Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Linux Socket Filter - Kernel level socket filtering | |
3 | * | |
bd4cf0ed AS |
4 | * Based on the design of the Berkeley Packet Filter. The new |
5 | * internal format has been designed by PLUMgrid: | |
1da177e4 | 6 | * |
bd4cf0ed AS |
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> | |
1da177e4 LT |
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. | |
4df95ff4 | 21 | * Kris Katterjohn - Added many additional checks in bpf_check_classic() |
1da177e4 LT |
22 | */ |
23 | ||
24 | #include <linux/module.h> | |
25 | #include <linux/types.h> | |
1da177e4 LT |
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> | |
5a0e3ad6 | 33 | #include <linux/gfp.h> |
1da177e4 LT |
34 | #include <net/ip.h> |
35 | #include <net/protocol.h> | |
4738c1db | 36 | #include <net/netlink.h> |
1da177e4 LT |
37 | #include <linux/skbuff.h> |
38 | #include <net/sock.h> | |
10b89ee4 | 39 | #include <net/flow_dissector.h> |
1da177e4 LT |
40 | #include <linux/errno.h> |
41 | #include <linux/timer.h> | |
1da177e4 | 42 | #include <asm/uaccess.h> |
40daafc8 | 43 | #include <asm/unaligned.h> |
1da177e4 | 44 | #include <linux/filter.h> |
86e4ca66 | 45 | #include <linux/ratelimit.h> |
46b325c7 | 46 | #include <linux/seccomp.h> |
f3335031 | 47 | #include <linux/if_vlan.h> |
89aa0758 | 48 | #include <linux/bpf.h> |
d691f9e8 | 49 | #include <net/sch_generic.h> |
8d20aabe | 50 | #include <net/cls_cgroup.h> |
1da177e4 | 51 | |
43db6d65 SH |
52 | /** |
53 | * sk_filter - run a packet through a socket filter | |
54 | * @sk: sock associated with &sk_buff | |
55 | * @skb: buffer to filter | |
43db6d65 SH |
56 | * |
57 | * Run the filter code and then cut skb->data to correct size returned by | |
8ea6e345 | 58 | * SK_RUN_FILTER. If pkt_len is 0 we toss packet. If skb->len is smaller |
43db6d65 | 59 | * than pkt_len we keep whole skb->data. This is the socket level |
8ea6e345 | 60 | * wrapper to SK_RUN_FILTER. It returns 0 if the packet should |
43db6d65 SH |
61 | * be accepted or -EPERM if the packet should be tossed. |
62 | * | |
63 | */ | |
64 | int sk_filter(struct sock *sk, struct sk_buff *skb) | |
65 | { | |
66 | int err; | |
67 | struct sk_filter *filter; | |
68 | ||
c93bdd0e MG |
69 | /* |
70 | * If the skb was allocated from pfmemalloc reserves, only | |
71 | * allow SOCK_MEMALLOC sockets to use it as this socket is | |
72 | * helping free memory | |
73 | */ | |
74 | if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC)) | |
75 | return -ENOMEM; | |
76 | ||
43db6d65 SH |
77 | err = security_sock_rcv_skb(sk, skb); |
78 | if (err) | |
79 | return err; | |
80 | ||
80f8f102 ED |
81 | rcu_read_lock(); |
82 | filter = rcu_dereference(sk->sk_filter); | |
43db6d65 | 83 | if (filter) { |
0a14842f | 84 | unsigned int pkt_len = SK_RUN_FILTER(filter, skb); |
0d7da9dd | 85 | |
43db6d65 SH |
86 | err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM; |
87 | } | |
80f8f102 | 88 | rcu_read_unlock(); |
43db6d65 SH |
89 | |
90 | return err; | |
91 | } | |
92 | EXPORT_SYMBOL(sk_filter); | |
93 | ||
30743837 | 94 | static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) |
bd4cf0ed | 95 | { |
56193d1b | 96 | return skb_get_poff((struct sk_buff *)(unsigned long) ctx); |
bd4cf0ed AS |
97 | } |
98 | ||
30743837 | 99 | static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) |
bd4cf0ed | 100 | { |
eb9672f4 | 101 | struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx; |
bd4cf0ed AS |
102 | struct nlattr *nla; |
103 | ||
104 | if (skb_is_nonlinear(skb)) | |
105 | return 0; | |
106 | ||
05ab8f26 MK |
107 | if (skb->len < sizeof(struct nlattr)) |
108 | return 0; | |
109 | ||
30743837 | 110 | if (a > skb->len - sizeof(struct nlattr)) |
bd4cf0ed AS |
111 | return 0; |
112 | ||
30743837 | 113 | nla = nla_find((struct nlattr *) &skb->data[a], skb->len - a, x); |
bd4cf0ed AS |
114 | if (nla) |
115 | return (void *) nla - (void *) skb->data; | |
116 | ||
117 | return 0; | |
118 | } | |
119 | ||
30743837 | 120 | static u64 __skb_get_nlattr_nest(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) |
bd4cf0ed | 121 | { |
eb9672f4 | 122 | struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx; |
bd4cf0ed AS |
123 | struct nlattr *nla; |
124 | ||
125 | if (skb_is_nonlinear(skb)) | |
126 | return 0; | |
127 | ||
05ab8f26 MK |
128 | if (skb->len < sizeof(struct nlattr)) |
129 | return 0; | |
130 | ||
30743837 | 131 | if (a > skb->len - sizeof(struct nlattr)) |
bd4cf0ed AS |
132 | return 0; |
133 | ||
30743837 DB |
134 | nla = (struct nlattr *) &skb->data[a]; |
135 | if (nla->nla_len > skb->len - a) | |
bd4cf0ed AS |
136 | return 0; |
137 | ||
30743837 | 138 | nla = nla_find_nested(nla, x); |
bd4cf0ed AS |
139 | if (nla) |
140 | return (void *) nla - (void *) skb->data; | |
141 | ||
142 | return 0; | |
143 | } | |
144 | ||
30743837 | 145 | static u64 __get_raw_cpu_id(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) |
bd4cf0ed AS |
146 | { |
147 | return raw_smp_processor_id(); | |
148 | } | |
149 | ||
4cd3675e | 150 | /* note that this only generates 32-bit random numbers */ |
30743837 | 151 | static u64 __get_random_u32(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) |
4cd3675e | 152 | { |
eb9672f4 | 153 | return prandom_u32(); |
4cd3675e CG |
154 | } |
155 | ||
9bac3d6d AS |
156 | static u32 convert_skb_access(int skb_field, int dst_reg, int src_reg, |
157 | struct bpf_insn *insn_buf) | |
158 | { | |
159 | struct bpf_insn *insn = insn_buf; | |
160 | ||
161 | switch (skb_field) { | |
162 | case SKF_AD_MARK: | |
163 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); | |
164 | ||
165 | *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, | |
166 | offsetof(struct sk_buff, mark)); | |
167 | break; | |
168 | ||
169 | case SKF_AD_PKTTYPE: | |
170 | *insn++ = BPF_LDX_MEM(BPF_B, dst_reg, src_reg, PKT_TYPE_OFFSET()); | |
171 | *insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, PKT_TYPE_MAX); | |
172 | #ifdef __BIG_ENDIAN_BITFIELD | |
173 | *insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 5); | |
174 | #endif | |
175 | break; | |
176 | ||
177 | case SKF_AD_QUEUE: | |
178 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2); | |
179 | ||
180 | *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg, | |
181 | offsetof(struct sk_buff, queue_mapping)); | |
182 | break; | |
c2497395 | 183 | |
c2497395 AS |
184 | case SKF_AD_VLAN_TAG: |
185 | case SKF_AD_VLAN_TAG_PRESENT: | |
186 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2); | |
187 | BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000); | |
188 | ||
189 | /* dst_reg = *(u16 *) (src_reg + offsetof(vlan_tci)) */ | |
190 | *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg, | |
191 | offsetof(struct sk_buff, vlan_tci)); | |
192 | if (skb_field == SKF_AD_VLAN_TAG) { | |
193 | *insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, | |
194 | ~VLAN_TAG_PRESENT); | |
195 | } else { | |
196 | /* dst_reg >>= 12 */ | |
197 | *insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 12); | |
198 | /* dst_reg &= 1 */ | |
199 | *insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, 1); | |
200 | } | |
201 | break; | |
9bac3d6d AS |
202 | } |
203 | ||
204 | return insn - insn_buf; | |
205 | } | |
206 | ||
bd4cf0ed | 207 | static bool convert_bpf_extensions(struct sock_filter *fp, |
2695fb55 | 208 | struct bpf_insn **insnp) |
bd4cf0ed | 209 | { |
2695fb55 | 210 | struct bpf_insn *insn = *insnp; |
9bac3d6d | 211 | u32 cnt; |
bd4cf0ed AS |
212 | |
213 | switch (fp->k) { | |
214 | case SKF_AD_OFF + SKF_AD_PROTOCOL: | |
0b8c707d DB |
215 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2); |
216 | ||
217 | /* A = *(u16 *) (CTX + offsetof(protocol)) */ | |
218 | *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX, | |
219 | offsetof(struct sk_buff, protocol)); | |
220 | /* A = ntohs(A) [emitting a nop or swap16] */ | |
221 | *insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16); | |
bd4cf0ed AS |
222 | break; |
223 | ||
224 | case SKF_AD_OFF + SKF_AD_PKTTYPE: | |
9bac3d6d AS |
225 | cnt = convert_skb_access(SKF_AD_PKTTYPE, BPF_REG_A, BPF_REG_CTX, insn); |
226 | insn += cnt - 1; | |
bd4cf0ed AS |
227 | break; |
228 | ||
229 | case SKF_AD_OFF + SKF_AD_IFINDEX: | |
230 | case SKF_AD_OFF + SKF_AD_HATYPE: | |
bd4cf0ed AS |
231 | BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); |
232 | BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2); | |
f8f6d679 DB |
233 | BUILD_BUG_ON(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)) < 0); |
