[feat] plt hook inject

01/project-hbj-hook/src/asm.rs

@@ -0,0 +1,12 @@
+
+use iced_x86::code_asm::asm_traits::CodeAsmJmp;
+use iced_x86::{Instruction, code_asm::*};
+
+pub fn assemble<F>(addr: u64, op: F) -> Result<Vec<u8>, Box<dyn std::error::Error>>
+where
+    F: Fn(&mut CodeAssembler) -> Result<(), Box<dyn std::error::Error>>,
+{
+    let mut asm = CodeAssembler::new(64)?;
+    _ = op(&mut asm);
+    Ok(asm.assemble(addr)?)
+}

01/project-hbj-hook/src/elf.rs

@@ -1,4 +1,7 @@
-use anyhow::{Context, bail};
+
+// elf.rs
+
+use anyhow::{Context};
 use goblin::elf::{Elf, ProgramHeader, Sym, program_header::PT_DYNAMIC, program_header::PT_LOAD, reloc::R_X86_64_JUMP_SLOT, Reloc};
 use memmap2::Mmap;
 use std::fs::File;
@@ -108,4 +111,9 @@ impl ExecuteLinkFile {
 
         Ok(str.to_owned())
     }
+    
+    pub fn get_e_type(&self) -> u16
+    {
+        self.borrow_elf().header.e_type
+    }
 }

01/project-hbj-hook/src/main.rs

@@ -1,9 +1,15 @@
-use crate::elf::ExecuteLinkFile;
+use std::error::Error;
+use std::ffi::CString;
+use anyhow::Context;
+use iced_x86::code_asm::*;
 use crate::map::MemoryMap;
 use crate::processes::{get_pid_by_name, Process};
-use anyhow::Context;
 use nix::unistd::Pid;
-use std::fs;
+
+use libc::user_regs_struct;
+use nix::sys::ptrace;
+
+use crate::asm::assemble;
 
 const GREEN: &str = "\x1b[32m";
 const RESET: &str = "\x1b[0m";
@@ -12,8 +18,61 @@ mod disassembly;
 mod elf;
 mod map;
 mod processes;
+mod asm;
 
-fn main() -> Result<(), Box<dyn std::error::Error>> {
+pub fn plt_hook<F>(proc: &Process, map: &MemoryMap, symbol: &str, payload: F)
+    -> Result<(), Box<dyn Error>>
+where
+    F: Fn(&Process, u64, u64) -> Vec<u8>
+{
+    let bias = map.module_base_address(&proc.get_exe()?).unwrap_or(0);
+    let got_item_ptr = proc.find_got_pointer_plt(symbol).context("Unable to find symbol")?;
+
+    println!("{GREEN}[memory map]{RESET} Bias is {:#016x}", bias);
+
+    let got_item_byte: [u8; 8] = proc.read_memory_vm(got_item_ptr as usize, 8)?
+        .try_into()
+        .map_err(|_| "Failed to convert Vec to array")?;
+    let got_item = u64::from_le_bytes(got_item_byte);
+    println!(
+        "{GREEN}[memory map]{RESET} got_item = {:#016x}", got_item
+    );
+
+    // Alloc r-x private memory
+    let regs = ptrace::getregs(proc.get_pid())?;
+    let r = proc.execute_once_inplace(&assemble(regs.rip as u64, |asm| {
+        asm.mov(rax, 9u64)?; // Syscall 9 (mmap)
+
+        asm.mov(rdi, 0u64)?; // Addr
+        asm.mov(rsi, 0x1000u64)?; // Length, we alloc a page (4K)
+        asm.mov(
+            rdx,
+            (libc::PROT_READ | libc::PROT_EXEC) as u64,
+        )?; // Set protect to rwx
+        asm.mov(r10, (libc::MAP_PRIVATE | libc::MAP_ANONYMOUS) as u64)?; // Private and anonymous
+        asm.mov(r8, 01i64)?; // Fd (-1 because we want anonymous)
+        asm.mov(r9, 0u64)?; // Offset
+
+        asm.syscall()?; // Syscall interrupt
+        Ok(())
+    })?)?;
+
+    let page_addr = r.rax as u64;
+    println!("{GREEN}[trace]{RESET} allocated page is at {:#016x}", page_addr);
+
+    let payload = payload(&proc, page_addr, got_item);
+    if payload.len() > 0x1000 { return Err(Box::<dyn Error>::from("payload exceeds 0x1000 bytes")); }
+
+    proc.write_memory_ptrace(page_addr as usize, &payload)?;
+    println!("{GREEN}[trace]{RESET} wrote {} bytes of instructions/data to {:#016x}", payload.len(), page_addr);
+    proc.write_memory_ptrace(got_item_ptr as usize, &page_addr.to_le_bytes())?;
+    println!("{GREEN}[trace]{RESET} rewrote got item at {:#016x} to {:#016x}, old value is {:#016x}",
+        got_item_ptr, page_addr, got_item);
+
+    Ok(())
+}
+
+fn main() -> Result<(), Box<dyn Error>> {
     // Find our target program
     let pid = Pid::from_raw(get_pid_by_name("target")?);
     let process = Process::new(pid)?;
@@ -27,23 +86,64 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     }
 
     let map = MemoryMap::new(&lines);
-    let bias = map.module_base_address(&exe).unwrap_or(0);
-    let write_got = process.find_got_pointer_plt("write").unwrap_or(0);
 
