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[mirror_ubuntu-bionic-kernel.git] / net / core / filter.c
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/module.h>
25 #include <linux/types.h>
26 #include <linux/mm.h>
27 #include <linux/fcntl.h>
28 #include <linux/socket.h>
29 #include <linux/in.h>
30 #include <linux/inet.h>
31 #include <linux/netdevice.h>
32 #include <linux/if_packet.h>
33 #include <linux/gfp.h>
34 #include <net/ip.h>
35 #include <net/protocol.h>
36 #include <net/netlink.h>
37 #include <linux/skbuff.h>
38 #include <net/sock.h>
39 #include <net/flow_dissector.h>
40 #include <linux/errno.h>
41 #include <linux/timer.h>
42 #include <asm/uaccess.h>
43 #include <asm/unaligned.h>
44 #include <linux/filter.h>
45 #include <linux/ratelimit.h>
46 #include <linux/seccomp.h>
47 #include <linux/if_vlan.h>
48 #include <linux/bpf.h>
49 #include <net/sch_generic.h>
50 #include <net/cls_cgroup.h>
51 #include <net/dst_metadata.h>
52 #include <net/dst.h>
53
54 /**
55 * sk_filter - run a packet through a socket filter
56 * @sk: sock associated with &sk_buff
57 * @skb: buffer to filter
58 *
59 * Run the eBPF program and then cut skb->data to correct size returned by
60 * the program. If pkt_len is 0 we toss packet. If skb->len is smaller
61 * than pkt_len we keep whole skb->data. This is the socket level
62 * wrapper to BPF_PROG_RUN. It returns 0 if the packet should
63 * be accepted or -EPERM if the packet should be tossed.
64 *
65 */
66 int sk_filter(struct sock *sk, struct sk_buff *skb)
67 {
68 int err;
69 struct sk_filter *filter;
70
71 /*
72 * If the skb was allocated from pfmemalloc reserves, only
73 * allow SOCK_MEMALLOC sockets to use it as this socket is
74 * helping free memory
75 */
76 if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
77 return -ENOMEM;
78
79 err = security_sock_rcv_skb(sk, skb);
80 if (err)
81 return err;
82
83 rcu_read_lock();
84 filter = rcu_dereference(sk->sk_filter);
85 if (filter) {
86 unsigned int pkt_len = bpf_prog_run_save_cb(filter->prog, skb);
87
88 err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
89 }
90 rcu_read_unlock();
91
92 return err;
93 }
94 EXPORT_SYMBOL(sk_filter);
95
96 static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
97 {
98 return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
99 }
100
101 static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
102 {
103 struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
104 struct nlattr *nla;
105
106 if (skb_is_nonlinear(skb))
107 return 0;
108
109 if (skb->len < sizeof(struct nlattr))
110 return 0;
111
112 if (a > skb->len - sizeof(struct nlattr))
113 return 0;
114
115 nla = nla_find((struct nlattr *) &skb->data[a], skb->len - a, x);
116 if (nla)
117 return (void *) nla - (void *) skb->data;
118
119 return 0;
120 }
121
122 static u64 __skb_get_nlattr_nest(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
123 {
124 struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
125 struct nlattr *nla;
126
127 if (skb_is_nonlinear(skb))
128 return 0;
129
130 if (skb->len < sizeof(struct nlattr))
131 return 0;
132
133 if (a > skb->len - sizeof(struct nlattr))
134 return 0;
135
136 nla = (struct nlattr *) &skb->data[a];
137 if (nla->nla_len > skb->len - a)
138 return 0;
139
140 nla = nla_find_nested(nla, x);
141 if (nla)
142 return (void *) nla - (void *) skb->data;
143
144 return 0;
145 }
146
147 static u64 __get_raw_cpu_id(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
148 {
149 return raw_smp_processor_id();
150 }
151
152 static u32 convert_skb_access(int skb_field, int dst_reg, int src_reg,
153 struct bpf_insn *insn_buf)
154 {
155 struct bpf_insn *insn = insn_buf;
156
157 switch (skb_field) {
158 case SKF_AD_MARK:
159 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
160
161 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
162 offsetof(struct sk_buff, mark));
163 break;
164
165 case SKF_AD_PKTTYPE:
166 *insn++ = BPF_LDX_MEM(BPF_B, dst_reg, src_reg, PKT_TYPE_OFFSET());
167 *insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, PKT_TYPE_MAX);
168 #ifdef __BIG_ENDIAN_BITFIELD
169 *insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 5);
170 #endif
171 break;
172
173 case SKF_AD_QUEUE:
174 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
175
176 *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
177 offsetof(struct sk_buff, queue_mapping));
178 break;
179
180 case SKF_AD_VLAN_TAG:
181 case SKF_AD_VLAN_TAG_PRESENT:
182 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
183 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
184
185 /* dst_reg = *(u16 *) (src_reg + offsetof(vlan_tci)) */
186 *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
187 offsetof(struct sk_buff, vlan_tci));
188 if (skb_field == SKF_AD_VLAN_TAG) {
189 *insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg,
190 ~VLAN_TAG_PRESENT);
191 } else {
192 /* dst_reg >>= 12 */
193 *insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 12);
194 /* dst_reg &= 1 */
195 *insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, 1);
196 }
197 break;
198 }
199
200 return insn - insn_buf;
201 }
202
203 static bool convert_bpf_extensions(struct sock_filter *fp,
204 struct bpf_insn **insnp)
205 {
206 struct bpf_insn *insn = *insnp;
207 u32 cnt;
208
209 switch (fp->k) {
210 case SKF_AD_OFF + SKF_AD_PROTOCOL:
211 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
212
213 /* A = *(u16 *) (CTX + offsetof(protocol)) */
214 *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
215 offsetof(struct sk_buff, protocol));
216 /* A = ntohs(A) [emitting a nop or swap16] */
217 *insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
218 break;
219
220 case SKF_AD_OFF + SKF_AD_PKTTYPE:
221 cnt = convert_skb_access(SKF_AD_PKTTYPE, BPF_REG_A, BPF_REG_CTX, insn);
222 insn += cnt - 1;
223 break;
224
225 case SKF_AD_OFF + SKF_AD_IFINDEX:
226 case SKF_AD_OFF + SKF_AD_HATYPE:
227 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
228 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
229 BUILD_BUG_ON(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)) < 0);
230
231 *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)),
232 BPF_REG_TMP, BPF_REG_CTX,
233 offsetof(struct sk_buff, dev));
234 /* if (tmp != 0) goto pc + 1 */
235 *insn++ = BPF_JMP_IMM(BPF_JNE, BPF_REG_TMP, 0, 1);
236 *insn++ = BPF_EXIT_INSN();
237 if (fp->k == SKF_AD_OFF + SKF_AD_IFINDEX)
238 *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_TMP,
239 offsetof(struct net_device, ifindex));
240 else
241 *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_TMP,
242 offsetof(struct net_device, type));
243 break;
244
245 case SKF_AD_OFF + SKF_AD_MARK:
246 cnt = convert_skb_access(SKF_AD_MARK, BPF_REG_A, BPF_REG_CTX, insn);
247 insn += cnt - 1;
248 break;
249
250 case SKF_AD_OFF + SKF_AD_RXHASH:
251 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
252
253 *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX,
254 offsetof(struct sk_buff, hash));
255 break;
256
257 case SKF_AD_OFF + SKF_AD_QUEUE:
258 cnt = convert_skb_access(SKF_AD_QUEUE, BPF_REG_A, BPF_REG_CTX, insn);
259 insn += cnt - 1;
260 break;
261
262 case SKF_AD_OFF + SKF_AD_VLAN_TAG:
263 cnt = convert_skb_access(SKF_AD_VLAN_TAG,
264 BPF_REG_A, BPF_REG_CTX, insn);
265 insn += cnt - 1;
266 break;
267
268 case SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT:
269 cnt = convert_skb_access(SKF_AD_VLAN_TAG_PRESENT,
270 BPF_REG_A, BPF_REG_CTX, insn);
271 insn += cnt - 1;
272 break;
273
274 case SKF_AD_OFF + SKF_AD_VLAN_TPID:
275 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
276
277 /* A = *(u16 *) (CTX + offsetof(vlan_proto)) */
278 *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
279 offsetof(struct sk_buff, vlan_proto));
280 /* A = ntohs(A) [emitting a nop or swap16] */
281 *insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
282 break;
283
284 case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
285 case SKF_AD_OFF + SKF_AD_NLATTR:
286 case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
287 case SKF_AD_OFF + SKF_AD_CPU:
288 case SKF_AD_OFF + SKF_AD_RANDOM:
289 /* arg1 = CTX */
290 *insn++ = BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_CTX);
291 /* arg2 = A */
292 *insn++ = BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_A);
293 /* arg3 = X */
294 *insn++ = BPF_MOV64_REG(BPF_REG_ARG3, BPF_REG_X);
295 /* Emit call(arg1=CTX, arg2=A, arg3=X) */
296 switch (fp->k) {
297 case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
298 *insn = BPF_EMIT_CALL(__skb_get_pay_offset);
299 break;
300 case SKF_AD_OFF + SKF_AD_NLATTR:
301 *insn = BPF_EMIT_CALL(__skb_get_nlattr);
302 break;
303 case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
304 *insn = BPF_EMIT_CALL(__skb_get_nlattr_nest);
305 break;
306 case SKF_AD_OFF + SKF_AD_CPU:
307 *insn = BPF_EMIT_CALL(__get_raw_cpu_id);
308 break;
309 case SKF_AD_OFF + SKF_AD_RANDOM:
310 *insn = BPF_EMIT_CALL(bpf_user_rnd_u32);
311 bpf_user_rnd_init_once();
312 break;
313 }
314 break;
315
316 case SKF_AD_OFF + SKF_AD_ALU_XOR_X:
317 /* A ^= X */
318 *insn = BPF_ALU32_REG(BPF_XOR, BPF_REG_A, BPF_REG_X);
319 break;
320
321 default:
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.
