From 03c94ef761c789b56e46b7b4576a816cb97439aa Mon Sep 17 00:00:00 2001 From: Joshua Colp Date: Wed, 10 Dec 2014 13:35:52 +0000 Subject: res_http_websocket: Fix crash due to double freeing memory when receiving a payload length of zero. Frames with a payload length of 0 were incorrectly handled in res_http_websocket. Provided a frame with a payload had been received prior it was possible for a double free to occur. The realloc operation would succeed (thus freeing the payload) but be treated as an error. When the session was then torn down the payload would be freed again causing a crash. The read function now takes this into account. This change also fixes assumptions made by users of res_http_websocket. There is no guarantee that a frame received from it will be NULL terminated. ASTERISK-24472 #close Reported by: Badalian Vyacheslav Review: https://reviewboard.asterisk.org/r/4220/ Review: https://reviewboard.asterisk.org/r/4219/ ........ Merged revisions 429270 from http://svn.asterisk.org/svn/asterisk/branches/11 ........ Merged revisions 429272 from http://svn.asterisk.org/svn/asterisk/branches/12 ........ Merged revisions 429273 from http://svn.asterisk.org/svn/asterisk/branches/13 git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@429274 65c4cc65-6c06-0410-ace0-fbb531ad65f3 --- res/res_http_websocket.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) (limited to 'res/res_http_websocket.c') diff --git a/res/res_http_websocket.c b/res/res_http_websocket.c index e47bcd231..400e5eb1c 100644 --- a/res/res_http_websocket.c +++ b/res/res_http_websocket.c @@ -513,14 +513,6 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha } } - if (!(new_payload = ast_realloc(session->payload, (session->payload_len + *payload_len)))) { - ast_log(LOG_WARNING, "Failed allocation: %p, %zu, %"PRIu64"\n", - session->payload, session->payload_len, *payload_len); - *payload_len = 0; - ast_websocket_close(session, 1009); - return 0; - } - /* Per the RFC for PING we need to send back an opcode with the application data as received */ if ((*opcode == AST_WEBSOCKET_OPCODE_PING) && (ast_websocket_write(session, AST_WEBSOCKET_OPCODE_PONG, *payload, *payload_len))) { *payload_len = 0; @@ -528,9 +520,22 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha return 0; } - session->payload = new_payload; - memcpy((session->payload + session->payload_len), (*payload), (*payload_len)); - session->payload_len += *payload_len; + if (*payload_len) { + if (!(new_payload = ast_realloc(session->payload, (session->payload_len + *payload_len)))) { + ast_log(LOG_WARNING, "Failed allocation: %p, %zu, %"PRIu64"\n", + session->payload, session->payload_len, *payload_len); + *payload_len = 0; + ast_websocket_close(session, 1009); + return 0; + } + + session->payload = new_payload; + memcpy((session->payload + session->payload_len), (*payload), (*payload_len)); + session->payload_len += *payload_len; + } else if (!session->payload_len && session->payload) { + ast_free(session->payload); + session->payload = NULL; + } if (!fin && session->reconstruct && (session->payload_len < session->reconstruct)) { /* If this is not a final message we need to defer returning it until later */ -- cgit v1.2.3