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TOMOYO Linux Cross Reference
Linux/kernel/bpf/core.c

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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  */
 59 void *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 
 74 struct 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 }
100 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
101 
102 struct 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 }
132 
133 void __bpf_prog_free(struct bpf_prog *fp)
134 {
135         kfree(fp->aux);
136         vfree(fp);
137 }
138 
139 static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn)
140 {
141         return BPF_CLASS(insn->code) == BPF_JMP  &&
142                /* Call and Exit are both special jumps with no
143                 * target inside the BPF instruction image.
144                 */
145                BPF_OP(insn->code) != BPF_CALL &&
146                BPF_OP(insn->code) != BPF_EXIT;
147 }
148 
149 static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta)
150 {
151         struct bpf_insn *insn = prog->insnsi;
152         u32 i, insn_cnt = prog->len;
153 
154         for (i = 0; i < insn_cnt; i++, insn++) {
155                 if (!bpf_is_jmp_and_has_target(insn))
156                         continue;
157 
158                 /* Adjust offset of jmps if we cross boundaries. */
159                 if (i < pos && i + insn->off + 1 > pos)
160                         insn->off += delta;
161                 else if (i > pos + delta && i + insn->off + 1 <= pos + delta)
162                         insn->off -= delta;
163         }
164 }
165 
166 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
167                                        const struct bpf_insn *patch, u32 len)
168 {
169         u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
170         struct bpf_prog *prog_adj;
171 
172         /* Since our patchlet doesn't expand the image, we're done. */
173         if (insn_delta == 0) {
174                 memcpy(prog->insnsi + off, patch, sizeof(*patch));
175                 return prog;
176         }
177 
178         insn_adj_cnt = prog->len + insn_delta;
179 
180         /* Several new instructions need to be inserted. Make room
181          * for them. Likely, there's no need for a new allocation as
182          * last page could have large enough tailroom.
183          */
184         prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
185                                     GFP_USER);
186         if (!prog_adj)
187                 return NULL;
188 
189         prog_adj->len = insn_adj_cnt;
190 
191         /* Patching happens in 3 steps:
192          *
193          * 1) Move over tail of insnsi from next instruction onwards,
194          *    so we can patch the single target insn with one or more
195          *    new ones (patching is always from 1 to n insns, n > 0).
196          * 2) Inject new instructions at the target location.
197          * 3) Adjust branch offsets if necessary.
198          */
199         insn_rest = insn_adj_cnt - off - len;
200 
201         memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
202                 sizeof(*patch) * insn_rest);
203         memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
204 
205         bpf_adj_branches(prog_adj, off, insn_delta);
206 
207         return prog_adj;
208 }
209 
210 #ifdef CONFIG_BPF_JIT
211 struct bpf_binary_header *
212 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
213                      unsigned int alignment,
214                      bpf_jit_fill_hole_t bpf_fill_ill_insns)
215 {
216         struct bpf_binary_header *hdr;
217         unsigned int size, hole, start;
218 
219         /* Most of BPF filters are really small, but if some of them
220          * fill a page, allow at least 128 extra bytes to insert a
221          * random section of illegal instructions.
