Captchas not being generated in versions > 0.3.2.

[wpp]

Hi there,

After a recent upgrade I noticed that captchas were not showing up:

I didn't see any errors in my server log, but my guess is that the tempfile changes generate_simple_captcha_image might be the problem?

Versions:

• simple_captcha2 0.3.4
• rails 4.2.1.5
• ruby 2.2.4p230
• ImageMagick 6.8.9-9 Q16 x86_64
• Debian GNU/Linux 8.2 (jessie)

Version 0.4.0 had the same problem. Changing the simple_captcha2 version to 0.3.2 "fixed" the issue.

irb(main):001:0> include SimpleCaptcha::ImageHelpers
=> Object
irb(main):002:0> generate_simple_captcha_image('asdf')
  SimpleCaptcha::SimpleCaptchaData Load (1.4ms)  SELECT  `simple_captcha_data`.* FROM `simple_captcha_data` WHERE `simple_captcha_data`.`key` = 'asdf'  ORDER BY `simple_captcha_data`.`id` ASC LIMIT 1
-background '#fff' -fill '#000' -size 100x28 -wave 1x86 -gravity Center -pointsize 22 -implode 0.2 label: -evaluate Uniform-noise 0 jpeg:-
StandardError: Error while running convert: convert: no images defined `jpeg:-' @ error/convert.c/ConvertImageCommand/3210.

    from /usr/local/lib/ruby/gems/2.2.0/gems/simple_captcha2-0.3.4/lib/simple_captcha/utils.rb:17:in `run'
    from /usr/local/lib/ruby/gems/2.2.0/gems/simple_captcha2-0.3.4/lib/simple_captcha/image.rb:83:in `generate_simple_captcha_image'
    from (irb):2
    from /usr/local/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/console.rb:110:in `start'
    from /usr/local/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/console.rb:9:in `start'
    from /usr/local/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:68:in `console'
    from /usr/local/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
    from /usr/local/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands.rb:17:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

[IanBurry]

I'm seeing the same problem

• simple_captcha2 0.4.0
• Rails 4.2.5.1
• ruby 2.1.4p265 (2014-10-27 revision 48166) [x86_64-linux]
• ImageMagick 6.7.7-10 2014-03-06 Q16
• Ubuntu 14.04.1 LTS

However, it's working just fine on my MacBook Pro

• simple_captcha2 0.4.0
• Rails 4.2.2
• ruby 2.2.1p85 (2015-02-26 revision 49769) [x86_64-darwin14]
• ImageMagick 6.9.2-3 Q16 x86_64 2015-10-05
• Mac OS X Yosemite v 10.10.5

[IanBurry]

• simple_captcha2 0.4.0

Looks like the problem is happening when SimpleCaptcha::Utils::run appends '2>&1' to the end of the convert command. Anything on STDERR gets redirected into STDOUT, and borks up the image data stream (if I understand this correctly). It also hides whatever was sent to STDERR.

Removing the redirection resulted in a valid captcha image and the error being displayed in the rails server console:

Fontconfig warning: ignoring C.UTF-8: not a valid language tag

in my case

[zealot128]

hmm interesting, so that bug only happens if there are some encodings wrong, that's why I never ran into it.
I think we could just try to mute the errors in general "> /dev/null" instead. Best option would be using popen3 or similar to seperate the error and stdout stream.

[IanBurry]

@zealot128 I think it's simpler than that. Just let the errors go to stderr instead of redirecting them, then the OS can handle them. Alternately, make the redirection an option, so they can easily be muted.

[Melancholic]

Hello!
Having understood the question, I came to the conclusion that this error was the result of the update of the ImageMagick policy. Link to the relevant news: https://www.imagemagick.org/discourse-server/viewtopic.php?f=4&t=29588.

The following solution helped me:

1. vim /etc/ImageMagick/policy.xml

 50 <policymap>
 51   <!-- <policy domain="system" name="precision" value="6"/> -->
 52   <!-- <policy domain="resource" name="temporary-path" value="/tmp"/> -->
 53   <!-- <policy domain="resource" name="memory" value="2GiB"/> -->
 54   <!-- <policy domain="resource" name="map" value="4GiB"/> -->
 55   <!-- <policy domain="resource" name="area" value="1gb"/> -->
 56   <!-- <policy domain="resource" name="disk" value="16eb"/> -->
 57   <!-- <policy domain="resource" name="file" value="768"/> -->
 58   <!-- <policy domain="resource" name="thread" value="4"/> -->
 59   <!-- <policy domain="resource" name="throttle" value="0"/> -->
 60   <!-- <policy domain="resource" name="time" value="3600"/> -->
 61   <policy domain="coder" rights="none" pattern="EPHEMERAL" />
 62   <policy domain="coder" rights="none" pattern="HTTPS" />
 63   <policy domain="coder" rights="none" pattern="HTTP" />
 64   <policy domain="coder" rights="none" pattern="URL" />
 65   <policy domain="coder" rights="none" pattern="FTP" />
 66   <policy domain="coder" rights="none" pattern="MVG" />
 67   <policy domain="coder" rights="none" pattern="MSL" />
 68   <policy domain="coder" rights="none" pattern="TEXT" />
 69   <!--policy domain="coder" rights="none" pattern="LABEL" /-->         <!--comment this -->
 70   <policy domain="path" rights="none" pattern="@*" />
 71   <policy domain="coder" rights="read | write" pattern="JPEG" />       <!--add this -->
 72   <policy domain="coder" rights="read | write" pattern="PNG" />         <!--add this -->
 73 </policymap>

I'm not sure this solution is safe enough, but it works. If someone can tell how to improve security - I will be grateful. Maybe you need to update README. Thank you!

[jagdeepsingh]

Upgrading imagemagick to version 7.0.7-15 solved the issue for me.

[renji001]

delete '2>&1' worked for me !
imageMagick 6.7.8
fyi