Improve FakeTLS server-flight fidelity and macOS portability

src/tls_front/tests/emulator_profile_fidelity_security_tests.rs

@@ -0,0 +1,95 @@
+use std::time::SystemTime;
+
+use crate::crypto::SecureRandom;
+use crate::protocol::constants::{
+    TLS_RECORD_APPLICATION, TLS_RECORD_CHANGE_CIPHER, TLS_RECORD_HANDSHAKE,
+};
+use crate::tls_front::emulator::build_emulated_server_hello;
+use crate::tls_front::types::{
+    CachedTlsData, ParsedServerHello, TlsBehaviorProfile, TlsProfileSource,
+};
+
+fn make_cached() -> CachedTlsData {
+    CachedTlsData {
+        server_hello_template: ParsedServerHello {
+            version: [0x03, 0x03],
+            random: [0u8; 32],
+            session_id: Vec::new(),
+            cipher_suite: [0x13, 0x01],
+            compression: 0,
+            extensions: Vec::new(),
+        },
+        cert_info: None,
+        cert_payload: None,
+        app_data_records_sizes: vec![1200, 900, 220, 180],
+        total_app_data_len: 2500,
+        behavior_profile: TlsBehaviorProfile {
+            change_cipher_spec_count: 2,
+            app_data_record_sizes: vec![1200, 900],
+            ticket_record_sizes: vec![220, 180],
+            source: TlsProfileSource::Merged,
+        },
+        fetched_at: SystemTime::now(),
+        domain: "example.com".to_string(),
+    }
+}
+
+fn record_lengths_by_type(response: &[u8], wanted_type: u8) -> Vec<usize> {
+    let mut out = Vec::new();
+    let mut pos = 0usize;
+    while pos + 5 <= response.len() {
+        let record_type = response[pos];
+        let record_len = u16::from_be_bytes([response[pos + 3], response[pos + 4]]) as usize;
+        if pos + 5 + record_len > response.len() {
+            break;
+        }
+        if record_type == wanted_type {
+            out.push(record_len);
+        }
+        pos += 5 + record_len;
+    }
+    out
+}
+
+#[test]
+fn emulated_server_hello_replays_profile_change_cipher_spec_count() {
+    let cached = make_cached();
+    let rng = SecureRandom::new();
+
+    let response = build_emulated_server_hello(
+        b"secret",
+        &[0x71; 32],
+        &[0x72; 16],
+        &cached,
+        false,
+        &rng,
+        None,
+        0,
+    );
+
+    assert_eq!(response[0], TLS_RECORD_HANDSHAKE);
+    let ccs_records = record_lengths_by_type(&response, TLS_RECORD_CHANGE_CIPHER);
+    assert_eq!(ccs_records.len(), 2);
+    assert!(ccs_records.iter().all(|len| *len == 1));
+}
+
+#[test]
+fn emulated_server_hello_replays_profile_ticket_tail_lengths() {
+    let cached = make_cached();
+    let rng = SecureRandom::new();
+
+    let response = build_emulated_server_hello(
+        b"secret",
+        &[0x81; 32],
+        &[0x82; 16],
+        &cached,
+        false,
+        &rng,
+        None,
+        0,
+    );
+
+    let app_records = record_lengths_by_type(&response, TLS_RECORD_APPLICATION);
+    assert!(app_records.len() >= 4);
+    assert_eq!(&app_records[app_records.len() - 2..], &[220, 180]);
+}