222          */
223         size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
224         hdr = module_alloc(size);
225         if (hdr == NULL)
226                 return NULL;
227 
228         /* Fill space with illegal/arch-dep instructions. */
229         bpf_fill_ill_insns(hdr, size);
230 
231         hdr->pages = size / PAGE_SIZE;
232         hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
233                      PAGE_SIZE - sizeof(*hdr));
234         start = (get_random_int() % hole) & ~(alignment - 1);
235 
236         /* Leave a random number of instructions before BPF code. */
237         *image_ptr = &hdr->image[start];
238 
239         return hdr;
240 }
241 
242 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
243 {
244         module_memfree(hdr);
245 }
246 
247 int bpf_jit_harden __read_mostly;
248 
249 static int bpf_jit_blind_insn(const struct bpf_insn *from,
250                               const struct bpf_insn *aux,
251                               struct bpf_insn *to_buff)
252 {
253         struct bpf_insn *to = to_buff;
254         u32 imm_rnd = get_random_int();
255         s16 off;
256 
257         BUILD_BUG_ON(BPF_REG_AX  + 1 != MAX_BPF_JIT_REG);
258         BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
259 
260         if (from->imm == 0 &&
261             (from->code == (BPF_ALU   | BPF_MOV | BPF_K) ||
262              from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
263                 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
264                 goto out;
265         }
266 
267         switch (from->code) {
268         case BPF_ALU | BPF_ADD | BPF_K:
269         case BPF_ALU | BPF_SUB | BPF_K:
270         case BPF_ALU | BPF_AND | BPF_K:
271         case BPF_ALU | BPF_OR  | BPF_K:
272         case BPF_ALU | BPF_XOR | BPF_K:
273         case BPF_ALU | BPF_MUL | BPF_K:
274         case BPF_ALU | BPF_MOV | BPF_K:
275         case BPF_ALU | BPF_DIV | BPF_K:
276         case BPF_ALU | BPF_MOD | BPF_K:
277                 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
278                 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
279                 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
280                 break;
281 
282         case BPF_ALU64 | BPF_ADD | BPF_K:
283         case BPF_ALU64 | BPF_SUB | BPF_K:
284         case BPF_ALU64 | BPF_AND | BPF_K:
285         case BPF_ALU64 | BPF_OR  | BPF_K:
286         case BPF_ALU64 | BPF_XOR | BPF_K:
287         case BPF_ALU64 | BPF_MUL | BPF_K:
288         case BPF_ALU64 | BPF_MOV | BPF_K:
289         case BPF_ALU64 | BPF_DIV | BPF_K:
290         case BPF_ALU64 | BPF_MOD | BPF_K:
291                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
292                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
293                 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
294                 break;
295 
296         case BPF_JMP | BPF_JEQ  | BPF_K:
297         case BPF_JMP | BPF_JNE  | BPF_K:
298         case BPF_JMP | BPF_JGT  | BPF_K:
299         case BPF_JMP | BPF_JGE  | BPF_K:
300         case BPF_JMP | BPF_JSGT | BPF_K:
301         case BPF_JMP | BPF_JSGE | BPF_K:
302         case BPF_JMP | BPF_JSET | BPF_K:
303                 /* Accommodate for extra offset in case of a backjump. */
304                 off = from->off;
305                 if (off < 0)
306                         off -= 2;
307                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
308                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
309                 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
310                 break;
311 
312         case BPF_LD | BPF_ABS | BPF_W:
313         case BPF_LD | BPF_ABS | BPF_H:
314         case BPF_LD | BPF_ABS | BPF_B:
315                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
316                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
317                 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
318                 break;
319 
320         case BPF_LD | BPF_IND | BPF_W:
321         case BPF_LD | BPF_IND | BPF_H:
322         case BPF_LD | BPF_IND | BPF_B:
323                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
324                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
325                 *to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg);
326                 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
327                 break;
328 
329         case BPF_LD | BPF_IMM | BPF_DW:
330                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
331                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
332                 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
333                 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
334                 break;
335         case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
336                 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
337                 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
338                 *to++ = BPF_ALU64_REG(BPF_OR,  aux[0].dst_reg, BPF_REG_AX);
339                 break;
340 
341         case BPF_ST | BPF_MEM | BPF_DW:
342         case BPF_ST | BPF_MEM | BPF_W:
343         case BPF_ST | BPF_MEM | BPF_H:
344         case BPF_ST | BPF_MEM | BPF_B:
345                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
346                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
347                 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
348                 break;
349         }
350 out:
351         return to - to_buff;
352 }
353 
354 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
355                                               gfp_t gfp_extra_flags)
356 {
357         gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
358                           gfp_extra_flags;
359         struct bpf_prog *fp;
360 
361         fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
362         if (fp != NULL) {
363                 kmemcheck_annotate_bitfield(fp, meta);
364 
365                 /* aux->prog still points to the fp_other one, so
366                  * when promoting the clone to the real program,
367                  * this still needs to be adapted.
368                  */
369                 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
370         }
371 
372         return fp;
373 }
374 
375 static void bpf_prog_clone_free(struct bpf_prog *fp)
376 {
377         /* aux was stolen by the other clone, so we cannot free
378          * it from this path! It will be freed eventually by the
379          * other program on release.
