DF-1592

Unvalidated csio->cdb_len overflows cmd_pkt->cmd.pkt_a.cdb[16] in tws_execute_scsi

Summary

tws_cam.c:757-758 #ifdef TWS_DEBUG only traces cdb_len>16. 761-764 bcopy(csio->cdb_io.cdb_bytes, cmd_pkt->cmd.pkt_a.cdb[16], csio->cdb_len). csio->cdb_len u8 (0..255) fully user-controlled via pass(4) CAMIOCOMMAND. Production build NO bound check. cdb[16] at tws_hdm.h:325. cdb_len>16 -> writes past cdb[] into sg_list[744]/padding region of DMA cmd_pkt. Operator group /dev/passN. CAM_DIR_NONE path: corrupted sg_list bytes survive. Sibling of DF-1547 (advansys). Fix: reject cdb_len > sizeof(cdb).

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Severity: Low
Status: new
Bucket: Kernel memory corruption (UAF / OOB write)
Confidence: certain
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:L/A:L
CWE: CWE-787 Out-of-bounds Write
File: sys/dev/raid/tws/tws_cam.c
Lines: 757-764
Area: dev
Discovered: 2026-07-18
Updated: 2026-07-18

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: panic
Confidence: certain
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: certain
Tested: 2026-07-23 17:00:06
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1592/fix.diff
Runner: df-bsd-pocrunner

jump to fix verification ↓

PoC verification

Evidence pack

findings/poc/DF-1592 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	656 B	view raw
VERDICT.md	verdict	source-confirmation analysis	706 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

↓ download raw

DF-1592 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: tws_cam.c:757-758 #ifdef TWS_DEBUG only traces cdb_len>16. 761-764 bcopy(csio->cdb_io.cdb_bytes, cmd_pkt->cmd.pkt_a.cdb[16], csio->cdb_len). csio->cdb_len u8 (0..255) fully user-controlled via pass(4)

Citation: sys/dev/raid/tws/tws_cam.c:757-764

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: unvalidated csio->cdb_len overflows cmd_pkt->cdb[16] (tws_cam.c:761-764)

Verified recommended fix

Source-confirmed: unvalidated csio->cdb_len overflows cmd_pkt->cdb[16] (tws_cam.c:761-764)

Verdict

Source-confirmed: unvalidated csio->cdb_len overflows cmd_pkt->cdb[16] (tws_cam.c:761-764)