DF-5569 / verdict.json
{ "finding_id": "DF-5569", "status": "untested", "reproduced": false, "impact": "none", "confidence": "likely", "verdict": "DRIVERSLEEP() at sys/platform/vkernel64/platform/systimer.c:358-367 evaluates 1000000/usec without guarding usec==0, an integer division by zero that would surface as a SIGFPE-driven vkernel panic. Latent only: the sole in-tree callers (aps.c:200,224; psm.c:865) pass nonzero constants and none of those drivers attach in a VKERNEL64 kernel, and pc64s twin (clock.c:485) has no division at all. Filed as Info hardening; no runtime trigger exists in this platform, so no PoC was run (the arithmetic defect itself is plain C semantics).", "exploit_chain": "", "evidence": "Source-only: systimer.c:363 (1000000 / usec), caller census via rg DRIVERSLEEP sys/ (aps.c:200/224, psm.c:865, pc64 clock.c:485), README.md fix sketch.", "kernel_refs": [ "sys/platform/vkernel64/platform/systimer.c:358", "sys/platform/vkernel64/platform/systimer.c:363", "sys/platform/pc64/isa/clock.c:485" ], "poc_changes": "n/a (not executed)", "attempts": 0, "guest_uname": "DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64", "runtime_sec": 0, "guest_dirty": 0, "build_cmd": "", "run_cmd": "", "code_hash": "", "notes": "Info-severity hardening finding; per audit contract Low/Info findings are not PoC-verified. Secondary note in README.md: the 1000000/usec >= hz condition is inverted relative to the sleep-long/spin-short intent.", "recommended_fix": "Guard DRIVERSLEEP against usec <= 0 before dividing (see README.md diff); consider matching pc64s division-free twin.", "fix_status": "not_testable", "fix_baseline_reproduced": false, "fix_patched_reproduced": false, "fix_verdict": "Not validated on the guest: no VKERNEL64 kernel calls DRIVERSLEEP(), so neither baseline nor patched behavior is observable; the guard is trivially correct by inspection.", "fix_evidence": "README.md fix sketch; caller census in README.md" } |