667 lines
17 KiB
C
667 lines
17 KiB
C
/*
|
|
* 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 bpf_check_classic()
|
|
*/
|
|
|
|
#include <linux/filter.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/random.h>
|
|
#include <linux/moduleloader.h>
|
|
#include <asm/unaligned.h>
|
|
#include <linux/bpf.h>
|
|
|
|
/* Registers */
|
|
#define BPF_R0 regs[BPF_REG_0]
|
|
#define BPF_R1 regs[BPF_REG_1]
|
|
#define BPF_R2 regs[BPF_REG_2]
|
|
#define BPF_R3 regs[BPF_REG_3]
|
|
#define BPF_R4 regs[BPF_REG_4]
|
|
#define BPF_R5 regs[BPF_REG_5]
|
|
#define BPF_R6 regs[BPF_REG_6]
|
|
#define BPF_R7 regs[BPF_REG_7]
|
|
#define BPF_R8 regs[BPF_REG_8]
|
|
#define BPF_R9 regs[BPF_REG_9]
|
|
#define BPF_R10 regs[BPF_REG_10]
|
|
|
|
/* Named registers */
|
|
#define DST regs[insn->dst_reg]
|
|
#define SRC regs[insn->src_reg]
|
|
#define FP regs[BPF_REG_FP]
|
|
#define ARG1 regs[BPF_REG_ARG1]
|
|
#define CTX regs[BPF_REG_CTX]
|
|
#define IMM insn->imm
|
|
|
|
/* 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;
|
|
}
|
|
|
|
struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
|
|
{
|
|
gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
|
|
gfp_extra_flags;
|
|
struct bpf_prog_aux *aux;
|
|
struct bpf_prog *fp;
|
|
|
|
size = round_up(size, PAGE_SIZE);
|
|
fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
|
|
if (fp == NULL)
|
|
return NULL;
|
|
|
|
aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
|
|
if (aux == NULL) {
|
|
vfree(fp);
|
|
return NULL;
|
|
}
|
|
|
|
fp->pages = size / PAGE_SIZE;
|
|
fp->aux = aux;
|
|
|
|
return fp;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_prog_alloc);
|
|
|
|
struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
|
|
gfp_t gfp_extra_flags)
|
|
{
|
|
gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
|
|
gfp_extra_flags;
|
|
struct bpf_prog *fp;
|
|
|
|
BUG_ON(fp_old == NULL);
|
|
|
|
size = round_up(size, PAGE_SIZE);
|
|
if (size <= fp_old->pages * PAGE_SIZE)
|
|
return fp_old;
|
|
|
|
fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
|
|
if (fp != NULL) {
|
|
memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
|
|
fp->pages = size / PAGE_SIZE;
|
|
|
|
/* We keep fp->aux from fp_old around in the new
|
|
* reallocated structure.
|
|
*/
|
|
fp_old->aux = NULL;
|
|
__bpf_prog_free(fp_old);
|
|
}
|
|
|
|
return fp;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_prog_realloc);
|
|
|
|
void __bpf_prog_free(struct bpf_prog *fp)
|
|
{
|
|
kfree(fp->aux);
|
|
vfree(fp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__bpf_prog_free);
|
|
|
|
#ifdef CONFIG_BPF_JIT
|
|
struct bpf_binary_header *
|
|
bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
|
|
unsigned int alignment,
|
|
bpf_jit_fill_hole_t bpf_fill_ill_insns)
|
|
{
|
|
struct bpf_binary_header *hdr;
|
|
unsigned int size, hole, start;
|
|
|
|
/* Most of BPF filters are really small, but if some of them
|
|
* fill a page, allow at least 128 extra bytes to insert a
|
|
* random section of illegal instructions.
|
|
*/
|
|
size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
|
|
hdr = module_alloc(size);
|
|
if (hdr == NULL)
|
|
return NULL;
|
|
|
|
/* Fill space with illegal/arch-dep instructions. */
|
|
bpf_fill_ill_insns(hdr, size);
|
|
|
|
hdr->pages = size / PAGE_SIZE;
|
|
hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
|
|
PAGE_SIZE - sizeof(*hdr));
|
|
start = (prandom_u32() % hole) & ~(alignment - 1);
|
|
|
|
/* Leave a random number of instructions before BPF code. */
|
|
*image_ptr = &hdr->image[start];
|
|
|
|
return hdr;
|
|
}
|
|
|
|
void bpf_jit_binary_free(struct bpf_binary_header *hdr)
|
|
{
|
|
module_free(NULL, hdr);
|
|
}
|
|
#endif /* CONFIG_BPF_JIT */
|
|
|
|
/* 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;
|
|
}
|
|
|
|
/**
|
|
* __bpf_prog_run - run eBPF program on a given context
|
|
* @ctx: is the data we are operating on
|
|
* @insn: is the array of eBPF instructions
|
|
*
|
|
* Decode and execute eBPF instructions.