234 | ||
235 | *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)), | |
236 | BPF_REG_TMP, BPF_REG_CTX, | |
237 | offsetof(struct sk_buff, dev)); | |
238 | /* if (tmp != 0) goto pc + 1 */ | |
239 | *insn++ = BPF_JMP_IMM(BPF_JNE, BPF_REG_TMP, 0, 1); | |
240 | *insn++ = BPF_EXIT_INSN(); | |
241 | if (fp->k == SKF_AD_OFF + SKF_AD_IFINDEX) | |
242 | *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_TMP, | |
243 | offsetof(struct net_device, ifindex)); | |
244 | else | |
245 | *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_TMP, | |
246 | offsetof(struct net_device, type)); | |
bd4cf0ed AS |
247 | break; |
248 | ||
249 | case SKF_AD_OFF + SKF_AD_MARK: | |
9bac3d6d AS |
250 | cnt = convert_skb_access(SKF_AD_MARK, BPF_REG_A, BPF_REG_CTX, insn); |
251 | insn += cnt - 1; | |
bd4cf0ed AS |
252 | break; |
253 | ||
254 | case SKF_AD_OFF + SKF_AD_RXHASH: | |
255 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4); | |
256 | ||
9739eef1 AS |
257 | *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, |
258 | offsetof(struct sk_buff, hash)); | |
bd4cf0ed AS |
259 | break; |
260 | ||
261 | case SKF_AD_OFF + SKF_AD_QUEUE: | |
9bac3d6d AS |
262 | cnt = convert_skb_access(SKF_AD_QUEUE, BPF_REG_A, BPF_REG_CTX, insn); |
263 | insn += cnt - 1; | |
bd4cf0ed AS |
264 | break; |
265 | ||
266 | case SKF_AD_OFF + SKF_AD_VLAN_TAG: | |
c2497395 AS |
267 | cnt = convert_skb_access(SKF_AD_VLAN_TAG, |
268 | BPF_REG_A, BPF_REG_CTX, insn); | |
269 | insn += cnt - 1; | |
270 | break; | |
bd4cf0ed | 271 | |
c2497395 AS |
272 | case SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT: |
273 | cnt = convert_skb_access(SKF_AD_VLAN_TAG_PRESENT, | |
274 | BPF_REG_A, BPF_REG_CTX, insn); | |
275 | insn += cnt - 1; | |
bd4cf0ed AS |
276 | break; |
277 | ||
27cd5452 MS |
278 | case SKF_AD_OFF + SKF_AD_VLAN_TPID: |
279 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2); | |
280 | ||
281 | /* A = *(u16 *) (CTX + offsetof(vlan_proto)) */ | |
282 | *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX, | |
283 | offsetof(struct sk_buff, vlan_proto)); | |
284 | /* A = ntohs(A) [emitting a nop or swap16] */ | |
285 | *insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16); | |
286 | break; | |
287 | ||
bd4cf0ed AS |
288 | case SKF_AD_OFF + SKF_AD_PAY_OFFSET: |
289 | case SKF_AD_OFF + SKF_AD_NLATTR: | |
290 | case SKF_AD_OFF + SKF_AD_NLATTR_NEST: | |
291 | case SKF_AD_OFF + SKF_AD_CPU: | |
4cd3675e | 292 | case SKF_AD_OFF + SKF_AD_RANDOM: |
e430f34e | 293 | /* arg1 = CTX */ |
f8f6d679 | 294 | *insn++ = BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_CTX); |
bd4cf0ed | 295 | /* arg2 = A */ |
f8f6d679 | 296 | *insn++ = BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_A); |
bd4cf0ed | 297 | /* arg3 = X */ |
f8f6d679 | 298 | *insn++ = BPF_MOV64_REG(BPF_REG_ARG3, BPF_REG_X); |
e430f34e | 299 | /* Emit call(arg1=CTX, arg2=A, arg3=X) */ |
bd4cf0ed AS |
300 | switch (fp->k) { |
301 | case SKF_AD_OFF + SKF_AD_PAY_OFFSET: | |
f8f6d679 | 302 | *insn = BPF_EMIT_CALL(__skb_get_pay_offset); |
bd4cf0ed AS |
303 | break; |
304 | case SKF_AD_OFF + SKF_AD_NLATTR: | |
f8f6d679 | 305 | *insn = BPF_EMIT_CALL(__skb_get_nlattr); |
bd4cf0ed AS |
306 | break; |
307 | case SKF_AD_OFF + SKF_AD_NLATTR_NEST: | |
f8f6d679 | 308 | *insn = BPF_EMIT_CALL(__skb_get_nlattr_nest); |
bd4cf0ed AS |
309 | break; |
310 | case SKF_AD_OFF + SKF_AD_CPU: | |
f8f6d679 | 311 | *insn = BPF_EMIT_CALL(__get_raw_cpu_id); |
bd4cf0ed | 312 | break; |
4cd3675e | 313 | case SKF_AD_OFF + SKF_AD_RANDOM: |
f8f6d679 | 314 | *insn = BPF_EMIT_CALL(__get_random_u32); |
4cd3675e | 315 | break; |
bd4cf0ed AS |
316 | } |
317 | break; | |
318 | ||
319 | case SKF_AD_OFF + SKF_AD_ALU_XOR_X: | |
9739eef1 AS |
320 | /* A ^= X */ |
321 | *insn = BPF_ALU32_REG(BPF_XOR, BPF_REG_A, BPF_REG_X); | |
bd4cf0ed AS |
322 | break; |
323 | ||
324 | default: | |
325 | /* This is just a dummy call to avoid letting the compiler | |
326 | * evict __bpf_call_base() as an optimization. Placed here | |
327 | * where no-one bothers. | |
328 | */ | |
329 | BUG_ON(__bpf_call_base(0, 0, 0, 0, 0) != 0); | |
330 | return false; | |
331 | } | |
332 | ||
333 | *insnp = insn; | |
334 | return true; | |
335 | } | |
336 | ||
337 | /** | |
8fb575ca | 338 | * bpf_convert_filter - convert filter program |
bd4cf0ed AS |
339 | * @prog: the user passed filter program |
340 | * @len: the length of the user passed filter program | |
341 | * @new_prog: buffer where converted program will be stored | |
342 | * @new_len: pointer to store length of converted program | |
343 | * | |
344 | * Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style. | |
345 | * Conversion workflow: | |
346 | * | |
347 | * 1) First pass for calculating the new program length: | |
8fb575ca | 348 | * bpf_convert_filter(old_prog, old_len, NULL, &new_len) |
bd4cf0ed AS |
349 | * |
350 | * 2) 2nd pass to remap in two passes: 1st pass finds new | |
351 | * jump offsets, 2nd pass remapping: | |
2695fb55 | 352 | * new_prog = kmalloc(sizeof(struct bpf_insn) * new_len); |
8fb575ca | 353 | * bpf_convert_filter(old_prog, old_len, new_prog, &new_len); |
bd4cf0ed AS |
354 | * |
355 | * User BPF's register A is mapped to our BPF register 6, user BPF | |
356 | * register X is mapped to BPF register 7; frame pointer is always | |
357 | * register 10; Context 'void *ctx' is stored in register 1, that is, | |
358 | * for socket filters: ctx == 'struct sk_buff *', for seccomp: | |
359 | * ctx == 'struct seccomp_data *'. | |
360 | */ | |
d9e12f42 NS |
361 | static int bpf_convert_filter(struct sock_filter *prog, int len, |
362 | struct bpf_insn *new_prog, int *new_len) | |
bd4cf0ed AS |
363 | { |
364 | int new_flen = 0, pass = 0, target, i; | |
2695fb55 | 365 | struct bpf_insn *new_insn; |
bd4cf0ed AS |
366 | struct sock_filter *fp; |
367 | int *addrs = NULL; | |
368 | u8 bpf_src; | |
369 | ||
370 | BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK); | |
30743837 | 371 | BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG); |
bd4cf0ed | 372 | |
6f9a093b | 373 | if (len <= 0 || len > BPF_MAXINSNS) |
bd4cf0ed AS |
374 | return -EINVAL; |
375 | ||
376 | if (new_prog) { | |
658da937 DB |
377 | addrs = kcalloc(len, sizeof(*addrs), |
378 | GFP_KERNEL | __GFP_NOWARN); | |
bd4cf0ed AS |
379 | if (!addrs) |
380 | return -ENOMEM; | |
381 | } | |
382 | ||
383 | do_pass: | |
384 | new_insn = new_prog; | |
385 | fp = prog; | |
386 | ||
f8f6d679 DB |
387 | if (new_insn) |
388 | *new_insn = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1); | |
bd4cf0ed AS |
389 | new_insn++; |
390 | ||
391 | for (i = 0; i < len; fp++, i++) { | |
2695fb55 AS |
392 | struct bpf_insn tmp_insns[6] = { }; |
393 | struct bpf_insn *insn = tmp_insns; | |
bd4cf0ed AS |
394 | |
395 | if (addrs) | |
396 | addrs[i] = new_insn - new_prog; | |
397 | ||
398 | switch (fp->code) { | |
399 | /* All arithmetic insns and skb loads map as-is. */ | |
400 | case BPF_ALU | BPF_ADD | BPF_X: | |
401 | case BPF_ALU | BPF_ADD | BPF_K: | |
402 | case BPF_ALU | BPF_SUB | BPF_X: | |
403 | case BPF_ALU | BPF_SUB | BPF_K: | |
404 | case BPF_ALU | BPF_AND | BPF_X: | |
405 | case BPF_ALU | BPF_AND | BPF_K: | |
406 | case BPF_ALU | BPF_OR | BPF_X: | |
407 | case BPF_ALU | BPF_OR | BPF_K: | |
408 | case BPF_ALU | BPF_LSH | BPF_X: | |
409 | case BPF_ALU | BPF_LSH | BPF_K: | |
410 | case BPF_ALU | BPF_RSH | BPF_X: | |
411 | case BPF_ALU | BPF_RSH | BPF_K: | |
412 | case BPF_ALU | BPF_XOR | BPF_X: | |
413 | case BPF_ALU | BPF_XOR | BPF_K: | |
414 | case BPF_ALU | BPF_MUL | BPF_X: | |
415 | case BPF_ALU | BPF_MUL | BPF_K: | |
416 | case BPF_ALU | BPF_DIV | BPF_X: | |
417 | case BPF_ALU | BPF_DIV | BPF_K: | |
418 | case BPF_ALU | BPF_MOD | BPF_X: | |
419 | case BPF_ALU | BPF_MOD | BPF_K: | |
420 | case BPF_ALU | BPF_NEG: | |
421 | case BPF_LD | BPF_ABS | BPF_W: | |
422 | case BPF_LD | BPF_ABS | BPF_H: | |
423 | case BPF_LD | BPF_ABS | BPF_B: | |
424 | case BPF_LD | BPF_IND | BPF_W: | |
425 | case BPF_LD | BPF_IND | BPF_H: | |
426 | case BPF_LD | BPF_IND | BPF_B: | |
427 | /* Check for overloaded BPF extension and | |
428 | * directly convert it if found, otherwise | |
429 | * just move on with mapping. | |
430 | */ | |
431 | if (BPF_CLASS(fp->code) == BPF_LD && | |
432 | BPF_MODE(fp->code) == BPF_ABS && | |
433 | convert_bpf_extensions(fp, &insn)) | |
434 | break; | |
435 | ||
f8f6d679 | 436 | *insn = BPF_RAW_INSN(fp->code, BPF_REG_A, BPF_REG_X, 0, fp->k); |
bd4cf0ed AS |
437 | break; |
438 | ||
