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Merge tag 'pm+acpi-4.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[linux/fpc-iii.git] / kernel / bpf / core.c
blobc5bedc82bc1c540bf466c4d2e64f8663a974536d
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
31 #include <asm/unaligned.h>
32
33 /* Registers */
34 #define BPF_R0 regs[BPF_REG_0]
35 #define BPF_R1 regs[BPF_REG_1]
36 #define BPF_R2 regs[BPF_REG_2]
37 #define BPF_R3 regs[BPF_REG_3]
38 #define BPF_R4 regs[BPF_REG_4]
39 #define BPF_R5 regs[BPF_REG_5]
40 #define BPF_R6 regs[BPF_REG_6]
41 #define BPF_R7 regs[BPF_REG_7]
42 #define BPF_R8 regs[BPF_REG_8]
43 #define BPF_R9 regs[BPF_REG_9]
44 #define BPF_R10 regs[BPF_REG_10]
45
46 /* Named registers */
47 #define DST regs[insn->dst_reg]
48 #define SRC regs[insn->src_reg]
49 #define FP regs[BPF_REG_FP]
50 #define ARG1 regs[BPF_REG_ARG1]
51 #define CTX regs[BPF_REG_CTX]
52 #define IMM insn->imm
53
54 /* No hurry in this branch
55 *
56 * Exported for the bpf jit load helper.
57 */
58 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
59 {
60 u8 *ptr = NULL;
61
62 if (k >= SKF_NET_OFF)
63 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
64 else if (k >= SKF_LL_OFF)
65 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
66
67 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
68 return ptr;
69
70 return NULL;
71 }
72
73 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
74 {
75 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
76 gfp_extra_flags;
77 struct bpf_prog_aux *aux;
78 struct bpf_prog *fp;
79
80 size = round_up(size, PAGE_SIZE);
81 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
82 if (fp == NULL)
83 return NULL;
84
85 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
86 if (aux == NULL) {
87 vfree(fp);
88 return NULL;
89 }
90
91 fp->pages = size / PAGE_SIZE;
92 fp->aux = aux;
93
94 return fp;
95 }
96 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
97
98 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
99 gfp_t gfp_extra_flags)
100 {
101 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
102 gfp_extra_flags;
103 struct bpf_prog *fp;
104
105 BUG_ON(fp_old == NULL);
106
107 size = round_up(size, PAGE_SIZE);
108 if (size <= fp_old->pages * PAGE_SIZE)
109 return fp_old;
110
111 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
112 if (fp != NULL) {
113 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
114 fp->pages = size / PAGE_SIZE;
115
116 /* We keep fp->aux from fp_old around in the new
117 * reallocated structure.
118 */
119 fp_old->aux = NULL;
120 __bpf_prog_free(fp_old);
121 }
122
123 return fp;
124 }
125 EXPORT_SYMBOL_GPL(bpf_prog_realloc);
126
127 void __bpf_prog_free(struct bpf_prog *fp)
128 {
129 kfree(fp->aux);
130 vfree(fp);
131 }
132 EXPORT_SYMBOL_GPL(__bpf_prog_free);
133
134 #ifdef CONFIG_BPF_JIT
135 struct bpf_binary_header *
136 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
137 unsigned int alignment,
138 bpf_jit_fill_hole_t bpf_fill_ill_insns)
139 {
140 struct bpf_binary_header *hdr;
141 unsigned int size, hole, start;
142
143 /* Most of BPF filters are really small, but if some of them
144 * fill a page, allow at least 128 extra bytes to insert a
145 * random section of illegal instructions.
