2 * Linux Socket Filter - Kernel level socket filtering
4 * Based on the design of the Berkeley Packet Filter. The new
5 * internal format has been designed by PLUMgrid:
7 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
11 * Jay Schulist <jschlst@samba.org>
12 * Alexei Starovoitov <ast@plumgrid.com>
13 * Daniel Borkmann <dborkman@redhat.com>
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.
20 * Andi Kleen - Fix a few bad bugs and races.
21 * Kris Katterjohn - Added many additional checks in bpf_check_classic()
24 #include <linux/module.h>
25 #include <linux/types.h>
27 #include <linux/fcntl.h>
28 #include <linux/socket.h>
30 #include <linux/inet.h>
31 #include <linux/netdevice.h>
32 #include <linux/if_packet.h>
33 #include <linux/gfp.h>
35 #include <net/protocol.h>
36 #include <net/netlink.h>
37 #include <linux/skbuff.h>
39 #include <linux/errno.h>
40 #include <linux/timer.h>
41 #include <asm/uaccess.h>
42 #include <asm/unaligned.h>
43 #include <linux/filter.h>
44 #include <linux/ratelimit.h>
45 #include <linux/seccomp.h>
46 #include <linux/if_vlan.h>
47 #include <linux/bpf.h>
50 * sk_filter - run a packet through a socket filter
51 * @sk: sock associated with &sk_buff
52 * @skb: buffer to filter
54 * Run the filter code and then cut skb->data to correct size returned by
55 * SK_RUN_FILTER. If pkt_len is 0 we toss packet. If skb->len is smaller
56 * than pkt_len we keep whole skb->data. This is the socket level
57 * wrapper to SK_RUN_FILTER. It returns 0 if the packet should
58 * be accepted or -EPERM if the packet should be tossed.
61 int sk_filter(struct sock
*sk
, struct sk_buff
*skb
)
64 struct sk_filter
*filter
;
67 * If the skb was allocated from pfmemalloc reserves, only
68 * allow SOCK_MEMALLOC sockets to use it as this socket is
71 if (skb_pfmemalloc(skb
) && !sock_flag(sk
, SOCK_MEMALLOC
))
74 err
= security_sock_rcv_skb(sk
, skb
);
79 filter
= rcu_dereference(sk
->sk_filter
);
81 unsigned int pkt_len
= SK_RUN_FILTER(filter
, skb
);
83 err
= pkt_len
? pskb_trim(skb
, pkt_len
) : -EPERM
;
89 EXPORT_SYMBOL(sk_filter
);
91 static u64
__skb_get_pay_offset(u64 ctx
, u64 a
, u64 x
, u64 r4
, u64 r5
)
93 return skb_get_poff((struct sk_buff
*)(unsigned long) ctx
);
96 static u64
__skb_get_nlattr(u64 ctx
, u64 a
, u64 x
, u64 r4
, u64 r5
)
98 struct sk_buff
*skb
= (struct sk_buff
*)(unsigned long) ctx
;
101 if (skb_is_nonlinear(skb
))
104 if (skb
->len
< sizeof(struct nlattr
))
107 if (a
> skb
->len
- sizeof(struct nlattr
))
110 nla
= nla_find((struct nlattr
*) &skb
->data
[a
], skb
->len
- a
, x
);
112 return (void *) nla
- (void *) skb
->data
;
117 static u64
__skb_get_nlattr_nest(u64 ctx
, u64 a
, u64 x
, u64 r4
, u64 r5
)
119 struct sk_buff
*skb
= (struct sk_buff
*)(unsigned long) ctx
;
122 if (skb_is_nonlinear(skb
))
125 if (skb
->len
< sizeof(struct nlattr
))
128 if (a
> skb
->len
- sizeof(struct nlattr
))
131 nla
= (struct nlattr
*) &skb
->data
[a
];
132 if (nla
->nla_len
> skb
->len
- a
)
135 nla
= nla_find_nested(nla
, x
);
137 return (void *) nla
- (void *) skb
->data
;
142 static u64
__get_raw_cpu_id(u64 ctx
, u64 a
, u64 x
, u64 r4
, u64 r5
)
144 return raw_smp_processor_id();
147 /* note that this only generates 32-bit random numbers */
148 static u64
__get_random_u32(u64 ctx
, u64 a
, u64 x
, u64 r4
, u64 r5
)
150 return prandom_u32();
153 static u32
convert_skb_access(int skb_field
, int dst_reg
, int src_reg
,
154 struct bpf_insn
*insn_buf
)
156 struct bpf_insn
*insn
= insn_buf
;
160 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, mark
) != 4);
162 *insn
++ = BPF_LDX_MEM(BPF_W
, dst_reg
, src_reg
,
163 offsetof(struct sk_buff
, mark
));
167 *insn
++ = BPF_LDX_MEM(BPF_B
, dst_reg
, src_reg
, PKT_TYPE_OFFSET());
168 *insn
++ = BPF_ALU32_IMM(BPF_AND
, dst_reg
, PKT_TYPE_MAX
);
169 #ifdef __BIG_ENDIAN_BITFIELD
170 *insn
++ = BPF_ALU32_IMM(BPF_RSH
, dst_reg
, 5);
175 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, queue_mapping
) != 2);
177 *insn
++ = BPF_LDX_MEM(BPF_H
, dst_reg
, src_reg
,
178 offsetof(struct sk_buff
, queue_mapping
));
181 case SKF_AD_VLAN_TAG
:
182 case SKF_AD_VLAN_TAG_PRESENT
:
183 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, vlan_tci
) != 2);
184 BUILD_BUG_ON(VLAN_TAG_PRESENT
!= 0x1000);
186 /* dst_reg = *(u16 *) (src_reg + offsetof(vlan_tci)) */
187 *insn
++ = BPF_LDX_MEM(BPF_H
, dst_reg
, src_reg
,
188 offsetof(struct sk_buff
, vlan_tci
));
189 if (skb_field
== SKF_AD_VLAN_TAG
) {
190 *insn
++ = BPF_ALU32_IMM(BPF_AND
, dst_reg
,
194 *insn
++ = BPF_ALU32_IMM(BPF_RSH
, dst_reg
, 12);
196 *insn
++ = BPF_ALU32_IMM(BPF_AND
, dst_reg
, 1);
201 return insn
- insn_buf
;
204 static bool convert_bpf_extensions(struct sock_filter
*fp
,
