MDEV-15501 : Make `proxy_protocol_networks` variable read-write.

sql/mysqld.cc

@@ -2322,7 +2322,7 @@ void clean_up(bool print_message)
   my_free(const_cast<char*>(relay_log_index));
 #endif
   free_list(opt_plugin_load_list_ptr);
-  cleanup_proxy_protocol_networks();
+  destroy_proxy_protocol_networks();
 
   /*
     The following lines may never be executed as the main thread may have
@@ -2718,7 +2718,7 @@ static void network_init(void)
   if (MYSQL_CALLBACK_ELSE(thread_scheduler, init, (), 0))
     unireg_abort(1);			/* purecov: inspected */
 
-  if (set_proxy_protocol_networks(my_proxy_protocol_networks))
+  if (init_proxy_protocol_networks(my_proxy_protocol_networks))
     unireg_abort(1);
 
   set_ports();

sql/proxy_protocol.cc

@@ -23,11 +23,14 @@
 #include <violite.h>
 #include <proxy_protocol.h>
 #include <log.h>
+#include <my_pthread.h>
 
 #define PROXY_PROTOCOL_V1_SIGNATURE "PROXY"
 #define PROXY_PROTOCOL_V2_SIGNATURE "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A"
 #define MAX_PROXY_HEADER_LEN 256
 
+static mysql_rwlock_t lock;
+
 /*
   Parse proxy protocol version 1 header (text)
 */
@@ -341,31 +344,41 @@ static int parse_subnet(char *addr_str, struct subnet *subnet)
 
   @param[in] subnets_str : networks in CIDR format,
     separated by comma and/or space
+  @param[out] out_subnets : parsed subnets;
+  @param[out] out_count : number of parsed subnets
 
   @return 0 if success, otherwise -1
 */
-int set_proxy_protocol_networks(const char *subnets_str)
+static int parse_networks(const char *subnets_str, subnet **out_subnets, size_t *out_count)
 {
+  int ret= -1;
+  subnet *subnets= 0;
+  size_t count= 0;
+  const char *p= subnets_str;
+  size_t max_subnets;
+
   if (!subnets_str || !*subnets_str)
-    return 0;
+  {
+    ret= 0;
+    goto end;
+  }
 
-  size_t max_subnets= MY_MAX(3,strlen(subnets_str)/2);
-  proxy_protocol_subnets= (subnet *)my_malloc(max_subnets * sizeof(subnet),MY_ZEROFILL);
+  max_subnets= MY_MAX(3,strlen(subnets_str)/2);
+  subnets= (subnet *)my_malloc(max_subnets * sizeof(subnet),MY_ZEROFILL);
 
   /* Check for special case '*'. */
   if (strcmp(subnets_str, "*") == 0)
   {
-
-    proxy_protocol_subnets[0].family= AF_INET;
-    proxy_protocol_subnets[1].family= AF_INET6;
-    proxy_protocol_subnets[2].family= AF_UNIX;
-    proxy_protocol_subnet_count= 3;
-    return 0;
+    subnets[0].family= AF_INET;
+    subnets[1].family= AF_INET6;
+    subnets[2].family= AF_UNIX;
+    count= 3;
+    ret= 0;
+    goto end;
   }
 
   char token[256];
-  const char *p= subnets_str;
-  for(proxy_protocol_subnet_count= 0;; proxy_protocol_subnet_count++)
+  for(count= 0;; count++)
   {
     while(*p && (*p ==',' || *p == ' '))
       p++;
@@ -377,18 +390,75 @@ int set_proxy_protocol_networks(const char *subnets_str)
       token[cnt++]= *p++;
 
     token[cnt++]=0;
-    if (cnt ==  sizeof(token))
-      return -1;
+    if (cnt == sizeof(token))
+      goto end;
 
-    if (parse_subnet(token, &proxy_protocol_subnets[proxy_protocol_subnet_count]))
+    if (parse_subnet(token, &subnets[count]))
     {
-      sql_print_error("Error parsing proxy_protocol_networks parameter, near '%s'",token);
-      return -1;
+      my_printf_error(ER_PARSE_ERROR,"Error parsing proxy_protocol_networks parameter, near '%s'",MYF(0),token);
+      goto end;
     }
   }
+
+  ret = 0;
+
+end:
+  if (ret)
+  {
+    my_free(subnets);
+    *out_subnets= NULL;
+    *out_count= 0;
+    return ret;
+  }
+  *out_subnets = subnets;
+  *out_count= count;
   return 0;
 }
 
+/**
+  Check validity of proxy_protocol_networks parameter
+  @param[in] in - input string
+  @return : true, if input is list of CIDR-style networks
+    separated by command or space
+*/
+bool proxy_protocol_networks_valid(const char *in)
+{
+  subnet *new_subnets;
+  size_t new_count;
+  int ret= parse_networks(in, &new_subnets, &new_count);
+  my_free(new_subnets);
+  return !ret;
+}
+
+
+/**
+  Set 'proxy_protocol_networks' parameter.
+
+  @param[in] spec : networks in CIDR format,
+    separated by comma and/or space
+
+  @return 0 if success, otherwise -1
+*/
+int set_proxy_protocol_networks(const char *spec)
+{
+  subnet *new_subnets;
+  subnet *old_subnet = 0;
+  size_t new_count;
+
+  int ret= parse_networks(spec, &new_subnets, &new_count);
+  if (ret)
+    return ret;
+
+  mysql_rwlock_wrlock(&lock);
+  old_subnet = proxy_protocol_subnets;
+  proxy_protocol_subnets = new_subnets;
+  proxy_protocol_subnet_count = new_count;
+  mysql_rwlock_unlock(&lock);
+  my_free(old_subnet);
+  return ret;
+}
+
+
 /**
    Compare memory areas, in memcmp().similar fashion.
    The difference to memcmp() is that size parameter is the
@@ -475,20 +545,39 @@ bool is_proxy_protocol_allowed(const sockaddr *addr)
       break;
     default:
       DBUG_ASSERT(0);
-   }
+  }
 
