bpf: verifier: add checks for BPF_ABS | BPF_IND instructions
[linux-2.6-block.git] / include / linux / filter.h
CommitLineData
1da177e4
LT
1/*
2 * Linux Socket Filter Data Structures
3 */
1da177e4
LT
4#ifndef __LINUX_FILTER_H__
5#define __LINUX_FILTER_H__
6
b954d834
DB
7#include <stdarg.h>
8
60063497 9#include <linux/atomic.h>
0c5fe1b4 10#include <linux/compat.h>
9f12fbe6 11#include <linux/skbuff.h>
b954d834
DB
12#include <linux/linkage.h>
13#include <linux/printk.h>
d45ed4a4 14#include <linux/workqueue.h>
b954d834 15
60a3b225 16#include <asm/cacheflush.h>
b954d834
DB
17
18#include <uapi/linux/filter.h>
daedfb22 19#include <uapi/linux/bpf.h>
60a3b225
DB
20
21struct sk_buff;
22struct sock;
23struct seccomp_data;
09756af4 24struct bpf_prog_aux;
792d4b5c 25
30743837
DB
26/* ArgX, context and stack frame pointer register positions. Note,
27 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
28 * calls in BPF_CALL instruction.
29 */
30#define BPF_REG_ARG1 BPF_REG_1
31#define BPF_REG_ARG2 BPF_REG_2
32#define BPF_REG_ARG3 BPF_REG_3
33#define BPF_REG_ARG4 BPF_REG_4
34#define BPF_REG_ARG5 BPF_REG_5
35#define BPF_REG_CTX BPF_REG_6
36#define BPF_REG_FP BPF_REG_10
37
38/* Additional register mappings for converted user programs. */
39#define BPF_REG_A BPF_REG_0
40#define BPF_REG_X BPF_REG_7
41#define BPF_REG_TMP BPF_REG_8
bd4cf0ed
AS
42
43/* BPF program can access up to 512 bytes of stack space. */
44#define MAX_BPF_STACK 512
45
f8f6d679
DB
46/* Helper macros for filter block array initializers. */
47
e430f34e 48/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
f8f6d679 49
e430f34e 50#define BPF_ALU64_REG(OP, DST, SRC) \
2695fb55 51 ((struct bpf_insn) { \
f8f6d679 52 .code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \
e430f34e
AS
53 .dst_reg = DST, \
54 .src_reg = SRC, \
f8f6d679
DB
55 .off = 0, \
56 .imm = 0 })
57
e430f34e 58#define BPF_ALU32_REG(OP, DST, SRC) \
2695fb55 59 ((struct bpf_insn) { \
f8f6d679 60 .code = BPF_ALU | BPF_OP(OP) | BPF_X, \
e430f34e
AS
61 .dst_reg = DST, \
62 .src_reg = SRC, \
f8f6d679
DB
63 .off = 0, \
64 .imm = 0 })
65
e430f34e 66/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
f8f6d679 67
e430f34e 68#define BPF_ALU64_IMM(OP, DST, IMM) \
2695fb55 69 ((struct bpf_insn) { \
f8f6d679 70 .code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \
e430f34e
AS
71 .dst_reg = DST, \
72 .src_reg = 0, \
f8f6d679
DB
73 .off = 0, \
74 .imm = IMM })
75
e430f34e 76#define BPF_ALU32_IMM(OP, DST, IMM) \
2695fb55 77 ((struct bpf_insn) { \
f8f6d679 78 .code = BPF_ALU | BPF_OP(OP) | BPF_K, \
e430f34e
AS
79 .dst_reg = DST, \
80 .src_reg = 0, \
f8f6d679
DB
81 .off = 0, \
82 .imm = IMM })
83
84/* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
85
e430f34e 86#define BPF_ENDIAN(TYPE, DST, LEN) \
2695fb55 87 ((struct bpf_insn) { \
f8f6d679 88 .code = BPF_ALU | BPF_END | BPF_SRC(TYPE), \
e430f34e
AS
89 .dst_reg = DST, \
90 .src_reg = 0, \
f8f6d679
DB
91 .off = 0, \
92 .imm = LEN })
93