205 struct bpf_insn
**insnp
)
207 struct bpf_insn
*insn
= *insnp
;
211 case SKF_AD_OFF
+ SKF_AD_PROTOCOL
:
212 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, protocol
) != 2);
214 /* A = *(u16 *) (CTX + offsetof(protocol)) */
215 *insn
++ = BPF_LDX_MEM(BPF_H
, BPF_REG_A
, BPF_REG_CTX
,
216 offsetof(struct sk_buff
, protocol
));
217 /* A = ntohs(A) [emitting a nop or swap16] */
218 *insn
= BPF_ENDIAN(BPF_FROM_BE
, BPF_REG_A
, 16);
221 case SKF_AD_OFF
+ SKF_AD_PKTTYPE
:
222 cnt
= convert_skb_access(SKF_AD_PKTTYPE
, BPF_REG_A
, BPF_REG_CTX
, insn
);
226 case SKF_AD_OFF
+ SKF_AD_IFINDEX
:
227 case SKF_AD_OFF
+ SKF_AD_HATYPE
:
228 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device
, ifindex
) != 4);
229 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device
, type
) != 2);
230 BUILD_BUG_ON(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff
, dev
)) < 0);
232 *insn
++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff
, dev
)),
233 BPF_REG_TMP
, BPF_REG_CTX
,
234 offsetof(struct sk_buff
, dev
));
235 /* if (tmp != 0) goto pc + 1 */
236 *insn
++ = BPF_JMP_IMM(BPF_JNE
, BPF_REG_TMP
, 0, 1);
237 *insn
++ = BPF_EXIT_INSN();
238 if (fp
->k
== SKF_AD_OFF
+ SKF_AD_IFINDEX
)
239 *insn
= BPF_LDX_MEM(BPF_W
, BPF_REG_A
, BPF_REG_TMP
,
240 offsetof(struct net_device
, ifindex
));
242 *insn
= BPF_LDX_MEM(BPF_H
, BPF_REG_A
, BPF_REG_TMP
,
243 offsetof(struct net_device
, type
));
246 case SKF_AD_OFF
+ SKF_AD_MARK
:
247 cnt
= convert_skb_access(SKF_AD_MARK
, BPF_REG_A
, BPF_REG_CTX
, insn
);
251 case SKF_AD_OFF
+ SKF_AD_RXHASH
:
252 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, hash
) != 4);
254 *insn
= BPF_LDX_MEM(BPF_W
, BPF_REG_A
, BPF_REG_CTX
,
255 offsetof(struct sk_buff
, hash
));
258 case SKF_AD_OFF
+ SKF_AD_QUEUE
:
259 cnt
= convert_skb_access(SKF_AD_QUEUE
, BPF_REG_A
, BPF_REG_CTX
, insn
);
263 case SKF_AD_OFF
+ SKF_AD_VLAN_TAG
:
264 cnt
= convert_skb_access(SKF_AD_VLAN_TAG
,
265 BPF_REG_A
, BPF_REG_CTX
, insn
);
269 case SKF_AD_OFF
+ SKF_AD_VLAN_TAG_PRESENT
:
270 cnt
= convert_skb_access(SKF_AD_VLAN_TAG_PRESENT
,
271 BPF_REG_A
, BPF_REG_CTX
, insn
);
275 case SKF_AD_OFF
+ SKF_AD_VLAN_TPID
:
276 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, vlan_proto
) != 2);
278 /* A = *(u16 *) (CTX + offsetof(vlan_proto)) */
279 *insn
++ = BPF_LDX_MEM(BPF_H
, BPF_REG_A
, BPF_REG_CTX
,
280 offsetof(struct sk_buff
, vlan_proto
));
281 /* A = ntohs(A) [emitting a nop or swap16] */
282 *insn
= BPF_ENDIAN(BPF_FROM_BE
, BPF_REG_A
, 16);
285 case SKF_AD_OFF
+ SKF_AD_PAY_OFFSET
:
286 case SKF_AD_OFF
+ SKF_AD_NLATTR
:
287 case SKF_AD_OFF
+ SKF_AD_NLATTR_NEST
:
288 case SKF_AD_OFF
+ SKF_AD_CPU
:
289 case SKF_AD_OFF
+ SKF_AD_RANDOM
:
291 *insn
++ = BPF_MOV64_REG(BPF_REG_ARG1
, BPF_REG_CTX
);
293 *insn
++ = BPF_MOV64_REG(BPF_REG_ARG2
, BPF_REG_A
);
295 *insn
++ = BPF_MOV64_REG(BPF_REG_ARG3
, BPF_REG_X
);
296 /* Emit call(arg1=CTX, arg2=A, arg3=X) */
298 case SKF_AD_OFF
+ SKF_AD_PAY_OFFSET
:
299 *insn
= BPF_EMIT_CALL(__skb_get_pay_offset
);
301 case SKF_AD_OFF
+ SKF_AD_NLATTR
:
302 *insn
= BPF_EMIT_CALL(__skb_get_nlattr
);
304 case SKF_AD_OFF
+ SKF_AD_NLATTR_NEST
:
305 *insn
= BPF_EMIT_CALL(__skb_get_nlattr_nest
);
307 case SKF_AD_OFF
+ SKF_AD_CPU
:
308 *insn
= BPF_EMIT_CALL(__get_raw_cpu_id
);
310 case SKF_AD_OFF
+ SKF_AD_RANDOM
:
311 *insn
= BPF_EMIT_CALL(__get_random_u32
);
316 case SKF_AD_OFF
+ SKF_AD_ALU_XOR_X
:
318 *insn
= BPF_ALU32_REG(BPF_XOR
, BPF_REG_A
, BPF_REG_X
);
322 /* This is just a dummy call to avoid letting the compiler
323 * evict __bpf_call_base() as an optimization. Placed here
324 * where no-one bothers.
326 BUG_ON(__bpf_call_base(0, 0, 0, 0, 0) != 0);
335 * bpf_convert_filter - convert filter program
336 * @prog: the user passed filter program
337 * @len: the length of the user passed filter program
338 * @new_prog: buffer where converted program will be stored
339 * @new_len: pointer to store length of converted program
341 * Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style.
342 * Conversion workflow:
344 * 1) First pass for calculating the new program length:
345 * bpf_convert_filter(old_prog, old_len, NULL, &new_len)
347 * 2) 2nd pass to remap in two passes: 1st pass finds new
348 * jump offsets, 2nd pass remapping:
349 * new_prog = kmalloc(sizeof(struct bpf_insn) * new_len);
350 * bpf_convert_filter(old_prog, old_len, new_prog, &new_len);
352 * User BPF's register A is mapped to our BPF register 6, user BPF
353 * register X is mapped to BPF register 7; frame pointer is always
354 * register 10; Context 'void *ctx' is stored in register 1, that is,
355 * for socket filters: ctx == 'struct sk_buff *', for seccomp:
356 * ctx == 'struct seccomp_data *'.
