[英]How to execute raw instructions from a memory buffer in Rust?
I'm attempting to make a buffer of memory executable, then execute it in Rust. 我试图使内存缓冲区可执行,然后在Rust中执行它。 I've gotten all the way until I need to cast the raw executable bytes as code/instructions.
我已经一路过关斩将,直到需要将原始的可执行字节转换为代码/指令为止。 You can see a working example in C below.
您可以在下面的C中看到一个有效的示例 。
Extra details: 额外详情:
unsigned char code[] = {
0x55, // push %rbp
0x48, 0x89, 0xe5, // mov %rsp,%rbp
0xb8, 0x37, 0x00, 0x00, 0x00, // mov $0x37,%eax
0xc9, // leaveq
0xc3 // retq
};
void reflect(const unsigned char *code) {
void *buf;
/* copy code to executable buffer */
buf = mmap(0, sizeof(code), PROT_READ|PROT_WRITE|PROT_EXEC,MAP_PRIVATE|MAP_ANON,-1,0);
memcpy(buf, code, sizeof(code));
((void (*) (void))buf)();
}
extern crate mmap;
use mmap::{MapOption, MemoryMap};
unsafe fn reflect(instructions: &[u8]) {
let map = MemoryMap::new(
instructions.len(),
&[
MapOption::MapAddr(0 as *mut u8),
MapOption::MapOffset(0),
MapOption::MapFd(-1),
MapOption::MapReadable,
MapOption::MapWritable,
MapOption::MapExecutable,
MapOption::MapNonStandardFlags(libc::MAP_ANON),
MapOption::MapNonStandardFlags(libc::MAP_PRIVATE),
],
)
.unwrap();
std::ptr::copy(instructions.as_ptr(), map.data(), instructions.len());
// How to cast into extern "C" fn() ?
}
Use mem::transmute
to cast a raw pointer to a function pointer type. 使用
mem::transmute
将原始指针转换为函数指针类型。
use std::mem;
let func: unsafe extern "C" fn() = mem::transmute(map.data());
func();
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