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ubpf_vm.c
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ubpf_vm.c
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// Copyright (c) 2015 Big Switch Networks, Inc
// SPDX-License-Identifier: Apache-2.0
/*
* Copyright 2015 Big Switch Networks, Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define _GNU_SOURCE
#include "ubpf.h"
#include "ebpf.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdarg.h>
#include <sys/mman.h>
#include <endian.h>
#include "ubpf_int.h"
#include <unistd.h>
#define MAX_EXT_FUNCS 64
#define SHIFT_MASK_32_BIT(X) ((X) & 0x1f)
#define SHIFT_MASK_64_BIT(X) ((X) & 0x3f)
static bool
validate(const struct ubpf_vm* vm, const struct ebpf_inst* insts, uint32_t num_insts, char** errmsg);
static bool
bounds_check(
const struct ubpf_vm* vm,
void* addr,
int size,
const char* type,
uint16_t cur_pc,
void* mem,
size_t mem_len,
void* stack);
bool
ubpf_toggle_bounds_check(struct ubpf_vm* vm, bool enable)
{
bool old = vm->bounds_check_enabled;
vm->bounds_check_enabled = enable;
return old;
}
void
ubpf_set_error_print(struct ubpf_vm* vm, int (*error_printf)(FILE* stream, const char* format, ...))
{
if (error_printf)
vm->error_printf = error_printf;
else
vm->error_printf = fprintf;
}
struct ubpf_vm*
ubpf_create(void)
{
struct ubpf_vm* vm = calloc(1, sizeof(*vm));
if (vm == NULL) {
return NULL;
}
vm->ext_funcs = calloc(MAX_EXT_FUNCS, sizeof(*vm->ext_funcs));
if (vm->ext_funcs == NULL) {
ubpf_destroy(vm);
return NULL;
}
vm->ext_func_names = calloc(MAX_EXT_FUNCS, sizeof(*vm->ext_func_names));
if (vm->ext_func_names == NULL) {
ubpf_destroy(vm);
return NULL;
}
vm->bounds_check_enabled = true;
vm->error_printf = fprintf;
#if defined(__x86_64__) || defined(_M_X64)
vm->translate = ubpf_translate_x86_64;
#elif defined(__aarch64__) || defined(_M_ARM64)
vm->translate = ubpf_translate_arm64;
#else
vm->translate = ubpf_translate_null;
#endif
vm->unwind_stack_extension_index = -1;
return vm;
}
void
ubpf_destroy(struct ubpf_vm* vm)
{
ubpf_unload_code(vm);
free(vm->int_funcs);
free(vm->ext_funcs);
free(vm->ext_func_names);
free(vm);
}
external_function_t
as_external_function_t(void* f)
{
return (external_function_t)f;
};
int
ubpf_register(struct ubpf_vm* vm, unsigned int idx, const char* name, external_function_t fn)
{
if (vm->dispatcher != NULL) {
return -1;
}
if (idx >= MAX_EXT_FUNCS) {
return -1;
}
vm->ext_funcs[idx] = (ext_func)fn;
vm->ext_func_names[idx] = name;
return 0;
}
int
ubpf_register_external_dispatcher(
struct ubpf_vm* vm, external_function_dispatcher_t dispatcher, external_function_validate_t validater, void* cookie)
{
vm->dispatcher = dispatcher;
vm->dispatcher_validate = validater;
vm->dispatcher_cookie = cookie;
return 0;
}
int
ubpf_set_unwind_function_index(struct ubpf_vm* vm, unsigned int idx)
{
if (vm->unwind_stack_extension_index != -1) {
return -1;
}
vm->unwind_stack_extension_index = idx;
return 0;
}
unsigned int
ubpf_lookup_registered_function(struct ubpf_vm* vm, const char* name)
{
int i;
for (i = 0; i < MAX_EXT_FUNCS; i++) {
const char* other = vm->ext_func_names[i];
if (other && !strcmp(other, name)) {
return i;
}
}
return -1;
}
bool
ubpf_validate_external_helper(const struct ubpf_vm* vm, unsigned int idx)
{
if (vm->dispatcher_validate) {
