dirfs_setattr chtimes ignores the requested va_atime/va_mtime entirely — lutimes(path, NULL) always stamps 'now' (utimensat/UTIME_OMIT semantics unimplemented)
Summary
The chtimes branch of dirfs_setattr (:556-568) passes the vnode to dirfs_node_chtimes, which calls lutimes(tmp, NULL) (dirfs_subr.c:661) - the times the caller supplied in vap are never read. Every utimes/utimensat/futimens on a dirfs file silently degrades to a 'touch'. Permission checking happens correctly at the syscall layer (NLC_OWN|NLC_WRITE), so this is a contract/integrity bug - the inverse-direction sibling of tmpfs DF-3024. Timestamp-sensitive tooling silently misbehaves on dirfs (tar -m/rsync -t restores, make -t, incremental backups - mtimes forged to 'now', defeating mtime-based change detection). Fix: pass the requested times through (tv[2] from vap, VA_UTIMES_NULL -> NULL) or fail EOPNOTSUPP on explicit times. [VERIFIED pass2: dead code same as DF-3058; chtimes contract breach code-certain]
Discussion (0)
PoC verification
Evidence pack
findings/poc/DF-3059 · 7 files| File | Type | Description | Size | |
|---|---|---|---|---|
| README.md | — | 287 B | ↓ raw | |
| VERDICT.md | — | 916 B | ↓ raw | |
| env.txt | — | 248 B | view raw | |
| fix.diff | — | 144 B | view raw | |
| manifest.json | — | 593 B | view raw | |
| run.log | — | 197 B | view raw | |
| verdict.json | — | 1.1 KB | view raw |
DF-3059 - dirfs_setattr chtimes ignores requested atime/mtime (always stamps now)
Severity Low | verdict: not_reproduced | impact: none
Reproduce
No runnable PoC on this rig (see VERDICT.md for why).
See VERDICT.md for the full narrative and run.log for the decisive output.
DF-3059 verification
Kernel: DragonFly dfbsd 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64
Not executable on this rig for the same reason as DF-3058: dirfs is dead code (no Makefile, not built into any kernel or module, mount_dirfs refuses real kernels), so the lutimes(path, NULL)-always behavior (dirfs_subr.c:661 via dirfs_vnops.c:556-568) could not be exercised. Code-certain contract breach.
Kernel references
Fix
See fix.diff.
Fix status (batch validation)
Applied with the 36 sibling fix.diffs of this batch in findings/poc/_batch41/all_fixes.patch; single in-guest make -j6 nativekernel KERNCONF=X86_64_GENERIC completed RC=0 with zero errors under -Werror (full log: findings/poc/_batch41/fix_build8.log). Behavior A/B intentionally skipped for this Info-tier item.
Fix verification
not_testableConfirmed kernel references
Detail
Evidence (decisive lines)
VERDICT.md + run.log + sources
PoC changes
none
Verified recommended fix
diff: build tv[2] from vap->va_atime/va_mtime (VA_UTIMES_NULL -> NULL) and pass to lutimes; fail EOPNOTSUPP on explicit times if unsupported.
Verdict
Not executable on this rig for the same reason as DF-3058: dirfs is dead code (no Makefile, not built into any kernel or module, mount_dirfs refuses real kernels), so the lutimes(path, NULL)-always behavior (dirfs_subr.c:661 via dirfs_vnops.c:556-568) could not be exercised. Code-certain contract breach.
No comments yet.