380          *
381          * At this point, we don't need a deferred release since
382          * clone is guaranteed to not be locked.
383          */
384         fp->aux = NULL;
385         __bpf_prog_free(fp);
386 }
387 
388 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
389 {
390         /* We have to repoint aux->prog to self, as we don't
391          * know whether fp here is the clone or the original.
392          */
393         fp->aux->prog = fp;
394         bpf_prog_clone_free(fp_other);
395 }
396 
397 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
398 {
399         struct bpf_insn insn_buff[16], aux[2];
400         struct bpf_prog *clone, *tmp;
401         int insn_delta, insn_cnt;
402         struct bpf_insn *insn;
403         int i, rewritten;
404 
405         if (!bpf_jit_blinding_enabled())
406                 return prog;
407 
408         clone = bpf_prog_clone_create(prog, GFP_USER);
409         if (!clone)
410                 return ERR_PTR(-ENOMEM);
411 
412         insn_cnt = clone->len;
413         insn = clone->insnsi;
414 
415         for (i = 0; i < insn_cnt; i++, insn++) {
416                 /* We temporarily need to hold the original ld64 insn
417                  * so that we can still access the first part in the
418                  * second blinding run.
419                  */
420                 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
421                     insn[1].code == 0)
422                         memcpy(aux, insn, sizeof(aux));
423 
424                 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
425                 if (!rewritten)
426                         continue;
427 
428                 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
429                 if (!tmp) {
430                         /* Patching may have repointed aux->prog during
431                          * realloc from the original one, so we need to
432                          * fix it up here on error.
433                          */
434                         bpf_jit_prog_release_other(prog, clone);
435                         return ERR_PTR(-ENOMEM);
436                 }
437 
438                 clone = tmp;
439                 insn_delta = rewritten - 1;
440 
441                 /* Walk new program and skip insns we just inserted. */
442                 insn = clone->insnsi + i + insn_delta;
443                 insn_cnt += insn_delta;
444                 i        += insn_delta;
445         }
446 
447         return clone;
448 }
449 #endif /* CONFIG_BPF_JIT */
450 
451 /* Base function for offset calculation. Needs to go into .text section,
452  * therefore keeping it non-static as well; will also be used by JITs
453  * anyway later on, so do not let the compiler omit it.
454  */
455 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
456 {
457         return 0;
458 }
459 EXPORT_SYMBOL_GPL(__bpf_call_base);
460 
461 /**
462  *      __bpf_prog_run - run eBPF program on a given context
463  *      @ctx: is the data we are operating on
464  *      @insn: is the array of eBPF instructions
465  *
466  * Decode and execute eBPF instructions.
467  */
468 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
469 {
470         u64 stack[MAX_BPF_STACK / sizeof(u64)];
471         u64 regs[MAX_BPF_REG], tmp;
472         static const void *jumptable[256] = {
473                 [0 ... 255] = &&default_label,
474                 /* Now overwrite non-defaults ... */
475                 /* 32 bit ALU operations */
476                 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
477                 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
478                 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
479                 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
480                 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
481                 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
482                 [BPF_ALU | BPF_OR | BPF_X]  = &&ALU_OR_X,
483                 [BPF_ALU | BPF_OR | BPF_K]  = &&ALU_OR_K,
484                 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
485                 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
486                 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
487                 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
488                 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
489                 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
490                 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
491                 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
492                 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
493                 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
494                 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
495                 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
496                 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
497                 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
498                 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
499                 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
500                 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
501                 /* 64 bit ALU operations */
502                 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
503                 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
504                 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
505                 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
506                 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
507                 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
508                 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
509                 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
510                 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
511                 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
512                 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
513                 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
514                 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
515                 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
516                 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
517                 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
518                 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
519                 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
520                 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
521                 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
522                 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
523                 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
524                 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
525                 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
526                 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
527                 /* Call instruction */
528                 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
529                 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL,
530                 /* Jumps */
531                 [BPF_JMP | BPF_JA] = &&JMP_JA,