e430f34e 94/* Short form of mov, dst_reg = src_reg */
f8f6d679 95
e430f34e 96#define BPF_MOV64_REG(DST, SRC) \
2695fb55 97 ((struct bpf_insn) { \
f8f6d679 98 .code = BPF_ALU64 | BPF_MOV | BPF_X, \
e430f34e
AS
99 .dst_reg = DST, \
100 .src_reg = SRC, \
f8f6d679
DB
101 .off = 0, \
102 .imm = 0 })
103
e430f34e 104#define BPF_MOV32_REG(DST, SRC) \
2695fb55 105 ((struct bpf_insn) { \
f8f6d679 106 .code = BPF_ALU | BPF_MOV | BPF_X, \
e430f34e
AS
107 .dst_reg = DST, \
108 .src_reg = SRC, \
f8f6d679
DB
109 .off = 0, \
110 .imm = 0 })
111
e430f34e 112/* Short form of mov, dst_reg = imm32 */
f8f6d679 113
e430f34e 114#define BPF_MOV64_IMM(DST, IMM) \
2695fb55 115 ((struct bpf_insn) { \
f8f6d679 116 .code = BPF_ALU64 | BPF_MOV | BPF_K, \
e430f34e
AS
117 .dst_reg = DST, \
118 .src_reg = 0, \
f8f6d679
DB
119 .off = 0, \
120 .imm = IMM })
121
e430f34e 122#define BPF_MOV32_IMM(DST, IMM) \
2695fb55 123 ((struct bpf_insn) { \
f8f6d679 124 .code = BPF_ALU | BPF_MOV | BPF_K, \
e430f34e
AS
125 .dst_reg = DST, \
126 .src_reg = 0, \
f8f6d679
DB
127 .off = 0, \
128 .imm = IMM })
129
02ab695b
AS
130/* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
131#define BPF_LD_IMM64(DST, IMM) \
132 BPF_LD_IMM64_RAW(DST, 0, IMM)
133
134#define BPF_LD_IMM64_RAW(DST, SRC, IMM) \
135 ((struct bpf_insn) { \
136 .code = BPF_LD | BPF_DW | BPF_IMM, \
137 .dst_reg = DST, \
138 .src_reg = SRC, \
139 .off = 0, \
140 .imm = (__u32) (IMM) }), \
141 ((struct bpf_insn) { \
142 .code = 0, /* zero is reserved opcode */ \
143 .dst_reg = 0, \
144 .src_reg = 0, \
145 .off = 0, \
146 .imm = ((__u64) (IMM)) >> 32 })
147
0246e64d
AS
148#define BPF_PSEUDO_MAP_FD 1
149
150/* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
151#define BPF_LD_MAP_FD(DST, MAP_FD) \
152 BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
153
e430f34e 154/* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
f8f6d679 155
e430f34e 156#define BPF_MOV64_RAW(TYPE, DST, SRC, IMM) \
2695fb55 157 ((struct bpf_insn) { \
f8f6d679 158 .code = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE), \
e430f34e
AS
159 .dst_reg = DST, \
160 .src_reg = SRC, \
f8f6d679
DB
161 .off = 0, \
162 .imm = IMM })
163
e430f34e 164#define BPF_MOV32_RAW(TYPE, DST, SRC, IMM) \
2695fb55 165 ((struct bpf_insn) { \
f8f6d679 166 .code = BPF_ALU | BPF_MOV | BPF_SRC(TYPE), \
e430f34e
AS
167 .dst_reg = DST, \
168 .src_reg = SRC, \
f8f6d679
DB
169 .off = 0, \
170 .imm = IMM })
171
e430f34e 172/* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
f8f6d679 173
e430f34e 174#define BPF_LD_ABS(SIZE, IMM) \
2695fb55 175 ((struct bpf_insn) { \
f8f6d679 176 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \
e430f34e
AS
177 .dst_reg = 0, \
178 .src_reg = 0, \
f8f6d679 179 .off = 0, \
e430f34e 180 .imm = IMM })
f8f6d679 181
e430f34e 182/* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
f8f6d679 183
e430f34e 184#define BPF_LD_IND(SIZE, SRC, IMM) \
2695fb55 185 ((struct bpf_insn) { \
f8f6d679 186 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_IND, \
