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Merge tag 'usb-serial-4.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/johan...
[deliverable/linux.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 #include <net/sock_reuseport.h>
54
55 /**
56 * sk_filter - run a packet through a socket filter
57 * @sk: sock associated with &sk_buff
58 * @skb: buffer to filter
59 *
60 * Run the eBPF program and then cut skb->data to correct size returned by
61 * the program. If pkt_len is 0 we toss packet. If skb->len is smaller
62 * than pkt_len we keep whole skb->data. This is the socket level
63 * wrapper to BPF_PROG_RUN. It returns 0 if the packet should
64 * be accepted or -EPERM if the packet should be tossed.
65 *
66 */
67 int sk_filter(struct sock *sk, struct sk_buff *skb)
68 {
69 int err;
70 struct sk_filter *filter;
71
72 /*
73 * If the skb was allocated from pfmemalloc reserves, only
74 * allow SOCK_MEMALLOC sockets to use it as this socket is
75 * helping free memory
76 */
77 if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
78 return -ENOMEM;
79
80 err = security_sock_rcv_skb(sk, skb);
81 if (err)
82 return err;
83
84 rcu_read_lock();
85 filter = rcu_dereference(sk->sk_filter);
86 if (filter) {
87 unsigned int pkt_len = bpf_prog_run_save_cb(filter->prog, skb);
88
89 err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
90 }
91 rcu_read_unlock();
92
93 return err;
94 }
95 EXPORT_SYMBOL(sk_filter);
96
97 static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
98 {
99 return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
100 }
101
102 static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
103 {
104 struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
105 struct nlattr *nla;
106
107 if (skb_is_nonlinear(skb))
108 return 0;
109
110 if (skb->len < sizeof(struct nlattr))
111 return 0;
112
113 if (a > skb->len - sizeof(struct nlattr))
114 return 0;
115
116 nla = nla_find((struct nlattr *) &skb->data[a], skb->len - a, x);
117 if (nla)
118 return (void *) nla - (void *) skb->data;
119
120 return 0;
121 }
122
123 static u64 __skb_get_nlattr_nest(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
124 {
125 struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
126 struct nlattr *nla;
127
128 if (skb_is_nonlinear(skb))
129 return 0;
130
131 if (skb->len < sizeof(struct nlattr))
132 return 0;
133
134 if (a > skb->len - sizeof(struct nlattr))
135 return 0;
136
137 nla = (struct nlattr *) &skb->data[a];
138 if (nla->nla_len > skb->len - a)
139 return 0;
140
141 nla = nla_find_nested(nla, x);
142 if (nla)
143 return (void *) nla - (void *) skb->data;
144
145 return 0;
146 }
147
148 static u64 __get_raw_cpu_id(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
149 {
150 return raw_smp_processor_id();
151 }
152
153 static u32 convert_skb_access(int skb_field, int dst_reg, int src_reg,
154 struct bpf_insn *insn_buf)
155 {
156 struct bpf_insn *insn = insn_buf;
157
158 switch (skb_field) {
159 case SKF_AD_MARK:
160 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
161
162 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
163 offsetof(struct sk_buff, mark));
164 break;
165
166 case SKF_AD_PKTTYPE:
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);
171 #endif
172 break;
173
174 case SKF_AD_QUEUE:
175 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
176
177 *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
178 offsetof(struct sk_buff, queue_mapping));
179 break;
180
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);
185
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,
191 ~VLAN_TAG_PRESENT);
192 } else {
193 /* dst_reg >>= 12 */
194 *insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 12);
195 /* dst_reg &= 1 */
196 *insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, 1);
197 }
198 break;
199 }
200
201 return insn - insn_buf;
202 }
203
204 static bool convert_bpf_extensions(struct sock_filter *fp,
205 struct bpf_insn **insnp)
206 {
207 struct bpf_insn *insn = *insnp;
208 u32 cnt;
209
210 switch (fp->k) {
211 case SKF_AD_OFF + SKF_AD_PROTOCOL:
212 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
213
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);
219 break;
220
221 case SKF_AD_OFF + SKF_AD_PKTTYPE:
222 cnt = convert_skb_access(SKF_AD_PKTTYPE, BPF_REG_A, BPF_REG_CTX, insn);
223 insn += cnt - 1;
224 break;
225
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);
231
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));
241 else
242 *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_TMP,
243 offsetof(struct net_device, type));
244 break;
245
246 case SKF_AD_OFF + SKF_AD_MARK:
247 cnt = convert_skb_access(SKF_AD_MARK, BPF_REG_A, BPF_REG_CTX, insn);
248 insn += cnt - 1;
249 break;
250
251 case SKF_AD_OFF + SKF_AD_RXHASH:
252 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
253
254 *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX,
255 offsetof(struct sk_buff, hash));
256 break;
257
258 case SKF_AD_OFF + SKF_AD_QUEUE:
259 cnt = convert_skb_access(SKF_AD_QUEUE, BPF_REG_A, BPF_REG_CTX, insn);
260 insn += cnt - 1;
261 break;
262
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);
266 insn += cnt - 1;
267 break;
268
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);
272 insn += cnt - 1;
273 break;
274
275 case SKF_AD_OFF + SKF_AD_VLAN_TPID:
276 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
277
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);
283 break;
284
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:
290 /* arg1 = CTX */
291 *insn++ = BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_CTX);
292 /* arg2 = A */
293 *insn++ = BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_A);
294 /* arg3 = X */
295 *insn++ = BPF_MOV64_REG(BPF_REG_ARG3, BPF_REG_X);
296 /* Emit call(arg1=CTX, arg2=A, arg3=X) */
297 switch (fp->k) {
298 case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
299 *insn = BPF_EMIT_CALL(__skb_get_pay_offset);
300 break;
301 case SKF_AD_OFF + SKF_AD_NLATTR:
302 *insn = BPF_EMIT_CALL(__skb_get_nlattr);
303 break;
304 case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
305 *insn = BPF_EMIT_CALL(__skb_get_nlattr_nest);
306 break;
307 case SKF_AD_OFF + SKF_AD_CPU:
308 *insn = BPF_EMIT_CALL(__get_raw_cpu_id);
309 break;
310 case SKF_AD_OFF + SKF_AD_RANDOM:
311 *insn = BPF_EMIT_CALL(bpf_user_rnd_u32);
312 bpf_user_rnd_init_once();
313 break;
314 }
315 break;
316
317 case SKF_AD_OFF + SKF_AD_ALU_XOR_X:
318 /* A ^= X */
319 *insn = BPF_ALU32_REG(BPF_XOR, BPF_REG_A, BPF_REG_X);
320 break;
321
322 default:
323 /* This is just a dummy call to avoid letting the compiler
324 * evict __bpf_call_base() as an optimization. Placed here
325 * where no-one bothers.
326 */
327 BUG_ON(__bpf_call_base(0, 0, 0, 0, 0) != 0);
328 return false;
329 }
330
331 *insnp = insn;
332 return true;
333 }
334
335 /**
336 * bpf_convert_filter - convert filter program
337 * @prog: the user passed filter program
338 * @len: the length of the user passed filter program
339 * @new_prog: buffer where converted program will be stored
340 * @new_len: pointer to store length of converted program
341 *
342 * Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style.
343 * Conversion workflow:
344 *
345 * 1) First pass for calculating the new program length:
346 * bpf_convert_filter(old_prog, old_len, NULL, &new_len)
347 *
348 * 2) 2nd pass to remap in two passes: 1st pass finds new
349 * jump offsets, 2nd pass remapping:
350 * new_prog = kmalloc(sizeof(struct bpf_insn) * new_len);
351 * bpf_convert_filter(old_prog, old_len, new_prog, &new_len);
352 */
353 static int bpf_convert_filter(struct sock_filter *prog, int len,
354 struct bpf_insn *new_prog, int *new_len)
355 {
356 int new_flen = 0, pass = 0, target, i;
357 struct bpf_insn *new_insn;
358 struct sock_filter *fp;
359 int *addrs = NULL;
360 u8 bpf_src;
361
362 BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK);
363 BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
364
365 if (len <= 0 || len > BPF_MAXINSNS)
366 return -EINVAL;
367
368 if (new_prog) {
369 addrs = kcalloc(len, sizeof(*addrs),
370 GFP_KERNEL | __GFP_NOWARN);
371 if (!addrs)
372 return -ENOMEM;
373 }
374
375 do_pass:
376 new_insn = new_prog;
377 fp = prog;
378
379 /* Classic BPF related prologue emission. */
380 if (new_insn) {
381 /* Classic BPF expects A and X to be reset first. These need
382 * to be guaranteed to be the first two instructions.
383 */
384 *new_insn++ = BPF_ALU64_REG(BPF_XOR, BPF_REG_A, BPF_REG_A);
385 *new_insn++ = BPF_ALU64_REG(BPF_XOR, BPF_REG_X, BPF_REG_X);
386
387 /* All programs must keep CTX in callee saved BPF_REG_CTX.
388 * In eBPF case it's done by the compiler, here we need to
389 * do this ourself. Initial CTX is present in BPF_REG_ARG1.
390 */
391 *new_insn++ = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1);
392 } else {
393 new_insn += 3;
394 }
395
396 for (i = 0; i < len; fp++, i++) {
397 struct bpf_insn tmp_insns[6] = { };
398 struct bpf_insn *insn = tmp_insns;
399
400 if (addrs)
401 addrs[i] = new_insn - new_prog;
402
403 switch (fp->code) {
404 /* All arithmetic insns and skb loads map as-is. */
405 case BPF_ALU | BPF_ADD | BPF_X:
406 case BPF_ALU | BPF_ADD | BPF_K:
407 case BPF_ALU | BPF_SUB | BPF_X:
408 case BPF_ALU | BPF_SUB | BPF_K:
409 case BPF_ALU | BPF_AND | BPF_X:
410 case BPF_ALU | BPF_AND | BPF_K:
411 case BPF_ALU | BPF_OR | BPF_X:
412 case BPF_ALU | BPF_OR | BPF_K:
413 case BPF_ALU | BPF_LSH | BPF_X:
414 case BPF_ALU | BPF_LSH | BPF_K:
415 case BPF_ALU | BPF_RSH | BPF_X:
416 case BPF_ALU | BPF_RSH | BPF_K:
417 case BPF_ALU | BPF_XOR | BPF_X:
418 case BPF_ALU | BPF_XOR | BPF_K:
419 case BPF_ALU | BPF_MUL | BPF_X:
420 case BPF_ALU | BPF_MUL | BPF_K:
421 case BPF_ALU | BPF_DIV | BPF_X:
422 case BPF_ALU | BPF_DIV | BPF_K:
423 case BPF_ALU | BPF_MOD | BPF_X:
424 case BPF_ALU | BPF_MOD | BPF_K:
425 case BPF_ALU | BPF_NEG:
426 case BPF_LD | BPF_ABS | BPF_W:
427 case BPF_LD | BPF_ABS | BPF_H:
428 case BPF_LD | BPF_ABS | BPF_B:
429 case BPF_LD | BPF_IND | BPF_W:
430 case BPF_LD | BPF_IND | BPF_H:
431 case BPF_LD | BPF_IND | BPF_B:
432 /* Check for overloaded BPF extension and
433 * directly convert it if found, otherwise
434 * just move on with mapping.
