aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorMarkus Armbruster <armbru@redhat.com>2018-08-23 18:40:10 +0200
committerMarkus Armbruster <armbru@redhat.com>2018-08-24 20:26:37 +0200
commit2a4794ba146d6560bd77ca840ff6908f81d585f4 (patch)
tree110f5c011d9a62f67a6acda473a7c087e147e6d3
parent4d40066142278a7a9cfbde1ae481e0e94a4d24c3 (diff)
downloadqemu-2a4794ba146d6560bd77ca840ff6908f81d585f4.zip
qemu-2a4794ba146d6560bd77ca840ff6908f81d585f4.tar.gz
qemu-2a4794ba146d6560bd77ca840ff6908f81d585f4.tar.bz2
qjson: Fix qobject_from_json() & friends for multiple values
qobject_from_json() & friends use the consume_json() callback to receive either a value or an error from the parser. When they are fed a string that contains more than either one JSON value or one JSON syntax error, consume_json() gets called multiple times. When the last call receives a value, qobject_from_json() returns that value. Any other values are leaked. When any call receives an error, qobject_from_json() sets the first error received. Any other errors are thrown away. When values follow errors, qobject_from_json() returns both a value and sets an error. That's bad. Impact: * block.c's parse_json_protocol() ignores and leaks the value. It's used to to parse pseudo-filenames starting with "json:". The pseudo-filenames can come from the user or from image meta-data such as a QCOW2 image's backing file name. * vl.c's parse_display_qapi() ignores and leaks the error. It's used to parse the argument of command line option -display. * vl.c's main() case QEMU_OPTION_blockdev ignores the error and leaves it in @err. main() will then pass a pointer to a non-null Error * to net_init_clients(), which is forbidden. It can lead to assertion failure or other misbehavior. * check-qjson.c's multiple_values() demonstrates the badness. * The other callers are not affected since they only pass strings with exactly one JSON value or, in the case of negative tests, one error. The impact on the _nofail() functions is relatively harmless. They abort when any call receives an error. Else they return the last value, and leak the others, if any. Fix consume_json() as follows. On the first call, save value and error as before. On subsequent calls, if any, don't save them. If the first call saved a value, the next call, if any, replaces the value by an "Expecting at most one JSON value" error. Take care not to leak values or errors that aren't saved. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-44-armbru@redhat.com>
-rw-r--r--qobject/qjson.c15
-rw-r--r--tests/check-qjson.c10
2 files changed, 17 insertions, 8 deletions
diff --git a/qobject/qjson.c b/qobject/qjson.c
index 7395556..7f69036 100644
--- a/qobject/qjson.c
+++ b/qobject/qjson.c
@@ -33,8 +33,21 @@ static void consume_json(void *opaque, QObject *json, Error *err)
{
JSONParsingState *s = opaque;
+ assert(!json != !err);
+ assert(!s->result || !s->err);
+
+ if (s->result) {
+ qobject_unref(s->result);
+ s->result = NULL;
+ error_setg(&s->err, "Expecting at most one JSON value");
+ }
+ if (s->err) {
+ qobject_unref(json);
+ error_free(err);
+ return;
+ }
s->result = json;
- error_propagate(&s->err, err);
+ s->err = err;
}
/*
diff --git a/tests/check-qjson.c b/tests/check-qjson.c
index f344ad9..f943837 100644
--- a/tests/check-qjson.c
+++ b/tests/check-qjson.c
@@ -1443,17 +1443,13 @@ static void multiple_values(void)
Error *err = NULL;
QObject *obj;
- /* BUG this leaks the syntax tree for "false" */
obj = qobject_from_json("false true", &err);
- g_assert(qbool_get_bool(qobject_to(QBool, obj)));
- g_assert(!err);
- qobject_unref(obj);
+ error_free_or_abort(&err);
+ g_assert(obj == NULL);
- /* BUG simultaneously succeeds and fails */
obj = qobject_from_json("} true", &err);
- g_assert(qbool_get_bool(qobject_to(QBool, obj)));
error_free_or_abort(&err);
- qobject_unref(obj);
+ g_assert(obj == NULL);
}
int main(int argc, char **argv)