From a7fc21783775008497b156505ace634dbbcc09b1 Mon Sep 17 00:00:00 2001
From: Kinsey Moore <kmoore@digium.com>
Date: Wed, 30 Apr 2014 13:08:07 +0000
Subject: [PATCH] Websocket: Add session locking and delay close
This resolves a race condition where data could be written to a NULL
FILE pointer causing a crash as a websocket connection was in the
process of shutting down by adding locking to websocket session writes
and by deferring session teardown until session destruction.
(closes issue ASTERISK-23605)
Review: https://reviewboard.asterisk.org/r/3481/
Reported by: Matt Jordan
........
Merged revisions 413123 from http://svn.asterisk.org/svn/asterisk/branches/11
........
Merged revisions 413124 from http://svn.asterisk.org/svn/asterisk/branches/12
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@413125 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
res/res_http_websocket.c | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/res/res_http_websocket.c b/res/res_http_websocket.c
index 47fc7568b6..d344340c75 100644
--- a/res/res_http_websocket.c
+++ b/res/res_http_websocket.c
@@ -79,6 +79,7 @@ struct ast_websocket {
size_t reconstruct; /*!< Number of bytes before a reconstructed payload will be returned and a new one started */
unsigned int secure:1; /*!< Bit to indicate that the transport is secure */
unsigned int closing:1; /*!< Bit to indicate that the session is in the process of being closed */
+ unsigned int close_sent:1; /*!< Bit to indicate that the session close opcode has been sent and no further data will be sent */
};
/*! \brief Structure definition for protocols */
@@ -164,6 +165,8 @@ static void session_destroy_fn(void *obj)
{
struct ast_websocket *session = obj;
+ ast_websocket_close(session, 0);
+
if (session->f) {
fclose(session->f);
ast_verb(2, "WebSocket connection from '%s' closed\n", ast_sockaddr_stringify(&session->address));
@@ -236,6 +239,11 @@ int AST_OPTIONAL_API_NAME(ast_websocket_server_remove_protocol)(struct ast_webso
int AST_OPTIONAL_API_NAME(ast_websocket_close)(struct ast_websocket *session, uint16_t reason)
{
char frame[4] = { 0, }; /* The header is 2 bytes and the reason code takes up another 2 bytes */
+ int res;
+
+ if (session->close_sent) {
+ return 0;
+ }
frame[0] = AST_WEBSOCKET_OPCODE_CLOSE | 0x80;
frame[1] = 2; /* The reason code is always 2 bytes */
@@ -244,8 +252,12 @@ int AST_OPTIONAL_API_NAME(ast_websocket_close)(struct ast_websocket *session, ui
put_unaligned_uint16(&frame[2], htons(reason ? reason : 1000));
session->closing = 1;
+ session->close_sent = 1;
- return (fwrite(frame, 1, 4, session->f) == 4) ? 0 : -1;
+ ao2_lock(session);
+ res = (fwrite(frame, 1, 4, session->f) == 4) ? 0 : -1;
+ ao2_unlock(session);
+ return res;
}
@@ -281,14 +293,23 @@ int AST_OPTIONAL_API_NAME(ast_websocket_write)(struct ast_websocket *session, en
put_unaligned_uint64(&frame[2], htonl(actual_length));
}
+ ao2_lock(session);
+ if (session->closing) {
+ ao2_unlock(session);
+ return -1;
+ }
+
if (fwrite(frame, 1, header_size, session->f) != header_size) {
+ ao2_unlock(session);
return -1;
}
if (fwrite(payload, 1, actual_length, session->f) != actual_length) {
+ ao2_unlock(session);
return -1;
}
fflush(session->f);
+ ao2_unlock(session);
return 0;
}
@@ -531,13 +552,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
frame_size += (*payload_len);
}
- if (!session->closing) {
- ast_websocket_close(session, 0);
- }
-
- fclose(session->f);
- session->f = NULL;
- ast_verb(2, "WebSocket connection from '%s' closed\n", ast_sockaddr_stringify(&session->address));
+ session->closing = 1;
} else {
ast_log(LOG_WARNING, "WebSocket unknown opcode %d\n", *opcode);
/* We received an opcode that we don't understand, the RFC states that 1003 is for a type of data that can't be accepted... opcodes
--
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