| /* |
| * Linux Socket Filter - Kernel level socket filtering |
| * |
| * Based on the design of the Berkeley Packet Filter. The new |
| * internal format has been designed by PLUMgrid: |
| * |
| * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com |
| * |
| * Authors: |
| * |
| * Jay Schulist <jschlst@samba.org> |
| * Alexei Starovoitov <ast@plumgrid.com> |
| * Daniel Borkmann <dborkman@redhat.com> |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * Andi Kleen - Fix a few bad bugs and races. |
| * Kris Katterjohn - Added many additional checks in sk_chk_filter() |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/types.h> |
| #include <linux/mm.h> |
| #include <linux/fcntl.h> |
| #include <linux/socket.h> |
| #include <linux/in.h> |
| #include <linux/inet.h> |
| #include <linux/netdevice.h> |
| #include <linux/if_packet.h> |
| #include <linux/gfp.h> |
| #include <net/ip.h> |
| #include <net/protocol.h> |
| #include <net/netlink.h> |
| #include <linux/skbuff.h> |
| #include <net/sock.h> |
| #include <linux/errno.h> |
| #include <linux/timer.h> |
| #include <asm/uaccess.h> |
| #include <asm/unaligned.h> |
| #include <linux/filter.h> |
| #include <linux/ratelimit.h> |
| #include <linux/seccomp.h> |
| #include <linux/if_vlan.h> |
| |
| /* No hurry in this branch |
| * |
| * Exported for the bpf jit load helper. |
| */ |
| void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) |
| { |
| u8 *ptr = NULL; |
| |
| if (k >= SKF_NET_OFF) |
| ptr = skb_network_header(skb) + k - SKF_NET_OFF; |
| else if (k >= SKF_LL_OFF) |
| ptr = skb_mac_header(skb) + k - SKF_LL_OFF; |
| |
| if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) |
| return ptr; |
| return NULL; |
| } |
| |
| static inline void *load_pointer(const struct sk_buff *skb, int k, |
| unsigned int size, void *buffer) |
| { |
| if (k >= 0) |
| return skb_header_pointer(skb, k, size, buffer); |
| return bpf_internal_load_pointer_neg_helper(skb, k, size); |
| } |
| |
| /** |
| * sk_filter - run a packet through a socket filter |
| * @sk: sock associated with &sk_buff |
| * @skb: buffer to filter |
| * |
| * Run the filter code and then cut skb->data to correct size returned by |
| * sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller |
| * than pkt_len we keep whole skb->data. This is the socket level |
| * wrapper to sk_run_filter. It returns 0 if the packet should |
| * be accepted or -EPERM if the packet should be tossed. |
| * |
| */ |
| int sk_filter(struct sock *sk, struct sk_buff *skb) |
| { |
| int err; |
| struct sk_filter *filter; |
| |
| /* |
| * If the skb was allocated from pfmemalloc reserves, only |
| * allow SOCK_MEMALLOC sockets to use it as this socket is |
| * helping free memory |
| */ |
| if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC)) |
| return -ENOMEM; |
| |
| err = security_sock_rcv_skb(sk, skb); |
| if (err) |
| return err; |
| |
| rcu_read_lock(); |
| filter = rcu_dereference(sk->sk_filter); |
| if (filter) { |
| unsigned int pkt_len = SK_RUN_FILTER(filter, skb); |
| |
| err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM; |
| } |
| rcu_read_unlock(); |
| |
| return err; |
| } |
| EXPORT_SYMBOL(sk_filter); |
| |
| /* Base function for offset calculation. Needs to go into .text section, |
| * therefore keeping it non-static as well; will also be used by JITs |
| * anyway later on, so do not let the compiler omit it. |
| */ |
| noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) |
| { |
| return 0; |
| } |
| |
| /* Register mappings for user programs. */ |
| #define A_REG 0 |
| #define X_REG 7 |
| #define TMP_REG 8 |
| #define ARG2_REG 2 |
| #define ARG3_REG 3 |
| |
| /** |
| * __sk_run_filter - run a filter on a given context |
| * @ctx: buffer to run the filter on |
| * @insn: filter to apply |
| * |
| * Decode and apply filter instructions to the skb->data. Return length to |
| * keep, 0 for none. @ctx is the data we are operating on, @insn is the |
| * array of filter instructions. |
| */ |
| unsigned int __sk_run_filter(void *ctx, const struct sock_filter_int *insn) |
| { |
| u64 stack[MAX_BPF_STACK / sizeof(u64)]; |
| u64 regs[MAX_BPF_REG], tmp; |
| void *ptr; |
| int off; |
| |
| #define K insn->imm |
| #define A regs[insn->a_reg] |
| #define X regs[insn->x_reg] |
| #define R0 regs[0] |
| |
| #define CONT ({insn++; goto select_insn; }) |
| #define CONT_JMP ({insn++; goto select_insn; }) |
| |
| static const void *jumptable[256] = { |
| [0 ... 255] = &&default_label, |
| /* Now overwrite non-defaults ... */ |
| #define DL(A, B, C) [A|B|C] = &&A##_##B##_##C |
| DL(BPF_ALU, BPF_ADD, BPF_X), |
| DL(BPF_ALU, BPF_ADD, BPF_K), |
| DL(BPF_ALU, BPF_SUB, BPF_X), |
| DL(BPF_ALU, BPF_SUB, BPF_K), |
| DL(BPF_ALU, BPF_AND, BPF_X), |
| DL(BPF_ALU, BPF_AND, BPF_K), |
| DL(BPF_ALU, BPF_OR, BPF_X), |
| DL(BPF_ALU, BPF_OR, BPF_K), |
| DL(BPF_ALU, BPF_LSH, BPF_X), |
| DL(BPF_ALU, BPF_LSH, BPF_K), |
| DL(BPF_ALU, BPF_RSH, BPF_X), |
| DL(BPF_ALU, BPF_RSH, BPF_K), |
| DL(BPF_ALU, BPF_XOR, BPF_X), |
| DL(BPF_ALU, BPF_XOR, BPF_K), |
| DL(BPF_ALU, BPF_MUL, BPF_X), |
| DL(BPF_ALU, BPF_MUL, BPF_K), |
| DL(BPF_ALU, BPF_MOV, BPF_X), |
| DL(BPF_ALU, BPF_MOV, BPF_K), |
| DL(BPF_ALU, BPF_DIV, BPF_X), |
| DL(BPF_ALU, BPF_DIV, BPF_K), |
| DL(BPF_ALU, BPF_MOD, BPF_X), |
| DL(BPF_ALU, BPF_MOD, BPF_K), |
| DL(BPF_ALU, BPF_NEG, 0), |
| DL(BPF_ALU, BPF_END, BPF_TO_BE), |
| DL(BPF_ALU, BPF_END, BPF_TO_LE), |
| DL(BPF_ALU64, BPF_ADD, BPF_X), |
| DL(BPF_ALU64, BPF_ADD, BPF_K), |
| DL(BPF_ALU64, BPF_SUB, BPF_X), |
| DL(BPF_ALU64, BPF_SUB, BPF_K), |
| DL(BPF_ALU64, BPF_AND, BPF_X), |
| DL(BPF_ALU64, BPF_AND, BPF_K), |
| DL(BPF_ALU64, BPF_OR, BPF_X), |
| DL(BPF_ALU64, BPF_OR, BPF_K), |
| DL(BPF_ALU64, BPF_LSH, BPF_X), |
| DL(BPF_ALU64, BPF_LSH, BPF_K), |
| DL(BPF_ALU64, BPF_RSH, BPF_X), |
| DL(BPF_ALU64, BPF_RSH, BPF_K), |
| DL(BPF_ALU64, BPF_XOR, BPF_X), |
| DL(BPF_ALU64, BPF_XOR, BPF_K), |
| DL(BPF_ALU64, BPF_MUL, BPF_X), |
| DL(BPF_ALU64, BPF_MUL, BPF_K), |
| DL(BPF_ALU64, BPF_MOV, BPF_X), |
| DL(BPF_ALU64, BPF_MOV, BPF_K), |
| DL(BPF_ALU64, BPF_ARSH, BPF_X), |
| DL(BPF_ALU64, BPF_ARSH, BPF_K), |
| DL(BPF_ALU64, BPF_DIV, BPF_X), |
| DL(BPF_ALU64, BPF_DIV, BPF_K), |
| DL(BPF_ALU64, BPF_MOD, BPF_X), |
| DL(BPF_ALU64, BPF_MOD, BPF_K), |
| DL(BPF_ALU64, BPF_NEG, 0), |
| DL(BPF_JMP, BPF_CALL, 0), |
