2 * Linux Socket Filter - Kernel level socket filtering
4 * Based on the design of the Berkeley Packet Filter. The new
5 * internal format has been designed by PLUMgrid:
7 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
11 * Jay Schulist <jschlst@samba.org>
12 * Alexei Starovoitov <ast@plumgrid.com>
13 * Daniel Borkmann <dborkman@redhat.com>
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.
20 * Andi Kleen - Fix a few bad bugs and races.
21 * Kris Katterjohn - Added many additional checks in sk_chk_filter()
24 #include <linux/module.h>
25 #include <linux/types.h>
27 #include <linux/fcntl.h>
28 #include <linux/socket.h>
30 #include <linux/inet.h>
31 #include <linux/netdevice.h>
32 #include <linux/if_packet.h>
33 #include <linux/gfp.h>
35 #include <net/protocol.h>
36 #include <net/netlink.h>
37 #include <linux/skbuff.h>
39 #include <linux/errno.h>
40 #include <linux/timer.h>
41 #include <asm/uaccess.h>
42 #include <asm/unaligned.h>
43 #include <linux/filter.h>
44 #include <linux/ratelimit.h>
45 #include <linux/seccomp.h>
46 #include <linux/if_vlan.h>
49 #define BPF_R0 regs[BPF_REG_0]
50 #define BPF_R1 regs[BPF_REG_1]
51 #define BPF_R2 regs[BPF_REG_2]
52 #define BPF_R3 regs[BPF_REG_3]
53 #define BPF_R4 regs[BPF_REG_4]
54 #define BPF_R5 regs[BPF_REG_5]
55 #define BPF_R6 regs[BPF_REG_6]
56 #define BPF_R7 regs[BPF_REG_7]
57 #define BPF_R8 regs[BPF_REG_8]
58 #define BPF_R9 regs[BPF_REG_9]
59 #define BPF_R10 regs[BPF_REG_10]
62 #define A regs[insn->a_reg]
63 #define X regs[insn->x_reg]
64 #define FP regs[BPF_REG_FP]
65 #define ARG1 regs[BPF_REG_ARG1]
66 #define CTX regs[BPF_REG_CTX]
69 /* No hurry in this branch
71 * Exported for the bpf jit load helper.
73 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
78 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
79 else if (k >= SKF_LL_OFF)
80 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
81 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
87 static inline void *load_pointer(const struct sk_buff *skb, int k,
88 unsigned int size, void *buffer)
91 return skb_header_pointer(skb, k, size, buffer);
93 return bpf_internal_load_pointer_neg_helper(skb, k, size);
97 * sk_filter - run a packet through a socket filter
98 * @sk: sock associated with &sk_buff
99 * @skb: buffer to filter
101 * Run the filter code and then cut skb->data to correct size returned by
102 * sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller
103 * than pkt_len we keep whole skb->data. This is the socket level
104 * wrapper to sk_run_filter. It returns 0 if the packet should
105 * be accepted or -EPERM if the packet should be tossed.
108 int sk_filter(struct sock *sk, struct sk_buff *skb)
111 struct sk_filter *filter;
114 * If the skb was allocated from pfmemalloc reserves, only
115 * allow SOCK_MEMALLOC sockets to use it as this socket is
116 * helping free memory
118 if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
121 err = security_sock_rcv_skb(sk, skb);
126 filter = rcu_dereference(sk->sk_filter);
128 unsigned int pkt_len = SK_RUN_FILTER(filter, skb);
130 err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
136 EXPORT_SYMBOL(sk_filter);
138 /* Base function for offset calculation. Needs to go into .text section,
139 * therefore keeping it non-static as well; will also be used by JITs
140 * anyway later on, so do not let the compiler omit it.
142 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
148 * __sk_run_filter - run a filter on a given context
149 * @ctx: buffer to run the filter on
150 * @insn: filter to apply
152 * Decode and apply filter instructions to the skb->data. Return length to
153 * keep, 0 for none. @ctx is the data we are operating on, @insn is the
154 * array of filter instructions.