|
|
*/
|
|
static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
|
|
{
|
|
u64 stack[MAX_BPF_STACK / sizeof(u64)];
|
|
u64 regs[MAX_BPF_REG], tmp;
|
|
static const void *jumptable[256] = {
|
|
[0 ... 255] = &&default_label,
|
|
/* Now overwrite non-defaults ... */
|
|
/* 32 bit ALU operations */
|
|
[BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
|
|
[BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
|
|
[BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
|
|
[BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
|
|
[BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
|
|
[BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
|
|
[BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X,
|
|
[BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K,
|
|
[BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
|
|
[BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
|
|
[BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
|
|
[BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
|
|
[BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
|
|
[BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
|
|
[BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
|
|
[BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
|
|
[BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
|
|
[BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
|
|
[BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
|
|
[BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
|
|
[BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
|
|
[BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
|
|
[BPF_ALU | BPF_NEG] = &&ALU_NEG,
|
|
[BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
|
|
[BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
|
|
/* 64 bit ALU operations */
|
|
[BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
|
|
[BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
|
|
[BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
|
|
[BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
|
|
[BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
|
|
[BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
|
|
[BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
|
|
[BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
|
|
[BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
|
|
[BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
|
|
[BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
|
|
[BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
|
|
[BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
|
|
[BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
|
|
[BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
|
|
[BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
|
|
[BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
|
|
[BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
|
|
[BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
|
|
[BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
|
|
[BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
|
|
[BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
|
|
[BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
|
|
[BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
|
|
[BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
|
|
/* Call instruction */
|
|
[BPF_JMP | BPF_CALL] = &&JMP_CALL,
|
|
/* Jumps */
|
|
[BPF_JMP | BPF_JA] = &&JMP_JA,
|
|
[BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
|
|
[BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
|
|
[BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
|
|
[BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
|
|
[BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
|
|
[BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
|
|
[BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
|
|
[BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
|
|
[BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
|
|
[BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
|
|
[BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
|
|
[BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
|
|
[BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
|
|
[BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
|
|
/* Program return */
|
|
[BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
|
|
/* Store instructions */
|
|
[BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
|
|
[BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
|
|
[BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
|
|
[BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
|
|
[BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
|
|
[BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
|
|
[BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
|
|
[BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
|
|
[BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
|
|
[BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
|
|
/* Load instructions */
|
|
[BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
|
|
[BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
|
|
[BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
|
|
[BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
|
|
[BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
|
|
[BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
|
|
[BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
|
|
[BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
|
|
[BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
|
|
[BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
|
|
[BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
|
|
};
|
|
void *ptr;
|
|
int off;
|
|
|
|
#define CONT ({ insn++; goto select_insn; })
|
|
#define CONT_JMP ({ insn++; goto select_insn; })
|
|
|
|
FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
|
|
ARG1 = (u64) (unsigned long) ctx;
|
|
|
|
/* Registers used in classic BPF programs need to be reset first. */
|
|
regs[BPF_REG_A] = 0;
|
|
regs[BPF_REG_X] = 0;
|
|
|
|
select_insn:
|
|
goto *jumptable[insn->code];
|
|
|
|
/* ALU */
|
|
#define ALU(OPCODE, OP) \
|
|
ALU64_##OPCODE##_X: \
|
|
DST = DST OP SRC; \
|
|
CONT; \
|
|
ALU_##OPCODE##_X: \
|
|
DST = (u32) DST OP (u32) SRC; \
|
|
CONT; \
|
|
ALU64_##OPCODE##_K: \
|
|
DST = DST OP IMM; \
|
|
CONT; \
|
|
ALU_##OPCODE##_K: \
|
|
DST = (u32) DST OP (u32) IMM; \
|
|
CONT;
|
|
|
|
ALU(ADD, +)
|
|
ALU(SUB, -)
|
|
ALU(AND, &)
|
|
ALU(OR, |)
|
|
ALU(LSH, <<)
|
|
ALU(RSH, >>)
|
|
ALU(XOR, ^)
|
|
ALU(MUL, *)
|
|
#undef ALU
|
|
ALU_NEG:
|
|
DST = (u32) -DST;
|
|
CONT;
|
|
ALU64_NEG:
|
|
DST = -DST;
|
|
CONT;
|
|
ALU_MOV_X:
|
|
DST = (u32) SRC;
|
|
CONT;
|
|
ALU_MOV_K:
|
|
DST = (u32) IMM;
|
|
CONT;
|
|
ALU64_MOV_X:
|
|
DST = SRC;
|
|
CONT;
|
|
ALU64_MOV_K:
|
|
DST = IMM;
|
|
CONT;
|
|
LD_IMM_DW:
|
|
DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
|
|
insn++;
|
|
CONT;
|
|
ALU64_ARSH_X:
|
|
(*(s64 *) &DST) >>= SRC;
|
|
CONT;
|
|
ALU64_ARSH_K:
|
|
(*(s64 *) &DST) >>= IMM;
|
|
CONT;
|
|
ALU64_MOD_X:
|
|
if (unlikely(SRC == 0))
|
|
return 0;
|
|
tmp = DST;
|
|
DST = do_div(tmp, SRC);
|
|
CONT;
|
|
ALU_MOD_X:
|
|
if (unlikely(SRC == 0))
|
|
return 0;
|
|
tmp = (u32) DST;
|
|
DST = do_div(tmp, (u32) SRC);
|
|
CONT;
|
|
ALU64_MOD_K:
|
|
tmp = DST;
|
|
DST = do_div(tmp, IMM);
|
|
CONT;
|
|
ALU_MOD_K:
|
|
tmp = (u32) DST;
|
|
DST = do_div(tmp, (u32) IMM);
|
|
CONT;
|
|
ALU64_DIV_X:
|
|
if (unlikely(SRC == 0))
|
|
return 0;
|
|
do_div(DST, SRC);
|
|
CONT;
|
|
ALU_DIV_X:
|
|
if (unlikely(SRC == 0))
|
|
return 0;
|
|
tmp = (u32) DST;
|
|
do_div(tmp, (u32) SRC);
|
|
DST = (u32) tmp;
|
|
CONT;
|
|
ALU64_DIV_K:
|
|
do_div(DST, IMM);
|
|
CONT;
|
|
ALU_DIV_K:
|
|
tmp = (u32) DST;
|
|
do_div(tmp, (u32) IMM);
|
|
DST = (u32) tmp;
|
|
CONT;
|
|
ALU_END_TO_BE:
|
|
switch (IMM) {
|
|
case 16:
|
|
DST = (__force u16) cpu_to_be16(DST);
|
|
break;
|
|
case 32:
|
|
DST = (__force u32) cpu_to_be32(DST);
|
|
break;
|
|
case 64:
|
|
DST = (__force u64) cpu_to_be64(DST);
|
|
break;
|
|
}
|
|
CONT;
|
|
ALU_END_TO_LE:
|
|
switch (IMM) {
|
|
case 16:
|
|
DST = (__force u16) cpu_to_le16(DST);
|
|
break;
|
|
case 32:
|
|
DST = (__force u32) cpu_to_le32(DST);
|
|
break;
|
|
case 64:
|
|
DST = (__force u64) cpu_to_le64(DST);
|
|
break;
|
|
}
|
|
CONT;
|
|
|
|
/* CALL */
|
|
JMP_CALL:
|
|
/* Function call scratches BPF_R1-BPF_R5 registers,
|
|
* preserves BPF_R6-BPF_R9, and stores return value
|
|
* into BPF_R0.
