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bpf: introduce bpf_skb_vlan_push/pop() helpers
[deliverable/linux.git] / kernel / bpf / core.c
CommitLineData
f5bffecd
AS		 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.
4df95ff4 21 * Kris Katterjohn - Added many additional checks in bpf_check_classic()
f5bffecd 22 */
738cbe72 23
f5bffecd
AS		 24#include <linux/filter.h>
25#include <linux/skbuff.h>
60a3b225 26#include <linux/vmalloc.h>
738cbe72
DB		 27#include <linux/random.h>
28#include <linux/moduleloader.h>
09756af4 29#include <linux/bpf.h>
f5bffecd 30
3324b584
DB		 31#include <asm/unaligned.h>
32
f5bffecd
AS		 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 */
58void *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;
3324b584 66
f5bffecd
AS		 67 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
68 return ptr;
69
70 return NULL;
71}
72
60a3b225
DB		 73struct 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;
09756af4 77 struct bpf_prog_aux *aux;
60a3b225
DB		 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
09756af4
AS		 85 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
86 if (aux == NULL) {
60a3b225
DB		 87 vfree(fp);
88 return NULL;
89 }
90
91 fp->pages = size / PAGE_SIZE;
09756af4 92 fp->aux = aux;
60a3b225
DB		 93
94 return fp;
95}
96EXPORT_SYMBOL_GPL(bpf_prog_alloc);
97
98struct 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
09756af4 116 /* We keep fp->aux from fp_old around in the new
60a3b225
DB		 117 * reallocated structure.
118 */
09756af4 119 fp_old->aux = NULL;
60a3b225
DB		 120 __bpf_prog_free(fp_old);
121 }
122
123 return fp;
124}
125EXPORT_SYMBOL_GPL(bpf_prog_realloc);
126
127void __bpf_prog_free(struct bpf_prog *fp)
128{
09756af4 129 kfree(fp->aux);
60a3b225
DB		 130 vfree(fp);
131}
132EXPORT_SYMBOL_GPL(__bpf_prog_free);
133
b954d834 134#ifdef CONFIG_BPF_JIT
738cbe72
DB		 135struct bpf_binary_header *
136bpf_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
166void bpf_jit_binary_free(struct bpf_binary_header *hdr)
167{
be1f221c 168 module_memfree(hdr);
738cbe72 169}
b954d834 170#endif /* CONFIG_BPF_JIT */
738cbe72 171
f5bffecd
AS		 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 */
176noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
177{
178 return 0;
179}
180
181/**
7ae457c1
AS		 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
f5bffecd 185 *
7ae457c1 186 * Decode and execute eBPF instructions.
f5bffecd 187 */
7ae457c1 188static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
f5bffecd
AS		 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,
04fd61ab 249 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL,
f5bffecd
AS		 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,
02ab695b 290 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
f5bffecd 291 };
04fd61ab 292 u32 tail_call_cnt = 0;
f5bffecd
AS		 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
306select_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;
02ab695b
AS		 351 LD_IMM_DW:
352 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
353 insn++;
354 CONT;
f5bffecd
AS		 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;
876a7ae6
AS		 364 div64_u64_rem(DST, SRC, &tmp);
365 DST = tmp;
f5bffecd
AS		 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:
876a7ae6
AS		 374 div64_u64_rem(DST, IMM, &tmp);
375 DST = tmp;
f5bffecd
AS		 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;
876a7ae6 384 DST = div64_u64(DST, SRC);
f5bffecd
AS		 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:
876a7ae6 394 DST = div64_u64(DST, IMM);
f5bffecd
AS		 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
04fd61ab
AS		 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
c4675f93
DB		 456 /* ARG1 at this point is guaranteed to point to CTX from
457 * the verifier side due to the fact that the tail call is
458 * handeled like a helper, that is, bpf_tail_call_proto,
459 * where arg1_type is ARG_PTR_TO_CTX.