| DL(BPF_JMP, BPF_JA, 0), |
| DL(BPF_JMP, BPF_JEQ, BPF_X), |
| DL(BPF_JMP, BPF_JEQ, BPF_K), |
| DL(BPF_JMP, BPF_JNE, BPF_X), |
| DL(BPF_JMP, BPF_JNE, BPF_K), |
| DL(BPF_JMP, BPF_JGT, BPF_X), |
| DL(BPF_JMP, BPF_JGT, BPF_K), |
| DL(BPF_JMP, BPF_JGE, BPF_X), |
| DL(BPF_JMP, BPF_JGE, BPF_K), |
| DL(BPF_JMP, BPF_JSGT, BPF_X), |
| DL(BPF_JMP, BPF_JSGT, BPF_K), |
| DL(BPF_JMP, BPF_JSGE, BPF_X), |
| DL(BPF_JMP, BPF_JSGE, BPF_K), |
| DL(BPF_JMP, BPF_JSET, BPF_X), |
| DL(BPF_JMP, BPF_JSET, BPF_K), |
| DL(BPF_JMP, BPF_EXIT, 0), |
| DL(BPF_STX, BPF_MEM, BPF_B), |
| DL(BPF_STX, BPF_MEM, BPF_H), |
| DL(BPF_STX, BPF_MEM, BPF_W), |
| DL(BPF_STX, BPF_MEM, BPF_DW), |
| DL(BPF_STX, BPF_XADD, BPF_W), |
| DL(BPF_STX, BPF_XADD, BPF_DW), |
| DL(BPF_ST, BPF_MEM, BPF_B), |
| DL(BPF_ST, BPF_MEM, BPF_H), |
| DL(BPF_ST, BPF_MEM, BPF_W), |
| DL(BPF_ST, BPF_MEM, BPF_DW), |
| DL(BPF_LDX, BPF_MEM, BPF_B), |
| DL(BPF_LDX, BPF_MEM, BPF_H), |
| DL(BPF_LDX, BPF_MEM, BPF_W), |
| DL(BPF_LDX, BPF_MEM, BPF_DW), |
| DL(BPF_LD, BPF_ABS, BPF_W), |
| DL(BPF_LD, BPF_ABS, BPF_H), |
| DL(BPF_LD, BPF_ABS, BPF_B), |
| DL(BPF_LD, BPF_IND, BPF_W), |
| DL(BPF_LD, BPF_IND, BPF_H), |
| DL(BPF_LD, BPF_IND, BPF_B), |
| #undef DL |
| }; |
| |
| regs[FP_REG] = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; |
| regs[ARG1_REG] = (u64) (unsigned long) ctx; |
| regs[A_REG] = 0; |
| regs[X_REG] = 0; |
| |
| select_insn: |
| goto *jumptable[insn->code]; |
| |
| /* ALU */ |
| #define ALU(OPCODE, OP) \ |
| BPF_ALU64_##OPCODE##_BPF_X: \ |
| A = A OP X; \ |
| CONT; \ |
| BPF_ALU_##OPCODE##_BPF_X: \ |
| A = (u32) A OP (u32) X; \ |
| CONT; \ |
| BPF_ALU64_##OPCODE##_BPF_K: \ |
| A = A OP K; \ |
| CONT; \ |
| BPF_ALU_##OPCODE##_BPF_K: \ |
| A = (u32) A OP (u32) K; \ |
| CONT; |
| |
| ALU(BPF_ADD, +) |
| ALU(BPF_SUB, -) |
| ALU(BPF_AND, &) |
| ALU(BPF_OR, |) |
| ALU(BPF_LSH, <<) |
| ALU(BPF_RSH, >>) |
| ALU(BPF_XOR, ^) |
| ALU(BPF_MUL, *) |
| #undef ALU |
| BPF_ALU_BPF_NEG_0: |
| A = (u32) -A; |
| CONT; |
| BPF_ALU64_BPF_NEG_0: |
| A = -A; |
| CONT; |
| BPF_ALU_BPF_MOV_BPF_X: |
| A = (u32) X; |
| CONT; |
| BPF_ALU_BPF_MOV_BPF_K: |
| A = (u32) K; |
| CONT; |
| BPF_ALU64_BPF_MOV_BPF_X: |
| A = X; |
| CONT; |
| BPF_ALU64_BPF_MOV_BPF_K: |
| A = K; |
| CONT; |
| BPF_ALU64_BPF_ARSH_BPF_X: |
| (*(s64 *) &A) >>= X; |
| CONT; |
| BPF_ALU64_BPF_ARSH_BPF_K: |
| (*(s64 *) &A) >>= K; |
| CONT; |
| BPF_ALU64_BPF_MOD_BPF_X: |
| if (unlikely(X == 0)) |
| return 0; |
| tmp = A; |
| A = do_div(tmp, X); |
| CONT; |
| BPF_ALU_BPF_MOD_BPF_X: |
| if (unlikely(X == 0)) |
| return 0; |
| tmp = (u32) A; |
| A = do_div(tmp, (u32) X); |
| CONT; |
| BPF_ALU64_BPF_MOD_BPF_K: |
| tmp = A; |
| A = do_div(tmp, K); |
| CONT; |
| BPF_ALU_BPF_MOD_BPF_K: |
| tmp = (u32) A; |
| A = do_div(tmp, (u32) K); |
| CONT; |
| BPF_ALU64_BPF_DIV_BPF_X: |
| if (unlikely(X == 0)) |
| return 0; |
| do_div(A, X); |
| CONT; |
| BPF_ALU_BPF_DIV_BPF_X: |
| if (unlikely(X == 0)) |
| return 0; |
| tmp = (u32) A; |
| do_div(tmp, (u32) X); |
| A = (u32) tmp; |
| CONT; |
| BPF_ALU64_BPF_DIV_BPF_K: |
| do_div(A, K); |
| CONT; |
| BPF_ALU_BPF_DIV_BPF_K: |
| tmp = (u32) A; |
| do_div(tmp, (u32) K); |
| A = (u32) tmp; |
| CONT; |
| BPF_ALU_BPF_END_BPF_TO_BE: |
| switch (K) { |
| case 16: |
| A = (__force u16) cpu_to_be16(A); |
| break; |
| case 32: |
| A = (__force u32) cpu_to_be32(A); |
| break; |
| case 64: |
| A = (__force u64) cpu_to_be64(A); |
| break; |
| } |
| CONT; |
| BPF_ALU_BPF_END_BPF_TO_LE: |
| switch (K) { |
| case 16: |
| A = (__force u16) cpu_to_le16(A); |
| break; |
| case 32: |
| A = (__force u32) cpu_to_le32(A); |
| break; |
| case 64: |
| A = (__force u64) cpu_to_le64(A); |
| break; |
| } |
| CONT; |
| |
| /* CALL */ |
| BPF_JMP_BPF_CALL_0: |
| /* Function call scratches R1-R5 registers, preserves R6-R9, |
| * and stores return value into R0. |
| */ |
| R0 = (__bpf_call_base + insn->imm)(regs[1], regs[2], regs[3], |
| regs[4], regs[5]); |
| CONT; |
| |
| /* JMP */ |
| BPF_JMP_BPF_JA_0: |
| insn += insn->off; |
| CONT; |
| BPF_JMP_BPF_JEQ_BPF_X: |
| if (A == X) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JEQ_BPF_K: |
| if (A == K) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JNE_BPF_X: |
| if (A != X) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JNE_BPF_K: |
| if (A != K) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JGT_BPF_X: |
| if (A > X) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JGT_BPF_K: |
| if (A > K) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JGE_BPF_X: |
| if (A >= X) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JGE_BPF_K: |
| if (A >= K) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JSGT_BPF_X: |
| if (((s64)A) > ((s64)X)) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JSGT_BPF_K: |
| if (((s64)A) > ((s64)K)) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JSGE_BPF_X: |
| if (((s64)A) >= ((s64)X)) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JSGE_BPF_K: |
| if (((s64)A) >= ((s64)K)) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JSET_BPF_X: |
| if (A & X) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_JSET_BPF_K: |
| if (A & K) { |
| insn += insn->off; |
| CONT_JMP; |
| } |
| CONT; |
| BPF_JMP_BPF_EXIT_0: |
| return R0; |
| |
| /* STX and ST and LDX*/ |
| #define LDST(SIZEOP, SIZE) \ |
| BPF_STX_BPF_MEM_##SIZEOP: \ |
| *(SIZE *)(unsigned long) (A + insn->off) = X; \ |
| CONT; \ |
| BPF_ST_BPF_MEM_##SIZEOP: \ |
| *(SIZE *)(unsigned long) (A + insn->off) = K; \ |
| CONT; \ |
| BPF_LDX_BPF_MEM_##SIZEOP: \ |
| A = *(SIZE *)(unsigned long) (X + insn->off); \ |
| CONT; |
| |
| LDST(BPF_B, u8) |
| LDST(BPF_H, u16) |
| LDST(BPF_W, u32) |
| LDST(BPF_DW, u64) |
| #undef LDST |
| BPF_STX_BPF_XADD_BPF_W: /* lock xadd *(u32 *)(A + insn->off) += X */ |
| atomic_add((u32) X, (atomic_t *)(unsigned long) |
| (A + insn->off)); |
| CONT; |
| BPF_STX_BPF_XADD_BPF_DW: /* lock xadd *(u64 *)(A + insn->off) += X */ |
| atomic64_add((u64) X, (atomic64_t *)(unsigned long) |
| (A + insn->off)); |
| CONT; |
| BPF_LD_BPF_ABS_BPF_W: /* R0 = ntohl(*(u32 *) (skb->data + K)) */ |
| off = K; |
| load_word: |
| /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are only |
| * appearing in the programs where ctx == skb. All programs |
| * keep 'ctx' in regs[CTX_REG] == R6, sk_convert_filter() |
| * saves it in R6, internal BPF verifier will check that |