|
|
*/
|
|
BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
|
|
BPF_R4, BPF_R5);
|
|
CONT;
|
|
|
|
/* JMP */
|
|
JMP_JA:
|
|
insn += insn->off;
|
|
CONT;
|
|
JMP_JEQ_X:
|
|
if (DST == SRC) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JEQ_K:
|
|
if (DST == IMM) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JNE_X:
|
|
if (DST != SRC) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JNE_K:
|
|
if (DST != IMM) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JGT_X:
|
|
if (DST > SRC) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JGT_K:
|
|
if (DST > IMM) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JGE_X:
|
|
if (DST >= SRC) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JGE_K:
|
|
if (DST >= IMM) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JSGT_X:
|
|
if (((s64) DST) > ((s64) SRC)) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JSGT_K:
|
|
if (((s64) DST) > ((s64) IMM)) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JSGE_X:
|
|
if (((s64) DST) >= ((s64) SRC)) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JSGE_K:
|
|
if (((s64) DST) >= ((s64) IMM)) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JSET_X:
|
|
if (DST & SRC) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_JSET_K:
|
|
if (DST & IMM) {
|
|
insn += insn->off;
|
|
CONT_JMP;
|
|
}
|
|
CONT;
|
|
JMP_EXIT:
|
|
return BPF_R0;
|
|
|
|
/* STX and ST and LDX*/
|
|
#define LDST(SIZEOP, SIZE) \
|
|
STX_MEM_##SIZEOP: \
|
|
*(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
|
|
CONT; \
|
|
ST_MEM_##SIZEOP: \
|
|
*(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
|
|
CONT; \
|
|
LDX_MEM_##SIZEOP: \
|
|
DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
|
|
CONT;
|
|
|
|
LDST(B, u8)
|
|
LDST(H, u16)
|
|
LDST(W, u32)
|
|
LDST(DW, u64)
|
|
#undef LDST
|
|
STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
|
|
atomic_add((u32) SRC, (atomic_t *)(unsigned long)
|
|
(DST + insn->off));
|
|
CONT;
|
|
STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
|
|
atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
|
|
(DST + insn->off));
|
|
CONT;
|
|
LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
|
|
off = IMM;
|
|
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[BPF_REG_CTX]
|
|
* == BPF_R6, bpf_convert_filter() saves it in BPF_R6,
|
|
* internal BPF verifier will check that BPF_R6 ==
|
|
* ctx.
|
|
*
|
|
* BPF_ABS and BPF_IND are wrappers of function calls,
|
|
* so they scratch BPF_R1-BPF_R5 registers, preserve
|
|
* BPF_R6-BPF_R9, and store return value into BPF_R0.
|
|
*
|
|
* Implicit input:
|
|
* ctx == skb == BPF_R6 == CTX
|
|
*
|
|
* Explicit input:
|
|
* SRC == any register
|
|
* IMM == 32-bit immediate
|
|
*
|
|
* Output:
|
|
* BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
|
|
*/
|
|
|
|
ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
|
|
if (likely(ptr != NULL)) {
|
|
BPF_R0 = get_unaligned_be32(ptr);
|
|
CONT;
|
|
}
|
|
|
|
return 0;
|
|
LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
|
|
off = IMM;
|
|
load_half:
|
|
ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
|
|
if (likely(ptr != NULL)) {
|
|
BPF_R0 = get_unaligned_be16(ptr);
|
|
CONT;
|
|
}
|
|
|
|
return 0;
|
|
LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
|
|
off = IMM;
|
|
load_byte:
|
|
ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
|
|
if (likely(ptr != NULL)) {
|
|
BPF_R0 = *(u8 *)ptr;
|
|
CONT;
|
|
}
|
|
|
|
return 0;
|
|
LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
|
|
off = IMM + SRC;
|
|
goto load_word;
|
|
LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
|
|
off = IMM + SRC;
|
|
goto load_half;
|
|
LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
|
|
off = IMM + SRC;
|
|
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;
|
|
}
|
|
|
|
void __weak bpf_int_jit_compile(struct bpf_prog *prog)
|
|
{
|
|
}
|
|
|
|
/**
|
|
* bpf_prog_select_runtime - select execution runtime for BPF program
|
|
* @fp: bpf_prog populated with internal BPF program
|
|
*
|
|
* try to JIT internal BPF program, if JIT is not available select interpreter
|
|
* BPF program will be executed via BPF_PROG_RUN() macro
|
|
*/
|
|
void bpf_prog_select_runtime(struct bpf_prog *fp)
|
|
{
|
|
fp->bpf_func = (void *) __bpf_prog_run;
|
|
|
|
/* Probe if internal BPF can be JITed */
|
|
bpf_int_jit_compile(fp);
|
|
/* Lock whole bpf_prog as read-only */
|
|
bpf_prog_lock_ro(fp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
|
|
|
|
static void bpf_prog_free_deferred(struct work_struct *work)
|
|
{
|
|
struct bpf_prog_aux *aux;
|
|
|
|
aux = container_of(work, struct bpf_prog_aux, work);
|
|
bpf_jit_free(aux->prog);
|
|
}
|
|
|
|
/* Free internal BPF program */
|
|
void bpf_prog_free(struct bpf_prog *fp)
|
|
{
|
|
struct bpf_prog_aux *aux = fp->aux;
|
|
|
|
INIT_WORK(&aux->work, bpf_prog_free_deferred);
|
|
aux->prog = fp;
|
|
schedule_work(&aux->work);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_prog_free);
|
|
|
|
/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
|
|
* skb_copy_bits(), so provide a weak definition of it for NET-less config.
|
|
*/
|
|
int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
|
|
int len)
|
|
{
|
|
return -EFAULT;
|
|
}
|