From df649835fe48f635a93316fdefe96ced7189316e Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Wed, 25 Nov 2015 22:23:33 +0100 Subject: qjson: Limit number of tokens in addition to total size Commit 29c75dd "json-streamer: limit the maximum recursion depth and maximum token count" attempts to guard against excessive heap usage by limiting total token size (it says "token count", but that's a lie). Total token size is a rather imprecise predictor of heap usage: many small tokens use more space than few large tokens with the same input size, because there's a constant per-token overhead: 37 bytes on my system. Tighten this up: limit the token count to 2Mi. Chosen to roughly match the 64MiB total token size limit. Signed-off-by: Markus Armbruster Reviewed-by: Eric Blake Message-Id: <1448486613-17634-13-git-send-email-armbru@redhat.com> --- qobject/json-streamer.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'qobject/json-streamer.c') diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c index e87230d..a4db4b8 100644 --- a/qobject/json-streamer.c +++ b/qobject/json-streamer.c @@ -16,6 +16,7 @@ #include "qapi/qmp/json-streamer.h" #define MAX_TOKEN_SIZE (64ULL << 20) +#define MAX_TOKEN_COUNT (2ULL << 20) #define MAX_NESTING (1ULL << 10) static void json_message_free_tokens(JSONMessageParser *parser) @@ -68,6 +69,7 @@ static void json_message_process_token(JSONLexer *lexer, GString *input, parser->bracket_count == 0)) { goto out_emit; } else if (parser->token_size > MAX_TOKEN_SIZE || + g_queue_get_length(parser->tokens) > MAX_TOKEN_COUNT || parser->bracket_count + parser->brace_count > MAX_NESTING) { /* Security consideration, we limit total memory allocated per object * and the maximum recursion depth that a message can force. -- cgit v1.1