532                 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
533                 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
534                 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
535                 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
536                 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
537                 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
538                 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
539                 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
540                 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
541                 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
542                 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
543                 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
544                 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
545                 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
546                 /* Program return */
547                 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
548                 /* Store instructions */
549                 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
550                 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
551                 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
552                 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
553                 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
554                 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
555                 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
556                 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
557                 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
558                 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
559                 /* Load instructions */
560                 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
561                 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
562                 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
563                 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
564                 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
565                 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
566                 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
567                 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
568                 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
569                 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
570                 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
571         };
572         u32 tail_call_cnt = 0;
573         void *ptr;
574         int off;
575 
576 #define CONT     ({ insn++; goto select_insn; })
577 #define CONT_JMP ({ insn++; goto select_insn; })
578 
579         FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
580         ARG1 = (u64) (unsigned long) ctx;
581 
582 select_insn:
583         goto *jumptable[insn->code];
584 
585         /* ALU */
586 #define ALU(OPCODE, OP)                 \
587         ALU64_##OPCODE##_X:             \
588                 DST = DST OP SRC;       \
589                 CONT;                   \
590         ALU_##OPCODE##_X:               \
591                 DST = (u32) DST OP (u32) SRC;   \
592                 CONT;                   \
593         ALU64_##OPCODE##_K:             \
594                 DST = DST OP IMM;               \
595                 CONT;                   \
596         ALU_##OPCODE##_K:               \
597                 DST = (u32) DST OP (u32) IMM;   \
598                 CONT;
599 
600         ALU(ADD,  +)
601         ALU(SUB,  -)
602         ALU(AND,  &)
603         ALU(OR,   |)
604         ALU(LSH, <<)
605         ALU(RSH, >>)
606         ALU(XOR,  ^)
607         ALU(MUL,  *)
608 #undef ALU
609         ALU_NEG:
610                 DST = (u32) -DST;
611                 CONT;
612         ALU64_NEG:
613                 DST = -DST;
614                 CONT;
615         ALU_MOV_X:
616                 DST = (u32) SRC;
617                 CONT;
618         ALU_MOV_K:
619                 DST = (u32) IMM;
620                 CONT;
621         ALU64_MOV_X:
622                 DST = SRC;
623                 CONT;
624         ALU64_MOV_K:
625                 DST = IMM;
626                 CONT;
627         LD_IMM_DW:
628                 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
629                 insn++;
630                 CONT;
631         ALU64_ARSH_X:
632                 (*(s64 *) &DST) >>= SRC;
633                 CONT;
634         ALU64_ARSH_K:
635                 (*(s64 *) &DST) >>= IMM;
636                 CONT;
637         ALU64_MOD_X:
638                 if (unlikely(SRC == 0))
639                         return 0;
640                 div64_u64_rem(DST, SRC, &tmp);
641                 DST = tmp;
642                 CONT;
643         ALU_MOD_X:
644                 if (unlikely(SRC == 0))
645                         return 0;
646                 tmp = (u32) DST;
647                 DST = do_div(tmp, (u32) SRC);
648                 CONT;
649         ALU64_MOD_K:
650                 div64_u64_rem(DST, IMM, &tmp);
651                 DST = tmp;
652                 CONT;
653         ALU_MOD_K:
654                 tmp = (u32) DST;
655                 DST = do_div(tmp, (u32) IMM);
656                 CONT;
657         ALU64_DIV_X:
658                 if (unlikely(SRC == 0))
659                         return 0;
660                 DST = div64_u64(DST, SRC);
661                 CONT;
662         ALU_DIV_X:
663                 if (unlikely(SRC == 0))
664                         return 0;
665                 tmp = (u32) DST;
666                 do_div(tmp, (u32) SRC);
667                 DST = (u32) tmp;
668                 CONT;
669         ALU64_DIV_K:
670                 DST = div64_u64(DST, IMM);
671                 CONT;
672         ALU_DIV_K:
673                 tmp = (u32) DST;
674                 do_div(tmp, (u32) IMM);
675                 DST = (u32) tmp;
676                 CONT;
677         ALU_END_TO_BE:
678                 switch (IMM) {
679                 case 16:
680                         DST = (__force u16) cpu_to_be16(DST);
681                         break;
682                 case 32:
683                         DST = (__force u32) cpu_to_be32(DST);
684                         break;
685                 case 64:
686                         DST = (__force u64) cpu_to_be64(DST);
687                         break;
688                 }
689                 CONT;
690         ALU_END_TO_LE:
691                 switch (IMM) {
692                 case 16:
693                         DST = (__force u16) cpu_to_le16(DST);
694                         break;
695                 case 32:
696                         DST = (__force u32) cpu_to_le32(DST);
697                         break;
698                 case 64:
699                         DST = (__force u64) cpu_to_le64(DST);
700                         break;
701                 }
702                 CONT;
703 
704         /* CALL */
705         JMP_CALL:
706                 /* Function call scratches BPF_R1-BPF_R5 registers,
707                  * preserves BPF_R6-BPF_R9, and stores return value
708                  * into BPF_R0.
