Android (Termux): every confined file operation fails with EACCES — open_confined opens / with O_RDONLY|O_DIRECTORY, which SELinux denies to apps #6980

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1. github-project-automation

   added this to CodeWhaleon Oct 14, 2026
2. github-project-automation

   moved this to Backlog in CodeWhaleon Oct 14, 2026
3. github-actions

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   needs-triageNew external report awaiting maintainer triage; repro, logs and version output helpNew external report awaiting maintainer triage; repro, logs and version output help

   on Oct 14, 2026
4. printf033 commented on Oct 14, 2026

   

   printf033

   on Oct 14, 2026

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   Attaching the minimal reproducer inline (single file, no deps; run with python3 android-repro.py inside Termux):

   #!/usr/bin/env python3
   """Minimal reproducer: confined open fails on Android/Termux, O_PATH fixes it.
   
   Run inside any Termux (or other untrusted_app SELinux domain) shell:
   
       python3 android-repro.py
   
   Expected on an affected device:
       open(/, O_RDONLY|O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC) -> EACCES   <-- codewhale 0.10.1 open_confined()
       open(/, O_PATH|O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC)   -> OK       <-- proposed fix
       confined read after fix: OK
   
   On a normal Linux box both opens succeed and the script prints OK for all.
   """
   import os
   import sys
   
   O_RDONLY = os.O_RDONLY
   O_DIRECTORY = os.O_DIRECTORY
   O_NOFOLLOW = os.O_NOFOLLOW
   O_CLOEXEC = os.O_CLOEXEC
   O_PATH = getattr(os, "O_PATH", 0o10000000)
   
   WORKSPACE = os.getcwd()
   TARGET_REL = ".codewhale/android-repro-probe"
   
   
   def try_open(path, flags):
       try:
           fd = os.open(path, flags)
           os.close(fd)
           return True, None
       except OSError as e:
           return False, e
   
   
   def confined_walk_opath(workspace, relative):
       """The proposed open_confined(): O_PATH anchor + O_PATH components."""
       anchor = os.open("/", O_PATH | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC)
       fd = anchor
       try:
           for comp in workspace.strip("/").split("/"):
               fd = os.open(comp, O_PATH | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC, dir_fd=fd)
           parts = relative.strip("/").split("/")
           for comp in parts[:-1]:
               try:
                   fd = os.open(comp, O_PATH | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC, dir_fd=fd)
               except FileNotFoundError:
                   os.mkdir(comp, 0o700, dir_fd=fd)   # mirrors the mkdirat branch
                   fd = os.open(comp, O_PATH | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC, dir_fd=fd)
           # materialize the final parent as a real directory fd
           real = os.open(".", O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC, dir_fd=fd)
           return real
       finally:
           os.close(fd)
   
   
   def main():
       print(f"workspace: {WORKSPACE}")
   
       ok, err = try_open("/", O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC)
       print(f"open('/', O_RDONLY|O_DIRECTORY)  [current open_confined anchor]: "
             f"{'OK' if ok else f'FAIL errno={err.errno} ({err.strerror})'}")
   
       ok, err = try_open("/", O_PATH | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC)
       print(f"open('/', O_PATH|O_DIRECTORY)    [proposed fix anchor]:        "
             f"{'OK' if ok else f'FAIL errno={err.errno} ({err.strerror})'}")
   
       try:
           real = confined_walk_opath(WORKSPACE, TARGET_REL)
       except OSError as e:
           print(f"confined walk (fix):             FAIL errno={e.errno} ({e.strerror})")
           return 1
       print("confined walk (fix):             OK")
   
       # full confined write + read through the fixed walk
       leaf = TARGET_REL.split("/")[-1]
       fd = os.open(leaf, os.O_RDWR | os.O_CREAT | os.O_EXCL | O_NOFOLLOW | O_CLOEXEC,
                    0o600, dir_fd=real)
       os.write(fd, b"probe")
       os.fsync(fd)
       os.close(fd)
       fd = os.open(leaf, os.O_RDONLY | O_NOFOLLOW | O_CLOEXEC, dir_fd=real)
       data = os.read(fd, 5)
       os.close(fd)
       os.unlink(leaf, dir_fd=real)
       os.fsync(real)
       os.close(real)
   
       if data != b"probe":
           print("confined write/read:             FAIL (content mismatch)")
           return 1
       print("confined write/read through fix: OK")
       return 0
   
   
   if __name__ == "__main__":
       sys.exit(main())

   Expected output on an affected device:

   workspace: /data/data/com.termux/files/home
   open('/', O_RDONLY|O_DIRECTORY)  [current open_confined anchor]: FAIL errno=13 (Permission denied)
   open('/', O_PATH|O_DIRECTORY)    [proposed fix anchor]:        OK
   confined walk (fix):             OK
   confined write/read through fix: OK
   
5. Hmbown commented on Oct 15, 2026

   

   Hmbown

   on Oct 15, 2026

   Last edited by Hmbown

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   🤖 This reply is from Claude Opus 5.5, an AI agent working on behalf of the Codewhale maintainers. It is posted through @Hmbown's account, but Hunter did not write it.

   Thank you @printf033 — the strace line, the SELinux domain readback and the standalone reproducer make this an unusually clean diagnosis. I confirmed on current main that WorkspaceFile::open_confined still anchors at open("/", O_RDONLY|O_DIRECTORY|…) (crates/tui/src/fleet/files.rs:122) and opens every intermediate component with the same flags, so a search-only domain fails before the walk reaches the workspace.

   Your proposed shape (O_PATH for the anchor and intermediate components, then reopening the final parent as a real directory fd for fsync/renameat/unlinkat) is the direction we'd take. Would you open it as a PR against main so it lands under your name? Two things to keep in mind: O_PATH exists only on Linux/Android, so the change needs to be cfg-gated with macOS/BSD keeping today's flags; and the reopen of the final parent should keep O_NOFOLLOW/O_CLOEXEC. Nothing is shipped yet. This is not in 0.10.2 until a PR lands and passes CI on all three OSes, and we can't verify on an Android device ourselves, so your on-device check of the PR build would be the acceptance evidence.

   — Written by Claude Opus 5.5 (AI agent) on behalf of the maintainers.
6. github-project-automation

   moved this from Backlog to In progress in CodeWhaleon Oct 15, 2026
7. Hmbown

   closed this as completedin #6983on Oct 15, 2026
8. Hmbown

   added a commit that references this issue on Oct 15, 2026

   fix(tui): open confined paths with O_PATH anchors on Linux so Android…

   ...

   3317db7
9. github-project-automation

   moved this from In progress to Done in CodeWhaleon Oct 15, 2026