| * R6 == ctx. |
| * |
| * BPF_ABS and BPF_IND are wrappers of function calls, so |
| * they scratch R1-R5 registers, preserve R6-R9, and store |
| * return value into R0. |
| * |
| * Implicit input: |
| * ctx |
| * |
| * Explicit input: |
| * X == any register |
| * K == 32-bit immediate |
| * |
| * Output: |
| * R0 - 8/16/32-bit skb data converted to cpu endianness |
| */ |
| ptr = load_pointer((struct sk_buff *) ctx, off, 4, &tmp); |
| if (likely(ptr != NULL)) { |
| R0 = get_unaligned_be32(ptr); |
| CONT; |
| } |
| return 0; |
| BPF_LD_BPF_ABS_BPF_H: /* R0 = ntohs(*(u16 *) (skb->data + K)) */ |
| off = K; |
| load_half: |
| ptr = load_pointer((struct sk_buff *) ctx, off, 2, &tmp); |
| if (likely(ptr != NULL)) { |
| R0 = get_unaligned_be16(ptr); |
| CONT; |
| } |
| return 0; |
| BPF_LD_BPF_ABS_BPF_B: /* R0 = *(u8 *) (ctx + K) */ |
| off = K; |
| load_byte: |
| ptr = load_pointer((struct sk_buff *) ctx, off, 1, &tmp); |
| if (likely(ptr != NULL)) { |
| R0 = *(u8 *)ptr; |
| CONT; |
| } |
| return 0; |
| BPF_LD_BPF_IND_BPF_W: /* R0 = ntohl(*(u32 *) (skb->data + X + K)) */ |
| off = K + X; |
| goto load_word; |
| BPF_LD_BPF_IND_BPF_H: /* R0 = ntohs(*(u16 *) (skb->data + X + K)) */ |
| off = K + X; |
| goto load_half; |
| BPF_LD_BPF_IND_BPF_B: /* R0 = *(u8 *) (skb->data + X + K) */ |
| off = K + X; |
| goto load_byte; |
| |
| default_label: |
| /* If we ever reach this, we have a bug somewhere. */ |
| WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code); |
| return 0; |
| #undef CONT_JMP |
| #undef CONT |
| |
| #undef R0 |
| #undef X |
| #undef A |
| #undef K |
| } |
| |
| u32 sk_run_filter_int_seccomp(const struct seccomp_data *ctx, |
| const struct sock_filter_int *insni) |
| __attribute__ ((alias ("__sk_run_filter"))); |
| |
| u32 sk_run_filter_int_skb(const struct sk_buff *ctx, |
| const struct sock_filter_int *insni) |
| __attribute__ ((alias ("__sk_run_filter"))); |
| EXPORT_SYMBOL_GPL(sk_run_filter_int_skb); |
| |
| /* Helper to find the offset of pkt_type in sk_buff structure. We want |
| * to make sure its still a 3bit field starting at a byte boundary; |
| * taken from arch/x86/net/bpf_jit_comp.c. |
| */ |
| #define PKT_TYPE_MAX 7 |
| static unsigned int pkt_type_offset(void) |
| { |
| struct sk_buff skb_probe = { .pkt_type = ~0, }; |
| u8 *ct = (u8 *) &skb_probe; |
| unsigned int off; |
| |
| for (off = 0; off < sizeof(struct sk_buff); off++) { |
| if (ct[off] == PKT_TYPE_MAX) |
| return off; |
| } |
| |
| pr_err_once("Please fix %s, as pkt_type couldn't be found!\n", __func__); |
| return -1; |
| } |
| |
| static u64 __skb_get_pay_offset(u64 ctx, u64 A, u64 X, u64 r4, u64 r5) |
| { |
| struct sk_buff *skb = (struct sk_buff *)(long) ctx; |
| |
| return __skb_get_poff(skb); |
| } |
| |
| static u64 __skb_get_nlattr(u64 ctx, u64 A, u64 X, u64 r4, u64 r5) |
| { |
| struct sk_buff *skb = (struct sk_buff *)(long) ctx; |
| struct nlattr *nla; |
| |
| if (skb_is_nonlinear(skb)) |
| return 0; |
| |
| if (skb->len < sizeof(struct nlattr)) |
| return 0; |
| |
| if (A > skb->len - sizeof(struct nlattr)) |
| return 0; |
| |
| nla = nla_find((struct nlattr *) &skb->data[A], skb->len - A, X); |
| if (nla) |
| return (void *) nla - (void *) skb->data; |
| |
| return 0; |
| } |
| |
| static u64 __skb_get_nlattr_nest(u64 ctx, u64 A, u64 X, u64 r4, u64 r5) |
| { |
| struct sk_buff *skb = (struct sk_buff *)(long) ctx; |
| struct nlattr *nla; |
| |
| if (skb_is_nonlinear(skb)) |
| return 0; |
| |
| if (skb->len < sizeof(struct nlattr)) |
| return 0; |
| |
| if (A > skb->len - sizeof(struct nlattr)) |
| return 0; |
| |
| nla = (struct nlattr *) &skb->data[A]; |
| if (nla->nla_len > skb->len - A) |
| return 0; |
| |
| nla = nla_find_nested(nla, X); |
| if (nla) |
| return (void *) nla - (void *) skb->data; |
| |
| return 0; |
| } |
| |
| static u64 __get_raw_cpu_id(u64 ctx, u64 A, u64 X, u64 r4, u64 r5) |
| { |
| return raw_smp_processor_id(); |
| } |
| |
| static bool convert_bpf_extensions(struct sock_filter *fp, |
| struct sock_filter_int **insnp) |
| { |
| struct sock_filter_int *insn = *insnp; |
| |
| switch (fp->k) { |
| case SKF_AD_OFF + SKF_AD_PROTOCOL: |
| BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2); |
| |
| insn->code = BPF_LDX | BPF_MEM | BPF_H; |
| insn->a_reg = A_REG; |
| insn->x_reg = CTX_REG; |
| insn->off = offsetof(struct sk_buff, protocol); |
| insn++; |
| |
| /* A = ntohs(A) [emitting a nop or swap16] */ |
| insn->code = BPF_ALU | BPF_END | BPF_FROM_BE; |
| insn->a_reg = A_REG; |
| insn->imm = 16; |
| break; |
| |
| case SKF_AD_OFF + SKF_AD_PKTTYPE: |
| insn->code = BPF_LDX | BPF_MEM | BPF_B; |
| insn->a_reg = A_REG; |
| insn->x_reg = CTX_REG; |
| insn->off = pkt_type_offset(); |
| if (insn->off < 0) |
| return false; |
| insn++; |
| |
| insn->code = BPF_ALU | BPF_AND | BPF_K; |
| insn->a_reg = A_REG; |
| insn->imm = PKT_TYPE_MAX; |
| break; |
| |
| case SKF_AD_OFF + SKF_AD_IFINDEX: |
| case SKF_AD_OFF + SKF_AD_HATYPE: |
| if (FIELD_SIZEOF(struct sk_buff, dev) == 8) |
| insn->code = BPF_LDX | BPF_MEM | BPF_DW; |
| else |
| insn->code = BPF_LDX | BPF_MEM | BPF_W; |
| insn->a_reg = TMP_REG; |
| insn->x_reg = CTX_REG; |
| insn->off = offsetof(struct sk_buff, dev); |
| insn++; |
| |
| insn->code = BPF_JMP | BPF_JNE | BPF_K; |
| insn->a_reg = TMP_REG; |
| insn->imm = 0; |
| insn->off = 1; |
| insn++; |
| |
| insn->code = BPF_JMP | BPF_EXIT; |
| insn++; |
| |
| BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); |
| BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2); |
| |
| insn->a_reg = A_REG; |
| insn->x_reg = TMP_REG; |
| |
| if (fp->k == SKF_AD_OFF + SKF_AD_IFINDEX) { |
| insn->code = BPF_LDX | BPF_MEM | BPF_W; |
| insn->off = offsetof(struct net_device, ifindex); |
| } else { |
| insn->code = BPF_LDX | BPF_MEM | BPF_H; |
| insn->off = offsetof(struct net_device, type); |
| } |
| break; |
| |
| case SKF_AD_OFF + SKF_AD_MARK: |
| BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); |
| |
| insn->code = BPF_LDX | BPF_MEM | BPF_W; |
| insn->a_reg = A_REG; |
| insn->x_reg = CTX_REG; |
| insn->off = offsetof(struct sk_buff, mark); |
| break; |
| |
| case SKF_AD_OFF + SKF_AD_RXHASH: |
| BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4); |
| |
| insn->code = BPF_LDX | BPF_MEM | BPF_W; |
| insn->a_reg = A_REG; |