325 */
326 BUG_ON(__bpf_call_base(0, 0, 0, 0, 0) != 0);
327 return false;
328 }
329
330 *insnp = insn;
331 return true;
332 }
333
334 /**
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
340 *
341 * Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style.
342 * Conversion workflow:
343 *
344 * 1) First pass for calculating the new program length:
345 * bpf_convert_filter(old_prog, old_len, NULL, &new_len)
346 *
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);
351 *
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 *'.
357 */
358 static int bpf_convert_filter(struct sock_filter *prog, int len,
359 struct bpf_insn *new_prog, int *new_len)
360 {
361 int new_flen = 0, pass = 0, target, i;
362 struct bpf_insn *new_insn;
363 struct sock_filter *fp;
364 int *addrs = NULL;
365 u8 bpf_src;
366
367 BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK);
368 BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
369
370 if (len <= 0 || len > BPF_MAXINSNS)
371 return -EINVAL;
372
373 if (new_prog) {
374 addrs = kcalloc(len, sizeof(*addrs),
375 GFP_KERNEL | __GFP_NOWARN);
376 if (!addrs)
377 return -ENOMEM;
378 }
379
380 do_pass:
381 new_insn = new_prog;
382 fp = prog;
383
384 if (new_insn)
385 *new_insn = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1);
386 new_insn++;
387
388 for (i = 0; i < len; fp++, i++) {
389 struct bpf_insn tmp_insns[6] = { };
390 struct bpf_insn *insn = tmp_insns;
391
392 if (addrs)
393 addrs[i] = new_insn - new_prog;
394
395 switch (fp->code) {
396 /* All arithmetic insns and skb loads map as-is. */
397 case BPF_ALU | BPF_ADD | BPF_X:
398 case BPF_ALU | BPF_ADD | BPF_K:
399 case BPF_ALU | BPF_SUB | BPF_X:
400 case BPF_ALU | BPF_SUB | BPF_K:
401 case BPF_ALU | BPF_AND | BPF_X:
402 case BPF_ALU | BPF_AND | BPF_K:
403 case BPF_ALU | BPF_OR | BPF_X:
404 case BPF_ALU | BPF_OR | BPF_K:
405 case BPF_ALU | BPF_LSH | BPF_X:
406 case BPF_ALU | BPF_LSH | BPF_K:
407 case BPF_ALU | BPF_RSH | BPF_X:
408 case BPF_ALU | BPF_RSH | BPF_K:
409 case BPF_ALU | BPF_XOR | BPF_X:
410 case BPF_ALU | BPF_XOR | BPF_K:
411 case BPF_ALU | BPF_MUL | BPF_X:
412 case BPF_ALU | BPF_MUL | BPF_K:
413 case BPF_ALU | BPF_DIV | BPF_X:
414 case BPF_ALU | BPF_DIV | BPF_K:
415 case BPF_ALU | BPF_MOD | BPF_X:
416 case BPF_ALU | BPF_MOD | BPF_K:
417 case BPF_ALU | BPF_NEG:
418 case BPF_LD | BPF_ABS | BPF_W:
419 case BPF_LD | BPF_ABS | BPF_H:
420 case BPF_LD | BPF_ABS | BPF_B:
421 case BPF_LD | BPF_IND | BPF_W:
422 case BPF_LD | BPF_IND | BPF_H:
423 case BPF_LD | BPF_IND | BPF_B:
424 /* Check for overloaded BPF extension and
425 * directly convert it if found, otherwise
426 * just move on with mapping.
427 */
428 if (BPF_CLASS(fp->code) == BPF_LD &&
429 BPF_MODE(fp->code) == BPF_ABS &&
430 convert_bpf_extensions(fp, &insn))
431 break;
432
433 *insn = BPF_RAW_INSN(fp->code, BPF_REG_A, BPF_REG_X, 0, fp->k);
434 break;
435
436 /* Jump transformation cannot use BPF block macros
437 * everywhere as offset calculation and target updates
438 * require a bit more work than the rest, i.e. jump
439 * opcodes map as-is, but offsets need adjustment.
440 */
441
442 #define BPF_EMIT_JMP \
443 do { \
444 if (target >= len || target < 0) \
445 goto err; \
446 insn->off = addrs ? addrs[target] - addrs[i] - 1 : 0; \
447 /* Adjust pc relative offset for 2nd or 3rd insn. */ \
448 insn->off -= insn - tmp_insns; \
449 } while (0)
450
451 case BPF_JMP | BPF_JA:
452 target = i + fp->k + 1;
453 insn->code = fp->code;
454 BPF_EMIT_JMP;
455 break;
456
457 case BPF_JMP | BPF_JEQ | BPF_K:
458 case BPF_JMP | BPF_JEQ | BPF_X:
459 case BPF_JMP | BPF_JSET | BPF_K:
460 case BPF_JMP | BPF_JSET | BPF_X:
461 case BPF_JMP | BPF_JGT | BPF_K:
462 case BPF_JMP | BPF_JGT | BPF_X:
463 case BPF_JMP | BPF_JGE | BPF_K:
464 case BPF_JMP | BPF_JGE | BPF_X:
465 if (BPF_SRC(fp->code) == BPF_K && (int) fp->k < 0) {
466 /* BPF immediates are signed, zero extend
467 * immediate into tmp register and use it
468 * in compare insn.
469 */
470 *insn++ = BPF_MOV32_IMM(BPF_REG_TMP, fp->k);
471
472 insn->dst_reg = BPF_REG_A;
473 insn->src_reg = BPF_REG_TMP;
474 bpf_src = BPF_X;
475 } else {
476 insn->dst_reg = BPF_REG_A;
477 insn->imm = fp->k;
478 bpf_src = BPF_SRC(fp->code);
479 insn->src_reg = bpf_src == BPF_X ? BPF_REG_X : 0;
480 }
481
482 /* Common case where 'jump_false' is next insn. */
483 if (fp->jf == 0) {
484 insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
485 target = i + fp->jt + 1;
486 BPF_EMIT_JMP;
487 break;
488 }
489
490 /* Convert JEQ into JNE when 'jump_true' is next insn. */
491 if (fp->jt == 0 && BPF_OP(fp->code) == BPF_JEQ) {
492 insn->code = BPF_JMP | BPF_JNE | bpf_src;
493 target = i + fp->jf + 1;
494 BPF_EMIT_JMP;
495 break;
496 }
497
498 /* Other jumps are mapped into two insns: Jxx and JA. */
499 target = i + fp->jt + 1;
500 insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
501 BPF_EMIT_JMP;
502 insn++;
503
504 insn->code = BPF_JMP | BPF_JA;
505 target = i + fp->jf + 1;
506 BPF_EMIT_JMP;
507 break;
508
509 /* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */
510 case BPF_LDX | BPF_MSH | BPF_B:
511 /* tmp = A */
512 *insn++ = BPF_MOV64_REG(BPF_REG_TMP, BPF_REG_A);
513 /* A = BPF_R0 = *(u8 *) (skb->data + K) */
514 *insn++ = BPF_LD_ABS(BPF_B, fp->k);
515 /* A &= 0xf */
516 *insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 0xf);
517 /* A <<= 2 */
518 *insn++ = BPF_ALU32_IMM(BPF_LSH, BPF_REG_A, 2);
519 /* X = A */
520 *insn++ = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
521 /* A = tmp */
522 *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_TMP);
523 break;
524
525 /* RET_K, RET_A are remaped into 2 insns. */
526 case BPF_RET | BPF_A:
527 case BPF_RET | BPF_K:
528 *insn++ = BPF_MOV32_RAW(BPF_RVAL(fp->code) == BPF_K ?
