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libwebsockets/test-server/test-server-status.c
Andy Green a496700b3a lws_snprintf
Thanks to Fabrice Gilot for reporting the problem that led to uncovering this.

Due to a misunderstanding of the return value of snprintf (it is not truncated according
to the max size passed in) in several places relying on snprintf to truncate the length
overflows are possible.

This patch wraps snprintf with a new lws_snprintf() which does truncate its length to allow
the buffer limiting scheme to work properly.

All users should update with these fixes.
2016-09-15 02:22:57 +08:00

168 lines
4 KiB
C

/*
* libwebsockets-test-server - libwebsockets test implementation
*
* Copyright (C) 2010-2016 Andy Green <andy@warmcat.com>
*
* This file is made available under the Creative Commons CC0 1.0
* Universal Public Domain Dedication.
*
* The person who associated a work with this deed has dedicated
* the work to the public domain by waiving all of his or her rights
* to the work worldwide under copyright law, including all related
* and neighboring rights, to the extent allowed by law. You can copy,
* modify, distribute and perform the work, even for commercial purposes,
* all without asking permission.
*
* The test apps are intended to be adapted for use in your code, which
* may be proprietary. So unlike the library itself, they are licensed
* Public Domain.
*/
#include "test-server.h"
#include <time.h>
static unsigned char server_info[1024];
static int server_info_len;
static int current;
static char cache[16384];
static int cache_len;
static struct per_session_data__lws_status *list;
static int live_wsi;
static void
update_status(struct lws *wsi, struct per_session_data__lws_status *pss)
{
struct per_session_data__lws_status **pp = &list;
int subsequent = 0;
char *p = cache + LWS_PRE, *start = p;
char date[128];
time_t t;
struct tm *ptm;
#ifndef WIN32
struct tm tm;
#endif
p += lws_snprintf(p, 512, " { %s, \"wsi\":\"%d\", \"conns\":[",
server_info, live_wsi);
/* render the list */
while (*pp) {
t = (*pp)->tv_established.tv_sec;
#ifdef WIN32
ptm = localtime(&t);
if (!ptm)
#else
ptm = &tm;
if (!localtime_r(&t, &tm))
#endif
strcpy(date, "unknown");
else
#ifdef WIN32
strftime(date, sizeof(date), "%Y %H:%M %Z", ptm);
#else
strftime(date, sizeof(date), "%F %H:%M %Z", ptm);
#endif
if ((p - start) > (sizeof(cache) - 512))
break;
if (subsequent)
*p++ = ',';
subsequent = 1;
p += lws_snprintf(p, sizeof(cache) - (p - start) - 1,
"{\"peer\":\"%s\",\"time\":\"%s\","
"\"ua\":\"%s\"}",
(*pp)->ip, date, (*pp)->user_agent);
pp = &((*pp)->list);
}
p += sprintf(p, "]}");
cache_len = p - start;
lwsl_err("cache_len %d\n", cache_len);
*p = '\0';
/* since we changed the list, increment the 'version' */
current++;
/* update everyone */
lws_callback_on_writable_all_protocol(lws_get_context(wsi),
lws_get_protocol(wsi));
}
/* lws-status protocol */
int
callback_lws_status(struct lws *wsi, enum lws_callback_reasons reason,
void *user, void *in, size_t len)
{
struct per_session_data__lws_status *pss =
(struct per_session_data__lws_status *)user,
**pp;
char name[128], rip[128];
int m;
switch (reason) {
case LWS_CALLBACK_PROTOCOL_INIT:
/*
* Prepare the static server info
*/
server_info_len = sprintf((char *)server_info,
"\"version\":\"%s\","
" \"hostname\":\"%s\"",
lws_get_library_version(),
lws_canonical_hostname(
lws_get_context(wsi)));
break;
case LWS_CALLBACK_ESTABLISHED:
/*
* we keep a linked list of live pss, so we can walk it
*/
pss->last = 0;
pss->list = list;
list = pss;
live_wsi++;
lws_get_peer_addresses(wsi, lws_get_socket_fd(wsi), name,
sizeof(name), rip, sizeof(rip));
sprintf(pss->ip, "%s (%s)", name, rip);
gettimeofday(&pss->tv_established, NULL);
strcpy(pss->user_agent, "unknown");
lws_hdr_copy(wsi, pss->user_agent, sizeof(pss->user_agent),
WSI_TOKEN_HTTP_USER_AGENT);
update_status(wsi, pss);
break;
case LWS_CALLBACK_SERVER_WRITEABLE:
m = lws_write(wsi, (unsigned char *)cache + LWS_PRE, cache_len,
LWS_WRITE_TEXT);
if (m < server_info_len) {
lwsl_err("ERROR %d writing to di socket\n", m);
return -1;
}
break;
case LWS_CALLBACK_CLOSED:
/*
* remove ourselves from live pss list
*/
lwsl_err("CLOSING pss %p ********\n", pss);
pp = &list;
while (*pp) {
if (*pp == pss) {
*pp = pss->list;
pss->list = NULL;
live_wsi--;
break;
}
pp = &((*pp)->list);
}
update_status(wsi, pss);
break;
default:
break;
}
return 0;
}