709                  */
710                 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
711                                                        BPF_R4, BPF_R5);
712                 CONT;
713 
714         JMP_TAIL_CALL: {
715                 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
716                 struct bpf_array *array = container_of(map, struct bpf_array, map);
717                 struct bpf_prog *prog;
718                 u64 index = BPF_R3;
719 
720                 if (unlikely(index >= array->map.max_entries))
721                         goto out;
722 
723                 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
724                         goto out;
725 
726                 tail_call_cnt++;
727 
728                 prog = READ_ONCE(array->ptrs[index]);
729                 if (unlikely(!prog))
730                         goto out;
731 
732                 /* ARG1 at this point is guaranteed to point to CTX from
733                  * the verifier side due to the fact that the tail call is
734                  * handeled like a helper, that is, bpf_tail_call_proto,
735                  * where arg1_type is ARG_PTR_TO_CTX.
736                  */
737                 insn = prog->insnsi;
738                 goto select_insn;
739 out:
740                 CONT;
741         }
742         /* JMP */
743         JMP_JA:
744                 insn += insn->off;
745                 CONT;
746         JMP_JEQ_X:
747                 if (DST == SRC) {
748                         insn += insn->off;
749                         CONT_JMP;
750                 }
751                 CONT;
752         JMP_JEQ_K:
753                 if (DST == IMM) {
754                         insn += insn->off;
755                         CONT_JMP;
756                 }
757                 CONT;
758         JMP_JNE_X:
759                 if (DST != SRC) {
760                         insn += insn->off;
761                         CONT_JMP;
762                 }
763                 CONT;
764         JMP_JNE_K:
765                 if (DST != IMM) {
766                         insn += insn->off;
767                         CONT_JMP;
768                 }
769                 CONT;
770         JMP_JGT_X:
771                 if (DST > SRC) {
772                         insn += insn->off;
773                         CONT_JMP;
774                 }
775                 CONT;
776         JMP_JGT_K:
777                 if (DST > IMM) {
778                         insn += insn->off;
779                         CONT_JMP;
780                 }
781                 CONT;
782         JMP_JGE_X:
783                 if (DST >= SRC) {
784                         insn += insn->off;
785                         CONT_JMP;
786                 }
787                 CONT;
788         JMP_JGE_K:
789                 if (DST >= IMM) {
790                         insn += insn->off;
791                         CONT_JMP;
792                 }
793                 CONT;
794         JMP_JSGT_X:
795                 if (((s64) DST) > ((s64) SRC)) {
796                         insn += insn->off;
797                         CONT_JMP;
798                 }
799                 CONT;
800         JMP_JSGT_K:
801                 if (((s64) DST) > ((s64) IMM)) {
802                         insn += insn->off;
803                         CONT_JMP;
804                 }
805                 CONT;
806         JMP_JSGE_X:
807                 if (((s64) DST) >= ((s64) SRC)) {
808                         insn += insn->off;
809                         CONT_JMP;
810                 }
811                 CONT;
812         JMP_JSGE_K:
813                 if (((s64) DST) >= ((s64) IMM)) {
814                         insn += insn->off;
815                         CONT_JMP;
816                 }
817                 CONT;
818         JMP_JSET_X:
819                 if (DST & SRC) {
820                         insn += insn->off;
821                         CONT_JMP;
822                 }
823                 CONT;
824         JMP_JSET_K:
825                 if (DST & IMM) {
826                         insn += insn->off;
827                         CONT_JMP;
828                 }
829                 CONT;
830         JMP_EXIT:
831                 return BPF_R0;
832 
833         /* STX and ST and LDX*/
834 #define LDST(SIZEOP, SIZE)                                              \
835         STX_MEM_##SIZEOP:                                               \
836                 *(SIZE *)(unsigned long) (DST + insn->off) = SRC;       \
837                 CONT;                                                   \
838         ST_MEM_##SIZEOP:                                                \
839                 *(SIZE *)(unsigned long) (DST + insn->off) = IMM;       \
840                 CONT;                                                   \
841         LDX_MEM_##SIZEOP:                                               \
842                 DST = *(SIZE *)(unsigned long) (SRC + insn->off);       \
