* [PATCH] json: Fix a memleak in parse_pair()
@ 2020-11-11 11:56 Alex Chen
2020-11-12 6:37 ` Markus Armbruster
0 siblings, 1 reply; 3+ messages in thread
From: Alex Chen @ 2020-11-11 11:56 UTC (permalink / raw)
To: armbru; +Cc: alex.chen, qemu-trivial, qemu-devel, zhang.zhanghailiang
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 check whether the 'QObject' returned from parse_value() is of QString type,
and if not, we free 'QObject' memory and return an error.
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 /Images/source_org/qemu_master/qemu/qobject/qnum.c:25
#3 0xaaab35584d23 in parse_literal /Images/source_org/qemu_master/qemu/qobject/json-parser.c:511
#4 0xaaab35584d23 in parse_value /Images/source_org/qemu_master/qemu/qobject/json-parser.c:554
#5 0xaaab35583d77 in parse_pair /Images/source_org/qemu_master/qemu/qobject/json-parser.c:270
#6 0xaaab355845db in parse_object /Images/source_org/qemu_master/qemu/qobject/json-parser.c:327
#7 0xaaab355845db in parse_value /Images/source_org/qemu_master/qemu/qobject/json-parser.c:546
#8 0xaaab35585b1b in json_parser_parse /Images/source_org/qemu_master/qemu/qobject/json-parser.c:580
#9 0xaaab35583703 in json_message_process_token /Images/source_org/qemu_master/qemu/qobject/json-streamer.c:92
#10 0xaaab355ddccf in json_lexer_feed_char /Images/source_org/qemu_master/qemu/qobject/json-lexer.c:313
#11 0xaaab355de0eb in json_lexer_feed /Images/source_org/qemu_master/qemu/qobject/json-lexer.c:350
#12 0xaaab354aff67 in tcp_chr_read /Images/source_org/qemu_master/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 /Images/source_org/qemu_master/qemu/iothread.c:82
#17 0xaaab3559d71b in qemu_thread_start /Images/source_org/qemu_master/qemu/util/qemu-thread-posix.c:519
Fixes: 532fb5328473 ("qapi: Make more of qobject_to()")
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Alex Chen <alex.chen@huawei.com>
Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
---
qobject/json-parser.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/qobject/json-parser.c b/qobject/json-parser.c
index d083810d37..b37762a203 100644
--- a/qobject/json-parser.c
+++ b/qobject/json-parser.c
@@ -267,10 +267,13 @@ static int parse_pair(JSONParserContext *ctxt, QDict *dict)
goto out;
}
- key = qobject_to(QString, parse_value(ctxt));
- if (!key) {
- parse_error(ctxt, peek, "key is not a string in object");
+ value = parse_value(ctxt);
+ if (!value || qobject_type(value) != QTYPE_QSTRING) {
+ qobject_unref(value);
+ parse_error(ctxt, peek, "value is not a string in object");
goto out;
+ } else {
+ key = qobject_to(QString, value);
}
token = parser_context_pop_token(ctxt);
--
2.19.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] json: Fix a memleak in parse_pair()
2020-11-11 11:56 [PATCH] json: Fix a memleak in parse_pair() Alex Chen
@ 2020-11-12 6:37 ` Markus Armbruster
2020-11-13 14:51 ` Alex Chen
0 siblings, 1 reply; 3+ messages in thread
From: Markus Armbruster @ 2020-11-12 6:37 UTC (permalink / raw)
To: Alex Chen; +Cc: qemu-trivial, qemu-devel, zhang.zhanghailiang
Alex Chen <alex.chen@huawei.com> writes:
> 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 check whether the 'QObject' returned from parse_value() is of QString type,
> and if not, we free 'QObject' memory and return an error.
>
> 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 /Images/source_org/qemu_master/qemu/qobject/qnum.c:25
> #3 0xaaab35584d23 in parse_literal /Images/source_org/qemu_master/qemu/qobject/json-parser.c:511
> #4 0xaaab35584d23 in parse_value /Images/source_org/qemu_master/qemu/qobject/json-parser.c:554
> #5 0xaaab35583d77 in parse_pair /Images/source_org/qemu_master/qemu/qobject/json-parser.c:270
> #6 0xaaab355845db in parse_object /Images/source_org/qemu_master/qemu/qobject/json-parser.c:327
> #7 0xaaab355845db in parse_value /Images/source_org/qemu_master/qemu/qobject/json-parser.c:546
> #8 0xaaab35585b1b in json_parser_parse /Images/source_org/qemu_master/qemu/qobject/json-parser.c:580
> #9 0xaaab35583703 in json_message_process_token /Images/source_org/qemu_master/qemu/qobject/json-streamer.c:92
> #10 0xaaab355ddccf in json_lexer_feed_char /Images/source_org/qemu_master/qemu/qobject/json-lexer.c:313
> #11 0xaaab355de0eb in json_lexer_feed /Images/source_org/qemu_master/qemu/qobject/json-lexer.c:350
> #12 0xaaab354aff67 in tcp_chr_read /Images/source_org/qemu_master/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 /Images/source_org/qemu_master/qemu/iothread.c:82
> #17 0xaaab3559d71b in qemu_thread_start /Images/source_org/qemu_master/qemu/util/qemu-thread-posix.c:519
Good catch, thanks!
