From 64361379592bf80d000f3a5802dc6d3a1e9bb8d2 Mon Sep 17 00:00:00 2001 From: Sean Bright Date: Mon, 5 Feb 2018 17:46:26 -0500 Subject: AST-2018-006: Properly handle WebSocket frames with 0 length payload. In ast_websocket_read() we were not adequately checking that the payload_len was non-zero before passing it to ws_safe_read(). Calling ws_safe_read with a len argument of 0 will result in a busy loop until the underlying socket is closed. ASTERISK-27658 #close Change-Id: I9d59f83bc563f711df1a6197c57de473f6b0663a --- res/res_http_websocket.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'res') diff --git a/res/res_http_websocket.c b/res/res_http_websocket.c index bcad1c39c..19b3246b6 100644 --- a/res/res_http_websocket.c +++ b/res/res_http_websocket.c @@ -488,13 +488,20 @@ const char * AST_OPTIONAL_API_NAME(ast_websocket_session_id)(struct ast_websocke * Note during the header parsing stage we try to read in small chunks just what we need, this * is buffered data anyways, no expensive syscall required most of the time ... */ -static inline int ws_safe_read(struct ast_websocket *session, char *buf, int len, enum ast_websocket_opcode *opcode) +static inline int ws_safe_read(struct ast_websocket *session, char *buf, size_t len, enum ast_websocket_opcode *opcode) { ssize_t rlen; int xlen = len; char *rbuf = buf; int sanity = 10; + ast_assert(len > 0); + + if (!len) { + errno = EINVAL; + return -1; + } + ao2_lock(session); if (!session->stream) { ao2_unlock(session); @@ -608,9 +615,12 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha return -1; } - if (ws_safe_read(session, *payload, *payload_len, opcode)) { - return -1; + if (*payload_len) { + if (ws_safe_read(session, *payload, *payload_len, opcode)) { + return -1; + } } + /* If a mask is present unmask the payload */ if (mask_present) { unsigned int pos; -- cgit v1.2.3