435 */
436 if (BPF_CLASS(fp->code) == BPF_LD &&
437 BPF_MODE(fp->code) == BPF_ABS &&
438 convert_bpf_extensions(fp, &insn))
439 break;
440
441 *insn = BPF_RAW_INSN(fp->code, BPF_REG_A, BPF_REG_X, 0, fp->k);
442 break;
443
444 /* Jump transformation cannot use BPF block macros
445 * everywhere as offset calculation and target updates
446 * require a bit more work than the rest, i.e. jump
447 * opcodes map as-is, but offsets need adjustment.
448 */
449
450 #define BPF_EMIT_JMP \
451 do { \
452 if (target >= len || target < 0) \
453 goto err; \
454 insn->off = addrs ? addrs[target] - addrs[i] - 1 : 0; \
455 /* Adjust pc relative offset for 2nd or 3rd insn. */ \
456 insn->off -= insn - tmp_insns; \
457 } while (0)
458
459 case BPF_JMP | BPF_JA:
460 target = i + fp->k + 1;
461 insn->code = fp->code;
462 BPF_EMIT_JMP;
463 break;
464
465 case BPF_JMP | BPF_JEQ | BPF_K:
466 case BPF_JMP | BPF_JEQ | BPF_X:
467 case BPF_JMP | BPF_JSET | BPF_K:
468 case BPF_JMP | BPF_JSET | BPF_X:
469 case BPF_JMP | BPF_JGT | BPF_K:
470 case BPF_JMP | BPF_JGT | BPF_X:
471 case BPF_JMP | BPF_JGE | BPF_K:
472 case BPF_JMP | BPF_JGE | BPF_X:
473 if (BPF_SRC(fp->code) == BPF_K && (int) fp->k < 0) {
474 /* BPF immediates are signed, zero extend
475 * immediate into tmp register and use it
476 * in compare insn.
477 */
478 *insn++ = BPF_MOV32_IMM(BPF_REG_TMP, fp->k);
479
480 insn->dst_reg = BPF_REG_A;
481 insn->src_reg = BPF_REG_TMP;
482 bpf_src = BPF_X;
483 } else {
484 insn->dst_reg = BPF_REG_A;
485 insn->imm = fp->k;
486 bpf_src = BPF_SRC(fp->code);
487 insn->src_reg = bpf_src == BPF_X ? BPF_REG_X : 0;
488 }
489
490 /* Common case where 'jump_false' is next insn. */
491 if (fp->jf == 0) {
492 insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
493 target = i + fp->jt + 1;
494 BPF_EMIT_JMP;
495 break;
496 }
497
498 /* Convert JEQ into JNE when 'jump_true' is next insn. */
499 if (fp->jt == 0 && BPF_OP(fp->code) == BPF_JEQ) {
500 insn->code = BPF_JMP | BPF_JNE | bpf_src;
501 target = i + fp->jf + 1;
502 BPF_EMIT_JMP;
503 break;
504 }
505
506 /* Other jumps are mapped into two insns: Jxx and JA. */
507 target = i + fp->jt + 1;
508 insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
509 BPF_EMIT_JMP;
510 insn++;
511
512 insn->code = BPF_JMP | BPF_JA;
513 target = i + fp->jf + 1;
514 BPF_EMIT_JMP;
515 break;
516
517 /* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */
518 case BPF_LDX | BPF_MSH | BPF_B:
519 /* tmp = A */
520 *insn++ = BPF_MOV64_REG(BPF_REG_TMP, BPF_REG_A);
521 /* A = BPF_R0 = *(u8 *) (skb->data + K) */
522 *insn++ = BPF_LD_ABS(BPF_B, fp->k);
523 /* A &= 0xf */
524 *insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 0xf);
525 /* A <<= 2 */
526 *insn++ = BPF_ALU32_IMM(BPF_LSH, BPF_REG_A, 2);
527 /* X = A */
528 *insn++ = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
529 /* A = tmp */
530 *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_TMP);
531 break;
532
533 /* RET_K is remaped into 2 insns. RET_A case doesn't need an
534 * extra mov as BPF_REG_0 is already mapped into BPF_REG_A.
535 */
536 case BPF_RET | BPF_A:
537 case BPF_RET | BPF_K:
538 if (BPF_RVAL(fp->code) == BPF_K)
539 *insn++ = BPF_MOV32_RAW(BPF_K, BPF_REG_0,
540 0, fp->k);
541 *insn = BPF_EXIT_INSN();
542 break;
543
544 /* Store to stack. */
545 case BPF_ST:
546 case BPF_STX:
547 *insn = BPF_STX_MEM(BPF_W, BPF_REG_FP, BPF_CLASS(fp->code) ==
548 BPF_ST ? BPF_REG_A : BPF_REG_X,
549 -(BPF_MEMWORDS - fp->k) * 4);
550 break;
551
552 /* Load from stack. */
553 case BPF_LD | BPF_MEM:
554 case BPF_LDX | BPF_MEM:
555 *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
556 BPF_REG_A : BPF_REG_X, BPF_REG_FP,
557 -(BPF_MEMWORDS - fp->k) * 4);
558 break;
559
560 /* A = K or X = K */
561 case BPF_LD | BPF_IMM:
562 case BPF_LDX | BPF_IMM:
563 *insn = BPF_MOV32_IMM(BPF_CLASS(fp->code) == BPF_LD ?
564 BPF_REG_A : BPF_REG_X, fp->k);
565 break;
566
567 /* X = A */
568 case BPF_MISC | BPF_TAX:
569 *insn = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
570 break;
571
572 /* A = X */
573 case BPF_MISC | BPF_TXA:
574 *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_X);
575 break;
576
577 /* A = skb->len or X = skb->len */
578 case BPF_LD | BPF_W | BPF_LEN:
579 case BPF_LDX | BPF_W | BPF_LEN:
580 *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
581 BPF_REG_A : BPF_REG_X, BPF_REG_CTX,
582 offsetof(struct sk_buff, len));
583 break;
584
585 /* Access seccomp_data fields. */
586 case BPF_LDX | BPF_ABS | BPF_W:
587 /* A = *(u32 *) (ctx + K) */
588 *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, fp->k);
589 break;
590
591 /* Unknown instruction. */
592 default:
593 goto err;
594 }
595
596 insn++;
597 if (new_prog)
598 memcpy(new_insn, tmp_insns,
599 sizeof(*insn) * (insn - tmp_insns));
600 new_insn += insn - tmp_insns;
601 }
602
603 if (!new_prog) {
604 /* Only calculating new length. */
605 *new_len = new_insn - new_prog;
606 return 0;
607 }
608
609 pass++;
610 if (new_flen != new_insn - new_prog) {
611 new_flen = new_insn - new_prog;
612 if (pass > 2)
613 goto err;
614 goto do_pass;
615 }
616
617 kfree(addrs);
618 BUG_ON(*new_len != new_flen);
619 return 0;
620 err:
621 kfree(addrs);
622 return -EINVAL;
623 }
624
625 /* Security:
626 *
627 * As we dont want to clear mem[] array for each packet going through
628 * __bpf_prog_run(), we check that filter loaded by user never try to read
629 * a cell if not previously written, and we check all branches to be sure
630 * a malicious user doesn't try to abuse us.
