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/*! Length Disassembler =================== Supports `x86` and `x86_64` up to `SSE4.2`. Valid opcodes will be length disassembled correctly. Invalid opcodes may be rejected on a best-effort basis. ## Examples Gets the length of the first opcode in a byte slice: ``` let result = lde::X64.ld(b"\x40\x55\x48\x83\xEC\xFC\x00\x80"); assert_eq!(result, 2); ``` Iterates over the opcodes contained in a byte slice, returning the opcode and its virtual address: ``` let code = b"\x40\x55\x48\x83\xEC*\x00\x80"; # let mut result_opcodes = vec![&code[0..2], &code[2..6]].into_iter(); # let mut result_vas = vec![0x1000, 0x1002].into_iter(); for (opcode, va) in lde::X64.iter(code, 0x1000) { println!("{:x}: {}", va, opcode); # assert_eq!(result_opcodes.next(), Some(opcode.into())); # assert_eq!(result_vas.next(), Some(va)); } // 1000: 4055 // 1002: 4883EC2A ``` Find the opcode boundary after a minimum of 5 bytes: ``` // 1000: 56 push esi // 1001: 33f6 xor esi,esi // 1003: 57 push edi // 1004: bfa0104000 mov edi,0x4010a0 // 1009: 85d2 test edx,edx // 100b: 7410 je loc_0000001d // 100d: 8bf2 mov esi,edx // 100f: 8bfa mov edi,edx const INPUT_CODE: &[u8] = b"\x56\x33\xF6\x57\xBF\xA0\x10\x40\x00\x85\xD2\x74\x10\x8B\xF2\x8B\xFA"; // We'd like to overwrite the first 5 bytes with a jmp hook // Find how many opcodes need to be copied for our hook to work let mut count = 0; for (opcode, _) in lde::X86.iter(INPUT_CODE, 0x1000) { count += opcode.len(); if count >= 5 { break; } } // The answer is the first 4 opcodes, or 9 bytes assert_eq!(count, 9); ``` Custom `Display` and `Debug` formatting including pretty printing support with the alternate flag: ``` let iter = lde::X64.iter(b"\x40\x55\x48\x83\xEC*\x00\x80", 0); assert_eq!(format!("{:?}", iter), "[4055] [4883EC2A] 0080"); assert_eq!(format!("{:#?}", iter), "[40 55] [48 83 EC 2A] 00 80"); assert_eq!(format!("{:}", iter), "4055\n4883EC2A\n"); assert_eq!(format!("{:#}", iter), "40 55\n48 83 EC 2A\n"); ``` */ #![no_std] use core::{cmp, ops}; #[cfg(test)] #[macro_use] extern crate std; mod lde; mod opcode; pub use self::opcode::OpCode; mod builder; pub use self::builder::OcBuilder; mod iter; pub use self::iter::Iter; mod iter_mut; pub use self::iter_mut::IterMut; //---------------------------------------------------------------- /// Defines a type which can be safely constructed from a byte array of the same size. /// /// Used to allow reading/writing immediates and displacements. pub unsafe trait Int: Copy + 'static {} unsafe impl Int for u8 {} unsafe impl Int for u16 {} unsafe impl Int for u32 {} unsafe impl Int for u64 {} unsafe impl Int for i8 {} unsafe impl Int for i16 {} unsafe impl Int for i32 {} unsafe impl Int for i64 {} /// Virtual address type. pub trait Va: Copy + Ord + ops::Add<Output = Self> + ops::AddAssign {} impl Va for u32 {} impl Va for u64 {} /// Instruction set architecture. /// /// Defines the entry points for the length disassembler. pub trait Isa: Sized { /// Virtual address type. type Va: Va; /// Returns the length of the first opcode in the given byte slice. /// /// When length disassembling fails, eg. the byte slice does not contain a complete and valid instruction, the return value is `0`. fn ld(bytes: &[u8]) -> u32; /// Returns the first opcode in the byte slice if successful. fn peek(bytes: &[u8]) -> Option<&OpCode> { // The ld function guarantees that the returned length does not exceed the input byte length // Convince the optimizer that this indeed the case with a cmp::min let len = cmp::min(Self::ld(bytes) as usize, bytes.len()); if len > 0 { Some((&bytes[..len]).into()) } else { None } } /// Returns the first opcode mutably in the byte slice if successful. fn peek_mut(bytes: &mut [u8]) -> Option<&mut OpCode> { // The ld function guarantees that the returned length does not exceed the input byte length // Convince the optimizer that this indeed the case with a cmp::min let len = cmp::min(Self::ld(bytes) as usize, bytes.len()); if len > 0 { Some((&mut bytes[..len]).into()) } else { None } } /// Returns an iterator over the opcodes contained in the byte slice. /// /// Given a virtual address to keep track of the instruction pointer. fn iter<'a>(bytes: &'a [u8], va: Self::Va) -> Iter<'a, Self> { Iter { bytes, va } } /// Returns an iterator over the opcodes contained in the byte slice. /// /// Given a virtual address to keep track of the instruction pointer. fn iter_mut<'a>(bytes: &'a mut [u8], va: Self::Va) -> IterMut<'a, Self> { IterMut { bytes, va } } #[doc(hidden)] fn as_va(len: usize) -> Self::Va; } //---------------------------------------------------------------- /// Length disassembler for the `x86` instruction set architecture. pub struct X86; impl Isa for X86 { type Va = u32; fn ld(bytes: &[u8]) -> u32 { lde::x86::lde_int(bytes) } #[doc(hidden)] fn as_va(len: usize) -> u32 { len as u32 } } impl X86 { /// Returns the length of the first opcode in the given byte slice. /// /// When length disassembling fails, eg. the byte slice does not contain a complete and valid instruction, the return value is `0`. pub fn ld(self, bytes: &[u8]) -> u32 { <X86 as Isa>::ld(bytes) } /// Returns the first opcode in the byte slice if successful. pub fn peek(self, bytes: &[u8]) -> Option<&OpCode> { <X86 as Isa>::peek(bytes) } /// Returns the first opcode mutably in the byte slice if successful. pub fn peek_mut(self, bytes: &mut [u8]) -> Option<&mut OpCode> { <X86 as Isa>::peek_mut(bytes) } /// Returns an iterator over the opcodes contained in the byte slice. /// /// Given a virtual address to keep track of the instruction pointer. pub fn iter<'a>(self, bytes: &'a [u8], va: u32) -> Iter<'a, X86> { <X86 as Isa>::iter(bytes, va) } /// Returns an iterator over the opcodes contained in the byte slice. /// /// Given a virtual address to keep track of the instruction pointer. pub fn iter_mut<'a>(self, bytes: &'a mut [u8], va: u32) -> IterMut<'a, X86> { <X86 as Isa>::iter_mut(bytes, va) } } /// Length disassembler for the `x86_64` instruction set architecture. pub struct X64; impl Isa for X64 { type Va = u64; fn ld(bytes: &[u8]) -> u32 { lde::x64::lde_int(bytes) } #[doc(hidden)] fn as_va(len: usize) -> u64 { len as u64 } } impl X64 { /// Returns the length of the first opcode in the given byte slice. /// /// When length disassembling fails, eg. the byte slice does not contain a complete and valid instruction, the return value is `0`. /// /// # Examples /// /// ``` /// let code = b"\x40\x55\x48\x83\xEC*\x00\x80"; /// assert_eq!(lde::X64.ld(code), 2); /// ``` /// /// ``` /// let invalid = b""; /// assert_eq!(lde::X64.ld(invalid), 0); /// ``` pub fn ld(self, bytes: &[u8]) -> u32 { <X64 as Isa>::ld(bytes) } /// Returns the first opcode in the byte slice if successful. /// /// # Examples /// /// ``` /// let code = b"\x40\x55\x48\x83\xEC*\x00\x80"; /// assert_eq!(lde::X64.peek(code), Some(b"\x40\x55".into())); /// ``` pub fn peek(self, bytes: &[u8]) -> Option<&OpCode> { <X64 as Isa>::peek(bytes) } /// Returns the first opcode mutably in the byte slice if successful. pub fn peek_mut(self, bytes: &mut [u8]) -> Option<&mut OpCode> { <X64 as Isa>::peek_mut(bytes) } /// Returns an iterator over the opcodes contained in the byte slice. /// /// Given a virtual address to keep track of the instruction pointer. /// /// # Examples /// /// ``` /// let code = b"\x40\x55\x48\x83\xEC*\x00\x80"; /// # let mut result_opcodes = vec![&code[0..2], &code[2..6]].into_iter(); /// # let mut result_vas = vec![0x1000, 0x1002].into_iter(); /// /// for (opcode, va) in lde::X64.iter(code, 0x1000) { /// println!("{:x}: {}", va, opcode); /// # assert_eq!(result_opcodes.next(), Some(opcode.into())); /// # assert_eq!(result_vas.next(), Some(va)); /// } /// ``` /// /// Prints the following result /// /// ```text /// 1000: 4055 /// 1002: 4883EC2A /// ``` pub fn iter<'a>(self, bytes: &'a [u8], va: u64) -> Iter<'a, X64> { <X64 as Isa>::iter(bytes, va) } /// Returns an iterator over the opcodes contained in the byte slice. /// /// Given a virtual address to keep track of the instruction pointer. /// /// # Examples /// /// ``` /// let mut code = *b"\x40\x55\x48\x83\xEC*\x00\x80"; /// /// for (opcode, va) in lde::X64.iter_mut(&mut code, 0x1000) { /// opcode.write(0, 0xff_u8); /// } /// /// assert_eq!(&code, b"\xff\x55\xff\x83\xEC*\x00\x80"); /// ``` pub fn iter_mut<'a>(self, bytes: &'a mut [u8], va: u64) -> IterMut<'a, X64> { <X64 as Isa>::iter_mut(bytes, va) } }