| insn->x_reg = CTX_REG; |
| insn->off = offsetof(struct sk_buff, hash); |
| break; |
| |
| case SKF_AD_OFF + SKF_AD_QUEUE: |
| BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2); |
| |
| insn->code = BPF_LDX | BPF_MEM | BPF_H; |
| insn->a_reg = A_REG; |
| insn->x_reg = CTX_REG; |
| insn->off = offsetof(struct sk_buff, queue_mapping); |
| break; |
| |
| case SKF_AD_OFF + SKF_AD_VLAN_TAG: |
| case SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT: |
| BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2); |
| |
| insn->code = BPF_LDX | BPF_MEM | BPF_H; |
| insn->a_reg = A_REG; |
| insn->x_reg = CTX_REG; |
| insn->off = offsetof(struct sk_buff, vlan_tci); |
| insn++; |
| |
| BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000); |
| |
| if (fp->k == SKF_AD_OFF + SKF_AD_VLAN_TAG) { |
| insn->code = BPF_ALU | BPF_AND | BPF_K; |
| insn->a_reg = A_REG; |
| insn->imm = ~VLAN_TAG_PRESENT; |
| } else { |
| insn->code = BPF_ALU | BPF_RSH | BPF_K; |
| insn->a_reg = A_REG; |
| insn->imm = 12; |
| insn++; |
| |
| insn->code = BPF_ALU | BPF_AND | BPF_K; |
| insn->a_reg = A_REG; |
| insn->imm = 1; |
| } |
| break; |
| |
| case SKF_AD_OFF + SKF_AD_PAY_OFFSET: |
| case SKF_AD_OFF + SKF_AD_NLATTR: |
| case SKF_AD_OFF + SKF_AD_NLATTR_NEST: |
| case SKF_AD_OFF + SKF_AD_CPU: |
| /* arg1 = ctx */ |
| insn->code = BPF_ALU64 | BPF_MOV | BPF_X; |
| insn->a_reg = ARG1_REG; |
| insn->x_reg = CTX_REG; |
| insn++; |
| |
| /* arg2 = A */ |
| insn->code = BPF_ALU64 | BPF_MOV | BPF_X; |
| insn->a_reg = ARG2_REG; |
| insn->x_reg = A_REG; |
| insn++; |
| |
| /* arg3 = X */ |
| insn->code = BPF_ALU64 | BPF_MOV | BPF_X; |
| insn->a_reg = ARG3_REG; |
| insn->x_reg = X_REG; |
| insn++; |
| |
| /* Emit call(ctx, arg2=A, arg3=X) */ |
| insn->code = BPF_JMP | BPF_CALL; |
| switch (fp->k) { |
| case SKF_AD_OFF + SKF_AD_PAY_OFFSET: |
| insn->imm = __skb_get_pay_offset - __bpf_call_base; |
| break; |
| case SKF_AD_OFF + SKF_AD_NLATTR: |
| insn->imm = __skb_get_nlattr - __bpf_call_base; |
| break; |
| case SKF_AD_OFF + SKF_AD_NLATTR_NEST: |
| insn->imm = __skb_get_nlattr_nest - __bpf_call_base; |
| break; |
| case SKF_AD_OFF + SKF_AD_CPU: |
| insn->imm = __get_raw_cpu_id - __bpf_call_base; |
| break; |
| } |
| break; |
| |
| case SKF_AD_OFF + SKF_AD_ALU_XOR_X: |
| insn->code = BPF_ALU | BPF_XOR | BPF_X; |
| insn->a_reg = A_REG; |
| insn->x_reg = X_REG; |
| break; |
| |
| default: |
| /* This is just a dummy call to avoid letting the compiler |
| * evict __bpf_call_base() as an optimization. Placed here |
| * where no-one bothers. |
| */ |
| BUG_ON(__bpf_call_base(0, 0, 0, 0, 0) != 0); |
| return false; |
| } |
| |
| *insnp = insn; |
| return true; |
| } |
| |
| /** |
| * sk_convert_filter - convert filter program |
| * @prog: the user passed filter program |
| * @len: the length of the user passed filter program |
| * @new_prog: buffer where converted program will be stored |
| * @new_len: pointer to store length of converted program |
| * |
| * Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style. |
| * Conversion workflow: |
| * |
| * 1) First pass for calculating the new program length: |
| * sk_convert_filter(old_prog, old_len, NULL, &new_len) |
| * |
| * 2) 2nd pass to remap in two passes: 1st pass finds new |
| * jump offsets, 2nd pass remapping: |
| * new_prog = kmalloc(sizeof(struct sock_filter_int) * new_len); |
| * sk_convert_filter(old_prog, old_len, new_prog, &new_len); |
| * |
| * User BPF's register A is mapped to our BPF register 6, user BPF |
| * register X is mapped to BPF register 7; frame pointer is always |
| * register 10; Context 'void *ctx' is stored in register 1, that is, |
| * for socket filters: ctx == 'struct sk_buff *', for seccomp: |
| * ctx == 'struct seccomp_data *'. |
| */ |
| int sk_convert_filter(struct sock_filter *prog, int len, |
| struct sock_filter_int *new_prog, int *new_len) |
| { |
| int new_flen = 0, pass = 0, target, i; |
| struct sock_filter_int *new_insn; |
| struct sock_filter *fp; |
| int *addrs = NULL; |
| u8 bpf_src; |
| |
| BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK); |
| BUILD_BUG_ON(FP_REG + 1 != MAX_BPF_REG); |
| |
| if (len <= 0 || len >= BPF_MAXINSNS) |
| return -EINVAL; |
| |
| if (new_prog) { |
| addrs = kzalloc(len * sizeof(*addrs), GFP_KERNEL); |
| if (!addrs) |
| return -ENOMEM; |
| } |
| |
| do_pass: |
| new_insn = new_prog; |
| fp = prog; |
| |
| if (new_insn) { |
| new_insn->code = BPF_ALU64 | BPF_MOV | BPF_X; |
| new_insn->a_reg = CTX_REG; |
| new_insn->x_reg = ARG1_REG; |
| } |
| new_insn++; |
| |
| for (i = 0; i < len; fp++, i++) { |
| struct sock_filter_int tmp_insns[6] = { }; |
| struct sock_filter_int *insn = tmp_insns; |
| |
| if (addrs) |
| addrs[i] = new_insn - new_prog; |
| |
| switch (fp->code) { |
| /* All arithmetic insns and skb loads map as-is. */ |
| case BPF_ALU | BPF_ADD | BPF_X: |
| case BPF_ALU | BPF_ADD | BPF_K: |
| case BPF_ALU | BPF_SUB | BPF_X: |
| case BPF_ALU | BPF_SUB | BPF_K: |
| case BPF_ALU | BPF_AND | BPF_X: |
| case BPF_ALU | BPF_AND | BPF_K: |
| case BPF_ALU | BPF_OR | BPF_X: |
| case BPF_ALU | BPF_OR | BPF_K: |
| case BPF_ALU | BPF_LSH | BPF_X: |
| case BPF_ALU | BPF_LSH | BPF_K: |
| case BPF_ALU | BPF_RSH | BPF_X: |
| case BPF_ALU | BPF_RSH | BPF_K: |
| case BPF_ALU | BPF_XOR | BPF_X: |
| case BPF_ALU | BPF_XOR | BPF_K: |
| case BPF_ALU | BPF_MUL | BPF_X: |
| case BPF_ALU | BPF_MUL | BPF_K: |
| case BPF_ALU | BPF_DIV | BPF_X: |
| case BPF_ALU | BPF_DIV | BPF_K: |
| case BPF_ALU | BPF_MOD | BPF_X: |
| case BPF_ALU | BPF_MOD | BPF_K: |
| case BPF_ALU | BPF_NEG: |
| case BPF_LD | BPF_ABS | BPF_W: |
| case BPF_LD | BPF_ABS | BPF_H: |
| case BPF_LD | BPF_ABS | BPF_B: |
| case BPF_LD | BPF_IND | BPF_W: |
| case BPF_LD | BPF_IND | BPF_H: |
| case BPF_LD | BPF_IND | BPF_B: |
| /* Check for overloaded BPF extension and |
| * directly convert it if found, otherwise |
| * just move on with mapping. |
| */ |
| if (BPF_CLASS(fp->code) == BPF_LD && |
| BPF_MODE(fp->code) == BPF_ABS && |
| convert_bpf_extensions(fp, &insn)) |
| break; |
| |
| insn->code = fp->code; |
| insn->a_reg = A_REG; |
| insn->x_reg = X_REG; |
| insn->imm = fp->k; |
| break; |
| |
| /* Jump opcodes map as-is, but offsets need adjustment. */ |
| case BPF_JMP | BPF_JA: |
| target = i + fp->k + 1; |
| insn->code = fp->code; |