631 */
632 static int check_load_and_stores(const struct sock_filter *filter, int flen)
633 {
634 u16 *masks, memvalid = 0; /* One bit per cell, 16 cells */
635 int pc, ret = 0;
636
637 BUILD_BUG_ON(BPF_MEMWORDS > 16);
638
639 masks = kmalloc_array(flen, sizeof(*masks), GFP_KERNEL);
640 if (!masks)
641 return -ENOMEM;
642
643 memset(masks, 0xff, flen * sizeof(*masks));
644
645 for (pc = 0; pc < flen; pc++) {
646 memvalid &= masks[pc];
647
648 switch (filter[pc].code) {
649 case BPF_ST:
650 case BPF_STX:
651 memvalid |= (1 << filter[pc].k);
652 break;
653 case BPF_LD | BPF_MEM:
654 case BPF_LDX | BPF_MEM:
655 if (!(memvalid & (1 << filter[pc].k))) {
656 ret = -EINVAL;
657 goto error;
658 }
659 break;
660 case BPF_JMP | BPF_JA:
661 /* A jump must set masks on target */
662 masks[pc + 1 + filter[pc].k] &= memvalid;
663 memvalid = ~0;
664 break;
665 case BPF_JMP | BPF_JEQ | BPF_K:
666 case BPF_JMP | BPF_JEQ | BPF_X:
667 case BPF_JMP | BPF_JGE | BPF_K:
668 case BPF_JMP | BPF_JGE | BPF_X:
669 case BPF_JMP | BPF_JGT | BPF_K:
670 case BPF_JMP | BPF_JGT | BPF_X:
671 case BPF_JMP | BPF_JSET | BPF_K:
672 case BPF_JMP | BPF_JSET | BPF_X:
673 /* A jump must set masks on targets */
674 masks[pc + 1 + filter[pc].jt] &= memvalid;
675 masks[pc + 1 + filter[pc].jf] &= memvalid;
676 memvalid = ~0;
677 break;
678 }
679 }
680 error:
681 kfree(masks);
682 return ret;
683 }
684
685 static bool chk_code_allowed(u16 code_to_probe)
686 {
687 static const bool codes[] = {
688 /* 32 bit ALU operations */
689 [BPF_ALU | BPF_ADD | BPF_K] = true,
690 [BPF_ALU | BPF_ADD | BPF_X] = true,
691 [BPF_ALU | BPF_SUB | BPF_K] = true,
692 [BPF_ALU | BPF_SUB | BPF_X] = true,
693 [BPF_ALU | BPF_MUL | BPF_K] = true,
694 [BPF_ALU | BPF_MUL | BPF_X] = true,
695 [BPF_ALU | BPF_DIV | BPF_K] = true,
696 [BPF_ALU | BPF_DIV | BPF_X] = true,
697 [BPF_ALU | BPF_MOD | BPF_K] = true,
698 [BPF_ALU | BPF_MOD | BPF_X] = true,
699 [BPF_ALU | BPF_AND | BPF_K] = true,
700 [BPF_ALU | BPF_AND | BPF_X] = true,
701 [BPF_ALU | BPF_OR | BPF_K] = true,
702 [BPF_ALU | BPF_OR | BPF_X] = true,
703 [BPF_ALU | BPF_XOR | BPF_K] = true,
704 [BPF_ALU | BPF_XOR | BPF_X] = true,
705 [BPF_ALU | BPF_LSH | BPF_K] = true,
706 [BPF_ALU | BPF_LSH | BPF_X] = true,
707 [BPF_ALU | BPF_RSH | BPF_K] = true,
708 [BPF_ALU | BPF_RSH | BPF_X] = true,
709 [BPF_ALU | BPF_NEG] = true,
710 /* Load instructions */
711 [BPF_LD | BPF_W | BPF_ABS] = true,
712 [BPF_LD | BPF_H | BPF_ABS] = true,
713 [BPF_LD | BPF_B | BPF_ABS] = true,
714 [BPF_LD | BPF_W | BPF_LEN] = true,
715 [BPF_LD | BPF_W | BPF_IND] = true,
716 [BPF_LD | BPF_H | BPF_IND] = true,
717 [BPF_LD | BPF_B | BPF_IND] = true,
718 [BPF_LD | BPF_IMM] = true,
719 [BPF_LD | BPF_MEM] = true,
720 [BPF_LDX | BPF_W | BPF_LEN] = true,
721 [BPF_LDX | BPF_B | BPF_MSH] = true,
722 [BPF_LDX | BPF_IMM] = true,
723 [BPF_LDX | BPF_MEM] = true,
724 /* Store instructions */
725 [BPF_ST] = true,
726 [BPF_STX] = true,
727 /* Misc instructions */
728 [BPF_MISC | BPF_TAX] = true,
729 [BPF_MISC | BPF_TXA] = true,
730 /* Return instructions */
731 [BPF_RET | BPF_K] = true,
732 [BPF_RET | BPF_A] = true,
733 /* Jump instructions */
734 [BPF_JMP | BPF_JA] = true,
735 [BPF_JMP | BPF_JEQ | BPF_K] = true,
736 [BPF_JMP | BPF_JEQ | BPF_X] = true,
737 [BPF_JMP | BPF_JGE | BPF_K] = true,
738 [BPF_JMP | BPF_JGE | BPF_X] = true,
739 [BPF_JMP | BPF_JGT | BPF_K] = true,
740 [BPF_JMP | BPF_JGT | BPF_X] = true,
741 [BPF_JMP | BPF_JSET | BPF_K] = true,
742 [BPF_JMP | BPF_JSET | BPF_X] = true,
743 };
744
745 if (code_to_probe >= ARRAY_SIZE(codes))
746 return false;
747
748 return codes[code_to_probe];
749 }
750
751 /**
752 * bpf_check_classic - verify socket filter code
753 * @filter: filter to verify
754 * @flen: length of filter
755 *
756 * Check the user's filter code. If we let some ugly
757 * filter code slip through kaboom! The filter must contain
758 * no references or jumps that are out of range, no illegal
759 * instructions, and must end with a RET instruction.
760 *
761 * All jumps are forward as they are not signed.
762 *
763 * Returns 0 if the rule set is legal or -EINVAL if not.
764 */
765 static int bpf_check_classic(const struct sock_filter *filter,
766 unsigned int flen)
767 {
768 bool anc_found;
769 int pc;
770
771 if (flen == 0 || flen > BPF_MAXINSNS)
772 return -EINVAL;
773
774 /* Check the filter code now */
775 for (pc = 0; pc < flen; pc++) {
776 const struct sock_filter *ftest = &filter[pc];
777
778 /* May we actually operate on this code? */
779 if (!chk_code_allowed(ftest->code))
780 return -EINVAL;
781
782 /* Some instructions need special checks */
783 switch (ftest->code) {
784 case BPF_ALU | BPF_DIV | BPF_K:
785 case BPF_ALU | BPF_MOD | BPF_K:
786 /* Check for division by zero */
787 if (ftest->k == 0)
788 return -EINVAL;
789 break;
790 case BPF_ALU | BPF_LSH | BPF_K:
791 case BPF_ALU | BPF_RSH | BPF_K:
792 if (ftest->k >= 32)
793 return -EINVAL;
794 break;
795 case BPF_LD | BPF_MEM:
796 case BPF_LDX | BPF_MEM:
797 case BPF_ST:
798 case BPF_STX:
799 /* Check for invalid memory addresses */
800 if (ftest->k >= BPF_MEMWORDS)
801 return -EINVAL;
802 break;
803 case BPF_JMP | BPF_JA:
804 /* Note, the large ftest->k might cause loops.
805 * Compare this with conditional jumps below,
806 * where offsets are limited. --ANK (981016)
807 */
808 if (ftest->k >= (unsigned int)(flen - pc - 1))
809 return -EINVAL;
810 break;
811 case BPF_JMP | BPF_JEQ | BPF_K:
812 case BPF_JMP | BPF_JEQ | BPF_X:
813 case BPF_JMP | BPF_JGE | BPF_K:
814 case BPF_JMP | BPF_JGE | BPF_X:
815 case BPF_JMP | BPF_JGT | BPF_K:
816 case BPF_JMP | BPF_JGT | BPF_X:
817 case BPF_JMP | BPF_JSET | BPF_K:
818 case BPF_JMP | BPF_JSET | BPF_X:
819 /* Both conditionals must be safe */
820 if (pc + ftest->jt + 1 >= flen ||
821 pc + ftest->jf + 1 >= flen)
822 return -EINVAL;
823 break;
824 case BPF_LD | BPF_W | BPF_ABS:
825 case BPF_LD | BPF_H | BPF_ABS:
826 case BPF_LD | BPF_B | BPF_ABS:
827 anc_found = false;
828 if (bpf_anc_helper(ftest) & BPF_ANC)
829 anc_found = true;
830 /* Ancillary operation unknown or unsupported */
831 if (anc_found == false && ftest->k >= SKF_AD_OFF)
832 return -EINVAL;
833 }
834 }
835
836 /* Last instruction must be a RET code */
837 switch (filter[flen - 1].code) {
838 case BPF_RET | BPF_K:
839 case BPF_RET | BPF_A:
840 return check_load_and_stores(filter, flen);
841 }
842
843 return -EINVAL;
844 }
845
846 static int bpf_prog_store_orig_filter(struct bpf_prog *fp,
847 const struct sock_fprog *fprog)
848 {
849 unsigned int fsize = bpf_classic_proglen(fprog);
850 struct sock_fprog_kern *fkprog;
851
852 fp->orig_prog = kmalloc(sizeof(*fkprog), GFP_KERNEL);
853 if (!fp->orig_prog)
854 return -ENOMEM;
855
856 fkprog = fp->orig_prog;
857 fkprog->len = fprog->len;
858
859 fkprog->filter = kmemdup(fp->insns, fsize,
860 GFP_KERNEL | __GFP_NOWARN);
861 if (!fkprog->filter) {
862 kfree(fp->orig_prog);
863 return -ENOMEM;
864 }
865
866 return 0;
867 }
868
869 static void bpf_release_orig_filter(struct bpf_prog *fp)
870 {
871 struct sock_fprog_kern *fprog = fp->orig_prog;
872
873 if (fprog) {
874 kfree(fprog->filter);
875 kfree(fprog);
876 }
877 }
878
879 static void __bpf_prog_release(struct bpf_prog *prog)
880 {
881 if (prog->type == BPF_PROG_TYPE_SOCKET_FILTER) {
882 bpf_prog_put(prog);
883 } else {
884 bpf_release_orig_filter(prog);
885 bpf_prog_free(prog);
886 }
887 }
888
889 static void __sk_filter_release(struct sk_filter *fp)
890 {
891 __bpf_prog_release(fp->prog);
892 kfree(fp);
893 }
894
895 /**
896 * sk_filter_release_rcu - Release a socket filter by rcu_head
897 * @rcu: rcu_head that contains the sk_filter to free
898 */
899 static void sk_filter_release_rcu(struct rcu_head *rcu)
900 {
901 struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu);
902
903 __sk_filter_release(fp);
904 }
905
906 /**
907 * sk_filter_release - release a socket filter
908 * @fp: filter to remove
909 *
910 * Remove a filter from a socket and release its resources.
911 */
912 static void sk_filter_release(struct sk_filter *fp)
913 {
914 if (atomic_dec_and_test(&fp->refcnt))
915 call_rcu(&fp->rcu, sk_filter_release_rcu);
916 }
917
918 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
919 {
920 u32 filter_size = bpf_prog_size(fp->prog->len);
921
922 atomic_sub(filter_size, &sk->sk_omem_alloc);
923 sk_filter_release(fp);
924 }
925
926 /* try to charge the socket memory if there is space available
927 * return true on success
928 */
929 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp)
930 {
931 u32 filter_size = bpf_prog_size(fp->prog->len);
932
933 /* same check as in sock_kmalloc() */
934 if (filter_size <= sysctl_optmem_max &&
935 atomic_read(&sk->sk_omem_alloc) + filter_size < sysctl_optmem_max) {
936 atomic_inc(&fp->refcnt);
937 atomic_add(filter_size, &sk->sk_omem_alloc);
938 return true;
939 }
940 return false;
941 }
942
943 static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp)
944 {
945 struct sock_filter *old_prog;
946 struct bpf_prog *old_fp;
947 int err, new_len, old_len = fp->len;
948
949 /* We are free to overwrite insns et al right here as it
950 * won't be used at this point in time anymore internally
951 * after the migration to the internal BPF instruction
952 * representation.
