From 7b347366189c47a03a298fc782f4e3de2b2c5c42 Mon Sep 17 00:00:00 2001
From: sangge <2251250136@qq.com>
Date: Wed, 15 Oct 2025 16:29:24 +0800
Subject: [PATCH] feat: finish p32

---
 Cargo.lock               |  14 ++++
 problems/p32/Cargo.toml  |  14 ++++
 problems/p32/src/main.rs | 143 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 171 insertions(+)
 create mode 100644 problems/p32/Cargo.toml
 create mode 100644 problems/p32/src/main.rs

diff --git a/Cargo.lock b/Cargo.lock
index b85fbaa..c9ae358 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1052,6 +1052,20 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "p32"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "axum",
+ "common",
+ "hex",
+ "rand",
+ "reqwest",
+ "serde",
+ "tokio",
+]
+
 [[package]]
 name = "p33"
 version = "0.1.0"
diff --git a/problems/p32/Cargo.toml b/problems/p32/Cargo.toml
new file mode 100644
index 0000000..84839c1
--- /dev/null
+++ b/problems/p32/Cargo.toml
@@ -0,0 +1,14 @@
+[package]
+name = "p32"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+reqwest = { workspace = true }
+tokio = { workspace = true }
+axum = { workspace = true }
+serde = { workspace = true }
+common = { path = "../../common/" }
+hex = { workspace = true }
+rand = { workspace = true }
+anyhow = { workspace = true }
diff --git a/problems/p32/src/main.rs b/problems/p32/src/main.rs
new file mode 100644
index 0000000..61cdf23
--- /dev/null
+++ b/problems/p32/src/main.rs
@@ -0,0 +1,143 @@
+use std::time::{Duration, Instant};
+
+use common::sha1;
+
+use anyhow::Result;
+use axum::{Router, extract::Query, http::StatusCode, routing::get};
+use rand::Rng;
+use serde::Deserialize;
+use std::sync::LazyLock;
+use tokio::time::sleep;
+
+static HMAC_KEY: LazyLock<[u8; 20]> = LazyLock::new(|| {
+    // 生成随机密钥
+    let mut rng = rand::rng();
+    let key: [u8; 20] = rng.random();
+    key
+});
+
+#[derive(Deserialize)]
+struct Params {
+    file: String,
+    signature: String,
+}
+
+async fn verify_handler(Query(params): Query<Params>) -> StatusCode {
+    let my_signature = hmac_sha1(&*HMAC_KEY, params.file.as_bytes());
+
+    let provided_signature = match hex::decode(&params.signature) {
+        Ok(bytes) => bytes,
+        Err(e) => {
+            eprintln!("Hex decode error: {:?}", e);
+            return StatusCode::BAD_REQUEST;
+        }
+    };
+
+    match insecure_compare(&my_signature, &provided_signature).await {
+        true => StatusCode::OK,
+        false => StatusCode::INTERNAL_SERVER_ERROR,
+    }
+}
+
+async fn insecure_compare(a: &[u8], b: &[u8]) -> bool {
+    if a.len() != b.len() {
+        return false;
+    }
+    for i in 0..a.len() {
+        if a[i] != b[i] {
+            return false;
+        }
+        sleep(Duration::from_millis(5)).await;
+    }
+    true
+}
+
+fn hmac_sha1(key: &[u8], message: &[u8]) -> [u8; 20] {
+    let mut key = match key.len() {
+        0..=64 => key.to_vec(),
+        _ => sha1(key).to_vec(),
+    };
+    key.extend(vec![0; 64 - key.len()]);
+    let mut part_1 = key.iter().map(|x| x ^ 0x5c).collect::<Vec<u8>>();
+    let mut part_2_input = key.iter().map(|x| x ^ 0x36).collect::<Vec<u8>>();
+    part_2_input.extend(message);
+    let part_2 = sha1(&part_2_input);
+    part_1.extend(part_2);
+    sha1(&part_1)
+}
+#[test]
+fn test_hmac_sha1() {
+    let output = hmac_sha1("123".as_bytes(), "helloworld".as_bytes());
+    let output = hex::encode(output);
+    let correct = "8849fb5557760d35f19e2100aa250bfb97152bd9";
+    assert_eq!(output, correct);
+}
+
+async fn start_attack() -> Result<()> {
+    let mut signature = vec![0u8; 20];
+    let mut pos = 0;
+    let mut last_max_time = Duration::from_millis(0);
+    let min_time_increase = Duration::from_millis(1); // 最小耗时增量阈值
+
+    while pos < 20 {
+        let mut max_time = Duration::from_millis(0);
+        let mut best_byte = 0u8;
+
+        for byte in 0x00..=0xff {
+            signature[pos] = byte;
+            let url = format!(
+                "http://localhost:3000/verify?file={}&signature={}",
+                "helloworld",
+                hex::encode(&signature)
+            );
+            let start = Instant::now();
+            let status = reqwest::get(&url).await?.status();
+            let elapsed = start.elapsed();
+
+            if status == StatusCode::OK {
+                println!("✓ 找到完整签名: {}", hex::encode(&signature));
+                return Ok(());
+            }
+
+            if elapsed > max_time {
+                max_time = elapsed;
+                best_byte = byte;
+            }
+        }
+
+        signature[pos] = best_byte;
+        println!(
+            "位置 {} 确定为: {:02x}, 耗时: {:?}",
+            pos, best_byte, max_time
+        );
+
+        // 检查耗时是否有足够增长
+        if pos > 0 && max_time.saturating_sub(last_max_time) < min_time_increase {
+            println!("⚠ 耗时增长不足，回退1位重试",);
+            pos = pos.saturating_sub(1);
+            last_max_time = Duration::from_millis(0); // 重置基准
+            continue;
+        }
+
+        last_max_time = max_time;
+        pos += 1;
+    }
+    Ok(())
+}
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    let app = Router::new().route("/verify", get(verify_handler));
+
+    let listener = tokio::net::TcpListener::bind("127.0.0.1:3000").await?;
+
+    dbg!(hex::encode(*HMAC_KEY));
+
+    // 后台启动服务器
+    tokio::spawn(async move {
+        axum::serve(listener, app).await.unwrap();
+    });
+    start_attack().await?;
+    Ok(())
+}
+