f8f6d679 DB |
439 | /* Jump transformation cannot use BPF block macros |
440 | * everywhere as offset calculation and target updates | |
441 | * require a bit more work than the rest, i.e. jump | |
442 | * opcodes map as-is, but offsets need adjustment. | |
443 | */ | |
444 | ||
445 | #define BPF_EMIT_JMP \ | |
bd4cf0ed AS |
446 | do { \ |
447 | if (target >= len || target < 0) \ | |
448 | goto err; \ | |
449 | insn->off = addrs ? addrs[target] - addrs[i] - 1 : 0; \ | |
450 | /* Adjust pc relative offset for 2nd or 3rd insn. */ \ | |
451 | insn->off -= insn - tmp_insns; \ | |
452 | } while (0) | |
453 | ||
f8f6d679 DB |
454 | case BPF_JMP | BPF_JA: |
455 | target = i + fp->k + 1; | |
456 | insn->code = fp->code; | |
457 | BPF_EMIT_JMP; | |
bd4cf0ed AS |
458 | break; |
459 | ||
460 | case BPF_JMP | BPF_JEQ | BPF_K: | |
461 | case BPF_JMP | BPF_JEQ | BPF_X: | |
462 | case BPF_JMP | BPF_JSET | BPF_K: | |
463 | case BPF_JMP | BPF_JSET | BPF_X: | |
464 | case BPF_JMP | BPF_JGT | BPF_K: | |
465 | case BPF_JMP | BPF_JGT | BPF_X: | |
466 | case BPF_JMP | BPF_JGE | BPF_K: | |
467 | case BPF_JMP | BPF_JGE | BPF_X: | |
468 | if (BPF_SRC(fp->code) == BPF_K && (int) fp->k < 0) { | |
469 | /* BPF immediates are signed, zero extend | |
470 | * immediate into tmp register and use it | |
471 | * in compare insn. | |
472 | */ | |
f8f6d679 | 473 | *insn++ = BPF_MOV32_IMM(BPF_REG_TMP, fp->k); |
bd4cf0ed | 474 | |
e430f34e AS |
475 | insn->dst_reg = BPF_REG_A; |
476 | insn->src_reg = BPF_REG_TMP; | |
bd4cf0ed AS |
477 | bpf_src = BPF_X; |
478 | } else { | |
e430f34e AS |
479 | insn->dst_reg = BPF_REG_A; |
480 | insn->src_reg = BPF_REG_X; | |
bd4cf0ed AS |
481 | insn->imm = fp->k; |
482 | bpf_src = BPF_SRC(fp->code); | |
1da177e4 | 483 | } |
bd4cf0ed AS |
484 | |
485 | /* Common case where 'jump_false' is next insn. */ | |
486 | if (fp->jf == 0) { | |
487 | insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src; | |
488 | target = i + fp->jt + 1; | |
f8f6d679 | 489 | BPF_EMIT_JMP; |
bd4cf0ed | 490 | break; |
1da177e4 | 491 | } |
bd4cf0ed AS |
492 | |
493 | /* Convert JEQ into JNE when 'jump_true' is next insn. */ | |
494 | if (fp->jt == 0 && BPF_OP(fp->code) == BPF_JEQ) { | |
495 | insn->code = BPF_JMP | BPF_JNE | bpf_src; | |
496 | target = i + fp->jf + 1; | |
f8f6d679 | 497 | BPF_EMIT_JMP; |
bd4cf0ed | 498 | break; |
0b05b2a4 | 499 | } |
bd4cf0ed AS |
500 | |
501 | /* Other jumps are mapped into two insns: Jxx and JA. */ | |
502 | target = i + fp->jt + 1; | |
503 | insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src; | |
f8f6d679 | 504 | BPF_EMIT_JMP; |
bd4cf0ed AS |
505 | insn++; |
506 | ||
507 | insn->code = BPF_JMP | BPF_JA; | |
508 | target = i + fp->jf + 1; | |
f8f6d679 | 509 | BPF_EMIT_JMP; |
bd4cf0ed AS |
510 | break; |
511 | ||
512 | /* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */ | |
513 | case BPF_LDX | BPF_MSH | BPF_B: | |
9739eef1 | 514 | /* tmp = A */ |
f8f6d679 | 515 | *insn++ = BPF_MOV64_REG(BPF_REG_TMP, BPF_REG_A); |
1268e253 | 516 | /* A = BPF_R0 = *(u8 *) (skb->data + K) */ |
f8f6d679 | 517 | *insn++ = BPF_LD_ABS(BPF_B, fp->k); |
9739eef1 | 518 | /* A &= 0xf */ |
f8f6d679 | 519 | *insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 0xf); |
9739eef1 | 520 | /* A <<= 2 */ |
f8f6d679 | 521 | *insn++ = BPF_ALU32_IMM(BPF_LSH, BPF_REG_A, 2); |
9739eef1 | 522 | /* X = A */ |
f8f6d679 | 523 | *insn++ = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A); |
9739eef1 | 524 | /* A = tmp */ |
f8f6d679 | 525 | *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_TMP); |
bd4cf0ed AS |
526 | break; |
527 | ||
528 | /* RET_K, RET_A are remaped into 2 insns. */ | |
529 | case BPF_RET | BPF_A: | |
530 | case BPF_RET | BPF_K: | |
f8f6d679 DB |
531 | *insn++ = BPF_MOV32_RAW(BPF_RVAL(fp->code) == BPF_K ? |
532 | BPF_K : BPF_X, BPF_REG_0, | |
533 | BPF_REG_A, fp->k); | |
9739eef1 | 534 | *insn = BPF_EXIT_INSN(); |
bd4cf0ed AS |
535 | break; |
536 | ||
537 | /* Store to stack. */ | |
538 | case BPF_ST: | |
539 | case BPF_STX: | |
f8f6d679 DB |
540 | *insn = BPF_STX_MEM(BPF_W, BPF_REG_FP, BPF_CLASS(fp->code) == |
541 | BPF_ST ? BPF_REG_A : BPF_REG_X, | |
542 | -(BPF_MEMWORDS - fp->k) * 4); | |
bd4cf0ed AS |
543 | break; |
544 | ||
545 | /* Load from stack. */ | |
546 | case BPF_LD | BPF_MEM: | |
547 | case BPF_LDX | BPF_MEM: | |
f8f6d679 DB |
548 | *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ? |
549 | BPF_REG_A : BPF_REG_X, BPF_REG_FP, | |
550 | -(BPF_MEMWORDS - fp->k) * 4); | |
bd4cf0ed AS |
551 | break; |
552 | ||
553 | /* A = K or X = K */ | |
554 | case BPF_LD | BPF_IMM: | |
555 | case BPF_LDX | BPF_IMM: | |
f8f6d679 DB |
556 | *insn = BPF_MOV32_IMM(BPF_CLASS(fp->code) == BPF_LD ? |
557 | BPF_REG_A : BPF_REG_X, fp->k); | |
bd4cf0ed AS |
558 | break; |
559 | ||
560 | /* X = A */ | |
561 | case BPF_MISC | BPF_TAX: | |
f8f6d679 | 562 | *insn = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A); |
bd4cf0ed AS |
563 | break; |
564 | ||
565 | /* A = X */ | |
566 | case BPF_MISC | BPF_TXA: | |
f8f6d679 | 567 | *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_X); |
bd4cf0ed AS |
568 | break; |
569 | ||
570 | /* A = skb->len or X = skb->len */ | |
571 | case BPF_LD | BPF_W | BPF_LEN: | |
572 | case BPF_LDX | BPF_W | BPF_LEN: | |
f8f6d679 DB |
573 | *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ? |
574 | BPF_REG_A : BPF_REG_X, BPF_REG_CTX, | |
575 | offsetof(struct sk_buff, len)); | |
bd4cf0ed AS |
576 | break; |
577 | ||
f8f6d679 | 578 | /* Access seccomp_data fields. */ |
bd4cf0ed | 579 | case BPF_LDX | BPF_ABS | BPF_W: |
9739eef1 AS |
580 | /* A = *(u32 *) (ctx + K) */ |
581 | *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, fp->k); | |
bd4cf0ed AS |
582 | break; |
583 | ||
ca9f1fd2 | 584 | /* Unknown instruction. */ |
1da177e4 | 585 | default: |
bd4cf0ed | 586 | goto err; |
1da177e4 | 587 | } |
bd4cf0ed AS |
588 | |
589 | insn++; | |
590 | if (new_prog) | |
591 | memcpy(new_insn, tmp_insns, | |
592 | sizeof(*insn) * (insn - tmp_insns)); | |
bd4cf0ed | 593 | new_insn += insn - tmp_insns; |
1da177e4 LT |
594 | } |
595 | ||
bd4cf0ed AS |
596 | if (!new_prog) { |
597 | /* Only calculating new length. */ | |
598 | *new_len = new_insn - new_prog; | |
599 | return 0; | |
600 | } | |
601 | ||
602 | pass++; | |
603 | if (new_flen != new_insn - new_prog) { | |
604 | new_flen = new_insn - new_prog; | |
605 | if (pass > 2) | |
606 | goto err; | |
bd4cf0ed AS |
607 | goto do_pass; |
608 | } | |
609 | ||
610 | kfree(addrs); | |
611 | BUG_ON(*new_len != new_flen); | |
1da177e4 | 612 | return 0; |
bd4cf0ed AS |
613 | err: |
614 | kfree(addrs); | |
615 | return -EINVAL; | |
1da177e4 LT |
616 | } |
617 | ||
bd4cf0ed | 618 | /* Security: |
bd4cf0ed | 619 | * |
2d5311e4 | 620 | * As we dont want to clear mem[] array for each packet going through |
8ea6e345 | 621 | * __bpf_prog_run(), we check that filter loaded by user never try to read |
2d5311e4 | 622 | * a cell if not previously written, and we check all branches to be sure |
25985edc | 623 | * a malicious user doesn't try to abuse us. |
2d5311e4 | 624 | */ |
ec31a05c | 625 | static int check_load_and_stores(const struct sock_filter *filter, int flen) |
2d5311e4 | 626 | { |
34805931 | 627 | u16 *masks, memvalid = 0; /* One bit per cell, 16 cells */ |
2d5311e4 ED |
628 | int pc, ret = 0; |
629 | ||
630 | BUILD_BUG_ON(BPF_MEMWORDS > 16); | |
34805931 | 631 | |
99e72a0f | 632 | masks = kmalloc_array(flen, sizeof(*masks), GFP_KERNEL); |
2d5311e4 ED |
633 | if (!masks) |
634 | return -ENOMEM; | |
34805931 | 635 | |
2d5311e4 ED |
636 | memset(masks, 0xff, flen * sizeof(*masks)); |
637 | ||
638 | for (pc = 0; pc < flen; pc++) { | |
639 | memvalid &= masks[pc]; | |
640 | ||
641 | switch (filter[pc].code) { | |
34805931 DB |
642 | case BPF_ST: |
643 | case BPF_STX: | |
2d5311e4 ED |
644 | memvalid |= (1 << filter[pc].k); |
645 | break; | |
34805931 DB |
646 | case BPF_LD | BPF_MEM: |
647 | case BPF_LDX | BPF_MEM: | |
2d5311e4 ED |
648 | if (!(memvalid & (1 << filter[pc].k))) { |
649 | ret = -EINVAL; | |
650 | goto error; | |
651 | } | |
652 | break; | |
34805931 DB |
653 | case BPF_JMP | BPF_JA: |
654 | /* A jump must set masks on target */ | |
2d5311e4 ED |
655 | masks[pc + 1 + filter[pc].k] &= memvalid; |
656 | memvalid = ~0; | |
657 | break; | |
34805931 DB |
658 | case BPF_JMP | BPF_JEQ | BPF_K: |
659 | case BPF_JMP | BPF_JEQ | BPF_X: | |
660 | case BPF_JMP | BPF_JGE | BPF_K: | |
661 | case BPF_JMP | BPF_JGE | BPF_X: | |
662 | case BPF_JMP | BPF_JGT | BPF_K: | |
