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[ID 20000912.008] substr replacement of tainted data (bug)

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September 12, 2000 13:31
[ID 20000912.008] substr replacement of tainted data (bug)
Message ID:
This is a bug report for perl from,
generated with the help of perlbug 1.31 running under perl v5.6.0.

[Please enter your report here]

Consider the following program:
#! /usr/bin/perl -wT-
use strict;

local *FUN;
# The file here is not important, just a way to get tainted data
open(FUN, "/etc/group") || die "Could not open /dev/null: $!";
my $val = <FUN>;
$val =~ s/.*\n/firstlast/;
my %data;
my $ind = "a";
$data{$ind} = $val;

print "Initial string ->$data{$ind}<-\n";
print "Strip of ->", substr($data{$ind}, 0, 5, ""), "<-\n";
print "Which leaves us: ->$data{$ind}<-\n";
$data{$ind} will begin it's life as the string "firstlast",
the substr() extracts the first 5 chars, and replaces them by ""
The result should be the string "last"

That is indeed what happens without the -T option, or if $data{$ind} is
replaced by just a scalar variable.
However, in the given code, the value will remain "firstlast"

verified on linux and solaris, both in 5.6.0 and some 5.005 versions,
so it's probably an old bug.

[Please do not change anything below this line]
Site configuration information for perl v5.6.0:

Configured by ton at Wed Aug  9 23:24:07 CEST 2000.

Summary of my perl5 (revision 5.0 version 6 subversion 0) configuration:
    osname=linux, osvers=2.4.0-test5, archname=i686-linux
    uname='linux quasar 2.4.0-test5 #2 sat jul 29 04:45:14 cest 2000 i686 unknown '
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef
    useperlio=undef d_sfio=undef uselargefiles=undef 
    use64bitint=undef use64bitall=undef uselongdouble=undef usesocks=undef
    cc='cc', optimize='-O2 -fomit-frame-pointer', gccversion=egcs-2.91.66 19990314 (egcs-1.1.2 release), gccosandvers=
    cppflags='-fno-strict-aliasing -I/usr/local/include'
    ccflags ='-fno-strict-aliasing -I/usr/local/include'
    stdchar='char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=4
    alignbytes=4, usemymalloc=y, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib -L/opt/gnu/lib'
    libpth=/usr/local/lib /opt/gnu/lib /lib /usr/lib
    libs=-lnsl -lndbm -ldl -lm -lc -lposix -lcrypt -lutil
    libc=/lib/, so=so, useshrplib=true,
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic -Wl,-rpath,/usr/lib/perl5/5.6.0/i686-linux/CORE'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib -L/opt/gnu/lib'

Locally applied patches:

@INC for perl v5.6.0:

Environment for perl v5.6.0:
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PERL_BADLANG (unset)

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