953 */
954 BUILD_BUG_ON(sizeof(struct sock_filter) !=
955 sizeof(struct bpf_insn));
956
957 /* Conversion cannot happen on overlapping memory areas,
958 * so we need to keep the user BPF around until the 2nd
959 * pass. At this time, the user BPF is stored in fp->insns.
960 */
961 old_prog = kmemdup(fp->insns, old_len * sizeof(struct sock_filter),
962 GFP_KERNEL | __GFP_NOWARN);
963 if (!old_prog) {
964 err = -ENOMEM;
965 goto out_err;
966 }
967
968 /* 1st pass: calculate the new program length. */
969 err = bpf_convert_filter(old_prog, old_len, NULL, &new_len);
970 if (err)
971 goto out_err_free;
972
973 /* Expand fp for appending the new filter representation. */
974 old_fp = fp;
975 fp = bpf_prog_realloc(old_fp, bpf_prog_size(new_len), 0);
976 if (!fp) {
977 /* The old_fp is still around in case we couldn't
978 * allocate new memory, so uncharge on that one.
979 */
980 fp = old_fp;
981 err = -ENOMEM;
982 goto out_err_free;
983 }
984
985 fp->len = new_len;
986
987 /* 2nd pass: remap sock_filter insns into bpf_insn insns. */
988 err = bpf_convert_filter(old_prog, old_len, fp->insnsi, &new_len);
989 if (err)
990 /* 2nd bpf_convert_filter() can fail only if it fails
991 * to allocate memory, remapping must succeed. Note,
992 * that at this time old_fp has already been released
993 * by krealloc().
994 */
995 goto out_err_free;
996
997 bpf_prog_select_runtime(fp);
998
999 kfree(old_prog);
1000 return fp;
1001
1002 out_err_free:
1003 kfree(old_prog);
1004 out_err:
1005 __bpf_prog_release(fp);
1006 return ERR_PTR(err);
1007 }
1008
1009 static struct bpf_prog *bpf_prepare_filter(struct bpf_prog *fp,
1010 bpf_aux_classic_check_t trans)
1011 {
1012 int err;
1013
1014 fp->bpf_func = NULL;
1015 fp->jited = 0;
1016
1017 err = bpf_check_classic(fp->insns, fp->len);
1018 if (err) {
1019 __bpf_prog_release(fp);
1020 return ERR_PTR(err);
1021 }
1022
1023 /* There might be additional checks and transformations
1024 * needed on classic filters, f.e. in case of seccomp.
1025 */
1026 if (trans) {
1027 err = trans(fp->insns, fp->len);
1028 if (err) {
1029 __bpf_prog_release(fp);
1030 return ERR_PTR(err);
1031 }
1032 }
1033
1034 /* Probe if we can JIT compile the filter and if so, do
1035 * the compilation of the filter.
1036 */
1037 bpf_jit_compile(fp);
1038
1039 /* JIT compiler couldn't process this filter, so do the
1040 * internal BPF translation for the optimized interpreter.
1041 */
1042 if (!fp->jited)
1043 fp = bpf_migrate_filter(fp);
1044
1045 return fp;
1046 }
1047
1048 /**
1049 * bpf_prog_create - create an unattached filter
1050 * @pfp: the unattached filter that is created
1051 * @fprog: the filter program
1052 *
1053 * Create a filter independent of any socket. We first run some
1054 * sanity checks on it to make sure it does not explode on us later.
1055 * If an error occurs or there is insufficient memory for the filter
1056 * a negative errno code is returned. On success the return is zero.
1057 */
1058 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog)
1059 {
1060 unsigned int fsize = bpf_classic_proglen(fprog);
1061 struct bpf_prog *fp;
1062
1063 /* Make sure new filter is there and in the right amounts. */
1064 if (fprog->filter == NULL)
1065 return -EINVAL;
1066
1067 fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0);
1068 if (!fp)
1069 return -ENOMEM;
1070
1071 memcpy(fp->insns, fprog->filter, fsize);
1072
1073 fp->len = fprog->len;
1074 /* Since unattached filters are not copied back to user
1075 * space through sk_get_filter(), we do not need to hold
1076 * a copy here, and can spare us the work.
1077 */
1078 fp->orig_prog = NULL;
1079
1080 /* bpf_prepare_filter() already takes care of freeing
1081 * memory in case something goes wrong.
1082 */
1083 fp = bpf_prepare_filter(fp, NULL);
1084 if (IS_ERR(fp))
1085 return PTR_ERR(fp);
1086
1087 *pfp = fp;
1088 return 0;
1089 }
1090 EXPORT_SYMBOL_GPL(bpf_prog_create);
1091
1092 /**
1093 * bpf_prog_create_from_user - create an unattached filter from user buffer
1094 * @pfp: the unattached filter that is created
1095 * @fprog: the filter program
1096 * @trans: post-classic verifier transformation handler
1097 * @save_orig: save classic BPF program
1098 *
1099 * This function effectively does the same as bpf_prog_create(), only
1100 * that it builds up its insns buffer from user space provided buffer.
1101 * It also allows for passing a bpf_aux_classic_check_t handler.
1102 */
1103 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
1104 bpf_aux_classic_check_t trans, bool save_orig)
1105 {
1106 unsigned int fsize = bpf_classic_proglen(fprog);
1107 struct bpf_prog *fp;
1108 int err;
1109
1110 /* Make sure new filter is there and in the right amounts. */
1111 if (fprog->filter == NULL)
1112 return -EINVAL;
1113
1114 fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0);
1115 if (!fp)
1116 return -ENOMEM;
1117
1118 if (copy_from_user(fp->insns, fprog->filter, fsize)) {
1119 __bpf_prog_free(fp);
1120 return -EFAULT;
1121 }
1122
1123 fp->len = fprog->len;
1124 fp->orig_prog = NULL;
1125
1126 if (save_orig) {
1127 err = bpf_prog_store_orig_filter(fp, fprog);
1128 if (err) {
1129 __bpf_prog_free(fp);
1130 return -ENOMEM;
1131 }
1132 }
1133
1134 /* bpf_prepare_filter() already takes care of freeing
1135 * memory in case something goes wrong.
1136 */
1137 fp = bpf_prepare_filter(fp, trans);
1138 if (IS_ERR(fp))
1139 return PTR_ERR(fp);
1140
1141 *pfp = fp;
1142 return 0;
1143 }
1144 EXPORT_SYMBOL_GPL(bpf_prog_create_from_user);
1145
1146 void bpf_prog_destroy(struct bpf_prog *fp)
1147 {
1148 __bpf_prog_release(fp);
1149 }
1150 EXPORT_SYMBOL_GPL(bpf_prog_destroy);
1151
1152 static int __sk_attach_prog(struct bpf_prog *prog, struct sock *sk,
1153 bool locked)
1154 {
1155 struct sk_filter *fp, *old_fp;
1156
1157 fp = kmalloc(sizeof(*fp), GFP_KERNEL);
1158 if (!fp)
1159 return -ENOMEM;
1160
1161 fp->prog = prog;
1162 atomic_set(&fp->refcnt, 0);
1163
1164 if (!sk_filter_charge(sk, fp)) {
1165 kfree(fp);
1166 return -ENOMEM;
1167 }
1168
1169 old_fp = rcu_dereference_protected(sk->sk_filter, locked);
1170 rcu_assign_pointer(sk->sk_filter, fp);
1171 if (old_fp)
1172 sk_filter_uncharge(sk, old_fp);
1173
1174 return 0;
1175 }
1176
1177 static int __reuseport_attach_prog(struct bpf_prog *prog, struct sock *sk)
1178 {
1179 struct bpf_prog *old_prog;
1180 int err;
1181
1182 if (bpf_prog_size(prog->len) > sysctl_optmem_max)
1183 return -ENOMEM;
1184
1185 if (sk_unhashed(sk) && sk->sk_reuseport) {
1186 err = reuseport_alloc(sk);
1187 if (err)
1188 return err;
1189 } else if (!rcu_access_pointer(sk->sk_reuseport_cb)) {
1190 /* The socket wasn't bound with SO_REUSEPORT */
1191 return -EINVAL;
1192 }
1193
1194 old_prog = reuseport_attach_prog(sk, prog);
1195 if (old_prog)
1196 bpf_prog_destroy(old_prog);
1197
1198 return 0;
1199 }
1200
1201 static
1202 struct bpf_prog *__get_filter(struct sock_fprog *fprog, struct sock *sk)
1203 {
1204 unsigned int fsize = bpf_classic_proglen(fprog);
1205 unsigned int bpf_fsize = bpf_prog_size(fprog->len);
1206 struct bpf_prog *prog;
1207 int err;
1208
1209 if (sock_flag(sk, SOCK_FILTER_LOCKED))
1210 return ERR_PTR(-EPERM);
1211
1212 /* Make sure new filter is there and in the right amounts. */
1213 if (fprog->filter == NULL)
1214 return ERR_PTR(-EINVAL);
1215
1216 prog = bpf_prog_alloc(bpf_fsize, 0);
1217 if (!prog)
1218 return ERR_PTR(-ENOMEM);
1219
1220 if (copy_from_user(prog->insns, fprog->filter, fsize)) {
1221 __bpf_prog_free(prog);
1222 return ERR_PTR(-EFAULT);
1223 }
1224
1225 prog->len = fprog->len;
1226
1227 err = bpf_prog_store_orig_filter(prog, fprog);
1228 if (err) {
1229 __bpf_prog_free(prog);
1230 return ERR_PTR(-ENOMEM);
1231 }
1232
1233 /* bpf_prepare_filter() already takes care of freeing
1234 * memory in case something goes wrong.
1235 */
1236 return bpf_prepare_filter(prog, NULL);
1237 }
1238
1239 /**
1240 * sk_attach_filter - attach a socket filter
1241 * @fprog: the filter program
1242 * @sk: the socket to use
1243 *
1244 * Attach the user's filter code. We first run some sanity checks on
1245 * it to make sure it does not explode on us later. If an error
1246 * occurs or there is insufficient memory for the filter a negative
1247 * errno code is returned. On success the return is zero.
