Add !!Con 2021 content

content/pages/bangbangcon2021/demo/src/main.rs

@@ -0,0 +1,35 @@
+use crate::things::*;
+use libc::*;
+use std::{mem, slice, str};
+mod things;
+
+use owoify::OwOifiable;
+static mut REAL_WRITE: Option<LibcWrite> = None;
+
+unsafe extern "C" fn write_owo(fd: i32, ptr: *const c_void, len: usize) -> isize {
+    let s = slice::from_raw_parts(ptr as *const _, len);
+    let s = str::from_utf8(s).unwrap();
+    let owoified = s.to_string().owoify();
+
+    REAL_WRITE.unwrap()(fd, owoified.as_ptr() as *const _, owoified.len());
+    len as isize
+}
+
+fn main() {
+    let addr = get_hex_from_cmdline();
+    let addr = (addr + 0x555555554000) as *mut usize;
+
+    unsafe {
+        REAL_WRITE = Some(mem::transmute(*addr));
+        mprotect(
+            (addr as usize & !(0x1000 - 1)) as *mut _,
+            0x1000,
+            PROT_READ | PROT_WRITE,
+        );
+        *addr = write_owo as usize;
+    }
+    let s = "hello !!con!!\n";
+    unsafe { write(1, s.as_ptr() as *const _, s.len()) };
+
+    println!("hello !!con!! from println");
+}

content/pages/bangbangcon2021/demo/src/things.rs

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+pub type LibcWrite = unsafe extern "C" fn(fd: i32, ptr: *const libc::c_void, len: usize) -> isize;
+pub fn get_hex_from_cmdline() -> usize {
+    usize::from_str_radix(&std::env::args().skip(1).next().unwrap(), 16).unwrap()
+}