295 lines
11 KiB
Rust
295 lines
11 KiB
Rust
#![allow(clippy::upper_case_acronyms)]
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use crate::BpfError;
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use solana_rbpf::ebpf;
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use thiserror::Error;
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/// Error definitions
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#[derive(Debug, Error, PartialEq)]
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pub enum VerifierError {
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/// ProgramLengthNotMultiple
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#[error("program length must be a multiple of {} octets", ebpf::INSN_SIZE)]
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ProgramLengthNotMultiple,
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/// ProgramTooLarge
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#[error("program too big, max {}, is {}", ebpf::PROG_MAX_INSNS, .0)]
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ProgramTooLarge(usize),
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/// NoProgram
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#[error("no program set, call prog_set() to load one")]
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NoProgram,
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#[error("division by 0 (insn #{0})")]
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DivisionByZero(usize),
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/// UnsupportedLEBEArgument
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#[error("unsupported argument for LE/BE (insn #{0})")]
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UnsupportedLEBEArgument(usize),
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/// LDDWCannotBeLast
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#[error("LD_DW instruction cannot be last in program")]
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LDDWCannotBeLast,
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/// IncompleteLDDW
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#[error("incomplete LD_DW instruction (insn #{0})")]
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IncompleteLDDW(usize),
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/// InfiniteLoop
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#[error("infinite loop (insn #{0})")]
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InfiniteLoop(usize),
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/// JumpOutOfCode
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#[error("jump out of code to #{0} (insn #{1})")]
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JumpOutOfCode(usize, usize),
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/// JumpToMiddleOfLDDW
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#[error("jump to middle of LD_DW at #{0} (insn #{1})")]
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JumpToMiddleOfLDDW(usize, usize),
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/// InvalidSourceRegister
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#[error("invalid source register (insn #{0})")]
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InvalidSourceRegister(usize),
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/// CannotWriteR10
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#[error("cannot write into register r10 (insn #{0})")]
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CannotWriteR10(usize),
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/// InvalidDestinationRegister
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#[error("invalid destination register (insn #{0})")]
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InvalidDestinationRegister(usize),
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/// UnknownOpCode
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#[error("unknown eBPF opcode {0:#2x} (insn #{1:?})")]
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UnknownOpCode(u8, usize),
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/// Shift with overflow
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#[error("Shift with overflow at instruction {0}")]
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ShiftWithOverflow(usize),
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/// Invalid register specified
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#[error("Invalid register specified at instruction {0}")]
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InvalidRegister(usize),
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}
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fn adj_insn_ptr(insn_ptr: usize) -> usize {
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insn_ptr + ebpf::ELF_INSN_DUMP_OFFSET
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}
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fn check_prog_len(prog: &[u8]) -> Result<(), BpfError> {
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if prog.len() % ebpf::INSN_SIZE != 0 {
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return Err(VerifierError::ProgramLengthNotMultiple.into());
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}
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if prog.is_empty() {
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return Err(VerifierError::NoProgram.into());
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}
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Ok(())
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}
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fn check_imm_nonzero(insn: &ebpf::Insn, insn_ptr: usize) -> Result<(), BpfError> {
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if insn.imm == 0 {
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return Err(VerifierError::DivisionByZero(adj_insn_ptr(insn_ptr)).into());
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}
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Ok(())
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}
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fn check_imm_endian(insn: &ebpf::Insn, insn_ptr: usize) -> Result<(), BpfError> {
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match insn.imm {
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16 | 32 | 64 => Ok(()),
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_ => Err(VerifierError::UnsupportedLEBEArgument(adj_insn_ptr(insn_ptr)).into()),
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}
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}
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fn check_load_dw(prog: &[u8], insn_ptr: usize) -> Result<(), BpfError> {
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if insn_ptr + 1 >= (prog.len() / ebpf::INSN_SIZE) {
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// Last instruction cannot be LD_DW because there would be no 2nd DW
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return Err(VerifierError::LDDWCannotBeLast.into());
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}
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let next_insn = ebpf::get_insn(prog, insn_ptr + 1);