843                 CONT;
844 
845         LDST(B,   u8)
846         LDST(H,  u16)
847         LDST(W,  u32)
848         LDST(DW, u64)
849 #undef LDST
850         STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
851                 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
852                            (DST + insn->off));
853                 CONT;
854         STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
855                 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
856                              (DST + insn->off));
857                 CONT;
858         LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
859                 off = IMM;
860 load_word:
861                 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
862                  * only appearing in the programs where ctx ==
863                  * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
864                  * == BPF_R6, bpf_convert_filter() saves it in BPF_R6,
865                  * internal BPF verifier will check that BPF_R6 ==
866                  * ctx.
867                  *
868                  * BPF_ABS and BPF_IND are wrappers of function calls,
869                  * so they scratch BPF_R1-BPF_R5 registers, preserve
870                  * BPF_R6-BPF_R9, and store return value into BPF_R0.
871                  *
872                  * Implicit input:
873                  *   ctx == skb == BPF_R6 == CTX
874                  *
875                  * Explicit input:
876                  *   SRC == any register
877                  *   IMM == 32-bit immediate
878                  *
879                  * Output:
880                  *   BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
881                  */
882 
883                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
884                 if (likely(ptr != NULL)) {
885                         BPF_R0 = get_unaligned_be32(ptr);
886                         CONT;
887                 }
888 
889                 return 0;
890         LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
891                 off = IMM;
892 load_half:
893                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
894                 if (likely(ptr != NULL)) {
895                         BPF_R0 = get_unaligned_be16(ptr);
896                         CONT;
897                 }
898 
899                 return 0;
900         LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
901                 off = IMM;
902 load_byte:
903                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
904                 if (likely(ptr != NULL)) {
905                         BPF_R0 = *(u8 *)ptr;
906                         CONT;
907                 }
908 
909                 return 0;
910         LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
911                 off = IMM + SRC;
912                 goto load_word;
913         LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
914                 off = IMM + SRC;
915                 goto load_half;
916         LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
917                 off = IMM + SRC;
918                 goto load_byte;
919 
920         default_label:
921                 /* If we ever reach this, we have a bug somewhere. */
922                 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
923                 return 0;
924 }
925 STACK_FRAME_NON_STANDARD(__bpf_prog_run); /* jump table */
926 
927 bool bpf_prog_array_compatible(struct bpf_array *array,
928                                const struct bpf_prog *fp)
929 {
930         if (!array->owner_prog_type) {
931                 /* There's no owner yet where we could check for
932                  * compatibility.
933                  */
934                 array->owner_prog_type = fp->type;
935                 array->owner_jited = fp->jited;
936 
937                 return true;
938         }
939 
940         return array->owner_prog_type == fp->type &&
941                array->owner_jited == fp->jited;
942 }
943 
944 static int bpf_check_tail_call(const struct bpf_prog *fp)
945 {
946         struct bpf_prog_aux *aux = fp->aux;
947         int i;
948 
949         for (i = 0; i < aux->used_map_cnt; i++) {
950                 struct bpf_map *map = aux->used_maps[i];
951                 struct bpf_array *array;
952 
953                 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
954                         continue;
955 
956                 array = container_of(map, struct bpf_array, map);
957                 if (!bpf_prog_array_compatible(array, fp))
958                         return -EINVAL;
959         }
960 
961         return 0;
962 }
963 
964 /**
965  *      bpf_prog_select_runtime - select exec runtime for BPF program
966  *      @fp: bpf_prog populated with internal BPF program
967  *      @err: pointer to error variable
968  *
969  * Try to JIT eBPF program, if JIT is not available, use interpreter.