358 int bpf_convert_filter(struct sock_filter
*prog
, int len
,
359 struct bpf_insn
*new_prog
, int *new_len
)
361 int new_flen
= 0, pass
= 0, target
, i
;
362 struct bpf_insn
*new_insn
;
363 struct sock_filter
*fp
;
367 BUILD_BUG_ON(BPF_MEMWORDS
* sizeof(u32
) > MAX_BPF_STACK
);
368 BUILD_BUG_ON(BPF_REG_FP
+ 1 != MAX_BPF_REG
);
370 if (len
<= 0 || len
> BPF_MAXINSNS
)
374 addrs
= kcalloc(len
, sizeof(*addrs
), GFP_KERNEL
);
384 *new_insn
= BPF_MOV64_REG(BPF_REG_CTX
, BPF_REG_ARG1
);
387 for (i
= 0; i
< len
; fp
++, i
++) {
388 struct bpf_insn tmp_insns
[6] = { };
389 struct bpf_insn
*insn
= tmp_insns
;
392 addrs
[i
] = new_insn
- new_prog
;
395 /* All arithmetic insns and skb loads map as-is. */
396 case BPF_ALU
| BPF_ADD
| BPF_X
:
397 case BPF_ALU
| BPF_ADD
| BPF_K
:
398 case BPF_ALU
| BPF_SUB
| BPF_X
:
399 case BPF_ALU
| BPF_SUB
| BPF_K
:
400 case BPF_ALU
| BPF_AND
| BPF_X
:
401 case BPF_ALU
| BPF_AND
| BPF_K
:
402 case BPF_ALU
| BPF_OR
| BPF_X
:
403 case BPF_ALU
| BPF_OR
| BPF_K
:
404 case BPF_ALU
| BPF_LSH
| BPF_X
:
405 case BPF_ALU
| BPF_LSH
| BPF_K
:
406 case BPF_ALU
| BPF_RSH
| BPF_X
:
407 case BPF_ALU
| BPF_RSH
| BPF_K
:
408 case BPF_ALU
| BPF_XOR
| BPF_X
:
409 case BPF_ALU
| BPF_XOR
| BPF_K
:
410 case BPF_ALU
| BPF_MUL
| BPF_X
:
411 case BPF_ALU
| BPF_MUL
| BPF_K
:
412 case BPF_ALU
| BPF_DIV
| BPF_X
:
413 case BPF_ALU
| BPF_DIV
| BPF_K
:
414 case BPF_ALU
| BPF_MOD
| BPF_X
:
415 case BPF_ALU
| BPF_MOD
| BPF_K
:
416 case BPF_ALU
| BPF_NEG
:
417 case BPF_LD
| BPF_ABS
| BPF_W
:
418 case BPF_LD
| BPF_ABS
| BPF_H
:
419 case BPF_LD
| BPF_ABS
| BPF_B
:
420 case BPF_LD
| BPF_IND
| BPF_W
:
421 case BPF_LD
| BPF_IND
| BPF_H
:
422 case BPF_LD
| BPF_IND
| BPF_B
:
423 /* Check for overloaded BPF extension and
424 * directly convert it if found, otherwise
425 * just move on with mapping.
427 if (BPF_CLASS(fp
->code
) == BPF_LD
&&
428 BPF_MODE(fp
->code
) == BPF_ABS
&&
429 convert_bpf_extensions(fp
, &insn
))
432 *insn
= BPF_RAW_INSN(fp
->code
, BPF_REG_A
, BPF_REG_X
, 0, fp
->k
);
435 /* Jump transformation cannot use BPF block macros
436 * everywhere as offset calculation and target updates
437 * require a bit more work than the rest, i.e. jump
438 * opcodes map as-is, but offsets need adjustment.
441 #define BPF_EMIT_JMP \
443 if (target >= len || target < 0) \
445 insn->off = addrs ? addrs[target] - addrs[i] - 1 : 0; \
446 /* Adjust pc relative offset for 2nd or 3rd insn. */ \
447 insn->off -= insn - tmp_insns; \
450 case BPF_JMP
| BPF_JA
:
451 target
= i
+ fp
->k
+ 1;
452 insn
->code
= fp
->code
;
456 case BPF_JMP
| BPF_JEQ
| BPF_K
:
457 case BPF_JMP
| BPF_JEQ
| BPF_X
:
458 case BPF_JMP
| BPF_JSET
| BPF_K
:
459 case BPF_JMP
| BPF_JSET
| BPF_X
:
460 case BPF_JMP
| BPF_JGT
| BPF_K
:
461 case BPF_JMP
| BPF_JGT
| BPF_X
:
462 case BPF_JMP
| BPF_JGE
| BPF_K
:
463 case BPF_JMP
| BPF_JGE
| BPF_X
:
464 if (BPF_SRC(fp
->code
) == BPF_K
&& (int) fp
->k
< 0) {
465 /* BPF immediates are signed, zero extend
466 * immediate into tmp register and use it
469 *insn
++ = BPF_MOV32_IMM(BPF_REG_TMP
, fp
->k
);
471 insn
->dst_reg
= BPF_REG_A
;
472 insn
->src_reg
= BPF_REG_TMP
;
475 insn
->dst_reg
= BPF_REG_A
;
476 insn
->src_reg
= BPF_REG_X
;
478 bpf_src
= BPF_SRC(fp
->code
);
481 /* Common case where 'jump_false' is next insn. */
483 insn
->code
= BPF_JMP
| BPF_OP(fp
->code
) | bpf_src
;
484 target
= i
+ fp
->jt
+ 1;
489 /* Convert JEQ into JNE when 'jump_true' is next insn. */
490 if (fp
->jt
== 0 && BPF_OP(fp
->code
) == BPF_JEQ
) {
491 insn
->code
= BPF_JMP
| BPF_JNE
| bpf_src
;
492 target
= i
+ fp
->jf
+ 1;
497 /* Other jumps are mapped into two insns: Jxx and JA. */
498 target
= i
+ fp
->jt
+ 1;
499 insn
->code
= BPF_JMP
| BPF_OP(fp
->code
) | bpf_src
;
503 insn
->code
= BPF_JMP
| BPF_JA
;
504 target
= i
+ fp
->jf
+ 1;
508 /* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */
509 case BPF_LDX
| BPF_MSH
| BPF_B
:
511 *insn
++ = BPF_MOV64_REG(BPF_REG_TMP
, BPF_REG_A
);
512 /* A = BPF_R0 = *(u8 *) (skb->data + K) */
513 *insn
++ = BPF_LD_ABS(BPF_B
, fp
->k
);
515 *insn
++ = BPF_ALU32_IMM(BPF_AND
, BPF_REG_A
, 0xf);
517 *insn
++ = BPF_ALU32_IMM(BPF_LSH
, BPF_REG_A
, 2);
519 *insn
++ = BPF_MOV64_REG(BPF_REG_X
, BPF_REG_A
);
521 *insn
= BPF_MOV64_REG(BPF_REG_A
, BPF_REG_TMP
);
524 /* RET_K, RET_A are remaped into 2 insns. */
525 case BPF_RET
| BPF_A
:
526 case BPF_RET
| BPF_K
:
527 *insn
++ = BPF_MOV32_RAW(BPF_RVAL(fp
->code
) == BPF_K
?