| #define EMIT_JMP \ |
| do { \ |
| if (target >= len || target < 0) \ |
| goto err; \ |
| insn->off = addrs ? addrs[target] - addrs[i] - 1 : 0; \ |
| /* Adjust pc relative offset for 2nd or 3rd insn. */ \ |
| insn->off -= insn - tmp_insns; \ |
| } while (0) |
| |
| EMIT_JMP; |
| break; |
| |
| case BPF_JMP | BPF_JEQ | BPF_K: |
| case BPF_JMP | BPF_JEQ | BPF_X: |
| case BPF_JMP | BPF_JSET | BPF_K: |
| case BPF_JMP | BPF_JSET | BPF_X: |
| case BPF_JMP | BPF_JGT | BPF_K: |
| case BPF_JMP | BPF_JGT | BPF_X: |
| case BPF_JMP | BPF_JGE | BPF_K: |
| case BPF_JMP | BPF_JGE | BPF_X: |
| if (BPF_SRC(fp->code) == BPF_K && (int) fp->k < 0) { |
| /* BPF immediates are signed, zero extend |
| * immediate into tmp register and use it |
| * in compare insn. |
| */ |
| insn->code = BPF_ALU | BPF_MOV | BPF_K; |
| insn->a_reg = TMP_REG; |
| insn->imm = fp->k; |
| insn++; |
| |
| insn->a_reg = A_REG; |
| insn->x_reg = TMP_REG; |
| bpf_src = BPF_X; |
| } else { |
| insn->a_reg = A_REG; |
| insn->x_reg = X_REG; |
| insn->imm = fp->k; |
| bpf_src = BPF_SRC(fp->code); |
| } |
| |
| /* Common case where 'jump_false' is next insn. */ |
| if (fp->jf == 0) { |
| insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src; |
| target = i + fp->jt + 1; |
| EMIT_JMP; |
| break; |
| } |
| |
| /* Convert JEQ into JNE when 'jump_true' is next insn. */ |
| if (fp->jt == 0 && BPF_OP(fp->code) == BPF_JEQ) { |
| insn->code = BPF_JMP | BPF_JNE | bpf_src; |
| target = i + fp->jf + 1; |
| EMIT_JMP; |
| break; |
| } |
| |
| /* Other jumps are mapped into two insns: Jxx and JA. */ |
| target = i + fp->jt + 1; |
| insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src; |
| EMIT_JMP; |
| insn++; |
| |
| insn->code = BPF_JMP | BPF_JA; |
| target = i + fp->jf + 1; |
| EMIT_JMP; |
| break; |
| |
| /* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */ |
| case BPF_LDX | BPF_MSH | BPF_B: |
| insn->code = BPF_ALU64 | BPF_MOV | BPF_X; |
| insn->a_reg = TMP_REG; |
| insn->x_reg = A_REG; |
| insn++; |
| |
| insn->code = BPF_LD | BPF_ABS | BPF_B; |
| insn->a_reg = A_REG; |
| insn->imm = fp->k; |
| insn++; |
| |
| insn->code = BPF_ALU | BPF_AND | BPF_K; |
| insn->a_reg = A_REG; |
| insn->imm = 0xf; |
| insn++; |
| |
| insn->code = BPF_ALU | BPF_LSH | BPF_K; |
| insn->a_reg = A_REG; |
| insn->imm = 2; |
| insn++; |
| |
| insn->code = BPF_ALU64 | BPF_MOV | BPF_X; |
| insn->a_reg = X_REG; |
| insn->x_reg = A_REG; |
| insn++; |
| |
| insn->code = BPF_ALU64 | BPF_MOV | BPF_X; |
| insn->a_reg = A_REG; |
| insn->x_reg = TMP_REG; |
| break; |
| |
| /* RET_K, RET_A are remaped into 2 insns. */ |
| case BPF_RET | BPF_A: |
| case BPF_RET | BPF_K: |
| insn->code = BPF_ALU | BPF_MOV | |
| (BPF_RVAL(fp->code) == BPF_K ? |
| BPF_K : BPF_X); |
| insn->a_reg = 0; |
| insn->x_reg = A_REG; |
| insn->imm = fp->k; |
| insn++; |
| |
| insn->code = BPF_JMP | BPF_EXIT; |
| break; |
| |
| /* Store to stack. */ |
| case BPF_ST: |
| case BPF_STX: |
| insn->code = BPF_STX | BPF_MEM | BPF_W; |
| insn->a_reg = FP_REG; |
| insn->x_reg = fp->code == BPF_ST ? A_REG : X_REG; |
| insn->off = -(BPF_MEMWORDS - fp->k) * 4; |
| break; |
| |
| /* Load from stack. */ |
| case BPF_LD | BPF_MEM: |
| case BPF_LDX | BPF_MEM: |
| insn->code = BPF_LDX | BPF_MEM | BPF_W; |
| insn->a_reg = BPF_CLASS(fp->code) == BPF_LD ? |
| A_REG : X_REG; |
| insn->x_reg = FP_REG; |
| insn->off = -(BPF_MEMWORDS - fp->k) * 4; |
| break; |
| |
| /* A = K or X = K */ |
| case BPF_LD | BPF_IMM: |
| case BPF_LDX | BPF_IMM: |
| insn->code = BPF_ALU | BPF_MOV | BPF_K; |
| insn->a_reg = BPF_CLASS(fp->code) == BPF_LD ? |
| A_REG : X_REG; |
| insn->imm = fp->k; |
| break; |
| |
| /* X = A */ |
| case BPF_MISC | BPF_TAX: |
| insn->code = BPF_ALU64 | BPF_MOV | BPF_X; |
| insn->a_reg = X_REG; |
| insn->x_reg = A_REG; |
| break; |
| |
| /* A = X */ |
| case BPF_MISC | BPF_TXA: |
| insn->code = BPF_ALU64 | BPF_MOV | BPF_X; |
| insn->a_reg = A_REG; |
| insn->x_reg = X_REG; |
| break; |
| |
| /* A = skb->len or X = skb->len */ |
| case BPF_LD | BPF_W | BPF_LEN: |
| case BPF_LDX | BPF_W | BPF_LEN: |
| insn->code = BPF_LDX | BPF_MEM | BPF_W; |
| insn->a_reg = BPF_CLASS(fp->code) == BPF_LD ? |
| A_REG : X_REG; |
| insn->x_reg = CTX_REG; |
| insn->off = offsetof(struct sk_buff, len); |
| break; |
| |
| /* access seccomp_data fields */ |
| case BPF_LDX | BPF_ABS | BPF_W: |
| insn->code = BPF_LDX | BPF_MEM | BPF_W; |
| insn->a_reg = A_REG; |
| insn->x_reg = CTX_REG; |
| insn->off = fp->k; |
| break; |
| |
| default: |
| goto err; |
| } |
| |
| insn++; |
| if (new_prog) |
| memcpy(new_insn, tmp_insns, |
| sizeof(*insn) * (insn - tmp_insns)); |
| |
| new_insn += insn - tmp_insns; |
| } |
| |
| if (!new_prog) { |
| /* Only calculating new length. */ |
| *new_len = new_insn - new_prog; |
| return 0; |
| } |
| |
| pass++; |
| if (new_flen != new_insn - new_prog) { |
| new_flen = new_insn - new_prog; |
| if (pass > 2) |
| goto err; |
| |
| goto do_pass; |
| } |
| |
| kfree(addrs); |
| BUG_ON(*new_len != new_flen); |
| return 0; |
| err: |
| kfree(addrs); |
| return -EINVAL; |
| } |
| |
| /* Security: |
| * |
| * A BPF program is able to use 16 cells of memory to store intermediate |
| * values (check u32 mem[BPF_MEMWORDS] in sk_run_filter()). |
| * |
| * As we dont want to clear mem[] array for each packet going through |
| * sk_run_filter(), we check that filter loaded by user never try to read |
| * a cell if not previously written, and we check all branches to be sure |
| * a malicious user doesn't try to abuse us. |
| */ |
| static int check_load_and_stores(struct sock_filter *filter, int flen) |
| { |
| u16 *masks, memvalid = 0; /* one bit per cell, 16 cells */ |
| int pc, ret = 0; |
| |
| BUILD_BUG_ON(BPF_MEMWORDS > 16); |
| masks = kmalloc(flen * sizeof(*masks), GFP_KERNEL); |
| if (!masks) |
| return -ENOMEM; |
| memset(masks, 0xff, flen * sizeof(*masks)); |
| |
| for (pc = 0; pc < flen; pc++) { |
| memvalid &= masks[pc]; |
| |
| switch (filter[pc].code) { |
| case BPF_S_ST: |
| case BPF_S_STX: |
| memvalid |= (1 << filter[pc].k); |
| break; |
| case BPF_S_LD_MEM: |
| case BPF_S_LDX_MEM: |
| if (!(memvalid & (1 << filter[pc].k))) { |
| ret = -EINVAL; |
| goto error; |
| } |
| break; |
| case BPF_S_JMP_JA: |
| /* a jump must set masks on target */ |
| masks[pc + 1 + filter[pc].k] &= memvalid; |
| memvalid = ~0; |