663 | case BPF_JMP | BPF_JGT | BPF_X: | |
664 | case BPF_JMP | BPF_JSET | BPF_K: | |
665 | case BPF_JMP | BPF_JSET | BPF_X: | |
666 | /* A jump must set masks on targets */ | |
2d5311e4 ED |
667 | masks[pc + 1 + filter[pc].jt] &= memvalid; |
668 | masks[pc + 1 + filter[pc].jf] &= memvalid; | |
669 | memvalid = ~0; | |
670 | break; | |
671 | } | |
672 | } | |
673 | error: | |
674 | kfree(masks); | |
675 | return ret; | |
676 | } | |
677 | ||
34805931 DB |
678 | static bool chk_code_allowed(u16 code_to_probe) |
679 | { | |
680 | static const bool codes[] = { | |
681 | /* 32 bit ALU operations */ | |
682 | [BPF_ALU | BPF_ADD | BPF_K] = true, | |
683 | [BPF_ALU | BPF_ADD | BPF_X] = true, | |
684 | [BPF_ALU | BPF_SUB | BPF_K] = true, | |
685 | [BPF_ALU | BPF_SUB | BPF_X] = true, | |
686 | [BPF_ALU | BPF_MUL | BPF_K] = true, | |
687 | [BPF_ALU | BPF_MUL | BPF_X] = true, | |
688 | [BPF_ALU | BPF_DIV | BPF_K] = true, | |
689 | [BPF_ALU | BPF_DIV | BPF_X] = true, | |
690 | [BPF_ALU | BPF_MOD | BPF_K] = true, | |
691 | [BPF_ALU | BPF_MOD | BPF_X] = true, | |
692 | [BPF_ALU | BPF_AND | BPF_K] = true, | |
693 | [BPF_ALU | BPF_AND | BPF_X] = true, | |
694 | [BPF_ALU | BPF_OR | BPF_K] = true, | |
695 | [BPF_ALU | BPF_OR | BPF_X] = true, | |
696 | [BPF_ALU | BPF_XOR | BPF_K] = true, | |
697 | [BPF_ALU | BPF_XOR | BPF_X] = true, | |
698 | [BPF_ALU | BPF_LSH | BPF_K] = true, | |
699 | [BPF_ALU | BPF_LSH | BPF_X] = true, | |
700 | [BPF_ALU | BPF_RSH | BPF_K] = true, | |
701 | [BPF_ALU | BPF_RSH | BPF_X] = true, | |
702 | [BPF_ALU | BPF_NEG] = true, | |
703 | /* Load instructions */ | |
704 | [BPF_LD | BPF_W | BPF_ABS] = true, | |
705 | [BPF_LD | BPF_H | BPF_ABS] = true, | |
706 | [BPF_LD | BPF_B | BPF_ABS] = true, | |
707 | [BPF_LD | BPF_W | BPF_LEN] = true, | |
708 | [BPF_LD | BPF_W | BPF_IND] = true, | |
709 | [BPF_LD | BPF_H | BPF_IND] = true, | |
710 | [BPF_LD | BPF_B | BPF_IND] = true, | |
711 | [BPF_LD | BPF_IMM] = true, | |
712 | [BPF_LD | BPF_MEM] = true, | |
713 | [BPF_LDX | BPF_W | BPF_LEN] = true, | |
714 | [BPF_LDX | BPF_B | BPF_MSH] = true, | |
715 | [BPF_LDX | BPF_IMM] = true, | |
716 | [BPF_LDX | BPF_MEM] = true, | |
717 | /* Store instructions */ | |
718 | [BPF_ST] = true, | |
719 | [BPF_STX] = true, | |
720 | /* Misc instructions */ | |
721 | [BPF_MISC | BPF_TAX] = true, | |
722 | [BPF_MISC | BPF_TXA] = true, | |
723 | /* Return instructions */ | |
724 | [BPF_RET | BPF_K] = true, | |
725 | [BPF_RET | BPF_A] = true, | |
726 | /* Jump instructions */ | |
727 | [BPF_JMP | BPF_JA] = true, | |
728 | [BPF_JMP | BPF_JEQ | BPF_K] = true, | |
729 | [BPF_JMP | BPF_JEQ | BPF_X] = true, | |
730 | [BPF_JMP | BPF_JGE | BPF_K] = true, | |
731 | [BPF_JMP | BPF_JGE | BPF_X] = true, | |
732 | [BPF_JMP | BPF_JGT | BPF_K] = true, | |
733 | [BPF_JMP | BPF_JGT | BPF_X] = true, | |
734 | [BPF_JMP | BPF_JSET | BPF_K] = true, | |
735 | [BPF_JMP | BPF_JSET | BPF_X] = true, | |
736 | }; | |
737 | ||
738 | if (code_to_probe >= ARRAY_SIZE(codes)) | |
739 | return false; | |
740 | ||
741 | return codes[code_to_probe]; | |
742 | } | |
743 | ||
1da177e4 | 744 | /** |
4df95ff4 | 745 | * bpf_check_classic - verify socket filter code |
1da177e4 LT |
746 | * @filter: filter to verify |
747 | * @flen: length of filter | |
748 | * | |
749 | * Check the user's filter code. If we let some ugly | |
750 | * filter code slip through kaboom! The filter must contain | |
93699863 KK |
751 | * no references or jumps that are out of range, no illegal |
752 | * instructions, and must end with a RET instruction. | |
1da177e4 | 753 | * |
7b11f69f KK |
754 | * All jumps are forward as they are not signed. |
755 | * | |
756 | * Returns 0 if the rule set is legal or -EINVAL if not. | |
1da177e4 | 757 | */ |
d9e12f42 NS |
758 | static int bpf_check_classic(const struct sock_filter *filter, |
759 | unsigned int flen) | |
1da177e4 | 760 | { |
aa1113d9 | 761 | bool anc_found; |
34805931 | 762 | int pc; |
1da177e4 | 763 | |
1b93ae64 | 764 | if (flen == 0 || flen > BPF_MAXINSNS) |
1da177e4 LT |
765 | return -EINVAL; |
766 | ||
34805931 | 767 | /* Check the filter code now */ |
1da177e4 | 768 | for (pc = 0; pc < flen; pc++) { |
ec31a05c | 769 | const struct sock_filter *ftest = &filter[pc]; |
93699863 | 770 | |
34805931 DB |
771 | /* May we actually operate on this code? */ |
772 | if (!chk_code_allowed(ftest->code)) | |
cba328fc | 773 | return -EINVAL; |
34805931 | 774 | |
93699863 | 775 | /* Some instructions need special checks */ |
34805931 DB |
776 | switch (ftest->code) { |
777 | case BPF_ALU | BPF_DIV | BPF_K: | |
778 | case BPF_ALU | BPF_MOD | BPF_K: | |
779 | /* Check for division by zero */ | |
b6069a95 ED |
780 | if (ftest->k == 0) |
781 | return -EINVAL; | |
782 | break; | |
34805931 DB |
783 | case BPF_LD | BPF_MEM: |
784 | case BPF_LDX | BPF_MEM: | |
785 | case BPF_ST: | |
786 | case BPF_STX: | |
787 | /* Check for invalid memory addresses */ | |
93699863 KK |
788 | if (ftest->k >= BPF_MEMWORDS) |
789 | return -EINVAL; | |
790 | break; | |
34805931 DB |
791 | case BPF_JMP | BPF_JA: |
792 | /* Note, the large ftest->k might cause loops. | |
93699863 KK |
793 | * Compare this with conditional jumps below, |
794 | * where offsets are limited. --ANK (981016) | |
795 | */ | |
34805931 | 796 | if (ftest->k >= (unsigned int)(flen - pc - 1)) |
93699863 | 797 | return -EINVAL; |
01f2f3f6 | 798 | break; |
34805931 DB |
799 | case BPF_JMP | BPF_JEQ | BPF_K: |
800 | case BPF_JMP | BPF_JEQ | BPF_X: | |
801 | case BPF_JMP | BPF_JGE | BPF_K: | |
802 | case BPF_JMP | BPF_JGE | BPF_X: | |
803 | case BPF_JMP | BPF_JGT | BPF_K: | |
804 | case BPF_JMP | BPF_JGT | BPF_X: | |
805 | case BPF_JMP | BPF_JSET | BPF_K: | |
806 | case BPF_JMP | BPF_JSET | BPF_X: | |
807 | /* Both conditionals must be safe */ | |
e35bedf3 | 808 | if (pc + ftest->jt + 1 >= flen || |
93699863 KK |
809 | pc + ftest->jf + 1 >= flen) |
810 | return -EINVAL; | |
cba328fc | 811 | break; |
34805931 DB |
812 | case BPF_LD | BPF_W | BPF_ABS: |
813 | case BPF_LD | BPF_H | BPF_ABS: | |
814 | case BPF_LD | BPF_B | BPF_ABS: | |
aa1113d9 | 815 | anc_found = false; |
34805931 DB |
816 | if (bpf_anc_helper(ftest) & BPF_ANC) |
817 | anc_found = true; | |
818 | /* Ancillary operation unknown or unsupported */ | |
aa1113d9 DB |
819 | if (anc_found == false && ftest->k >= SKF_AD_OFF) |
820 | return -EINVAL; | |
01f2f3f6 HPP |
821 | } |
822 | } | |
93699863 | 823 | |
34805931 | 824 | /* Last instruction must be a RET code */ |
01f2f3f6 | 825 | switch (filter[flen - 1].code) { |
34805931 DB |
826 | case BPF_RET | BPF_K: |
827 | case BPF_RET | BPF_A: | |
2d5311e4 | 828 | return check_load_and_stores(filter, flen); |
cba328fc | 829 | } |
34805931 | 830 | |
cba328fc | 831 | return -EINVAL; |
1da177e4 LT |
832 | } |
833 | ||
7ae457c1 AS |
834 | static int bpf_prog_store_orig_filter(struct bpf_prog *fp, |
835 | const struct sock_fprog *fprog) | |
a3ea269b | 836 | { |
009937e7 | 837 | unsigned int fsize = bpf_classic_proglen(fprog); |
a3ea269b DB |
838 | struct sock_fprog_kern *fkprog; |
839 | ||
840 | fp->orig_prog = kmalloc(sizeof(*fkprog), GFP_KERNEL); | |
841 | if (!fp->orig_prog) | |
842 | return -ENOMEM; | |
843 | ||
844 | fkprog = fp->orig_prog; | |
845 | fkprog->len = fprog->len; | |
658da937 DB |
846 | |
847 | fkprog->filter = kmemdup(fp->insns, fsize, | |
848 | GFP_KERNEL | __GFP_NOWARN); | |
a3ea269b DB |
849 | if (!fkprog->filter) { |
850 | kfree(fp->orig_prog); | |
851 | return -ENOMEM; | |
852 | } | |
853 | ||
854 | return 0; | |
855 | } | |
856 | ||
7ae457c1 | 857 | static void bpf_release_orig_filter(struct bpf_prog *fp) |
a3ea269b DB |
858 | { |
859 | struct sock_fprog_kern *fprog = fp->orig_prog; | |
860 | ||
861 | if (fprog) { | |
862 | kfree(fprog->filter); | |
863 | kfree(fprog); | |
864 | } | |
865 | } | |
866 | ||
7ae457c1 AS |
867 | static void __bpf_prog_release(struct bpf_prog *prog) |
868 | { | |
24701ece | 869 | if (prog->type == BPF_PROG_TYPE_SOCKET_FILTER) { |
89aa0758 AS |
870 | bpf_prog_put(prog); |
871 | } else { | |
872 | bpf_release_orig_filter(prog); | |
873 | bpf_prog_free(prog); | |
874 | } | |
7ae457c1 AS |
875 | } |
876 | ||
34c5bd66 PN |
877 | static void __sk_filter_release(struct sk_filter *fp) |
878 | { | |
7ae457c1 AS |
879 | __bpf_prog_release(fp->prog); |
880 | kfree(fp); | |
34c5bd66 PN |
881 | } |
882 | ||
47e958ea | 883 | /** |
46bcf14f | 884 | * sk_filter_release_rcu - Release a socket filter by rcu_head |
47e958ea PE |
885 | * @rcu: rcu_head that contains the sk_filter to free |
886 | */ | |
