fix: enforce parent-dir permission check on sysopen O_CREAT#401
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The `elsif` branch in `__sysopen`'s permission check that verified
parent-directory write+execute permission for new file creation was
unreachable dead code. O_CREAT set `contents = ''` before the check,
and the ENOENT guard returned early when contents was undef, so
`defined $mock_file->{'contents'}` was always true at the permission
check.
Fix: capture `$is_new` flag before O_CREAT modifies contents and use
it to route the permission check. Now `sysopen($fh, $path, O_WRONLY|O_CREAT)`
in a read-only directory correctly returns EACCES, matching `open()`
behavior.
Closes cpan-authors#329
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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What
Fix dead
elsifbranch in__sysopenthat silently skipped parent-directory permission checks when creating new files viaO_CREAT.Why
The permission check at the end of
__sysopentesteddefined $mock_file->{'contents'}to distinguish new vs. existing files. But O_CREAT already setcontents = ''earlier in the function, and the ENOENT guard returned early when contents was undef — so theelsifbranch that checks parent-dir write+execute was unreachable. This meantsysopen($fh, '/protected/new', O_WRONLY|O_CREAT)would succeed in a read-only directory underset_user(), while the equivalentopen($fh, '>', '/protected/new')correctly returned EACCES.Issue #329 identified the root cause; issue #330 tracks the broader duplication.
How
Capture
my $is_new = !defined $mock_file->{'contents'}before the O_CREAT block modifies contents. Use$is_new(notdefined contents) to route the permission check: existing files check file-level perms, new files check parent-dir write+execute.Testing
t/perms.t: sysopen O_CREAT in read-only vs. writable parent dir, and sysopen on existing file with file-level perm checkCloses #329
🤖 Generated with Claude Code
Quality Report
Changes: 9 files changed, 118 insertions(+), 1176 deletions(-)
Code scan: clean
Tests: passed (OK)
Branch hygiene: clean
Generated by Kōan post-mission quality pipeline