GREASE-like support for ipptool and ippserver

[michaelrsweet]

Copied from original ippsample issue 71

Investigate implementing fuzzing and GREASE support into ipptool, specifically for inserting randomized attributes with different names, values, and syntaxes.

Probably there should be a way to insert a random value tag, attribute name, and/or value, plus insert N random attributes.

---

In fuzzing/grease mode we need to make sure we report/record the actual IPP message so that bug reports, etc. can include the full request for testing and debugging.

---

Feedback from morning IPP session:

• Should also include ippserver
• Perhaps use a separate ipptool file generator for the fuzzing
• GREASE support likely needs to be made part of the ipptool/ippserver code (maybe add an API to libcups to append random attributes to the request?)

---

Work list for this bug:

• libcups: new "void ippAddRandomAttributes(ipp_t *ipp)" API for adding random attributes and values to a request or response in current group. Needs to be public API so that servers based on the public API can implement it.
• ipptool: new "-g" (GREASE) option to automatically inject random attributes into every request, and a "GREASE" directive inside test files.
• ippserver: new "-g" (GREASE) option and system.conf "GREASE" directive to enable random attributes in every response.
• Documentation of GREASE extensions

I'll file a separate issue to track a new fuzzing tool.