| <!-- | |
| Creating a security policy that fits your specific local environment | |
| before making use of ImageMagick is highly advised. You can find guidance on | |
| setting up this policy at https://imagemagick.org/script/security-policy.php, | |
| and it's important to verify your policy using the validation tool located | |
| at https://imagemagick-secevaluator.doyensec.com/. | |
| Open ImageMagick security policy: | |
| The default policy for ImageMagick installations is the open security | |
| policy. This policy is designed for usage in secure settings like those | |
| protected by firewalls or within Docker containers. Within this framework, | |
| ImageMagick enjoys broad access to resources and functionalities. This policy | |
| provides convenient and adaptable options for image manipulation. However, | |
| it's important to note that it might present security vulnerabilities in | |
| less regulated conditions. Thus, organizations should thoroughly assess | |
| the appropriateness of the open policy according to their particular use | |
| case and security prerequisites. | |
| ImageMagick security policies in a nutshell: | |
| Domains include system, delegate, coder, filter, module, path, or resource. | |
| Rights include none, read, write, execute and all. Use | to combine them, | |
| for example: "read | write" to permit read from, or write to, a path. | |
| Use a glob expression as a pattern. | |
| Suppose we do not want users to process MPEG video images, use this policy: | |
| <policy domain="delegate" rights="none" pattern="mpeg:decode" /> | |
| Here we do not want users reading images from HTTP: | |
| <policy domain="coder" rights="none" pattern="HTTP" /> | |
| The /repository file system is restricted to read only. We use a glob | |
| expression to match all paths that start with /repository: | |
| <policy domain="path" rights="read" pattern="/repository/*" /> | |
| Prevent users from executing any image filters: | |
| <policy domain="filter" rights="none" pattern="*" /> | |
| Cache large images to disk rather than memory: | |
| <policy domain="resource" name="area" value="1GP"/> | |
| Use the default system font unless overridden by the application: | |
| <policy domain="system" name="font" value="/usr/share/fonts/favorite.ttf"/> | |
| Define arguments for the memory, map, area, width, height and disk resources | |
| with SI prefixes (.e.g 100MB). In addition, resource policies are maximums | |
| for each instance of ImageMagick (e.g. policy memory limit 1GB, -limit 2GB | |
| exceeds policy maximum so memory limit is 1GB). | |
| Rules are processed in order. Here we want to restrict ImageMagick to only | |
| read or write a small subset of proven web-safe image types: | |
| <policy domain="delegate" rights="none" pattern="*" /> | |
| <policy domain="filter" rights="none" pattern="*" /> | |
| <policy domain="coder" rights="none" pattern="*" /> | |
| <policy domain="coder" rights="read|write" pattern="{GIF,JPEG,PNG,WEBP}" /> | |
| See https://imagemagick.org/script/security-policy.php for a deeper | |
| understanding of ImageMagick security policies. | |
| --> | |
| <policymap> | |
| <policy domain="Undefined" rights="none"/> | |
| <!-- Set maximum parallel threads. --> | |
| <!-- <policy domain="resource" name="thread" value="2"/> --> | |
| <!-- Set maximum time to live in seconds or mnemonics, e.g. "2 minutes". When | |
| this limit is exceeded, an exception is thrown and processing stops. --> | |
| <!-- <policy domain="resource" name="time" value="120"/> --> | |
| <!-- Set maximum number of open pixel cache files. When this limit is | |
| exceeded, any subsequent pixels cached to disk are closed and reopened | |
| on demand. --> | |
| <!-- <policy domain="resource" name="file" value="768"/> --> | |
| <!-- Set maximum amount of memory in bytes to allocate for the pixel cache | |
| from the heap. When this limit is exceeded, the image pixels are cached | |
| to memory-mapped disk. --> | |
| <!-- <policy domain="resource" name="memory" value="256MiB"/> --> | |
| <!-- Set maximum amount of memory map in bytes to allocate for the pixel | |
| cache. When this limit is exceeded, the image pixels are cached to | |
| disk. --> | |
| <!-- <policy domain="resource" name="map" value="512MiB"/> --> | |
| <!-- Set the maximum width * height of an image that can reside in the pixel | |
| cache memory. Images that exceed the area limit are cached to disk. --> | |
| <!-- <policy domain="resource" name="area" value="16KP"/> --> | |
| <!-- Set maximum amount of disk space in bytes permitted for use by the pixel | |
| cache. When this limit is exceeded, the pixel cache is not be created | |
| and an exception is thrown. --> | |
| <!-- <policy domain="resource" name="disk" value="1GiB"/> --> | |
| <!-- Set the maximum length of an image sequence. When this limit is | |
| exceeded, an exception is thrown. --> | |
| <!-- <policy domain="resource" name="list-length" value="32"/> --> | |
| <!-- Set the maximum width of an image. When this limit is exceeded, an | |
| exception is thrown. --> | |
| <!-- <policy domain="resource" name="width" value="8KP"/> --> | |
| <!-- Set the maximum height of an image. When this limit is exceeded, an | |
| exception is thrown. --> | |
| <!-- <policy domain="resource" name="height" value="8KP"/> --> | |
| <!-- Periodically yield the CPU for at least the time specified in | |
| milliseconds. --> | |
| <!-- <policy domain="resource" name="throttle" value="2"/> --> | |
| <!-- Do not create temporary files in the default shared directories, instead | |
| specify a private area to store only ImageMagick temporary files. --> | |
| <!-- <policy domain="resource" name="temporary-path" value="/magick/tmp/"/> --> | |
| <!-- Force memory initialization by memory mapping select memory | |
| allocations. --> | |
| <!-- <policy domain="cache" name="memory-map" value="anonymous"/> --> | |
| <!-- Ensure all image data is fully flushed and synchronized to disk. --> | |
| <!-- <policy domain="cache" name="synchronize" value="true"/> --> | |
| <!-- Replace passphrase for secure distributed processing --> | |
| <!-- <policy domain="cache" name="shared-secret" value="secret-passphrase" stealth="true"/> --> | |
| <!-- Do not permit any delegates to execute. --> | |
| <!-- <policy domain="delegate" rights="none" pattern="*"/> --> | |
| <!-- Do not permit any image filters to load. --> | |
| <!-- <policy domain="filter" rights="none" pattern="*"/> --> | |
| <!-- Don't read/write from/to stdin/stdout. --> | |
| <!-- <policy domain="path" rights="none" pattern="-"/> --> | |
| <!-- don't read sensitive paths. --> | |
| <!-- <policy domain="path" rights="none" pattern="/etc/*"/> --> | |
| <!-- Indirect reads are not permitted. --> | |
| <!-- <policy domain="path" rights="none" pattern="@*"/> --> | |
| <!-- These image types are security risks on read, but write is fine --> | |
| <!-- <policy domain="module" rights="write" pattern="{MSL,MVG,PS,SVG,URL,XPS}"/> --> | |
| <!-- This policy sets the number of times to replace content of certain | |
| memory buffers and temporary files before they are freed or deleted. --> | |
| <!-- <policy domain="system" name="shred" value="1"/> --> | |
| <!-- Enable the initialization of buffers with zeros, resulting in a minor | |
| performance penalty but with improved security. --> | |
| <!-- <policy domain="system" name="memory-map" value="anonymous"/> --> | |
| <!-- Set the maximum amount of memory in bytes that are permitted for | |
| allocation requests. --> | |
| <!-- <policy domain="system" name="max-memory-request" value="256MiB"/> --> | |
| </policymap> | |