[MIR] Promote ruby-childprocess as a pcs dependency

Review for Package: src:ruby-childprocess

[Summary]
ruby-childprocess is a widely used ruby gem for inter process communication
between parent/child processes.

MIR team ACK under the constraint to resolve the below listed
required TODOs and as much as possible having a look at the
recommended TODOs.

This does need a security review, so I'll assign ubuntu-security

List of specific binary packages to be promoted to main: ruby-childprocess
Specific binary packages built, but NOT to be promoted to main: <None>

Notes:
- This is handling process IO between unknown/untrused processes. Therefore,
  I'll subscribe ~ubuntu-security

Required TODOs:
#0 get ruby-ffi promoted, MIR bug #1990570
#1 The server team still needs to subscribe to the package before promotion

Recommended TODOs:
- None

[Duplication]
There is no other package in main providing the same functionality.

[Dependencies]
OK:
- no -dev/-debug/-doc packages that need exclusion
- No dependencies in main that are only superficially tested requiring
  more tests now.

Problems:
- needs ruby-ffi MIR: bug #1990570

[Embedded sources and static linking]
OK:
- no embedded source present
- no static linking
- does not have unexpected Built-Using entries
- not a go package, no extra constraints to consider in that regard
- not a rust package, no extra constraints to consider in that regard

Problems: None

[Security]
OK:
- history of CVEs does not look concerning
- does not run a daemon as root
- does not use webkit1,2
- does not use lib*v8 directly
- does not process arbitrary web content
- does not use centralized online accounts
- does not integrate arbitrary javascript into the desktop
- does not deal with system authentication (eg, pam), etc)
- does not deal with security attestation (secure boot, tpm, signatures)
- does not deal with cryptography (en-/decryption, certificates, signing, ...)

Problems:
- opens an IPC channel (pipe) between parent and child processes
- parses generic process input/ouput (stdin/stdout/stderr)

[Common blockers]
OK:
- does not FTBFS currently
- does have a test suite that runs at build time
  - test suite fails will fail the build upon error.
- does have a non-trivial test suite that runs as autopkgtest
- no new python2 dependency
- not a python package
- not a go package

Problems: None

[Packaging red flags]
OK:
- Ubuntu does not carry a delta
- symbols tracking not applicable for this kind of code.
  (it's a ruby module/gem, not a binary library)
- d/watch is present and looks ok (if needed, e.g. non-native)
- Upstream update history is slow, but OK for this type of software
- Debian/Ubuntu update history is slow, but OK for this type of software
- the current release is packaged
- promoting this does not seem to cause issues for MOTUs that so far
  maintained the package
- no massive Lintian warnings
- d/rules is rather clean
- It is not on the lto-disabled list

Problems: None

[Upstream red flags]
OK:
- no Errors/warnings during the build
- no incautious use of malloc/sprintf (as far as we can check it)
- no use of sudo, gksu, pkexec, or LD_LIBRARY_PATH (usage is OK inside tests)
- no use of user nobody
- no use of setuid
- no important open bugs (c...

Thanks for the review Lukas!

#0 ruby-ffi got ACKed by the MIR team.

#1 Server team will be subscribed before its promotion.

I reviewed ruby-childprocess 4.1.0-1 as checked into kinetic. This shouldn't be considered a full audit but rather a quick gauge of maintainability.

> Cross-platform Ruby library for managing child processes.

- CVE History:
  - none
    - CVE-2021-23352 is not related to Ruby or ruby-childprocess
  - upstream GitHub issue tracker is extremely well maintained
  - no Security Policy and no contact info in README
- Build-Depends?
  - lunar main
     - debhelper-compat (debhelper)
     - glibc (locales-all)
     - procps
  - lunar universe
     - gem2deb
     - ruby-rspec
     - ruby-coveralls
     - ruby-ffi
     - yard
- pre/post inst/rm scripts?
  - none
- init scripts?
  - none
- systemd units?
  - none
- dbus services?
  - none
- setuid binaries?
  - none
- binaries in PATH?
  - none
- sudo fragments?
  - none
- polkit files?
  - none
- udev rules?
  - none
- unit tests / autopkgtests?
  - has autopkgtests
    - passing for >= jammy
  - contains some build tests
- cron jobs?
  - cron
- Build logs:
  - nothing significant

- Processes spawned?
  - childprocess has many process functions
    - e.g.,
      - ./lib/childprocess.rb defines close_on_exec()
      - ./lib/childprocess/unix/fork_exec_process.rb
      - ./lib/childprocess/unix/posix_spawn_process.rb
  - exit result checks could be added
    - e.g., will a forked process run properly if @io or @cwd are false?
      - these modules _should_ exist, what happens when `if` statements are removed
  - generator.rb's execute() compiles arbitrary C code
    - assuming this is trusted input
    - downstream MIRs must be check if input is safe
  - otherwise looks okay
- Memory management?
  - heavy use of FFI
  - commit d9b1580 is for Rubinus only
  - allocating memory size appears safe
- File IO?
  - FileActions class wraps file IO functions
    - part of library
  - PosixSpawnProcess and Generator class' file use looks safe
- Logging?
  - raises FFI errors where pertinent
  - errors defined in lib/childprocess/errors.rb
- Environment variable usage?
  - env variables are managed when forking processes
  - generator reads CC
- Use of privileged functions?
  - none
- Use of cryptography / random number sources etc?
  - none
- Use of temp files?
  - none
- Use of networking?
  - none
- Use of WebKit?
  - none
- Use of PolicyKit?
  - none

- Any significant cppcheck results?
  - none
- Any significant Coverity results?
  - none
- Any significant shellcheck results?
  - none
- Any significant bandit results?
  - none
- Any significant rubocop results?
  - none
    - rubocop complains about eval in spec files

Project is well maintained. Some error message include a url asking users to file GitHub issues, +1

Many functions, such as close_on_exec(), support using jruby. jruby is listed as a requirement in upstream's README. It is not part of the d/control. Files dedicated to jruby in ruby-childprocess require java. Comments in the code mention that jruby has edgecases that need to be handled. jruby exclusive code was not reviewed. I tested a patch that removed lib/childprocess/jruby* and it built--no further testing was attempting. Please consider removing jruby.

ruby-childprocess' generator.rb i...

Showing up in component mismatch now as planned.

Promoted together with the full PCS stack, details see https://bugs.launchpad.net/ubuntu/+source/pcs/+bug/1953341/comments/13