1248 */
1249 int __sk_attach_filter(struct sock_fprog *fprog, struct sock *sk,
1250 bool locked)
1251 {
1252 struct bpf_prog *prog = __get_filter(fprog, sk);
1253 int err;
1254
1255 if (IS_ERR(prog))
1256 return PTR_ERR(prog);
1257
1258 err = __sk_attach_prog(prog, sk, locked);
1259 if (err < 0) {
1260 __bpf_prog_release(prog);
1261 return err;
1262 }
1263
1264 return 0;
1265 }
1266 EXPORT_SYMBOL_GPL(__sk_attach_filter);
1267
1268 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
1269 {
1270 return __sk_attach_filter(fprog, sk, sock_owned_by_user(sk));
1271 }
1272
1273 int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk)
1274 {
1275 struct bpf_prog *prog = __get_filter(fprog, sk);
1276 int err;
1277
1278 if (IS_ERR(prog))
1279 return PTR_ERR(prog);
1280
1281 err = __reuseport_attach_prog(prog, sk);
1282 if (err < 0) {
1283 __bpf_prog_release(prog);
1284 return err;
1285 }
1286
1287 return 0;
1288 }
1289
1290 static struct bpf_prog *__get_bpf(u32 ufd, struct sock *sk)
1291 {
1292 struct bpf_prog *prog;
1293
1294 if (sock_flag(sk, SOCK_FILTER_LOCKED))
1295 return ERR_PTR(-EPERM);
1296
1297 prog = bpf_prog_get(ufd);
1298 if (IS_ERR(prog))
1299 return prog;
1300
1301 if (prog->type != BPF_PROG_TYPE_SOCKET_FILTER) {
1302 bpf_prog_put(prog);
1303 return ERR_PTR(-EINVAL);
1304 }
1305
1306 return prog;
1307 }
1308
1309 int sk_attach_bpf(u32 ufd, struct sock *sk)
1310 {
1311 struct bpf_prog *prog = __get_bpf(ufd, sk);
1312 int err;
1313
1314 if (IS_ERR(prog))
1315 return PTR_ERR(prog);
1316
1317 err = __sk_attach_prog(prog, sk, sock_owned_by_user(sk));
1318 if (err < 0) {
1319 bpf_prog_put(prog);
1320 return err;
1321 }
1322
1323 return 0;
1324 }
1325
1326 int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk)
1327 {
1328 struct bpf_prog *prog = __get_bpf(ufd, sk);
1329 int err;
1330
1331 if (IS_ERR(prog))
1332 return PTR_ERR(prog);
1333
1334 err = __reuseport_attach_prog(prog, sk);
1335 if (err < 0) {
1336 bpf_prog_put(prog);
1337 return err;
1338 }
1339
1340 return 0;
1341 }
1342
1343 struct bpf_scratchpad {
1344 union {
1345 __be32 diff[MAX_BPF_STACK / sizeof(__be32)];
1346 u8 buff[MAX_BPF_STACK];
1347 };
1348 };
1349
1350 static DEFINE_PER_CPU(struct bpf_scratchpad, bpf_sp);
1351
1352 static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags)
1353 {
1354 struct bpf_scratchpad *sp = this_cpu_ptr(&bpf_sp);
1355 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1356 int offset = (int) r2;
1357 void *from = (void *) (long) r3;
1358 unsigned int len = (unsigned int) r4;
1359 void *ptr;
1360
1361 if (unlikely(flags & ~(BPF_F_RECOMPUTE_CSUM | BPF_F_INVALIDATE_HASH)))
1362 return -EINVAL;
1363
1364 /* bpf verifier guarantees that:
1365 * 'from' pointer points to bpf program stack
1366 * 'len' bytes of it were initialized
1367 * 'len' > 0
1368 * 'skb' is a valid pointer to 'struct sk_buff'
1369 *
1370 * so check for invalid 'offset' and too large 'len'
1371 */
1372 if (unlikely((u32) offset > 0xffff || len > sizeof(sp->buff)))
1373 return -EFAULT;
1374 if (unlikely(skb_try_make_writable(skb, offset + len)))
1375 return -EFAULT;
1376
1377 ptr = skb_header_pointer(skb, offset, len, sp->buff);
1378 if (unlikely(!ptr))
1379 return -EFAULT;
1380
1381 if (flags & BPF_F_RECOMPUTE_CSUM)
1382 skb_postpull_rcsum(skb, ptr, len);
1383
1384 memcpy(ptr, from, len);
1385
1386 if (ptr == sp->buff)
1387 /* skb_store_bits cannot return -EFAULT here */
1388 skb_store_bits(skb, offset, ptr, len);
1389
1390 if (flags & BPF_F_RECOMPUTE_CSUM)
1391 skb_postpush_rcsum(skb, ptr, len);
1392 if (flags & BPF_F_INVALIDATE_HASH)
1393 skb_clear_hash(skb);
1394
1395 return 0;
1396 }
1397
1398 static const struct bpf_func_proto bpf_skb_store_bytes_proto = {
1399 .func = bpf_skb_store_bytes,
1400 .gpl_only = false,
1401 .ret_type = RET_INTEGER,
1402 .arg1_type = ARG_PTR_TO_CTX,
1403 .arg2_type = ARG_ANYTHING,
1404 .arg3_type = ARG_PTR_TO_STACK,
1405 .arg4_type = ARG_CONST_STACK_SIZE,
1406 .arg5_type = ARG_ANYTHING,
1407 };
1408
1409 static u64 bpf_skb_load_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1410 {
1411 const struct sk_buff *skb = (const struct sk_buff *)(unsigned long) r1;
1412 int offset = (int) r2;
1413 void *to = (void *)(unsigned long) r3;
1414 unsigned int len = (unsigned int) r4;
1415 void *ptr;
1416
1417 if (unlikely((u32) offset > 0xffff || len > MAX_BPF_STACK))
1418 return -EFAULT;
1419
1420 ptr = skb_header_pointer(skb, offset, len, to);
1421 if (unlikely(!ptr))
1422 return -EFAULT;
1423 if (ptr != to)
1424 memcpy(to, ptr, len);
1425
1426 return 0;
1427 }
1428
1429 static const struct bpf_func_proto bpf_skb_load_bytes_proto = {
1430 .func = bpf_skb_load_bytes,
1431 .gpl_only = false,
1432 .ret_type = RET_INTEGER,
1433 .arg1_type = ARG_PTR_TO_CTX,
1434 .arg2_type = ARG_ANYTHING,
1435 .arg3_type = ARG_PTR_TO_STACK,
1436 .arg4_type = ARG_CONST_STACK_SIZE,
1437 };
1438
1439 static u64 bpf_l3_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags)
1440 {
1441 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1442 int offset = (int) r2;
1443 __sum16 sum, *ptr;
1444
1445 if (unlikely(flags & ~(BPF_F_HDR_FIELD_MASK)))
1446 return -EINVAL;
1447 if (unlikely((u32) offset > 0xffff))
1448 return -EFAULT;
1449 if (unlikely(skb_try_make_writable(skb, offset + sizeof(sum))))
1450 return -EFAULT;
1451
1452 ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum);
1453 if (unlikely(!ptr))
1454 return -EFAULT;
1455
1456 switch (flags & BPF_F_HDR_FIELD_MASK) {
1457 case 0:
1458 if (unlikely(from != 0))
1459 return -EINVAL;
1460
1461 csum_replace_by_diff(ptr, to);
1462 break;
1463 case 2:
1464 csum_replace2(ptr, from, to);
1465 break;
1466 case 4:
1467 csum_replace4(ptr, from, to);
1468 break;
1469 default:
1470 return -EINVAL;
1471 }
1472
1473 if (ptr == &sum)
1474 /* skb_store_bits guaranteed to not return -EFAULT here */
1475 skb_store_bits(skb, offset, ptr, sizeof(sum));
1476
1477 return 0;
1478 }
1479
1480 static const struct bpf_func_proto bpf_l3_csum_replace_proto = {
1481 .func = bpf_l3_csum_replace,
1482 .gpl_only = false,
1483 .ret_type = RET_INTEGER,
1484 .arg1_type = ARG_PTR_TO_CTX,
1485 .arg2_type = ARG_ANYTHING,
1486 .arg3_type = ARG_ANYTHING,
1487 .arg4_type = ARG_ANYTHING,
1488 .arg5_type = ARG_ANYTHING,
1489 };
1490
1491 static u64 bpf_l4_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags)
1492 {
1493 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1494 bool is_pseudo = flags & BPF_F_PSEUDO_HDR;
1495 bool is_mmzero = flags & BPF_F_MARK_MANGLED_0;
1496 int offset = (int) r2;
1497 __sum16 sum, *ptr;
1498
1499 if (unlikely(flags & ~(BPF_F_MARK_MANGLED_0 | BPF_F_PSEUDO_HDR |
1500 BPF_F_HDR_FIELD_MASK)))
1501 return -EINVAL;
1502 if (unlikely((u32) offset > 0xffff))
1503 return -EFAULT;
1504 if (unlikely(skb_try_make_writable(skb, offset + sizeof(sum))))
1505 return -EFAULT;
1506
1507 ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum);
1508 if (unlikely(!ptr))
1509 return -EFAULT;
1510 if (is_mmzero && !*ptr)
1511 return 0;
1512
1513 switch (flags & BPF_F_HDR_FIELD_MASK) {
1514 case 0:
1515 if (unlikely(from != 0))
1516 return -EINVAL;
1517
1518 inet_proto_csum_replace_by_diff(ptr, skb, to, is_pseudo);
1519 break;
1520 case 2:
1521 inet_proto_csum_replace2(ptr, skb, from, to, is_pseudo);
1522 break;
1523 case 4:
1524 inet_proto_csum_replace4(ptr, skb, from, to, is_pseudo);
1525 break;
1526 default:
1527 return -EINVAL;
1528 }
1529
1530 if (is_mmzero && !*ptr)
1531 *ptr = CSUM_MANGLED_0;
1532 if (ptr == &sum)
1533 /* skb_store_bits guaranteed to not return -EFAULT here */
1534 skb_store_bits(skb, offset, ptr, sizeof(sum));
1535
1536 return 0;
1537 }
1538
1539 static const struct bpf_func_proto bpf_l4_csum_replace_proto = {
1540 .func = bpf_l4_csum_replace,
1541 .gpl_only = false,
1542 .ret_type = RET_INTEGER,
1543 .arg1_type = ARG_PTR_TO_CTX,
1544 .arg2_type = ARG_ANYTHING,
1545 .arg3_type = ARG_ANYTHING,
1546 .arg4_type = ARG_ANYTHING,
1547 .arg5_type = ARG_ANYTHING,
1548 };
1549
1550 static u64 bpf_csum_diff(u64 r1, u64 from_size, u64 r3, u64 to_size, u64 seed)
1551 {
1552 struct bpf_scratchpad *sp = this_cpu_ptr(&bpf_sp);
1553 u64 diff_size = from_size + to_size;
1554 __be32 *from = (__be32 *) (long) r1;
1555 __be32 *to = (__be32 *) (long) r3;
1556 int i, j = 0;
1557
1558 /* This is quite flexible, some examples:
1559 *
1560 * from_size == 0, to_size > 0, seed := csum --> pushing data
1561 * from_size > 0, to_size == 0, seed := csum --> pulling data
1562 * from_size > 0, to_size > 0, seed := 0 --> diffing data
1563 *
1564 * Even for diffing, from_size and to_size don't need to be equal.
