Commit 2caa454d authored by Daniel Stenberg's avatar Daniel Stenberg
Browse files

resolve: don't leak pre-populated dns entries 

CURLOPT_RESOLVE populates the DNS cache with entries that are marked as
eternally in use. Those entries need to be taken care of when the cache
is killed off.

Bug: http://curl.haxx.se/bug/view.cgi?id=3463121
Reported by: "tw84452852"
parent 3e4181f8

lib/hostip.c

+21 −0
Original line number Diff line number Diff line
@@ -721,4 +721,25 @@ struct curl_hash *Curl_mk_dnscache(void) 
  return Curl_hash_alloc(7, Curl_hash_str, Curl_str_key_compare, freednsentry);

}



static int hostcache_inuse(void *data, void *hc)

{

  struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc;



  if(c->inuse == 1)

    Curl_resolv_unlock(data, c);



  return 1; /* free all entries */

}



void Curl_hostcache_destroy(struct SessionHandle *data)

{

  /* Entries added to the hostcache with the CURLOPT_RESOLVE function are

   * still present in the cache with the inuse counter set to 1. Detect them

   * and cleanup!

   */

  Curl_hash_clean_with_criterium(data->dns.hostcache, data, hostcache_inuse);



  Curl_hash_destroy(data->dns.hostcache);

  data->dns.hostcachetype = HCACHE_NONE;

  data->dns.hostcache = NULL;

}

lib/hostip.h

+5 −0
Original line number Diff line number Diff line
@@ -200,4 +200,9 @@ extern sigjmp_buf curl_jmpenv; 
 */

CURLcode Curl_set_dns_servers(struct SessionHandle *data, char *servers);



/*

 * Destroy the hostcache of this handle.

 */

void Curl_hostcache_destroy(struct SessionHandle *data);



#endif /* HEADER_CURL_HOSTIP_H */

lib/url.c

+3 −12
Original line number Diff line number Diff line
@@ -467,11 +467,8 @@ CURLcode Curl_close(struct SessionHandle *data) 
    return CURLE_OK;

  }



  if(data->dns.hostcachetype == HCACHE_PRIVATE) {

    Curl_hash_destroy(data->dns.hostcache);

    data->dns.hostcachetype = HCACHE_NONE;

    data->dns.hostcache = NULL;

  }

  if(data->dns.hostcachetype == HCACHE_PRIVATE)

    Curl_hostcache_destroy(data);



  if(data->state.rangestringalloc)

    free(data->state.range);
@@ -2131,7 +2128,7 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option, 
      if(data->share->hostcache) {

        /* use shared host cache, first free the private one if any */

        if(data->dns.hostcachetype == HCACHE_PRIVATE)

          Curl_hash_destroy(data->dns.hostcache);

          Curl_hostcache_destroy(data);



        data->dns.hostcache = data->share->hostcache;

        data->dns.hostcachetype = HCACHE_SHARED;
@@ -2626,12 +2623,6 @@ CURLcode Curl_disconnect(struct connectdata *conn, bool dead_connection) 
    conn->dns_entry = NULL;

  }



#if defined(DEBUGBUILD) && defined(AGGRESIVE_TEST)

  /* scan for DNS cache entries still marked as in use */

  Curl_hash_apply(data->hostcache,

                  NULL, Curl_scan_cache_used);

#endif



  Curl_hostcache_prune(data); /* kill old DNS cache entries */



  {