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