528 BPF_K
: BPF_X
, BPF_REG_0
,
530 *insn
= BPF_EXIT_INSN();
533 /* Store to stack. */
536 *insn
= BPF_STX_MEM(BPF_W
, BPF_REG_FP
, BPF_CLASS(fp
->code
) ==
537 BPF_ST
? BPF_REG_A
: BPF_REG_X
,
538 -(BPF_MEMWORDS
- fp
->k
) * 4);
541 /* Load from stack. */
542 case BPF_LD
| BPF_MEM
:
543 case BPF_LDX
| BPF_MEM
:
544 *insn
= BPF_LDX_MEM(BPF_W
, BPF_CLASS(fp
->code
) == BPF_LD
?
545 BPF_REG_A
: BPF_REG_X
, BPF_REG_FP
,
546 -(BPF_MEMWORDS
- fp
->k
) * 4);
550 case BPF_LD
| BPF_IMM
:
551 case BPF_LDX
| BPF_IMM
:
552 *insn
= BPF_MOV32_IMM(BPF_CLASS(fp
->code
) == BPF_LD
?
553 BPF_REG_A
: BPF_REG_X
, fp
->k
);
557 case BPF_MISC
| BPF_TAX
:
558 *insn
= BPF_MOV64_REG(BPF_REG_X
, BPF_REG_A
);
562 case BPF_MISC
| BPF_TXA
:
563 *insn
= BPF_MOV64_REG(BPF_REG_A
, BPF_REG_X
);
566 /* A = skb->len or X = skb->len */
567 case BPF_LD
| BPF_W
| BPF_LEN
:
568 case BPF_LDX
| BPF_W
| BPF_LEN
:
569 *insn
= BPF_LDX_MEM(BPF_W
, BPF_CLASS(fp
->code
) == BPF_LD
?
570 BPF_REG_A
: BPF_REG_X
, BPF_REG_CTX
,
571 offsetof(struct sk_buff
, len
));
574 /* Access seccomp_data fields. */
575 case BPF_LDX
| BPF_ABS
| BPF_W
:
576 /* A = *(u32 *) (ctx + K) */
577 *insn
= BPF_LDX_MEM(BPF_W
, BPF_REG_A
, BPF_REG_CTX
, fp
->k
);
580 /* Unknown instruction. */
587 memcpy(new_insn
, tmp_insns
,
588 sizeof(*insn
) * (insn
- tmp_insns
));
589 new_insn
+= insn
- tmp_insns
;
593 /* Only calculating new length. */
594 *new_len
= new_insn
- new_prog
;
599 if (new_flen
!= new_insn
- new_prog
) {
600 new_flen
= new_insn
- new_prog
;
607 BUG_ON(*new_len
!= new_flen
);
616 * As we dont want to clear mem[] array for each packet going through
617 * __bpf_prog_run(), we check that filter loaded by user never try to read
618 * a cell if not previously written, and we check all branches to be sure
619 * a malicious user doesn't try to abuse us.
621 static int check_load_and_stores(const struct sock_filter
*filter
, int flen
)
623 u16
*masks
, memvalid
= 0; /* One bit per cell, 16 cells */
626 BUILD_BUG_ON(BPF_MEMWORDS
> 16);
628 masks
= kmalloc_array(flen
, sizeof(*masks
), GFP_KERNEL
);
632 memset(masks
, 0xff, flen
* sizeof(*masks
));
634 for (pc
= 0; pc
< flen
; pc
++) {
635 memvalid
&= masks
[pc
];
637 switch (filter
[pc
].code
) {
640 memvalid
|= (1 << filter
[pc
].k
);
642 case BPF_LD
| BPF_MEM
:
643 case BPF_LDX
| BPF_MEM
:
644 if (!(memvalid
& (1 << filter
[pc
].k
))) {
649 case BPF_JMP
| BPF_JA
:
650 /* A jump must set masks on target */
651 masks
[pc
+ 1 + filter
[pc
].k
] &= memvalid
;
654 case BPF_JMP
| BPF_JEQ
| BPF_K
:
655 case BPF_JMP
| BPF_JEQ
| BPF_X
:
656 case BPF_JMP
| BPF_JGE
| BPF_K
:
657 case BPF_JMP
| BPF_JGE
| BPF_X
:
658 case BPF_JMP
| BPF_JGT
| BPF_K
:
659 case BPF_JMP
| BPF_JGT
| BPF_X
:
660 case BPF_JMP
| BPF_JSET
| BPF_K
:
661 case BPF_JMP
| BPF_JSET
| BPF_X
:
662 /* A jump must set masks on targets */
663 masks
[pc
+ 1 + filter
[pc
].jt
] &= memvalid
;
664 masks
[pc
+ 1 + filter
[pc
].jf
] &= memvalid
;
674 static bool chk_code_allowed(u16 code_to_probe
)
676 static const bool codes
[] = {
677 /* 32 bit ALU operations */
678 [BPF_ALU
| BPF_ADD
| BPF_K
] = true,
679 [BPF_ALU
| BPF_ADD
| BPF_X
] = true,
680 [BPF_ALU
| BPF_SUB
| BPF_K
] = true,
681 [BPF_ALU
| BPF_SUB
| BPF_X
] = true,
682 [BPF_ALU
| BPF_MUL
| BPF_K
] = true,
683 [BPF_ALU
| BPF_MUL
| BPF_X
] = true,
684 [BPF_ALU
| BPF_DIV
| BPF_K
] = true,
685 [BPF_ALU
| BPF_DIV
| BPF_X
] = true,
686 [BPF_ALU
| BPF_MOD
| BPF_K
] = true,
687 [BPF_ALU
| BPF_MOD
| BPF_X
] = true,
688 [BPF_ALU
| BPF_AND
| BPF_K
] = true,
689 [BPF_ALU
| BPF_AND
| BPF_X
] = true,
690 [BPF_ALU
| BPF_OR
| BPF_K
] = true,
691 [BPF_ALU
| BPF_OR
| BPF_X
] = true,
692 [BPF_ALU
| BPF_XOR
| BPF_K
] = true,
693 [BPF_ALU
| BPF_XOR
| BPF_X
] = true,
694 [BPF_ALU
| BPF_LSH
| BPF_K
] = true,
695 [BPF_ALU
| BPF_LSH
| BPF_X
] = true,
696 [BPF_ALU
| BPF_RSH
| BPF_K
] = true,
697 [BPF_ALU
| BPF_RSH
| BPF_X
] = true,
698 [BPF_ALU
| BPF_NEG
] = true,
699 /* Load instructions */
700 [BPF_LD
| BPF_W
| BPF_ABS
] = true,
701 [BPF_LD
| BPF_H
| BPF_ABS
] = true,
702 [BPF_LD
| BPF_B
| BPF_ABS
] = true,
703 [BPF_LD
| BPF_W
| BPF_LEN
] = true,
704 [BPF_LD
| BPF_W
| BPF_IND
] = true,
705 [BPF_LD
| BPF_H
| BPF_IND
] = true,
706 [BPF_LD
| BPF_B
| BPF_IND
] = true,
707 [BPF_LD
| BPF_IMM
] = true,
708 [BPF_LD
| BPF_MEM
] = true,
709 [BPF_LDX
| BPF_W
| BPF_LEN
] = true,