460 */
04fd61ab
AS		 461 insn = prog->insnsi;
462 goto select_insn;
463out:
464 CONT;
465 }
f5bffecd
AS		 466 /* JMP */
467 JMP_JA:
468 insn += insn->off;
469 CONT;
470 JMP_JEQ_X:
471 if (DST == SRC) {
472 insn += insn->off;
473 CONT_JMP;
474 }
475 CONT;
476 JMP_JEQ_K:
477 if (DST == IMM) {
478 insn += insn->off;
479 CONT_JMP;
480 }
481 CONT;
482 JMP_JNE_X:
483 if (DST != SRC) {
484 insn += insn->off;
485 CONT_JMP;
486 }
487 CONT;
488 JMP_JNE_K:
489 if (DST != IMM) {
490 insn += insn->off;
491 CONT_JMP;
492 }
493 CONT;
494 JMP_JGT_X:
495 if (DST > SRC) {
496 insn += insn->off;
497 CONT_JMP;
498 }
499 CONT;
500 JMP_JGT_K:
501 if (DST > IMM) {
502 insn += insn->off;
503 CONT_JMP;
504 }
505 CONT;
506 JMP_JGE_X:
507 if (DST >= SRC) {
508 insn += insn->off;
509 CONT_JMP;
510 }
511 CONT;
512 JMP_JGE_K:
513 if (DST >= IMM) {
514 insn += insn->off;
515 CONT_JMP;
516 }
517 CONT;
518 JMP_JSGT_X:
519 if (((s64) DST) > ((s64) SRC)) {
520 insn += insn->off;
521 CONT_JMP;
522 }
523 CONT;
524 JMP_JSGT_K:
525 if (((s64) DST) > ((s64) IMM)) {
526 insn += insn->off;
527 CONT_JMP;
528 }
529 CONT;
530 JMP_JSGE_X:
531 if (((s64) DST) >= ((s64) SRC)) {
532 insn += insn->off;
533 CONT_JMP;
534 }
535 CONT;
536 JMP_JSGE_K:
537 if (((s64) DST) >= ((s64) IMM)) {
538 insn += insn->off;
539 CONT_JMP;
540 }
541 CONT;
542 JMP_JSET_X:
543 if (DST & SRC) {
544 insn += insn->off;
545 CONT_JMP;
546 }
547 CONT;
548 JMP_JSET_K:
549 if (DST & IMM) {
550 insn += insn->off;
551 CONT_JMP;
552 }
553 CONT;
554 JMP_EXIT:
555 return BPF_R0;
556
557 /* STX and ST and LDX*/
558#define LDST(SIZEOP, SIZE) \
559 STX_MEM_##SIZEOP: \
560 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
561 CONT; \
562 ST_MEM_##SIZEOP: \
563 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
564 CONT; \
565 LDX_MEM_##SIZEOP: \
566 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
567 CONT;
568
569 LDST(B, u8)
570 LDST(H, u16)
571 LDST(W, u32)
572 LDST(DW, u64)
573#undef LDST
574 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
575 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
576 (DST + insn->off));
577 CONT;
578 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
579 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
580 (DST + insn->off));
581 CONT;
582 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
583 off = IMM;
584load_word:
585 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
586 * only appearing in the programs where ctx ==
587 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
8fb575ca 588 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6,
f5bffecd
AS		 589 * internal BPF verifier will check that BPF_R6 ==
590 * ctx.
591 *
592 * BPF_ABS and BPF_IND are wrappers of function calls,
593 * so they scratch BPF_R1-BPF_R5 registers, preserve
594 * BPF_R6-BPF_R9, and store return value into BPF_R0.
595 *
596 * Implicit input:
597 * ctx == skb == BPF_R6 == CTX
598 *
599 * Explicit input:
600 * SRC == any register
601 * IMM == 32-bit immediate
602 *
603 * Output:
604 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
605 */
606
607 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
608 if (likely(ptr != NULL)) {
609 BPF_R0 = get_unaligned_be32(ptr);
610 CONT;
611 }
612
613 return 0;
614 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
615 off = IMM;
616load_half:
617 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
618 if (likely(ptr != NULL)) {
619 BPF_R0 = get_unaligned_be16(ptr);
620 CONT;
621 }
622
623 return 0;
624 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
625 off = IMM;
626load_byte:
627 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
628 if (likely(ptr != NULL)) {
629 BPF_R0 = *(u8 *)ptr;
630 CONT;
631 }
632
633 return 0;
634 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
635 off = IMM + SRC;
636 goto load_word;
637 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
638 off = IMM + SRC;
639 goto load_half;
640 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
641 off = IMM + SRC;
642 goto load_byte;
643
644 default_label:
645 /* If we ever reach this, we have a bug somewhere. */
646 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
647 return 0;
648}
649
3324b584
DB		 650bool bpf_prog_array_compatible(struct bpf_array *array,
651 const struct bpf_prog *fp)
04fd61ab 652{
3324b584
DB		 653 if (!array->owner_prog_type) {
654 /* There's no owner yet where we could check for
655 * compatibility.