156 static unsigned int __sk_run_filter(void *ctx, const struct sock_filter_int *insn)
158 u64 stack[MAX_BPF_STACK / sizeof(u64)];
159 u64 regs[MAX_BPF_REG], tmp;
160 static const void *jumptable[256] = {
161 [0 ... 255] = &&default_label,
162 /* Now overwrite non-defaults ... */
163 /* 32 bit ALU operations */
164 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
165 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
166 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
167 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
168 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
169 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
170 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X,
171 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K,
172 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
173 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
174 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
175 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
176 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
177 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
178 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
179 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
180 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
181 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
182 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
183 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
184 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
185 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
186 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
187 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
188 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
189 /* 64 bit ALU operations */
190 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
191 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
192 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
193 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
194 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
195 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
196 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
197 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
198 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
199 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
200 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
201 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
202 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
203 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
204 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
205 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
206 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
207 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
208 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
209 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
210 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
211 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
212 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
213 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
214 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
215 /* Call instruction */
216 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
218 [BPF_JMP | BPF_JA] = &&JMP_JA,
219 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
220 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
221 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
222 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
223 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
224 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
225 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
226 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
227 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
228 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
229 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
230 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
231 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
232 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
234 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
235 /* Store instructions */
236 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
237 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
238 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
239 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
240 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
241 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
242 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
243 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
244 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
245 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
246 /* Load instructions */
247 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
248 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
249 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
250 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
251 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
252 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
253 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
254 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
255 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
256 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
261 #define CONT ({ insn++; goto select_insn; })
262 #define CONT_JMP ({ insn++; goto select_insn; })
264 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
265 ARG1 = (u64) (unsigned long) ctx;
267 /* Register for user BPF programs need to be reset first. */
272 goto *jumptable[insn->code];
275 #define ALU(OPCODE, OP) \
276 ALU64_##OPCODE##_X: \
280 A = (u32) A OP (u32) X; \
282 ALU64_##OPCODE##_K: \
286 A = (u32) A OP (u32) K; \
323 if (unlikely(X == 0))
329 if (unlikely(X == 0))
332 A = do_div(tmp, (u32) X);
340 A = do_div(tmp, (u32) K);
343 if (unlikely(X == 0))
348 if (unlikely(X == 0))
351 do_div(tmp, (u32) X);
359 do_div(tmp, (u32) K);
365 A = (__force u16) cpu_to_be16(A);
368 A = (__force u32) cpu_to_be32(A);
371 A = (__force u64) cpu_to_be64(A);
378 A = (__force u16) cpu_to_le16(A);
381 A = (__force u32) cpu_to_le32(A);
384 A = (__force u64) cpu_to_le64(A);
391 /* Function call scratches BPF_R1-BPF_R5 registers,
392 * preserves BPF_R6-BPF_R9, and stores return value
395 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
452 if (((s64) A) > ((s64) X)) {
458 if (((s64) A) > ((s64) K)) {
464 if (((s64) A) >= ((s64) X)) {
470 if (((s64) A) >= ((s64) K)) {
490 /* STX and ST and LDX*/
491 #define LDST(SIZEOP, SIZE) \
493 *(SIZE *)(unsigned long) (A + insn->off) = X; \
496 *(SIZE *)(unsigned long) (A + insn->off) = K; \
499 A = *(SIZE *)(unsigned long) (X + insn->off); \
507 STX_XADD_W: /* lock xadd *(u32 *)(A + insn->off) += X */
508 atomic_add((u32) X, (atomic_t *)(unsigned long)
511 STX_XADD_DW: /* lock xadd *(u64 *)(A + insn->off) += X */
512 atomic64_add((u64) X, (atomic64_t *)(unsigned long)
515 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + K)) */
518 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
519 * only appearing in the programs where ctx ==
520 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
521 * == BPF_R6, sk_convert_filter() saves it in BPF_R6,
522 * internal BPF verifier will check that BPF_R6 ==
525 * BPF_ABS and BPF_IND are wrappers of function calls,
526 * so they scratch BPF_R1-BPF_R5 registers, preserve
527 * BPF_R6-BPF_R9, and store return value into BPF_R0.
534 * K == 32-bit immediate
537 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
540 ptr = load_pointer((struct sk_buff *) ctx, off, 4, &tmp);
541 if (likely(ptr != NULL)) {
542 BPF_R0 = get_unaligned_be32(ptr);
547 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + K)) */
550 ptr = load_pointer((struct sk_buff *) ctx, off, 2, &tmp);
551 if (likely(ptr != NULL)) {
552 BPF_R0 = get_unaligned_be16(ptr);
557 LD_ABS_B: /* BPF_R0 = *(u8 *) (ctx + K) */
560 ptr = load_pointer((struct sk_buff *) ctx, off, 1, &tmp);
561 if (likely(ptr != NULL)) {
567 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + X + K)) */
570 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + X + K)) */
573 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + X + K) */
578 /* If we ever reach this, we have a bug somewhere. */
579 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
583 /* Helper to find the offset of pkt_type in sk_buff structure. We want
584 * to make sure its still a 3bit field starting at a byte boundary;
585 * taken from arch/x86/net/bpf_jit_comp.c.
