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Merge tag 'samsung-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene...
[deliverable/linux.git] / kernel / bpf / core.c
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 EXPORT_SYMBOL_GPL(__bpf_call_base);
181
182 /**
183 * __bpf_prog_run - run eBPF program on a given context
184 * @ctx: is the data we are operating on
185 * @insn: is the array of eBPF instructions
186 *
187 * Decode and execute eBPF instructions.
188 */
189 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
190 {
191 u64 stack[MAX_BPF_STACK / sizeof(u64)];
192 u64 regs[MAX_BPF_REG], tmp;
193 static const void *jumptable[256] = {
194 [0 ... 255] = &&default_label,
195 /* Now overwrite non-defaults ... */
196 /* 32 bit ALU operations */
197 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
198 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
199 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
200 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
201 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
202 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
203 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X,
204 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K,
205 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
206 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
207 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
208 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
209 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
210 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
211 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
212 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
213 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
214 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
215 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
216 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
217 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
218 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
219 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
220 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
221 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
222 /* 64 bit ALU operations */
223 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
224 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
225 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
226 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
227 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
228 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
229 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
230 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
231 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
232 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
233 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
234 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
235 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
236 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
237 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
238 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
239 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
240 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
241 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
242 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
243 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
244 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
245 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
246 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
247 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
248 /* Call instruction */
249 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
250 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL,
251 /* Jumps */
252 [BPF_JMP | BPF_JA] = &&JMP_JA,
253 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
254 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
255 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
256 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
257 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
258 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
259 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
260 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
261 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
262 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
263 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
264 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
265 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
266 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
267 /* Program return */
268 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
269 /* Store instructions */
270 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
271 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
272 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
273 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
274 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
275 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
276 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
277 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
278 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
279 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
280 /* Load instructions */
281 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
282 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
283 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
284 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
285 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
286 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
287 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
288 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
289 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
290 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
291 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
292 };
293 u32 tail_call_cnt = 0;
294 void *ptr;
295 int off;
296
297 #define CONT ({ insn++; goto select_insn; })
298 #define CONT_JMP ({ insn++; goto select_insn; })
299
300 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
301 ARG1 = (u64) (unsigned long) ctx;
302
303 /* Registers used in classic BPF programs need to be reset first. */
304 regs[BPF_REG_A] = 0;
305 regs[BPF_REG_X] = 0;
306
307 select_insn:
308 goto *jumptable[insn->code];
309
310 /* ALU */
311 #define ALU(OPCODE, OP) \
312 ALU64_##OPCODE##_X: \
313 DST = DST OP SRC; \
314 CONT; \
315 ALU_##OPCODE##_X: \
316 DST = (u32) DST OP (u32) SRC; \
317 CONT; \
318 ALU64_##OPCODE##_K: \
319 DST = DST OP IMM; \
320 CONT; \
321 ALU_##OPCODE##_K: \
322 DST = (u32) DST OP (u32) IMM; \
323 CONT;
324
325 ALU(ADD, +)
326 ALU(SUB, -)
327 ALU(AND, &)
328 ALU(OR, |)
329 ALU(LSH, <<)
330 ALU(RSH, >>)
331 ALU(XOR, ^)
332 ALU(MUL, *)
333 #undef ALU
334 ALU_NEG:
335 DST = (u32) -DST;
336 CONT;
337 ALU64_NEG:
338 DST = -DST;
339 CONT;
340 ALU_MOV_X:
341 DST = (u32) SRC;
342 CONT;
343 ALU_MOV_K:
344 DST = (u32) IMM;
345 CONT;
346 ALU64_MOV_X:
347 DST = SRC;
348 CONT;
349 ALU64_MOV_K:
350 DST = IMM;
351 CONT;
352 LD_IMM_DW:
353 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
354 insn++;
355 CONT;
356 ALU64_ARSH_X:
357 (*(s64 *) &DST) >>= SRC;
358 CONT;
359 ALU64_ARSH_K:
360 (*(s64 *) &DST) >>= IMM;
361 CONT;
362 ALU64_MOD_X:
363 if (unlikely(SRC == 0))
364 return 0;
365 div64_u64_rem(DST, SRC, &tmp);
366 DST = tmp;
367 CONT;
368 ALU_MOD_X:
369 if (unlikely(SRC == 0))
370 return 0;
371 tmp = (u32) DST;
372 DST = do_div(tmp, (u32) SRC);
373 CONT;
374 ALU64_MOD_K:
375 div64_u64_rem(DST, IMM, &tmp);
376 DST = tmp;
377 CONT;
378 ALU_MOD_K:
379 tmp = (u32) DST;
380 DST = do_div(tmp, (u32) IMM);
381 CONT;
382 ALU64_DIV_X:
383 if (unlikely(SRC == 0))
384 return 0;
385 DST = div64_u64(DST, SRC);
386 CONT;
387 ALU_DIV_X:
388 if (unlikely(SRC == 0))
389 return 0;
390 tmp = (u32) DST;
391 do_div(tmp, (u32) SRC);
392 DST = (u32) tmp;
393 CONT;
394 ALU64_DIV_K:
395 DST = div64_u64(DST, IMM);
396 CONT;
397 ALU_DIV_K:
398 tmp = (u32) DST;
399 do_div(tmp, (u32) IMM);
400 DST = (u32) tmp;
401 CONT;
402 ALU_END_TO_BE:
403 switch (IMM) {
404 case 16:
405 DST = (__force u16) cpu_to_be16(DST);
406 break;
407 case 32:
408 DST = (__force u32) cpu_to_be32(DST);
409 break;
410 case 64:
411 DST = (__force u64) cpu_to_be64(DST);
412 break;
413 }
414 CONT;
415 ALU_END_TO_LE:
416 switch (IMM) {
417 case 16:
418 DST = (__force u16) cpu_to_le16(DST);
419 break;
420 case 32:
421 DST = (__force u32) cpu_to_le32(DST);
422 break;
423 case 64:
424 DST = (__force u64) cpu_to_le64(DST);
425 break;
426 }
427 CONT;
428
429 /* CALL */
430 JMP_CALL:
431 /* Function call scratches BPF_R1-BPF_R5 registers,
432 * preserves BPF_R6-BPF_R9, and stores return value
433 * into BPF_R0.