return vm->dispatcher_validate(idx, vm->dispatcher_cookie);
}
return vm->ext_funcs[idx] != NULL;
}
uint64_t
ubpf_dispatch_to_external_helper(
uint64_t p0, uint64_t p1, uint64_t p2, uint64_t p3, uint64_t p4, const struct ubpf_vm* vm, unsigned int idx)
{
if (vm->dispatcher != NULL) {
return vm->dispatcher(vm->dispatcher_cookie, idx, p0, p1, p2, p3, p4);
}
if (vm->ext_funcs[idx] != NULL) {
return vm->ext_funcs[idx](p0, p1, p2, p3, p4);
}
return -1;
}
int
ubpf_load(struct ubpf_vm* vm, const void* code, uint32_t code_len, char** errmsg)
{
const struct ebpf_inst* source_inst = code;
*errmsg = NULL;
if (UBPF_STACK_SIZE % sizeof(uint64_t) != 0) {
*errmsg = ubpf_error("UBPF_STACK_SIZE must be a multiple of 8");
return -1;
}
if (vm->insts) {
*errmsg = ubpf_error(
"code has already been loaded into this VM. Use ubpf_unload_code() if you need to reuse this VM");
return -1;
}
if (code_len % 8 != 0) {
*errmsg = ubpf_error("code_len must be a multiple of 8");
return -1;
}
if (!validate(vm, code, code_len / 8, errmsg)) {
return -1;
}
vm->insts = malloc(code_len);
if (vm->insts == NULL) {
*errmsg = ubpf_error("out of memory");
return -1;
}
vm->num_insts = code_len / sizeof(vm->insts[0]);
vm->int_funcs = (bool*)calloc(vm->num_insts, sizeof(bool));
if (!vm->int_funcs) {
*errmsg = ubpf_error("out of memory");
return -1;
}
for (uint32_t i = 0; i < vm->num_insts; i++) {
/* Mark targets of local call instructions. They
* represent the beginning of local functions and
* the jitter may need to do something special with
* them.
*/
if (source_inst[i].opcode == EBPF_OP_CALL && source_inst[i].src == 1) {
uint32_t target = i + source_inst[i].imm + 1;
vm->int_funcs[target] = true;
}
// Store instructions in the vm.
ubpf_store_instruction(vm, i, source_inst[i]);
}
return 0;
}
void
ubpf_unload_code(struct ubpf_vm* vm)
{
if (vm->jitted) {
munmap(vm->jitted, vm->jitted_size);
vm->jitted = NULL;
vm->jitted_size = 0;
}
if (vm->insts) {
free(vm->insts);
vm->insts = NULL;
vm->num_insts = 0;
}
}
static uint32_t
u32(uint64_t x)
{
return x;
}
static int32_t
i32(uint64_t x)
{
return x;
}
#define IS_ALIGNED(x, a) (((uintptr_t)(x) & ((a)-1)) == 0)
inline static uint64_t
ubpf_mem_load(uint64_t address, size_t size)
{
if (!IS_ALIGNED(address, size)) {
// Fill the result with 0 to avoid leaking uninitialized memory.
uint64_t value = 0;
memcpy(&value, (void*)address, size);
return value;
}
switch (size) {
case 1:
return *(uint8_t*)address;
case 2:
return *(uint16_t*)address;
case 4:
return *(uint32_t*)address;
case 8:
return *(uint64_t*)address;
default:
abort();
}
}
inline static void
ubpf_mem_store(uint64_t address, uint64_t value, size_t size)
{
if (!IS_ALIGNED(address, size)) {
memcpy((void*)address, &value, size);
return;
}
switch (size) {
case 1:
*(uint8_t*)address = value;
break;
case 2:
*(uint16_t*)address = value;
break;
case 4:
*(uint32_t*)address = value;
break;
case 8:
*(uint64_t*)address = value;
break;
default:
abort();
}
}
int
ubpf_exec(const struct ubpf_vm* vm, void* mem, size_t mem_len, uint64_t* bpf_return_value)
{
uint16_t pc = 0;
const struct ebpf_inst* insts = vm->insts;
uint64_t* reg;
uint64_t _reg[16];
uint64_t ras_index = 0;
int return_value = -1;
// Windows Kernel mode limits stack usage to 12K, so we need to allocate it dynamically.
