From 922d42bb0d08c154602dd9112da00d22d2b46579 Mon Sep 17 00:00:00 2001 From: Alex Chen Date: Fri, 13 Nov 2020 14:55:25 +0000 Subject: [PATCH] json: Fix a memleak in parse_pair() In qobject_type(), NULL is returned when the 'QObject' returned from parse_value() is not of QString type, and this 'QObject' memory will leaked. So we need to first cache the 'QObject' returned from parse_value(), and finally free 'QObject' memory at the end of the function. Also, we add a testcast about invalid dict key. The memleak stack is as follows: Direct leak of 32 byte(s) in 1 object(s) allocated from: #0 0xfffe4b3c34fb in __interceptor_malloc (/lib64/libasan.so.4+0xd34fb) #1 0xfffe4ae48aa3 in g_malloc (/lib64/libglib-2.0.so.0+0x58aa3) #2 0xaaab3557d9f7 in qnum_from_int qemu/qobject/qnum.c:25 #3 0xaaab35584d23 in parse_literal qemu/qobject/json-parser.c:511 #4 0xaaab35584d23 in parse_value qemu/qobject/json-parser.c:554 #5 0xaaab35583d77 in parse_pair qemu/qobject/json-parser.c:270 #6 0xaaab355845db in parse_object qemu/qobject/json-parser.c:327 #7 0xaaab355845db in parse_value qemu/qobject/json-parser.c:546 #8 0xaaab35585b1b in json_parser_parse qemu/qobject/json-parser.c:580 #9 0xaaab35583703 in json_message_process_token qemu/qobject/json-streamer.c:92 #10 0xaaab355ddccf in json_lexer_feed_char qemu/qobject/json-lexer.c:313 #11 0xaaab355de0eb in json_lexer_feed qemu/qobject/json-lexer.c:350 #12 0xaaab354aff67 in tcp_chr_read qemu/chardev/char-socket.c:525 #13 0xfffe4ae429db in g_main_context_dispatch (/lib64/libglib-2.0.so.0+0x529db) #14 0xfffe4ae42d8f (/lib64/libglib-2.0.so.0+0x52d8f) #15 0xfffe4ae430df in g_main_loop_run (/lib64/libglib-2.0.so.0+0x530df) #16 0xaaab34d70bff in iothread_run qemu/iothread.c:82 #17 0xaaab3559d71b in qemu_thread_start qemu/util/qemu-thread-posix.c:519 Fixes: 532fb5328473 ("qapi: Make more of qobject_to()") Reported-by: Euler Robot Signed-off-by: Alex Chen Signed-off-by: Chen Qun Signed-off-by: Markus Armbruster Message-Id: <20201113145525.85151-1-alex.chen@huawei.com> [Commit message tweaked] --- qobject/json-parser.c | 12 ++++++------ tests/check-qjson.c | 9 +++++++++ 2 files changed, 15 insertions(+), 6 deletions(-) diff --git a/qobject/json-parser.c b/qobject/json-parser.c index d083810d37..c0f521b56b 100644 --- a/qobject/json-parser.c +++ b/qobject/json-parser.c @@ -257,8 +257,9 @@ static JSONToken *parser_context_peek_token(JSONParserContext *ctxt) */ static int parse_pair(JSONParserContext *ctxt, QDict *dict) { + QObject *key_obj = NULL; + QString *key; QObject *value; - QString *key = NULL; JSONToken *peek, *token; peek = parser_context_peek_token(ctxt); @@ -267,7 +268,8 @@ static int parse_pair(JSONParserContext *ctxt, QDict *dict) goto out; } - key = qobject_to(QString, parse_value(ctxt)); + key_obj = parse_value(ctxt); + key = qobject_to(QString, key_obj); if (!key) { parse_error(ctxt, peek, "key is not a string in object"); goto out; @@ -297,13 +299,11 @@ static int parse_pair(JSONParserContext *ctxt, QDict *dict) qdict_put_obj(dict, qstring_get_str(key), value); - qobject_unref(key); - + qobject_unref(key_obj); return 0; out: - qobject_unref(key); - + qobject_unref(key_obj); return -1; } diff --git a/tests/check-qjson.c b/tests/check-qjson.c index 07a773e653..9a02079099 100644 --- a/tests/check-qjson.c +++ b/tests/check-qjson.c @@ -1415,6 +1415,14 @@ static void invalid_dict_comma(void) g_assert(obj == NULL); } +static void invalid_dict_key(void) +{ + Error *err = NULL; + QObject *obj = qobject_from_json("{32:'abc'}", &err); + error_free_or_abort(&err); + g_assert(obj == NULL); +} + static void unterminated_literal(void) { Error *err = NULL; @@ -1500,6 +1508,7 @@ int main(int argc, char **argv) g_test_add_func("/errors/unterminated/dict_comma", unterminated_dict_comma); g_test_add_func("/errors/invalid_array_comma", invalid_array_comma); g_test_add_func("/errors/invalid_dict_comma", invalid_dict_comma); + g_test_add_func("/errors/invalid_dict_key", invalid_dict_key); g_test_add_func("/errors/unterminated/literal", unterminated_literal); g_test_add_func("/errors/limits/nesting", limits_nesting); g_test_add_func("/errors/multiple_values", multiple_values);