convert:not authorized `aaaa` @ error/constitute.c/ReadImage/453

Question

I want to create a captcha pic by use convert from ImageMagick.

And I follow this, but there are some problem .

Input In my linux shell:

Answer 1

Note: the solution in this and other answers involves disabling safety measures that are there to fix arbitrary code execution vulnerabilities. See for instance this ghostscript-related and this ubuntu-related announcement. Only go forward with these solutions if the input to convert comes from a trusted source.

I use ImageMagick in php (v.7.1) to slice PDF file to images.

First I got errors like:

Exception type: ImagickException

Exception message: not authorized ..... @ error/constitute.c/ReadImage/412

After some changes in /etc/ImageMagick-6/policy.xml I start getting erroes like:

Exception type: ImagickException

Exception message: unable to create temporary file ..... Permission denied @ error/pdf.c/ReadPDFImage/465

My fix:

In file /etc/ImageMagick-6/policy.xml (or /etc/ImageMagick/policy.xml)

1. comment line

2. change line

   to

3. add line

Then restart your web server (nginx, apache).