[feat] add authenticated LAN transport and per-IP listeners

2026-10-25 14:47:00 +08:00 · 2026-10-25 00:54:10 +08:00
parent bd7f9505d9
commit 2445f79f92
12 changed files with 2681 additions and 3 deletions
@@ -0,0 +1,122 @@
+#include "lan_password.h"
+
+#include <openssl/core_names.h>
+#include <openssl/crypto.h>
+#include <openssl/kdf.h>
+#include <openssl/params.h>
+#include <openssl/rand.h>
+
+#include <array>
+#include <cstdint>
+#include <memory>
+#include <stdexcept>
+
+namespace crossdesk::lan {
+namespace {
+// An application format, with a hex salt in password_salt and hex digest here.
+// Only known work factors are accepted, bounding CPU/memory for corrupt data.
+constexpr char kPrefix[] = "argon2id$v=19$m=19456,t=2,p=1$";
+constexpr size_t kSaltBytes = 16, kDigestBytes = 32;
+
+bool ValidInput(const std::string& password) {
+  return password.size() <= 256 && password.find('\0') == std::string::npos;
+}
+
+std::string Hex(const unsigned char* data, size_t size) {
+  constexpr char digits[] = "0123456789abcdef";
+  std::string result;
+  result.reserve(size * 2);
+  for (size_t i = 0; i < size; ++i) {
+    result += digits[data[i] >> 4];
+    result += digits[data[i] & 15];
+  }
+  return result;
+}
+
+bool Unhex(const std::string& text, unsigned char* output, size_t size) {
+  if (text.size() != size * 2) return false;
+  auto digit = [](char c) -> int {
+    if (c >= '0' && c <= '9') return c - '0';
+    if (c >= 'a' && c <= 'f') return c - 'a' + 10;
+    if (c >= 'A' && c <= 'F') return c - 'A' + 10;
+    return -1;
+  };
+  for (size_t i = 0; i < size; ++i) {
+    const int hi = digit(text[i * 2]), lo = digit(text[i * 2 + 1]);
+    if (hi < 0 || lo < 0) return false;
+    output[i] = static_cast<unsigned char>((hi << 4) | lo);
+  }
+  return true;
+}
+
+using Kdf = std::unique_ptr<EVP_KDF, decltype(&EVP_KDF_free)>;
+using Context = std::unique_ptr<EVP_KDF_CTX, decltype(&EVP_KDF_CTX_free)>;
+
+std::optional<DevicePasswordRecord> Derive(
+    const std::string& password,
+    const std::array<unsigned char, kSaltBytes>& salt) {
+  Kdf kdf(EVP_KDF_fetch(nullptr, "ARGON2ID", nullptr), EVP_KDF_free);
+  if (!kdf) return std::nullopt;
+  Context context(EVP_KDF_CTX_new(kdf.get()), EVP_KDF_CTX_free);
+  if (!context) return std::nullopt;
+  uint32_t memory = 19456, iterations = 2, lanes = 1, threads = 1,
+           version = 0x13;
+  OSSL_PARAM params[] = {
+      OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_PASSWORD,
+                                        const_cast<char*>(password.data()),
+                                        password.size()),
+      OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT,
+                                        const_cast<unsigned char*>(salt.data()),
+                                        salt.size()),
+      OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_ARGON2_MEMCOST, &memory),
+      OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_ITER, &iterations),
+      OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_ARGON2_LANES, &lanes),
+      OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_THREADS, &threads),
+      OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_ARGON2_VERSION, &version),
+      OSSL_PARAM_construct_end()};
+  std::array<unsigned char, kDigestBytes> digest{};
+  if (EVP_KDF_derive(context.get(), digest.data(), digest.size(), params) != 1)
+    return std::nullopt;
+  DevicePasswordRecord result{Hex(salt.data(), salt.size()),
+                              kPrefix + Hex(digest.data(), digest.size())};
+  OPENSSL_cleanse(digest.data(), digest.size());
+  return result;
+}
+}  // namespace
+
+namespace DevicePassword {
+void CheckSupport() {
+  // Exercise the provider and parameters, not just algorithm discovery.
+  if (!Hash("startup-check"))
+    throw std::runtime_error(
+        "Argon2id or the secure random source is unavailable");
+}
+
+std::optional<DevicePasswordRecord> Hash(const std::string& password) {
+  if (!ValidInput(password)) return std::nullopt;
+  std::array<unsigned char, kSaltBytes> salt{};
+  if (RAND_bytes(salt.data(), salt.size()) != 1) return std::nullopt;
+  return Derive(password, salt);
+}
+
+bool IsCurrent(const DevicePasswordRecord& record) {
+  std::array<unsigned char, kSaltBytes> salt{};
+  std::array<unsigned char, kDigestBytes> digest{};
+  return record.hash.rfind(kPrefix, 0) == 0 &&
+         Unhex(record.salt, salt.data(), salt.size()) &&
+         Unhex(record.hash.substr(sizeof(kPrefix) - 1), digest.data(),
+               digest.size());
+}
+
+bool Verify(const DevicePasswordRecord& record, const std::string& password) {
+  if (!ValidInput(password) || !IsCurrent(record)) return false;
+  std::array<unsigned char, kSaltBytes> salt{};
+  Unhex(record.salt, salt.data(), salt.size());
+  const auto computed = Derive(password, salt);
+  return computed && computed->hash.size() == record.hash.size() &&
+         CRYPTO_memcmp(computed->hash.data(), record.hash.data(),
+                       computed->hash.size()) == 0;
+}
+}  // namespace DevicePassword
+
+}  // namespace crossdesk::lan