587 #define PKT_TYPE_MAX 7
588 static unsigned int pkt_type_offset(void)
590 struct sk_buff skb_probe = { .pkt_type = ~0, };
591 u8 *ct = (u8 *) &skb_probe;
594 for (off = 0; off < sizeof(struct sk_buff); off++) {
595 if (ct[off] == PKT_TYPE_MAX)
599 pr_err_once("Please fix %s, as pkt_type couldn't be found!\n", __func__);
603 static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
605 return __skb_get_poff((struct sk_buff *)(unsigned long) ctx);
608 static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
610 struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
613 if (skb_is_nonlinear(skb))
616 if (skb->len < sizeof(struct nlattr))
619 if (a > skb->len - sizeof(struct nlattr))
622 nla = nla_find((struct nlattr *) &skb->data[a], skb->len - a, x);
624 return (void *) nla - (void *) skb->data;
629 static u64 __skb_get_nlattr_nest(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
631 struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
634 if (skb_is_nonlinear(skb))
637 if (skb->len < sizeof(struct nlattr))
640 if (a > skb->len - sizeof(struct nlattr))
643 nla = (struct nlattr *) &skb->data[a];
644 if (nla->nla_len > skb->len - a)
647 nla = nla_find_nested(nla, x);
649 return (void *) nla - (void *) skb->data;
654 static u64 __get_raw_cpu_id(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
656 return raw_smp_processor_id();
659 /* note that this only generates 32-bit random numbers */
660 static u64 __get_random_u32(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
662 return prandom_u32();
665 static bool convert_bpf_extensions(struct sock_filter *fp,
666 struct sock_filter_int **insnp)
668 struct sock_filter_int *insn = *insnp;
671 case SKF_AD_OFF + SKF_AD_PROTOCOL:
672 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
674 /* A = *(u16 *) (ctx + offsetof(protocol)) */
675 *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
676 offsetof(struct sk_buff, protocol));
677 /* A = ntohs(A) [emitting a nop or swap16] */
678 *insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
681 case SKF_AD_OFF + SKF_AD_PKTTYPE:
682 *insn = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
687 *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, PKT_TYPE_MAX);
690 case SKF_AD_OFF + SKF_AD_IFINDEX:
691 case SKF_AD_OFF + SKF_AD_HATYPE:
692 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
693 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
694 BUILD_BUG_ON(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)) < 0);
696 *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)),
697 BPF_REG_TMP, BPF_REG_CTX,
698 offsetof(struct sk_buff, dev));
699 /* if (tmp != 0) goto pc + 1 */
700 *insn++ = BPF_JMP_IMM(BPF_JNE, BPF_REG_TMP, 0, 1);
701 *insn++ = BPF_EXIT_INSN();
702 if (fp->k == SKF_AD_OFF + SKF_AD_IFINDEX)
703 *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_TMP,
704 offsetof(struct net_device, ifindex));
706 *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_TMP,
707 offsetof(struct net_device, type));
710 case SKF_AD_OFF + SKF_AD_MARK:
711 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
713 *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX,
714 offsetof(struct sk_buff, mark));
717 case SKF_AD_OFF + SKF_AD_RXHASH:
718 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
720 *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX,
721 offsetof(struct sk_buff, hash));
724 case SKF_AD_OFF + SKF_AD_QUEUE:
725 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
727 *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
728 offsetof(struct sk_buff, queue_mapping));
731 case SKF_AD_OFF + SKF_AD_VLAN_TAG:
732 case SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT:
733 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
734 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
736 /* A = *(u16 *) (ctx + offsetof(vlan_tci)) */
737 *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
738 offsetof(struct sk_buff, vlan_tci));
739 if (fp->k == SKF_AD_OFF + SKF_AD_VLAN_TAG) {
740 *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A,
744 *insn++ = BPF_ALU32_IMM(BPF_RSH, BPF_REG_A, 12);
746 *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 1);
750 case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
751 case SKF_AD_OFF + SKF_AD_NLATTR:
752 case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
753 case SKF_AD_OFF + SKF_AD_CPU:
754 case SKF_AD_OFF + SKF_AD_RANDOM:
756 *insn++ = BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_CTX);
758 *insn++ = BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_A);
760 *insn++ = BPF_MOV64_REG(BPF_REG_ARG3, BPF_REG_X);
761 /* Emit call(ctx, arg2=A, arg3=X) */
763 case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
764 *insn = BPF_EMIT_CALL(__skb_get_pay_offset);
766 case SKF_AD_OFF + SKF_AD_NLATTR:
767 *insn = BPF_EMIT_CALL(__skb_get_nlattr);
769 case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
770 *insn = BPF_EMIT_CALL(__skb_get_nlattr_nest);
772 case SKF_AD_OFF + SKF_AD_CPU:
773 *insn = BPF_EMIT_CALL(__get_raw_cpu_id);
775 case SKF_AD_OFF + SKF_AD_RANDOM:
776 *insn = BPF_EMIT_CALL(__get_random_u32);
781 case SKF_AD_OFF + SKF_AD_ALU_XOR_X:
783 *insn = BPF_ALU32_REG(BPF_XOR, BPF_REG_A, BPF_REG_X);
787 /* This is just a dummy call to avoid letting the compiler
788 * evict __bpf_call_base() as an optimization. Placed here
789 * where no-one bothers.
791 BUG_ON(__bpf_call_base(0, 0, 0, 0, 0) != 0);
800 * sk_convert_filter - convert filter program
801 * @prog: the user passed filter program
802 * @len: the length of the user passed filter program
803 * @new_prog: buffer where converted program will be stored
804 * @new_len: pointer to store length of converted program
806 * Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style.
807 * Conversion workflow:
809 * 1) First pass for calculating the new program length:
810 * sk_convert_filter(old_prog, old_len, NULL, &new_len)
812 * 2) 2nd pass to remap in two passes: 1st pass finds new
813 * jump offsets, 2nd pass remapping:
814 * new_prog = kmalloc(sizeof(struct sock_filter_int) * new_len);
815 * sk_convert_filter(old_prog, old_len, new_prog, &new_len);
817 * User BPF's register A is mapped to our BPF register 6, user BPF
818 * register X is mapped to BPF register 7; frame pointer is always
819 * register 10; Context 'void *ctx' is stored in register 1, that is,
820 * for socket filters: ctx == 'struct sk_buff *', for seccomp:
821 * ctx == 'struct seccomp_data *'.