1565 */
1566 if (unlikely(((from_size | to_size) & (sizeof(__be32) - 1)) ||
1567 diff_size > sizeof(sp->diff)))
1568 return -EINVAL;
1569
1570 for (i = 0; i < from_size / sizeof(__be32); i++, j++)
1571 sp->diff[j] = ~from[i];
1572 for (i = 0; i < to_size / sizeof(__be32); i++, j++)
1573 sp->diff[j] = to[i];
1574
1575 return csum_partial(sp->diff, diff_size, seed);
1576 }
1577
1578 static const struct bpf_func_proto bpf_csum_diff_proto = {
1579 .func = bpf_csum_diff,
1580 .gpl_only = false,
1581 .ret_type = RET_INTEGER,
1582 .arg1_type = ARG_PTR_TO_STACK,
1583 .arg2_type = ARG_CONST_STACK_SIZE_OR_ZERO,
1584 .arg3_type = ARG_PTR_TO_STACK,
1585 .arg4_type = ARG_CONST_STACK_SIZE_OR_ZERO,
1586 .arg5_type = ARG_ANYTHING,
1587 };
1588
1589 static u64 bpf_clone_redirect(u64 r1, u64 ifindex, u64 flags, u64 r4, u64 r5)
1590 {
1591 struct sk_buff *skb = (struct sk_buff *) (long) r1, *skb2;
1592 struct net_device *dev;
1593
1594 if (unlikely(flags & ~(BPF_F_INGRESS)))
1595 return -EINVAL;
1596
1597 dev = dev_get_by_index_rcu(dev_net(skb->dev), ifindex);
1598 if (unlikely(!dev))
1599 return -EINVAL;
1600
1601 skb2 = skb_clone(skb, GFP_ATOMIC);
1602 if (unlikely(!skb2))
1603 return -ENOMEM;
1604
1605 if (flags & BPF_F_INGRESS) {
1606 if (skb_at_tc_ingress(skb2))
1607 skb_postpush_rcsum(skb2, skb_mac_header(skb2),
1608 skb2->mac_len);
1609 return dev_forward_skb(dev, skb2);
1610 }
1611
1612 skb2->dev = dev;
1613 return dev_queue_xmit(skb2);
1614 }
1615
1616 static const struct bpf_func_proto bpf_clone_redirect_proto = {
1617 .func = bpf_clone_redirect,
1618 .gpl_only = false,
1619 .ret_type = RET_INTEGER,
1620 .arg1_type = ARG_PTR_TO_CTX,
1621 .arg2_type = ARG_ANYTHING,
1622 .arg3_type = ARG_ANYTHING,
1623 };
1624
1625 struct redirect_info {
1626 u32 ifindex;
1627 u32 flags;
1628 };
1629
1630 static DEFINE_PER_CPU(struct redirect_info, redirect_info);
1631
1632 static u64 bpf_redirect(u64 ifindex, u64 flags, u64 r3, u64 r4, u64 r5)
1633 {
1634 struct redirect_info *ri = this_cpu_ptr(&redirect_info);
1635
1636 if (unlikely(flags & ~(BPF_F_INGRESS)))
1637 return TC_ACT_SHOT;
1638
1639 ri->ifindex = ifindex;
1640 ri->flags = flags;
1641
1642 return TC_ACT_REDIRECT;
1643 }
1644
1645 int skb_do_redirect(struct sk_buff *skb)
1646 {
1647 struct redirect_info *ri = this_cpu_ptr(&redirect_info);
1648 struct net_device *dev;
1649
1650 dev = dev_get_by_index_rcu(dev_net(skb->dev), ri->ifindex);
1651 ri->ifindex = 0;
1652 if (unlikely(!dev)) {
1653 kfree_skb(skb);
1654 return -EINVAL;
1655 }
1656
1657 if (ri->flags & BPF_F_INGRESS) {
1658 if (skb_at_tc_ingress(skb))
1659 skb_postpush_rcsum(skb, skb_mac_header(skb),
1660 skb->mac_len);
1661 return dev_forward_skb(dev, skb);
1662 }
1663
1664 skb->dev = dev;
1665 return dev_queue_xmit(skb);
1666 }
1667
1668 static const struct bpf_func_proto bpf_redirect_proto = {
1669 .func = bpf_redirect,
1670 .gpl_only = false,
1671 .ret_type = RET_INTEGER,
1672 .arg1_type = ARG_ANYTHING,
1673 .arg2_type = ARG_ANYTHING,
1674 };
1675
1676 static u64 bpf_get_cgroup_classid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1677 {
1678 return task_get_classid((struct sk_buff *) (unsigned long) r1);
1679 }
1680
1681 static const struct bpf_func_proto bpf_get_cgroup_classid_proto = {
1682 .func = bpf_get_cgroup_classid,
1683 .gpl_only = false,
1684 .ret_type = RET_INTEGER,
1685 .arg1_type = ARG_PTR_TO_CTX,
1686 };
1687
1688 static u64 bpf_get_route_realm(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1689 {
1690 return dst_tclassid((struct sk_buff *) (unsigned long) r1);
1691 }
1692
1693 static const struct bpf_func_proto bpf_get_route_realm_proto = {
1694 .func = bpf_get_route_realm,
1695 .gpl_only = false,
1696 .ret_type = RET_INTEGER,
1697 .arg1_type = ARG_PTR_TO_CTX,
1698 };
1699
1700 static u64 bpf_skb_vlan_push(u64 r1, u64 r2, u64 vlan_tci, u64 r4, u64 r5)
1701 {
1702 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1703 __be16 vlan_proto = (__force __be16) r2;
1704
1705 if (unlikely(vlan_proto != htons(ETH_P_8021Q) &&
1706 vlan_proto != htons(ETH_P_8021AD)))
1707 vlan_proto = htons(ETH_P_8021Q);
1708
1709 return skb_vlan_push(skb, vlan_proto, vlan_tci);
1710 }
1711
1712 const struct bpf_func_proto bpf_skb_vlan_push_proto = {
1713 .func = bpf_skb_vlan_push,
1714 .gpl_only = false,
1715 .ret_type = RET_INTEGER,
1716 .arg1_type = ARG_PTR_TO_CTX,
1717 .arg2_type = ARG_ANYTHING,
1718 .arg3_type = ARG_ANYTHING,
1719 };
1720 EXPORT_SYMBOL_GPL(bpf_skb_vlan_push_proto);
1721
1722 static u64 bpf_skb_vlan_pop(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1723 {
1724 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1725
1726 return skb_vlan_pop(skb);
1727 }
1728
1729 const struct bpf_func_proto bpf_skb_vlan_pop_proto = {
1730 .func = bpf_skb_vlan_pop,
1731 .gpl_only = false,
1732 .ret_type = RET_INTEGER,
1733 .arg1_type = ARG_PTR_TO_CTX,
1734 };
1735 EXPORT_SYMBOL_GPL(bpf_skb_vlan_pop_proto);
1736
1737 bool bpf_helper_changes_skb_data(void *func)
1738 {
1739 if (func == bpf_skb_vlan_push)
1740 return true;
1741 if (func == bpf_skb_vlan_pop)
1742 return true;
1743 if (func == bpf_skb_store_bytes)
1744 return true;
1745 if (func == bpf_l3_csum_replace)
1746 return true;
1747 if (func == bpf_l4_csum_replace)
1748 return true;
1749
1750 return false;
1751 }
1752
1753 static unsigned short bpf_tunnel_key_af(u64 flags)
1754 {
1755 return flags & BPF_F_TUNINFO_IPV6 ? AF_INET6 : AF_INET;
1756 }
1757
1758 static u64 bpf_skb_get_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5)
1759 {
1760 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1761 struct bpf_tunnel_key *to = (struct bpf_tunnel_key *) (long) r2;
1762 const struct ip_tunnel_info *info = skb_tunnel_info(skb);
1763 u8 compat[sizeof(struct bpf_tunnel_key)];
1764
1765 if (unlikely(!info || (flags & ~(BPF_F_TUNINFO_IPV6))))
1766 return -EINVAL;
1767 if (ip_tunnel_info_af(info) != bpf_tunnel_key_af(flags))
1768 return -EPROTO;
1769 if (unlikely(size != sizeof(struct bpf_tunnel_key))) {
1770 switch (size) {
1771 case offsetof(struct bpf_tunnel_key, tunnel_label):
1772 case offsetof(struct bpf_tunnel_key, tunnel_ext):
1773 goto set_compat;
1774 case offsetof(struct bpf_tunnel_key, remote_ipv6[1]):
1775 /* Fixup deprecated structure layouts here, so we have
1776 * a common path later on.