| break; |
| case BPF_S_JMP_JEQ_K: |
| case BPF_S_JMP_JEQ_X: |
| case BPF_S_JMP_JGE_K: |
| case BPF_S_JMP_JGE_X: |
| case BPF_S_JMP_JGT_K: |
| case BPF_S_JMP_JGT_X: |
| case BPF_S_JMP_JSET_X: |
| case BPF_S_JMP_JSET_K: |
| /* a jump must set masks on targets */ |
| masks[pc + 1 + filter[pc].jt] &= memvalid; |
| masks[pc + 1 + filter[pc].jf] &= memvalid; |
| memvalid = ~0; |
| break; |
| } |
| } |
| error: |
| kfree(masks); |
| return ret; |
| } |
| |
| /** |
| * sk_chk_filter - verify socket filter code |
| * @filter: filter to verify |
| * @flen: length of filter |
| * |
| * Check the user's filter code. If we let some ugly |
| * filter code slip through kaboom! The filter must contain |
| * no references or jumps that are out of range, no illegal |
| * instructions, and must end with a RET instruction. |
| * |
| * All jumps are forward as they are not signed. |
| * |
| * Returns 0 if the rule set is legal or -EINVAL if not. |
| */ |
| int sk_chk_filter(struct sock_filter *filter, unsigned int flen) |
| { |
| /* |
| * Valid instructions are initialized to non-0. |
| * Invalid instructions are initialized to 0. |
| */ |
| static const u8 codes[] = { |
| [BPF_ALU|BPF_ADD|BPF_K] = BPF_S_ALU_ADD_K, |
| [BPF_ALU|BPF_ADD|BPF_X] = BPF_S_ALU_ADD_X, |
| [BPF_ALU|BPF_SUB|BPF_K] = BPF_S_ALU_SUB_K, |
| [BPF_ALU|BPF_SUB|BPF_X] = BPF_S_ALU_SUB_X, |
| [BPF_ALU|BPF_MUL|BPF_K] = BPF_S_ALU_MUL_K, |
| [BPF_ALU|BPF_MUL|BPF_X] = BPF_S_ALU_MUL_X, |
| [BPF_ALU|BPF_DIV|BPF_X] = BPF_S_ALU_DIV_X, |
| [BPF_ALU|BPF_MOD|BPF_K] = BPF_S_ALU_MOD_K, |
| [BPF_ALU|BPF_MOD|BPF_X] = BPF_S_ALU_MOD_X, |
| [BPF_ALU|BPF_AND|BPF_K] = BPF_S_ALU_AND_K, |
| [BPF_ALU|BPF_AND|BPF_X] = BPF_S_ALU_AND_X, |
| [BPF_ALU|BPF_OR|BPF_K] = BPF_S_ALU_OR_K, |
| [BPF_ALU|BPF_OR|BPF_X] = BPF_S_ALU_OR_X, |
| [BPF_ALU|BPF_XOR|BPF_K] = BPF_S_ALU_XOR_K, |
| [BPF_ALU|BPF_XOR|BPF_X] = BPF_S_ALU_XOR_X, |
| [BPF_ALU|BPF_LSH|BPF_K] = BPF_S_ALU_LSH_K, |
| [BPF_ALU|BPF_LSH|BPF_X] = BPF_S_ALU_LSH_X, |
| [BPF_ALU|BPF_RSH|BPF_K] = BPF_S_ALU_RSH_K, |
| [BPF_ALU|BPF_RSH|BPF_X] = BPF_S_ALU_RSH_X, |
| [BPF_ALU|BPF_NEG] = BPF_S_ALU_NEG, |
| [BPF_LD|BPF_W|BPF_ABS] = BPF_S_LD_W_ABS, |
| [BPF_LD|BPF_H|BPF_ABS] = BPF_S_LD_H_ABS, |
| [BPF_LD|BPF_B|BPF_ABS] = BPF_S_LD_B_ABS, |
| [BPF_LD|BPF_W|BPF_LEN] = BPF_S_LD_W_LEN, |
| [BPF_LD|BPF_W|BPF_IND] = BPF_S_LD_W_IND, |
| [BPF_LD|BPF_H|BPF_IND] = BPF_S_LD_H_IND, |
| [BPF_LD|BPF_B|BPF_IND] = BPF_S_LD_B_IND, |
| [BPF_LD|BPF_IMM] = BPF_S_LD_IMM, |
| [BPF_LDX|BPF_W|BPF_LEN] = BPF_S_LDX_W_LEN, |
| [BPF_LDX|BPF_B|BPF_MSH] = BPF_S_LDX_B_MSH, |
| [BPF_LDX|BPF_IMM] = BPF_S_LDX_IMM, |
| [BPF_MISC|BPF_TAX] = BPF_S_MISC_TAX, |
| [BPF_MISC|BPF_TXA] = BPF_S_MISC_TXA, |
| [BPF_RET|BPF_K] = BPF_S_RET_K, |
| [BPF_RET|BPF_A] = BPF_S_RET_A, |
| [BPF_ALU|BPF_DIV|BPF_K] = BPF_S_ALU_DIV_K, |
| [BPF_LD|BPF_MEM] = BPF_S_LD_MEM, |
| [BPF_LDX|BPF_MEM] = BPF_S_LDX_MEM, |
| [BPF_ST] = BPF_S_ST, |
| [BPF_STX] = BPF_S_STX, |
| [BPF_JMP|BPF_JA] = BPF_S_JMP_JA, |
| [BPF_JMP|BPF_JEQ|BPF_K] = BPF_S_JMP_JEQ_K, |
| [BPF_JMP|BPF_JEQ|BPF_X] = BPF_S_JMP_JEQ_X, |
| [BPF_JMP|BPF_JGE|BPF_K] = BPF_S_JMP_JGE_K, |
| [BPF_JMP|BPF_JGE|BPF_X] = BPF_S_JMP_JGE_X, |
| [BPF_JMP|BPF_JGT|BPF_K] = BPF_S_JMP_JGT_K, |
| [BPF_JMP|BPF_JGT|BPF_X] = BPF_S_JMP_JGT_X, |
| [BPF_JMP|BPF_JSET|BPF_K] = BPF_S_JMP_JSET_K, |
| [BPF_JMP|BPF_JSET|BPF_X] = BPF_S_JMP_JSET_X, |
| }; |
| int pc; |
| bool anc_found; |
| |
| if (flen == 0 || flen > BPF_MAXINSNS) |
| return -EINVAL; |
| |
| /* check the filter code now */ |
| for (pc = 0; pc < flen; pc++) { |
| struct sock_filter *ftest = &filter[pc]; |
| u16 code = ftest->code; |
| |
| if (code >= ARRAY_SIZE(codes)) |
| return -EINVAL; |
| code = codes[code]; |
| if (!code) |
| return -EINVAL; |
| /* Some instructions need special checks */ |
| switch (code) { |
| case BPF_S_ALU_DIV_K: |
| case BPF_S_ALU_MOD_K: |
| /* check for division by zero */ |
| if (ftest->k == 0) |
| return -EINVAL; |
| break; |
| case BPF_S_LD_MEM: |
| case BPF_S_LDX_MEM: |
| case BPF_S_ST: |
| case BPF_S_STX: |
| /* check for invalid memory addresses */ |
| if (ftest->k >= BPF_MEMWORDS) |
| return -EINVAL; |
| break; |
| case BPF_S_JMP_JA: |
| /* |
| * Note, the large ftest->k might cause loops. |
| * Compare this with conditional jumps below, |
| * where offsets are limited. --ANK (981016) |
| */ |
| if (ftest->k >= (unsigned int)(flen-pc-1)) |
| return -EINVAL; |
| break; |
| case BPF_S_JMP_JEQ_K: |
| case BPF_S_JMP_JEQ_X: |
| case BPF_S_JMP_JGE_K: |
| case BPF_S_JMP_JGE_X: |
| case BPF_S_JMP_JGT_K: |
| case BPF_S_JMP_JGT_X: |
| case BPF_S_JMP_JSET_X: |
| case BPF_S_JMP_JSET_K: |
| /* for conditionals both must be safe */ |
| if (pc + ftest->jt + 1 >= flen || |
| pc + ftest->jf + 1 >= flen) |
| return -EINVAL; |
| break; |
| case BPF_S_LD_W_ABS: |
| case BPF_S_LD_H_ABS: |
| case BPF_S_LD_B_ABS: |
| anc_found = false; |
| #define ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \ |
| code = BPF_S_ANC_##CODE; \ |
| anc_found = true; \ |
| break |
| switch (ftest->k) { |
| ANCILLARY(PROTOCOL); |
| ANCILLARY(PKTTYPE); |
| ANCILLARY(IFINDEX); |
| ANCILLARY(NLATTR); |
| ANCILLARY(NLATTR_NEST); |
| ANCILLARY(MARK); |
| ANCILLARY(QUEUE); |
| ANCILLARY(HATYPE); |
| ANCILLARY(RXHASH); |
| ANCILLARY(CPU); |
| ANCILLARY(ALU_XOR_X); |
| ANCILLARY(VLAN_TAG); |
| ANCILLARY(VLAN_TAG_PRESENT); |
| ANCILLARY(PAY_OFFSET); |
| } |
| |
| /* ancillary operation unknown or unsupported */ |
| if (anc_found == false && ftest->k >= SKF_AD_OFF) |
| return -EINVAL; |
| } |
| ftest->code = code; |
| } |
| |
| /* last instruction must be a RET code */ |
| switch (filter[flen - 1].code) { |
| case BPF_S_RET_K: |
| case BPF_S_RET_A: |
| return check_load_and_stores(filter, flen); |
| } |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL(sk_chk_filter); |
| |
| static int sk_store_orig_filter(struct sk_filter *fp, |
| const struct sock_fprog *fprog) |
| { |
| unsigned int fsize = sk_filter_proglen(fprog); |
| struct sock_fprog_kern *fkprog; |
| |
| fp->orig_prog = kmalloc(sizeof(*fkprog), GFP_KERNEL); |
| if (!fp->orig_prog) |
| return -ENOMEM; |
| |
| fkprog = fp->orig_prog; |
| fkprog->len = fprog->len; |
| fkprog->filter = kmemdup(fp->insns, fsize, GFP_KERNEL); |
| if (!fkprog->filter) { |
| kfree(fp->orig_prog); |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| static void sk_release_orig_filter(struct sk_filter *fp) |
