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disassembler.rs
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disassembler.rs
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#![allow(clippy::arithmetic_side_effects)]
// Copyright 2017 6WIND S.A. <quentin.monnet@6wind.com>
//
// Licensed under the Apache License, Version 2.0 <http://www.apache.org/licenses/LICENSE-2.0> or
// the MIT license <http://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.
//! Functions in this module are used to handle eBPF programs with a higher level representation,
//! for example to disassemble the code into a human-readable format.
use crate::{
ebpf,
program::{BuiltinProgram, FunctionRegistry, SBPFVersion},
static_analysis::CfgNode,
vm::ContextObject,
};
use std::collections::BTreeMap;
fn resolve_label(cfg_nodes: &BTreeMap<usize, CfgNode>, pc: usize) -> &str {
cfg_nodes
.get(&pc)
.map(|cfg_node| cfg_node.label.as_str())
.unwrap_or("[invalid]")
}
#[inline]
fn alu_imm_str(name: &str, insn: &ebpf::Insn) -> String {
format!("{} r{}, {}", name, insn.dst, insn.imm)
}
#[inline]
fn alu_reg_str(name: &str, insn: &ebpf::Insn) -> String {
format!("{} r{}, r{}", name, insn.dst, insn.src)
}
#[inline]
fn byteswap_str(name: &str, insn: &ebpf::Insn) -> String {
match insn.imm {
16 | 32 | 64 => {}
_ => println!("[Disassembler] Warning: Invalid offset value for {name} insn"),
}
format!("{}{} r{}", name, insn.imm, insn.dst)
}
#[inline]
fn signed_off_str(value: i16) -> String {
if value < 0 {
format!("-{:#x}", -value)
} else {
format!("+{value:#x}")
}
}
#[inline]
fn ld_st_imm_str(name: &str, insn: &ebpf::Insn) -> String {
format!(
"{} [r{}{}], {}",
name,
insn.dst,
signed_off_str(insn.off),
insn.imm
)
}
#[inline]
fn ld_reg_str(name: &str, insn: &ebpf::Insn) -> String {
format!(
"{} r{}, [r{}{}]",
name,
insn.dst,
insn.src,
signed_off_str(insn.off)
)
}
#[inline]
fn st_reg_str(name: &str, insn: &ebpf::Insn) -> String {
format!(
"{} [r{}{}], r{}",
name,
insn.dst,
signed_off_str(insn.off),
insn.src
)
}
#[inline]
fn jmp_imm_str(name: &str, insn: &ebpf::Insn, cfg_nodes: &BTreeMap<usize, CfgNode>) -> String {
let target_pc = (insn.ptr as isize + insn.off as isize + 1) as usize;
format!(
"{} r{}, {}, {}",
name,
insn.dst,
insn.imm,
resolve_label(cfg_nodes, target_pc)
)
}
#[inline]
fn jmp_reg_str(name: &str, insn: &ebpf::Insn, cfg_nodes: &BTreeMap<usize, CfgNode>) -> String {
let target_pc = (insn.ptr as isize + insn.off as isize + 1) as usize;
format!(
"{} r{}, r{}, {}",
name,
insn.dst,
insn.src,
resolve_label(cfg_nodes, target_pc)
)
}
/// Disassemble an eBPF instruction
#[rustfmt::skip]
pub fn disassemble_instruction<C: ContextObject>(
insn: &ebpf::Insn,
cfg_nodes: &BTreeMap<usize, CfgNode>,
function_registry: &FunctionRegistry<usize>,
loader: &BuiltinProgram<C>,
sbpf_version: &SBPFVersion,
) -> String {
let name;
let desc;
match insn.opc {
// BPF_LD class
ebpf::LD_DW_IMM => { name = "lddw"; desc = format!("{} r{:}, {:#x}", name, insn.dst, insn.imm); },
// BPF_LDX class
ebpf::LD_B_REG => { name = "ldxb"; desc = ld_reg_str(name, insn); },
ebpf::LD_H_REG => { name = "ldxh"; desc = ld_reg_str(name, insn); },
