From 2d36e843042d2ef47f3bfc47a1a83401fdb07b84 Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Mon, 6 Aug 2018 08:53:31 +0200 Subject: [PATCH] qobject: qobject_from_jsonv() is dangerous, hide it away MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit qobject_from_jsonv() takes ownership of %p arguments. On failure, we can't generally know whether we failed before or after %p, so ownership becomes indeterminate. To avoid leaks, callers passing %p must terminate on error, e.g. by passing &error_abort. Trap for the unwary; document and give the function internal linkage. Signed-off-by: Markus Armbruster Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Eric Blake Message-Id: <20180806065344.7103-11-armbru@redhat.com> --- include/qapi/qmp/qjson.h | 2 -- qobject/qjson.c | 13 ++++++++++++- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/include/qapi/qmp/qjson.h b/include/qapi/qmp/qjson.h index dce78583dc..5ebbe5a118 100644 --- a/include/qapi/qmp/qjson.h +++ b/include/qapi/qmp/qjson.h @@ -15,8 +15,6 @@ #define QJSON_H QObject *qobject_from_json(const char *string, Error **errp); -QObject *qobject_from_jsonv(const char *string, va_list *ap, Error **errp) - GCC_FMT_ATTR(1, 0); QObject *qobject_from_vjsonf_nofail(const char *string, va_list ap) GCC_FMT_ATTR(1, 0); diff --git a/qobject/qjson.c b/qobject/qjson.c index 2e450231ff..ab4040f235 100644 --- a/qobject/qjson.c +++ b/qobject/qjson.c @@ -39,7 +39,18 @@ static void parse_json(JSONMessageParser *parser, GQueue *tokens) s->result = json_parser_parse_err(tokens, s->ap, &s->err); } -QObject *qobject_from_jsonv(const char *string, va_list *ap, Error **errp) +/* + * Parse @string as JSON value. + * If @ap is non-null, interpolate %-escapes. + * Takes ownership of %p arguments. + * On success, return the JSON value. + * On failure, store an error through @errp and return NULL. + * Ownership of %p arguments becomes indeterminate then. To avoid + * leaks, callers passing %p must terminate on error, e.g. by passing + * &error_abort. + */ +static QObject *qobject_from_jsonv(const char *string, va_list *ap, + Error **errp) { JSONParsingState state = {};