970  * The BPF program will be executed via BPF_PROG_RUN() macro.
971  */
972 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
973 {
974         fp->bpf_func = (void *) __bpf_prog_run;
975 
976         /* eBPF JITs can rewrite the program in case constant
977          * blinding is active. However, in case of error during
978          * blinding, bpf_int_jit_compile() must always return a
979          * valid program, which in this case would simply not
980          * be JITed, but falls back to the interpreter.
981          */
982         fp = bpf_int_jit_compile(fp);
983         bpf_prog_lock_ro(fp);
984 
985         /* The tail call compatibility check can only be done at
986          * this late stage as we need to determine, if we deal
987          * with JITed or non JITed program concatenations and not
988          * all eBPF JITs might immediately support all features.
989          */
990         *err = bpf_check_tail_call(fp);
991 
992         return fp;
993 }
994 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
995 
996 static void bpf_prog_free_deferred(struct work_struct *work)
997 {
998         struct bpf_prog_aux *aux;
999 
1000         aux = container_of(work, struct bpf_prog_aux, work);
1001         bpf_jit_free(aux->prog);
1002 }
1003 
1004 /* Free internal BPF program */
1005 void bpf_prog_free(struct bpf_prog *fp)
1006 {
1007         struct bpf_prog_aux *aux = fp->aux;
1008 
1009         INIT_WORK(&aux->work, bpf_prog_free_deferred);
1010         schedule_work(&aux->work);
1011 }
1012 EXPORT_SYMBOL_GPL(bpf_prog_free);
1013 
1014 /* RNG for unpriviledged user space with separated state from prandom_u32(). */
1015 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
1016 
1017 void bpf_user_rnd_init_once(void)
1018 {
1019         prandom_init_once(&bpf_user_rnd_state);
1020 }
1021 
1022 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1023 {
1024         /* Should someone ever have the rather unwise idea to use some
1025          * of the registers passed into this function, then note that
1026          * this function is called from native eBPF and classic-to-eBPF
1027          * transformations. Register assignments from both sides are
1028          * different, f.e. classic always sets fn(ctx, A, X) here.
1029          */
1030         struct rnd_state *state;
1031         u32 res;
1032 
1033         state = &get_cpu_var(bpf_user_rnd_state);
1034         res = prandom_u32_state(state);
1035         put_cpu_var(state);
1036 
1037         return res;
1038 }
1039 
1040 /* Weak definitions of helper functions in case we don't have bpf syscall. */
1041 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
1042 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
1043 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
1044 
1045 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
1046 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
1047 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
1048 
1049 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
1050 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
1051 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
1052 
1053 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
1054 {
1055         return NULL;
1056 }
1057 
1058 const struct bpf_func_proto * __weak bpf_get_event_output_proto(void)
1059 {
1060         return NULL;
1061 }
1062 
1063 /* Always built-in helper functions. */
1064 const struct bpf_func_proto bpf_tail_call_proto = {
1065         .func           = NULL,
1066         .gpl_only       = false,
1067         .ret_type       = RET_VOID,
1068         .arg1_type      = ARG_PTR_TO_CTX,
1069         .arg2_type      = ARG_CONST_MAP_PTR,
1070         .arg3_type      = ARG_ANYTHING,
1071 };
1072 
1073 /* For classic BPF JITs that don't implement bpf_int_jit_compile(). */
1074 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
1075 {
1076         return prog;
1077 }
1078 
1079 bool __weak bpf_helper_changes_skb_data(void *func)
1080 {
1081         return false;
1082 }
1083 
1084 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
1085  * skb_copy_bits(), so provide a weak definition of it for NET-less config.
1086  */
1087 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
1088                          int len)
1089 {
1090         return -EFAULT;
1091 }
1092 

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