#if defined(NTDDI_VERSION) && defined(WINNT)
uint64_t* stack = NULL;
struct ubpf_stack_frame* stack_frames = NULL;
stack = calloc(UBPF_STACK_SIZE, 1);
if (!stack) {
return_value = -1;
goto cleanup;
}
stack_frames = calloc(UBPF_MAX_CALL_DEPTH, sizeof(struct ubpf_stack_frame));
if (!stack_frames) {
return_value = -1;
goto cleanup;
}
#else
uint64_t stack[UBPF_STACK_SIZE / sizeof(uint64_t)];
struct ubpf_stack_frame stack_frames[UBPF_MAX_CALL_DEPTH] = {
0,
};
#endif
if (!insts) {
/* Code must be loaded before we can execute */
return -1;
}
#ifdef DEBUG
if (vm->regs)
reg = vm->regs;
else
reg = _reg;
#else
reg = _reg;
#endif
reg[1] = (uintptr_t)mem;
reg[2] = (uint64_t)mem_len;
reg[10] = (uintptr_t)stack + UBPF_STACK_SIZE;
while (1) {
const uint16_t cur_pc = pc;
struct ebpf_inst inst = ubpf_fetch_instruction(vm, pc++);
switch (inst.opcode) {
case EBPF_OP_ADD_IMM:
reg[inst.dst] += inst.imm;
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_ADD_REG:
reg[inst.dst] += reg[inst.src];
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_SUB_IMM:
reg[inst.dst] -= inst.imm;
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_SUB_REG:
reg[inst.dst] -= reg[inst.src];
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_MUL_IMM:
reg[inst.dst] *= inst.imm;
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_MUL_REG:
reg[inst.dst] *= reg[inst.src];
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_DIV_IMM:
reg[inst.dst] = u32(inst.imm) ? u32(reg[inst.dst]) / u32(inst.imm) : 0;
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_DIV_REG:
reg[inst.dst] = u32(reg[inst.src]) ? u32(reg[inst.dst]) / u32(reg[inst.src]) : 0;
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_OR_IMM:
reg[inst.dst] |= inst.imm;
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_OR_REG:
reg[inst.dst] |= reg[inst.src];
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_AND_IMM:
reg[inst.dst] &= inst.imm;
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_AND_REG:
reg[inst.dst] &= reg[inst.src];
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_LSH_IMM:
reg[inst.dst] = (u32(reg[inst.dst]) << SHIFT_MASK_32_BIT(inst.imm) & UINT32_MAX);
break;
case EBPF_OP_LSH_REG:
reg[inst.dst] = (u32(reg[inst.dst]) << SHIFT_MASK_32_BIT(reg[inst.src]) & UINT32_MAX);
break;
case EBPF_OP_RSH_IMM:
reg[inst.dst] = u32(reg[inst.dst]) >> SHIFT_MASK_32_BIT(inst.imm);
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_RSH_REG:
reg[inst.dst] = u32(reg[inst.dst]) >> SHIFT_MASK_32_BIT(reg[inst.src]);
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_NEG:
reg[inst.dst] = -(int64_t)reg[inst.dst];
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_MOD_IMM:
reg[inst.dst] = u32(inst.imm) ? u32(reg[inst.dst]) % u32(inst.imm) : u32(reg[inst.dst]);
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_MOD_REG:
reg[inst.dst] = u32(reg[inst.src]) ? u32(reg[inst.dst]) % u32(reg[inst.src]) : u32(reg[inst.dst]);
break;