+  bool ret= false;
+  mysql_rwlock_rdlock(&lock);
   for (size_t i= 0; i < proxy_protocol_subnet_count; i++)
+  {
     if (addr_matches_subnet(normalized_addr, &proxy_protocol_subnets[i]))
-      return true;
+    {
+      ret= true;
+      break;
+    }
+  }
+  mysql_rwlock_unlock(&lock);
 
-  return false;
+  return ret;
 }
 
 
-void cleanup_proxy_protocol_networks()
+int init_proxy_protocol_networks(const char *spec)
 {
-  my_free(proxy_protocol_subnets);
-  proxy_protocol_subnets= 0;
-  proxy_protocol_subnet_count= 0;
+#ifdef HAVE_PSI_INTERFACE
+  static PSI_rwlock_key psi_rwlock_key;
+  static PSI_rwlock_info psi_rwlock_info={ &psi_rwlock_key, "rwlock", 0 };
+  mysql_rwlock_register("proxy_protocol", &psi_rwlock_info, 1);
+#endif
+
+  mysql_rwlock_init(psi_rwlock_key, &lock);
+  return set_proxy_protocol_networks(spec);
 }
 
+
+void destroy_proxy_protocol_networks()
+{
+  my_free(proxy_protocol_subnets);
+  mysql_rwlock_destroy(&lock);
+}

sql/proxy_protocol.h

@@ -11,5 +11,9 @@ extern bool has_proxy_protocol_header(NET *net);
 extern int parse_proxy_protocol_header(NET *net, proxy_peer_info *peer_info);
 extern bool is_proxy_protocol_allowed(const sockaddr *remote_addr);
 
+extern int init_proxy_protocol_networks(const char *spec);
+extern void destroy_proxy_protocol_networks();
+
 extern int  set_proxy_protocol_networks(const char *spec);
-extern void cleanup_proxy_protocol_networks();
+extern bool proxy_protocol_networks_valid(const char *spec);
+

sql/sys_vars.cc

@@ -4416,7 +4416,22 @@ static Sys_var_charptr Sys_license(
        READ_ONLY GLOBAL_VAR(license), NO_CMD_LINE, IN_SYSTEM_CHARSET,
        DEFAULT(STRINGIFY_ARG(LICENSE)));
 
+#include <proxy_protocol.h>
 char *my_proxy_protocol_networks;
+static bool check_proxy_protocol_networks(sys_var *, THD *, set_var *var)
+{
+  if (!var->value)
+    return false;
+  return !proxy_protocol_networks_valid(var->save_result.string_value.str);
+}
+
+
+static bool fix_proxy_protocol_networks(sys_var *, THD *, enum_var_type)
+{
+  return (bool)set_proxy_protocol_networks(my_proxy_protocol_networks);
+}
+
+
 static Sys_var_charptr Sys_proxy_protocol_networks(
     "proxy_protocol_networks", "Enable proxy protocol for these source "
     "networks. The syntax is a comma separated list of IPv4 and IPv6 "
@@ -4424,8 +4439,10 @@ static Sys_var_charptr Sys_proxy_protocol_networks(
     "a single host. \"*\" represents all networks and must the only "
     "directive on the line. String \"localhost\" represents non-TCP "
     "local connections (Unix domain socket, Windows named pipe or shared memory).",
-    READ_ONLY GLOBAL_VAR(my_proxy_protocol_networks),
-    CMD_LINE(REQUIRED_ARG), IN_FS_CHARSET, DEFAULT(""));
+    GLOBAL_VAR(my_proxy_protocol_networks), CMD_LINE(REQUIRED_ARG),
+    IN_FS_CHARSET, DEFAULT(""), NO_MUTEX_GUARD, NOT_IN_BINLOG,
+    ON_CHECK(check_proxy_protocol_networks), ON_UPDATE(fix_proxy_protocol_networks));
+
 
 static bool check_log_path(sys_var *self, THD *thd, set_var *var)
 {

tests/mysql_client_test.c

@@ -20220,6 +20220,18 @@ static void test_proxy_header_ignore()
   mysql_optionsv(m, MARIADB_OPT_PROXY_HEADER, &v2_header,16);
   DIE_UNLESS(mysql_real_connect(m, opt_host, "root", "", NULL, opt_port, opt_unix_socket, 0) == m);
   mysql_close(m);
+
+  /* test for connection denied with empty proxy_protocol_networks */
+  int rc = mysql_query(mysql, "select @@proxy_protocol_networks into @sv_proxy_protocol_networks");
+  myquery(rc);
+  mysql_query(mysql, "set global proxy_protocol_networks=default");
+  myquery(rc);
+  m = mysql_client_init(NULL);
+  mysql_optionsv(m, MARIADB_OPT_PROXY_HEADER, &v2_header,16);
+  DIE_UNLESS(mysql_real_connect(m, opt_host, "root", "", NULL, opt_port, opt_unix_socket, 0) == 0);
+  mysql_close(m);
+  mysql_query(mysql, "set global proxy_protocol_networks= @sv_proxy_protocol_networks");
+  myquery(rc);
 }