| Subject: | Broken Captcha Image on UI if generated code matches code in db |
Environment Details
-----------------------------------
Distribution name and version: Authen-Captcha-1.023
]$ perl -v
This is perl, v5.8.8 built for x86_64-linux-thread-multi
...
]$ uname -a
Linux dev01.ds.dev.corp.oversee.net 2.6.18-164.11.1.el5 #1 SMP Wed Jan 20 07:32:21 EST
2010 x86_64 x86_64 x86_64 GNU/Linux
Bug Reproduction Details
-------------------------------------------
Initial State of db -
]$ cat /remote/captcha/db/codes.txt
1349114291::0c3035c07ffd2fb0908a93c8f0755252
Application code -
# new instance
my $captcha = Authen::Captcha->new(
data_folder => ’/remote/captcha/db’,
output_folder => ’/remote/captcha/img’,
expire => '600',
);
Then we generate a 4 digit code
my $md5sum = $captcha->generate_code('4');
Now, if lets say $md5sum happens to be 0c3035c07ffd2fb0908a93c8f0755252 then Line #
359 of Captcha.pm removes the $png_file and inserts a new line in the db along with the #
current timestamp at Line 370. This leaves the db in an inconsistent state and a broken
image on the UI ( image not found issue ).
Patch - Attaching a Captcha.pm.patch
-------------------------------------------------------------
In case of an expired db code, the fix removes the png file only for non dupe. Down below, it
appends the db with a new line and current timestamp for a non dupe.
In case of a db code which is not expired, it keeps the current line in the db. Down below, it
skips appending the db for a dupe.
| Subject: | Captcha.pm.patch |
--- /usr/lib/perl5/site_perl/5.8.6/Authen/Captcha.pm 2003-12-17 20:44:34.000000000 -0800
+++ /home/vshah/Captcha.pm 2012-10-01 12:16:11.000000000 -0700
@@ -348,17 +348,23 @@
close(DATA);
my $new_data = "";
+ my $duplicate_md5 = 0;
foreach my $line (@data)
{
$line =~ s/\n//;
my ($data_time,$data_code) = split(/::/,$line);
- if ( (($current_time - $data_time) > ($self->expire())) ||
- ($data_code eq $md5) )
- { # remove expired captcha, or a dup
- my $png_file = File::Spec->catfile($self->output_folder(),$data_code . ".png");
- unlink($png_file) or carp("Can't remove png file [$png_file]\n");
+ if ( ($current_time - $data_time) > ($self->expire()) )
+ { # expired, remove the line for non dupes only
+ if( $data_code ne $md5 ) {
+ my $png_file = File::Spec->catfile($self->output_folder(),$data_code . ".png");
+ unlink($png_file) or carp("Can't remove png file [$png_file]\n");
+ }
} else {
+ # not expired, keep the line
$new_data .= $line."\n";
+ if( $data_code eq $md5 ) {
+ $duplicate_md5 = 1; # do not write a new line below
+ }
}
}
@@ -367,9 +373,11 @@
open(DATA,">$database_file") or die "Can't open File: $database_file\n";
flock DATA, 2; # write lock
warn "-->>" . $new_data . "\n" if($self->debug() >= 2);
- warn "-->>" . $current_time . "::" . $md5."\n" if($self->debug() >= 2);
print DATA $new_data;
- print DATA $current_time."::".$md5."\n";
+ unless( $duplicate_md5 ) {
+ warn "-->>" . $current_time . "::" . $md5."\n" if($self->debug() >= 2);
+ print DATA $current_time."::".$md5."\n";
+ }
close(DATA);
warn "Close File: $database_file\n" if($self->debug() >= 2);
@@ -491,7 +499,6 @@
my $code = $self->generate_random_string($length);
my $md5 = md5_hex($code);
-
my ($captcha_data_ref,$output_filename);
if ($self->type() eq 'image')
{