823 int sk_convert_filter(struct sock_filter *prog, int len,
824 struct sock_filter_int *new_prog, int *new_len)
826 int new_flen = 0, pass = 0, target, i;
827 struct sock_filter_int *new_insn;
828 struct sock_filter *fp;
832 BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK);
833 BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
835 if (len <= 0 || len >= BPF_MAXINSNS)
839 addrs = kzalloc(len * sizeof(*addrs), GFP_KERNEL);
849 *new_insn = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1);
852 for (i = 0; i < len; fp++, i++) {
853 struct sock_filter_int tmp_insns[6] = { };
854 struct sock_filter_int *insn = tmp_insns;
857 addrs[i] = new_insn - new_prog;
860 /* All arithmetic insns and skb loads map as-is. */
861 case BPF_ALU | BPF_ADD | BPF_X:
862 case BPF_ALU | BPF_ADD | BPF_K:
863 case BPF_ALU | BPF_SUB | BPF_X:
864 case BPF_ALU | BPF_SUB | BPF_K:
865 case BPF_ALU | BPF_AND | BPF_X:
866 case BPF_ALU | BPF_AND | BPF_K:
867 case BPF_ALU | BPF_OR | BPF_X:
868 case BPF_ALU | BPF_OR | BPF_K:
869 case BPF_ALU | BPF_LSH | BPF_X:
870 case BPF_ALU | BPF_LSH | BPF_K:
871 case BPF_ALU | BPF_RSH | BPF_X:
872 case BPF_ALU | BPF_RSH | BPF_K:
873 case BPF_ALU | BPF_XOR | BPF_X:
874 case BPF_ALU | BPF_XOR | BPF_K:
875 case BPF_ALU | BPF_MUL | BPF_X:
876 case BPF_ALU | BPF_MUL | BPF_K:
877 case BPF_ALU | BPF_DIV | BPF_X:
878 case BPF_ALU | BPF_DIV | BPF_K:
879 case BPF_ALU | BPF_MOD | BPF_X:
880 case BPF_ALU | BPF_MOD | BPF_K:
881 case BPF_ALU | BPF_NEG:
882 case BPF_LD | BPF_ABS | BPF_W:
883 case BPF_LD | BPF_ABS | BPF_H:
884 case BPF_LD | BPF_ABS | BPF_B:
885 case BPF_LD | BPF_IND | BPF_W:
886 case BPF_LD | BPF_IND | BPF_H:
887 case BPF_LD | BPF_IND | BPF_B:
888 /* Check for overloaded BPF extension and
889 * directly convert it if found, otherwise
890 * just move on with mapping.
892 if (BPF_CLASS(fp->code) == BPF_LD &&
893 BPF_MODE(fp->code) == BPF_ABS &&
894 convert_bpf_extensions(fp, &insn))
897 *insn = BPF_RAW_INSN(fp->code, BPF_REG_A, BPF_REG_X, 0, fp->k);
900 /* Jump transformation cannot use BPF block macros
901 * everywhere as offset calculation and target updates
902 * require a bit more work than the rest, i.e. jump
903 * opcodes map as-is, but offsets need adjustment.
906 #define BPF_EMIT_JMP \
908 if (target >= len || target < 0) \
910 insn->off = addrs ? addrs[target] - addrs[i] - 1 : 0; \
911 /* Adjust pc relative offset for 2nd or 3rd insn. */ \
912 insn->off -= insn - tmp_insns; \
915 case BPF_JMP | BPF_JA:
916 target = i + fp->k + 1;
917 insn->code = fp->code;
921 case BPF_JMP | BPF_JEQ | BPF_K:
922 case BPF_JMP | BPF_JEQ | BPF_X:
923 case BPF_JMP | BPF_JSET | BPF_K:
924 case BPF_JMP | BPF_JSET | BPF_X:
925 case BPF_JMP | BPF_JGT | BPF_K:
926 case BPF_JMP | BPF_JGT | BPF_X:
927 case BPF_JMP | BPF_JGE | BPF_K:
928 case BPF_JMP | BPF_JGE | BPF_X:
929 if (BPF_SRC(fp->code) == BPF_K && (int) fp->k < 0) {
930 /* BPF immediates are signed, zero extend
931 * immediate into tmp register and use it
934 *insn++ = BPF_MOV32_IMM(BPF_REG_TMP, fp->k);
936 insn->a_reg = BPF_REG_A;
937 insn->x_reg = BPF_REG_TMP;
940 insn->a_reg = BPF_REG_A;
941 insn->x_reg = BPF_REG_X;
943 bpf_src = BPF_SRC(fp->code);
946 /* Common case where 'jump_false' is next insn. */
948 insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
949 target = i + fp->jt + 1;
954 /* Convert JEQ into JNE when 'jump_true' is next insn. */
955 if (fp->jt == 0 && BPF_OP(fp->code) == BPF_JEQ) {
956 insn->code = BPF_JMP | BPF_JNE | bpf_src;
957 target = i + fp->jf + 1;
962 /* Other jumps are mapped into two insns: Jxx and JA. */
963 target = i + fp->jt + 1;
964 insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
968 insn->code = BPF_JMP | BPF_JA;
969 target = i + fp->jf + 1;
973 /* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */
974 case BPF_LDX | BPF_MSH | BPF_B:
976 *insn++ = BPF_MOV64_REG(BPF_REG_TMP, BPF_REG_A);
977 /* A = BPF_R0 = *(u8 *) (skb->data + K) */
978 *insn++ = BPF_LD_ABS(BPF_B, fp->k);
980 *insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 0xf);
982 *insn++ = BPF_ALU32_IMM(BPF_LSH, BPF_REG_A, 2);
984 *insn++ = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
986 *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_TMP);
989 /* RET_K, RET_A are remaped into 2 insns. */
990 case BPF_RET | BPF_A:
991 case BPF_RET | BPF_K:
992 *insn++ = BPF_MOV32_RAW(BPF_RVAL(fp->code) == BPF_K ?
