DF-1584

mfi_build_and_issue_cmd leaks Thunderbolt command slot on mfi_tbolt_build_io failure

Summary

mfi_tbolt.c:1097 cmd=mfi_tbolt_get_cmd removes cmd from free pool. 1105-1106 if(mfi_tbolt_build_io(...)) return NULL WITHOUT mfi_tbolt_return_cmd(sc,cmd). cmd permanently lost from both free and busy lists. mfi_tbolt_build_io returns 1 for every MFI_CMD_LD_SCSI_IO (mfi_tbolt_is_ldio false at 907 -> else return 1 at 910) AND for sge_count > mfi_max_sge (917-921). After mfi_max_fw_cmds LD_SCSI_IO commands pool drains -> DF-1582 NULL-deref panic. Fix: mfi_tbolt_return_cmd(sc,cmd) before return NULL.

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Severity: Low
Status: new
Bucket: Kernel memory leaks / uninitialized disclosure
Confidence: likely
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U:C:N/I:N/A:H
CWE: CWE-401 Missing Release of Memory after Effective Lifetime
File: sys/dev/raid/mfi/mfi_tbolt.c
Lines: 1097-1106
Area: dev
Discovered: 2026-07-18
Updated: 2026-07-18

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: leak
Confidence: likely
Tested: 2026-07-23 17:00:06
Attempts: —
Runtime: —
Code hash: —
Guest: DragonFly dfbsd 6.5-DEVELOPMENT #0
Build cmd: —
Run cmd: —

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Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: likely
Tested: 2026-07-23 17:00:06
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1584/fix.diff
Runner: df-bsd-pocrunner

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PoC verification

Evidence pack

findings/poc/DF-1584 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	449 B	view raw
VERDICT.md	verdict	source-confirmation analysis	710 B	↓ raw
build.sh	build-script	N/A (source-only)	61 B	view raw
run.sh	run-script	N/A (source-only)	87 B	view raw

VERDICT.md verdict source-confirmation analysis

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DF-1584 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: mfi_tbolt.c:1097 cmd=mfi_tbolt_get_cmd removes cmd from free pool. 1105-1106 if(mfi_tbolt_build_io(...)) return NULL WITHOUT mfi_tbolt_return_cmd(sc,cmd). cmd permanently lost from both free and busy

Citation: sys/dev/raid/mfi/mfi_tbolt.c:1097-1106

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 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: cmd leaked from pool when mfi_tbolt_build_io fails (mfi_tbolt.c:1105-1106)

Verified recommended fix

Source-confirmed: cmd leaked from pool when mfi_tbolt_build_io fails (mfi_tbolt.c:1105-1106)

Verdict

Source-confirmed: cmd leaked from pool when mfi_tbolt_build_io fails (mfi_tbolt.c:1105-1106)