| { |
| struct sock_fprog_kern *fprog = fp->orig_prog; |
| |
| if (fprog) { |
| kfree(fprog->filter); |
| kfree(fprog); |
| } |
| } |
| |
| /** |
| * sk_filter_release_rcu - Release a socket filter by rcu_head |
| * @rcu: rcu_head that contains the sk_filter to free |
| */ |
| static void sk_filter_release_rcu(struct rcu_head *rcu) |
| { |
| struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); |
| |
| sk_release_orig_filter(fp); |
| bpf_jit_free(fp); |
| } |
| |
| /** |
| * sk_filter_release - release a socket filter |
| * @fp: filter to remove |
| * |
| * Remove a filter from a socket and release its resources. |
| */ |
| static void sk_filter_release(struct sk_filter *fp) |
| { |
| if (atomic_dec_and_test(&fp->refcnt)) |
| call_rcu(&fp->rcu, sk_filter_release_rcu); |
| } |
| |
| void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp) |
| { |
| atomic_sub(sk_filter_size(fp->len), &sk->sk_omem_alloc); |
| sk_filter_release(fp); |
| } |
| |
| void sk_filter_charge(struct sock *sk, struct sk_filter *fp) |
| { |
| atomic_inc(&fp->refcnt); |
| atomic_add(sk_filter_size(fp->len), &sk->sk_omem_alloc); |
| } |
| |
| static struct sk_filter *__sk_migrate_realloc(struct sk_filter *fp, |
| struct sock *sk, |
| unsigned int len) |
| { |
| struct sk_filter *fp_new; |
| |
| if (sk == NULL) |
| return krealloc(fp, len, GFP_KERNEL); |
| |
| fp_new = sock_kmalloc(sk, len, GFP_KERNEL); |
| if (fp_new) { |
| memcpy(fp_new, fp, sizeof(struct sk_filter)); |
| /* As we're kepping orig_prog in fp_new along, |
| * we need to make sure we're not evicting it |
| * from the old fp. |
| */ |
| fp->orig_prog = NULL; |
| sk_filter_uncharge(sk, fp); |
| } |
| |
| return fp_new; |
| } |
| |
| static struct sk_filter *__sk_migrate_filter(struct sk_filter *fp, |
| struct sock *sk) |
| { |
| struct sock_filter *old_prog; |
| struct sk_filter *old_fp; |
| int i, err, new_len, old_len = fp->len; |
| |
| /* We are free to overwrite insns et al right here as it |
| * won't be used at this point in time anymore internally |
| * after the migration to the internal BPF instruction |
| * representation. |
| */ |
| BUILD_BUG_ON(sizeof(struct sock_filter) != |
| sizeof(struct sock_filter_int)); |
| |
| /* For now, we need to unfiddle BPF_S_* identifiers in place. |
| * This can sooner or later on be subject to removal, e.g. when |
| * JITs have been converted. |
| */ |
| for (i = 0; i < fp->len; i++) |
| sk_decode_filter(&fp->insns[i], &fp->insns[i]); |
| |
| /* Conversion cannot happen on overlapping memory areas, |
| * so we need to keep the user BPF around until the 2nd |
| * pass. At this time, the user BPF is stored in fp->insns. |
| */ |
| old_prog = kmemdup(fp->insns, old_len * sizeof(struct sock_filter), |
| GFP_KERNEL); |
| if (!old_prog) { |
| err = -ENOMEM; |
| goto out_err; |
| } |
| |
| /* 1st pass: calculate the new program length. */ |
| err = sk_convert_filter(old_prog, old_len, NULL, &new_len); |
| if (err) |
| goto out_err_free; |
| |
| /* Expand fp for appending the new filter representation. */ |
| old_fp = fp; |
| fp = __sk_migrate_realloc(old_fp, sk, sk_filter_size(new_len)); |
| if (!fp) { |
| /* The old_fp is still around in case we couldn't |
| * allocate new memory, so uncharge on that one. |
| */ |
| fp = old_fp; |
| err = -ENOMEM; |
| goto out_err_free; |
| } |
| |
| fp->bpf_func = sk_run_filter_int_skb; |
| fp->len = new_len; |
| |
| /* 2nd pass: remap sock_filter insns into sock_filter_int insns. */ |
| err = sk_convert_filter(old_prog, old_len, fp->insnsi, &new_len); |
| if (err) |
| /* 2nd sk_convert_filter() can fail only if it fails |
| * to allocate memory, remapping must succeed. Note, |
| * that at this time old_fp has already been released |
| * by __sk_migrate_realloc(). |
| */ |
| goto out_err_free; |
| |
| kfree(old_prog); |
| return fp; |
| |
| out_err_free: |
| kfree(old_prog); |
| out_err: |
| /* Rollback filter setup. */ |
| if (sk != NULL) |
| sk_filter_uncharge(sk, fp); |
| else |
| kfree(fp); |
| return ERR_PTR(err); |
| } |
| |
| static struct sk_filter *__sk_prepare_filter(struct sk_filter *fp, |
| struct sock *sk) |
| { |
| int err; |
| |
| fp->bpf_func = NULL; |
| fp->jited = 0; |
| |
| err = sk_chk_filter(fp->insns, fp->len); |
| if (err) |
| return ERR_PTR(err); |
| |
| /* Probe if we can JIT compile the filter and if so, do |
| * the compilation of the filter. |
| */ |
| bpf_jit_compile(fp); |
| |
| /* JIT compiler couldn't process this filter, so do the |
| * internal BPF translation for the optimized interpreter. |
| */ |
| if (!fp->jited) |
| fp = __sk_migrate_filter(fp, sk); |
| |
| return fp; |
| } |
| |
| /** |
| * sk_unattached_filter_create - create an unattached filter |
| * @fprog: the filter program |
| * @pfp: the unattached filter that is created |
| * |
| * Create a filter independent of any socket. We first run some |
| * sanity checks on it to make sure it does not explode on us later. |
| * If an error occurs or there is insufficient memory for the filter |
| * a negative errno code is returned. On success the return is zero. |
| */ |
| int sk_unattached_filter_create(struct sk_filter **pfp, |
| struct sock_fprog *fprog) |
| { |
| unsigned int fsize = sk_filter_proglen(fprog); |
| struct sk_filter *fp; |
| |
| /* Make sure new filter is there and in the right amounts. */ |
| if (fprog->filter == NULL) |
| return -EINVAL; |
| |
| fp = kmalloc(sk_filter_size(fprog->len), GFP_KERNEL); |
| if (!fp) |
| return -ENOMEM; |
| |
| memcpy(fp->insns, fprog->filter, fsize); |
| |
| atomic_set(&fp->refcnt, 1); |
| fp->len = fprog->len; |
| /* Since unattached filters are not copied back to user |
| * space through sk_get_filter(), we do not need to hold |
| * a copy here, and can spare us the work. |
| */ |
| fp->orig_prog = NULL; |
| |
| /* __sk_prepare_filter() already takes care of uncharging |
| * memory in case something goes wrong. |
| */ |
| fp = __sk_prepare_filter(fp, NULL); |
| if (IS_ERR(fp)) |
| return PTR_ERR(fp); |
| |
| *pfp = fp; |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(sk_unattached_filter_create); |
| |
| void sk_unattached_filter_destroy(struct sk_filter *fp) |
| { |
| sk_filter_release(fp); |
| } |
| EXPORT_SYMBOL_GPL(sk_unattached_filter_destroy); |
| |
| /** |
