From 61f0d683e047746d714adaf1d11d6736ee0c304b Mon Sep 17 00:00:00 2001 From: Niels Lohmann Date: Wed, 20 May 2026 22:08:45 +0200 Subject: [PATCH] :bug: avoid overflow Signed-off-by: Niels Lohmann --- include/nlohmann/detail/output/serializer.hpp | 9 ++++++--- single_include/nlohmann/json.hpp | 9 ++++++--- tests/src/unit-inspection.cpp | 6 ++++++ 3 files changed, 18 insertions(+), 6 deletions(-) diff --git a/include/nlohmann/detail/output/serializer.hpp b/include/nlohmann/detail/output/serializer.hpp index cdf0a9d7b..6e75aff43 100644 --- a/include/nlohmann/detail/output/serializer.hpp +++ b/include/nlohmann/detail/output/serializer.hpp @@ -128,7 +128,8 @@ class serializer const auto new_indent = current_indent + indent_step; if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent)) { - indent_string.resize(indent_string.size() * 2, indent_char); + indent_string.resize(std::max(indent_string.size() * 2, static_cast(new_indent)), indent_char); + JSON_ASSERT(indent_string.size() >= new_indent); } // first n-1 elements @@ -201,7 +202,8 @@ class serializer const auto new_indent = current_indent + indent_step; if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent)) { - indent_string.resize(indent_string.size() * 2, indent_char); + indent_string.resize(std::max(indent_string.size() * 2, static_cast(new_indent)), indent_char); + JSON_ASSERT(indent_string.size() >= new_indent); } // first n-1 elements @@ -262,7 +264,8 @@ class serializer const auto new_indent = current_indent + indent_step; if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent)) { - indent_string.resize(indent_string.size() * 2, indent_char); + indent_string.resize(std::max(indent_string.size() * 2, static_cast(new_indent)), indent_char); + JSON_ASSERT(indent_string.size() >= new_indent); } o->write_characters(indent_string.c_str(), new_indent); diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp index 3a7e6fbff..663883b12 100644 --- a/single_include/nlohmann/json.hpp +++ b/single_include/nlohmann/json.hpp @@ -19302,7 +19302,8 @@ class serializer const auto new_indent = current_indent + indent_step; if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent)) { - indent_string.resize(indent_string.size() * 2, indent_char); + indent_string.resize(std::max(indent_string.size() * 2, static_cast(new_indent)), indent_char); + JSON_ASSERT(indent_string.size() >= new_indent); } // first n-1 elements @@ -19375,7 +19376,8 @@ class serializer const auto new_indent = current_indent + indent_step; if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent)) { - indent_string.resize(indent_string.size() * 2, indent_char); + indent_string.resize(std::max(indent_string.size() * 2, static_cast(new_indent)), indent_char); + JSON_ASSERT(indent_string.size() >= new_indent); } // first n-1 elements @@ -19436,7 +19438,8 @@ class serializer const auto new_indent = current_indent + indent_step; if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent)) { - indent_string.resize(indent_string.size() * 2, indent_char); + indent_string.resize(std::max(indent_string.size() * 2, static_cast(new_indent)), indent_char); + JSON_ASSERT(indent_string.size() >= new_indent); } o->write_characters(indent_string.c_str(), new_indent); diff --git a/tests/src/unit-inspection.cpp b/tests/src/unit-inspection.cpp index 9d6d06e23..83349484e 100644 --- a/tests/src/unit-inspection.cpp +++ b/tests/src/unit-inspection.cpp @@ -254,6 +254,8 @@ TEST_CASE("object inspection") CHECK(j_array.dump(1024).size() == 25622); // check if right indentation symbol is used CHECK(j_array.dump(1024, '\t')[4096] == '\t'); + // check resize is large enough + CHECK(j_array.dump(10000).size() == 250022); } SECTION("object") @@ -263,6 +265,8 @@ TEST_CASE("object inspection") CHECK(j_object.dump(1024).size() == 25642); // check if right indentation symbol is used CHECK(j_object.dump(1024, '\t')[4096] == '\t'); + // check resize is large enough + CHECK(j_object.dump(10000).size() == 250042); } SECTION("binary") @@ -271,6 +275,8 @@ TEST_CASE("object inspection") // check right size after indentation triggering a resize CHECK(j_binary.dump(1024).size() == 2086); CHECK(j_binary.dump(1024, '\t')[1024] == '\t'); + // check resize is large enough + CHECK(j_binary.dump(10000).size() == 20038); } }