setrread.blogg.se - Imagemagic current comfig

IMAGEMAGIC CURRENT COMFIG PDF
IMAGEMAGIC CURRENT COMFIG CODE

In the best case users have root access and can change the policy for everyone on the system, then other apps and users could become exploitable because the default system policy is now too lax. If I can run commands on the system I should be able to override the system policy. So I should lobby my distribution to either ship that version or lock down any methods by which a user could compile ImageMagick locally, I guess :-) With that build option, ImageMagick will allow the security policy to be overridden by any policy in the paths you mention in your post.

ImageMagick has an uninstalled build option. "/usr/bin/convert.safe" which could be whitelisted so it is allowed to be run by a web server, but having behavior as a default for local users feels like something Mordac the preventor of information services would come up with.Ī non-default -unsafe flag which prevents the uninformed user from accidentally running commands which might be harmful would be reasonable. This is why /usr/bin/passwd requests the old password for normal users first, but not for root (which could just write directly to /etc/shadow anyhow).

just running a user-compiled version of convert,Ī "security" policy which is trivial to circumvent is generally just an annoyance.

use a debugger to make the policy-checking method return the desired result or.

using LD_PRELOAD to redirect the open("etc/ImageMagick-6/policy.xml").

directly parsing pdfs directly with ghostscript.

If convert was installed with the setuid bit, then it would certainly have to enforce system-wide limits against the user, but last time I checked it is generally not.įrom my understanding, nothing prevents the user from:

IMAGEMAGIC CURRENT COMFIG CODE

root does not configure specific permissions for bash, python or gcc or any of the myriad other programs which can be used to execute arbitrary code (including form unsafe sources, e.g. On a unixish system, the standard assumption is that a user may generally arbitrary code with that users permission. administrator sets a memory limit of 2GB, the user can set a limit of 1GB but not 3GB). In certain cases, the user can set certain resource limits but only a lesser value that what the administrator sets (e.g. If ImageMagick is installed, only the policy in the system path is enforced, otherwise it would not be much of a security policy if it could easily be overridden. Environment (Operating system, version and so on): Ubuntu 16.04.4.I have also tried to place the policy file in the from where I call the convert command, it also appears when I execute convert -list policy, but I still get the not authorized error unless I changed the global policy file.

IMAGEMAGIC CURRENT COMFIG PDF

If I change the policy file in /etc/ImageMagick-6/policy.xml to allow reading PDF files, my convert command works.