ebpf::LD_W_REG => { name = "ldxw"; desc = ld_reg_str(name, insn); },
ebpf::LD_DW_REG => { name = "ldxdw"; desc = ld_reg_str(name, insn); },
// BPF_ST class
ebpf::ST_B_IMM => { name = "stb"; desc = ld_st_imm_str(name, insn); },
ebpf::ST_H_IMM => { name = "sth"; desc = ld_st_imm_str(name, insn); },
ebpf::ST_W_IMM => { name = "stw"; desc = ld_st_imm_str(name, insn); },
ebpf::ST_DW_IMM => { name = "stdw"; desc = ld_st_imm_str(name, insn); },
// BPF_STX class
ebpf::ST_B_REG => { name = "stxb"; desc = st_reg_str(name, insn); },
ebpf::ST_H_REG => { name = "stxh"; desc = st_reg_str(name, insn); },
ebpf::ST_W_REG => { name = "stxw"; desc = st_reg_str(name, insn); },
ebpf::ST_DW_REG => { name = "stxdw"; desc = st_reg_str(name, insn); },
// BPF_ALU class
ebpf::ADD32_IMM => { name = "add32"; desc = alu_imm_str(name, insn); },
ebpf::ADD32_REG => { name = "add32"; desc = alu_reg_str(name, insn); },
ebpf::SUB32_IMM => { name = "sub32"; desc = alu_imm_str(name, insn); },
ebpf::SUB32_REG => { name = "sub32"; desc = alu_reg_str(name, insn); },
ebpf::MUL32_IMM => { name = "mul32"; desc = alu_imm_str(name, insn); },
ebpf::MUL32_REG => { name = "mul32"; desc = alu_reg_str(name, insn); },
ebpf::DIV32_IMM => { name = "div32"; desc = alu_imm_str(name, insn); },
ebpf::DIV32_REG => { name = "div32"; desc = alu_reg_str(name, insn); },
ebpf::OR32_IMM => { name = "or32"; desc = alu_imm_str(name, insn); },
ebpf::OR32_REG => { name = "or32"; desc = alu_reg_str(name, insn); },
ebpf::AND32_IMM => { name = "and32"; desc = alu_imm_str(name, insn); },
ebpf::AND32_REG => { name = "and32"; desc = alu_reg_str(name, insn); },
ebpf::LSH32_IMM => { name = "lsh32"; desc = alu_imm_str(name, insn); },
ebpf::LSH32_REG => { name = "lsh32"; desc = alu_reg_str(name, insn); },
ebpf::RSH32_IMM => { name = "rsh32"; desc = alu_imm_str(name, insn); },
ebpf::RSH32_REG => { name = "rsh32"; desc = alu_reg_str(name, insn); },
ebpf::NEG32 => { name = "neg32"; desc = format!("{} r{}", name, insn.dst); },
ebpf::MOD32_IMM => { name = "mod32"; desc = alu_imm_str(name, insn); },
ebpf::MOD32_REG => { name = "mod32"; desc = alu_reg_str(name, insn); },
ebpf::XOR32_IMM => { name = "xor32"; desc = alu_imm_str(name, insn); },
ebpf::XOR32_REG => { name = "xor32"; desc = alu_reg_str(name, insn); },
ebpf::MOV32_IMM => { name = "mov32"; desc = alu_imm_str(name, insn); },
ebpf::MOV32_REG => { name = "mov32"; desc = alu_reg_str(name, insn); },
ebpf::ARSH32_IMM => { name = "arsh32"; desc = alu_imm_str(name, insn); },
ebpf::ARSH32_REG => { name = "arsh32"; desc = alu_reg_str(name, insn); },
ebpf::LE => { name = "le"; desc = byteswap_str(name, insn); },
ebpf::BE => { name = "be"; desc = byteswap_str(name, insn); },
// BPF_ALU64 class
ebpf::ADD64_IMM => { name = "add64"; desc = alu_imm_str(name, insn); },
ebpf::ADD64_REG => { name = "add64"; desc = alu_reg_str(name, insn); },
ebpf::SUB64_IMM => { name = "sub64"; desc = alu_imm_str(name, insn); },
ebpf::SUB64_REG => { name = "sub64"; desc = alu_reg_str(name, insn); },
ebpf::MUL64_IMM => { name = "mul64"; desc = alu_imm_str(name, insn); },