1777 */
1778 if (ip_tunnel_info_af(info) != AF_INET)
1779 return -EINVAL;
1780 set_compat:
1781 to = (struct bpf_tunnel_key *)compat;
1782 break;
1783 default:
1784 return -EINVAL;
1785 }
1786 }
1787
1788 to->tunnel_id = be64_to_cpu(info->key.tun_id);
1789 to->tunnel_tos = info->key.tos;
1790 to->tunnel_ttl = info->key.ttl;
1791
1792 if (flags & BPF_F_TUNINFO_IPV6) {
1793 memcpy(to->remote_ipv6, &info->key.u.ipv6.src,
1794 sizeof(to->remote_ipv6));
1795 to->tunnel_label = be32_to_cpu(info->key.label);
1796 } else {
1797 to->remote_ipv4 = be32_to_cpu(info->key.u.ipv4.src);
1798 }
1799
1800 if (unlikely(size != sizeof(struct bpf_tunnel_key)))
1801 memcpy((void *)(long) r2, to, size);
1802
1803 return 0;
1804 }
1805
1806 static const struct bpf_func_proto bpf_skb_get_tunnel_key_proto = {
1807 .func = bpf_skb_get_tunnel_key,
1808 .gpl_only = false,
1809 .ret_type = RET_INTEGER,
1810 .arg1_type = ARG_PTR_TO_CTX,
1811 .arg2_type = ARG_PTR_TO_STACK,
1812 .arg3_type = ARG_CONST_STACK_SIZE,
1813 .arg4_type = ARG_ANYTHING,
1814 };
1815
1816 static u64 bpf_skb_get_tunnel_opt(u64 r1, u64 r2, u64 size, u64 r4, u64 r5)
1817 {
1818 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1819 u8 *to = (u8 *) (long) r2;
1820 const struct ip_tunnel_info *info = skb_tunnel_info(skb);
1821
1822 if (unlikely(!info ||
1823 !(info->key.tun_flags & TUNNEL_OPTIONS_PRESENT)))
1824 return -ENOENT;
1825 if (unlikely(size < info->options_len))
1826 return -ENOMEM;
1827
1828 ip_tunnel_info_opts_get(to, info);
1829
1830 return info->options_len;
1831 }
1832
1833 static const struct bpf_func_proto bpf_skb_get_tunnel_opt_proto = {
1834 .func = bpf_skb_get_tunnel_opt,
1835 .gpl_only = false,
1836 .ret_type = RET_INTEGER,
1837 .arg1_type = ARG_PTR_TO_CTX,
1838 .arg2_type = ARG_PTR_TO_STACK,
1839 .arg3_type = ARG_CONST_STACK_SIZE,
1840 };
1841
1842 static struct metadata_dst __percpu *md_dst;
1843
1844 static u64 bpf_skb_set_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5)
1845 {
1846 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1847 struct bpf_tunnel_key *from = (struct bpf_tunnel_key *) (long) r2;
1848 struct metadata_dst *md = this_cpu_ptr(md_dst);
1849 u8 compat[sizeof(struct bpf_tunnel_key)];
1850 struct ip_tunnel_info *info;
1851
1852 if (unlikely(flags & ~(BPF_F_TUNINFO_IPV6 | BPF_F_ZERO_CSUM_TX |
1853 BPF_F_DONT_FRAGMENT)))
1854 return -EINVAL;
1855 if (unlikely(size != sizeof(struct bpf_tunnel_key))) {
1856 switch (size) {
1857 case offsetof(struct bpf_tunnel_key, tunnel_label):
1858 case offsetof(struct bpf_tunnel_key, tunnel_ext):
1859 case offsetof(struct bpf_tunnel_key, remote_ipv6[1]):
1860 /* Fixup deprecated structure layouts here, so we have
1861 * a common path later on.
1862 */
1863 memcpy(compat, from, size);
1864 memset(compat + size, 0, sizeof(compat) - size);
1865 from = (struct bpf_tunnel_key *)compat;
1866 break;
1867 default:
1868 return -EINVAL;
1869 }
1870 }
1871 if (unlikely((!(flags & BPF_F_TUNINFO_IPV6) && from->tunnel_label) ||
1872 from->tunnel_ext))
1873 return -EINVAL;
1874
1875 skb_dst_drop(skb);
1876 dst_hold((struct dst_entry *) md);
1877 skb_dst_set(skb, (struct dst_entry *) md);
1878
1879 info = &md->u.tun_info;
1880 info->mode = IP_TUNNEL_INFO_TX;
1881
1882 info->key.tun_flags = TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_NOCACHE;
1883 if (flags & BPF_F_DONT_FRAGMENT)
1884 info->key.tun_flags |= TUNNEL_DONT_FRAGMENT;
1885
1886 info->key.tun_id = cpu_to_be64(from->tunnel_id);
1887 info->key.tos = from->tunnel_tos;
1888 info->key.ttl = from->tunnel_ttl;
1889
1890 if (flags & BPF_F_TUNINFO_IPV6) {
1891 info->mode |= IP_TUNNEL_INFO_IPV6;
1892 memcpy(&info->key.u.ipv6.dst, from->remote_ipv6,
1893 sizeof(from->remote_ipv6));
1894 info->key.label = cpu_to_be32(from->tunnel_label) &
1895 IPV6_FLOWLABEL_MASK;
1896 } else {
1897 info->key.u.ipv4.dst = cpu_to_be32(from->remote_ipv4);
1898 if (flags & BPF_F_ZERO_CSUM_TX)
1899 info->key.tun_flags &= ~TUNNEL_CSUM;
1900 }
1901
1902 return 0;
1903 }
1904
1905 static const struct bpf_func_proto bpf_skb_set_tunnel_key_proto = {
1906 .func = bpf_skb_set_tunnel_key,
1907 .gpl_only = false,
1908 .ret_type = RET_INTEGER,
1909 .arg1_type = ARG_PTR_TO_CTX,
1910 .arg2_type = ARG_PTR_TO_STACK,
1911 .arg3_type = ARG_CONST_STACK_SIZE,
1912 .arg4_type = ARG_ANYTHING,
1913 };
1914
1915 static u64 bpf_skb_set_tunnel_opt(u64 r1, u64 r2, u64 size, u64 r4, u64 r5)
1916 {
1917 struct sk_buff *skb = (struct sk_buff *) (long) r1;
1918 u8 *from = (u8 *) (long) r2;
1919 struct ip_tunnel_info *info = skb_tunnel_info(skb);
1920 const struct metadata_dst *md = this_cpu_ptr(md_dst);
1921
1922 if (unlikely(info != &md->u.tun_info || (size & (sizeof(u32) - 1))))
1923 return -EINVAL;
1924 if (unlikely(size > IP_TUNNEL_OPTS_MAX))
1925 return -ENOMEM;
1926
1927 ip_tunnel_info_opts_set(info, from, size);
1928
1929 return 0;
1930 }
1931
1932 static const struct bpf_func_proto bpf_skb_set_tunnel_opt_proto = {
1933 .func = bpf_skb_set_tunnel_opt,
1934 .gpl_only = false,
1935 .ret_type = RET_INTEGER,
1936 .arg1_type = ARG_PTR_TO_CTX,
1937 .arg2_type = ARG_PTR_TO_STACK,
1938 .arg3_type = ARG_CONST_STACK_SIZE,
1939 };
1940
1941 static const struct bpf_func_proto *
1942 bpf_get_skb_set_tunnel_proto(enum bpf_func_id which)
1943 {
1944 if (!md_dst) {
1945 /* Race is not possible, since it's called from verifier
1946 * that is holding verifier mutex.
1947 */
1948 md_dst = metadata_dst_alloc_percpu(IP_TUNNEL_OPTS_MAX,
1949 GFP_KERNEL);
1950 if (!md_dst)
1951 return NULL;
1952 }
1953
1954 switch (which) {
1955 case BPF_FUNC_skb_set_tunnel_key:
1956 return &bpf_skb_set_tunnel_key_proto;
1957 case BPF_FUNC_skb_set_tunnel_opt:
1958 return &bpf_skb_set_tunnel_opt_proto;
1959 default:
1960 return NULL;
1961 }
1962 }
1963
1964 static const struct bpf_func_proto *
1965 sk_filter_func_proto(enum bpf_func_id func_id)
1966 {
1967 switch (func_id) {
1968 case BPF_FUNC_map_lookup_elem:
1969 return &bpf_map_lookup_elem_proto;
1970 case BPF_FUNC_map_update_elem:
1971 return &bpf_map_update_elem_proto;
1972 case BPF_FUNC_map_delete_elem:
1973 return &bpf_map_delete_elem_proto;
1974 case BPF_FUNC_get_prandom_u32:
1975 return &bpf_get_prandom_u32_proto;
1976 case BPF_FUNC_get_smp_processor_id:
1977 return &bpf_get_smp_processor_id_proto;
1978 case BPF_FUNC_tail_call:
1979 return &bpf_tail_call_proto;
1980 case BPF_FUNC_ktime_get_ns:
1981 return &bpf_ktime_get_ns_proto;
1982 case BPF_FUNC_trace_printk:
1983 if (capable(CAP_SYS_ADMIN))
1984 return bpf_get_trace_printk_proto();
1985 default:
1986 return NULL;
1987 }
1988 }
1989
1990 static const struct bpf_func_proto *
1991 tc_cls_act_func_proto(enum bpf_func_id func_id)
1992 {
1993 switch (func_id) {
1994 case BPF_FUNC_skb_store_bytes:
1995 return &bpf_skb_store_bytes_proto;
1996 case BPF_FUNC_skb_load_bytes:
1997 return &bpf_skb_load_bytes_proto;
1998 case BPF_FUNC_csum_diff:
1999 return &bpf_csum_diff_proto;
2000 case BPF_FUNC_l3_csum_replace:
2001 return &bpf_l3_csum_replace_proto;
2002 case BPF_FUNC_l4_csum_replace:
2003 return &bpf_l4_csum_replace_proto;
2004 case BPF_FUNC_clone_redirect:
2005 return &bpf_clone_redirect_proto;
2006 case BPF_FUNC_get_cgroup_classid:
2007 return &bpf_get_cgroup_classid_proto;
2008 case BPF_FUNC_skb_vlan_push:
2009 return &bpf_skb_vlan_push_proto;
2010 case BPF_FUNC_skb_vlan_pop:
2011 return &bpf_skb_vlan_pop_proto;
2012 case BPF_FUNC_skb_get_tunnel_key:
2013 return &bpf_skb_get_tunnel_key_proto;
2014 case BPF_FUNC_skb_set_tunnel_key:
2015 return bpf_get_skb_set_tunnel_proto(func_id);
2016 case BPF_FUNC_skb_get_tunnel_opt:
2017 return &bpf_skb_get_tunnel_opt_proto;
2018 case BPF_FUNC_skb_set_tunnel_opt:
2019 return bpf_get_skb_set_tunnel_proto(func_id);
2020 case BPF_FUNC_redirect:
2021 return &bpf_redirect_proto;
2022 case BPF_FUNC_get_route_realm:
2023 return &bpf_get_route_realm_proto;
2024 default:
2025 return sk_filter_func_proto(func_id);
2026 }
2027 }
2028
2029 static bool __is_valid_access(int off, int size, enum bpf_access_type type)
2030 {
2031 /* check bounds */
2032 if (off < 0 || off >= sizeof(struct __sk_buff))
2033 return false;
2034
2035 /* disallow misaligned access */
2036 if (off % size != 0)
2037 return false;
2038
2039 /* all __sk_buff fields are __u32 */
2040 if (size != 4)
2041 return false;
2042
2043 return true;
2044 }
2045
2046 static bool sk_filter_is_valid_access(int off, int size,
2047 enum bpf_access_type type)
2048 {
2049 if (off == offsetof(struct __sk_buff, tc_classid))
2050 return false;
2051
2052 if (type == BPF_WRITE) {
2053 switch (off) {
2054 case offsetof(struct __sk_buff, cb[0]) ...
