Bug#11753779: MAX_CONNECT_ERRORS WORKS ONLY WHEN 1ST

              INC_HOST_ERRORS() IS CALLED.

Description: Merge from MySQL-5.1 to MySQL-5.5

sql/hostname.cc

@@ -366,6 +366,14 @@ bool ip_to_hostname(struct sockaddr_storage *ip_storage,
   err_code= vio_getnameinfo(ip, hostname_buffer, NI_MAXHOST, NULL, 0,
                             NI_NAMEREQD);
 
+  /* BEGIN : DEBUG */
+  DBUG_EXECUTE_IF("addr_fake_ipv4",
+                  {
+                    strcpy(hostname_buffer, "santa.claus.ipv4.example.com");
+                    err_code= 0;
+                  };);
+  /* END   : DEBUG */
+
   if (err_code)
   {
     // NOTE: gai_strerror() returns a string ending by a dot.
@@ -438,6 +446,12 @@ bool ip_to_hostname(struct sockaddr_storage *ip_storage,
     DBUG_RETURN(err_status);
   }
 
+  /*
+    To avoid crashing the server in DBUG_EXECUTE_IF,
+    Define a variable which depicts state of addr_info_list.
+  */
+  bool free_addr_info_list= false;
+
   /* Get IP-addresses for the resolved host name (FCrDNS technique). */
 
   struct addrinfo hints;
@@ -452,6 +466,42 @@ bool ip_to_hostname(struct sockaddr_storage *ip_storage,
                       (const char *) hostname_buffer));
 
   err_code= getaddrinfo(hostname_buffer, NULL, &hints, &addr_info_list);
+  if (err_code == 0)
+    free_addr_info_list= true;
+
+  /* BEGIN : DEBUG */
+  DBUG_EXECUTE_IF("addr_fake_ipv4",
+                  {
+                    if (free_addr_info_list)
+                      freeaddrinfo(addr_info_list);
+
+                    struct sockaddr_in *debug_addr;
+                    static struct sockaddr_in debug_sock_addr[2];
+                    static struct addrinfo debug_addr_info[2];
+                    /* Simulating ipv4 192.0.2.5 */
+                    debug_addr= & debug_sock_addr[0];
+                    debug_addr->sin_family= AF_INET;
+                    debug_addr->sin_addr.s_addr= inet_addr("192.0.2.5");
+
+                    /* Simulating ipv4 192.0.2.4 */
+                    debug_addr= & debug_sock_addr[1];
+                    debug_addr->sin_family= AF_INET;
+                    debug_addr->sin_addr.s_addr= inet_addr("192.0.2.4");
+
+                    debug_addr_info[0].ai_addr= (struct sockaddr*) & debug_sock_addr[0];
+                    debug_addr_info[0].ai_addrlen= sizeof (struct sockaddr_in);
+                    debug_addr_info[0].ai_next= & debug_addr_info[1];
+
+                    debug_addr_info[1].ai_addr= (struct sockaddr*) & debug_sock_addr[1];
+                    debug_addr_info[1].ai_addrlen= sizeof (struct sockaddr_in);
+                    debug_addr_info[1].ai_next= NULL;
+
+                    addr_info_list= & debug_addr_info[0];
+                    err_code= 0;
+                    free_addr_info_list= false;
+                  };);
+
+  /* END   : DEBUG */
 
   if (err_code == EAI_NONAME)
   {
@@ -504,7 +554,8 @@ bool ip_to_hostname(struct sockaddr_storage *ip_storage,
       {
         DBUG_PRINT("error", ("Out of memory."));
 
-        freeaddrinfo(addr_info_list);
+        if (free_addr_info_list)
+          freeaddrinfo(addr_info_list);
         DBUG_RETURN(TRUE);
       }
 
@@ -538,7 +589,8 @@ bool ip_to_hostname(struct sockaddr_storage *ip_storage,
 
   /* Free the result of getaddrinfo(). */
 
-  freeaddrinfo(addr_info_list);
+  if (free_addr_info_list)
+    freeaddrinfo(addr_info_list);
 