-    println!("{GREEN}[memory map]{RESET} Bias is {:#016x}", bias);
+    let seg_x = map.first_exec_segment(&exe).context("Can't find first exec segment")?;
-    println!("{GREEN}[memory map]{RESET} pointer to write is at {:#016x}", write_got);
 
-    let got_write_vec: [u8; 8] = process.read_memory_vm(write_got as usize, 8)?
+    ptrace::attach(pid)?;
-        .try_into()
+    process.wait();
-        .map_err(|_| "Failed to convert Vec to array")?;
+    ptrace::step(pid, None)?;
-    let got_write_addr = u64::from_le_bytes(got_write_vec);
+    process.wait();
-    let real_write_addr =
-        process.find_remote_proc("/usr/lib/libc.so.6", "write").context("Failed to find write.")?;
 
-    println!(
+    // Save context
-        "{GREEN}[memory map]{RESET} real_write_addr = {:#016x}, got_write_addr = {:#016x}",
+    let regs = ptrace::getregs(pid)?; // Save current registers
-        real_write_addr, got_write_addr
+
-    );
+    ptrace::setregs(
+        pid,
+        user_regs_struct {
+            rip: seg_x.0,
+            ..regs
+        },
+    )?;
+
+    // Do inject here
+
+    plt_hook(&process, &map, "write", |proc, addr, old| {
+        let inst = assemble(addr, |asm| {
+            asm.push(rdi)?;
+            asm.push(rsi)?;
+            asm.push(rdx)?;
+            asm.mov(rdi, 1u64)?;
+            asm.mov(rsi, addr + 0x800)?;
+            asm.mov(rdx, 7u64)?;
+            asm.call(old)?;
+            asm.pop(rdx)?;
+            asm.pop(rsi)?;
+            asm.pop(rdi)?;
+
+            asm.call(old)?;
+
+            asm.mov(rdi, 1u64)?;
+            asm.mov(rsi, addr + 0x810)?;
+            asm.mov(rdx, 2u64)?;
+            asm.call(old)?;
+
+            asm.ret()?;
+            Ok(())
+        }).unwrap();
+
+        let mut payload = Vec::from([0u8; 0x1000]);
+        payload.splice(0..inst.len(), inst);
+        payload.splice(0x800..(0x800 + 7), Vec::from("[hook] ".as_bytes()));
+        payload.splice(0x810..(0x810 + 2), Vec::from("\r\n".as_bytes()));
+
+        return payload;
+    })?;
+
+    // End inject logics
+
+    // Restore context
+    ptrace::setregs(pid, regs)?;
+    ptrace::detach(pid, None)?;
     
     Ok(())
 }

01/project-hbj-hook/src/map.rs

@@ -1,3 +1,6 @@
+
+// map.rs
+
 use crate::elf::ExecuteLinkFile;
 
 #[derive(Debug, Clone)]
@@ -81,15 +84,21 @@ impl MemoryMap {
             .map(|r| (r.start_addr, r.end_addr))
     }
 
-    pub fn module_base_address(&self, module: &str) -> Option<u64> {
+
+    pub fn module_base_address(
+        &self,
+        module: &str // Full path of module, like '/usr/lib/libc.so.6'
+    ) -> Option<u64> {
         let elf = ExecuteLinkFile::prase(&module).ok()?;
         let loads = elf.get_loads().ok()?;
-        let Some(first_load) = loads.first() else {
+        let Some(first_load) = loads.iter().find(|p| {
+            p.is_executable()
+        }) else {
             return None;
         };
 
         let Some(map_item) = self.regions.iter().find(|r| {
-            r.offset.unwrap_or(0) == first_load.p_offset && r.pathname.as_deref() == Some(module)
+            r.offset.unwrap_or(0) == first_load.p_offset && r.pathname.as_deref() == Some(module) && r.is_executable()
         }) else {
             return None;
         };

01/project-hbj-hook/src/processes.rs

@@ -1,3 +1,6 @@
+
+// processes.rs
+
 use std::collections::HashMap;
 use std::fs;
 