656 */
04fd61ab
AS		 657 array->owner_prog_type = fp->type;
658 array->owner_jited = fp->jited;
3324b584
DB		 659
660 return true;
04fd61ab 661 }
3324b584
DB		 662
663 return array->owner_prog_type == fp->type &&
664 array->owner_jited == fp->jited;
04fd61ab
AS		 665}
666
3324b584 667static int bpf_check_tail_call(const struct bpf_prog *fp)
04fd61ab
AS		 668{
669 struct bpf_prog_aux *aux = fp->aux;
670 int i;
671
672 for (i = 0; i < aux->used_map_cnt; i++) {
3324b584 673 struct bpf_map *map = aux->used_maps[i];
04fd61ab 674 struct bpf_array *array;
04fd61ab 675
04fd61ab
AS		 676 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
677 continue;
3324b584 678
04fd61ab
AS		 679 array = container_of(map, struct bpf_array, map);
680 if (!bpf_prog_array_compatible(array, fp))
681 return -EINVAL;
682 }
683
684 return 0;
685}
686
f5bffecd 687/**
3324b584 688 * bpf_prog_select_runtime - select exec runtime for BPF program
7ae457c1 689 * @fp: bpf_prog populated with internal BPF program
f5bffecd 690 *
3324b584
DB		 691 * Try to JIT eBPF program, if JIT is not available, use interpreter.
692 * The BPF program will be executed via BPF_PROG_RUN() macro.
f5bffecd 693 */
04fd61ab 694int bpf_prog_select_runtime(struct bpf_prog *fp)
f5bffecd 695{
7ae457c1 696 fp->bpf_func = (void *) __bpf_prog_run;
f5bffecd 697
f5bffecd 698 bpf_int_jit_compile(fp);
60a3b225 699 bpf_prog_lock_ro(fp);
04fd61ab 700
3324b584
DB		 701 /* The tail call compatibility check can only be done at
702 * this late stage as we need to determine, if we deal
703 * with JITed or non JITed program concatenations and not
704 * all eBPF JITs might immediately support all features.
705 */
706 return bpf_check_tail_call(fp);
f5bffecd 707}
7ae457c1 708EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
f5bffecd 709
60a3b225
DB		 710static void bpf_prog_free_deferred(struct work_struct *work)
711{
09756af4 712 struct bpf_prog_aux *aux;
60a3b225 713
09756af4
AS		 714 aux = container_of(work, struct bpf_prog_aux, work);
715 bpf_jit_free(aux->prog);
60a3b225
DB		 716}
717
718/* Free internal BPF program */
7ae457c1 719void bpf_prog_free(struct bpf_prog *fp)
f5bffecd 720{
09756af4 721 struct bpf_prog_aux *aux = fp->aux;
60a3b225 722
09756af4
AS		 723 INIT_WORK(&aux->work, bpf_prog_free_deferred);
724 aux->prog = fp;
725 schedule_work(&aux->work);
f5bffecd 726}
7ae457c1 727EXPORT_SYMBOL_GPL(bpf_prog_free);
f89b7755 728
3ba67dab
DB		 729/* Weak definitions of helper functions in case we don't have bpf syscall. */
730const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
731const struct bpf_func_proto bpf_map_update_elem_proto __weak;
732const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
733
03e69b50 734const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
c04167ce 735const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
17ca8cbf 736const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
ffeedafb
AS		 737const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
738const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
739const struct bpf_func_proto bpf_get_current_comm_proto __weak;
0756ea3e
AS		 740const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
741{
742 return NULL;
743}
03e69b50 744
3324b584
DB		 745/* Always built-in helper functions. */
746const struct bpf_func_proto bpf_tail_call_proto = {
747 .func = NULL,
748 .gpl_only = false,
749 .ret_type = RET_VOID,
750 .arg1_type = ARG_PTR_TO_CTX,
751 .arg2_type = ARG_CONST_MAP_PTR,
752 .arg3_type = ARG_ANYTHING,
753};
754
755/* For classic BPF JITs that don't implement bpf_int_jit_compile(). */
756void __weak bpf_int_jit_compile(struct bpf_prog *prog)
757{
758}
759
f89b7755
AS		 760/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
761 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
762 */
763int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
764 int len)
765{
766 return -EFAULT;
767}
Linux kernel - Deliverables
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