Rewrite cJSON_Minify, fixing buffer overflows, fixes #338

Also first tests for cJSON_Minify.
Thanks @bigric3 for reporting

tests/minify_tests.c

@@ -0,0 +1,167 @@
+/*
+  Copyright (c) 2009-2019 Dave Gamble and cJSON contributors
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+  THE SOFTWARE.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "unity/examples/unity_config.h"
+#include "unity/src/unity.h"
+#include "common.h"
+
+
+static void cjson_minify_should_not_overflow_buffer(void)
+{
+    char unclosed_multiline_comment[] = "/* bla";
+    char pending_escape[] = "\"\\";
+
+    cJSON_Minify(unclosed_multiline_comment);
+    TEST_ASSERT_EQUAL_STRING("", unclosed_multiline_comment);
+
+    cJSON_Minify(pending_escape);
+    TEST_ASSERT_EQUAL_STRING("\"\\", pending_escape);
+}
+
+static void cjson_minify_should_remove_single_line_comments(void)
+{
+    const char to_minify[] = "{// this is {} \"some kind\" of [] comment /*, don't you see\n}";
+
+    char* minified = (char*) malloc(sizeof(to_minify));
+    TEST_ASSERT_NOT_NULL(minified);
+    strcpy(minified, to_minify);
+
+    cJSON_Minify(minified);
+    TEST_ASSERT_EQUAL_STRING("{}", minified);
+
+    free(minified);
+}
+
+static void cjson_minify_should_remove_spaces(void)
+{
+    const char to_minify[] = "{ \"key\":\ttrue\r\n    }";
+
+    char* minified = (char*) malloc(sizeof(to_minify));
+    TEST_ASSERT_NOT_NULL(minified);
+    strcpy(minified, to_minify);
+
+    cJSON_Minify(minified);
+    TEST_ASSERT_EQUAL_STRING("{\"key\":true}", minified);
+
+    free(minified);
+}
+
+static void cjson_minify_should_remove_multiline_comments(void)
+{
+    const char to_minify[] = "{/* this is\n a /* multi\n //line \n {comment \"\\\" */}";
+
+    char* minified = (char*) malloc(sizeof(to_minify));
+    TEST_ASSERT_NOT_NULL(minified);
+    strcpy(minified, to_minify);
+
+    cJSON_Minify(minified);
+    TEST_ASSERT_EQUAL_STRING("{}", minified);
+
+    free(minified);
+}
+
+static void cjson_minify_should_not_modify_strings(void)
+{
+    const char to_minify[] = "\"this is a string \\\" \\t bla\"";
+
+    char* minified = (char*) malloc(sizeof(to_minify));
+    TEST_ASSERT_NOT_NULL(minified);
+    strcpy(minified, to_minify);
+
+    cJSON_Minify(minified);
+    TEST_ASSERT_EQUAL_STRING(to_minify, minified);
+
+    free(minified);
+}
+
+static void cjson_minify_should_minify_json(void) {
+    const char to_minify[] =
+            "{\n"
+            "    \"glossary\": { // comment\n"
+            "        \"title\": \"example glossary\",\n"
+            "  /* multi\n"
+            " line */\n"
+            "		\"GlossDiv\": {\n"
+            "            \"title\": \"S\",\n"
+            "			\"GlossList\": {\n"
+            "                \"GlossEntry\": {\n"
+            "                    \"ID\": \"SGML\",\n"
+            "					\"SortAs\": \"SGML\",\n"
+            "					\"Acronym\": \"SGML\",\n"
+            "					\"Abbrev\": \"ISO 8879:1986\",\n"
+            "					\"GlossDef\": {\n"
+            "						\"GlossSeeAlso\": [\"GML\", \"XML\"]\n"
+            "                    },\n"
+            "					\"GlossSee\": \"markup\"\n"
+            "                }\n"
+            "            }\n"
+            "        }\n"
+            "    }\n"
+            "}";
+    const char* minified =
+            "{"
+            "\"glossary\":{"
+            "\"title\":\"example glossary\","
+            "\"GlossDiv\":{"
+            "\"title\":\"S\","
+            "\"GlossList\":{"
+            "\"GlossEntry\":{"
+            "\"ID\":\"SGML\","
+            "\"SortAs\":\"SGML\","
+            "\"Acronym\":\"SGML\","
+            "\"Abbrev\":\"ISO 8879:1986\","
+            "\"GlossDef\":{"
+            "\"GlossSeeAlso\":[\"GML\",\"XML\"]"
+            "},"
+            "\"GlossSee\":\"markup\""
+            "}"
+            "}"
+            "}"
+            "}"
+            "}";
+
+    char *buffer = (char*) malloc(sizeof(to_minify));
+    strcpy(buffer, to_minify);
+
+    cJSON_Minify(buffer);
+    TEST_ASSERT_EQUAL_STRING(minified, buffer);
+
+    free(buffer);
+}
+
+int CJSON_CDECL main(void)
+{
+    UNITY_BEGIN();
+
+    RUN_TEST(cjson_minify_should_not_overflow_buffer);
+    RUN_TEST(cjson_minify_should_minify_json);
+    RUN_TEST(cjson_minify_should_remove_single_line_comments);
+    RUN_TEST(cjson_minify_should_remove_multiline_comments);
+    RUN_TEST(cjson_minify_should_remove_spaces);
+    RUN_TEST(cjson_minify_should_not_modify_strings);
+
+    return UNITY_END();
+}