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curl/lib/asyn-ares.c
Daniel Stenberg ac9a179fe9
multi: fix memory leak when stopped during name resolve
When the application just started the transfer and then stops it while
the name resolve in the background thread hasn't completed, we need to
wait for the resolve to complete and then cleanup data accordingly.

Enabled test 1553 again and added test 1590 to also check when the host
name resolves successfully.

Detected by OSS-fuzz.
Closes #1968
2018-06-16 12:01:27 +02:00

702 lines
20 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2018, 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.haxx.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.
*
***************************************************************************/
#include "curl_setup.h"
/***********************************************************************
* Only for ares-enabled builds
* And only for functions that fulfill the asynch resolver backend API
* as defined in asyn.h, nothing else belongs in this file!
**********************************************************************/
#ifdef CURLRES_ARES
#include <limits.h>
#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
#ifdef HAVE_PROCESS_H
#include <process.h>
#endif
#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
#undef in_addr_t
#define in_addr_t unsigned long
#endif
#include "urldata.h"
#include "sendf.h"
#include "hostip.h"
#include "hash.h"
#include "share.h"
#include "strerror.h"
#include "url.h"
#include "multiif.h"
#include "inet_pton.h"
#include "connect.h"
#include "select.h"
#include "progress.h"
# if defined(CURL_STATICLIB) && !defined(CARES_STATICLIB) && \
(defined(WIN32) || defined(_WIN32) || defined(__SYMBIAN32__))
# define CARES_STATICLIB
# endif
# include <ares.h>
# include <ares_version.h> /* really old c-ares didn't include this by
itself */
#if ARES_VERSION >= 0x010500
/* c-ares 1.5.0 or later, the callback proto is modified */
#define HAVE_CARES_CALLBACK_TIMEOUTS 1
#endif
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"
struct ResolverResults {
int num_pending; /* number of ares_gethostbyname() requests */
Curl_addrinfo *temp_ai; /* intermediary result while fetching c-ares parts */
int last_status;
};
/*
* Curl_resolver_global_init() - the generic low-level asynchronous name
* resolve API. Called from curl_global_init() to initialize global resolver
* environment. Initializes ares library.
*/
int Curl_resolver_global_init(void)
{
#ifdef CARES_HAVE_ARES_LIBRARY_INIT
if(ares_library_init(ARES_LIB_INIT_ALL)) {
return CURLE_FAILED_INIT;
}
#endif
return CURLE_OK;
}
/*
* Curl_resolver_global_cleanup()
*
* Called from curl_global_cleanup() to destroy global resolver environment.
* Deinitializes ares library.
*/
void Curl_resolver_global_cleanup(void)
{
#ifdef CARES_HAVE_ARES_LIBRARY_CLEANUP
ares_library_cleanup();
#endif
}
/*
* Curl_resolver_init()
*
* Called from curl_easy_init() -> Curl_open() to initialize resolver
* URL-state specific environment ('resolver' member of the UrlState
* structure). Fills the passed pointer by the initialized ares_channel.
*/
CURLcode Curl_resolver_init(void **resolver)
{
int status = ares_init((ares_channel*)resolver);
if(status != ARES_SUCCESS) {
if(status == ARES_ENOMEM)
return CURLE_OUT_OF_MEMORY;
else
return CURLE_FAILED_INIT;
}
return CURLE_OK;
/* make sure that all other returns from this function should destroy the
ares channel before returning error! */
}
/*
* Curl_resolver_cleanup()
*
* Called from curl_easy_cleanup() -> Curl_close() to cleanup resolver
* URL-state specific environment ('resolver' member of the UrlState
* structure). Destroys the ares channel.
*/
void Curl_resolver_cleanup(void *resolver)
{
ares_destroy((ares_channel)resolver);
}
/*
* Curl_resolver_duphandle()
*
* Called from curl_easy_duphandle() to duplicate resolver URL-state specific
* environment ('resolver' member of the UrlState structure). Duplicates the
* 'from' ares channel and passes the resulting channel to the 'to' pointer.