529 BPF_K : BPF_X, BPF_REG_0,
530 BPF_REG_A, fp->k);
531 *insn = BPF_EXIT_INSN();
532 break;
533
534 /* Store to stack. */
535 case BPF_ST:
536 case BPF_STX:
537 *insn = BPF_STX_MEM(BPF_W, BPF_REG_FP, BPF_CLASS(fp->code) ==
538 BPF_ST ? BPF_REG_A : BPF_REG_X,
539 -(BPF_MEMWORDS - fp->k) * 4);
540 break;
541
542 /* Load from stack. */
543 case BPF_LD | BPF_MEM:
544 case BPF_LDX | BPF_MEM:
545 *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
546 BPF_REG_A : BPF_REG_X, BPF_REG_FP,
547 -(BPF_MEMWORDS - fp->k) * 4);
548 break;
549
550 /* A = K or X = K */
551 case BPF_LD | BPF_IMM:
552 case BPF_LDX | BPF_IMM:
553 *insn = BPF_MOV32_IMM(BPF_CLASS(fp->code) == BPF_LD ?
554 BPF_REG_A : BPF_REG_X, fp->k);
555 break;
556
557 /* X = A */
558 case BPF_MISC | BPF_TAX:
559 *insn = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
560 break;
561
562 /* A = X */
563 case BPF_MISC | BPF_TXA:
564 *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_X);
565 break;
566
567 /* A = skb->len or X = skb->len */
568 case BPF_LD | BPF_W | BPF_LEN:
569 case BPF_LDX | BPF_W | BPF_LEN:
570 *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
571 BPF_REG_A : BPF_REG_X, BPF_REG_CTX,
572 offsetof(struct sk_buff, len));
573 break;
574
575 /* Access seccomp_data fields. */
576 case BPF_LDX | BPF_ABS | BPF_W:
577 /* A = *(u32 *) (ctx + K) */
578 *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, fp->k);
579 break;
580
581 /* Unknown instruction. */
582 default:
583 goto err;
584 }
585
586 insn++;
587 if (new_prog)
588 memcpy(new_insn, tmp_insns,
589 sizeof(*insn) * (insn - tmp_insns));
590 new_insn += insn - tmp_insns;
591 }
592
593 if (!new_prog) {
594 /* Only calculating new length. */
595 *new_len = new_insn - new_prog;
596 return 0;
597 }
598
599 pass++;
600 if (new_flen != new_insn - new_prog) {
601 new_flen = new_insn - new_prog;
602 if (pass > 2)
603 goto err;
604 goto do_pass;
605 }
606
607 kfree(addrs);
608 BUG_ON(*new_len != new_flen);
609 return 0;
610 err:
611 kfree(addrs);
612 return -EINVAL;
613 }
614
615 /* Security:
616 *
617 * As we dont want to clear mem[] array for each packet going through
618 * __bpf_prog_run(), we check that filter loaded by user never try to read
619 * a cell if not previously written, and we check all branches to be sure
620 * a malicious user doesn't try to abuse us.
621 */
622 static int check_load_and_stores(const struct sock_filter *filter, int flen)
623 {
624 u16 *masks, memvalid = 0; /* One bit per cell, 16 cells */
625 int pc, ret = 0;
626
627 BUILD_BUG_ON(BPF_MEMWORDS > 16);
628
629 masks = kmalloc_array(flen, sizeof(*masks), GFP_KERNEL);
630 if (!masks)
631 return -ENOMEM;
632
633 memset(masks, 0xff, flen * sizeof(*masks));
634
635 for (pc = 0; pc < flen; pc++) {
636 memvalid &= masks[pc];
637
638 switch (filter[pc].code) {
639 case BPF_ST:
640 case BPF_STX:
641 memvalid |= (1 << filter[pc].k);
642 break;
643 case BPF_LD | BPF_MEM:
644 case BPF_LDX | BPF_MEM:
645 if (!(memvalid & (1 << filter[pc].k))) {
646 ret = -EINVAL;
647 goto error;
648 }
649 break;
650 case BPF_JMP | BPF_JA:
651 /* A jump must set masks on target */
652 masks[pc + 1 + filter[pc].k] &= memvalid;
653 memvalid = ~0;
654 break;
655 case BPF_JMP | BPF_JEQ | BPF_K:
656 case BPF_JMP | BPF_JEQ | BPF_X:
657 case BPF_JMP | BPF_JGE | BPF_K:
658 case BPF_JMP | BPF_JGE | BPF_X:
659 case BPF_JMP | BPF_JGT | BPF_K:
660 case BPF_JMP | BPF_JGT | BPF_X:
661 case BPF_JMP | BPF_JSET | BPF_K:
662 case BPF_JMP | BPF_JSET | BPF_X:
663 /* A jump must set masks on targets */
664 masks[pc + 1 + filter[pc].jt] &= memvalid;
665 masks[pc + 1 + filter[pc].jf] &= memvalid;
666 memvalid = ~0;
667 break;
668 }
669 }
670 error:
671 kfree(masks);
672 return ret;
673 }
674
675 static bool chk_code_allowed(u16 code_to_probe)
676 {
677 static const bool codes[] = {
678 /* 32 bit ALU operations */
679 [BPF_ALU | BPF_ADD | BPF_K] = true,
680 [BPF_ALU | BPF_ADD | BPF_X] = true,
681 [BPF_ALU | BPF_SUB | BPF_K] = true,
682 [BPF_ALU | BPF_SUB | BPF_X] = true,
683 [BPF_ALU | BPF_MUL | BPF_K] = true,
684 [BPF_ALU | BPF_MUL | BPF_X] = true,
685 [BPF_ALU | BPF_DIV | BPF_K] = true,
686 [BPF_ALU | BPF_DIV | BPF_X] = true,
687 [BPF_ALU | BPF_MOD | BPF_K] = true,
688 [BPF_ALU | BPF_MOD | BPF_X] = true,
689 [BPF_ALU | BPF_AND | BPF_K] = true,
690 [BPF_ALU | BPF_AND | BPF_X] = true,
691 [BPF_ALU | BPF_OR | BPF_K] = true,
692 [BPF_ALU | BPF_OR | BPF_X] = true,
693 [BPF_ALU | BPF_XOR | BPF_K] = true,
694 [BPF_ALU | BPF_XOR | BPF_X] = true,
695 [BPF_ALU | BPF_LSH | BPF_K] = true,
696 [BPF_ALU | BPF_LSH | BPF_X] = true,
697 [BPF_ALU | BPF_RSH | BPF_K] = true,
698 [BPF_ALU | BPF_RSH | BPF_X] = true,
699 [BPF_ALU | BPF_NEG] = true,
700 /* Load instructions */
701 [BPF_LD | BPF_W | BPF_ABS] = true,
702 [BPF_LD | BPF_H | BPF_ABS] = true,
703 [BPF_LD | BPF_B | BPF_ABS] = true,
704 [BPF_LD | BPF_W | BPF_LEN] = true,
705 [BPF_LD | BPF_W | BPF_IND] = true,
706 [BPF_LD | BPF_H | BPF_IND] = true,
707 [BPF_LD | BPF_B | BPF_IND] = true,
708 [BPF_LD | BPF_IMM] = true,
709 [BPF_LD | BPF_MEM] = true,
710 [BPF_LDX | BPF_W | BPF_LEN] = true,
711 [BPF_LDX | BPF_B | BPF_MSH] = true,
712 [BPF_LDX | BPF_IMM] = true,
713 [BPF_LDX | BPF_MEM] = true,
714 /* Store instructions */
715 [BPF_ST] = true,
716 [BPF_STX] = true,
717 /* Misc instructions */
718 [BPF_MISC | BPF_TAX] = true,
719 [BPF_MISC | BPF_TXA] = true,
720 /* Return instructions */
721 [BPF_RET | BPF_K] = true,
722 [BPF_RET | BPF_A] = true,
723 /* Jump instructions */
724 [BPF_JMP | BPF_JA] = true,
725 [BPF_JMP | BPF_JEQ | BPF_K] = true,
726 [BPF_JMP | BPF_JEQ | BPF_X] = true,
727 [BPF_JMP | BPF_JGE | BPF_K] = true,
728 [BPF_JMP | BPF_JGE | BPF_X] = true,
729 [BPF_JMP | BPF_JGT | BPF_K] = true,
730 [BPF_JMP | BPF_JGT | BPF_X] = true,
731 [BPF_JMP | BPF_JSET | BPF_K] = true,
732 [BPF_JMP | BPF_JSET | BPF_X] = true,
733 };
734
735 if (code_to_probe >= ARRAY_SIZE(codes))
736 return false;
737
738 return codes[code_to_probe];
739 }
740
741 /**
742 * bpf_check_classic - verify socket filter code
743 * @filter: filter to verify
744 * @flen: length of filter
745 *
746 * Check the user's filter code. If we let some ugly
747 * filter code slip through kaboom! The filter must contain
748 * no references or jumps that are out of range, no illegal
749 * instructions, and must end with a RET instruction.