fbc907f0 | 887 | static void sk_filter_release_rcu(struct rcu_head *rcu) |
47e958ea PE |
888 | { |
889 | struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); | |
890 | ||
34c5bd66 | 891 | __sk_filter_release(fp); |
47e958ea | 892 | } |
fbc907f0 DB |
893 | |
894 | /** | |
895 | * sk_filter_release - release a socket filter | |
896 | * @fp: filter to remove | |
897 | * | |
898 | * Remove a filter from a socket and release its resources. | |
899 | */ | |
900 | static void sk_filter_release(struct sk_filter *fp) | |
901 | { | |
902 | if (atomic_dec_and_test(&fp->refcnt)) | |
903 | call_rcu(&fp->rcu, sk_filter_release_rcu); | |
904 | } | |
905 | ||
906 | void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp) | |
907 | { | |
7ae457c1 | 908 | u32 filter_size = bpf_prog_size(fp->prog->len); |
fbc907f0 | 909 | |
278571ba AS |
910 | atomic_sub(filter_size, &sk->sk_omem_alloc); |
911 | sk_filter_release(fp); | |
fbc907f0 | 912 | } |
47e958ea | 913 | |
278571ba AS |
914 | /* try to charge the socket memory if there is space available |
915 | * return true on success | |
916 | */ | |
917 | bool sk_filter_charge(struct sock *sk, struct sk_filter *fp) | |
bd4cf0ed | 918 | { |
7ae457c1 | 919 | u32 filter_size = bpf_prog_size(fp->prog->len); |
278571ba AS |
920 | |
921 | /* same check as in sock_kmalloc() */ | |
922 | if (filter_size <= sysctl_optmem_max && | |
923 | atomic_read(&sk->sk_omem_alloc) + filter_size < sysctl_optmem_max) { | |
924 | atomic_inc(&fp->refcnt); | |
925 | atomic_add(filter_size, &sk->sk_omem_alloc); | |
926 | return true; | |
bd4cf0ed | 927 | } |
278571ba | 928 | return false; |
bd4cf0ed AS |
929 | } |
930 | ||
7ae457c1 | 931 | static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp) |
bd4cf0ed AS |
932 | { |
933 | struct sock_filter *old_prog; | |
7ae457c1 | 934 | struct bpf_prog *old_fp; |
34805931 | 935 | int err, new_len, old_len = fp->len; |
bd4cf0ed AS |
936 | |
937 | /* We are free to overwrite insns et al right here as it | |
938 | * won't be used at this point in time anymore internally | |
939 | * after the migration to the internal BPF instruction | |
940 | * representation. | |
941 | */ | |
942 | BUILD_BUG_ON(sizeof(struct sock_filter) != | |
2695fb55 | 943 | sizeof(struct bpf_insn)); |
bd4cf0ed | 944 | |
bd4cf0ed AS |
945 | /* Conversion cannot happen on overlapping memory areas, |
946 | * so we need to keep the user BPF around until the 2nd | |
947 | * pass. At this time, the user BPF is stored in fp->insns. | |
948 | */ | |
949 | old_prog = kmemdup(fp->insns, old_len * sizeof(struct sock_filter), | |
658da937 | 950 | GFP_KERNEL | __GFP_NOWARN); |
bd4cf0ed AS |
951 | if (!old_prog) { |
952 | err = -ENOMEM; | |
953 | goto out_err; | |
954 | } | |
955 | ||
956 | /* 1st pass: calculate the new program length. */ | |
8fb575ca | 957 | err = bpf_convert_filter(old_prog, old_len, NULL, &new_len); |
bd4cf0ed AS |
958 | if (err) |
959 | goto out_err_free; | |
960 | ||
961 | /* Expand fp for appending the new filter representation. */ | |
962 | old_fp = fp; | |
60a3b225 | 963 | fp = bpf_prog_realloc(old_fp, bpf_prog_size(new_len), 0); |
bd4cf0ed AS |
964 | if (!fp) { |
965 | /* The old_fp is still around in case we couldn't | |
966 | * allocate new memory, so uncharge on that one. | |
967 | */ | |
968 | fp = old_fp; | |
969 | err = -ENOMEM; | |
970 | goto out_err_free; | |
971 | } | |
972 | ||
bd4cf0ed AS |
973 | fp->len = new_len; |
974 | ||
2695fb55 | 975 | /* 2nd pass: remap sock_filter insns into bpf_insn insns. */ |
8fb575ca | 976 | err = bpf_convert_filter(old_prog, old_len, fp->insnsi, &new_len); |
bd4cf0ed | 977 | if (err) |
8fb575ca | 978 | /* 2nd bpf_convert_filter() can fail only if it fails |
bd4cf0ed AS |
979 | * to allocate memory, remapping must succeed. Note, |
980 | * that at this time old_fp has already been released | |
278571ba | 981 | * by krealloc(). |
bd4cf0ed AS |
982 | */ |
983 | goto out_err_free; | |
984 | ||
7ae457c1 | 985 | bpf_prog_select_runtime(fp); |
5fe821a9 | 986 | |
bd4cf0ed AS |
987 | kfree(old_prog); |
988 | return fp; | |
989 | ||
990 | out_err_free: | |
991 | kfree(old_prog); | |
992 | out_err: | |
7ae457c1 | 993 | __bpf_prog_release(fp); |
bd4cf0ed AS |
994 | return ERR_PTR(err); |
995 | } | |
996 | ||
ac67eb2c DB |
997 | static struct bpf_prog *bpf_prepare_filter(struct bpf_prog *fp, |
998 | bpf_aux_classic_check_t trans) | |
302d6637 JP |
999 | { |
1000 | int err; | |
1001 | ||
bd4cf0ed | 1002 | fp->bpf_func = NULL; |
286aad3c | 1003 | fp->jited = false; |
302d6637 | 1004 | |
4df95ff4 | 1005 | err = bpf_check_classic(fp->insns, fp->len); |
418c96ac | 1006 | if (err) { |
7ae457c1 | 1007 | __bpf_prog_release(fp); |
bd4cf0ed | 1008 | return ERR_PTR(err); |
418c96ac | 1009 | } |
302d6637 | 1010 | |
4ae92bc7 NS |
1011 | /* There might be additional checks and transformations |
1012 | * needed on classic filters, f.e. in case of seccomp. | |
1013 | */ | |
1014 | if (trans) { | |
1015 | err = trans(fp->insns, fp->len); | |
1016 | if (err) { | |
1017 | __bpf_prog_release(fp); | |
1018 | return ERR_PTR(err); | |
1019 | } | |
1020 | } | |
1021 | ||
bd4cf0ed AS |
1022 | /* Probe if we can JIT compile the filter and if so, do |
1023 | * the compilation of the filter. | |
1024 | */ | |
302d6637 | 1025 | bpf_jit_compile(fp); |
bd4cf0ed AS |
1026 | |
1027 | /* JIT compiler couldn't process this filter, so do the | |
1028 | * internal BPF translation for the optimized interpreter. | |
1029 | */ | |
5fe821a9 | 1030 | if (!fp->jited) |
7ae457c1 | 1031 | fp = bpf_migrate_filter(fp); |
bd4cf0ed AS |
1032 | |
1033 | return fp; | |
302d6637 JP |
1034 | } |
1035 | ||
1036 | /** | |
7ae457c1 | 1037 | * bpf_prog_create - create an unattached filter |
c6c4b97c | 1038 | * @pfp: the unattached filter that is created |
677a9fd3 | 1039 | * @fprog: the filter program |
302d6637 | 1040 | * |
c6c4b97c | 1041 | * Create a filter independent of any socket. We first run some |
302d6637 JP |
1042 | * sanity checks on it to make sure it does not explode on us later. |
1043 | * If an error occurs or there is insufficient memory for the filter | |
1044 | * a negative errno code is returned. On success the return is zero. | |
1045 | */ | |
7ae457c1 | 1046 | int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog) |
302d6637 | 1047 | { |
009937e7 | 1048 | unsigned int fsize = bpf_classic_proglen(fprog); |
7ae457c1 | 1049 | struct bpf_prog *fp; |
302d6637 JP |
1050 | |
1051 | /* Make sure new filter is there and in the right amounts. */ | |
1052 | if (fprog->filter == NULL) | |
1053 | return -EINVAL; | |
1054 | ||
60a3b225 | 1055 | fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0); |
302d6637 JP |
1056 | if (!fp) |
1057 | return -ENOMEM; | |
a3ea269b | 1058 | |
302d6637 JP |
1059 | memcpy(fp->insns, fprog->filter, fsize); |
1060 | ||
302d6637 | 1061 | fp->len = fprog->len; |
a3ea269b DB |
1062 | /* Since unattached filters are not copied back to user |
1063 | * space through sk_get_filter(), we do not need to hold | |
1064 | * a copy here, and can spare us the work. | |
1065 | */ | |
1066 | fp->orig_prog = NULL; | |
302d6637 | 1067 | |
7ae457c1 | 1068 | /* bpf_prepare_filter() already takes care of freeing |
bd4cf0ed AS |
1069 | * memory in case something goes wrong. |
1070 | */ | |
4ae92bc7 | 1071 | fp = bpf_prepare_filter(fp, NULL); |
bd4cf0ed AS |
1072 | if (IS_ERR(fp)) |
1073 | return PTR_ERR(fp); | |
302d6637 JP |
1074 | |
1075 | *pfp = fp; | |
1076 | return 0; | |
302d6637 | 1077 | } |
7ae457c1 | 1078 | EXPORT_SYMBOL_GPL(bpf_prog_create); |
302d6637 | 1079 | |
ac67eb2c DB |
1080 | /** |
1081 | * bpf_prog_create_from_user - create an unattached filter from user buffer | |
1082 | * @pfp: the unattached filter that is created | |
1083 | * @fprog: the filter program | |
1084 | * @trans: post-classic verifier transformation handler | |
1085 | * | |
1086 | * This function effectively does the same as bpf_prog_create(), only | |
1087 | * that it builds up its insns buffer from user space provided buffer. | |
1088 | * It also allows for passing a bpf_aux_classic_check_t handler. | |
1089 | */ | |
1090 | int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog, | |
1091 | bpf_aux_classic_check_t trans) | |
1092 | { | |
1093 | unsigned int fsize = bpf_classic_proglen(fprog); | |
1094 | struct bpf_prog *fp; | |
1095 | ||
1096 | /* Make sure new filter is there and in the right amounts. */ | |
1097 | if (fprog->filter == NULL) | |
1098 | return -EINVAL; | |
1099 | ||
