*** a/src/pl/plperl/GNUmakefile
--- b/src/pl/plperl/GNUmakefile
***************
*** 57,63 **** PSQLDIR = $(bindir)
  
  include $(top_srcdir)/src/Makefile.shlib
  
! plperl.o: perlchunks.h plperl_opmask.h
  
  plperl_opmask.h: plperl_opmask.pl
  	@if [ x"$(perl_privlibexp)" = x"" ]; then echo "configure switch --with-perl was not specified."; exit 1; fi
--- 57,63 ----
  
  include $(top_srcdir)/src/Makefile.shlib
  
! plperl.o: perlchunks.h plperl_opmask.h plperl_helpers.h
  
  plperl_opmask.h: plperl_opmask.pl
  	@if [ x"$(perl_privlibexp)" = x"" ]; then echo "configure switch --with-perl was not specified."; exit 1; fi
*** a/src/pl/plperl/expected/plperl.out
--- b/src/pl/plperl/expected/plperl.out
***************
*** 639,641 **** CONTEXT:  PL/Perl anonymous code block
--- 639,651 ----
  DO $do$ use warnings FATAL => qw(void) ; my @y; my $x = sort @y; 1; $do$ LANGUAGE plperl;
  ERROR:  Useless use of sort in scalar context at line 1.
  CONTEXT:  PL/Perl anonymous code block
+ --
+ -- Make sure strings are validated -- This code may fail in a non-UTF8 database
+ -- if it allows null bytes in strings.
+ --
+ CREATE OR REPLACE FUNCTION perl_zerob() RETURNS TEXT AS $$
+   return "abcd\0efg";
+ $$ LANGUAGE plperlu;
+ SELECT perl_zerob();
+ ERROR:  invalid byte sequence for encoding "UTF8": 0x00
+ CONTEXT:  PL/Perl function "perl_zerob"
*** a/src/pl/plperl/plperl_helpers.h
--- b/src/pl/plperl/plperl_helpers.h
***************
*** 7,16 ****
  static inline char *
  utf_u2e(const char *utf8_str, size_t len)
  {
! 	char	   *ret = (char *) pg_do_encoding_conversion((unsigned char *) utf8_str, len, PG_UTF8, GetDatabaseEncoding());
  
  	if (ret == utf8_str)
  		ret = pstrdup(ret);
  	return ret;
  }
  
--- 7,27 ----
  static inline char *
  utf_u2e(const char *utf8_str, size_t len)
  {
! 	int 	    enc = GetDatabaseEncoding();
! 
! 	char	   *ret = (char *) pg_do_encoding_conversion((unsigned char *) utf8_str, len, PG_UTF8, enc);
! 
! 	/*
! 	* when we are a PG_UTF8 or SQL_ASCII database
! 	* pg_do_encoding_conversion() will not do any conversion or
! 	* verification. we need to do it manually instead.
! 	*/
! 	if (enc == PG_UTF8 || enc == PG_SQL_ASCII)
! 		pg_verify_mbstr_len(PG_UTF8, utf8_str, len, false);
  
  	if (ret == utf8_str)
  		ret = pstrdup(ret);
+ 
  	return ret;
  }
  
*** a/src/pl/plperl/sql/plperl.sql
--- b/src/pl/plperl/sql/plperl.sql
***************
*** 415,417 **** DO $do$ use strict; my $name = "foo"; my $ref = $$name; $do$ LANGUAGE plperl;
--- 415,426 ----
  -- check that we can "use warnings" (in this case to turn a warn into an error)
  -- yields "ERROR:  Useless use of sort in scalar context."
  DO $do$ use warnings FATAL => qw(void) ; my @y; my $x = sort @y; 1; $do$ LANGUAGE plperl;
+ 
+ --
+ -- Make sure strings are validated -- This code may fail in a non-UTF8 database
+ -- if it allows null bytes in strings.
+ --
+ CREATE OR REPLACE FUNCTION perl_zerob() RETURNS TEXT AS $$
+   return "abcd\0efg";
+ $$ LANGUAGE plperlu;
+ SELECT perl_zerob();