case EBPF_OP_XOR_IMM:
reg[inst.dst] ^= inst.imm;
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_XOR_REG:
reg[inst.dst] ^= reg[inst.src];
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_MOV_IMM:
reg[inst.dst] = inst.imm;
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_MOV_REG:
reg[inst.dst] = reg[inst.src];
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_ARSH_IMM:
reg[inst.dst] = (int32_t)reg[inst.dst] >> inst.imm;
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_ARSH_REG:
reg[inst.dst] = (int32_t)reg[inst.dst] >> u32(reg[inst.src]);
reg[inst.dst] &= UINT32_MAX;
break;
case EBPF_OP_LE:
if (inst.imm == 16) {
reg[inst.dst] = htole16(reg[inst.dst]);
} else if (inst.imm == 32) {
reg[inst.dst] = htole32(reg[inst.dst]);
} else if (inst.imm == 64) {
reg[inst.dst] = htole64(reg[inst.dst]);
}
break;
case EBPF_OP_BE:
if (inst.imm == 16) {
reg[inst.dst] = htobe16(reg[inst.dst]);
} else if (inst.imm == 32) {
reg[inst.dst] = htobe32(reg[inst.dst]);
} else if (inst.imm == 64) {
reg[inst.dst] = htobe64(reg[inst.dst]);
}
break;
case EBPF_OP_ADD64_IMM:
reg[inst.dst] += inst.imm;
break;
case EBPF_OP_ADD64_REG:
reg[inst.dst] += reg[inst.src];
break;
case EBPF_OP_SUB64_IMM:
reg[inst.dst] -= inst.imm;
break;
case EBPF_OP_SUB64_REG:
reg[inst.dst] -= reg[inst.src];
break;
case EBPF_OP_MUL64_IMM:
reg[inst.dst] *= inst.imm;
break;
case EBPF_OP_MUL64_REG:
reg[inst.dst] *= reg[inst.src];
break;
case EBPF_OP_DIV64_IMM:
reg[inst.dst] = inst.imm ? reg[inst.dst] / inst.imm : 0;
break;
case EBPF_OP_DIV64_REG:
reg[inst.dst] = reg[inst.src] ? reg[inst.dst] / reg[inst.src] : 0;
break;
case EBPF_OP_OR64_IMM:
reg[inst.dst] |= inst.imm;
break;
case EBPF_OP_OR64_REG:
reg[inst.dst] |= reg[inst.src];
break;
case EBPF_OP_AND64_IMM:
reg[inst.dst] &= inst.imm;
break;
case EBPF_OP_AND64_REG:
reg[inst.dst] &= reg[inst.src];
break;
case EBPF_OP_LSH64_IMM:
reg[inst.dst] <<= SHIFT_MASK_64_BIT(inst.imm);
break;
case EBPF_OP_LSH64_REG:
reg[inst.dst] <<= SHIFT_MASK_64_BIT(reg[inst.src]);
break;
case EBPF_OP_RSH64_IMM:
reg[inst.dst] >>= SHIFT_MASK_64_BIT(inst.imm);
break;
case EBPF_OP_RSH64_REG:
reg[inst.dst] >>= SHIFT_MASK_64_BIT(reg[inst.src]);
break;
case EBPF_OP_NEG64:
reg[inst.dst] = -reg[inst.dst];
break;
case EBPF_OP_MOD64_IMM:
reg[inst.dst] = inst.imm ? reg[inst.dst] % inst.imm : reg[inst.dst];
break;
case EBPF_OP_MOD64_REG:
reg[inst.dst] = reg[inst.src] ? reg[inst.dst] % reg[inst.src] : reg[inst.dst];
break;
case EBPF_OP_XOR64_IMM:
reg[inst.dst] ^= inst.imm;
break;
case EBPF_OP_XOR64_REG:
reg[inst.dst] ^= reg[inst.src];
break;
case EBPF_OP_MOV64_IMM:
reg[inst.dst] = inst.imm;
break;
case EBPF_OP_MOV64_REG:
reg[inst.dst] = reg[inst.src];
break;
case EBPF_OP_ARSH64_IMM:
reg[inst.dst] = (int64_t)reg[inst.dst] >> inst.imm;
break;
case EBPF_OP_ARSH64_REG:
reg[inst.dst] = (int64_t)reg[inst.dst] >> reg[inst.src];
break;
/*
* HACK runtime bounds check
*
* Needed since we don't have a verifier yet.
