Summary

tws_ctlr_reset L471-475 stage-1 do{reg=tws_read_reg(TWS_I2O0_SCRPD3)}while(reg&TWS_BIT13) no timeout. Next stage L477-481 correctly bounded TWS_RESET_TIMEOUT plainly oversight. Runtime reachable: tws_reset tws_cam.c:1198 -> tws_reinit tws_cam.c:1242 recovery retry re-asserts soft reset; callout-driven recovery after timeout tws_cam.c:1185 microcontroller error tws_cam.c:1144-1153. Malicious controller holds TWS_BIT13 wedges callout thread blocks softclock DoS. Fix: TWS_LOCAL_TIME+TWS_RESET_TIMEOUT return false.

PoC verification

Evidence pack

findings/poc/DF-1925 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	460 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-1925 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: tws_ctlr_reset L471-475 stage-1 do{reg=tws_read_reg(TWS_I2O0_SCRPD3)}while(reg&TWS_BIT13) no timeout. Next stage L477-481 correctly bounded TWS_RESET_TIMEOUT plainly oversight. Runtime reachable: tws_

Citation: sys/dev/raid/tws/tws_hdm.c:473-475

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: do{}while(TWS_BIT13) no timeout in ctlr_reset (tws_hdm.c:473-475)

Verified recommended fix

Source-confirmed: do{}while(TWS_BIT13) no timeout in ctlr_reset (tws_hdm.c:473-475)

Verdict