710 [BPF_LDX
| BPF_B
| BPF_MSH
] = true,
711 [BPF_LDX
| BPF_IMM
] = true,
712 [BPF_LDX
| BPF_MEM
] = true,
713 /* Store instructions */
716 /* Misc instructions */
717 [BPF_MISC
| BPF_TAX
] = true,
718 [BPF_MISC
| BPF_TXA
] = true,
719 /* Return instructions */
720 [BPF_RET
| BPF_K
] = true,
721 [BPF_RET
| BPF_A
] = true,
722 /* Jump instructions */
723 [BPF_JMP
| BPF_JA
] = true,
724 [BPF_JMP
| BPF_JEQ
| BPF_K
] = true,
725 [BPF_JMP
| BPF_JEQ
| BPF_X
] = true,
726 [BPF_JMP
| BPF_JGE
| BPF_K
] = true,
727 [BPF_JMP
| BPF_JGE
| BPF_X
] = true,
728 [BPF_JMP
| BPF_JGT
| BPF_K
] = true,
729 [BPF_JMP
| BPF_JGT
| BPF_X
] = true,
730 [BPF_JMP
| BPF_JSET
| BPF_K
] = true,
731 [BPF_JMP
| BPF_JSET
| BPF_X
] = true,
734 if (code_to_probe
>= ARRAY_SIZE(codes
))
737 return codes
[code_to_probe
];
741 * bpf_check_classic - verify socket filter code
742 * @filter: filter to verify
743 * @flen: length of filter
745 * Check the user's filter code. If we let some ugly
746 * filter code slip through kaboom! The filter must contain
747 * no references or jumps that are out of range, no illegal
748 * instructions, and must end with a RET instruction.
750 * All jumps are forward as they are not signed.
752 * Returns 0 if the rule set is legal or -EINVAL if not.
754 int bpf_check_classic(const struct sock_filter
*filter
, unsigned int flen
)
759 if (flen
== 0 || flen
> BPF_MAXINSNS
)
762 /* Check the filter code now */
763 for (pc
= 0; pc
< flen
; pc
++) {
764 const struct sock_filter
*ftest
= &filter
[pc
];
766 /* May we actually operate on this code? */
767 if (!chk_code_allowed(ftest
->code
))
770 /* Some instructions need special checks */
771 switch (ftest
->code
) {
772 case BPF_ALU
| BPF_DIV
| BPF_K
:
773 case BPF_ALU
| BPF_MOD
| BPF_K
:
774 /* Check for division by zero */
778 case BPF_LD
| BPF_MEM
:
779 case BPF_LDX
| BPF_MEM
:
782 /* Check for invalid memory addresses */
783 if (ftest
->k
>= BPF_MEMWORDS
)
786 case BPF_JMP
| BPF_JA
:
787 /* Note, the large ftest->k might cause loops.
788 * Compare this with conditional jumps below,
789 * where offsets are limited. --ANK (981016)
791 if (ftest
->k
>= (unsigned int)(flen
- pc
- 1))
794 case BPF_JMP
| BPF_JEQ
| BPF_K
:
795 case BPF_JMP
| BPF_JEQ
| BPF_X
:
796 case BPF_JMP
| BPF_JGE
| BPF_K
:
797 case BPF_JMP
| BPF_JGE
| BPF_X
:
798 case BPF_JMP
| BPF_JGT
| BPF_K
:
799 case BPF_JMP
| BPF_JGT
| BPF_X
:
800 case BPF_JMP
| BPF_JSET
| BPF_K
:
801 case BPF_JMP
| BPF_JSET
| BPF_X
:
802 /* Both conditionals must be safe */
803 if (pc
+ ftest
->jt
+ 1 >= flen
||
804 pc
+ ftest
->jf
+ 1 >= flen
)
807 case BPF_LD
| BPF_W
| BPF_ABS
:
808 case BPF_LD
| BPF_H
| BPF_ABS
:
809 case BPF_LD
| BPF_B
| BPF_ABS
:
811 if (bpf_anc_helper(ftest
) & BPF_ANC
)
813 /* Ancillary operation unknown or unsupported */
814 if (anc_found
== false && ftest
->k
>= SKF_AD_OFF
)
819 /* Last instruction must be a RET code */
820 switch (filter
[flen
- 1].code
) {
821 case BPF_RET
| BPF_K
:
822 case BPF_RET
| BPF_A
:
823 return check_load_and_stores(filter
, flen
);
828 EXPORT_SYMBOL(bpf_check_classic
);
830 static int bpf_prog_store_orig_filter(struct bpf_prog
*fp
,
831 const struct sock_fprog
*fprog
)
833 unsigned int fsize
= bpf_classic_proglen(fprog
);
834 struct sock_fprog_kern
*fkprog
;
836 fp
->orig_prog
= kmalloc(sizeof(*fkprog
), GFP_KERNEL
);
840 fkprog
= fp
->orig_prog
;
841 fkprog
->len
= fprog
->len
;
842 fkprog
->filter
= kmemdup(fp
->insns
, fsize
, GFP_KERNEL
);
843 if (!fkprog
->filter
) {
844 kfree(fp
->orig_prog
);
851 static void bpf_release_orig_filter(struct bpf_prog
*fp
)
853 struct sock_fprog_kern
*fprog
= fp
->orig_prog
;
856 kfree(fprog
->filter
);
861 static void __bpf_prog_release(struct bpf_prog
*prog
)
863 if (prog
->type
== BPF_PROG_TYPE_SOCKET_FILTER
) {
866 bpf_release_orig_filter(prog
);
871 static void __sk_filter_release(struct sk_filter
*fp
)
873 __bpf_prog_release(fp
->prog
);
878 * sk_filter_release_rcu - Release a socket filter by rcu_head
879 * @rcu: rcu_head that contains the sk_filter to free
881 static void sk_filter_release_rcu(struct rcu_head
*rcu
)
883 struct sk_filter
*fp
= container_of(rcu
, struct sk_filter
, rcu
);
885 __sk_filter_release(fp
);
889 * sk_filter_release - release a socket filter
890 * @fp: filter to remove
892 * Remove a filter from a socket and release its resources.