> Fixes: 532fb5328473 ("qapi: Make more of qobject_to()")
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Alex Chen <alex.chen@huawei.com>
> Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
> ---
> qobject/json-parser.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/qobject/json-parser.c b/qobject/json-parser.c
> index d083810d37..b37762a203 100644
> --- a/qobject/json-parser.c
> +++ b/qobject/json-parser.c
> @@ -267,10 +267,13 @@ static int parse_pair(JSONParserContext *ctxt, QDict *dict)
> goto out;
> }
>
> - key = qobject_to(QString, parse_value(ctxt));
> - if (!key) {
> - parse_error(ctxt, peek, "key is not a string in object");
> + value = parse_value(ctxt);
> + if (!value || qobject_type(value) != QTYPE_QSTRING) {
The "is string" test becomes more cumbersome. Also, we reuse @value for
another purpose.
> + qobject_unref(value);
> + parse_error(ctxt, peek, "value is not a string in object");
Changing error messages in a memory leak fix is inappropriate.
Accident?
> goto out;
> + } else {
> + key = qobject_to(QString, value);
> }
>
> token = parser_context_pop_token(ctxt);
Here's a simpler, straightforward fix, with a test case thrown in:
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);
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] json: Fix a memleak in parse_pair()
2020-11-12 6:37 ` Markus Armbruster
@ 2020-11-13 14:51 ` Alex Chen
0 siblings, 0 replies; 3+ messages in thread
From: Alex Chen @ 2020-11-13 14:51 UTC (permalink / raw)
To: Markus Armbruster; +Cc: qemu-trivial, qemu-devel, zhang.zhanghailiang
On 2020/11/12 14:37, Markus Armbruster wrote:
> Alex Chen <alex.chen@huawei.com> writes:
>
>> 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 check whether the 'QObject' returned from parse_value() is of QString type,
>> and if not, we free 'QObject' memory and return an error.
>>
>> 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 /Images/source_org/qemu_master/qemu/qobject/qnum.c:25
>> #3 0xaaab35584d23 in parse_literal /Images/source_org/qemu_master/qemu/qobject/json-parser.c:511
>> #4 0xaaab35584d23 in parse_value /Images/source_org/qemu_master/qemu/qobject/json-parser.c:554
>> #5 0xaaab35583d77 in parse_pair /Images/source_org/qemu_master/qemu/qobject/json-parser.c:270
>> #6 0xaaab355845db in parse_object /Images/source_org/qemu_master/qemu/qobject/json-parser.c:327
>> #7 0xaaab355845db in parse_value /Images/source_org/qemu_master/qemu/qobject/json-parser.c:546
>> #8 0xaaab35585b1b in json_parser_parse /Images/source_org/qemu_master/qemu/qobject/json-parser.c:580
>> #9 0xaaab35583703 in json_message_process_token /Images/source_org/qemu_master/qemu/qobject/json-streamer.c:92
>> #10 0xaaab355ddccf in json_lexer_feed_char /Images/source_org/qemu_master/qemu/qobject/json-lexer.c:313
>> #11 0xaaab355de0eb in json_lexer_feed /Images/source_org/qemu_master/qemu/qobject/json-lexer.c:350
>> #12 0xaaab354aff67 in tcp_chr_read /Images/source_org/qemu_master/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 /Images/source_org/qemu_master/qemu/iothread.c:82
>> #17 0xaaab3559d71b in qemu_thread_start /Images/source_org/qemu_master/qemu/util/qemu-thread-posix.c:519
>
> Good catch, thanks!
>
>> Fixes: 532fb5328473 ("qapi: Make more of qobject_to()")
>> Reported-by: Euler Robot <euler.robot@huawei.com>
>> Signed-off-by: Alex Chen <alex.chen@huawei.com>
>> Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
>> ---
>> qobject/json-parser.c | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/qobject/json-parser.c b/qobject/json-parser.c
>> index d083810d37..b37762a203 100644
>> --- a/qobject/json-parser.c
>> +++ b/qobject/json-parser.c
>> @@ -267,10 +267,13 @@ static int parse_pair(JSONParserContext *ctxt, QDict *dict)
>> goto out;
>> }
>>
>> - key = qobject_to(QString, parse_value(ctxt));
>> - if (!key) {
>> - parse_error(ctxt, peek, "key is not a string in object");
>> + value = parse_value(ctxt);
>> + if (!value || qobject_type(value) != QTYPE_QSTRING) {
>
> The "is string" test becomes more cumbersome. Also, we reuse @value for
> another purpose.
>
>> + qobject_unref(value);
>> + parse_error(ctxt, peek, "value is not a string in object");
>
> Changing error messages in a memory leak fix is inappropriate.
> Accident?
>
>> goto out;
>> + } else {
>> + key = qobject_to(QString, value);
>> }
>>
>> token = parser_context_pop_token(ctxt);
>
> Here's a simpler, straightforward fix, with a test case thrown in:
>
> 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);
>
Thanks for your review，your patch is better than mine.
I will send the patch v2.
Thanks,
Alex
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-11-13 14:53 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2020-11-11 11:56 [PATCH] json: Fix a memleak in parse_pair() Alex Chen
2020-11-12 6:37 ` Markus Armbruster
2020-11-13 14:51 ` Alex Chen
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