750 *
751 * All jumps are forward as they are not signed.
752 *
753 * Returns 0 if the rule set is legal or -EINVAL if not.
754 */
755 static int bpf_check_classic(const struct sock_filter *filter,
756 unsigned int flen)
757 {
758 bool anc_found;
759 int pc;
760
761 if (flen == 0 || flen > BPF_MAXINSNS)
762 return -EINVAL;
763
764 /* Check the filter code now */
765 for (pc = 0; pc < flen; pc++) {
766 const struct sock_filter *ftest = &filter[pc];
767
768 /* May we actually operate on this code? */
769 if (!chk_code_allowed(ftest->code))
770 return -EINVAL;
771
772 /* Some instructions need special checks */
773 switch (ftest->code) {
774 case BPF_ALU | BPF_DIV | BPF_K:
775 case BPF_ALU | BPF_MOD | BPF_K:
776 /* Check for division by zero */
777 if (ftest->k == 0)
778 return -EINVAL;
779 break;
780 case BPF_LD | BPF_MEM:
781 case BPF_LDX | BPF_MEM:
782 case BPF_ST:
783 case BPF_STX:
784 /* Check for invalid memory addresses */
785 if (ftest->k >= BPF_MEMWORDS)
786 return -EINVAL;
787 break;
788 case BPF_JMP | BPF_JA:
789 /* Note, the large ftest->k might cause loops.
790 * Compare this with conditional jumps below,
791 * where offsets are limited. --ANK (981016)
792 */
793 if (ftest->k >= (unsigned int)(flen - pc - 1))
794 return -EINVAL;
795 break;
796 case BPF_JMP | BPF_JEQ | BPF_K:
797 case BPF_JMP | BPF_JEQ | BPF_X:
798 case BPF_JMP | BPF_JGE | BPF_K:
799 case BPF_JMP | BPF_JGE | BPF_X:
800 case BPF_JMP | BPF_JGT | BPF_K:
801 case BPF_JMP | BPF_JGT | BPF_X:
802 case BPF_JMP | BPF_JSET | BPF_K:
803 case BPF_JMP | BPF_JSET | BPF_X:
804 /* Both conditionals must be safe */
805 if (pc + ftest->jt + 1 >= flen ||
806 pc + ftest->jf + 1 >= flen)
807 return -EINVAL;
808 break;
809 case BPF_LD | BPF_W | BPF_ABS:
810 case BPF_LD | BPF_H | BPF_ABS:
811 case BPF_LD | BPF_B | BPF_ABS:
812 anc_found = false;
813 if (bpf_anc_helper(ftest) & BPF_ANC)
814 anc_found = true;
815 /* Ancillary operation unknown or unsupported */
816 if (anc_found == false && ftest->k >= SKF_AD_OFF)
817 return -EINVAL;
818 }
819 }
820
821 /* Last instruction must be a RET code */
822 switch (filter[flen - 1].code) {
823 case BPF_RET | BPF_K:
824 case BPF_RET | BPF_A:
825 return check_load_and_stores(filter, flen);
826 }
827
828 return -EINVAL;
829 }
830
831 static int bpf_prog_store_orig_filter(struct bpf_prog *fp,
832 const struct sock_fprog *fprog)
833 {
834 unsigned int fsize = bpf_classic_proglen(fprog);
835 struct sock_fprog_kern *fkprog;
836
837 fp->orig_prog = kmalloc(sizeof(*fkprog), GFP_KERNEL);
838 if (!fp->orig_prog)
839 return -ENOMEM;
840
841 fkprog = fp->orig_prog;
842 fkprog->len = fprog->len;
843
844 fkprog->filter = kmemdup(fp->insns, fsize,
845 GFP_KERNEL | __GFP_NOWARN);
846 if (!fkprog->filter) {
847 kfree(fp->orig_prog);
848 return -ENOMEM;
849 }
850
851 return 0;
852 }
853
854 static void bpf_release_orig_filter(struct bpf_prog *fp)
855 {
856 struct sock_fprog_kern *fprog = fp->orig_prog;
857
858 if (fprog) {
859 kfree(fprog->filter);
860 kfree(fprog);
861 }
862 }
863
864 static void __bpf_prog_release(struct bpf_prog *prog)
865 {
866 if (prog->type == BPF_PROG_TYPE_SOCKET_FILTER) {
867 bpf_prog_put(prog);
868 } else {
869 bpf_release_orig_filter(prog);
870 bpf_prog_free(prog);
871 }
872 }
873
874 static void __sk_filter_release(struct sk_filter *fp)
875 {
876 __bpf_prog_release(fp->prog);
877 kfree(fp);
878 }
879
880 /**
881 * sk_filter_release_rcu - Release a socket filter by rcu_head
882 * @rcu: rcu_head that contains the sk_filter to free
883 */
884 static void sk_filter_release_rcu(struct rcu_head *rcu)
885 {
886 struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu);
887
888 __sk_filter_release(fp);
889 }
890
891 /**
892 * sk_filter_release - release a socket filter
893 * @fp: filter to remove
894 *
895 * Remove a filter from a socket and release its resources.
896 */
897 static void sk_filter_release(struct sk_filter *fp)
898 {
899 if (atomic_dec_and_test(&fp->refcnt))
900 call_rcu(&fp->rcu, sk_filter_release_rcu);
901 }
902
903 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
904 {
905 u32 filter_size = bpf_prog_size(fp->prog->len);
906
907 atomic_sub(filter_size, &sk->sk_omem_alloc);
908 sk_filter_release(fp);
909 }
910
911 /* try to charge the socket memory if there is space available
912 * return true on success
913 */
914 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp)
915 {
916 u32 filter_size = bpf_prog_size(fp->prog->len);
917
918 /* same check as in sock_kmalloc() */
919 if (filter_size <= sysctl_optmem_max &&
920 atomic_read(&sk->sk_omem_alloc) + filter_size < sysctl_optmem_max) {
921 atomic_inc(&fp->refcnt);
922 atomic_add(filter_size, &sk->sk_omem_alloc);
923 return true;
924 }
925 return false;
926 }
927
928 static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp)
929 {
930 struct sock_filter *old_prog;
931 struct bpf_prog *old_fp;
932 int err, new_len, old_len = fp->len;
933
934 /* We are free to overwrite insns et al right here as it
935 * won't be used at this point in time anymore internally
936 * after the migration to the internal BPF instruction
937 * representation.
938 */
939 BUILD_BUG_ON(sizeof(struct sock_filter) !=
940 sizeof(struct bpf_insn));
941
942 /* Conversion cannot happen on overlapping memory areas,
943 * so we need to keep the user BPF around until the 2nd
944 * pass. At this time, the user BPF is stored in fp->insns.
945 */
946 old_prog = kmemdup(fp->insns, old_len * sizeof(struct sock_filter),
947 GFP_KERNEL | __GFP_NOWARN);
948 if (!old_prog) {
949 err = -ENOMEM;
950 goto out_err;
951 }
952
953 /* 1st pass: calculate the new program length. */
954 err = bpf_convert_filter(old_prog, old_len, NULL, &new_len);
955 if (err)
956 goto out_err_free;
957
958 /* Expand fp for appending the new filter representation. */
959 old_fp = fp;
960 fp = bpf_prog_realloc(old_fp, bpf_prog_size(new_len), 0);
961 if (!fp) {
962 /* The old_fp is still around in case we couldn't
963 * allocate new memory, so uncharge on that one.
964 */
965 fp = old_fp;
966 err = -ENOMEM;
967 goto out_err_free;
968 }
969
970 fp->len = new_len;
971
972 /* 2nd pass: remap sock_filter insns into bpf_insn insns. */
973 err = bpf_convert_filter(old_prog, old_len, fp->insnsi, &new_len);
974 if (err)
975 /* 2nd bpf_convert_filter() can fail only if it fails
976 * to allocate memory, remapping must succeed. Note,
977 * that at this time old_fp has already been released
978 * by krealloc().
979 */
980 goto out_err_free;
981
982 bpf_prog_select_runtime(fp);
983
984 kfree(old_prog);
985 return fp;
986
987 out_err_free:
988 kfree(old_prog);
989 out_err:
990 __bpf_prog_release(fp);
991 return ERR_PTR(err);
992 }
993
994 static struct bpf_prog *bpf_prepare_filter(struct bpf_prog *fp,
995 bpf_aux_classic_check_t trans)
996 {
997 int err;
998
999 fp->bpf_func = NULL;
1000 fp->jited = 0;
1001
1002 err = bpf_check_classic(fp->insns, fp->len);
1003 if (err) {
1004 __bpf_prog_release(fp);
1005 return ERR_PTR(err);
1006 }
1007
1008 /* There might be additional checks and transformations
1009 * needed on classic filters, f.e. in case of seccomp.