*/
int Curl_resolver_duphandle(void **to, void *from)
{
/* Clone the ares channel for the new handle */
if(ARES_SUCCESS != ares_dup((ares_channel*)to, (ares_channel)from))
return CURLE_FAILED_INIT;
return CURLE_OK;
}
static void destroy_async_data(struct Curl_async *async);
/*
* Cancel all possibly still on-going resolves for this connection.
*/
void Curl_resolver_cancel(struct connectdata *conn)
{
if(conn->data && conn->data->state.resolver)
ares_cancel((ares_channel)conn->data->state.resolver);
destroy_async_data(&conn->async);
}
/*
* destroy_async_data() cleans up async resolver data.
*/
static void destroy_async_data(struct Curl_async *async)
{
free(async->hostname);
if(async->os_specific) {
struct ResolverResults *res = (struct ResolverResults *)async->os_specific;
if(res) {
if(res->temp_ai) {
Curl_freeaddrinfo(res->temp_ai);
res->temp_ai = NULL;
}
free(res);
}
async->os_specific = NULL;
}
async->hostname = NULL;
}
/*
* Curl_resolver_getsock() is called when someone from the outside world
* (using curl_multi_fdset()) wants to get our fd_set setup and we're talking
* with ares. The caller must make sure that this function is only called when
* we have a working ares channel.
*
* Returns: sockets-in-use-bitmap
*/
int Curl_resolver_getsock(struct connectdata *conn,
curl_socket_t *socks,
int numsocks)
{
struct timeval maxtime;
struct timeval timebuf;
struct timeval *timeout;
long milli;
int max = ares_getsock((ares_channel)conn->data->state.resolver,
(ares_socket_t *)socks, numsocks);
maxtime.tv_sec = CURL_TIMEOUT_RESOLVE;
maxtime.tv_usec = 0;
timeout = ares_timeout((ares_channel)conn->data->state.resolver, &maxtime,
&timebuf);
milli = (timeout->tv_sec * 1000) + (timeout->tv_usec/1000);
if(milli == 0)
milli += 10;
Curl_expire(conn->data, milli, EXPIRE_ASYNC_NAME);
return max;
}
/*
* waitperform()
*
* 1) Ask ares what sockets it currently plays with, then
* 2) wait for the timeout period to check for action on ares' sockets.
* 3) tell ares to act on all the sockets marked as "with action"
*
* return number of sockets it worked on
*/
static int waitperform(struct connectdata *conn, int timeout_ms)
{
struct Curl_easy *data = conn->data;
int nfds;
int bitmask;
ares_socket_t socks[ARES_GETSOCK_MAXNUM];
struct pollfd pfd[ARES_GETSOCK_MAXNUM];
int i;
int num = 0;
bitmask = ares_getsock((ares_channel)data->state.resolver, socks,
ARES_GETSOCK_MAXNUM);
for(i = 0; i < ARES_GETSOCK_MAXNUM; i++) {
pfd[i].events = 0;
pfd[i].revents = 0;
if(ARES_GETSOCK_READABLE(bitmask, i)) {
pfd[i].fd = socks[i];
pfd[i].events |= POLLRDNORM|POLLIN;
}
if(ARES_GETSOCK_WRITABLE(bitmask, i)) {
pfd[i].fd = socks[i];
pfd[i].events |= POLLWRNORM|POLLOUT;
}
if(pfd[i].events != 0)
num++;
else
break;
}
if(num)
nfds = Curl_poll(pfd, num, timeout_ms);
else
nfds = 0;
if(!nfds)
/* Call ares_process() unconditonally here, even if we simply timed out
above, as otherwise the ares name resolve won't timeout! */
ares_process_fd((ares_channel)data->state.resolver, ARES_SOCKET_BAD,
ARES_SOCKET_BAD);
else {
/* move through the descriptors and ask for processing on them */
for(i = 0; i < num; i++)
ares_process_fd((ares_channel)data->state.resolver,
pfd[i].revents & (POLLRDNORM|POLLIN)?
pfd[i].fd:ARES_SOCKET_BAD,
pfd[i].revents & (POLLWRNORM|POLLOUT)?
pfd[i].fd:ARES_SOCKET_BAD);
}
return nfds;
}
/*
* Curl_resolver_is_resolved() is called repeatedly to check if a previous
* name resolve request has completed. It should also make sure to time-out if
* the operation seems to take too long.