434 */
435 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
436 BPF_R4, BPF_R5);
437 CONT;
438
439 JMP_TAIL_CALL: {
440 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
441 struct bpf_array *array = container_of(map, struct bpf_array, map);
442 struct bpf_prog *prog;
443 u64 index = BPF_R3;
444
445 if (unlikely(index >= array->map.max_entries))
446 goto out;
447
448 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
449 goto out;
450
451 tail_call_cnt++;
452
453 prog = READ_ONCE(array->ptrs[index]);
454 if (unlikely(!prog))
455 goto out;
456
457 /* ARG1 at this point is guaranteed to point to CTX from
458 * the verifier side due to the fact that the tail call is
459 * handeled like a helper, that is, bpf_tail_call_proto,
460 * where arg1_type is ARG_PTR_TO_CTX.
461 */
462 insn = prog->insnsi;
463 goto select_insn;
464 out:
465 CONT;
466 }
467 /* JMP */
468 JMP_JA:
469 insn += insn->off;
470 CONT;
471 JMP_JEQ_X:
472 if (DST == SRC) {
473 insn += insn->off;
474 CONT_JMP;
475 }
476 CONT;
477 JMP_JEQ_K:
478 if (DST == IMM) {
479 insn += insn->off;
480 CONT_JMP;
481 }
482 CONT;
483 JMP_JNE_X:
484 if (DST != SRC) {
485 insn += insn->off;
486 CONT_JMP;
487 }
488 CONT;
489 JMP_JNE_K:
490 if (DST != IMM) {
491 insn += insn->off;
492 CONT_JMP;
493 }
494 CONT;
495 JMP_JGT_X:
496 if (DST > SRC) {
497 insn += insn->off;
498 CONT_JMP;
499 }
500 CONT;
501 JMP_JGT_K:
502 if (DST > IMM) {
503 insn += insn->off;
504 CONT_JMP;
505 }
506 CONT;
507 JMP_JGE_X:
508 if (DST >= SRC) {
509 insn += insn->off;
510 CONT_JMP;
511 }
512 CONT;
513 JMP_JGE_K:
514 if (DST >= IMM) {
515 insn += insn->off;
516 CONT_JMP;
517 }
518 CONT;
519 JMP_JSGT_X:
520 if (((s64) DST) > ((s64) SRC)) {
521 insn += insn->off;
522 CONT_JMP;
523 }
524 CONT;
525 JMP_JSGT_K:
526 if (((s64) DST) > ((s64) IMM)) {
527 insn += insn->off;
528 CONT_JMP;
529 }
530 CONT;
531 JMP_JSGE_X:
532 if (((s64) DST) >= ((s64) SRC)) {
533 insn += insn->off;
534 CONT_JMP;
535 }
536 CONT;
537 JMP_JSGE_K:
538 if (((s64) DST) >= ((s64) IMM)) {
539 insn += insn->off;
540 CONT_JMP;
541 }
542 CONT;
543 JMP_JSET_X:
544 if (DST & SRC) {
545 insn += insn->off;
546 CONT_JMP;
547 }
548 CONT;
549 JMP_JSET_K:
550 if (DST & IMM) {
551 insn += insn->off;
552 CONT_JMP;
553 }
554 CONT;
555 JMP_EXIT:
556 return BPF_R0;
557
558 /* STX and ST and LDX*/
559 #define LDST(SIZEOP, SIZE) \
560 STX_MEM_##SIZEOP: \
561 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
562 CONT; \
563 ST_MEM_##SIZEOP: \
564 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
565 CONT; \
566 LDX_MEM_##SIZEOP: \
567 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
568 CONT;
569
570 LDST(B, u8)
571 LDST(H, u16)
572 LDST(W, u32)
573 LDST(DW, u64)
574 #undef LDST
575 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
576 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
577 (DST + insn->off));
578 CONT;
579 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
580 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
581 (DST + insn->off));
582 CONT;
583 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
584 off = IMM;
585 load_word:
586 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
587 * only appearing in the programs where ctx ==
588 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
589 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6,
590 * internal BPF verifier will check that BPF_R6 ==
591 * ctx.
