From a328d65ad490b64da8c87523cbbfe16050ba5bf6 Mon Sep 17 00:00:00 2001 From: PeterAlfredLee Date: Mon, 21 Apr 2025 15:18:10 +0800 Subject: [PATCH] allocate memory for the temporary buffer Allocate memory for the temporary buffer when paring numbers. This fixes CVE-2023-26819 --- cJSON.c | 37 ++++++++++++++++++++++++++++++++----- tests/misc_tests.c | 17 +++++++++++++++++ tests/parse_number.c | 20 ++++++++++++++++++++ 3 files changed, 69 insertions(+), 5 deletions(-) diff --git a/cJSON.c b/cJSON.c index d7c7236..ca824f0 100644 --- a/cJSON.c +++ b/cJSON.c @@ -308,9 +308,11 @@ static cJSON_bool parse_number(cJSON * const item, parse_buffer * const input_bu { double number = 0; unsigned char *after_end = NULL; - unsigned char number_c_string[64]; + unsigned char *number_c_string; unsigned char decimal_point = get_decimal_point(); size_t i = 0; + size_t number_string_length = 0; + cJSON_bool has_decimal_point = false; if ((input_buffer == NULL) || (input_buffer->content == NULL)) { @@ -320,7 +322,7 @@ static cJSON_bool parse_number(cJSON * const item, parse_buffer * const input_bu /* copy the number into a temporary buffer and replace '.' with the decimal point * of the current locale (for strtod) * This also takes care of '\0' not necessarily being available for marking the end of the input */ - for (i = 0; (i < (sizeof(number_c_string) - 1)) && can_access_at_index(input_buffer, i); i++) + for (i = 0; can_access_at_index(input_buffer, i); i++) { switch (buffer_at_offset(input_buffer)[i]) { @@ -338,11 +340,12 @@ static cJSON_bool parse_number(cJSON * const item, parse_buffer * const input_bu case '-': case 'e': case 'E': - number_c_string[i] = buffer_at_offset(input_buffer)[i]; + number_string_length++; break; case '.': - number_c_string[i] = decimal_point; + number_string_length++; + has_decimal_point = true; break; default: @@ -350,11 +353,33 @@ static cJSON_bool parse_number(cJSON * const item, parse_buffer * const input_bu } } loop_end: - number_c_string[i] = '\0'; + /* malloc for temporary buffer, add 1 for '\0' */ + number_c_string = (unsigned char *) input_buffer->hooks.allocate(number_string_length + 1); + if (number_c_string == NULL) + { + return false; /* allocation failure */ + } + + memcpy(number_c_string, buffer_at_offset(input_buffer), number_string_length); + number_c_string[number_string_length] = '\0'; + + if (has_decimal_point) + { + for (i = 0; i < number_string_length; i++) + { + if (number_c_string[i] == '.') + { + /* replace '.' with the decimal point of the current locale (for strtod) */ + number_c_string[i] = decimal_point; + } + } + } number = strtod((const char*)number_c_string, (char**)&after_end); if (number_c_string == after_end) { + /* free the temporary buffer */ + input_buffer->hooks.deallocate(number_c_string); return false; /* parse_error */ } @@ -377,6 +402,8 @@ loop_end: item->type = cJSON_Number; input_buffer->offset += (size_t)(after_end - number_c_string); + /* free the temporary buffer */ + input_buffer->hooks.deallocate(number_c_string); return true; } diff --git a/tests/misc_tests.c b/tests/misc_tests.c index a96c2fd..7c61647 100644 --- a/tests/misc_tests.c +++ b/tests/misc_tests.c @@ -782,6 +782,22 @@ static void cjson_set_bool_value_must_not_break_objects(void) cJSON_Delete(sobj); } +static void cjson_parse_big_numbers_should_not_report_error(void) +{ + cJSON *valid_big_number_json_object1 = cJSON_Parse("{\"a\": true, \"b\": [ null,9999999999999999999999999999999999999999999999912345678901234567]}"); + cJSON *valid_big_number_json_object2 = cJSON_Parse("{\"a\": true, \"b\": [ null,999999999999999999999999999999999999999999999991234567890.1234567E3]}"); + const char *invalid_big_number_json1 = "{\"a\": true, \"b\": [ null,99999999999999999999999999999999999999999999999.1234567890.1234567]}"; + const char *invalid_big_number_json2 = "{\"a\": true, \"b\": [ null,99999999999999999999999999999999999999999999999E1234567890e1234567]}"; + + TEST_ASSERT_NOT_NULL(valid_big_number_json_object1); + TEST_ASSERT_NOT_NULL(valid_big_number_json_object2); + TEST_ASSERT_NULL_MESSAGE(cJSON_Parse(invalid_big_number_json1), "Invalid big number JSONs should not be parsed."); + TEST_ASSERT_NULL_MESSAGE(cJSON_Parse(invalid_big_number_json2), "Invalid big number JSONs should not be parsed."); + + cJSON_Delete(valid_big_number_json_object1); + cJSON_Delete(valid_big_number_json_object2); +} + int CJSON_CDECL main(void) { UNITY_BEGIN(); @@ -815,6 +831,7 @@ int CJSON_CDECL main(void) RUN_TEST(cjson_delete_item_from_array_should_not_broken_list_structure); RUN_TEST(cjson_set_valuestring_to_object_should_not_leak_memory); RUN_TEST(cjson_set_bool_value_must_not_break_objects); + RUN_TEST(cjson_parse_big_numbers_should_not_report_error); return UNITY_END(); } diff --git a/tests/parse_number.c b/tests/parse_number.c index 4cb72ec..defda4a 100644 --- a/tests/parse_number.c +++ b/tests/parse_number.c @@ -48,6 +48,7 @@ static void assert_parse_number(const char *string, int integer, double real) parse_buffer buffer = { 0, 0, 0, 0, { 0, 0, 0 } }; buffer.content = (const unsigned char*)string; buffer.length = strlen(string) + sizeof(""); + buffer.hooks = global_hooks; TEST_ASSERT_TRUE(parse_number(item, &buffer)); assert_is_number(item); @@ -55,6 +56,17 @@ static void assert_parse_number(const char *string, int integer, double real) TEST_ASSERT_EQUAL_DOUBLE(real, item->valuedouble); } +static void assert_parse_big_number(const char *string) +{ + parse_buffer buffer = { 0, 0, 0, 0, { 0, 0, 0 } }; + buffer.content = (const unsigned char*)string; + buffer.length = strlen(string) + sizeof(""); + buffer.hooks = global_hooks; + + TEST_ASSERT_TRUE(parse_number(item, &buffer)); + assert_is_number(item); +} + static void parse_number_should_parse_zero(void) { assert_parse_number("0", 0, 0); @@ -96,6 +108,13 @@ static void parse_number_should_parse_negative_reals(void) assert_parse_number("-123e-128", 0, -123e-128); } +static void parse_number_should_parse_big_numbers(void) +{ + assert_parse_big_number("9999999999999999999999999999999999999999999999912345678901234567"); + assert_parse_big_number("9999999999999999999999999999999999999999999999912345678901234567E10"); + assert_parse_big_number("999999999999999999999999999999999999999999999991234567890.1234567"); +} + int CJSON_CDECL main(void) { /* initialize cJSON item */ @@ -106,5 +125,6 @@ int CJSON_CDECL main(void) RUN_TEST(parse_number_should_parse_positive_integers); RUN_TEST(parse_number_should_parse_positive_reals); RUN_TEST(parse_number_should_parse_negative_reals); + RUN_TEST(parse_number_should_parse_big_numbers); return UNITY_END(); }