*
* Returns normal CURLcode errors.
*/
CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
struct Curl_dns_entry **dns)
{
struct Curl_easy *data = conn->data;
struct ResolverResults *res = (struct ResolverResults *)
conn->async.os_specific;
CURLcode result = CURLE_OK;
if(dns)
*dns = NULL;
waitperform(conn, 0);
if(res && !res->num_pending) {
if(dns) {
(void)Curl_addrinfo_callback(conn, res->last_status, res->temp_ai);
/* temp_ai ownership is moved to the connection, so we need not free-up
them */
res->temp_ai = NULL;
}
if(!conn->async.dns) {
failf(data, "Could not resolve: %s (%s)",
conn->async.hostname, ares_strerror(conn->async.status));
result = conn->bits.proxy?CURLE_COULDNT_RESOLVE_PROXY:
CURLE_COULDNT_RESOLVE_HOST;
}
else if(dns)
*dns = conn->async.dns;
destroy_async_data(&conn->async);
}
return result;
}
/*
* Curl_resolver_wait_resolv()
*
* waits for a resolve to finish. This function should be avoided since using
* this risk getting the multi interface to "hang".
*
* If 'entry' is non-NULL, make it point to the resolved dns entry
*
* Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved, and
* CURLE_OPERATION_TIMEDOUT if a time-out occurred.
*/
CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
struct Curl_dns_entry **entry)
{
CURLcode result = CURLE_OK;
struct Curl_easy *data = conn->data;
timediff_t timeout;
struct curltime now = Curl_now();
struct Curl_dns_entry *temp_entry;
if(entry)
*entry = NULL; /* clear on entry */
timeout = Curl_timeleft(data, &now, TRUE);
if(timeout < 0) {
/* already expired! */
connclose(conn, "Timed out before name resolve started");
return CURLE_OPERATION_TIMEDOUT;
}
if(!timeout)
timeout = CURL_TIMEOUT_RESOLVE * 1000; /* default name resolve timeout */
/* Wait for the name resolve query to complete. */
while(!result) {
struct timeval *tvp, tv, store;
int itimeout;
int timeout_ms;
itimeout = (timeout > (long)INT_MAX) ? INT_MAX : (int)timeout;
store.tv_sec = itimeout/1000;
store.tv_usec = (itimeout%1000)*1000;
tvp = ares_timeout((ares_channel)data->state.resolver, &store, &tv);
/* use the timeout period ares returned to us above if less than one
second is left, otherwise just use 1000ms to make sure the progress
callback gets called frequent enough */
if(!tvp->tv_sec)
timeout_ms = (int)(tvp->tv_usec/1000);
else
timeout_ms = 1000;
waitperform(conn, timeout_ms);
result = Curl_resolver_is_resolved(conn, entry?&temp_entry:NULL);
if(result || conn->async.done)
break;
if(Curl_pgrsUpdate(conn))
result = CURLE_ABORTED_BY_CALLBACK;
else {
struct curltime now2 = Curl_now();
timediff_t timediff = Curl_timediff(now2, now); /* spent time */
if(timediff <= 0)
timeout -= 1; /* always deduct at least 1 */
else if(timediff > timeout)
timeout = -1;
else
timeout -= (long)timediff;
now = now2; /* for next loop */
}
if(timeout < 0)
result = CURLE_OPERATION_TIMEDOUT;
}
if(result)
/* failure, so we cancel the ares operation */
ares_cancel((ares_channel)data->state.resolver);
/* Operation complete, if the lookup was successful we now have the entry
in the cache. */
if(entry)
*entry = conn->async.dns;
if(result)
/* close the connection, since we can't return failure here without
cleaning up this connection properly.
