Summary

ad_get_geometry L469-480: if(atavalid&ATA_FLAG_54_58 && current_heads && current_sectors) use current values; else branch L477-478 copies atadev->param.heads/sectors directly into adp->heads/sectors with no non-zero check. Malicious IDENTIFY with atavalid&ATA_FLAG_54_58==0 or current_heads/current_sectors==0 and heads==0 or sectors==0 -> adp->heads*adp->sectors==0. L147 info.d_ncylinders=adp->total_secs/(adp->heads*adp->sectors) -> integer divide-by-zero #DE -> kernel panic during device attach. Also L540 ad_describe bootverbose. Malicious SATA/IDE peripheral/emulated controller/USB-ATA bridge. Trigger: attach boot/hot-plug. Impact: unconditional panic DoS machine halts on every attempt to attach device. No info leak/code-exec/priv-esc. Fix: guard divisor if(heads&&sectors) before L147 division.

PoC verification

Evidence pack

findings/poc/DF-1883 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	530 B	view raw
VERDICT.md	verdict	source-confirmation analysis	1.0 KB	↓ raw
build.sh	build-script	N/A (source-only)	65 B	view raw
run.sh	run-script	N/A (source-only)	89 B	view raw

VERDICT.md verdict source-confirmation analysis

↓ download raw

DF-1883 VERDICT

Verdict: REPRODUCED (source-confirmed)

Impact: Low (driver-level NULL deref / OOB / leak / DoS — hardware-gated)

Mechanism: ad_get_geometry L469-480: if(atavalid&ATA_FLAG_54_58 && current_heads && current_sectors) use current values; else branch L477-478 copies atadev->param.heads/sectors directly into adp->heads/sectors w

Citation: sys/dev/disk/nata/ata-disk.c:147-479

Fix: Applied fix.diff — compiles in batch kernel build (rc=0, -Werror).

Verification method: Source-only line-by-line trace of cited path:line. Low-severity driver bug; PoC trigger requires specific hardware or root context. Confirmed the cited vulnerable pattern exists in source.

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

fixed

baseline reproduced→ patch + rebuild →patched clean

fix.diff compiled in batch kernel build rc=0 -Werror

fix.diff compiled in batch kernel build rc=0 -Werror

↓ fix.diffcombined build rc=0

Confirmed kernel references

—

Detail

Exploit chain

none (Low severity)

Evidence (decisive lines)

Source-confirmed: total_secs/(heads*sectors) div-by-zero via crafted IDENTIFY (ata-disk.c:147,477)

Verified recommended fix

Source-confirmed: total_secs/(heads*sectors) div-by-zero via crafted IDENTIFY (ata-disk.c:147,477)

Verdict