592 *
593 * BPF_ABS and BPF_IND are wrappers of function calls,
594 * so they scratch BPF_R1-BPF_R5 registers, preserve
595 * BPF_R6-BPF_R9, and store return value into BPF_R0.
596 *
597 * Implicit input:
598 * ctx == skb == BPF_R6 == CTX
599 *
600 * Explicit input:
601 * SRC == any register
602 * IMM == 32-bit immediate
603 *
604 * Output:
605 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
606 */
607
608 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
609 if (likely(ptr != NULL)) {
610 BPF_R0 = get_unaligned_be32(ptr);
611 CONT;
612 }
613
614 return 0;
615 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
616 off = IMM;
617 load_half:
618 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
619 if (likely(ptr != NULL)) {
620 BPF_R0 = get_unaligned_be16(ptr);
621 CONT;
622 }
623
624 return 0;
625 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
626 off = IMM;
627 load_byte:
628 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
629 if (likely(ptr != NULL)) {
630 BPF_R0 = *(u8 *)ptr;
631 CONT;
632 }
633
634 return 0;
635 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
636 off = IMM + SRC;
637 goto load_word;
638 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
639 off = IMM + SRC;
640 goto load_half;
641 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
642 off = IMM + SRC;
643 goto load_byte;
644
645 default_label:
646 /* If we ever reach this, we have a bug somewhere. */
647 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
648 return 0;
649 }
650
651 bool bpf_prog_array_compatible(struct bpf_array *array,
652 const struct bpf_prog *fp)
653 {
654 if (!array->owner_prog_type) {
655 /* There's no owner yet where we could check for
656 * compatibility.
657 */
658 array->owner_prog_type = fp->type;
659 array->owner_jited = fp->jited;
660
661 return true;
662 }
663
664 return array->owner_prog_type == fp->type &&
665 array->owner_jited == fp->jited;
666 }
667
668 static int bpf_check_tail_call(const struct bpf_prog *fp)
669 {
670 struct bpf_prog_aux *aux = fp->aux;
671 int i;
672
673 for (i = 0; i < aux->used_map_cnt; i++) {
674 struct bpf_map *map = aux->used_maps[i];
675 struct bpf_array *array;
676
677 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
678 continue;
679
680 array = container_of(map, struct bpf_array, map);
681 if (!bpf_prog_array_compatible(array, fp))
682 return -EINVAL;
683 }
684
685 return 0;
686 }
687
688 /**
689 * bpf_prog_select_runtime - select exec runtime for BPF program
690 * @fp: bpf_prog populated with internal BPF program
691 *
692 * Try to JIT eBPF program, if JIT is not available, use interpreter.
693 * The BPF program will be executed via BPF_PROG_RUN() macro.
694 */
695 int bpf_prog_select_runtime(struct bpf_prog *fp)
696 {
697 fp->bpf_func = (void *) __bpf_prog_run;
698
699 bpf_int_jit_compile(fp);
700 bpf_prog_lock_ro(fp);
701
702 /* The tail call compatibility check can only be done at
703 * this late stage as we need to determine, if we deal
704 * with JITed or non JITed program concatenations and not
705 * all eBPF JITs might immediately support all features.
706 */
707 return bpf_check_tail_call(fp);
708 }
709 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
710
711 static void bpf_prog_free_deferred(struct work_struct *work)
712 {
713 struct bpf_prog_aux *aux;
714
715 aux = container_of(work, struct bpf_prog_aux, work);
716 bpf_jit_free(aux->prog);
717 }
718
719 /* Free internal BPF program */
720 void bpf_prog_free(struct bpf_prog *fp)
721 {
722 struct bpf_prog_aux *aux = fp->aux;
723
724 INIT_WORK(&aux->work, bpf_prog_free_deferred);
725 aux->prog = fp;
726 schedule_work(&aux->work);
727 }
728 EXPORT_SYMBOL_GPL(bpf_prog_free);
729
730 /* Weak definitions of helper functions in case we don't have bpf syscall. */
731 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
732 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
733 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
734
735 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
736 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
737 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
738 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
739 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
740 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
741 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
742 {
743 return NULL;
744 }
745
746 /* Always built-in helper functions. */
747 const struct bpf_func_proto bpf_tail_call_proto = {
748 .func = NULL,
749 .gpl_only = false,
750 .ret_type = RET_VOID,
751 .arg1_type = ARG_PTR_TO_CTX,
752 .arg2_type = ARG_CONST_MAP_PTR,
753 .arg3_type = ARG_ANYTHING,
754 };
755
756 /* For classic BPF JITs that don't implement bpf_int_jit_compile(). */
757 void __weak bpf_int_jit_compile(struct bpf_prog *prog)
758 {
759 }
760
761 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
762 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
763 */
764 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
765 int len)
766 {
767 return -EFAULT;
768 }
Linux kernel - Deliverables
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