1010 */
1011 if (trans) {
1012 err = trans(fp->insns, fp->len);
1013 if (err) {
1014 __bpf_prog_release(fp);
1015 return ERR_PTR(err);
1016 }
1017 }
1018
1019 /* Probe if we can JIT compile the filter and if so, do
1020 * the compilation of the filter.
1021 */
1022 bpf_jit_compile(fp);
1023
1024 /* JIT compiler couldn't process this filter, so do the
1025 * internal BPF translation for the optimized interpreter.
1026 */
1027 if (!fp->jited)
1028 fp = bpf_migrate_filter(fp);
1029
1030 return fp;
1031 }
1032
1033 /**
1034 * bpf_prog_create - create an unattached filter
1035 * @pfp: the unattached filter that is created
1036 * @fprog: the filter program
1037 *
1038 * Create a filter independent of any socket. We first run some
1039 * sanity checks on it to make sure it does not explode on us later.
1040 * If an error occurs or there is insufficient memory for the filter
1041 * a negative errno code is returned. On success the return is zero.
1042 */
1043 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog)
1044 {
1045 unsigned int fsize = bpf_classic_proglen(fprog);
1046 struct bpf_prog *fp;
1047
1048 /* Make sure new filter is there and in the right amounts. */
1049 if (fprog->filter == NULL)
1050 return -EINVAL;
1051
1052 fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0);
1053 if (!fp)
1054 return -ENOMEM;
1055
1056 memcpy(fp->insns, fprog->filter, fsize);
1057
1058 fp->len = fprog->len;
1059 /* Since unattached filters are not copied back to user
1060 * space through sk_get_filter(), we do not need to hold
1061 * a copy here, and can spare us the work.
1062 */
1063 fp->orig_prog = NULL;
1064
1065 /* bpf_prepare_filter() already takes care of freeing
1066 * memory in case something goes wrong.
1067 */
1068 fp = bpf_prepare_filter(fp, NULL);
1069 if (IS_ERR(fp))
1070 return PTR_ERR(fp);
1071
1072 *pfp = fp;
1073 return 0;
1074 }
1075 EXPORT_SYMBOL_GPL(bpf_prog_create);
1076
1077 /**
1078 * bpf_prog_create_from_user - create an unattached filter from user buffer
1079 * @pfp: the unattached filter that is created
1080 * @fprog: the filter program
1081 * @trans: post-classic verifier transformation handler
1082 * @save_orig: save classic BPF program
1083 *
1084 * This function effectively does the same as bpf_prog_create(), only
1085 * that it builds up its insns buffer from user space provided buffer.
1086 * It also allows for passing a bpf_aux_classic_check_t handler.
1087 */
1088 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
1089 bpf_aux_classic_check_t trans, bool save_orig)
1090 {
1091 unsigned int fsize = bpf_classic_proglen(fprog);
1092 struct bpf_prog *fp;
1093 int err;
1094
1095 /* Make sure new filter is there and in the right amounts. */
1096 if (fprog->filter == NULL)
1097 return -EINVAL;
1098
1099 fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0);
1100 if (!fp)
1101 return -ENOMEM;
1102
1103 if (copy_from_user(fp->insns, fprog->filter, fsize)) {
1104 __bpf_prog_free(fp);
1105 return -EFAULT;
1106 }
1107
1108 fp->len = fprog->len;
1109 fp->orig_prog = NULL;
1110
1111 if (save_orig) {
1112 err = bpf_prog_store_orig_filter(fp, fprog);
1113 if (err) {
1114 __bpf_prog_free(fp);
1115 return -ENOMEM;
1116 }
1117 }
1118
1119 /* bpf_prepare_filter() already takes care of freeing
1120 * memory in case something goes wrong.
1121 */
1122 fp = bpf_prepare_filter(fp, trans);
1123 if (IS_ERR(fp))
1124 return PTR_ERR(fp);
1125
1126 *pfp = fp;
1127 return 0;
1128 }
1129 EXPORT_SYMBOL_GPL(bpf_prog_create_from_user);
1130
1131 void bpf_prog_destroy(struct bpf_prog *fp)
1132 {
1133 __bpf_prog_release(fp);
1134 }
1135 EXPORT_SYMBOL_GPL(bpf_prog_destroy);
1136
1137 static int __sk_attach_prog(struct bpf_prog *prog, struct sock *sk)
1138 {
1139 struct sk_filter *fp, *old_fp;
1140
1141 fp = kmalloc(sizeof(*fp), GFP_KERNEL);
1142 if (!fp)
1143 return -ENOMEM;
1144
1145 fp->prog = prog;
1146 atomic_set(&fp->refcnt, 0);
1147
1148 if (!sk_filter_charge(sk, fp)) {
1149 kfree(fp);
1150 return -ENOMEM;
1151 }
1152
1153 old_fp = rcu_dereference_protected(sk->sk_filter,
1154 sock_owned_by_user(sk));
1155 rcu_assign_pointer(sk->sk_filter, fp);
1156
1157 if (old_fp)
1158 sk_filter_uncharge(sk, old_fp);
1159
1160 return 0;
1161 }
1162
1163 /**
1164 * sk_attach_filter - attach a socket filter
1165 * @fprog: the filter program
1166 * @sk: the socket to use
1167 *
1168 * Attach the user's filter code. We first run some sanity checks on
1169 * it to make sure it does not explode on us later. If an error
1170 * occurs or there is insufficient memory for the filter a negative
1171 * errno code is returned. On success the return is zero.
1172 */
1173 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
1174 {
1175 unsigned int fsize = bpf_classic_proglen(fprog);
1176 unsigned int bpf_fsize = bpf_prog_size(fprog->len);
1177 struct bpf_prog *prog;
1178 int err;
1179
1180 if (sock_flag(sk, SOCK_FILTER_LOCKED))
1181 return -EPERM;
1182
1183 /* Make sure new filter is there and in the right amounts. */
1184 if (fprog->filter == NULL)
1185 return -EINVAL;
1186
1187 prog = bpf_prog_alloc(bpf_fsize, 0);
1188 if (!prog)
1189 return -ENOMEM;
1190
1191 if (copy_from_user(prog->insns, fprog->filter, fsize)) {
1192 __bpf_prog_free(prog);
1193 return -EFAULT;
1194 }
1195
1196 prog->len = fprog->len;
1197
1198 err = bpf_prog_store_orig_filter(prog, fprog);
1199 if (err) {
1200 __bpf_prog_free(prog);
1201 return -ENOMEM;
1202 }
1203
1204 /* bpf_prepare_filter() already takes care of freeing
1205 * memory in case something goes wrong.
