From ba9229d280e035872ac2258873c1b9f34cc8c4a9 Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Wed, 27 Jul 2016 07:35:01 +0200 Subject: [PATCH 03/16] qjson: Don't crash when input exceeds nesting limit RH-Author: Markus Armbruster Message-id: <1469604913-12442-5-git-send-email-armbru@redhat.com> Patchwork-id: 71472 O-Subject: [RHEL-7.3 qemu-kvm PATCH v2 03/15] qjson: Don't crash when input exceeds nesting limit Bugzilla: 1276036 RH-Acked-by: Miroslav Rezanina RH-Acked-by: John Snow RH-Acked-by: Paolo Bonzini 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> (cherry picked from commit 0753113a26bb8c77f951b1ea91fd4f36d099c37a) Signed-off-by: Markus Armbruster Signed-off-by: Miroslav Rezanina --- qobject/json-streamer.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c index dced2c7..2bd22a7 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); -- 1.8.3.1