TODO: remove this action from here, it is not a name resolver decision.
*/
connclose(conn, "c-ares resolve failed");
return result;
}
/* Connects results to the list */
static void compound_results(struct ResolverResults *res,
Curl_addrinfo *ai)
{
Curl_addrinfo *ai_tail;
if(!ai)
return;
ai_tail = ai;
while(ai_tail->ai_next)
ai_tail = ai_tail->ai_next;
/* Add the new results to the list of old results. */
ai_tail->ai_next = res->temp_ai;
res->temp_ai = ai;
}
/*
* ares_query_completed_cb() is the callback that ares will call when
* the host query initiated by ares_gethostbyname() from Curl_getaddrinfo(),
* when using ares, is completed either successfully or with failure.
*/
static void query_completed_cb(void *arg, /* (struct connectdata *) */
int status,
#ifdef HAVE_CARES_CALLBACK_TIMEOUTS
int timeouts,
#endif
struct hostent *hostent)
{
struct connectdata *conn = (struct connectdata *)arg;
struct ResolverResults *res;
#ifdef HAVE_CARES_CALLBACK_TIMEOUTS
(void)timeouts; /* ignored */
#endif
if(ARES_EDESTRUCTION == status)
/* when this ares handle is getting destroyed, the 'arg' pointer may not
be valid so only defer it when we know the 'status' says its fine! */
return;
res = (struct ResolverResults *)conn->async.os_specific;
res->num_pending--;
if(CURL_ASYNC_SUCCESS == status) {
Curl_addrinfo *ai = Curl_he2ai(hostent, conn->async.port);
if(ai) {
compound_results(res, ai);
}
}
/* A successful result overwrites any previous error */
if(res->last_status != ARES_SUCCESS)
res->last_status = status;
}
/*
* Curl_resolver_getaddrinfo() - when using ares
*
* Returns name information about the given hostname and port number. If
* successful, the 'hostent' is returned and the forth argument will point to
* memory we need to free after use. That memory *MUST* be freed with
* Curl_freeaddrinfo(), nothing else.
*/
Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
const char *hostname,
int port,
int *waitp)
{
char *bufp;
struct Curl_easy *data = conn->data;
struct in_addr in;
int family = PF_INET;
#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
struct in6_addr in6;
#endif /* CURLRES_IPV6 */
*waitp = 0; /* default to synchronous response */
/* First check if this is an IPv4 address string */
if(Curl_inet_pton(AF_INET, hostname, &in) > 0) {
/* This is a dotted IP address 123.123.123.123-style */
return Curl_ip2addr(AF_INET, &in, hostname, port);
}
#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
/* Otherwise, check if this is an IPv6 address string */
if(Curl_inet_pton (AF_INET6, hostname, &in6) > 0)
/* This must be an IPv6 address literal. */
return Curl_ip2addr(AF_INET6, &in6, hostname, port);
switch(conn->ip_version) {
default:
#if ARES_VERSION >= 0x010601
family = PF_UNSPEC; /* supported by c-ares since 1.6.1, so for older
c-ares versions this just falls through and defaults
to PF_INET */
break;
#endif
case CURL_IPRESOLVE_V4:
family = PF_INET;
break;
case CURL_IPRESOLVE_V6:
family = PF_INET6;
break;
}
#endif /* CURLRES_IPV6 */
bufp = strdup(hostname);
if(bufp) {
struct ResolverResults *res = NULL;
free(conn->async.hostname);
conn->async.hostname = bufp;
conn->async.port = port;
conn->async.done = FALSE; /* not done */
conn->async.status = 0; /* clear */
conn->async.dns = NULL; /* clear */
res = calloc(sizeof(struct ResolverResults), 1);
if(!res) {
free(conn->async.hostname);
conn->async.hostname = NULL;
return NULL;
}
conn->async.os_specific = res;
/* initial status - failed */
res->last_status = ARES_ENOTFOUND;
#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
if(family == PF_UNSPEC) {
if(Curl_ipv6works()) {
res->num_pending = 2;
/* areschannel is already setup in the Curl_open() function */
ares_gethostbyname((ares_channel)data->state.resolver, hostname,
PF_INET, query_completed_cb, conn);
ares_gethostbyname((ares_channel)data->state.resolver, hostname,
PF_INET6, query_completed_cb, conn);
}
else {
res->num_pending = 1;
/* areschannel is already setup in the Curl_open() function */
ares_gethostbyname((ares_channel)data->state.resolver, hostname,
PF_INET, query_completed_cb, conn);
}
}
else
#endif /* CURLRES_IPV6 */
{
res->num_pending = 1;
/* areschannel is already setup in the Curl_open() function */
ares_gethostbyname((ares_channel)data->state.resolver, hostname, family,
query_completed_cb, conn);
}
*waitp = 1; /* expect asynchronous response */
}
return NULL; /* no struct yet */
}
CURLcode Curl_set_dns_servers(struct Curl_easy *data,
char *servers)
{
CURLcode result = CURLE_NOT_BUILT_IN;
int ares_result;
/* If server is NULL or empty, this would purge all DNS servers
* from ares library, which will cause any and all queries to fail.
