fix(userspace/engine): replace invalid chars while JSON-encoding

[ekoops]

What type of PR is this?

Uncomment one (or more) /kind <> lines:

/kind bug

/kind cleanup

/kind design

/kind documentation

/kind failing-test

/kind feature

/kind release

Any specific area of the project related to this PR?

Uncomment one (or more) /area <> lines:

/area build

/area engine

/area tests

/area proposals

/area CI

What this PR does / why we need it:

This PR adds a second layer of sanitization in code encoding the output as JSON. The main sanitization issues should have been already addressed in libs (see falcosecurity/libs#2965): this second layer just ensures Falco doesn't crash if we missed something there.

I want to thank again https://github.com/naokato for discovering the issue and helping us with fixing it 🙏 .

Which issue(s) this PR fixes:

Related to falcosecurity/libs#2965

Fixes #

Special notes for your reviewer:

/milestone 0.44.0

Does this PR introduce a user-facing change?:

NONE

[github-actions]

This PR may bring feature or behavior changes in the Falco engine and may require the engine version to be bumped.

Please double check userspace/engine/falco_engine_version.h file. See versioning for FALCO_ENGINE_VERSION.

/hold

[irozzo-1A]

/lgtm

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ekoops, irozzo-1A, leogr

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• OWNERS [ekoops,leogr]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ekoops]

This PR may bring feature or behavior changes in the Falco engine and may require the engine version to be bumped.

Please double check userspace/engine/falco_engine_version.h file. See versioning for FALCO_ENGINE_VERSION.

/hold

False positive.
/hold cancel