993 BPF_K : BPF_X, BPF_REG_0,
995 *insn = BPF_EXIT_INSN();
998 /* Store to stack. */
1001 *insn = BPF_STX_MEM(BPF_W, BPF_REG_FP, BPF_CLASS(fp->code) ==
1002 BPF_ST ? BPF_REG_A : BPF_REG_X,
1003 -(BPF_MEMWORDS - fp->k) * 4);
1006 /* Load from stack. */
1007 case BPF_LD | BPF_MEM:
1008 case BPF_LDX | BPF_MEM:
1009 *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
1010 BPF_REG_A : BPF_REG_X, BPF_REG_FP,
1011 -(BPF_MEMWORDS - fp->k) * 4);
1014 /* A = K or X = K */
1015 case BPF_LD | BPF_IMM:
1016 case BPF_LDX | BPF_IMM:
1017 *insn = BPF_MOV32_IMM(BPF_CLASS(fp->code) == BPF_LD ?
1018 BPF_REG_A : BPF_REG_X, fp->k);
1022 case BPF_MISC | BPF_TAX:
1023 *insn = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
1027 case BPF_MISC | BPF_TXA:
1028 *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_X);
1031 /* A = skb->len or X = skb->len */
1032 case BPF_LD | BPF_W | BPF_LEN:
1033 case BPF_LDX | BPF_W | BPF_LEN:
1034 *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
1035 BPF_REG_A : BPF_REG_X, BPF_REG_CTX,
1036 offsetof(struct sk_buff, len));
1039 /* Access seccomp_data fields. */
1040 case BPF_LDX | BPF_ABS | BPF_W:
1041 /* A = *(u32 *) (ctx + K) */
1042 *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, fp->k);
1045 /* Unkown instruction. */
1052 memcpy(new_insn, tmp_insns,
1053 sizeof(*insn) * (insn - tmp_insns));
1054 new_insn += insn - tmp_insns;
1058 /* Only calculating new length. */
1059 *new_len = new_insn - new_prog;
1064 if (new_flen != new_insn - new_prog) {
1065 new_flen = new_insn - new_prog;
1072 BUG_ON(*new_len != new_flen);
1081 * A BPF program is able to use 16 cells of memory to store intermediate
1082 * values (check u32 mem[BPF_MEMWORDS] in sk_run_filter()).
1084 * As we dont want to clear mem[] array for each packet going through
1085 * sk_run_filter(), we check that filter loaded by user never try to read
1086 * a cell if not previously written, and we check all branches to be sure
1087 * a malicious user doesn't try to abuse us.
1089 static int check_load_and_stores(struct sock_filter *filter, int flen)
1091 u16 *masks, memvalid = 0; /* One bit per cell, 16 cells */
1094 BUILD_BUG_ON(BPF_MEMWORDS > 16);
1096 masks = kmalloc(flen * sizeof(*masks), GFP_KERNEL);
1100 memset(masks, 0xff, flen * sizeof(*masks));
1102 for (pc = 0; pc < flen; pc++) {
1103 memvalid &= masks[pc];
1105 switch (filter[pc].code) {
1108 memvalid |= (1 << filter[pc].k);
1110 case BPF_LD | BPF_MEM:
1111 case BPF_LDX | BPF_MEM:
1112 if (!(memvalid & (1 << filter[pc].k))) {
1117 case BPF_JMP | BPF_JA:
1118 /* A jump must set masks on target */
1119 masks[pc + 1 + filter[pc].k] &= memvalid;
1122 case BPF_JMP | BPF_JEQ | BPF_K:
1123 case BPF_JMP | BPF_JEQ | BPF_X:
1124 case BPF_JMP | BPF_JGE | BPF_K:
1125 case BPF_JMP | BPF_JGE | BPF_X:
1126 case BPF_JMP | BPF_JGT | BPF_K:
1127 case BPF_JMP | BPF_JGT | BPF_X:
1128 case BPF_JMP | BPF_JSET | BPF_K:
1129 case BPF_JMP | BPF_JSET | BPF_X:
1130 /* A jump must set masks on targets */
1131 masks[pc + 1 + filter[pc].jt] &= memvalid;
1132 masks[pc + 1 + filter[pc].jf] &= memvalid;
1142 static bool chk_code_allowed(u16 code_to_probe)
1144 static const bool codes[] = {
1145 /* 32 bit ALU operations */
1146 [BPF_ALU | BPF_ADD | BPF_K] = true,