* So, just return OK if none are configured and don't actually make
* any changes to c-ares. This lets c-ares use it's defaults, which
* it gets from the OS (for instance from /etc/resolv.conf on Linux).
*/
if(!(servers && servers[0]))
return CURLE_OK;
#if (ARES_VERSION >= 0x010704)
ares_result = ares_set_servers_csv(data->state.resolver, servers);
switch(ares_result) {
case ARES_SUCCESS:
result = CURLE_OK;
break;
case ARES_ENOMEM:
result = CURLE_OUT_OF_MEMORY;
break;
case ARES_ENOTINITIALIZED:
case ARES_ENODATA:
case ARES_EBADSTR:
default:
result = CURLE_BAD_FUNCTION_ARGUMENT;
break;
}
#else /* too old c-ares version! */
(void)data;
(void)(ares_result);
#endif
return result;
}
CURLcode Curl_set_dns_interface(struct Curl_easy *data,
const char *interf)
{
#if (ARES_VERSION >= 0x010704)
if(!interf)
interf = "";
ares_set_local_dev((ares_channel)data->state.resolver, interf);
return CURLE_OK;
#else /* c-ares version too old! */
(void)data;
(void)interf;
return CURLE_NOT_BUILT_IN;
#endif
}
CURLcode Curl_set_dns_local_ip4(struct Curl_easy *data,
const char *local_ip4)
{
#if (ARES_VERSION >= 0x010704)
struct in_addr a4;
if((!local_ip4) || (local_ip4[0] == 0)) {
a4.s_addr = 0; /* disabled: do not bind to a specific address */
}
else {
if(Curl_inet_pton(AF_INET, local_ip4, &a4) != 1) {
return CURLE_BAD_FUNCTION_ARGUMENT;
}
}
ares_set_local_ip4((ares_channel)data->state.resolver, ntohl(a4.s_addr));
return CURLE_OK;
#else /* c-ares version too old! */
(void)data;
(void)local_ip4;
return CURLE_NOT_BUILT_IN;
#endif
}
CURLcode Curl_set_dns_local_ip6(struct Curl_easy *data,
const char *local_ip6)
{
#if (ARES_VERSION >= 0x010704) && defined(ENABLE_IPV6)
unsigned char a6[INET6_ADDRSTRLEN];
if((!local_ip6) || (local_ip6[0] == 0)) {
/* disabled: do not bind to a specific address */
memset(a6, 0, sizeof(a6));
}
else {
if(Curl_inet_pton(AF_INET6, local_ip6, a6) != 1) {
return CURLE_BAD_FUNCTION_ARGUMENT;
}
}
ares_set_local_ip6((ares_channel)data->state.resolver, a6);
return CURLE_OK;
#else /* c-ares version too old! */
(void)data;
(void)local_ip6;
return CURLE_NOT_BUILT_IN;
#endif
}
#endif /* CURLRES_ARES */