894 static void sk_filter_release(struct sk_filter
*fp
)
896 if (atomic_dec_and_test(&fp
->refcnt
))
897 call_rcu(&fp
->rcu
, sk_filter_release_rcu
);
900 void sk_filter_uncharge(struct sock
*sk
, struct sk_filter
*fp
)
902 u32 filter_size
= bpf_prog_size(fp
->prog
->len
);
904 atomic_sub(filter_size
, &sk
->sk_omem_alloc
);
905 sk_filter_release(fp
);
908 /* try to charge the socket memory if there is space available
909 * return true on success
911 bool sk_filter_charge(struct sock
*sk
, struct sk_filter
*fp
)
913 u32 filter_size
= bpf_prog_size(fp
->prog
->len
);
915 /* same check as in sock_kmalloc() */
916 if (filter_size
<= sysctl_optmem_max
&&
917 atomic_read(&sk
->sk_omem_alloc
) + filter_size
< sysctl_optmem_max
) {
918 atomic_inc(&fp
->refcnt
);
919 atomic_add(filter_size
, &sk
->sk_omem_alloc
);
925 static struct bpf_prog
*bpf_migrate_filter(struct bpf_prog
*fp
)
927 struct sock_filter
*old_prog
;
928 struct bpf_prog
*old_fp
;
929 int err
, new_len
, old_len
= fp
->len
;
931 /* We are free to overwrite insns et al right here as it
932 * won't be used at this point in time anymore internally
933 * after the migration to the internal BPF instruction
936 BUILD_BUG_ON(sizeof(struct sock_filter
) !=
937 sizeof(struct bpf_insn
));
939 /* Conversion cannot happen on overlapping memory areas,
940 * so we need to keep the user BPF around until the 2nd
941 * pass. At this time, the user BPF is stored in fp->insns.
943 old_prog
= kmemdup(fp
->insns
, old_len
* sizeof(struct sock_filter
),
950 /* 1st pass: calculate the new program length. */
951 err
= bpf_convert_filter(old_prog
, old_len
, NULL
, &new_len
);
955 /* Expand fp for appending the new filter representation. */
957 fp
= bpf_prog_realloc(old_fp
, bpf_prog_size(new_len
), 0);
959 /* The old_fp is still around in case we couldn't
960 * allocate new memory, so uncharge on that one.
969 /* 2nd pass: remap sock_filter insns into bpf_insn insns. */
970 err
= bpf_convert_filter(old_prog
, old_len
, fp
->insnsi
, &new_len
);
972 /* 2nd bpf_convert_filter() can fail only if it fails
973 * to allocate memory, remapping must succeed. Note,
974 * that at this time old_fp has already been released
979 bpf_prog_select_runtime(fp
);
987 __bpf_prog_release(fp
);
991 static struct bpf_prog
*bpf_prepare_filter(struct bpf_prog
*fp
)
998 err
= bpf_check_classic(fp
->insns
, fp
->len
);
1000 __bpf_prog_release(fp
);
1001 return ERR_PTR(err
);
1004 /* Probe if we can JIT compile the filter and if so, do
1005 * the compilation of the filter.
1007 bpf_jit_compile(fp
);
1009 /* JIT compiler couldn't process this filter, so do the
1010 * internal BPF translation for the optimized interpreter.
1013 fp
= bpf_migrate_filter(fp
);
1019 * bpf_prog_create - create an unattached filter
1020 * @pfp: the unattached filter that is created
1021 * @fprog: the filter program
1023 * Create a filter independent of any socket. We first run some
1024 * sanity checks on it to make sure it does not explode on us later.
1025 * If an error occurs or there is insufficient memory for the filter
1026 * a negative errno code is returned. On success the return is zero.
1028 int bpf_prog_create(struct bpf_prog
**pfp
, struct sock_fprog_kern
*fprog
)
1030 unsigned int fsize
= bpf_classic_proglen(fprog
);
1031 struct bpf_prog
*fp
;
1033 /* Make sure new filter is there and in the right amounts. */
1034 if (fprog
->filter
== NULL
)
1037 fp
= bpf_prog_alloc(bpf_prog_size(fprog
->len
), 0);
1041 memcpy(fp
->insns
, fprog
->filter
, fsize
);
1043 fp
->len
= fprog
->len
;
1044 /* Since unattached filters are not copied back to user
1045 * space through sk_get_filter(), we do not need to hold
1046 * a copy here, and can spare us the work.
1048 fp
->orig_prog
= NULL
;
1050 /* bpf_prepare_filter() already takes care of freeing
1051 * memory in case something goes wrong.
1053 fp
= bpf_prepare_filter(fp
);
1060 EXPORT_SYMBOL_GPL(bpf_prog_create
);
1062 void bpf_prog_destroy(struct bpf_prog
*fp
)
1064 __bpf_prog_release(fp
);
1066 EXPORT_SYMBOL_GPL(bpf_prog_destroy
);
1068 static int __sk_attach_prog(struct bpf_prog
*prog
, struct sock
*sk
)
1070 struct sk_filter
*fp
, *old_fp
;
1072 fp
= kmalloc(sizeof(*fp
), GFP_KERNEL
);
1077 atomic_set(&fp
->refcnt
, 0);
1079 if (!sk_filter_charge(sk
, fp
)) {
1084 old_fp
= rcu_dereference_protected(sk
->sk_filter
,
1085 sock_owned_by_user(sk
));
1086 rcu_assign_pointer(sk
->sk_filter
, fp
);
1089 sk_filter_uncharge(sk
, old_fp
);
1095 * sk_attach_filter - attach a socket filter
1096 * @fprog: the filter program
1097 * @sk: the socket to use
1099 * Attach the user's filter code. We first run some sanity checks on
1100 * it to make sure it does not explode on us later. If an error
1101 * occurs or there is insufficient memory for the filter a negative
1102 * errno code is returned. On success the return is zero.
1104 int sk_attach_filter(struct sock_fprog
*fprog
, struct sock
*sk
)
1106 unsigned int fsize
= bpf_classic_proglen(fprog
);
1107 unsigned int bpf_fsize
= bpf_prog_size(fprog
->len
);
1108 struct bpf_prog
*prog
;
1111 if (sock_flag(sk
, SOCK_FILTER_LOCKED
))
1114 /* Make sure new filter is there and in the right amounts. */
1115 if (fprog
->filter
== NULL
)
1118 prog
= bpf_prog_alloc(bpf_fsize
, 0);
1122 if (copy_from_user(prog
->insns
, fprog
->filter
, fsize
)) {
1123 __bpf_prog_free(prog
);
1127 prog
->len
= fprog
->len
;
1129 err
= bpf_prog_store_orig_filter(prog
, fprog
);
1131 __bpf_prog_free(prog
);
1135 /* bpf_prepare_filter() already takes care of freeing
1136 * memory in case something goes wrong.
