checked_cast_to_or_throw

FAlbertDev · Sep 28, 2023 · 2312605 · 2312605
1 parent 6668d74
commit 2312605
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Showing 5 changed files with 18 additions and 9 deletions.
diff --git a/src/lib/pubkey/hss_lms/hss.cpp b/src/lib/pubkey/hss_lms/hss.cpp
@@ -90,8 +90,10 @@ HSS_LMS_Params::HSS_LMS_Params(std::string_view algo_params) {
       SCAN_Name scan_layer(scan.arg(i));
       BOTAN_ARG_CHECK(scan_layer.algo_name() == "HW", "Invalid name for layer parameters");
       BOTAN_ARG_CHECK(scan_layer.arg_count() == 2, "Invalid number of layer parameters");
-      const auto h = checked_cast_to<uint8_t>(scan_layer.arg_as_integer(0));
-      const auto w = checked_cast_to<uint8_t>(scan_layer.arg_as_integer(1));
+      const auto h =
+         checked_cast_to_or_throw<uint8_t, Invalid_Argument>(scan_layer.arg_as_integer(0), "Invalid parameter");
+      const auto w =
+         checked_cast_to_or_throw<uint8_t, Invalid_Argument>(scan_layer.arg_as_integer(1), "Invalid parameter");
       m_lms_lmots_params.push_back({LMS_Params::create_or_throw(hash, h), LMOTS_Params::create_or_throw(hash, w)});
    }
    m_max_sig_count = calc_max_sig_count();

diff --git a/src/lib/pubkey/hss_lms/lm_ots.cpp b/src/lib/pubkey/hss_lms/lm_ots.cpp
@@ -110,7 +110,7 @@ std::vector<uint8_t> gen_Q_with_cksm(const LMOTS_Params& params,
 }  // namespace
 
 LMOTS_Params LMOTS_Params::create_or_throw(LMOTS_Algorithm_Type type) {
-   uint8_t type_value = checked_cast_to<uint8_t>(type);
+   uint8_t type_value = checked_cast_to_or_throw<uint8_t, Decoding_Error>(type, "Unsupported LM-OTS algorithm type");
 
    if(type >= LMOTS_Algorithm_Type::SHA256_N32_W1 && type <= LMOTS_Algorithm_Type::SHA256_N32_W8) {
       uint8_t w = 1 << (type_value - checked_cast_to<uint8_t>(LMOTS_Algorithm_Type::SHA256_N32_W1));

diff --git a/src/lib/pubkey/hss_lms/lms.cpp b/src/lib/pubkey/hss_lms/lms.cpp
@@ -120,7 +120,7 @@ void lms_treehash(StrongSpan<LMS_Tree_Node> out_root,
 }  // namespace
 
 LMS_Params LMS_Params::create_or_throw(LMS_Algorithm_Type type) {
-   uint8_t type_value = checked_cast_to<uint8_t>(type);
+   uint8_t type_value = checked_cast_to_or_throw<uint8_t, Decoding_Error>(type, "Unsupported LMS algorithm type");
 
    if(type >= LMS_Algorithm_Type::SHA256_M32_H5 && type <= LMS_Algorithm_Type::SHA256_M32_H25) {
       uint8_t h = 5 * (type_value - checked_cast_to<uint8_t>(LMS_Algorithm_Type::SHA256_M32_H5) + 1);

diff --git a/src/lib/utils/safeint.h b/src/lib/utils/safeint.h
@@ -61,15 +61,20 @@ inline std::optional<size_t> checked_mul(size_t x, size_t y) {
    return z;
 }
 
-template <typename RT, typename AT>
-RT checked_cast_to(AT i) {
+template <typename RT, typename ExceptionType, typename AT>
+constexpr RT checked_cast_to_or_throw(AT i, std::string_view error_msg_on_fail) {
    RT c = static_cast<RT>(i);
    if(i != static_cast<AT>(c)) {
-      throw Internal_Error("Error during integer conversion");
+      throw ExceptionType(error_msg_on_fail);
    }
    return c;
 }
 
+template <typename RT, typename AT>
+constexpr RT checked_cast_to(AT i) {
+   return checked_cast_to_or_throw<RT, Internal_Error>(i, "Error during integer conversion");
+}
+
 #define BOTAN_CHECKED_ADD(x, y) checked_add(x, y, __FILE__, __LINE__)
 #define BOTAN_CHECKED_MUL(x, y) checked_mul(x, y)
 

diff --git a/src/tests/test_hss_lms.cpp b/src/tests/test_hss_lms.cpp
@@ -145,7 +145,8 @@ class HSS_LMS_Too_Short_Test final : public Test {
          for(size_t n = 0; n < sk_bytes.size(); ++n) {
             result.test_throws<Botan::Decoding_Error>("Partial private key invalid", [&]() {
                std::span<const uint8_t> partial_key = {sk_bytes.data(), n};
-               std::make_unique<Botan::HSS_LMS_PrivateKey>(partial_key);
+               Botan::HSS_LMS_PrivateKey key(partial_key);
+               BOTAN_UNUSED(key);
             });
          }
          return result;
@@ -163,7 +164,8 @@ class HSS_LMS_Too_Short_Test final : public Test {
          for(size_t n = 0; n < sk_bytes.size(); ++n) {
             result.test_throws<Botan::Decoding_Error>("Partial public key invalid", [&]() {
                std::span<const uint8_t> partial_key = {sk_bytes.data(), n};
-               std::make_unique<Botan::HSS_LMS_PublicKey>(partial_key);
+               Botan::HSS_LMS_PublicKey key(partial_key);
+               BOTAN_UNUSED(key);
             });
          }
          return result;