1100 | fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0); | |
1101 | if (!fp) | |
1102 | return -ENOMEM; | |
1103 | ||
1104 | if (copy_from_user(fp->insns, fprog->filter, fsize)) { | |
1105 | __bpf_prog_free(fp); | |
1106 | return -EFAULT; | |
1107 | } | |
1108 | ||
1109 | fp->len = fprog->len; | |
1110 | /* Since unattached filters are not copied back to user | |
1111 | * space through sk_get_filter(), we do not need to hold | |
1112 | * a copy here, and can spare us the work. | |
1113 | */ | |
1114 | fp->orig_prog = NULL; | |
1115 | ||
1116 | /* bpf_prepare_filter() already takes care of freeing | |
1117 | * memory in case something goes wrong. | |
1118 | */ | |
1119 | fp = bpf_prepare_filter(fp, trans); | |
1120 | if (IS_ERR(fp)) | |
1121 | return PTR_ERR(fp); | |
1122 | ||
1123 | *pfp = fp; | |
1124 | return 0; | |
1125 | } | |
1126 | ||
7ae457c1 | 1127 | void bpf_prog_destroy(struct bpf_prog *fp) |
302d6637 | 1128 | { |
7ae457c1 | 1129 | __bpf_prog_release(fp); |
302d6637 | 1130 | } |
7ae457c1 | 1131 | EXPORT_SYMBOL_GPL(bpf_prog_destroy); |
302d6637 | 1132 | |
49b31e57 DB |
1133 | static int __sk_attach_prog(struct bpf_prog *prog, struct sock *sk) |
1134 | { | |
1135 | struct sk_filter *fp, *old_fp; | |
1136 | ||
1137 | fp = kmalloc(sizeof(*fp), GFP_KERNEL); | |
1138 | if (!fp) | |
1139 | return -ENOMEM; | |
1140 | ||
1141 | fp->prog = prog; | |
1142 | atomic_set(&fp->refcnt, 0); | |
1143 | ||
1144 | if (!sk_filter_charge(sk, fp)) { | |
1145 | kfree(fp); | |
1146 | return -ENOMEM; | |
1147 | } | |
1148 | ||
1149 | old_fp = rcu_dereference_protected(sk->sk_filter, | |
1150 | sock_owned_by_user(sk)); | |
1151 | rcu_assign_pointer(sk->sk_filter, fp); | |
1152 | ||
1153 | if (old_fp) | |
1154 | sk_filter_uncharge(sk, old_fp); | |
1155 | ||
1156 | return 0; | |
1157 | } | |
1158 | ||
1da177e4 LT |
1159 | /** |
1160 | * sk_attach_filter - attach a socket filter | |
1161 | * @fprog: the filter program | |
1162 | * @sk: the socket to use | |
1163 | * | |
1164 | * Attach the user's filter code. We first run some sanity checks on | |
1165 | * it to make sure it does not explode on us later. If an error | |
1166 | * occurs or there is insufficient memory for the filter a negative | |
1167 | * errno code is returned. On success the return is zero. | |
1168 | */ | |
1169 | int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) | |
1170 | { | |
009937e7 | 1171 | unsigned int fsize = bpf_classic_proglen(fprog); |
7ae457c1 AS |
1172 | unsigned int bpf_fsize = bpf_prog_size(fprog->len); |
1173 | struct bpf_prog *prog; | |
1da177e4 LT |
1174 | int err; |
1175 | ||
d59577b6 VB |
1176 | if (sock_flag(sk, SOCK_FILTER_LOCKED)) |
1177 | return -EPERM; | |
1178 | ||
1da177e4 | 1179 | /* Make sure new filter is there and in the right amounts. */ |
e35bedf3 KK |
1180 | if (fprog->filter == NULL) |
1181 | return -EINVAL; | |
1da177e4 | 1182 | |
60a3b225 | 1183 | prog = bpf_prog_alloc(bpf_fsize, 0); |
7ae457c1 | 1184 | if (!prog) |
1da177e4 | 1185 | return -ENOMEM; |
a3ea269b | 1186 | |
7ae457c1 | 1187 | if (copy_from_user(prog->insns, fprog->filter, fsize)) { |
c0d1379a | 1188 | __bpf_prog_free(prog); |
1da177e4 LT |
1189 | return -EFAULT; |
1190 | } | |
1191 | ||
7ae457c1 | 1192 | prog->len = fprog->len; |
1da177e4 | 1193 | |
7ae457c1 | 1194 | err = bpf_prog_store_orig_filter(prog, fprog); |
a3ea269b | 1195 | if (err) { |
c0d1379a | 1196 | __bpf_prog_free(prog); |
a3ea269b DB |
1197 | return -ENOMEM; |
1198 | } | |
1199 | ||
7ae457c1 | 1200 | /* bpf_prepare_filter() already takes care of freeing |
bd4cf0ed AS |
1201 | * memory in case something goes wrong. |
1202 | */ | |
4ae92bc7 | 1203 | prog = bpf_prepare_filter(prog, NULL); |
7ae457c1 AS |
1204 | if (IS_ERR(prog)) |
1205 | return PTR_ERR(prog); | |
1206 | ||
49b31e57 DB |
1207 | err = __sk_attach_prog(prog, sk); |
1208 | if (err < 0) { | |
7ae457c1 | 1209 | __bpf_prog_release(prog); |
49b31e57 | 1210 | return err; |
278571ba AS |
1211 | } |
1212 | ||
d3904b73 | 1213 | return 0; |
1da177e4 | 1214 | } |
5ff3f073 | 1215 | EXPORT_SYMBOL_GPL(sk_attach_filter); |
1da177e4 | 1216 | |
89aa0758 AS |
1217 | int sk_attach_bpf(u32 ufd, struct sock *sk) |
1218 | { | |
89aa0758 | 1219 | struct bpf_prog *prog; |
49b31e57 | 1220 | int err; |
89aa0758 AS |
1221 | |
1222 | if (sock_flag(sk, SOCK_FILTER_LOCKED)) | |
1223 | return -EPERM; | |
1224 | ||
1225 | prog = bpf_prog_get(ufd); | |
198bf1b0 AS |
1226 | if (IS_ERR(prog)) |
1227 | return PTR_ERR(prog); | |
89aa0758 | 1228 | |
24701ece | 1229 | if (prog->type != BPF_PROG_TYPE_SOCKET_FILTER) { |
89aa0758 AS |
1230 | bpf_prog_put(prog); |
1231 | return -EINVAL; | |
1232 | } | |
1233 | ||
49b31e57 DB |
1234 | err = __sk_attach_prog(prog, sk); |
1235 | if (err < 0) { | |
89aa0758 | 1236 | bpf_prog_put(prog); |
49b31e57 | 1237 | return err; |
89aa0758 AS |
1238 | } |
1239 | ||
89aa0758 AS |
1240 | return 0; |
1241 | } | |
1242 | ||
91bc4822 AS |
1243 | #define BPF_RECOMPUTE_CSUM(flags) ((flags) & 1) |
1244 | ||
1245 | static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags) | |
608cd71a AS |
1246 | { |
1247 | struct sk_buff *skb = (struct sk_buff *) (long) r1; | |
a166151c | 1248 | int offset = (int) r2; |
608cd71a AS |
1249 | void *from = (void *) (long) r3; |
1250 | unsigned int len = (unsigned int) r4; | |
1251 | char buf[16]; | |
1252 | void *ptr; | |
1253 | ||
1254 | /* bpf verifier guarantees that: | |
1255 | * 'from' pointer points to bpf program stack | |
1256 | * 'len' bytes of it were initialized | |
1257 | * 'len' > 0 | |
1258 | * 'skb' is a valid pointer to 'struct sk_buff' | |
1259 | * | |
1260 | * so check for invalid 'offset' and too large 'len' | |
1261 | */ | |
a166151c | 1262 | if (unlikely((u32) offset > 0xffff || len > sizeof(buf))) |
608cd71a AS |
1263 | return -EFAULT; |
1264 | ||
a166151c | 1265 | if (unlikely(skb_cloned(skb) && |
3431205e | 1266 | !skb_clone_writable(skb, offset + len))) |
608cd71a AS |
1267 | return -EFAULT; |
1268 | ||
1269 | ptr = skb_header_pointer(skb, offset, len, buf); | |
1270 | if (unlikely(!ptr)) | |
1271 | return -EFAULT; | |
1272 | ||
91bc4822 AS |
1273 | if (BPF_RECOMPUTE_CSUM(flags)) |
1274 | skb_postpull_rcsum(skb, ptr, len); | |
608cd71a AS |
1275 | |
1276 | memcpy(ptr, from, len); | |
1277 | ||
1278 | if (ptr == buf) | |
1279 | /* skb_store_bits cannot return -EFAULT here */ | |
1280 | skb_store_bits(skb, offset, ptr, len); | |
1281 | ||
91bc4822 | 1282 | if (BPF_RECOMPUTE_CSUM(flags) && skb->ip_summed == CHECKSUM_COMPLETE) |
608cd71a AS |
1283 | skb->csum = csum_add(skb->csum, csum_partial(ptr, len, 0)); |
1284 | return 0; | |
1285 | } | |
1286 | ||
1287 | const struct bpf_func_proto bpf_skb_store_bytes_proto = { | |
1288 | .func = bpf_skb_store_bytes, | |
1289 | .gpl_only = false, | |
1290 | .ret_type = RET_INTEGER, | |
1291 | .arg1_type = ARG_PTR_TO_CTX, | |
1292 | .arg2_type = ARG_ANYTHING, | |
1293 | .arg3_type = ARG_PTR_TO_STACK, | |
1294 | .arg4_type = ARG_CONST_STACK_SIZE, | |
91bc4822 AS |
1295 | .arg5_type = ARG_ANYTHING, |
1296 | }; | |
1297 | ||
1298 | #define BPF_HEADER_FIELD_SIZE(flags) ((flags) & 0x0f) | |
1299 | #define BPF_IS_PSEUDO_HEADER(flags) ((flags) & 0x10) | |
1300 | ||
a166151c | 1301 | static u64 bpf_l3_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags) |
91bc4822 AS |
1302 | { |
1303 | struct sk_buff *skb = (struct sk_buff *) (long) r1; | |
a166151c | 1304 | int offset = (int) r2; |
91bc4822 AS |
1305 | __sum16 sum, *ptr; |
1306 | ||
a166151c | 1307 | if (unlikely((u32) offset > 0xffff)) |
91bc4822 AS |
1308 | return -EFAULT; |
1309 | ||
a166151c | 1310 | if (unlikely(skb_cloned(skb) && |
3431205e | 1311 | !skb_clone_writable(skb, offset + sizeof(sum)))) |
91bc4822 AS |
1312 | return -EFAULT; |
1313 | ||
1314 | ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum); | |
1315 | if (unlikely(!ptr)) | |
1316 | return -EFAULT; | |
1317 | ||
1318 | switch (BPF_HEADER_FIELD_SIZE(flags)) { | |
1319 | case 2: | |
1320 | csum_replace2(ptr, from, to); | |
1321 | break; | |
1322 | case 4: | |
1323 | csum_replace4(ptr, from, to); | |
1324 | break; | |
1325 | default: | |
1326 | return -EINVAL; | |
1327 | } | |
1328 | ||
1329 | if (ptr == &sum) | |
1330 | /* skb_store_bits guaranteed to not return -EFAULT here */ | |
1331 | skb_store_bits(skb, offset, ptr, sizeof(sum)); | |
1332 | ||
1333 | return 0; | |
1334 | } | |
1335 | ||
1336 | const struct bpf_func_proto bpf_l3_csum_replace_proto = { | |
1337 | .func = bpf_l3_csum_replace, | |
1338 | .gpl_only = false, | |
1339 | .ret_type = RET_INTEGER, | |
