curl/lib/hostasyn.c
Stefan Eissing 5a9262a333
url: dns_entry related improvements
Replace Curl_resolv_unlock() with Curl_resolv_unlink():

-replace inuse member with refcount in Curl_dns_entry

- pass Curl_dns_entry ** to unlink, so it gets always cleared

- solve potential (but unlikley) UAF in FTP's handling of looked up
  Curl_dns_entry. Esp. do not use addr information after unlinking an entry.
  In reality, the unlink will not free memory, as the dns entry is still
  referenced by the hostcache. But this is not safe and relying on no other
  code pruning the cache in the meantime.

- pass permanent flag when adding a dns entry instead of fixing timestamp
  afterwards.

url.c: fold several static *resolve_* functions into one.

Closes #14195
2024-08-03 19:51:02 +02:00

124 lines
3.8 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
#include "curl_setup.h"
/***********************************************************************
* Only for builds using asynchronous name resolves
**********************************************************************/
#ifdef CURLRES_ASYNCH
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef __VMS
#include <in.h>
#include <inet.h>
#endif
#include "urldata.h"
#include "sendf.h"
#include "hostip.h"
#include "hash.h"
#include "share.h"
#include "url.h"
#include "curl_memory.h"
/* The last #include file should be: */
#include "memdebug.h"
/*
* Curl_addrinfo_callback() gets called by ares, gethostbyname_thread()
* or getaddrinfo_thread() when we got the name resolved (or not!).
*
* If the status argument is CURL_ASYNC_SUCCESS, this function takes
* ownership of the Curl_addrinfo passed, storing the resolved data
* in the DNS cache.
*
* The storage operation locks and unlocks the DNS cache.
*/
CURLcode Curl_addrinfo_callback(struct Curl_easy *data,
int status,
struct Curl_addrinfo *ai)
{
struct Curl_dns_entry *dns = NULL;
CURLcode result = CURLE_OK;
data->state.async.status = status;
if(CURL_ASYNC_SUCCESS == status) {
if(ai) {
if(data->share)
Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
dns = Curl_cache_addr(data, ai,
data->state.async.hostname, 0,
data->state.async.port, FALSE);
if(data->share)
Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
if(!dns) {
/* failed to store, cleanup and return error */
Curl_freeaddrinfo(ai);
result = CURLE_OUT_OF_MEMORY;
}
}
else {
result = CURLE_OUT_OF_MEMORY;
}
}
data->state.async.dns = dns;
/* Set async.done TRUE last in this function since it may be used multi-
threaded and once this is TRUE the other thread may read fields from the
async struct */
data->state.async.done = TRUE;
/* IPv4: The input hostent struct will be freed by ares when we return from
this function */
return result;
}
/*
* Curl_getaddrinfo() is the generic low-level name resolve API within this
* source file. There are several versions of this function - for different
* name resolve layers (selected at build-time). They all take this same set
* of arguments
*/
struct Curl_addrinfo *Curl_getaddrinfo(struct Curl_easy *data,
const char *hostname,
int port,
int *waitp)
{
return Curl_resolver_getaddrinfo(data, hostname, port, waitp);
}
#endif /* CURLRES_ASYNCH */