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cut: better input validation for -b and -f #403

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merged 1 commit into from
Jan 9, 2024
Merged

cut: better input validation for -b and -f #403

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82 changes: 48 additions & 34 deletions bin/cut
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,6 @@ License: perl
# Perl Power Tools -- http://language.perl.com/ppt/
#

$^W = 1; # -w
use strict;

use File::Basename qw(basename);
Expand Down Expand Up @@ -50,6 +49,18 @@ EOT
exit EX_FAILURE;
}

sub checknum {
my $n = shift;
if ($n !~ m/\A\-?[0-9]+\Z/) {
warn "$me: unexpected byte or field number: '$n'\n";
exit EX_FAILURE;
}
if ($n == 0) {
warn "$me: bytes and fields are numbered from 1\n";
exit EX_FAILURE;
}
}

my %opt;
getopts('b:c:d:f:ns', \%opt) or usage();

Expand All @@ -61,35 +72,36 @@ $opt{b} = $opt{c} if defined $opt{c};
if (defined ($opt{b})) {

my @list = split (/,/, $opt{b});
foreach my $item (@list) {
if ($item == 0) {
warn "$me: byte positions are numbered from 1\n";
exit EX_FAILURE;
}
}

while (<>) {
chomp;

foreach my $item (@list) {
my ($start,$end) = split (/-/, $item);
if ($start and $end and $start > $end) {
warn "$me: invalid byte list\n";
exit EX_FAILURE;
my ($start, $end);
if (substr($item, 0, 1) eq '-') {
checknum($item);
$start = 1;
$end = abs($item) + 1;
} elsif (index($item, '-') == -1) {
checknum($item);
$start = $item;
$end = $start + 1;
} else {
($start, $end) = split /\-/, $item;
checknum($start);
checknum($end);
$end++;
if ($start >= $end) {
warn "$me: invalid byte list\n";
exit EX_FAILURE;
}
}

# change cut's list parameters to substr's parameters
$start--; # cut counts from 1, not 0
$start = 0 if $start < 0;
$end = $start + 1 unless $item =~ /-/;
$start = length if $start > length;
$end = length if $end > length;

if ($end) {
$end = length if $end > length;
printf ("%s", substr ($_, $start, $end - $start));
} else {
printf ("%s", substr ($_, $start));
}
printf "%s", substr($_, $start - 1, $end - $start);
}
print "\n";
}
Expand All @@ -100,13 +112,6 @@ if (defined ($opt{b})) {
elsif (defined ($opt{f})) {

my @list = split (/,/, $opt{f});
foreach my $item (@list) {
if ($item == 0) {
warn "$me: fields are numbered from 1\n";
exit EX_FAILURE;
}
}

my $delim = "\t";
$delim = substr ($opt{d}, 0, 1) if defined $opt{d};

Expand All @@ -116,17 +121,26 @@ elsif (defined ($opt{f})) {
# Only waste time on lines with delimiters
if (/$delim/) {
foreach my $item (@list) {
my ($start,$end) = split (/-/, $item);
if ($start and $end and $start > $end) {
my ($start, $end);
if (substr($item, 0, 1) eq '-') {
checknum($item);
$start = 0;
$end = abs $item;
} elsif (index($item, '-') == -1) {
checknum($item);
$start = $item - 1;
$end = $start + 1;
} else {
($start, $end) = split /\-/, $item;
checknum($start);
checknum($end);
$start--;
if ($start >= $end) {
warn "$me: invalid field list\n";
exit EX_FAILURE;
}
}

# change cut's list parameters to substr's parameters
$start--; # cut counts from 1, not 0
$start = 0 if $start < 0;
$end = $start + 1 unless $item =~ /-/;

my @hunk = split (/$delim/, $_);

# don't let parameters exceed number of fields
Expand Down