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

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