| * sk_attach_filter - attach a socket filter |
| * @fprog: the filter program |
| * @sk: the socket to use |
| * |
| * Attach the user's filter code. We first run some sanity checks on |
| * it to make sure it does not explode on us later. If an error |
| * occurs or there is insufficient memory for the filter a negative |
| * errno code is returned. On success the return is zero. |
| */ |
| int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) |
| { |
| struct sk_filter *fp, *old_fp; |
| unsigned int fsize = sk_filter_proglen(fprog); |
| unsigned int sk_fsize = sk_filter_size(fprog->len); |
| int err; |
| |
| if (sock_flag(sk, SOCK_FILTER_LOCKED)) |
| return -EPERM; |
| |
| /* Make sure new filter is there and in the right amounts. */ |
| if (fprog->filter == NULL) |
| return -EINVAL; |
| |
| fp = sock_kmalloc(sk, sk_fsize, GFP_KERNEL); |
| if (!fp) |
| return -ENOMEM; |
| |
| if (copy_from_user(fp->insns, fprog->filter, fsize)) { |
| sock_kfree_s(sk, fp, sk_fsize); |
| return -EFAULT; |
| } |
| |
| atomic_set(&fp->refcnt, 1); |
| fp->len = fprog->len; |
| |
| err = sk_store_orig_filter(fp, fprog); |
| if (err) { |
| sk_filter_uncharge(sk, fp); |
| return -ENOMEM; |
| } |
| |
| /* __sk_prepare_filter() already takes care of uncharging |
| * memory in case something goes wrong. |
| */ |
| fp = __sk_prepare_filter(fp, sk); |
| if (IS_ERR(fp)) |
| return PTR_ERR(fp); |
| |
| old_fp = rcu_dereference_protected(sk->sk_filter, |
| sock_owned_by_user(sk)); |
| rcu_assign_pointer(sk->sk_filter, fp); |
| |
| if (old_fp) |
| sk_filter_uncharge(sk, old_fp); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(sk_attach_filter); |
| |
| int sk_detach_filter(struct sock *sk) |
| { |
| int ret = -ENOENT; |
| struct sk_filter *filter; |
| |
| if (sock_flag(sk, SOCK_FILTER_LOCKED)) |
| return -EPERM; |
| |
| filter = rcu_dereference_protected(sk->sk_filter, |
| sock_owned_by_user(sk)); |
| if (filter) { |
| RCU_INIT_POINTER(sk->sk_filter, NULL); |
| sk_filter_uncharge(sk, filter); |
| ret = 0; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(sk_detach_filter); |
| |
| void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to) |
| { |
| static const u16 decodes[] = { |
| [BPF_S_ALU_ADD_K] = BPF_ALU|BPF_ADD|BPF_K, |
| [BPF_S_ALU_ADD_X] = BPF_ALU|BPF_ADD|BPF_X, |
| [BPF_S_ALU_SUB_K] = BPF_ALU|BPF_SUB|BPF_K, |
| [BPF_S_ALU_SUB_X] = BPF_ALU|BPF_SUB|BPF_X, |
| [BPF_S_ALU_MUL_K] = BPF_ALU|BPF_MUL|BPF_K, |
| [BPF_S_ALU_MUL_X] = BPF_ALU|BPF_MUL|BPF_X, |
| [BPF_S_ALU_DIV_X] = BPF_ALU|BPF_DIV|BPF_X, |
| [BPF_S_ALU_MOD_K] = BPF_ALU|BPF_MOD|BPF_K, |
| [BPF_S_ALU_MOD_X] = BPF_ALU|BPF_MOD|BPF_X, |
| [BPF_S_ALU_AND_K] = BPF_ALU|BPF_AND|BPF_K, |
| [BPF_S_ALU_AND_X] = BPF_ALU|BPF_AND|BPF_X, |
| [BPF_S_ALU_OR_K] = BPF_ALU|BPF_OR|BPF_K, |
| [BPF_S_ALU_OR_X] = BPF_ALU|BPF_OR|BPF_X, |
| [BPF_S_ALU_XOR_K] = BPF_ALU|BPF_XOR|BPF_K, |
| [BPF_S_ALU_XOR_X] = BPF_ALU|BPF_XOR|BPF_X, |
| [BPF_S_ALU_LSH_K] = BPF_ALU|BPF_LSH|BPF_K, |
| [BPF_S_ALU_LSH_X] = BPF_ALU|BPF_LSH|BPF_X, |
| [BPF_S_ALU_RSH_K] = BPF_ALU|BPF_RSH|BPF_K, |
| [BPF_S_ALU_RSH_X] = BPF_ALU|BPF_RSH|BPF_X, |
| [BPF_S_ALU_NEG] = BPF_ALU|BPF_NEG, |
| [BPF_S_LD_W_ABS] = BPF_LD|BPF_W|BPF_ABS, |
| [BPF_S_LD_H_ABS] = BPF_LD|BPF_H|BPF_ABS, |
| [BPF_S_LD_B_ABS] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_PROTOCOL] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_PKTTYPE] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_IFINDEX] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_NLATTR] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_NLATTR_NEST] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_MARK] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_QUEUE] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_HATYPE] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_RXHASH] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_CPU] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_ALU_XOR_X] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_VLAN_TAG] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_VLAN_TAG_PRESENT] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_ANC_PAY_OFFSET] = BPF_LD|BPF_B|BPF_ABS, |
| [BPF_S_LD_W_LEN] = BPF_LD|BPF_W|BPF_LEN, |
| [BPF_S_LD_W_IND] = BPF_LD|BPF_W|BPF_IND, |
| [BPF_S_LD_H_IND] = BPF_LD|BPF_H|BPF_IND, |
| [BPF_S_LD_B_IND] = BPF_LD|BPF_B|BPF_IND, |
| [BPF_S_LD_IMM] = BPF_LD|BPF_IMM, |
| [BPF_S_LDX_W_LEN] = BPF_LDX|BPF_W|BPF_LEN, |
| [BPF_S_LDX_B_MSH] = BPF_LDX|BPF_B|BPF_MSH, |
| [BPF_S_LDX_IMM] = BPF_LDX|BPF_IMM, |
| [BPF_S_MISC_TAX] = BPF_MISC|BPF_TAX, |
| [BPF_S_MISC_TXA] = BPF_MISC|BPF_TXA, |
| [BPF_S_RET_K] = BPF_RET|BPF_K, |
| [BPF_S_RET_A] = BPF_RET|BPF_A, |
| [BPF_S_ALU_DIV_K] = BPF_ALU|BPF_DIV|BPF_K, |
| [BPF_S_LD_MEM] = BPF_LD|BPF_MEM, |
| [BPF_S_LDX_MEM] = BPF_LDX|BPF_MEM, |
| [BPF_S_ST] = BPF_ST, |
| [BPF_S_STX] = BPF_STX, |
| [BPF_S_JMP_JA] = BPF_JMP|BPF_JA, |
| [BPF_S_JMP_JEQ_K] = BPF_JMP|BPF_JEQ|BPF_K, |
| [BPF_S_JMP_JEQ_X] = BPF_JMP|BPF_JEQ|BPF_X, |
| [BPF_S_JMP_JGE_K] = BPF_JMP|BPF_JGE|BPF_K, |
| [BPF_S_JMP_JGE_X] = BPF_JMP|BPF_JGE|BPF_X, |
| [BPF_S_JMP_JGT_K] = BPF_JMP|BPF_JGT|BPF_K, |
| [BPF_S_JMP_JGT_X] = BPF_JMP|BPF_JGT|BPF_X, |
| [BPF_S_JMP_JSET_K] = BPF_JMP|BPF_JSET|BPF_K, |
| [BPF_S_JMP_JSET_X] = BPF_JMP|BPF_JSET|BPF_X, |
| }; |
| u16 code; |
| |
| code = filt->code; |
| |
| to->code = decodes[code]; |
| to->jt = filt->jt; |
| to->jf = filt->jf; |
| to->k = filt->k; |
| } |
| |
| int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf, |
| unsigned int len) |
| { |
| struct sock_fprog_kern *fprog; |
| struct sk_filter *filter; |
| int ret = 0; |
| |
| lock_sock(sk); |
| filter = rcu_dereference_protected(sk->sk_filter, |
| sock_owned_by_user(sk)); |
| if (!filter) |
| goto out; |
| |
| /* We're copying the filter that has been originally attached, |
| * so no conversion/decode needed anymore. |
| */ |
| fprog = filter->orig_prog; |
| |
| ret = fprog->len; |
| if (!len) |
| /* User space only enquires number of filter blocks. */ |
| goto out; |
| |
| ret = -EINVAL; |
| if (len < fprog->len) |
| goto out; |
| |
| ret = -EFAULT; |
| if (copy_to_user(ubuf, fprog->filter, sk_filter_proglen(fprog))) |
| goto out; |
| |
| /* Instead of bytes, the API requests to return the number |
| * of filter blocks. |
| */ |
| ret = fprog->len; |
| out: |
| release_sock(sk); |
| return ret; |
| } |