1147 [BPF_ALU | BPF_ADD | BPF_X] = true,
1148 [BPF_ALU | BPF_SUB | BPF_K] = true,
1149 [BPF_ALU | BPF_SUB | BPF_X] = true,
1150 [BPF_ALU | BPF_MUL | BPF_K] = true,
1151 [BPF_ALU | BPF_MUL | BPF_X] = true,
1152 [BPF_ALU | BPF_DIV | BPF_K] = true,
1153 [BPF_ALU | BPF_DIV | BPF_X] = true,
1154 [BPF_ALU | BPF_MOD | BPF_K] = true,
1155 [BPF_ALU | BPF_MOD | BPF_X] = true,
1156 [BPF_ALU | BPF_AND | BPF_K] = true,
1157 [BPF_ALU | BPF_AND | BPF_X] = true,
1158 [BPF_ALU | BPF_OR | BPF_K] = true,
1159 [BPF_ALU | BPF_OR | BPF_X] = true,
1160 [BPF_ALU | BPF_XOR | BPF_K] = true,
1161 [BPF_ALU | BPF_XOR | BPF_X] = true,
1162 [BPF_ALU | BPF_LSH | BPF_K] = true,
1163 [BPF_ALU | BPF_LSH | BPF_X] = true,
1164 [BPF_ALU | BPF_RSH | BPF_K] = true,
1165 [BPF_ALU | BPF_RSH | BPF_X] = true,
1166 [BPF_ALU | BPF_NEG] = true,
1167 /* Load instructions */
1168 [BPF_LD | BPF_W | BPF_ABS] = true,
1169 [BPF_LD | BPF_H | BPF_ABS] = true,
1170 [BPF_LD | BPF_B | BPF_ABS] = true,
1171 [BPF_LD | BPF_W | BPF_LEN] = true,
1172 [BPF_LD | BPF_W | BPF_IND] = true,
1173 [BPF_LD | BPF_H | BPF_IND] = true,
1174 [BPF_LD | BPF_B | BPF_IND] = true,
1175 [BPF_LD | BPF_IMM] = true,
1176 [BPF_LD | BPF_MEM] = true,
1177 [BPF_LDX | BPF_W | BPF_LEN] = true,
1178 [BPF_LDX | BPF_B | BPF_MSH] = true,
1179 [BPF_LDX | BPF_IMM] = true,
1180 [BPF_LDX | BPF_MEM] = true,
1181 /* Store instructions */
1184 /* Misc instructions */
1185 [BPF_MISC | BPF_TAX] = true,
1186 [BPF_MISC | BPF_TXA] = true,
1187 /* Return instructions */
1188 [BPF_RET | BPF_K] = true,
1189 [BPF_RET | BPF_A] = true,
1190 /* Jump instructions */
1191 [BPF_JMP | BPF_JA] = true,
1192 [BPF_JMP | BPF_JEQ | BPF_K] = true,
1193 [BPF_JMP | BPF_JEQ | BPF_X] = true,
1194 [BPF_JMP | BPF_JGE | BPF_K] = true,
1195 [BPF_JMP | BPF_JGE | BPF_X] = true,
1196 [BPF_JMP | BPF_JGT | BPF_K] = true,
1197 [BPF_JMP | BPF_JGT | BPF_X] = true,
1198 [BPF_JMP | BPF_JSET | BPF_K] = true,
1199 [BPF_JMP | BPF_JSET | BPF_X] = true,
1202 if (code_to_probe >= ARRAY_SIZE(codes))
1205 return codes[code_to_probe];
1209 * sk_chk_filter - verify socket filter code
1210 * @filter: filter to verify
1211 * @flen: length of filter
1213 * Check the user's filter code. If we let some ugly
1214 * filter code slip through kaboom! The filter must contain
1215 * no references or jumps that are out of range, no illegal
1216 * instructions, and must end with a RET instruction.
1218 * All jumps are forward as they are not signed.
1220 * Returns 0 if the rule set is legal or -EINVAL if not.
1222 int sk_chk_filter(struct sock_filter *filter, unsigned int flen)
1227 if (flen == 0 || flen > BPF_MAXINSNS)
1230 /* Check the filter code now */
1231 for (pc = 0; pc < flen; pc++) {
1232 struct sock_filter *ftest = &filter[pc];
1234 /* May we actually operate on this code? */
1235 if (!chk_code_allowed(ftest->code))
1238 /* Some instructions need special checks */
1239 switch (ftest->code) {
1240 case BPF_ALU | BPF_DIV | BPF_K:
1241 case BPF_ALU | BPF_MOD | BPF_K:
1242 /* Check for division by zero */
1246 case BPF_LD | BPF_MEM:
1247 case BPF_LDX | BPF_MEM:
1250 /* Check for invalid memory addresses */
1251 if (ftest->k >= BPF_MEMWORDS)
1254 case BPF_JMP | BPF_JA:
1255 /* Note, the large ftest->k might cause loops.