*/
#define BOUNDS_CHECK_LOAD(size) \
do { \
if (!bounds_check(vm, (char*)reg[inst.src] + inst.offset, size, "load", cur_pc, mem, mem_len, stack)) { \
return_value = -1; \
goto cleanup; \
} \
} while (0)
#define BOUNDS_CHECK_STORE(size) \
do { \
if (!bounds_check(vm, (char*)reg[inst.dst] + inst.offset, size, "store", cur_pc, mem, mem_len, stack)) { \
return_value = -1; \
goto cleanup; \
} \
} while (0)
case EBPF_OP_LDXW:
BOUNDS_CHECK_LOAD(4);
reg[inst.dst] = ubpf_mem_load(reg[inst.src] + inst.offset, 4);
break;
case EBPF_OP_LDXH:
BOUNDS_CHECK_LOAD(2);
reg[inst.dst] = ubpf_mem_load(reg[inst.src] + inst.offset, 2);
break;
case EBPF_OP_LDXB:
BOUNDS_CHECK_LOAD(1);
reg[inst.dst] = ubpf_mem_load(reg[inst.src] + inst.offset, 1);
break;
case EBPF_OP_LDXDW:
BOUNDS_CHECK_LOAD(8);
reg[inst.dst] = ubpf_mem_load(reg[inst.src] + inst.offset, 8);
break;
case EBPF_OP_STW:
BOUNDS_CHECK_STORE(4);
ubpf_mem_store(reg[inst.dst] + inst.offset, inst.imm, 4);
break;
case EBPF_OP_STH:
BOUNDS_CHECK_STORE(2);
ubpf_mem_store(reg[inst.dst] + inst.offset, inst.imm, 2);
break;
case EBPF_OP_STB:
BOUNDS_CHECK_STORE(1);
ubpf_mem_store(reg[inst.dst] + inst.offset, inst.imm, 1);
break;
case EBPF_OP_STDW:
BOUNDS_CHECK_STORE(8);
ubpf_mem_store(reg[inst.dst] + inst.offset, inst.imm, 8);
break;
case EBPF_OP_STXW:
BOUNDS_CHECK_STORE(4);
ubpf_mem_store(reg[inst.dst] + inst.offset, reg[inst.src], 4);
break;
case EBPF_OP_STXH:
BOUNDS_CHECK_STORE(2);
ubpf_mem_store(reg[inst.dst] + inst.offset, reg[inst.src], 2);
break;
case EBPF_OP_STXB:
BOUNDS_CHECK_STORE(1);
ubpf_mem_store(reg[inst.dst] + inst.offset, reg[inst.src], 1);
break;
case EBPF_OP_STXDW:
BOUNDS_CHECK_STORE(8);
ubpf_mem_store(reg[inst.dst] + inst.offset, reg[inst.src], 8);
break;
case EBPF_OP_LDDW:
reg[inst.dst] = u32(inst.imm) | ((uint64_t)ubpf_fetch_instruction(vm, pc++).imm << 32);
break;
case EBPF_OP_JA:
pc += inst.offset;
break;
case EBPF_OP_JEQ_IMM:
if (reg[inst.dst] == inst.imm) {
pc += inst.offset;
}
break;
case EBPF_OP_JEQ_REG:
if (reg[inst.dst] == reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JEQ32_IMM:
if (u32(reg[inst.dst]) == u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JEQ32_REG:
if (u32(reg[inst.dst]) == reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JGT_IMM:
if (reg[inst.dst] > u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JGT_REG:
if (reg[inst.dst] > reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JGT32_IMM:
if (u32(reg[inst.dst]) > u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JGT32_REG:
if (u32(reg[inst.dst]) > u32(reg[inst.src])) {
pc += inst.offset;
}
break;
case EBPF_OP_JGE_IMM:
if (reg[inst.dst] >= u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JGE_REG:
if (reg[inst.dst] >= reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JGE32_IMM:
if (u32(reg[inst.dst]) >= u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JGE32_REG:
if (u32(reg[inst.dst]) >= u32(reg[inst.src])) {
pc += inst.offset;
}
break;
case EBPF_OP_JLT_IMM:
if (reg[inst.dst] < u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JLT_REG:
if (reg[inst.dst] < reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JLT32_IMM:
if (u32(reg[inst.dst]) < u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JLT32_REG:
if (u32(reg[inst.dst]) < u32(reg[inst.src])) {
pc += inst.offset;