1340 | .arg1_type = ARG_PTR_TO_CTX, | |
1341 | .arg2_type = ARG_ANYTHING, | |
1342 | .arg3_type = ARG_ANYTHING, | |
1343 | .arg4_type = ARG_ANYTHING, | |
1344 | .arg5_type = ARG_ANYTHING, | |
1345 | }; | |
1346 | ||
a166151c | 1347 | static u64 bpf_l4_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags) |
91bc4822 AS |
1348 | { |
1349 | struct sk_buff *skb = (struct sk_buff *) (long) r1; | |
1350 | u32 is_pseudo = BPF_IS_PSEUDO_HEADER(flags); | |
a166151c | 1351 | int offset = (int) r2; |
91bc4822 AS |
1352 | __sum16 sum, *ptr; |
1353 | ||
a166151c | 1354 | if (unlikely((u32) offset > 0xffff)) |
91bc4822 AS |
1355 | return -EFAULT; |
1356 | ||
a166151c | 1357 | if (unlikely(skb_cloned(skb) && |
3431205e | 1358 | !skb_clone_writable(skb, offset + sizeof(sum)))) |
91bc4822 AS |
1359 | return -EFAULT; |
1360 | ||
1361 | ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum); | |
1362 | if (unlikely(!ptr)) | |
1363 | return -EFAULT; | |
1364 | ||
1365 | switch (BPF_HEADER_FIELD_SIZE(flags)) { | |
1366 | case 2: | |
1367 | inet_proto_csum_replace2(ptr, skb, from, to, is_pseudo); | |
1368 | break; | |
1369 | case 4: | |
1370 | inet_proto_csum_replace4(ptr, skb, from, to, is_pseudo); | |
1371 | break; | |
1372 | default: | |
1373 | return -EINVAL; | |
1374 | } | |
1375 | ||
1376 | if (ptr == &sum) | |
1377 | /* skb_store_bits guaranteed to not return -EFAULT here */ | |
1378 | skb_store_bits(skb, offset, ptr, sizeof(sum)); | |
1379 | ||
1380 | return 0; | |
1381 | } | |
1382 | ||
1383 | const struct bpf_func_proto bpf_l4_csum_replace_proto = { | |
1384 | .func = bpf_l4_csum_replace, | |
1385 | .gpl_only = false, | |
1386 | .ret_type = RET_INTEGER, | |
1387 | .arg1_type = ARG_PTR_TO_CTX, | |
1388 | .arg2_type = ARG_ANYTHING, | |
1389 | .arg3_type = ARG_ANYTHING, | |
1390 | .arg4_type = ARG_ANYTHING, | |
1391 | .arg5_type = ARG_ANYTHING, | |
608cd71a AS |
1392 | }; |
1393 | ||
3896d655 AS |
1394 | #define BPF_IS_REDIRECT_INGRESS(flags) ((flags) & 1) |
1395 | ||
1396 | static u64 bpf_clone_redirect(u64 r1, u64 ifindex, u64 flags, u64 r4, u64 r5) | |
1397 | { | |
1398 | struct sk_buff *skb = (struct sk_buff *) (long) r1, *skb2; | |
1399 | struct net_device *dev; | |
1400 | ||
1401 | dev = dev_get_by_index_rcu(dev_net(skb->dev), ifindex); | |
1402 | if (unlikely(!dev)) | |
1403 | return -EINVAL; | |
1404 | ||
1405 | if (unlikely(!(dev->flags & IFF_UP))) | |
1406 | return -EINVAL; | |
1407 | ||
1408 | skb2 = skb_clone(skb, GFP_ATOMIC); | |
1409 | if (unlikely(!skb2)) | |
1410 | return -ENOMEM; | |
1411 | ||
3896d655 AS |
1412 | if (BPF_IS_REDIRECT_INGRESS(flags)) |
1413 | return dev_forward_skb(dev, skb2); | |
1414 | ||
1415 | skb2->dev = dev; | |
1416 | return dev_queue_xmit(skb2); | |
1417 | } | |
1418 | ||
1419 | const struct bpf_func_proto bpf_clone_redirect_proto = { | |
1420 | .func = bpf_clone_redirect, | |
1421 | .gpl_only = false, | |
1422 | .ret_type = RET_INTEGER, | |
1423 | .arg1_type = ARG_PTR_TO_CTX, | |
1424 | .arg2_type = ARG_ANYTHING, | |
1425 | .arg3_type = ARG_ANYTHING, | |
1426 | }; | |
1427 | ||
8d20aabe DB |
1428 | static u64 bpf_get_cgroup_classid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) |
1429 | { | |
1430 | return task_get_classid((struct sk_buff *) (unsigned long) r1); | |
1431 | } | |
1432 | ||
1433 | static const struct bpf_func_proto bpf_get_cgroup_classid_proto = { | |
1434 | .func = bpf_get_cgroup_classid, | |
1435 | .gpl_only = false, | |
1436 | .ret_type = RET_INTEGER, | |
1437 | .arg1_type = ARG_PTR_TO_CTX, | |
1438 | }; | |
1439 | ||
4e10df9a AS |
1440 | static u64 bpf_skb_vlan_push(u64 r1, u64 r2, u64 vlan_tci, u64 r4, u64 r5) |
1441 | { | |
1442 | struct sk_buff *skb = (struct sk_buff *) (long) r1; | |
1443 | __be16 vlan_proto = (__force __be16) r2; | |
1444 | ||
1445 | if (unlikely(vlan_proto != htons(ETH_P_8021Q) && | |
1446 | vlan_proto != htons(ETH_P_8021AD))) | |
1447 | vlan_proto = htons(ETH_P_8021Q); | |
1448 | ||
1449 | return skb_vlan_push(skb, vlan_proto, vlan_tci); | |
1450 | } | |
1451 | ||
1452 | const struct bpf_func_proto bpf_skb_vlan_push_proto = { | |
1453 | .func = bpf_skb_vlan_push, | |
1454 | .gpl_only = false, | |
1455 | .ret_type = RET_INTEGER, | |
1456 | .arg1_type = ARG_PTR_TO_CTX, | |
1457 | .arg2_type = ARG_ANYTHING, | |
1458 | .arg3_type = ARG_ANYTHING, | |
1459 | }; | |
1460 | ||
1461 | static u64 bpf_skb_vlan_pop(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | |
1462 | { | |
1463 | struct sk_buff *skb = (struct sk_buff *) (long) r1; | |
1464 | ||
1465 | return skb_vlan_pop(skb); | |
1466 | } | |
1467 | ||
1468 | const struct bpf_func_proto bpf_skb_vlan_pop_proto = { | |
1469 | .func = bpf_skb_vlan_pop, | |
1470 | .gpl_only = false, | |
1471 | .ret_type = RET_INTEGER, | |
1472 | .arg1_type = ARG_PTR_TO_CTX, | |
1473 | }; | |
1474 | ||
1475 | bool bpf_helper_changes_skb_data(void *func) | |
1476 | { | |
1477 | if (func == bpf_skb_vlan_push) | |
1478 | return true; | |
1479 | if (func == bpf_skb_vlan_pop) | |
1480 | return true; | |
1481 | return false; | |
1482 | } | |
1483 | ||
d4052c4a DB |
1484 | static const struct bpf_func_proto * |
1485 | sk_filter_func_proto(enum bpf_func_id func_id) | |
89aa0758 AS |
1486 | { |
1487 | switch (func_id) { | |
1488 | case BPF_FUNC_map_lookup_elem: | |
1489 | return &bpf_map_lookup_elem_proto; | |
1490 | case BPF_FUNC_map_update_elem: | |
1491 | return &bpf_map_update_elem_proto; | |
1492 | case BPF_FUNC_map_delete_elem: | |
1493 | return &bpf_map_delete_elem_proto; | |
03e69b50 DB |
1494 | case BPF_FUNC_get_prandom_u32: |
1495 | return &bpf_get_prandom_u32_proto; | |
c04167ce DB |
1496 | case BPF_FUNC_get_smp_processor_id: |
1497 | return &bpf_get_smp_processor_id_proto; | |
04fd61ab AS |
1498 | case BPF_FUNC_tail_call: |
1499 | return &bpf_tail_call_proto; | |
17ca8cbf DB |
1500 | case BPF_FUNC_ktime_get_ns: |
1501 | return &bpf_ktime_get_ns_proto; | |
0756ea3e AS |
1502 | case BPF_FUNC_trace_printk: |
1503 | return bpf_get_trace_printk_proto(); | |
89aa0758 AS |
1504 | default: |
1505 | return NULL; | |
1506 | } | |
1507 | } | |
1508 | ||
608cd71a AS |
1509 | static const struct bpf_func_proto * |
1510 | tc_cls_act_func_proto(enum bpf_func_id func_id) | |
1511 | { | |
1512 | switch (func_id) { | |
1513 | case BPF_FUNC_skb_store_bytes: | |
1514 | return &bpf_skb_store_bytes_proto; | |
91bc4822 AS |
1515 | case BPF_FUNC_l3_csum_replace: |
1516 | return &bpf_l3_csum_replace_proto; | |
1517 | case BPF_FUNC_l4_csum_replace: | |
1518 | return &bpf_l4_csum_replace_proto; | |
3896d655 AS |
1519 | case BPF_FUNC_clone_redirect: |
1520 | return &bpf_clone_redirect_proto; | |
8d20aabe DB |
1521 | case BPF_FUNC_get_cgroup_classid: |
1522 | return &bpf_get_cgroup_classid_proto; | |
4e10df9a AS |
1523 | case BPF_FUNC_skb_vlan_push: |
1524 | return &bpf_skb_vlan_push_proto; | |
1525 | case BPF_FUNC_skb_vlan_pop: | |
1526 | return &bpf_skb_vlan_pop_proto; | |
608cd71a AS |
1527 | default: |
1528 | return sk_filter_func_proto(func_id); | |
1529 | } | |
1530 | } | |
1531 | ||
d691f9e8 | 1532 | static bool __is_valid_access(int off, int size, enum bpf_access_type type) |
89aa0758 | 1533 | { |
9bac3d6d AS |
1534 | /* check bounds */ |
1535 | if (off < 0 || off >= sizeof(struct __sk_buff)) | |
1536 | return false; | |
1537 | ||
1538 | /* disallow misaligned access */ | |
1539 | if (off % size != 0) | |
1540 | return false; | |
1541 | ||
1542 | /* all __sk_buff fields are __u32 */ | |
1543 | if (size != 4) | |
1544 | return false; | |
1545 | ||
1546 | return true; | |
1547 | } | |
1548 | ||
d691f9e8 AS |
1549 | static bool sk_filter_is_valid_access(int off, int size, |
1550 | enum bpf_access_type type) | |
1551 | { | |
1552 | if (type == BPF_WRITE) { | |
1553 | switch (off) { | |
1554 | case offsetof(struct __sk_buff, cb[0]) ... | |
1555 | offsetof(struct __sk_buff, cb[4]): | |
1556 | break; | |
1557 | default: | |
1558 | return false; | |
1559 | } | |
1560 | } | |
1561 | ||
1562 | return __is_valid_access(off, size, type); | |
1563 | } | |
1564 | ||
1565 | static bool tc_cls_act_is_valid_access(int off, int size, | |
1566 | enum bpf_access_type type) | |
1567 | { | |
1568 | if (type == BPF_WRITE) { | |
1569 | switch (off) { | |
1570 | case offsetof(struct __sk_buff, mark): | |
1571 | case offsetof(struct __sk_buff, tc_index): | |
1572 | case offsetof(struct __sk_buff, cb[0]) ... | |
1573 | offsetof(struct __sk_buff, cb[4]): | |
1574 | break; | |
1575 | default: | |
1576 | return false; | |
1577 | } | |
1578 | } | |