e430f34e
AS
187 .dst_reg = 0, \
188 .src_reg = SRC, \
f8f6d679 189 .off = 0, \
e430f34e 190 .imm = IMM })
f8f6d679 191
e430f34e 192/* Memory load, dst_reg = *(uint *) (src_reg + off16) */
f8f6d679 193
e430f34e 194#define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \
2695fb55 195 ((struct bpf_insn) { \
f8f6d679 196 .code = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM, \
e430f34e
AS
197 .dst_reg = DST, \
198 .src_reg = SRC, \
f8f6d679
DB
199 .off = OFF, \
200 .imm = 0 })
201
e430f34e
AS
202/* Memory store, *(uint *) (dst_reg + off16) = src_reg */
203
204#define BPF_STX_MEM(SIZE, DST, SRC, OFF) \
2695fb55 205 ((struct bpf_insn) { \
f8f6d679 206 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM, \
e430f34e
AS
207 .dst_reg = DST, \
208 .src_reg = SRC, \
f8f6d679
DB
209 .off = OFF, \
210 .imm = 0 })
211
e430f34e
AS
212/* Memory store, *(uint *) (dst_reg + off16) = imm32 */
213
214#define BPF_ST_MEM(SIZE, DST, OFF, IMM) \
2695fb55 215 ((struct bpf_insn) { \
e430f34e
AS
216 .code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \
217 .dst_reg = DST, \
218 .src_reg = 0, \
219 .off = OFF, \
220 .imm = IMM })
221
222/* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
f8f6d679 223
e430f34e 224#define BPF_JMP_REG(OP, DST, SRC, OFF) \
2695fb55 225 ((struct bpf_insn) { \
f8f6d679 226 .code = BPF_JMP | BPF_OP(OP) | BPF_X, \
e430f34e
AS
227 .dst_reg = DST, \
228 .src_reg = SRC, \
f8f6d679
DB
229 .off = OFF, \
230 .imm = 0 })
231
e430f34e 232/* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
f8f6d679 233
e430f34e 234#define BPF_JMP_IMM(OP, DST, IMM, OFF) \
2695fb55 235 ((struct bpf_insn) { \
f8f6d679 236 .code = BPF_JMP | BPF_OP(OP) | BPF_K, \
e430f34e
AS
237 .dst_reg = DST, \
238 .src_reg = 0, \
f8f6d679
DB
239 .off = OFF, \
240 .imm = IMM })
241
242/* Function call */
243
244#define BPF_EMIT_CALL(FUNC) \
2695fb55 245 ((struct bpf_insn) { \
f8f6d679 246 .code = BPF_JMP | BPF_CALL, \
e430f34e
AS
247 .dst_reg = 0, \
248 .src_reg = 0, \
f8f6d679
DB
249 .off = 0, \
250 .imm = ((FUNC) - __bpf_call_base) })
251
252/* Raw code statement block */
253
e430f34e 254#define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \
2695fb55 255 ((struct bpf_insn) { \
f8f6d679 256 .code = CODE, \
e430f34e
AS
257 .dst_reg = DST, \
258 .src_reg = SRC, \
f8f6d679
DB
259 .off = OFF, \
260 .imm = IMM })
261
262/* Program exit */
263
264#define BPF_EXIT_INSN() \
2695fb55 265 ((struct bpf_insn) { \
f8f6d679 266 .code = BPF_JMP | BPF_EXIT, \
e430f34e
AS
267 .dst_reg = 0, \
268 .src_reg = 0, \
f8f6d679
DB
269 .off = 0, \
270 .imm = 0 })
271
272#define bytes_to_bpf_size(bytes) \
273({ \
274 int bpf_size = -EINVAL; \
275 \
276 if (bytes == sizeof(u8)) \
277 bpf_size = BPF_B; \
278 else if (bytes == sizeof(u16)) \
279 bpf_size = BPF_H; \
280 else if (bytes == sizeof(u32)) \
281 bpf_size = BPF_W; \
282 else if (bytes == sizeof(u64)) \
283 bpf_size = BPF_DW; \
284 \
285 bpf_size; \
286})
9739eef1 287
30743837 288/* Macro to invoke filter function. */