1256 * Compare this with conditional jumps below,
1257 * where offsets are limited. --ANK (981016)
1259 if (ftest->k >= (unsigned int)(flen - pc - 1))
1262 case BPF_JMP | BPF_JEQ | BPF_K:
1263 case BPF_JMP | BPF_JEQ | BPF_X:
1264 case BPF_JMP | BPF_JGE | BPF_K:
1265 case BPF_JMP | BPF_JGE | BPF_X:
1266 case BPF_JMP | BPF_JGT | BPF_K:
1267 case BPF_JMP | BPF_JGT | BPF_X:
1268 case BPF_JMP | BPF_JSET | BPF_K:
1269 case BPF_JMP | BPF_JSET | BPF_X:
1270 /* Both conditionals must be safe */
1271 if (pc + ftest->jt + 1 >= flen ||
1272 pc + ftest->jf + 1 >= flen)
1275 case BPF_LD | BPF_W | BPF_ABS:
1276 case BPF_LD | BPF_H | BPF_ABS:
1277 case BPF_LD | BPF_B | BPF_ABS:
1279 if (bpf_anc_helper(ftest) & BPF_ANC)
1281 /* Ancillary operation unknown or unsupported */
1282 if (anc_found == false && ftest->k >= SKF_AD_OFF)
1287 /* Last instruction must be a RET code */
1288 switch (filter[flen - 1].code) {
1289 case BPF_RET | BPF_K:
1290 case BPF_RET | BPF_A:
1291 return check_load_and_stores(filter, flen);
1296 EXPORT_SYMBOL(sk_chk_filter);
1298 static int sk_store_orig_filter(struct sk_filter *fp,
1299 const struct sock_fprog *fprog)
1301 unsigned int fsize = sk_filter_proglen(fprog);
1302 struct sock_fprog_kern *fkprog;
1304 fp->orig_prog = kmalloc(sizeof(*fkprog), GFP_KERNEL);
1308 fkprog = fp->orig_prog;
1309 fkprog->len = fprog->len;
1310 fkprog->filter = kmemdup(fp->insns, fsize, GFP_KERNEL);
1311 if (!fkprog->filter) {
1312 kfree(fp->orig_prog);
1319 static void sk_release_orig_filter(struct sk_filter *fp)
1321 struct sock_fprog_kern *fprog = fp->orig_prog;
1324 kfree(fprog->filter);
1330 * sk_filter_release_rcu - Release a socket filter by rcu_head
1331 * @rcu: rcu_head that contains the sk_filter to free
1333 static void sk_filter_release_rcu(struct rcu_head *rcu)
1335 struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu);
1337 sk_release_orig_filter(fp);
1342 * sk_filter_release - release a socket filter
1343 * @fp: filter to remove
1345 * Remove a filter from a socket and release its resources.
1347 static void sk_filter_release(struct sk_filter *fp)
1349 if (atomic_dec_and_test(&fp->refcnt))
1350 call_rcu(&fp->rcu, sk_filter_release_rcu);
1353 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
1355 atomic_sub(sk_filter_size(fp->len), &sk->sk_omem_alloc);
1356 sk_filter_release(fp);
1359 void sk_filter_charge(struct sock *sk, struct sk_filter *fp)
1361 atomic_inc(&fp->refcnt);
1362 atomic_add(sk_filter_size(fp->len), &sk->sk_omem_alloc);
1365 static struct sk_filter *__sk_migrate_realloc(struct sk_filter *fp,
1369 struct sk_filter *fp_new;
1372 return krealloc(fp, len, GFP_KERNEL);
1374 fp_new = sock_kmalloc(sk, len, GFP_KERNEL);
1377 /* As we're kepping orig_prog in fp_new along,
1378 * we need to make sure we're not evicting it
1381 fp->orig_prog = NULL;
1382 sk_filter_uncharge(sk, fp);
1388 static struct sk_filter *__sk_migrate_filter(struct sk_filter *fp,
1391 struct sock_filter *old_prog;
1392 struct sk_filter *old_fp;
1393 int err, new_len, old_len = fp->len;
1395 /* We are free to overwrite insns et al right here as it
1396 * won't be used at this point in time anymore internally
1397 * after the migration to the internal BPF instruction
1400 BUILD_BUG_ON(sizeof(struct sock_filter) !=
1401 sizeof(struct sock_filter_int));
1403 /* Conversion cannot happen on overlapping memory areas,
1404 * so we need to keep the user BPF around until the 2nd
1405 * pass. At this time, the user BPF is stored in fp->insns.
1407 old_prog = kmemdup(fp->insns, old_len * sizeof(struct sock_filter),
1414 /* 1st pass: calculate the new program length. */
1415 err = sk_convert_filter(old_prog, old_len, NULL, &new_len);
1419 /* Expand fp for appending the new filter representation. */
1421 fp = __sk_migrate_realloc(old_fp, sk, sk_filter_size(new_len));
1423 /* The old_fp is still around in case we couldn't
1424 * allocate new memory, so uncharge on that one.
1433 /* 2nd pass: remap sock_filter insns into sock_filter_int insns. */
1434 err = sk_convert_filter(old_prog, old_len, fp->insnsi, &new_len);
1436 /* 2nd sk_convert_filter() can fail only if it fails
1437 * to allocate memory, remapping must succeed. Note,
1438 * that at this time old_fp has already been released
1439 * by __sk_migrate_realloc().