1206 */
1207 prog = bpf_prepare_filter(prog, NULL);
1208 if (IS_ERR(prog))
1209 return PTR_ERR(prog);
1210
1211 err = __sk_attach_prog(prog, sk);
1212 if (err < 0) {
1213 __bpf_prog_release(prog);
1214 return err;
1215 }
1216
1217 return 0;
1218 }
1219 EXPORT_SYMBOL_GPL(sk_attach_filter);
1220
1221 int sk_attach_bpf(u32 ufd, struct sock *sk)
1222 {
1223 struct bpf_prog *prog;
1224 int err;
1225
1226 if (sock_flag(sk, SOCK_FILTER_LOCKED))
1227 return -EPERM;
1228
1229 prog = bpf_prog_get(ufd);
1230 if (IS_ERR(prog))
1231 return PTR_ERR(prog);
1232
1233 if (prog->type != BPF_PROG_TYPE_SOCKET_FILTER) {
1234 bpf_prog_put(prog);
1235 return -EINVAL;
1236 }
1237
1238 err = __sk_attach_prog(prog, sk);
1239 if (err < 0) {
1240 bpf_prog_put(prog);
1241 return err;
1242 }
1243
1244 return 0;
1245 }
1246
1247 #define BPF_RECOMPUTE_CSUM(flags) ((flags) & 1)
1248
1249 static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags)
1250 {
1251 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1252 int offset = (int) r2;
1253 void *from = (void *) (long) r3;
1254 unsigned int len = (unsigned int) r4;
1255 char buf[16];
1256 void *ptr;
1257
1258 /* bpf verifier guarantees that:
1259 * 'from' pointer points to bpf program stack
1260 * 'len' bytes of it were initialized
1261 * 'len' > 0
1262 * 'skb' is a valid pointer to 'struct sk_buff'
1263 *
1264 * so check for invalid 'offset' and too large 'len'
1265 */
1266 if (unlikely((u32) offset > 0xffff || len > sizeof(buf)))
1267 return -EFAULT;
1268
1269 if (unlikely(skb_cloned(skb) &&
1270 !skb_clone_writable(skb, offset + len)))
1271 return -EFAULT;
1272
1273 ptr = skb_header_pointer(skb, offset, len, buf);
1274 if (unlikely(!ptr))
1275 return -EFAULT;
1276
1277 if (BPF_RECOMPUTE_CSUM(flags))
1278 skb_postpull_rcsum(skb, ptr, len);
1279
1280 memcpy(ptr, from, len);
1281
1282 if (ptr == buf)
1283 /* skb_store_bits cannot return -EFAULT here */
1284 skb_store_bits(skb, offset, ptr, len);
1285
1286 if (BPF_RECOMPUTE_CSUM(flags) && skb->ip_summed == CHECKSUM_COMPLETE)
1287 skb->csum = csum_add(skb->csum, csum_partial(ptr, len, 0));
1288 return 0;
1289 }
1290
1291 const struct bpf_func_proto bpf_skb_store_bytes_proto = {
1292 .func = bpf_skb_store_bytes,
1293 .gpl_only = false,
1294 .ret_type = RET_INTEGER,
1295 .arg1_type = ARG_PTR_TO_CTX,
1296 .arg2_type = ARG_ANYTHING,
1297 .arg3_type = ARG_PTR_TO_STACK,
1298 .arg4_type = ARG_CONST_STACK_SIZE,
1299 .arg5_type = ARG_ANYTHING,
1300 };
1301
1302 #define BPF_HEADER_FIELD_SIZE(flags) ((flags) & 0x0f)
1303 #define BPF_IS_PSEUDO_HEADER(flags) ((flags) & 0x10)
1304
1305 static u64 bpf_l3_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags)
1306 {
1307 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1308 int offset = (int) r2;
1309 __sum16 sum, *ptr;
1310
1311 if (unlikely((u32) offset > 0xffff))
1312 return -EFAULT;
1313
1314 if (unlikely(skb_cloned(skb) &&
1315 !skb_clone_writable(skb, offset + sizeof(sum))))
1316 return -EFAULT;
1317
1318 ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum);
1319 if (unlikely(!ptr))
1320 return -EFAULT;
1321
1322 switch (BPF_HEADER_FIELD_SIZE(flags)) {
1323 case 2:
1324 csum_replace2(ptr, from, to);
1325 break;
1326 case 4:
1327 csum_replace4(ptr, from, to);
1328 break;
1329 default:
1330 return -EINVAL;
1331 }
1332
1333 if (ptr == &sum)
1334 /* skb_store_bits guaranteed to not return -EFAULT here */
1335 skb_store_bits(skb, offset, ptr, sizeof(sum));
1336
1337 return 0;
1338 }
1339
1340 const struct bpf_func_proto bpf_l3_csum_replace_proto = {
1341 .func = bpf_l3_csum_replace,
1342 .gpl_only = false,
1343 .ret_type = RET_INTEGER,
1344 .arg1_type = ARG_PTR_TO_CTX,
1345 .arg2_type = ARG_ANYTHING,
1346 .arg3_type = ARG_ANYTHING,
1347 .arg4_type = ARG_ANYTHING,
1348 .arg5_type = ARG_ANYTHING,
1349 };
1350
1351 static u64 bpf_l4_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags)
1352 {
1353 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1354 bool is_pseudo = !!BPF_IS_PSEUDO_HEADER(flags);
1355 int offset = (int) r2;
1356 __sum16 sum, *ptr;
1357
1358 if (unlikely((u32) offset > 0xffff))
1359 return -EFAULT;
1360
1361 if (unlikely(skb_cloned(skb) &&
1362 !skb_clone_writable(skb, offset + sizeof(sum))))
1363 return -EFAULT;
1364
1365 ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum);
1366 if (unlikely(!ptr))
1367 return -EFAULT;
1368
1369 switch (BPF_HEADER_FIELD_SIZE(flags)) {
1370 case 2:
1371 inet_proto_csum_replace2(ptr, skb, from, to, is_pseudo);
1372 break;
1373 case 4:
1374 inet_proto_csum_replace4(ptr, skb, from, to, is_pseudo);
1375 break;
1376 default:
1377 return -EINVAL;
1378 }
1379
1380 if (ptr == &sum)
1381 /* skb_store_bits guaranteed to not return -EFAULT here */
1382 skb_store_bits(skb, offset, ptr, sizeof(sum));
1383
1384 return 0;
1385 }
1386
1387 const struct bpf_func_proto bpf_l4_csum_replace_proto = {
1388 .func = bpf_l4_csum_replace,
1389 .gpl_only = false,
1390 .ret_type = RET_INTEGER,
1391 .arg1_type = ARG_PTR_TO_CTX,
1392 .arg2_type = ARG_ANYTHING,
1393 .arg3_type = ARG_ANYTHING,
1394 .arg4_type = ARG_ANYTHING,
1395 .arg5_type = ARG_ANYTHING,
1396 };
1397
1398 #define BPF_IS_REDIRECT_INGRESS(flags) ((flags) & 1)
1399
1400 static u64 bpf_clone_redirect(u64 r1, u64 ifindex, u64 flags, u64 r4, u64 r5)
1401 {
1402 struct sk_buff *skb = (struct sk_buff *) (long) r1, *skb2;
1403 struct net_device *dev;
1404
1405 dev = dev_get_by_index_rcu(dev_net(skb->dev), ifindex);
1406 if (unlikely(!dev))
1407 return -EINVAL;
1408
1409 skb2 = skb_clone(skb, GFP_ATOMIC);
1410 if (unlikely(!skb2))
1411 return -ENOMEM;
1412
1413 if (BPF_IS_REDIRECT_INGRESS(flags))
1414 return dev_forward_skb(dev, skb2);
1415
1416 skb2->dev = dev;
1417 return dev_queue_xmit(skb2);
1418 }
1419
1420 const struct bpf_func_proto bpf_clone_redirect_proto = {
1421 .func = bpf_clone_redirect,
1422 .gpl_only = false,
1423 .ret_type = RET_INTEGER,
1424 .arg1_type = ARG_PTR_TO_CTX,
1425 .arg2_type = ARG_ANYTHING,
1426 .arg3_type = ARG_ANYTHING,
1427 };
1428
1429 struct redirect_info {
1430 u32 ifindex;
1431 u32 flags;
1432 };
1433
1434 static DEFINE_PER_CPU(struct redirect_info, redirect_info);
1435 static u64 bpf_redirect(u64 ifindex, u64 flags, u64 r3, u64 r4, u64 r5)
1436 {
1437 struct redirect_info *ri = this_cpu_ptr(&redirect_info);
1438
1439 ri->ifindex = ifindex;
1440 ri->flags = flags;
1441 return TC_ACT_REDIRECT;
1442 }
1443
1444 int skb_do_redirect(struct sk_buff *skb)
1445 {
1446 struct redirect_info *ri = this_cpu_ptr(&redirect_info);
1447 struct net_device *dev;
1448
1449 dev = dev_get_by_index_rcu(dev_net(skb->dev), ri->ifindex);
1450 ri->ifindex = 0;
1451 if (unlikely(!dev)) {
1452 kfree_skb(skb);
1453 return -EINVAL;
1454 }
1455
1456 if (BPF_IS_REDIRECT_INGRESS(ri->flags))
1457 return dev_forward_skb(dev, skb);
1458
1459 skb->dev = dev;
1460 skb_sender_cpu_clear(skb);
1461 return dev_queue_xmit(skb);
1462 }
1463
1464 const struct bpf_func_proto bpf_redirect_proto = {
1465 .func = bpf_redirect,
1466 .gpl_only = false,
1467 .ret_type = RET_INTEGER,
1468 .arg1_type = ARG_ANYTHING,
1469 .arg2_type = ARG_ANYTHING,
1470 };
1471