1138 prog
= bpf_prepare_filter(prog
);
1140 return PTR_ERR(prog
);
1142 err
= __sk_attach_prog(prog
, sk
);
1144 __bpf_prog_release(prog
);
1150 EXPORT_SYMBOL_GPL(sk_attach_filter
);
1152 int sk_attach_bpf(u32 ufd
, struct sock
*sk
)
1154 struct bpf_prog
*prog
;
1157 if (sock_flag(sk
, SOCK_FILTER_LOCKED
))
1160 prog
= bpf_prog_get(ufd
);
1162 return PTR_ERR(prog
);
1164 if (prog
->type
!= BPF_PROG_TYPE_SOCKET_FILTER
) {
1169 err
= __sk_attach_prog(prog
, sk
);
1179 * bpf_skb_clone_not_writable - is the header of a clone not writable
1180 * @skb: buffer to check
1181 * @len: length up to which to write, can be negative
1183 * Returns true if modifying the header part of the cloned buffer
1184 * does require the data to be copied. I.e. this version works with
1185 * negative lengths needed for eBPF case!
1187 static bool bpf_skb_clone_unwritable(const struct sk_buff
*skb
, int len
)
1189 return skb_header_cloned(skb
) ||
1190 (int) skb_headroom(skb
) + len
> skb
->hdr_len
;
1193 #define BPF_RECOMPUTE_CSUM(flags) ((flags) & 1)
1195 static u64
bpf_skb_store_bytes(u64 r1
, u64 r2
, u64 r3
, u64 r4
, u64 flags
)
1197 struct sk_buff
*skb
= (struct sk_buff
*) (long) r1
;
1198 int offset
= (int) r2
;
1199 void *from
= (void *) (long) r3
;
1200 unsigned int len
= (unsigned int) r4
;
1204 /* bpf verifier guarantees that:
1205 * 'from' pointer points to bpf program stack
1206 * 'len' bytes of it were initialized
1208 * 'skb' is a valid pointer to 'struct sk_buff'
1210 * so check for invalid 'offset' and too large 'len'
1212 if (unlikely((u32
) offset
> 0xffff || len
> sizeof(buf
)))
1215 offset
-= skb
->data
- skb_mac_header(skb
);
1216 if (unlikely(skb_cloned(skb
) &&
1217 bpf_skb_clone_unwritable(skb
, offset
+ len
)))
1220 ptr
= skb_header_pointer(skb
, offset
, len
, buf
);
1224 if (BPF_RECOMPUTE_CSUM(flags
))
1225 skb_postpull_rcsum(skb
, ptr
, len
);
1227 memcpy(ptr
, from
, len
);
1230 /* skb_store_bits cannot return -EFAULT here */
1231 skb_store_bits(skb
, offset
, ptr
, len
);
1233 if (BPF_RECOMPUTE_CSUM(flags
) && skb
->ip_summed
== CHECKSUM_COMPLETE
)
1234 skb
->csum
= csum_add(skb
->csum
, csum_partial(ptr
, len
, 0));
1238 const struct bpf_func_proto bpf_skb_store_bytes_proto
= {
1239 .func
= bpf_skb_store_bytes
,
1241 .ret_type
= RET_INTEGER
,
1242 .arg1_type
= ARG_PTR_TO_CTX
,
1243 .arg2_type
= ARG_ANYTHING
,
1244 .arg3_type
= ARG_PTR_TO_STACK
,
1245 .arg4_type
= ARG_CONST_STACK_SIZE
,
1246 .arg5_type
= ARG_ANYTHING
,
1249 #define BPF_HEADER_FIELD_SIZE(flags) ((flags) & 0x0f)
1250 #define BPF_IS_PSEUDO_HEADER(flags) ((flags) & 0x10)
1252 static u64
bpf_l3_csum_replace(u64 r1
, u64 r2
, u64 from
, u64 to
, u64 flags
)
1254 struct sk_buff
*skb
= (struct sk_buff
*) (long) r1
;
1255 int offset
= (int) r2
;
1258 if (unlikely((u32
) offset
> 0xffff))
1261 offset
-= skb
->data
- skb_mac_header(skb
);
1262 if (unlikely(skb_cloned(skb
) &&
1263 bpf_skb_clone_unwritable(skb
, offset
+ sizeof(sum
))))
1266 ptr
= skb_header_pointer(skb
, offset
, sizeof(sum
), &sum
);
1270 switch (BPF_HEADER_FIELD_SIZE(flags
)) {
1272 csum_replace2(ptr
, from
, to
);
1275 csum_replace4(ptr
, from
, to
);
1282 /* skb_store_bits guaranteed to not return -EFAULT here */
1283 skb_store_bits(skb
, offset
, ptr
, sizeof(sum
));
1288 const struct bpf_func_proto bpf_l3_csum_replace_proto
= {
1289 .func
= bpf_l3_csum_replace
,
1291 .ret_type
= RET_INTEGER
,
1292 .arg1_type
= ARG_PTR_TO_CTX
,
1293 .arg2_type
= ARG_ANYTHING
,
1294 .arg3_type
= ARG_ANYTHING
,
1295 .arg4_type
= ARG_ANYTHING
,
1296 .arg5_type
= ARG_ANYTHING
,
1299 static u64
bpf_l4_csum_replace(u64 r1
, u64 r2
, u64 from
, u64 to
, u64 flags
)
1301 struct sk_buff
*skb
= (struct sk_buff
*) (long) r1
;
1302 u32 is_pseudo
= BPF_IS_PSEUDO_HEADER(flags
);
1303 int offset
= (int) r2
;
1306 if (unlikely((u32
) offset
> 0xffff))
1309 offset
-= skb
->data
- skb_mac_header(skb
);
1310 if (unlikely(skb_cloned(skb
) &&
1311 bpf_skb_clone_unwritable(skb
, offset
+ sizeof(sum
))))
1314 ptr
= skb_header_pointer(skb
, offset
, sizeof(sum
), &sum
);
1318 switch (BPF_HEADER_FIELD_SIZE(flags
)) {
1320 inet_proto_csum_replace2(ptr
, skb
, from
, to
, is_pseudo
);
1323 inet_proto_csum_replace4(ptr
, skb
, from
, to
, is_pseudo
);
1330 /* skb_store_bits guaranteed to not return -EFAULT here */
1331 skb_store_bits(skb
, offset
, ptr
, sizeof(sum
));
1336 const struct bpf_func_proto bpf_l4_csum_replace_proto
= {
1337 .func
= bpf_l4_csum_replace
,
1339 .ret_type
= RET_INTEGER
,
1340 .arg1_type
= ARG_PTR_TO_CTX
,
1341 .arg2_type
= ARG_ANYTHING
,
1342 .arg3_type
= ARG_ANYTHING
,
1343 .arg4_type
= ARG_ANYTHING
,
1344 .arg5_type
= ARG_ANYTHING
,
1347 static const struct bpf_func_proto
*
1348 sk_filter_func_proto(enum bpf_func_id func_id
)
1351 case BPF_FUNC_map_lookup_elem
:
1352 return &bpf_map_lookup_elem_proto
;