146 */
147 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
148 hdr = module_alloc(size);
149 if (hdr == NULL)
150 return NULL;
151
152 /* Fill space with illegal/arch-dep instructions. */
153 bpf_fill_ill_insns(hdr, size);
154
155 hdr->pages = size / PAGE_SIZE;
156 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
157 PAGE_SIZE - sizeof(*hdr));
158 start = (prandom_u32() % hole) & ~(alignment - 1);
159
160 /* Leave a random number of instructions before BPF code. */
161 *image_ptr = &hdr->image[start];
162
163 return hdr;
164 }
165
166 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
167 {
168 module_memfree(hdr);
169 }
170 #endif /* CONFIG_BPF_JIT */
171
172 /* Base function for offset calculation. Needs to go into .text section,
173 * therefore keeping it non-static as well; will also be used by JITs
174 * anyway later on, so do not let the compiler omit it.
175 */
176 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
177 {
178 return 0;
179 }
180
181 /**
182 * __bpf_prog_run - run eBPF program on a given context
183 * @ctx: is the data we are operating on
184 * @insn: is the array of eBPF instructions
185 *
186 * Decode and execute eBPF instructions.
187 */
188 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
189 {
190 u64 stack[MAX_BPF_STACK / sizeof(u64)];
191 u64 regs[MAX_BPF_REG], tmp;
192 static const void *jumptable[256] = {
193 [0 ... 255] = &&default_label,
194 /* Now overwrite non-defaults ... */
195 /* 32 bit ALU operations */
196 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
197 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
198 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
199 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
200 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
201 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
202 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X,
203 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K,
204 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
205 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
206 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
207 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
208 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
209 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
210 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
211 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
212 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
213 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
214 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
215 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
216 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
217 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
218 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
219 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
220 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
221 /* 64 bit ALU operations */
222 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
223 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
224 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
225 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
226 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
227 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
228 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
229 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
230 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
231 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
232 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
233 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
234 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
235 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
236 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
237 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
238 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
239 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
240 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
241 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
242 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
243 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
244 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
245 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
246 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
247 /* Call instruction */
248 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
249 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL,
250 /* Jumps */
251 [BPF_JMP | BPF_JA] = &&JMP_JA,
252 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
253 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
254 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
