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json-streamer: limit the maximum recursion depth and maximum token count 

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Anthony Liguori 2011-06-01 12:14:53 -05:00
parent 325601b47b
commit 29c75ddd87
1 changed files with 17 additions and 0 deletions
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17
json-streamer.c
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@ -18,6 +18,9 @@
#include "json-lexer.h"
#include "json-streamer.h"
#define MAX_TOKEN_SIZE (64ULL << 20)
#define MAX_NESTING (1ULL << 10)
static void json_message_process_token(JSONLexer *lexer, QString *token, JSONTokenType type, int x, int y)
{
JSONMessageParser *parser = container_of(lexer, JSONMessageParser, lexer);
@ -49,6 +52,8 @@ static void json_message_process_token(JSONLexer *lexer, QString *token, JSONTok
qdict_put(dict, "x", qint_from_int(x));
qdict_put(dict, "y", qint_from_int(y));
parser->token_size += token->length;
qlist_append(parser->tokens, dict);
if (parser->brace_count < 0 ||
@ -60,6 +65,17 @@ static void json_message_process_token(JSONLexer *lexer, QString *token, JSONTok
parser->emit(parser, parser->tokens);
QDECREF(parser->tokens);
parser->tokens = qlist_new();
} else if (parser->token_size > MAX_TOKEN_SIZE ||
parser->bracket_count > MAX_NESTING ||
parser->brace_count > MAX_NESTING) {
/* Security consideration, we limit total memory allocated per object
* and the maximum recursion depth that a message can force.
*/
parser->brace_count = 0;
parser->bracket_count = 0;
parser->emit(parser, parser->tokens);
QDECREF(parser->tokens);
parser->tokens = qlist_new();
}
}
@ -70,6 +86,7 @@ void json_message_parser_init(JSONMessageParser *parser,
parser->brace_count = 0;
parser->bracket_count = 0;
parser->tokens = qlist_new();
parser->token_size = 0;
json_lexer_init(&parser->lexer, json_message_process_token);
}