1353 case BPF_FUNC_map_update_elem
:
1354 return &bpf_map_update_elem_proto
;
1355 case BPF_FUNC_map_delete_elem
:
1356 return &bpf_map_delete_elem_proto
;
1357 case BPF_FUNC_get_prandom_u32
:
1358 return &bpf_get_prandom_u32_proto
;
1359 case BPF_FUNC_get_smp_processor_id
:
1360 return &bpf_get_smp_processor_id_proto
;
1366 static const struct bpf_func_proto
*
1367 tc_cls_act_func_proto(enum bpf_func_id func_id
)
1370 case BPF_FUNC_skb_store_bytes
:
1371 return &bpf_skb_store_bytes_proto
;
1372 case BPF_FUNC_l3_csum_replace
:
1373 return &bpf_l3_csum_replace_proto
;
1374 case BPF_FUNC_l4_csum_replace
:
1375 return &bpf_l4_csum_replace_proto
;
1377 return sk_filter_func_proto(func_id
);
1381 static bool sk_filter_is_valid_access(int off
, int size
,
1382 enum bpf_access_type type
)
1384 /* only read is allowed */
1385 if (type
!= BPF_READ
)
1389 if (off
< 0 || off
>= sizeof(struct __sk_buff
))
1392 /* disallow misaligned access */
1393 if (off
% size
!= 0)
1396 /* all __sk_buff fields are __u32 */
1403 static u32
sk_filter_convert_ctx_access(int dst_reg
, int src_reg
, int ctx_off
,
1404 struct bpf_insn
*insn_buf
)
1406 struct bpf_insn
*insn
= insn_buf
;
1409 case offsetof(struct __sk_buff
, len
):
1410 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, len
) != 4);
1412 *insn
++ = BPF_LDX_MEM(BPF_W
, dst_reg
, src_reg
,
1413 offsetof(struct sk_buff
, len
));
1416 case offsetof(struct __sk_buff
, protocol
):
1417 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, protocol
) != 2);
1419 *insn
++ = BPF_LDX_MEM(BPF_H
, dst_reg
, src_reg
,
1420 offsetof(struct sk_buff
, protocol
));
1423 case offsetof(struct __sk_buff
, vlan_proto
):
1424 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, vlan_proto
) != 2);
1426 *insn
++ = BPF_LDX_MEM(BPF_H
, dst_reg
, src_reg
,
1427 offsetof(struct sk_buff
, vlan_proto
));
1430 case offsetof(struct __sk_buff
, priority
):
1431 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, priority
) != 4);
1433 *insn
++ = BPF_LDX_MEM(BPF_W
, dst_reg
, src_reg
,
1434 offsetof(struct sk_buff
, priority
));
1437 case offsetof(struct __sk_buff
, mark
):
1438 return convert_skb_access(SKF_AD_MARK
, dst_reg
, src_reg
, insn
);
1440 case offsetof(struct __sk_buff
, pkt_type
):
1441 return convert_skb_access(SKF_AD_PKTTYPE
, dst_reg
, src_reg
, insn
);
1443 case offsetof(struct __sk_buff
, queue_mapping
):
1444 return convert_skb_access(SKF_AD_QUEUE
, dst_reg
, src_reg
, insn
);
1446 case offsetof(struct __sk_buff
, vlan_present
):
1447 return convert_skb_access(SKF_AD_VLAN_TAG_PRESENT
,
1448 dst_reg
, src_reg
, insn
);
1450 case offsetof(struct __sk_buff
, vlan_tci
):
1451 return convert_skb_access(SKF_AD_VLAN_TAG
,
1452 dst_reg
, src_reg
, insn
);
1455 return insn
- insn_buf
;
1458 static const struct bpf_verifier_ops sk_filter_ops
= {
1459 .get_func_proto
= sk_filter_func_proto
,
1460 .is_valid_access
= sk_filter_is_valid_access
,
1461 .convert_ctx_access
= sk_filter_convert_ctx_access
,
1464 static const struct bpf_verifier_ops tc_cls_act_ops
= {
1465 .get_func_proto
= tc_cls_act_func_proto
,
1466 .is_valid_access
= sk_filter_is_valid_access
,
1467 .convert_ctx_access
= sk_filter_convert_ctx_access
,
1470 static struct bpf_prog_type_list sk_filter_type __read_mostly
= {
1471 .ops
= &sk_filter_ops
,
1472 .type
= BPF_PROG_TYPE_SOCKET_FILTER
,
1475 static struct bpf_prog_type_list sched_cls_type __read_mostly
= {
1476 .ops
= &tc_cls_act_ops
,
1477 .type
= BPF_PROG_TYPE_SCHED_CLS
,
1480 static struct bpf_prog_type_list sched_act_type __read_mostly
= {
1481 .ops
= &tc_cls_act_ops
,
1482 .type
= BPF_PROG_TYPE_SCHED_ACT
,
1485 static int __init
register_sk_filter_ops(void)
1487 bpf_register_prog_type(&sk_filter_type
);
1488 bpf_register_prog_type(&sched_cls_type
);
1489 bpf_register_prog_type(&sched_act_type
);
1493 late_initcall(register_sk_filter_ops
);
1495 int sk_detach_filter(struct sock
*sk
)
1498 struct sk_filter
*filter
;
1500 if (sock_flag(sk
, SOCK_FILTER_LOCKED
))
1503 filter
= rcu_dereference_protected(sk
->sk_filter
,
1504 sock_owned_by_user(sk
));
1506 RCU_INIT_POINTER(sk
->sk_filter
, NULL
);
1507 sk_filter_uncharge(sk
, filter
);
1513 EXPORT_SYMBOL_GPL(sk_detach_filter
);
1515 int sk_get_filter(struct sock
*sk
, struct sock_filter __user
*ubuf
,
1518 struct sock_fprog_kern
*fprog
;
1519 struct sk_filter
*filter
;
1523 filter
= rcu_dereference_protected(sk
->sk_filter
,
1524 sock_owned_by_user(sk
));
1528 /* We're copying the filter that has been originally attached,
1529 * so no conversion/decode needed anymore.
1531 fprog
= filter
->prog
->orig_prog
;
1535 /* User space only enquires number of filter blocks. */
1539 if (len
< fprog
->len
)
1543 if (copy_to_user(ubuf
, fprog
->filter
, bpf_classic_proglen(fprog
)))
1546 /* Instead of bytes, the API requests to return the number