From: Markus Armbruster Date: Wed, 25 Nov 2015 21:23:23 +0000 (+0100) Subject: qjson: Don't crash when input exceeds nesting limit X-Git-Tag: v2.5.0-rc2~2^2~10 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0753113a26bb8c77f951b1ea91fd4f36d099c37a;p=thirdparty%2Fqemu.git qjson: Don't crash when input exceeds nesting limit We limit nesting depth and input size to defend against input triggering excessive heap or stack memory use (commit 29c75dd json-streamer: limit the maximum recursion depth and maximum token count). However, when the nesting limit is exceeded, parser_context_peek_token()'s assertion fails. Broken in commit 65c0f1e "json-parser: don't replicate tokens at each level of recursion". To reproduce stuff 1025 open braces or brackets into QMP. Fix by taking the error exit instead of the normal one. Reported-by: Eric Blake Signed-off-by: Markus Armbruster Reviewed-by: Eric Blake Message-Id: <1448486613-17634-3-git-send-email-armbru@redhat.com> --- diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c index dced2c77a19..2bd22a738e1 100644 --- a/qobject/json-streamer.c +++ b/qobject/json-streamer.c @@ -68,13 +68,14 @@ static void json_message_process_token(JSONLexer *lexer, QString *token, JSONTok /* Security consideration, we limit total memory allocated per object * and the maximum recursion depth that a message can force. */ - goto out_emit; + goto out_emit_bad; } return; out_emit_bad: - /* clear out token list and tell the parser to emit and error + /* + * Clear out token list and tell the parser to emit an error * indication by passing it a NULL list */ QDECREF(parser->tokens);