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