}
break;
case EBPF_OP_JLE_IMM:
if (reg[inst.dst] <= u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JLE_REG:
if (reg[inst.dst] <= reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JLE32_IMM:
if (u32(reg[inst.dst]) <= u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JLE32_REG:
if (u32(reg[inst.dst]) <= u32(reg[inst.src])) {
pc += inst.offset;
}
break;
case EBPF_OP_JSET_IMM:
if (reg[inst.dst] & inst.imm) {
pc += inst.offset;
}
break;
case EBPF_OP_JSET_REG:
if (reg[inst.dst] & reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JSET32_IMM:
if (u32(reg[inst.dst]) & u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JSET32_REG:
if (u32(reg[inst.dst]) & u32(reg[inst.src])) {
pc += inst.offset;
}
break;
case EBPF_OP_JNE_IMM:
if (reg[inst.dst] != inst.imm) {
pc += inst.offset;
}
break;
case EBPF_OP_JNE_REG:
if (reg[inst.dst] != reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JNE32_IMM:
if (u32(reg[inst.dst]) != u32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JNE32_REG:
if (u32(reg[inst.dst]) != u32(reg[inst.src])) {
pc += inst.offset;
}
break;
case EBPF_OP_JSGT_IMM:
if ((int64_t)reg[inst.dst] > inst.imm) {
pc += inst.offset;
}
break;
case EBPF_OP_JSGT_REG:
if ((int64_t)reg[inst.dst] > (int64_t)reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JSGT32_IMM:
if (i32(reg[inst.dst]) > i32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JSGT32_REG:
if (i32(reg[inst.dst]) > i32(reg[inst.src])) {
pc += inst.offset;
}
break;
case EBPF_OP_JSGE_IMM:
if ((int64_t)reg[inst.dst] >= inst.imm) {
pc += inst.offset;
}
break;
case EBPF_OP_JSGE_REG:
if ((int64_t)reg[inst.dst] >= (int64_t)reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JSGE32_IMM:
if (i32(reg[inst.dst]) >= i32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JSGE32_REG:
if (i32(reg[inst.dst]) >= i32(reg[inst.src])) {
pc += inst.offset;
}
break;
case EBPF_OP_JSLT_IMM:
if ((int64_t)reg[inst.dst] < inst.imm) {
pc += inst.offset;
}
break;
case EBPF_OP_JSLT_REG:
if ((int64_t)reg[inst.dst] < (int64_t)reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JSLT32_IMM:
if (i32(reg[inst.dst]) < i32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JSLT32_REG:
if (i32(reg[inst.dst]) < i32(reg[inst.src])) {
pc += inst.offset;
}
break;
case EBPF_OP_JSLE_IMM:
if ((int64_t)reg[inst.dst] <= inst.imm) {
pc += inst.offset;
}
break;
case EBPF_OP_JSLE_REG:
if ((int64_t)reg[inst.dst] <= (int64_t)reg[inst.src]) {
pc += inst.offset;
}
break;
case EBPF_OP_JSLE32_IMM:
if (i32(reg[inst.dst]) <= i32(inst.imm)) {
pc += inst.offset;
}
break;
case EBPF_OP_JSLE32_REG:
if (i32(reg[inst.dst]) <= i32(reg[inst.src])) {
pc += inst.offset;
}
break;
case EBPF_OP_EXIT:
if (ras_index > 0) {
ras_index--;
pc = stack_frames[ras_index].return_address;
reg[BPF_REG_6] = stack_frames[ras_index].saved_registers[0];
reg[BPF_REG_7] = stack_frames[ras_index].saved_registers[1];
reg[BPF_REG_8] = stack_frames[ras_index].saved_registers[2];
reg[BPF_REG_9] = stack_frames[ras_index].saved_registers[3];
break;
}
*bpf_return_value = reg[0];
return_value = 0;
goto cleanup;
case EBPF_OP_CALL:
// Differentiate between local and external calls -- assume that the
// program was assembled with the same endianess as the host machine.
if (inst.src == 0) {
// Handle call by address to external function.