1443 sk_filter_select_runtime(fp);
1451 /* Rollback filter setup. */
1453 sk_filter_uncharge(sk, fp);
1456 return ERR_PTR(err);
1459 void __weak bpf_int_jit_compile(struct sk_filter *prog)
1464 * sk_filter_select_runtime - select execution runtime for BPF program
1465 * @fp: sk_filter populated with internal BPF program
1467 * try to JIT internal BPF program, if JIT is not available select interpreter
1468 * BPF program will be executed via SK_RUN_FILTER() macro
1470 void sk_filter_select_runtime(struct sk_filter *fp)
1472 fp->bpf_func = (void *) __sk_run_filter;
1474 /* Probe if internal BPF can be JITed */
1475 bpf_int_jit_compile(fp);
1477 EXPORT_SYMBOL_GPL(sk_filter_select_runtime);
1479 /* free internal BPF program */
1480 void sk_filter_free(struct sk_filter *fp)
1484 EXPORT_SYMBOL_GPL(sk_filter_free);
1486 static struct sk_filter *__sk_prepare_filter(struct sk_filter *fp,
1491 fp->bpf_func = NULL;
1494 err = sk_chk_filter(fp->insns, fp->len);
1497 sk_filter_uncharge(sk, fp);
1500 return ERR_PTR(err);
1503 /* Probe if we can JIT compile the filter and if so, do
1504 * the compilation of the filter.
1506 bpf_jit_compile(fp);
1508 /* JIT compiler couldn't process this filter, so do the
1509 * internal BPF translation for the optimized interpreter.
1512 fp = __sk_migrate_filter(fp, sk);
1518 * sk_unattached_filter_create - create an unattached filter
1519 * @fprog: the filter program
1520 * @pfp: the unattached filter that is created
1522 * Create a filter independent of any socket. We first run some
1523 * sanity checks on it to make sure it does not explode on us later.
1524 * If an error occurs or there is insufficient memory for the filter
1525 * a negative errno code is returned. On success the return is zero.
1527 int sk_unattached_filter_create(struct sk_filter **pfp,
1528 struct sock_fprog_kern *fprog)
1530 unsigned int fsize = sk_filter_proglen(fprog);
1531 struct sk_filter *fp;
1533 /* Make sure new filter is there and in the right amounts. */
1534 if (fprog->filter == NULL)
1537 fp = kmalloc(sk_filter_size(fprog->len), GFP_KERNEL);
1541 memcpy(fp->insns, fprog->filter, fsize);
1543 atomic_set(&fp->refcnt, 1);
1544 fp->len = fprog->len;
1545 /* Since unattached filters are not copied back to user
1546 * space through sk_get_filter(), we do not need to hold
1547 * a copy here, and can spare us the work.
1549 fp->orig_prog = NULL;
1551 /* __sk_prepare_filter() already takes care of uncharging
1552 * memory in case something goes wrong.
1554 fp = __sk_prepare_filter(fp, NULL);
1561 EXPORT_SYMBOL_GPL(sk_unattached_filter_create);
1563 void sk_unattached_filter_destroy(struct sk_filter *fp)
1565 sk_filter_release(fp);
1567 EXPORT_SYMBOL_GPL(sk_unattached_filter_destroy);
1570 * sk_attach_filter - attach a socket filter
1571 * @fprog: the filter program
1572 * @sk: the socket to use
1574 * Attach the user's filter code. We first run some sanity checks on
1575 * it to make sure it does not explode on us later. If an error
1576 * occurs or there is insufficient memory for the filter a negative
1577 * errno code is returned. On success the return is zero.
1579 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
1581 struct sk_filter *fp, *old_fp;
1582 unsigned int fsize = sk_filter_proglen(fprog);
1583 unsigned int sk_fsize = sk_filter_size(fprog->len);
1586 if (sock_flag(sk, SOCK_FILTER_LOCKED))
1589 /* Make sure new filter is there and in the right amounts. */
1590 if (fprog->filter == NULL)
1593 fp = sock_kmalloc(sk, sk_fsize, GFP_KERNEL);
1597 if (copy_from_user(fp->insns, fprog->filter, fsize)) {
1598 sock_kfree_s(sk, fp, sk_fsize);
1602 atomic_set(&fp->refcnt, 1);
1603 fp->len = fprog->len;
1605 err = sk_store_orig_filter(fp, fprog);
1607 sk_filter_uncharge(sk, fp);
1611 /* __sk_prepare_filter() already takes care of uncharging
1612 * memory in case something goes wrong.
1614 fp = __sk_prepare_filter(fp, sk);
1618 old_fp = rcu_dereference_protected(sk->sk_filter,
1619 sock_owned_by_user(sk));
1620 rcu_assign_pointer(sk->sk_filter, fp);
1623 sk_filter_uncharge(sk, old_fp);
1627 EXPORT_SYMBOL_GPL(sk_attach_filter);
1629 int sk_detach_filter(struct sock *sk)
1632 struct sk_filter *filter;
1634 if (sock_flag(sk, SOCK_FILTER_LOCKED))
1637 filter = rcu_dereference_protected(sk->sk_filter,
1638 sock_owned_by_user(sk));
1640 RCU_INIT_POINTER(sk->sk_filter, NULL);
1641 sk_filter_uncharge(sk, filter);
1647 EXPORT_SYMBOL_GPL(sk_detach_filter);
1649 int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf,
1652 struct sock_fprog_kern *fprog;
1653 struct sk_filter *filter;
1657 filter = rcu_dereference_protected(sk->sk_filter,
1658 sock_owned_by_user(sk));
1662 /* We're copying the filter that has been originally attached,
1663 * so no conversion/decode needed anymore.
1665 fprog = filter->orig_prog;
1669 /* User space only enquires number of filter blocks. */
1673 if (len < fprog->len)
1677 if (copy_to_user(ubuf, fprog->filter, sk_filter_proglen(fprog)))
1680 /* Instead of bytes, the API requests to return the number