1579 | return __is_valid_access(off, size, type); | |
1580 | } | |
1581 | ||
1582 | static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg, | |
1583 | int src_reg, int ctx_off, | |
1584 | struct bpf_insn *insn_buf) | |
9bac3d6d AS |
1585 | { |
1586 | struct bpf_insn *insn = insn_buf; | |
1587 | ||
1588 | switch (ctx_off) { | |
1589 | case offsetof(struct __sk_buff, len): | |
1590 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4); | |
1591 | ||
1592 | *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, | |
1593 | offsetof(struct sk_buff, len)); | |
1594 | break; | |
1595 | ||
0b8c707d DB |
1596 | case offsetof(struct __sk_buff, protocol): |
1597 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2); | |
1598 | ||
1599 | *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg, | |
1600 | offsetof(struct sk_buff, protocol)); | |
1601 | break; | |
1602 | ||
27cd5452 MS |
1603 | case offsetof(struct __sk_buff, vlan_proto): |
1604 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2); | |
1605 | ||
1606 | *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg, | |
1607 | offsetof(struct sk_buff, vlan_proto)); | |
1608 | break; | |
1609 | ||
bcad5718 DB |
1610 | case offsetof(struct __sk_buff, priority): |
1611 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, priority) != 4); | |
1612 | ||
1613 | *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, | |
1614 | offsetof(struct sk_buff, priority)); | |
1615 | break; | |
1616 | ||
37e82c2f AS |
1617 | case offsetof(struct __sk_buff, ingress_ifindex): |
1618 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, skb_iif) != 4); | |
1619 | ||
1620 | *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, | |
1621 | offsetof(struct sk_buff, skb_iif)); | |
1622 | break; | |
1623 | ||
1624 | case offsetof(struct __sk_buff, ifindex): | |
1625 | BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); | |
1626 | ||
1627 | *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)), | |
1628 | dst_reg, src_reg, | |
1629 | offsetof(struct sk_buff, dev)); | |
1630 | *insn++ = BPF_JMP_IMM(BPF_JEQ, dst_reg, 0, 1); | |
1631 | *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, dst_reg, | |
1632 | offsetof(struct net_device, ifindex)); | |
1633 | break; | |
1634 | ||
9bac3d6d | 1635 | case offsetof(struct __sk_buff, mark): |
d691f9e8 AS |
1636 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); |
1637 | ||
1638 | if (type == BPF_WRITE) | |
1639 | *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg, | |
1640 | offsetof(struct sk_buff, mark)); | |
1641 | else | |
1642 | *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, | |
1643 | offsetof(struct sk_buff, mark)); | |
1644 | break; | |
9bac3d6d AS |
1645 | |
1646 | case offsetof(struct __sk_buff, pkt_type): | |
1647 | return convert_skb_access(SKF_AD_PKTTYPE, dst_reg, src_reg, insn); | |
1648 | ||
1649 | case offsetof(struct __sk_buff, queue_mapping): | |
1650 | return convert_skb_access(SKF_AD_QUEUE, dst_reg, src_reg, insn); | |
c2497395 | 1651 | |
c2497395 AS |
1652 | case offsetof(struct __sk_buff, vlan_present): |
1653 | return convert_skb_access(SKF_AD_VLAN_TAG_PRESENT, | |
1654 | dst_reg, src_reg, insn); | |
1655 | ||
1656 | case offsetof(struct __sk_buff, vlan_tci): | |
1657 | return convert_skb_access(SKF_AD_VLAN_TAG, | |
1658 | dst_reg, src_reg, insn); | |
d691f9e8 AS |
1659 | |
1660 | case offsetof(struct __sk_buff, cb[0]) ... | |
1661 | offsetof(struct __sk_buff, cb[4]): | |
1662 | BUILD_BUG_ON(FIELD_SIZEOF(struct qdisc_skb_cb, data) < 20); | |
1663 | ||
1664 | ctx_off -= offsetof(struct __sk_buff, cb[0]); | |
1665 | ctx_off += offsetof(struct sk_buff, cb); | |
1666 | ctx_off += offsetof(struct qdisc_skb_cb, data); | |
1667 | if (type == BPF_WRITE) | |
1668 | *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg, ctx_off); | |
1669 | else | |
1670 | *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, ctx_off); | |
1671 | break; | |
1672 | ||
1673 | case offsetof(struct __sk_buff, tc_index): | |
1674 | #ifdef CONFIG_NET_SCHED | |
1675 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, tc_index) != 2); | |
1676 | ||
1677 | if (type == BPF_WRITE) | |
1678 | *insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg, | |
1679 | offsetof(struct sk_buff, tc_index)); | |
1680 | else | |
1681 | *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg, | |
1682 | offsetof(struct sk_buff, tc_index)); | |
1683 | break; | |
1684 | #else | |
1685 | if (type == BPF_WRITE) | |
1686 | *insn++ = BPF_MOV64_REG(dst_reg, dst_reg); | |
1687 | else | |
1688 | *insn++ = BPF_MOV64_IMM(dst_reg, 0); | |
1689 | break; | |
1690 | #endif | |
9bac3d6d AS |
1691 | } |
1692 | ||
1693 | return insn - insn_buf; | |
89aa0758 AS |
1694 | } |
1695 | ||
d4052c4a DB |
1696 | static const struct bpf_verifier_ops sk_filter_ops = { |
1697 | .get_func_proto = sk_filter_func_proto, | |
1698 | .is_valid_access = sk_filter_is_valid_access, | |
d691f9e8 | 1699 | .convert_ctx_access = bpf_net_convert_ctx_access, |
89aa0758 AS |
1700 | }; |
1701 | ||
608cd71a AS |
1702 | static const struct bpf_verifier_ops tc_cls_act_ops = { |
1703 | .get_func_proto = tc_cls_act_func_proto, | |
d691f9e8 AS |
1704 | .is_valid_access = tc_cls_act_is_valid_access, |
1705 | .convert_ctx_access = bpf_net_convert_ctx_access, | |
608cd71a AS |
1706 | }; |
1707 | ||
d4052c4a DB |
1708 | static struct bpf_prog_type_list sk_filter_type __read_mostly = { |
1709 | .ops = &sk_filter_ops, | |
89aa0758 AS |
1710 | .type = BPF_PROG_TYPE_SOCKET_FILTER, |
1711 | }; | |
1712 | ||
96be4325 | 1713 | static struct bpf_prog_type_list sched_cls_type __read_mostly = { |
608cd71a | 1714 | .ops = &tc_cls_act_ops, |
96be4325 DB |
1715 | .type = BPF_PROG_TYPE_SCHED_CLS, |
1716 | }; | |
1717 | ||
94caee8c | 1718 | static struct bpf_prog_type_list sched_act_type __read_mostly = { |
608cd71a | 1719 | .ops = &tc_cls_act_ops, |
94caee8c DB |
1720 | .type = BPF_PROG_TYPE_SCHED_ACT, |
1721 | }; | |
1722 | ||
d4052c4a | 1723 | static int __init register_sk_filter_ops(void) |
89aa0758 | 1724 | { |
d4052c4a | 1725 | bpf_register_prog_type(&sk_filter_type); |
96be4325 | 1726 | bpf_register_prog_type(&sched_cls_type); |
94caee8c | 1727 | bpf_register_prog_type(&sched_act_type); |
96be4325 | 1728 | |
89aa0758 AS |
1729 | return 0; |
1730 | } | |
d4052c4a DB |
1731 | late_initcall(register_sk_filter_ops); |
1732 | ||
55b33325 PE |
1733 | int sk_detach_filter(struct sock *sk) |
1734 | { | |
1735 | int ret = -ENOENT; | |
1736 | struct sk_filter *filter; | |
1737 | ||
d59577b6 VB |
1738 | if (sock_flag(sk, SOCK_FILTER_LOCKED)) |
1739 | return -EPERM; | |
1740 | ||
f91ff5b9 ED |
1741 | filter = rcu_dereference_protected(sk->sk_filter, |
1742 | sock_owned_by_user(sk)); | |
55b33325 | 1743 | if (filter) { |
a9b3cd7f | 1744 | RCU_INIT_POINTER(sk->sk_filter, NULL); |
46bcf14f | 1745 | sk_filter_uncharge(sk, filter); |
55b33325 PE |
1746 | ret = 0; |
1747 | } | |
a3ea269b | 1748 | |
55b33325 PE |
1749 | return ret; |
1750 | } | |
5ff3f073 | 1751 | EXPORT_SYMBOL_GPL(sk_detach_filter); |
a8fc9277 | 1752 | |
a3ea269b DB |
1753 | int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf, |
1754 | unsigned int len) | |
a8fc9277 | 1755 | { |
a3ea269b | 1756 | struct sock_fprog_kern *fprog; |
a8fc9277 | 1757 | struct sk_filter *filter; |
a3ea269b | 1758 | int ret = 0; |
a8fc9277 PE |
1759 | |
1760 | lock_sock(sk); | |
1761 | filter = rcu_dereference_protected(sk->sk_filter, | |
a3ea269b | 1762 | sock_owned_by_user(sk)); |
a8fc9277 PE |
1763 | if (!filter) |
1764 | goto out; | |
a3ea269b DB |
1765 | |
1766 | /* We're copying the filter that has been originally attached, | |
1767 | * so no conversion/decode needed anymore. | |
1768 | */ | |
7ae457c1 | 1769 | fprog = filter->prog->orig_prog; |
a3ea269b DB |
1770 | |
1771 | ret = fprog->len; | |
a8fc9277 | 1772 | if (!len) |
a3ea269b | 1773 | /* User space only enquires number of filter blocks. */ |
a8fc9277 | 1774 | goto out; |
a3ea269b | 1775 | |
a8fc9277 | 1776 | ret = -EINVAL; |
a3ea269b | 1777 | if (len < fprog->len) |
a8fc9277 PE |
1778 | goto out; |
1779 | ||
1780 | ret = -EFAULT; | |
009937e7 | 1781 | if (copy_to_user(ubuf, fprog->filter, bpf_classic_proglen(fprog))) |
a3ea269b | 1782 | goto out; |
a8fc9277 | 1783 | |
a3ea269b DB |
1784 | /* Instead of bytes, the API requests to return the number |
1785 | * of filter blocks. | |
1786 | */ | |
1787 | ret = fprog->len; | |
a8fc9277 PE |
1788 | out: |
1789 | release_sock(sk); | |
1790 | return ret; | |
1791 | } |