// reg[0] = vm->ext_funcs[inst.imm](reg[1], reg[2], reg[3], reg[4], reg[5]);
reg[0] = ubpf_dispatch_to_external_helper(reg[1], reg[2], reg[3], reg[4], reg[5], vm, inst.imm);
// Unwind the stack if unwind extension returns success.
if (inst.imm == vm->unwind_stack_extension_index && reg[0] == 0) {
*bpf_return_value = reg[0];
return_value = 0;
goto cleanup;
}
} else if (inst.src == 1) {
if (ras_index >= UBPF_MAX_CALL_DEPTH) {
vm->error_printf(
stderr,
"uBPF error: number of nested functions calls (%lu) exceeds max (%lu) at PC %u\n",
ras_index + 1,
UBPF_MAX_CALL_DEPTH,
cur_pc);
return_value = -1;
goto cleanup;
}
stack_frames[ras_index].saved_registers[0] = reg[BPF_REG_6];
stack_frames[ras_index].saved_registers[1] = reg[BPF_REG_7];
stack_frames[ras_index].saved_registers[2] = reg[BPF_REG_8];
stack_frames[ras_index].saved_registers[3] = reg[BPF_REG_9];
stack_frames[ras_index].return_address = pc;
ras_index++;
pc += inst.imm;
break;
} else if (inst.src == 2) {
// Calling external function by BTF ID is not yet supported.
return_value = -1;
goto cleanup;
}
// Because we have already validated, we can assume that the type code is
// valid.
break;
}
}
cleanup:
#if defined(NTDDI_VERSION) && defined(WINNT)
free(stack_frames);
free(stack);
#endif
return return_value;
}
static bool
validate(const struct ubpf_vm* vm, const struct ebpf_inst* insts, uint32_t num_insts, char** errmsg)
{
if (num_insts >= UBPF_MAX_INSTS) {
*errmsg = ubpf_error("too many instructions (max %u)", UBPF_MAX_INSTS);
return false;
}
int i;
for (i = 0; i < num_insts; i++) {
struct ebpf_inst inst = insts[i];
bool store = false;
switch (inst.opcode) {
case EBPF_OP_ADD_IMM:
case EBPF_OP_ADD_REG:
case EBPF_OP_SUB_IMM:
case EBPF_OP_SUB_REG:
case EBPF_OP_MUL_IMM:
case EBPF_OP_MUL_REG:
case EBPF_OP_DIV_REG:
case EBPF_OP_OR_IMM:
case EBPF_OP_OR_REG:
case EBPF_OP_AND_IMM:
case EBPF_OP_AND_REG:
case EBPF_OP_LSH_IMM:
case EBPF_OP_LSH_REG:
case EBPF_OP_RSH_IMM:
case EBPF_OP_RSH_REG:
case EBPF_OP_NEG:
case EBPF_OP_MOD_REG:
case EBPF_OP_XOR_IMM:
case EBPF_OP_XOR_REG:
case EBPF_OP_MOV_IMM:
case EBPF_OP_MOV_REG:
case EBPF_OP_ARSH_IMM:
case EBPF_OP_ARSH_REG:
break;
case EBPF_OP_LE:
case EBPF_OP_BE:
if (inst.imm != 16 && inst.imm != 32 && inst.imm != 64) {
*errmsg = ubpf_error("invalid endian immediate at PC %d", i);
return false;
}
break;
case EBPF_OP_ADD64_IMM:
case EBPF_OP_ADD64_REG:
case EBPF_OP_SUB64_IMM:
case EBPF_OP_SUB64_REG:
case EBPF_OP_MUL64_IMM:
case EBPF_OP_MUL64_REG:
case EBPF_OP_DIV64_REG:
case EBPF_OP_OR64_IMM:
case EBPF_OP_OR64_REG:
case EBPF_OP_AND64_IMM:
case EBPF_OP_AND64_REG:
case EBPF_OP_LSH64_IMM:
case EBPF_OP_LSH64_REG: