABS and BPF_IND are wrappers of function calls,
597 * so they scratch BPF_R1-BPF_R5 registers, preserve
598 * BPF_R6-BPF_R9, and store return value into BPF_R0.
599 *
600 * Implicit input:
601 * ctx == skb == BPF_R6 == CTX
602 *
603 * Explicit input:
604 * SRC == any register
605 * IMM == 32-bit immediate
606 *
607 * Output:
608 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
609 */
610
611 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
612 if (likely(ptr != NULL)) {
613 BPF_R0 = get_unaligned_be32(ptr);
614 CONT;
615 }
616
617 return 0;
618 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
619 off = IMM;
620load_half:
621 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
622 if (likely(ptr != NULL)) {
623 BPF_R0 = get_unaligned_be16(ptr);
624 CONT;
625 }
626
627 return 0;
628 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
629 off = IMM;
630load_byte:
631 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
632 if (likely(ptr != NULL)) {
633 BPF_R0 = *(u8 *)ptr;
634 CONT;
635 }
636
637 return 0;
638 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
639 off = IMM + SRC;
640 goto load_word;
641 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
642 off = IMM + SRC;
643 goto load_half;
644 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
645 off = IMM + SRC;
646 goto load_byte;
647
648 default_label:
649 /* If we ever reach this, we have a bug somewhere. */
650 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
651 return 0;
652}
653STACK_FRAME_NON_STANDARD(__bpf_prog_run); /* jump table */
654
655bool bpf_prog_array_compatible(struct bpf_array *array,
656 const struct bpf_prog *fp)
657{
658 if (!array->owner_prog_type) {
659 /* There's no owner yet where we could check for
660 * compatibility.
661 */
662 array->owner_prog_type = fp->type;
663 array->owner_jited = fp->jited;
664
665 return true;
666 }
667
668 return array->owner_prog_type == fp->type &&
669 array->owner_jited == fp->jited;
670}
671
672static int bpf_check_tail_call(const struct bpf_prog *fp)
673{
674 struct bpf_prog_aux *aux = fp->aux;
675 int i;
676
677 for (i = 0; i < aux->used_map_cnt; i++) {
678 struct bpf_map *map = aux->used_maps[i];
679 struct bpf_array *array;
680
681 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
682 continue;
683
684 array = container_of(map, struct bpf_array, map);
685 if (!bpf_prog_array_compatible(array, fp))
686 return -EINVAL;
687 }
688
689 return 0;
690}
691
692/**
693 * bpf_prog_select_runtime - select exec runtime for BPF program
694 * @fp: bpf_prog populated with internal BPF program
695 *
696 * Try to JIT eBPF program, if JIT is not available, use interpreter.
697 * The BPF program will be executed via BPF_PROG_RUN() macro.
698 */
699int bpf_prog_select_runtime(struct bpf_prog *fp)
700{
701 fp->bpf_func = (void *) __bpf_prog_run;
702
703 bpf_int_jit_compile(fp);
704 bpf_prog_lock_ro(fp);
705
706 /* The tail call compatibility check can only be done at
707 * this late stage as we need to determine, if we deal
708 * with JITed or non JITed program concatenations and not
709 * all eBPF JITs might immediately support all features.
710 */
711 return bpf_check_tail_call(fp);
712}
713EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
714
715static void bpf_prog_free_deferred(struct work_struct *work)
716{
717 struct bpf_prog_aux *aux;
718
719 aux = container_of(work, struct bpf_prog_aux, work);
720 bpf_jit_free(aux->prog);
721}
722
723/* Free internal BPF program */
724void bpf_prog_free(struct bpf_prog *fp)
725{
726 struct bpf_prog_aux *aux = fp->aux;
727
728 INIT_WORK(&aux->work, bpf_prog_free_deferred);
729 schedule_work(&aux->work);
730}
731EXPORT_SYMBOL_GPL(bpf_prog_free);
732
733/* RNG for unpriviledged user space with separated state from prandom_u32(). */
734static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
735
736void bpf_user_rnd_init_once(void)
737{
738 prandom_init_once(&bpf_user_rnd_state);
739}
740
741u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
742{
743 /* Should someone ever have the rather unwise idea to use some
744 * of the registers passed into this function, then note that
745 * this function is called from native eBPF and classic-to-eBPF
746 * transformations. Register assignments from both sides are
747 * different, f.e. classic always sets fn(ctx, A, X) here.
748 */
749 struct rnd_state *state;
750 u32 res;
751
752 state = &get_cpu_var(bpf_user_rnd_state);
753 res = prandom_u32_state(state);
754 put_cpu_var(state);
755
756 return res;
757}
758
759/* Weak definitions of helper functions in case we don't have bpf syscall. */
760const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
761const struct bpf_func_proto bpf_map_update_elem_proto __weak;
762const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
763
764const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
765const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
766const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
767const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
768const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
769const struct bpf_func_proto bpf_get_current_comm_proto __weak;
770const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
771{
772 return NULL;
773}
774
775/* Always built-in helper functions. */
776const struct bpf_func_proto bpf_tail_call_proto = {
777 .func = NULL,
778 .gpl_only = false,
779 .ret_type = RET_VOID,
780 .arg1_type = ARG_PTR_TO_CTX,
781 .arg2_type = ARG_CONST_MAP_PTR,
782 .arg3_type = ARG_ANYTHING,
783};
784
785/* For classic BPF JITs that don't implement bpf_int_jit_compile(). */
786void __weak bpf_int_jit_compile(struct bpf_prog *prog)
787{
788}
789
790/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
791 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
792 */
793int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
794 int len)
795{
796 return -EFAULT;
797}