7ae457c1
AS
289#define SK_RUN_FILTER(filter, ctx) \
290 (*filter->prog->bpf_func)(ctx, filter->prog->insnsi)
bd4cf0ed 291
bd4cf0ed
AS
292#ifdef CONFIG_COMPAT
293/* A struct sock_filter is architecture independent. */
0c5fe1b4
WD
294struct compat_sock_fprog {
295 u16 len;
bd4cf0ed 296 compat_uptr_t filter; /* struct sock_filter * */
0c5fe1b4
WD
297};
298#endif
299
a3ea269b
DB
300struct sock_fprog_kern {
301 u16 len;
302 struct sock_filter *filter;
303};
304
738cbe72
DB
305struct bpf_binary_header {
306 unsigned int pages;
307 u8 image[];
308};
309
7ae457c1 310struct bpf_prog {
286aad3c
DB
311 u16 pages; /* Number of allocated pages */
312 bool jited; /* Is our filter JIT'ed? */
313 u32 len; /* Number of filter blocks */
a3ea269b 314 struct sock_fprog_kern *orig_prog; /* Original BPF program */
09756af4 315 struct bpf_prog_aux *aux; /* Auxiliary fields */
0a14842f 316 unsigned int (*bpf_func)(const struct sk_buff *skb,
2695fb55 317 const struct bpf_insn *filter);
60a3b225 318 /* Instructions for interpreter */
d45ed4a4 319 union {
bd4cf0ed 320 struct sock_filter insns[0];
2695fb55 321 struct bpf_insn insnsi[0];
d45ed4a4 322 };
b715631f
SH
323};
324
7ae457c1
AS
325struct sk_filter {
326 atomic_t refcnt;
327 struct rcu_head rcu;
328 struct bpf_prog *prog;
329};
330
331#define BPF_PROG_RUN(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi)
332
333static inline unsigned int bpf_prog_size(unsigned int proglen)
b715631f 334{
7ae457c1
AS
335 return max(sizeof(struct bpf_prog),
336 offsetof(struct bpf_prog, insns[proglen]));
b715631f
SH
337}
338
009937e7 339#define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
a3ea269b 340
60a3b225
DB
341#ifdef CONFIG_DEBUG_SET_MODULE_RONX
342static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
343{
344 set_memory_ro((unsigned long)fp, fp->pages);
345}
346
347static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
348{
349 set_memory_rw((unsigned long)fp, fp->pages);
350}
351#else
352static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
353{
354}
355
356static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
357{
358}
359#endif /* CONFIG_DEBUG_SET_MODULE_RONX */
360
fbc907f0 361int sk_filter(struct sock *sk, struct sk_buff *skb);
bd4cf0ed 362
7ae457c1
AS
363void bpf_prog_select_runtime(struct bpf_prog *fp);
364void bpf_prog_free(struct bpf_prog *fp);
bd4cf0ed 365
8fb575ca
AS
366int bpf_convert_filter(struct sock_filter *prog, int len,
367 struct bpf_insn *new_prog, int *new_len);
a3ea269b 368
60a3b225
DB
369struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
370struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
371 gfp_t gfp_extra_flags);
372void __bpf_prog_free(struct bpf_prog *fp);
373
374static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
375{
376 bpf_prog_unlock_ro(fp);
377 __bpf_prog_free(fp);
378}
379
7ae457c1
AS
380int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
381void bpf_prog_destroy(struct bpf_prog *fp);
a3ea269b 382