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if next_insn.opc != 0 {
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return Err(VerifierError::IncompleteLDDW(adj_insn_ptr(insn_ptr)).into());
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}
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Ok(())
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}
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fn check_jmp_offset(prog: &[u8], insn_ptr: usize) -> Result<(), BpfError> {
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let insn = ebpf::get_insn(prog, insn_ptr);
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// if insn.off == -1 {
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// return Err(VerifierError::InfiniteLoop(adj_insn_ptr(insn_ptr)).into());
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// }
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let dst_insn_ptr = insn_ptr as isize + 1 + insn.off as isize;
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if dst_insn_ptr < 0 || dst_insn_ptr as usize >= (prog.len() / ebpf::INSN_SIZE) {
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return Err(
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VerifierError::JumpOutOfCode(dst_insn_ptr as usize, adj_insn_ptr(insn_ptr)).into(),
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);
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}
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let dst_insn = ebpf::get_insn(prog, dst_insn_ptr as usize);
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if dst_insn.opc == 0 {
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return Err(VerifierError::JumpToMiddleOfLDDW(
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dst_insn_ptr as usize,
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adj_insn_ptr(insn_ptr),
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)
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.into());
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}
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Ok(())
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}
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fn check_registers(insn: &ebpf::Insn, store: bool, insn_ptr: usize) -> Result<(), BpfError> {
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if insn.src > 10 {
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return Err(VerifierError::InvalidSourceRegister(adj_insn_ptr(insn_ptr)).into());
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}
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match (insn.dst, store) {
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(0..=9, _) | (10, true) => Ok(()),
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(10, false) => Err(VerifierError::CannotWriteR10(adj_insn_ptr(insn_ptr)).into()),
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(_, _) => Err(VerifierError::InvalidDestinationRegister(adj_insn_ptr(insn_ptr)).into()),
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}
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}
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/// Check that the imm is a valid shift operand
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fn check_imm_shift(insn: &ebpf::Insn, insn_ptr: usize) -> Result<(), VerifierError> {
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if insn.imm < 0 || insn.imm as u64 >= 64 {
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return Err(VerifierError::ShiftWithOverflow(adj_insn_ptr(insn_ptr)));
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}
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Ok(())
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}
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/// Check that the imm is a valid register number
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fn check_imm_register(insn: &ebpf::Insn, insn_ptr: usize) -> Result<(), VerifierError> {
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if insn.imm < 0 || insn.imm > 10 {
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return Err(VerifierError::InvalidRegister(adj_insn_ptr(insn_ptr)));
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}
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Ok(())
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}
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#[rustfmt::skip]
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pub fn check(prog: &[u8]) -> Result<(), BpfError> {
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check_prog_len(prog)?;
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let mut insn_ptr: usize = 0;
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while insn_ptr * ebpf::INSN_SIZE < prog.len() {
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let insn = ebpf::get_insn(prog, insn_ptr);
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let mut store = false;
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match insn.opc {
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// BPF_LD class
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ebpf::LD_ABS_B => {},
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ebpf::LD_ABS_H => {},
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ebpf::LD_ABS_W => {},
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ebpf::LD_ABS_DW => {},
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ebpf::LD_IND_B => {},
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ebpf::LD_IND_H => {},
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ebpf::LD_IND_W => {},
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ebpf::LD_IND_DW => {},
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ebpf::LD_DW_IMM => {
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store = true;
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check_load_dw(prog, insn_ptr)?;
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insn_ptr += 1;
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},
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// BPF_LDX class
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ebpf::LD_B_REG => {},
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ebpf::LD_H_REG => {},
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ebpf::LD_W_REG => {},
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ebpf::LD_DW_REG => {},
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// BPF_ST class
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ebpf::ST_B_IMM => store = true,
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ebpf::ST_H_IMM => store = true,
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ebpf::ST_W_IMM => store = true,
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ebpf::ST_DW_IMM => store = true,
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// BPF_STX class
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ebpf::ST_B_REG => store = true,
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ebpf::ST_H_REG => store = true,
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ebpf::ST_W_REG => store = true,
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ebpf::ST_DW_REG => store = true,
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// BPF_ALU class