   /* Add an entry for the IP to the cache. */
 

sql/sql_acl.cc

@@ -8539,8 +8539,6 @@ static ulong parse_client_handshake_packet(MPVIO_EXT *mpvio,
   bool packet_has_required_size= false;
   DBUG_ASSERT(mpvio->status == MPVIO_EXT::FAILURE);
 
-  if (mpvio->connect_errors)
-    reset_host_errors(mpvio->ip);
 
   uint charset_code= 0;
   end= (char *)net->read_pos;
@@ -8551,6 +8549,11 @@ static ulong parse_client_handshake_packet(MPVIO_EXT *mpvio,
   */
   size_t bytes_remaining_in_packet= pkt_len;
   
+  DBUG_EXECUTE_IF("host_error_packet_length",
+                  {
+                    bytes_remaining_in_packet= 0;
+                  };);
+
   /*
     Peek ahead on the client capability packet and determine which version of
     the protocol should be used.
@@ -8608,6 +8611,11 @@ static ulong parse_client_handshake_packet(MPVIO_EXT *mpvio,
     */
     charset_code= default_charset_info->number;
   }
+  DBUG_EXECUTE_IF("host_error_charset",
+                  {
+                    return packet_error;
+                  };);
+
 
   DBUG_PRINT("info", ("client_character_set: %u", charset_code));
   if (mpvio->charset_adapter->init_client_charset(charset_code))
@@ -8670,6 +8678,11 @@ skip_to_ssl:
       bytes_remaining_in_packet -= AUTH_PACKET_HEADER_SIZE_PROTO_40;
     }
     
+    DBUG_EXECUTE_IF("host_error_SSL_layering",
+                    {
+                      packet_has_required_size= 0;
+                    };);
+
     if (!packet_has_required_size)
       return packet_error;
   }
@@ -8701,6 +8714,11 @@ skip_to_ssl:
 
   size_t user_len;
   char *user= get_string(&end, &bytes_remaining_in_packet, &user_len);
+  DBUG_EXECUTE_IF("host_error_user",
+                  {
+                    user= NULL;
+                  };);
+
   if (user == NULL)
     return packet_error;
 
@@ -8728,6 +8746,11 @@ skip_to_ssl:
     passwd= get_string(&end, &bytes_remaining_in_packet, &passwd_len);
   }
 
+  DBUG_EXECUTE_IF("host_error_password",
+                  {
+                    passwd= NULL;
+                  };);
+
   if (passwd == NULL)
     return packet_error;
 
@@ -9024,7 +9047,15 @@ static int server_mpvio_read_packet(MYSQL_PLUGIN_VIO *param, uchar **buf)
       goto err;
   }
   else
+  {
+    /*
+      Reset previous connection failures if any.
+    */
+    if (mpvio->connect_errors)
+      reset_host_errors(mpvio->ip);
+
     *buf= mpvio->net->read_pos;
+  }
 
   DBUG_RETURN((int)pkt_len);
 

sql/sql_connect.cc

@@ -499,6 +499,19 @@ static int check_connection(THD *thd)
       my_error(ER_BAD_HOST_ERROR, MYF(0));
       return 1;
     }
+    /* BEGIN : DEBUG */
+    DBUG_EXECUTE_IF("addr_fake_ipv4",
+                    {
+                      struct sockaddr *sa= (sockaddr *) &net->vio->remote;
+                      sa->sa_family= AF_INET;
+                      struct in_addr *ip4= &((struct sockaddr_in *)sa)->sin_addr;
+                      /* See RFC 5737, 192.0.2.0/23 is reserved */
+                      const char* fake= "192.0.2.4";
+                      ip4->s_addr= inet_addr(fake);
+                      strcpy(ip, fake);
+                    };);
+    /* END   : DEBUG */
+
     if (!(thd->main_security_ctx.ip= my_strdup(ip,MYF(MY_WME))))
       return 1; /* The error is set by my_strdup(). */
     thd->main_security_ctx.host_or_ip= thd->main_security_ctx.ip;