fbc907f0
DB
383int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
384int sk_detach_filter(struct sock *sk);
a3ea269b 385
4df95ff4 386int bpf_check_classic(const struct sock_filter *filter, unsigned int flen);
fbc907f0
DB
387int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
388 unsigned int len);
fbc907f0 389
278571ba 390bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
fbc907f0 391void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
0a14842f 392
62258278 393u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
7ae457c1 394void bpf_int_jit_compile(struct bpf_prog *fp);
62258278 395
b954d834
DB
396#ifdef CONFIG_BPF_JIT
397typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
398
399struct bpf_binary_header *
400bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
401 unsigned int alignment,
402 bpf_jit_fill_hole_t bpf_fill_ill_insns);
403void bpf_jit_binary_free(struct bpf_binary_header *hdr);
404
405void bpf_jit_compile(struct bpf_prog *fp);
406void bpf_jit_free(struct bpf_prog *fp);
407
408static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
409 u32 pass, void *image)
410{
411 pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
412 flen, proglen, pass, image);
413 if (image)
414 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
415 16, 1, image, proglen, false);
416}
417#else
418static inline void bpf_jit_compile(struct bpf_prog *fp)
419{
420}
421
422static inline void bpf_jit_free(struct bpf_prog *fp)
423{
424 bpf_prog_unlock_free(fp);
425}
426#endif /* CONFIG_BPF_JIT */
427
34805931
DB
428#define BPF_ANC BIT(15)
429
430static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
431{
432 BUG_ON(ftest->code & BPF_ANC);
433
434 switch (ftest->code) {
435 case BPF_LD | BPF_W | BPF_ABS:
436 case BPF_LD | BPF_H | BPF_ABS:
437 case BPF_LD | BPF_B | BPF_ABS:
438#define BPF_ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \
439 return BPF_ANC | SKF_AD_##CODE
440 switch (ftest->k) {
441 BPF_ANCILLARY(PROTOCOL);
442 BPF_ANCILLARY(PKTTYPE);
443 BPF_ANCILLARY(IFINDEX);
444 BPF_ANCILLARY(NLATTR);
445 BPF_ANCILLARY(NLATTR_NEST);
446 BPF_ANCILLARY(MARK);
447 BPF_ANCILLARY(QUEUE);
448 BPF_ANCILLARY(HATYPE);
449 BPF_ANCILLARY(RXHASH);
450 BPF_ANCILLARY(CPU);
451 BPF_ANCILLARY(ALU_XOR_X);
452 BPF_ANCILLARY(VLAN_TAG);
453 BPF_ANCILLARY(VLAN_TAG_PRESENT);
454 BPF_ANCILLARY(PAY_OFFSET);
455 BPF_ANCILLARY(RANDOM);
456 }
457 /* Fallthrough. */
458 default:
459 return ftest->code;
460 }
461}
462
9f12fbe6
ZSL
463void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
464 int k, unsigned int size);
465
466static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
467 unsigned int size, void *buffer)
468{
469 if (k >= 0)
470 return skb_header_pointer(skb, k, size, buffer);
471
472 return bpf_internal_load_pointer_neg_helper(skb, k, size);
473}
474
ea02f941
MS
475static inline int bpf_tell_extensions(void)
476{
37692299 477 return SKF_AD_MAX;
ea02f941
MS
478}
479
1da177e4 480#endif /* __LINUX_FILTER_H__ */