ebpf::MUL64_REG => { name = "mul64"; desc = alu_reg_str(name, insn); },
ebpf::DIV64_IMM => { name = "div64"; desc = alu_imm_str(name, insn); },
ebpf::DIV64_REG => { name = "div64"; desc = alu_reg_str(name, insn); },
ebpf::OR64_IMM => { name = "or64"; desc = alu_imm_str(name, insn); },
ebpf::OR64_REG => { name = "or64"; desc = alu_reg_str(name, insn); },
ebpf::AND64_IMM => { name = "and64"; desc = alu_imm_str(name, insn); },
ebpf::AND64_REG => { name = "and64"; desc = alu_reg_str(name, insn); },
ebpf::LSH64_IMM => { name = "lsh64"; desc = alu_imm_str(name, insn); },
ebpf::LSH64_REG => { name = "lsh64"; desc = alu_reg_str(name, insn); },
ebpf::RSH64_IMM => { name = "rsh64"; desc = alu_imm_str(name, insn); },
ebpf::RSH64_REG => { name = "rsh64"; desc = alu_reg_str(name, insn); },
ebpf::NEG64 => { name = "neg64"; desc = format!("{} r{}", name, insn.dst); },
ebpf::MOD64_IMM => { name = "mod64"; desc = alu_imm_str(name, insn); },
ebpf::MOD64_REG => { name = "mod64"; desc = alu_reg_str(name, insn); },
ebpf::XOR64_IMM => { name = "xor64"; desc = alu_imm_str(name, insn); },
ebpf::XOR64_REG => { name = "xor64"; desc = alu_reg_str(name, insn); },
ebpf::MOV64_IMM => { name = "mov64"; desc = alu_imm_str(name, insn); },
ebpf::MOV64_REG => { name = "mov64"; desc = alu_reg_str(name, insn); },
ebpf::ARSH64_IMM => { name = "arsh64"; desc = alu_imm_str(name, insn); },
ebpf::ARSH64_REG => { name = "arsh64"; desc = alu_reg_str(name, insn); },
ebpf::HOR64_IMM => { name = "hor64"; desc = alu_imm_str(name, insn); },
// BPF_PQR class
ebpf::LMUL32_IMM => { name = "lmul32"; desc = alu_imm_str(name, insn); },
ebpf::LMUL32_REG => { name = "lmul32"; desc = alu_reg_str(name, insn); },
ebpf::LMUL64_IMM => { name = "lmul64"; desc = alu_imm_str(name, insn); },
ebpf::LMUL64_REG => { name = "lmul64"; desc = alu_reg_str(name, insn); },
ebpf::UHMUL64_IMM => { name = "uhmul64"; desc = alu_imm_str(name, insn); },
ebpf::UHMUL64_REG => { name = "uhmul64"; desc = alu_reg_str(name, insn); },
ebpf::SHMUL64_IMM => { name = "shmul64"; desc = alu_imm_str(name, insn); },
ebpf::SHMUL64_REG => { name = "shmul64"; desc = alu_reg_str(name, insn); },
ebpf::UDIV32_IMM => { name = "udiv32"; desc = alu_imm_str(name, insn); },
ebpf::UDIV32_REG => { name = "udiv32"; desc = alu_reg_str(name, insn); },
ebpf::UDIV64_IMM => { name = "udiv64"; desc = alu_imm_str(name, insn); },
ebpf::UDIV64_REG => { name = "udiv64"; desc = alu_reg_str(name, insn); },
ebpf::UREM32_IMM => { name = "urem32"; desc = alu_imm_str(name, insn); },
ebpf::UREM32_REG => { name = "urem32"; desc = alu_reg_str(name, insn); },
ebpf::UREM64_IMM => { name = "urem64"; desc = alu_imm_str(name, insn); },
ebpf::UREM64_REG => { name = "urem64"; desc = alu_reg_str(name, insn); },
ebpf::SDIV32_IMM => { name = "sdiv32"; desc = alu_imm_str(name, insn); },
ebpf::SDIV32_REG => { name = "sdiv32"; desc = alu_reg_str(name, insn); },
ebpf::SDIV64_IMM => { name = "sdiv64"; desc = alu_imm_str(name, insn); },
ebpf::SDIV64_REG => { name = "sdiv64"; desc = alu_reg_str(name, insn); },
ebpf::SREM32_IMM => { name = "srem32"; desc = alu_imm_str(name, insn); },
ebpf::SREM32_REG => { name = "srem32"; desc = alu_reg_str(name, insn); },