1472 static u64 bpf_get_cgroup_classid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1473 {
1474 return task_get_classid((struct sk_buff *) (unsigned long) r1);
1475 }
1476
1477 static const struct bpf_func_proto bpf_get_cgroup_classid_proto = {
1478 .func = bpf_get_cgroup_classid,
1479 .gpl_only = false,
1480 .ret_type = RET_INTEGER,
1481 .arg1_type = ARG_PTR_TO_CTX,
1482 };
1483
1484 static u64 bpf_get_route_realm(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1485 {
1486 #ifdef CONFIG_IP_ROUTE_CLASSID
1487 const struct dst_entry *dst;
1488
1489 dst = skb_dst((struct sk_buff *) (unsigned long) r1);
1490 if (dst)
1491 return dst->tclassid;
1492 #endif
1493 return 0;
1494 }
1495
1496 static const struct bpf_func_proto bpf_get_route_realm_proto = {
1497 .func = bpf_get_route_realm,
1498 .gpl_only = false,
1499 .ret_type = RET_INTEGER,
1500 .arg1_type = ARG_PTR_TO_CTX,
1501 };
1502
1503 static u64 bpf_skb_vlan_push(u64 r1, u64 r2, u64 vlan_tci, u64 r4, u64 r5)
1504 {
1505 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1506 __be16 vlan_proto = (__force __be16) r2;
1507
1508 if (unlikely(vlan_proto != htons(ETH_P_8021Q) &&
1509 vlan_proto != htons(ETH_P_8021AD)))
1510 vlan_proto = htons(ETH_P_8021Q);
1511
1512 return skb_vlan_push(skb, vlan_proto, vlan_tci);
1513 }
1514
1515 const struct bpf_func_proto bpf_skb_vlan_push_proto = {
1516 .func = bpf_skb_vlan_push,
1517 .gpl_only = false,
1518 .ret_type = RET_INTEGER,
1519 .arg1_type = ARG_PTR_TO_CTX,
1520 .arg2_type = ARG_ANYTHING,
1521 .arg3_type = ARG_ANYTHING,
1522 };
1523 EXPORT_SYMBOL_GPL(bpf_skb_vlan_push_proto);
1524
1525 static u64 bpf_skb_vlan_pop(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1526 {
1527 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1528
1529 return skb_vlan_pop(skb);
1530 }
1531
1532 const struct bpf_func_proto bpf_skb_vlan_pop_proto = {
1533 .func = bpf_skb_vlan_pop,
1534 .gpl_only = false,
1535 .ret_type = RET_INTEGER,
1536 .arg1_type = ARG_PTR_TO_CTX,
1537 };
1538 EXPORT_SYMBOL_GPL(bpf_skb_vlan_pop_proto);
1539
1540 bool bpf_helper_changes_skb_data(void *func)
1541 {
1542 if (func == bpf_skb_vlan_push)
1543 return true;
1544 if (func == bpf_skb_vlan_pop)
1545 return true;
1546 return false;
1547 }
1548
1549 static u64 bpf_skb_get_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5)
1550 {
1551 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1552 struct bpf_tunnel_key *to = (struct bpf_tunnel_key *) (long) r2;
1553 struct ip_tunnel_info *info = skb_tunnel_info(skb);
1554
1555 if (unlikely(size != sizeof(struct bpf_tunnel_key) || flags || !info))
1556 return -EINVAL;
1557 if (ip_tunnel_info_af(info) != AF_INET)
1558 return -EINVAL;
1559
1560 to->tunnel_id = be64_to_cpu(info->key.tun_id);
1561 to->remote_ipv4 = be32_to_cpu(info->key.u.ipv4.src);
1562
1563 return 0;
1564 }
1565
1566 const struct bpf_func_proto bpf_skb_get_tunnel_key_proto = {
1567 .func = bpf_skb_get_tunnel_key,
1568 .gpl_only = false,
1569 .ret_type = RET_INTEGER,
1570 .arg1_type = ARG_PTR_TO_CTX,
1571 .arg2_type = ARG_PTR_TO_STACK,
1572 .arg3_type = ARG_CONST_STACK_SIZE,
1573 .arg4_type = ARG_ANYTHING,
1574 };
1575
1576 static struct metadata_dst __percpu *md_dst;
1577
1578 static u64 bpf_skb_set_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5)
1579 {
1580 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1581 struct bpf_tunnel_key *from = (struct bpf_tunnel_key *) (long) r2;
1582 struct metadata_dst *md = this_cpu_ptr(md_dst);
1583 struct ip_tunnel_info *info;
1584
1585 if (unlikely(size != sizeof(struct bpf_tunnel_key) || flags))
1586 return -EINVAL;
1587
1588 skb_dst_drop(skb);
1589 dst_hold((struct dst_entry *) md);
1590 skb_dst_set(skb, (struct dst_entry *) md);
1591
1592 info = &md->u.tun_info;
1593 info->mode = IP_TUNNEL_INFO_TX;
1594 info->key.tun_flags = TUNNEL_KEY;
1595 info->key.tun_id = cpu_to_be64(from->tunnel_id);
1596 info->key.u.ipv4.dst = cpu_to_be32(from->remote_ipv4);
1597
1598 return 0;
1599 }
1600
1601 const struct bpf_func_proto bpf_skb_set_tunnel_key_proto = {
1602 .func = bpf_skb_set_tunnel_key,
1603 .gpl_only = false,
1604 .ret_type = RET_INTEGER,
1605 .arg1_type = ARG_PTR_TO_CTX,
1606 .arg2_type = ARG_PTR_TO_STACK,
1607 .arg3_type = ARG_CONST_STACK_SIZE,
1608 .arg4_type = ARG_ANYTHING,
1609 };
1610
1611 static const struct bpf_func_proto *bpf_get_skb_set_tunnel_key_proto(void)
1612 {
1613 if (!md_dst) {
1614 /* race is not possible, since it's called from
1615 * verifier that is holding verifier mutex
1616 */
1617 md_dst = metadata_dst_alloc_percpu(0, GFP_KERNEL);
1618 if (!md_dst)
1619 return NULL;
1620 }
1621 return &bpf_skb_set_tunnel_key_proto;
1622 }
1623
1624 static const struct bpf_func_proto *
1625 sk_filter_func_proto(enum bpf_func_id func_id)
1626 {
1627 switch (func_id) {
1628 case BPF_FUNC_map_lookup_elem:
1629 return &bpf_map_lookup_elem_proto;
1630 case BPF_FUNC_map_update_elem:
1631 return &bpf_map_update_elem_proto;
1632 case BPF_FUNC_map_delete_elem:
1633 return &bpf_map_delete_elem_proto;
1634 case BPF_FUNC_get_prandom_u32:
1635 return &bpf_get_prandom_u32_proto;
1636 case BPF_FUNC_get_smp_processor_id:
1637 return &bpf_get_smp_processor_id_proto;
1638 case BPF_FUNC_tail_call:
1639 return &bpf_tail_call_proto;
1640 case BPF_FUNC_ktime_get_ns:
1641 return &bpf_ktime_get_ns_proto;
1642 case BPF_FUNC_trace_printk:
1643 return bpf_get_trace_printk_proto();
1644 default:
1645 return NULL;
1646 }
1647 }
1648
1649 static const struct bpf_func_proto *
1650 tc_cls_act_func_proto(enum bpf_func_id func_id)
1651 {
1652 switch (func_id) {
1653 case BPF_FUNC_skb_store_bytes:
1654 return &bpf_skb_store_bytes_proto;
1655 case BPF_FUNC_l3_csum_replace:
1656 return &bpf_l3_csum_replace_proto;
1657 case BPF_FUNC_l4_csum_replace:
1658 return &bpf_l4_csum_replace_proto;
1659 case BPF_FUNC_clone_redirect:
1660 return &bpf_clone_redirect_proto;
1661 case BPF_FUNC_get_cgroup_classid:
1662 return &bpf_get_cgroup_classid_proto;
1663 case BPF_FUNC_skb_vlan_push:
1664 return &bpf_skb_vlan_push_proto;
1665 case BPF_FUNC_skb_vlan_pop:
1666 return &bpf_skb_vlan_pop_proto;
1667 case BPF_FUNC_skb_get_tunnel_key:
1668 return &bpf_skb_get_tunnel_key_proto;
1669 case BPF_FUNC_skb_set_tunnel_key:
1670 return bpf_get_skb_set_tunnel_key_proto();
1671 case BPF_FUNC_redirect:
1672 return &bpf_redirect_proto;
1673 case BPF_FUNC_get_route_realm:
1674 return &bpf_get_route_realm_proto;
1675 default:
1676 return sk_filter_func_proto(func_id);
1677 }
1678 }
1679
1680 static bool __is_valid_access(int off, int size, enum bpf_access_type type)
1681 {
1682 /* check bounds */
1683 if (off < 0 || off >= sizeof(struct __sk_buff))
1684 return false;
1685
1686 /* disallow misaligned access */
1687 if (off % size != 0)
1688 return false;
1689
1690 /* all __sk_buff fields are __u32 */
1691 if (size != 4)
1692 return false;
1693
1694 return true;
1695 }
1696
1697 static bool sk_filter_is_valid_access(int off, int size,
1698 enum bpf_access_type type)
1699 {
1700 if (off == offsetof(struct __sk_buff, tc_classid))
1701 return false;
1702
1703 if (type == BPF_WRITE) {
1704 switch (off) {
1705 case offsetof(struct __sk_buff, cb[0]) ...
