Summary

mfi_tbolt.c:471-480 error path frees slots + pool, sets sc->mfi_cmd_pool_tbolt=NULL, but NO return -> falls through to next loop iteration writing sc->mfi_cmd_pool_tbolt[i] = kmalloc() through NULL pointer. Also line 455 request_desc_pool = kmalloc(...) has NO NULL check but is derefed at 502. Trigger: memory pressure during mfi Thunderbolt attach (M_NOWAIT fails). Fix: return 1 from error path + check request_desc_pool NULL.

PoC verification

Evidence pack

findings/poc/DF-1583 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	270 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-1583 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: mfi_tbolt.c:471-480 error path frees slots + pool, sets sc->mfi_cmd_pool_tbolt=NULL, but NO return -> falls through to next loop iteration writing sc->mfi_cmd_pool_tbolt[i] = kmalloc() through NULL po

Citation: sys/dev/raid/mfi/mfi_tbolt.c:455-480

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: missing return after freeing pool — falls through writing NULL[i] (mfi_tbolt.c:471-480)

Verified recommended fix

Source-confirmed: missing return after freeing pool — falls through writing NULL[i] (mfi_tbolt.c:471-480)

Verdict