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ebpf::ADD32_IMM => {},
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ebpf::ADD32_REG => {},
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ebpf::SUB32_IMM => {},
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ebpf::SUB32_REG => {},
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ebpf::MUL32_IMM => {},
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ebpf::MUL32_REG => {},
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ebpf::DIV32_IMM => { check_imm_nonzero(&insn, insn_ptr)?; },
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ebpf::DIV32_REG => {},
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ebpf::OR32_IMM => {},
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ebpf::OR32_REG => {},
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ebpf::AND32_IMM => {},
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ebpf::AND32_REG => {},
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ebpf::LSH32_IMM => { check_imm_shift(&insn, insn_ptr)?; },
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ebpf::LSH32_REG => {},
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ebpf::RSH32_IMM => { check_imm_shift(&insn, insn_ptr)?; },
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ebpf::RSH32_REG => {},
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ebpf::NEG32 => {},
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ebpf::MOD32_IMM => { check_imm_nonzero(&insn, insn_ptr)?; },
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ebpf::MOD32_REG => {},
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ebpf::XOR32_IMM => {},
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ebpf::XOR32_REG => {},
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ebpf::MOV32_IMM => {},
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ebpf::MOV32_REG => {},
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ebpf::ARSH32_IMM => { check_imm_shift(&insn, insn_ptr)?; },
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ebpf::ARSH32_REG => {},
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ebpf::LE => { check_imm_endian(&insn, insn_ptr)?; },
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ebpf::BE => { check_imm_endian(&insn, insn_ptr)?; },
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// BPF_ALU64 class
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ebpf::ADD64_IMM => {},
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ebpf::ADD64_REG => {},
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ebpf::SUB64_IMM => {},
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ebpf::SUB64_REG => {},
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ebpf::MUL64_IMM => { check_imm_nonzero(&insn, insn_ptr)?; },
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ebpf::MUL64_REG => {},
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ebpf::DIV64_IMM => { check_imm_nonzero(&insn, insn_ptr)?; },
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ebpf::DIV64_REG => {},
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ebpf::OR64_IMM => {},
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ebpf::OR64_REG => {},
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ebpf::AND64_IMM => {},
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ebpf::AND64_REG => {},
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ebpf::LSH64_IMM => { check_imm_shift(&insn, insn_ptr)?; },
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ebpf::LSH64_REG => {},
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ebpf::RSH64_IMM => { check_imm_shift(&insn, insn_ptr)?; },
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ebpf::RSH64_REG => {},
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ebpf::NEG64 => {},
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ebpf::MOD64_IMM => { check_imm_nonzero(&insn, insn_ptr)?; },
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ebpf::MOD64_REG => {},
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ebpf::XOR64_IMM => {},
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ebpf::XOR64_REG => {},
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ebpf::MOV64_IMM => {},
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ebpf::MOV64_REG => {},
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ebpf::ARSH64_IMM => { check_imm_shift(&insn, insn_ptr)?; },
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ebpf::ARSH64_REG => {},
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// BPF_JMP class
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ebpf::JA => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JEQ_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JEQ_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JGT_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JGT_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JGE_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JGE_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JLT_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JLT_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JLE_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JLE_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JSET_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JSET_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JNE_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JNE_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JSGT_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JSGT_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JSGE_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JSGE_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JSLT_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JSLT_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JSLE_IMM => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::JSLE_REG => { check_jmp_offset(prog, insn_ptr)?; },
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ebpf::CALL_IMM => {},
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ebpf::CALL_REG => { check_imm_register(&insn, insn_ptr)?; },
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ebpf::EXIT => {},
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_ => {
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return Err(VerifierError::UnknownOpCode(insn.opc, adj_insn_ptr(insn_ptr)).into());
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}
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}
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check_registers(&insn, store, insn_ptr)?;
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insn_ptr += 1;
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}
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// insn_ptr should now be equal to number of instructions.
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if insn_ptr != prog.len() / ebpf::INSN_SIZE {
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return Err(VerifierError::JumpOutOfCode(adj_insn_ptr(insn_ptr), adj_insn_ptr(insn_ptr)).into());
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}
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Ok(())
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}
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