1706 offsetof(struct __sk_buff, cb[4]):
1707 break;
1708 default:
1709 return false;
1710 }
1711 }
1712
1713 return __is_valid_access(off, size, type);
1714 }
1715
1716 static bool tc_cls_act_is_valid_access(int off, int size,
1717 enum bpf_access_type type)
1718 {
1719 if (off == offsetof(struct __sk_buff, tc_classid))
1720 return type == BPF_WRITE ? true : false;
1721
1722 if (type == BPF_WRITE) {
1723 switch (off) {
1724 case offsetof(struct __sk_buff, mark):
1725 case offsetof(struct __sk_buff, tc_index):
1726 case offsetof(struct __sk_buff, priority):
1727 case offsetof(struct __sk_buff, cb[0]) ...
1728 offsetof(struct __sk_buff, cb[4]):
1729 break;
1730 default:
1731 return false;
1732 }
1733 }
1734 return __is_valid_access(off, size, type);
1735 }
1736
1737 static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg,
1738 int src_reg, int ctx_off,
1739 struct bpf_insn *insn_buf,
1740 struct bpf_prog *prog)
1741 {
1742 struct bpf_insn *insn = insn_buf;
1743
1744 switch (ctx_off) {
1745 case offsetof(struct __sk_buff, len):
1746 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
1747
1748 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
1749 offsetof(struct sk_buff, len));
1750 break;
1751
1752 case offsetof(struct __sk_buff, protocol):
1753 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
1754
1755 *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
1756 offsetof(struct sk_buff, protocol));
1757 break;
1758
1759 case offsetof(struct __sk_buff, vlan_proto):
1760 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
1761
1762 *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
1763 offsetof(struct sk_buff, vlan_proto));
1764 break;
1765
1766 case offsetof(struct __sk_buff, priority):
1767 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, priority) != 4);
1768
1769 if (type == BPF_WRITE)
1770 *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg,
1771 offsetof(struct sk_buff, priority));
1772 else
1773 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
1774 offsetof(struct sk_buff, priority));
1775 break;
1776
1777 case offsetof(struct __sk_buff, ingress_ifindex):
1778 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, skb_iif) != 4);
1779
1780 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
1781 offsetof(struct sk_buff, skb_iif));
1782 break;
1783
1784 case offsetof(struct __sk_buff, ifindex):
1785 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
1786
1787 *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)),
1788 dst_reg, src_reg,
1789 offsetof(struct sk_buff, dev));
1790 *insn++ = BPF_JMP_IMM(BPF_JEQ, dst_reg, 0, 1);
1791 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, dst_reg,
1792 offsetof(struct net_device, ifindex));
1793 break;
1794
1795 case offsetof(struct __sk_buff, hash):
1796 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
1797
1798 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
1799 offsetof(struct sk_buff, hash));
1800 break;
1801
1802 case offsetof(struct __sk_buff, mark):
1803 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
1804
1805 if (type == BPF_WRITE)
1806 *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg,
1807 offsetof(struct sk_buff, mark));
1808 else
1809 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
1810 offsetof(struct sk_buff, mark));
1811 break;
1812
1813 case offsetof(struct __sk_buff, pkt_type):
1814 return convert_skb_access(SKF_AD_PKTTYPE, dst_reg, src_reg, insn);
1815
1816 case offsetof(struct __sk_buff, queue_mapping):
1817 return convert_skb_access(SKF_AD_QUEUE, dst_reg, src_reg, insn);
1818
1819 case offsetof(struct __sk_buff, vlan_present):
1820 return convert_skb_access(SKF_AD_VLAN_TAG_PRESENT,
1821 dst_reg, src_reg, insn);
1822
1823 case offsetof(struct __sk_buff, vlan_tci):
1824 return convert_skb_access(SKF_AD_VLAN_TAG,
1825 dst_reg, src_reg, insn);
1826
1827 case offsetof(struct __sk_buff, cb[0]) ...
1828 offsetof(struct __sk_buff, cb[4]):
1829 BUILD_BUG_ON(FIELD_SIZEOF(struct qdisc_skb_cb, data) < 20);
1830
1831 prog->cb_access = 1;
1832 ctx_off -= offsetof(struct __sk_buff, cb[0]);
1833 ctx_off += offsetof(struct sk_buff, cb);
1834 ctx_off += offsetof(struct qdisc_skb_cb, data);
1835 if (type == BPF_WRITE)
1836 *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg, ctx_off);
1837 else
1838 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, ctx_off);
1839 break;
1840
1841 case offsetof(struct __sk_buff, tc_classid):
1842 ctx_off -= offsetof(struct __sk_buff, tc_classid);
1843 ctx_off += offsetof(struct sk_buff, cb);
1844 ctx_off += offsetof(struct qdisc_skb_cb, tc_classid);
1845 WARN_ON(type != BPF_WRITE);
1846 *insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg, ctx_off);
1847 break;
1848
1849 case offsetof(struct __sk_buff, tc_index):
1850 #ifdef CONFIG_NET_SCHED
1851 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, tc_index) != 2);
1852
1853 if (type == BPF_WRITE)
1854 *insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg,
1855 offsetof(struct sk_buff, tc_index));
1856 else
1857 *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
1858 offsetof(struct sk_buff, tc_index));
1859 break;
1860 #else
1861 if (type == BPF_WRITE)
1862 *insn++ = BPF_MOV64_REG(dst_reg, dst_reg);
1863 else
1864 *insn++ = BPF_MOV64_IMM(dst_reg, 0);
1865 break;
1866 #endif
1867 }
1868
1869 return insn - insn_buf;
1870 }
1871
1872 static const struct bpf_verifier_ops sk_filter_ops = {
1873 .get_func_proto = sk_filter_func_proto,
1874 .is_valid_access = sk_filter_is_valid_access,
1875 .convert_ctx_access = bpf_net_convert_ctx_access,
1876 };
1877
1878 static const struct bpf_verifier_ops tc_cls_act_ops = {
1879 .get_func_proto = tc_cls_act_func_proto,
1880 .is_valid_access = tc_cls_act_is_valid_access,
1881 .convert_ctx_access = bpf_net_convert_ctx_access,
1882 };
1883
1884 static struct bpf_prog_type_list sk_filter_type __read_mostly = {
1885 .ops = &sk_filter_ops,
1886 .type = BPF_PROG_TYPE_SOCKET_FILTER,
1887 };
1888
1889 static struct bpf_prog_type_list sched_cls_type __read_mostly = {
1890 .ops = &tc_cls_act_ops,
1891 .type = BPF_PROG_TYPE_SCHED_CLS,
1892 };
1893
1894 static struct bpf_prog_type_list sched_act_type __read_mostly = {
1895 .ops = &tc_cls_act_ops,
1896 .type = BPF_PROG_TYPE_SCHED_ACT,
1897 };
1898
1899 static int __init register_sk_filter_ops(void)
1900 {
1901 bpf_register_prog_type(&sk_filter_type);
1902 bpf_register_prog_type(&sched_cls_type);
1903 bpf_register_prog_type(&sched_act_type);
1904
1905 return 0;
1906 }
1907 late_initcall(register_sk_filter_ops);
1908
1909 int sk_detach_filter(struct sock *sk)
1910 {
1911 int ret = -ENOENT;
1912 struct sk_filter *filter;
1913
1914 if (sock_flag(sk, SOCK_FILTER_LOCKED))
1915 return -EPERM;
1916
1917 filter = rcu_dereference_protected(sk->sk_filter,
1918 sock_owned_by_user(sk));
1919 if (filter) {
1920 RCU_INIT_POINTER(sk->sk_filter, NULL);
1921 sk_filter_uncharge(sk, filter);
1922 ret = 0;
1923 }
1924
1925 return ret;
1926 }
1927 EXPORT_SYMBOL_GPL(sk_detach_filter);
1928
1929 int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf,
1930 unsigned int len)
1931 {
1932 struct sock_fprog_kern *fprog;
1933 struct sk_filter *filter;
1934 int ret = 0;
1935
1936 lock_sock(sk);
1937 filter = rcu_dereference_protected(sk->sk_filter,
1938 sock_owned_by_user(sk));
1939 if (!filter)
1940 goto out;
1941
1942 /* We're copying the filter that has been originally attached,
1943 * so no conversion/decode needed anymore.
1944 */
1945 fprog = filter->prog->orig_prog;
1946
1947 ret = fprog->len;
1948 if (!len)
1949 /* User space only enquires number of filter blocks. */
1950 goto out;
1951
1952 ret = -EINVAL;
1953 if (len < fprog->len)
1954 goto out;
1955
1956 ret = -EFAULT;
1957 if (copy_to_user(ubuf, fprog->filter, bpf_classic_proglen(fprog)))
1958 goto out;
1959
1960 /* Instead of bytes, the API requests to return the number
1961 * of filter blocks.
1962 */
1963 ret = fprog->len;
1964 out:
1965 release_sock(sk);
1966 return ret;
1967 }
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