@@ -6,10 +9,14 @@ use nix::unistd::Pid;
 use std::error::Error;
 use std::ffi::CString;
 use std::io::{IoSliceMut, IoSlice};
+use goblin::elf64::{header, section_header};
+use iced_x86::code_asm::{r10, r8, r9, rax, rdi, rdx, rsi};
+use iced_x86::Instruction;
 use nix::sys::ptrace;
 
-use libc::{dlsym, RTLD_NEXT};
+use libc::{dlsym, user_regs_struct, RTLD_NEXT};
 use nix::sys::wait::{waitpid, WaitPidFlag, WaitStatus};
+use crate::asm::assemble;
 use crate::elf::ExecuteLinkFile;
 use crate::map::{MemoryMap};
 
@@ -72,7 +79,7 @@ impl Process
 
         let copy_len = usize::min(word_size - head_offset, data.len());
         bytes[head_offset..head_offset + copy_len].copy_from_slice(&data[..copy_len]);
-        let new_word = libc::c_long::from_ne_bytes(bytes);
+        let new_word = libc::c_long::from_le_bytes(bytes);
 
         ptrace::write(pid, aligned_addr as *mut libc::c_void, new_word)?;
         Ok(copy_len)
@@ -86,7 +93,7 @@ impl Process
     {
         let mut arr = [0u8; size_of::<libc::c_long>()];
         arr.copy_from_slice(data);
-        let val = libc::c_long::from_ne_bytes(arr);
+        let val = libc::c_long::from_le_bytes(arr);
         ptrace::write(pid, addr as *mut libc::c_void, val)?;
         Ok(size_of::<libc::c_long>())
     }
@@ -101,7 +108,7 @@ impl Process
         let orig_word = ptrace::read(pid, addr as *mut libc::c_void)?;
         let mut bytes = orig_word.to_ne_bytes();
         bytes[..data.len()].copy_from_slice(data);
-        let new_word = libc::c_long::from_ne_bytes(bytes);
+        let new_word = libc::c_long::from_le_bytes(bytes);
 
         ptrace::write(pid, addr as *mut libc::c_void, new_word)?;
         Ok(data.len())
@@ -238,15 +245,30 @@ impl Process
         Ok(written)
     }
 
-    pub fn find_remote_proc(&self, module: &str, symbol: &str) -> Option<u64>
+    pub fn find_remote_proc(
+        &self,
+        module: &str,  // Full path of module, like '/usr/lib/libc.so.6'
+        symbol: &str  // Symbol name, like 'printf'
+    ) -> Option<u64>
     {
-        let target_maps = fs::read_to_string(format!("/proc/{}/maps", self.pid)).ok()?;
-        let base = MemoryMap::new(&target_maps.lines().collect::<Vec<&str>>()).module_base_address(module)?;
-
         let elf = ExecuteLinkFile::prase(module).ok()?;
         let sym = elf.prase_dyn_sym(symbol).ok()?;
 
-        Some(sym.st_value + base)
+        let target_maps = fs::read_to_string(format!("/proc/{}/maps", self.pid)).ok()?;
+        let base = MemoryMap::new(&target_maps.lines().collect::<Vec<&str>>()).module_base_address(module)?;
+
+        let is_undefined = sym.st_shndx == section_header::SHN_UNDEF as usize;
+
+        if !is_undefined && sym.st_value != 0 {
+            return if elf.get_e_type() == header::ET_DYN {
+                Some(base + sym.st_value)
+            } else {
+                // ET_EXEC or others: assume st_value is absolute
+                Some(sym.st_value)
+            }
+        }
+
+        None
     }
 
     pub fn find_got_pointer_plt(&self, symbol: &str) -> Option<u64>
@@ -257,4 +279,28 @@ impl Process
         let r_sym = elf.get_rela_sym(symbol).ok()?;
         Some(r_sym.r_offset + self.map.module_base_address(&exe)?)
     }
+
+    pub fn execute_once_inplace(&self, payload: &[u8]) -> Result<user_regs_struct, Box<dyn Error>>
+    {
+        // Save context
+        let regs = ptrace::getregs(self.pid)?;
+        let buffer = self.read_memory_vm(regs.rip as usize, payload.len() + 1)?;
+        let instruction = [payload, &[0xccu8]].concat();
+
+
+        self.write_memory_ptrace(regs.rip as usize, &instruction)?;
+        println!("{GREEN}[trace]{RESET} write instructions to {:#016x}", regs.rip);
+
+        // Continue target
+        ptrace::cont(self.pid, None)?;
+        println!("{GREEN}[trace]{RESET} continue from {:#016x}", regs.rip);
+        self.wait();
+
+        let r = ptrace::getregs(self.pid)?;
+        println!("{GREEN}[trace]{RESET} int3 at {:#016x}", r.rip);
+
+        self.write_memory_ptrace(regs.rip as usize, &buffer)?;
+        ptrace::setregs(self.pid, regs)?;
+        Ok(r)
+    }
 }