ebpf::SREM64_IMM => { name = "srem64"; desc = alu_imm_str(name, insn); },
ebpf::SREM64_REG => { name = "srem64"; desc = alu_reg_str(name, insn); },
// BPF_JMP class
ebpf::JA => {
name = "ja";
let target_pc = (insn.ptr as isize + insn.off as isize + 1) as usize;
desc = format!("{} {}", name, resolve_label(cfg_nodes, target_pc));
},
ebpf::JEQ_IMM => { name = "jeq"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JEQ_REG => { name = "jeq"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::JGT_IMM => { name = "jgt"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JGT_REG => { name = "jgt"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::JGE_IMM => { name = "jge"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JGE_REG => { name = "jge"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::JLT_IMM => { name = "jlt"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JLT_REG => { name = "jlt"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::JLE_IMM => { name = "jle"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JLE_REG => { name = "jle"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::JSET_IMM => { name = "jset"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JSET_REG => { name = "jset"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::JNE_IMM => { name = "jne"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JNE_REG => { name = "jne"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::JSGT_IMM => { name = "jsgt"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JSGT_REG => { name = "jsgt"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::JSGE_IMM => { name = "jsge"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JSGE_REG => { name = "jsge"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::JSLT_IMM => { name = "jslt"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JSLT_REG => { name = "jslt"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::JSLE_IMM => { name = "jsle"; desc = jmp_imm_str(name, insn, cfg_nodes); },
ebpf::JSLE_REG => { name = "jsle"; desc = jmp_reg_str(name, insn, cfg_nodes); },
ebpf::CALL_IMM => {
let mut function_name = None;
if sbpf_version.static_syscalls() {
if insn.src != 0 {
function_name = Some(resolve_label(cfg_nodes, insn.imm as usize).to_string());
}
} else {
function_name = function_registry.lookup_by_key(insn.imm as u32).map(|(function_name, _)| String::from_utf8_lossy(function_name).to_string());
}
let function_name = if let Some(function_name) = function_name {
name = "call";
function_name
} else {
name = "syscall";
loader.get_function_registry().lookup_by_key(insn.imm as u32).map(|(function_name, _)| String::from_utf8_lossy(function_name).to_string()).unwrap_or_else(|| "[invalid]".to_string())
};
desc = format!("{name} {function_name}");
},
ebpf::CALL_REG => { name = "callx"; desc = format!("{} r{}", name, if sbpf_version.callx_uses_src_reg() { insn.src } else { insn.imm as u8 }); },
ebpf::EXIT => { name = "exit"; desc = name.to_string(); },
_ => { name = "unknown"; desc = format!("{} opcode={:#x}", name, insn.opc); },
};
desc
}