255 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
256 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
257 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
258 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
259 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
260 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
261 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
262 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
263 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
264 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
265 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
266 /* Program return */
267 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
268 /* Store instructions */
269 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
270 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
271 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
272 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
273 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
274 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
275 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
276 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
277 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
278 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
279 /* Load instructions */
280 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
281 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
282 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
283 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
284 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
285 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
286 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
287 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
288 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
289 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
290 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
291 };
292 u32 tail_call_cnt = 0;
293 void *ptr;
294 int off;
295
296 #define CONT ({ insn++; goto select_insn; })
297 #define CONT_JMP ({ insn++; goto select_insn; })
298
299 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
300 ARG1 = (u64) (unsigned long) ctx;
301
302 /* Registers used in classic BPF programs need to be reset first. */
303 regs[BPF_REG_A] = 0;
304 regs[BPF_REG_X] = 0;
305
306 select_insn:
307 goto *jumptable[insn->code];
308
309 /* ALU */
310 #define ALU(OPCODE, OP) \
311 ALU64_##OPCODE##_X: \
312 DST = DST OP SRC; \
313 CONT; \
314 ALU_##OPCODE##_X: \
315 DST = (u32) DST OP (u32) SRC; \
316 CONT; \
317 ALU64_##OPCODE##_K: \
318 DST = DST OP IMM; \
319 CONT; \
320 ALU_##OPCODE##_K: \
321 DST = (u32) DST OP (u32) IMM; \
322 CONT;
323
324 ALU(ADD, +)
325 ALU(SUB, -)
326 ALU(AND, &)
327 ALU(OR, |)
328 ALU(LSH, <<)
329 ALU(RSH, >>)
330 ALU(XOR, ^)
331 ALU(MUL, *)
332 #undef ALU
333 ALU_NEG:
334 DST = (u32) -DST;
335 CONT;
336 ALU64_NEG:
337 DST = -DST;
338 CONT;
339 ALU_MOV_X:
340 DST = (u32) SRC;
341 CONT;
342 ALU_MOV_K:
343 DST = (u32) IMM;
344 CONT;
345 ALU64_MOV_X:
346 DST = SRC;
347 CONT;
348 ALU64_MOV_K:
349 DST = IMM;
350 CONT;
351 LD_IMM_DW:
352 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
353 insn++;
354 CONT;
355 ALU64_ARSH_X:
356 (*(s64 *) &DST) >>= SRC;
357 CONT;
358 ALU64_ARSH_K:
359 (*(s64 *) &DST) >>= IMM;
360 CONT;
361 ALU64_MOD_X:
362 if (unlikely(SRC == 0))
363 return 0;
364 div64_u64_rem(DST, SRC, &tmp);
365 DST = tmp;
366 CONT;
367 ALU_MOD_X:
368 if (unlikely(SRC == 0))
369 return 0;
370 tmp = (u32) DST;
371 DST = do_div(tmp, (u32) SRC);
372 CONT;
373 ALU64_MOD_K:
374 div64_u64_rem(DST, IMM, &tmp);
375 DST = tmp;
376 CONT;
377 ALU_MOD_K:
378 tmp = (u32) DST;
379 DST = do_div(tmp, (u32) IMM);
380 CONT;
381 ALU64_DIV_X:
382 if (unlikely(SRC == 0))
383 return 0;
384 DST = div64_u64(DST, SRC);
385 CONT;
386 ALU_DIV_X:
387 if (unlikely(SRC == 0))
388 return 0;
389 tmp = (u32) DST;
390 do_div(tmp, (u32) SRC);
391 DST = (u32) tmp;
392 CONT;
393 ALU64_DIV_K:
394 DST = div64_u64(DST, IMM);
395 CONT;
396 ALU_DIV_K:
397 tmp = (u32) DST;
398 do_div(tmp, (u32) IMM);
399 DST = (u32) tmp;
400 CONT;
401 ALU_END_TO_BE:
402 switch (IMM) {
403 case 16:
404 DST = (__force u16) cpu_to_be16(DST);
405 break;
406 case 32:
407 DST = (__force u32) cpu_to_be32(DST);
408 break;
409 case 64:
410 DST = (__force u64) cpu_to_be64(DST);
411 break;
412 }
413 CONT;
414 ALU_END_TO_LE:
415 switch (IMM) {
416 case 16:
417 DST = (__force u16) cpu_to_le16(DST);
418 break;
419 case 32:
420 DST = (__force u32) cpu_to_le32(DST);
421 break;
422 case 64:
423 DST = (__force u64) cpu_to_le64(DST);
424 break;
425 }
426 CONT;
427
428 /* CALL */
429 JMP_CALL:
430 /* Function call scratches BPF_R1-BPF_R5 registers,
431 * preserves BPF_R6-BPF_R9, and stores return value
432 * into BPF_R0.
433 */
434 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
435 BPF_R4, BPF_R5);
436 CONT;
437
438 JMP_TAIL_CALL: {
439 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
440 struct bpf_array *array = container_of(map, struct bpf_array, map);
441 struct bpf_prog *prog;
442 u64 index = BPF_R3;
443
444 if (unlikely(index >= array->map.max_entries))
445 goto out;
446
447 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
448 goto out;
449
450 tail_call_cnt++;
451
452 prog = READ_ONCE(array->prog[index]);
453 if (unlikely(!prog))
454 goto out;
455
456 ARG1 = BPF_R1;
457 insn = prog->insnsi;
458 goto select_insn;
459 out:
460 CONT;
461 }
462 /* JMP */
463 JMP_JA:
464 insn += insn->off;
465 CONT;
466 JMP_JEQ_X:
467 if (DST == SRC) {
468 insn += insn->off;
469 CONT_JMP;
470 }
471 CONT;
472 JMP_JEQ_K:
473 if (DST == IMM) {
474 insn += insn->off;
475 CONT_JMP;
476 }
477 CONT;
478 JMP_JNE_X:
479 if (DST != SRC) {
480 insn += insn->off;
481 CONT_JMP;
482 }
483 CONT;
484 JMP_JNE_K:
485 if (DST != IMM) {
486 insn += insn->off;
487 CONT_JMP;
488 }
489 CONT;
490 JMP_JGT_X:
491 if (DST > SRC) {
492 insn += insn->off;
493 CONT_JMP;
494 }
495 CONT;
496 JMP_JGT_K:
497 if (DST > IMM) {
498 insn += insn->off;
499 CONT_JMP;
500 }
501 CONT;
502 JMP_JGE_X:
503 if (DST >= SRC) {
504 insn += insn->off;
505 CONT_JMP;
506 }
507 CONT;
508 JMP_JGE_K:
509 if (DST >= IMM) {
510 insn += insn->off;
511 CONT_JMP;
512 }
513 CONT;
514 JMP_JSGT_X:
515 if (((s64) DST) > ((s64) SRC)) {
516 insn += insn->off;
517 CONT_JMP;
518 }
519 CONT;
520 JMP_JSGT_K:
521 if (((s64) DST) > ((s64) IMM)) {
522 insn += insn->off;
523 CONT_JMP;
524 }
525 CONT;
526 JMP_JSGE_X:
527 if (((s64) DST) >= ((s64) SRC)) {
528 insn += insn->off;
529 CONT_JMP;
530 }
531 CONT;
532 JMP_JSGE_K:
533 if (((s64) DST) >= ((s64) IMM)) {
534 insn += insn->off;
535 CONT_JMP;
536 }
537 CONT;
538 JMP_JSET_X:
539 if (DST & SRC) {
540 insn += insn->off;
541 CONT_JMP;
542 }
543 CONT;
544 JMP_JSET_K:
545 if (DST & IMM) {
546 insn += insn->off;
547 CONT_JMP;
548 }
549 CONT;
550 JMP_EXIT:
551 return BPF_R0;
552
553 /* STX and ST and LDX*/
554 #define LDST(SIZEOP, SIZE) \
555 STX_MEM_##SIZEOP: \
556 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
557 CONT; \
558 ST_MEM_##SIZEOP: \
559 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
560 CONT; \
561 LDX_MEM_##SIZEOP: \
562 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
563 CONT;
564
565 LDST(B, u8)
566 LDST(H, u16)
567 LDST(W, u32)
568 LDST(DW, u64)
569 #undef LDST
570 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
571 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
572 (DST + insn->off));
573 CONT;
574 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
575 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
576 (DST + insn->off));
577 CONT;
578 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
579 off = IMM;
580 load_word:
581 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
582 * only appearing in the programs where ctx ==
583 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
584 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6,
585 * internal BPF verifier will check that BPF_R6 ==
586 * ctx.
587 *
588 * BPF_ABS and BPF_IND are wrappers of function calls,
589 * so they scratch BPF_R1-BPF_R5 registers, preserve
590 * BPF_R6-BPF_R9, and store return value into BPF_R0.
591 *
592 * Implicit input:
593 * ctx == skb == BPF_R6 == CTX
594 *
595 * Explicit input:
596 * SRC == any register
597 * IMM == 32-bit immediate
598 *
599 * Output:
600 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
601 */
602
603 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
604 if (likely(ptr != NULL)) {
605 BPF_R0 = get_unaligned_be32(ptr);
606 CONT;
607 }
608
609 return 0;
610 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
611 off = IMM;
612 load_half:
613 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
614 if (likely(ptr != NULL)) {
615 BPF_R0 = get_unaligned_be16(ptr);
616 CONT;
617 }
618
619 return 0;
620 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
621 off = IMM;
622 load_byte:
623 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
624 if (likely(ptr != NULL)) {
625 BPF_R0 = *(u8 *)ptr;
626 CONT;
627 }
628
629 return 0;
630 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
631 off = IMM + SRC;
632 goto load_word;
633 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
634 off = IMM + SRC;
635 goto load_half;
636 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
637 off = IMM + SRC;
638 goto load_byte;
639
640 default_label:
641 /* If we ever reach this, we have a bug somewhere. */
642 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
643 return 0;
644 }
645
646 bool bpf_prog_array_compatible(struct bpf_array *array,
647 const struct bpf_prog *fp)
648 {
649 if (!array->owner_prog_type) {
650 /* There's no owner yet where we could check for
651 * compatibility.
652 */
653 array->owner_prog_type = fp->type;
654 array->owner_jited = fp->jited;
655
656 return true;
657 }
658
659 return array->owner_prog_type == fp->type &&
660 array->owner_jited == fp->jited;
661 }
662
663 static int bpf_check_tail_call(const struct bpf_prog *fp)
664 {
665 struct bpf_prog_aux *aux = fp->aux;
666 int i;
667
668 for (i = 0; i < aux->used_map_cnt; i++) {
669 struct bpf_map *map = aux->used_maps[i];
670 struct bpf_array *array;
671
672 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
673 continue;
674
675 array = container_of(map, struct bpf_array, map);
676 if (!bpf_prog_array_compatible(array, fp))
677 return -EINVAL;
678 }
679
680 return 0;
681 }
682
683 /**
684 * bpf_prog_select_runtime - select exec runtime for BPF program
685 * @fp: bpf_prog populated with internal BPF program
686 *
687 * Try to JIT eBPF program, if JIT is not available, use interpreter.
688 * The BPF program will be executed via BPF_PROG_RUN() macro.
689 */
690 int bpf_prog_select_runtime(struct bpf_prog *fp)
691 {
692 fp->bpf_func = (void *) __bpf_prog_run;
693
694 bpf_int_jit_compile(fp);
695 bpf_prog_lock_ro(fp);
696
697 /* The tail call compatibility check can only be done at
698 * this late stage as we need to determine, if we deal
699 * with JITed or non JITed program concatenations and not
700 * all eBPF JITs might immediately support all features.
701 */
702 return bpf_check_tail_call(fp);
703 }
704 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
705
706 static void bpf_prog_free_deferred(struct work_struct *work)
707 {
708 struct bpf_prog_aux *aux;
709
710 aux = container_of(work, struct bpf_prog_aux, work);
711 bpf_jit_free(aux->prog);
712 }
713
714 /* Free internal BPF program */
715 void bpf_prog_free(struct bpf_prog *fp)
716 {
717 struct bpf_prog_aux *aux = fp->aux;
718
719 INIT_WORK(&aux->work, bpf_prog_free_deferred);
720 aux->prog = fp;
721 schedule_work(&aux->work);
722 }
723 EXPORT_SYMBOL_GPL(bpf_prog_free);
724
725 /* Weak definitions of helper functions in case we don't have bpf syscall. */
726 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
727 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
728 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
729
730 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
731 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
732 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
733 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
734 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
735 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
736 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
737 {
738 return NULL;
739 }
740
741 /* Always built-in helper functions. */
742 const struct bpf_func_proto bpf_tail_call_proto = {
743 .func = NULL,
744 .gpl_only = false,
745 .ret_type = RET_VOID,
746 .arg1_type = ARG_PTR_TO_CTX,
747 .arg2_type = ARG_CONST_MAP_PTR,
748 .arg3_type = ARG_ANYTHING,
749 };
750
751 /* For classic BPF JITs that don't implement bpf_int_jit_compile(). */
752 void __weak bpf_int_jit_compile(struct bpf_prog *prog)
753 {
754 }
755
756 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
757 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
758 */
759 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
760 int len)
761 {
762 return -EFAULT;
763 }
Linux with added FPC-III support