From 36beaa454a5f21b737efbdf4d626de79ed1bec5e Mon Sep 17 00:00:00 2001
From: abba23 <abba23@users.noreply.github.com>
Date: Wed, 5 May 2021 11:01:06 +0200
Subject: [PATCH] Remove redhook dependency

---
 Cargo.toml |  4 +--
 src/lib.rs | 86 +++++++++++++++++++++++++++++++++---------------------
 2 files changed, 55 insertions(+), 35 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index e3909d6..cb2c9bf 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,15 +8,15 @@ edition = "2018"
 [dependencies]
 lazy_static = "*"
 libc = "*"
-redhook = "*"
 regex = "*"
 serde = { version = "*", features = ["derive"] }
 toml = "*"
 
 [lib]
 name = "spotifyadblock"
-crate_type = ["dylib"]
+crate_type = ["cdylib"]
 
 [profile.release]
 lto = true
+opt-level = 3
 panic = "abort"
diff --git a/src/lib.rs b/src/lib.rs
index 39f2b40..5a0d7bd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,17 +4,37 @@ use cef::{
     _cef_request_context_t, _cef_request_t, _cef_urlrequest_client_t, cef_string_userfree_utf16_free, cef_urlrequest_t,
 };
 use lazy_static::lazy_static;
-use libc::{addrinfo, c_char, EAI_FAIL};
-use redhook::{hook, real};
+use libc::{addrinfo, c_char, dlsym, EAI_FAIL, RTLD_NEXT};
 use regex::Regex;
 use serde::Deserialize;
 use std::ffi::CStr;
 use std::fs::read_to_string;
+use std::mem;
 use std::path::PathBuf;
 use std::ptr::null;
 use std::slice::from_raw_parts;
 use std::string::String;
 
+macro_rules! hook {
+    ($function_name:ident($($parameter_name:ident: $parameter_type:ty),*) -> $return_type:ty => $new_function_name:ident $body:block) => {
+        lazy_static! {
+            static ref $new_function_name: fn($($parameter_type),*) -> $return_type = unsafe {
+                let function_name = CStr::from_bytes_with_nul(concat!(stringify!($function_name), "\0").as_bytes()).unwrap();
+                let function_pointer = dlsym(RTLD_NEXT, function_name.as_ptr());
+                if function_pointer.is_null() {
+                    panic!("[*] Error: Unable to find function \"{}\"", stringify!($function_name));
+                }
+                mem::transmute(function_pointer)
+            };
+        }
+
+        #[no_mangle]
+        pub unsafe extern "C" fn $function_name($($parameter_name: $parameter_type),*) -> $return_type {
+            $body
+        }
+    }
+}
+
 #[derive(Deserialize)]
 struct Config {
     allowlist: Vec<String>,
@@ -55,6 +75,37 @@ lazy_static! {
     };
 }
 
+hook! {
+    getaddrinfo(node: *const c_char, service: *const c_char, hints: *const addrinfo, res: *const *const addrinfo) -> i32 => REAL_GETADDRINFO {
+        let domain = CStr::from_ptr(node).to_str().unwrap();
+
+        if listed(domain, &CONFIG.allowlist) {
+            println!("[+] getaddrinfo:\t\t {}", domain);
+            REAL_GETADDRINFO(node, service, hints, res)
+        } else {
+            println!("[-] getaddrinfo:\t\t {}", domain);
+            EAI_FAIL
+        }
+    }
+}
+
+hook! {
+    cef_urlrequest_create(request: *mut _cef_request_t, client: *const _cef_urlrequest_client_t, request_context: *const _cef_request_context_t) -> *const cef_urlrequest_t => REAL_CEF_URLREQUEST_CREATE {
+        let url_cef = (*request).get_url.unwrap()(request);
+        let url_utf16 = from_raw_parts((*url_cef).str_, (*url_cef).length as usize);
+        let url = String::from_utf16(url_utf16).unwrap();
+        cef_string_userfree_utf16_free(url_cef);
+
+        if listed(&url, &CONFIG.denylist) {
+            println!("[-] cef_urlrequest_create:\t {}", url);
+            null()
+        } else {
+            println!("[+] cef_urlrequest_create:\t {}", url);
+            REAL_CEF_URLREQUEST_CREATE(request, client, request_context)
+        }
+    }
+}
+
 fn listed(element: &str, regex_list: &Vec<String>) -> bool {
     for regex_string in regex_list {
         // TODO: only generate each regex once outside of loop
@@ -71,34 +122,3 @@ fn listed(element: &str, regex_list: &Vec<String>) -> bool {
     }
     false
 }
-
-hook! {
-    unsafe fn getaddrinfo(node: *const c_char, service: *const c_char, hints: *const addrinfo, res: *const *const addrinfo) -> i32 => _getaddrinfo {
-        let domain = CStr::from_ptr(node).to_str().unwrap();
-
-        if listed(domain, &CONFIG.allowlist) {
-            println!("[+] getaddrinfo:\t\t {}", domain);
-            real!(getaddrinfo)(node, service, hints, res)
-        } else {
-            println!("[-] getaddrinfo:\t\t {}", domain);
-            EAI_FAIL
-        }
-    }
-}
-
-hook! {
-    unsafe fn cef_urlrequest_create(request: *mut _cef_request_t, client: *const _cef_urlrequest_client_t, request_context: *const _cef_request_context_t) -> *const cef_urlrequest_t => _cef_urlrequest_create {
-        let url_cef = (*request).get_url.unwrap()(request);
-        let url_utf16 = from_raw_parts((*url_cef).str_, (*url_cef).length as usize);
-        let url = String::from_utf16(url_utf16).unwrap();
-        cef_string_userfree_utf16_free(url_cef);
-
-        if listed(&url, &CONFIG.denylist) {
-            println!("[-] cef_urlrequest_create:\t {}", url);
-            null()
-        } else {
-            println!("[+] cef_urlrequest_create:\t {}", url);
-            real!(cef_urlrequest_create)(request, client, request_context)
-        }
-    }
-}