2055 offsetof(struct __sk_buff, cb[4]):
2056 break;
2057 default:
2058 return false;
2059 }
2060 }
2061
2062 return __is_valid_access(off, size, type);
2063 }
2064
2065 static bool tc_cls_act_is_valid_access(int off, int size,
2066 enum bpf_access_type type)
2067 {
2068 if (type == BPF_WRITE) {
2069 switch (off) {
2070 case offsetof(struct __sk_buff, mark):
2071 case offsetof(struct __sk_buff, tc_index):
2072 case offsetof(struct __sk_buff, priority):
2073 case offsetof(struct __sk_buff, cb[0]) ...
2074 offsetof(struct __sk_buff, cb[4]):
2075 case offsetof(struct __sk_buff, tc_classid):
2076 break;
2077 default:
2078 return false;
2079 }
2080 }
2081 return __is_valid_access(off, size, type);
2082 }
2083
2084 static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg,
2085 int src_reg, int ctx_off,
2086 struct bpf_insn *insn_buf,
2087 struct bpf_prog *prog)
2088 {
2089 struct bpf_insn *insn = insn_buf;
2090
2091 switch (ctx_off) {
2092 case offsetof(struct __sk_buff, len):
2093 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
2094
2095 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
2096 offsetof(struct sk_buff, len));
2097 break;
2098
2099 case offsetof(struct __sk_buff, protocol):
2100 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
2101
2102 *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
2103 offsetof(struct sk_buff, protocol));
2104 break;
2105
2106 case offsetof(struct __sk_buff, vlan_proto):
2107 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
2108
2109 *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
2110 offsetof(struct sk_buff, vlan_proto));
2111 break;
2112
2113 case offsetof(struct __sk_buff, priority):
2114 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, priority) != 4);
2115
2116 if (type == BPF_WRITE)
2117 *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg,
2118 offsetof(struct sk_buff, priority));
2119 else
2120 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
2121 offsetof(struct sk_buff, priority));
2122 break;
2123
2124 case offsetof(struct __sk_buff, ingress_ifindex):
2125 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, skb_iif) != 4);
2126
2127 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
2128 offsetof(struct sk_buff, skb_iif));
2129 break;
2130
2131 case offsetof(struct __sk_buff, ifindex):
2132 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
2133
2134 *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)),
2135 dst_reg, src_reg,
2136 offsetof(struct sk_buff, dev));
2137 *insn++ = BPF_JMP_IMM(BPF_JEQ, dst_reg, 0, 1);
2138 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, dst_reg,
2139 offsetof(struct net_device, ifindex));
2140 break;
2141
2142 case offsetof(struct __sk_buff, hash):
2143 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
2144
2145 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
2146 offsetof(struct sk_buff, hash));
2147 break;
2148
2149 case offsetof(struct __sk_buff, mark):
2150 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
2151
2152 if (type == BPF_WRITE)
2153 *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg,
2154 offsetof(struct sk_buff, mark));
2155 else
2156 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
2157 offsetof(struct sk_buff, mark));
2158 break;
2159
2160 case offsetof(struct __sk_buff, pkt_type):
2161 return convert_skb_access(SKF_AD_PKTTYPE, dst_reg, src_reg, insn);
2162
2163 case offsetof(struct __sk_buff, queue_mapping):
2164 return convert_skb_access(SKF_AD_QUEUE, dst_reg, src_reg, insn);
2165
2166 case offsetof(struct __sk_buff, vlan_present):
2167 return convert_skb_access(SKF_AD_VLAN_TAG_PRESENT,
2168 dst_reg, src_reg, insn);
2169
2170 case offsetof(struct __sk_buff, vlan_tci):
2171 return convert_skb_access(SKF_AD_VLAN_TAG,
2172 dst_reg, src_reg, insn);
2173
2174 case offsetof(struct __sk_buff, cb[0]) ...
2175 offsetof(struct __sk_buff, cb[4]):
2176 BUILD_BUG_ON(FIELD_SIZEOF(struct qdisc_skb_cb, data) < 20);
2177
2178 prog->cb_access = 1;
2179 ctx_off -= offsetof(struct __sk_buff, cb[0]);
2180 ctx_off += offsetof(struct sk_buff, cb);
2181 ctx_off += offsetof(struct qdisc_skb_cb, data);
2182 if (type == BPF_WRITE)
2183 *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg, ctx_off);
2184 else
2185 *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, ctx_off);
2186 break;
2187
2188 case offsetof(struct __sk_buff, tc_classid):
2189 ctx_off -= offsetof(struct __sk_buff, tc_classid);
2190 ctx_off += offsetof(struct sk_buff, cb);
2191 ctx_off += offsetof(struct qdisc_skb_cb, tc_classid);
2192 if (type == BPF_WRITE)
2193 *insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg, ctx_off);
2194 else
2195 *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg, ctx_off);
2196 break;
2197
2198 case offsetof(struct __sk_buff, tc_index):
2199 #ifdef CONFIG_NET_SCHED
2200 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, tc_index) != 2);
2201
2202 if (type == BPF_WRITE)
2203 *insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg,
2204 offsetof(struct sk_buff, tc_index));
2205 else
2206 *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
2207 offsetof(struct sk_buff, tc_index));
2208 break;
2209 #else
2210 if (type == BPF_WRITE)
2211 *insn++ = BPF_MOV64_REG(dst_reg, dst_reg);
2212 else
2213 *insn++ = BPF_MOV64_IMM(dst_reg, 0);
2214 break;
2215 #endif
2216 }
2217
2218 return insn - insn_buf;
2219 }
2220
2221 static const struct bpf_verifier_ops sk_filter_ops = {
2222 .get_func_proto = sk_filter_func_proto,
2223 .is_valid_access = sk_filter_is_valid_access,
2224 .convert_ctx_access = bpf_net_convert_ctx_access,
2225 };
2226
2227 static const struct bpf_verifier_ops tc_cls_act_ops = {
2228 .get_func_proto = tc_cls_act_func_proto,
2229 .is_valid_access = tc_cls_act_is_valid_access,
2230 .convert_ctx_access = bpf_net_convert_ctx_access,
2231 };
2232
2233 static struct bpf_prog_type_list sk_filter_type __read_mostly = {
2234 .ops = &sk_filter_ops,
2235 .type = BPF_PROG_TYPE_SOCKET_FILTER,
2236 };
2237
2238 static struct bpf_prog_type_list sched_cls_type __read_mostly = {
2239 .ops = &tc_cls_act_ops,
2240 .type = BPF_PROG_TYPE_SCHED_CLS,
2241 };
2242
2243 static struct bpf_prog_type_list sched_act_type __read_mostly = {
2244 .ops = &tc_cls_act_ops,
2245 .type = BPF_PROG_TYPE_SCHED_ACT,
2246 };
2247
2248 static int __init register_sk_filter_ops(void)
2249 {
2250 bpf_register_prog_type(&sk_filter_type);
2251 bpf_register_prog_type(&sched_cls_type);
2252 bpf_register_prog_type(&sched_act_type);
2253
2254 return 0;
2255 }
2256 late_initcall(register_sk_filter_ops);
2257
2258 int __sk_detach_filter(struct sock *sk, bool locked)
2259 {
2260 int ret = -ENOENT;
2261 struct sk_filter *filter;
2262
2263 if (sock_flag(sk, SOCK_FILTER_LOCKED))
2264 return -EPERM;
2265
2266 filter = rcu_dereference_protected(sk->sk_filter, locked);
2267 if (filter) {
2268 RCU_INIT_POINTER(sk->sk_filter, NULL);
2269 sk_filter_uncharge(sk, filter);
2270 ret = 0;
2271 }
2272
2273 return ret;
2274 }
2275 EXPORT_SYMBOL_GPL(__sk_detach_filter);
2276
2277 int sk_detach_filter(struct sock *sk)
2278 {
2279 return __sk_detach_filter(sk, sock_owned_by_user(sk));
2280 }
2281
2282 int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf,
2283 unsigned int len)
2284 {
2285 struct sock_fprog_kern *fprog;
2286 struct sk_filter *filter;
2287 int ret = 0;
2288
2289 lock_sock(sk);
2290 filter = rcu_dereference_protected(sk->sk_filter,
2291 sock_owned_by_user(sk));
2292 if (!filter)
2293 goto out;
2294
2295 /* We're copying the filter that has been originally attached,
2296 * so no conversion/decode needed anymore. eBPF programs that
2297 * have no original program cannot be dumped through this.
2298 */
2299 ret = -EACCES;
2300 fprog = filter->prog->orig_prog;
2301 if (!fprog)
2302 goto out;
2303
2304 ret = fprog->len;
2305 if (!len)
2306 /* User space only enquires number of filter blocks. */
2307 goto out;
2308
2309 ret = -EINVAL;
2310 if (len < fprog->len)
2311 goto out;
2312
2313 ret = -EFAULT;
2314 if (copy_to_user(ubuf, fprog->filter, bpf_classic_proglen(fprog)))
2315 goto out;
2316
2317 /* Instead of bytes, the API requests to return the number
2318 * of filter blocks.
2319 */
2320 ret = fprog->len;
2321 out:
2322 release_sock(sk);
2323 return ret;
2324 }
Linux kernel - Deliverables
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