⬢ DragonFlyBSD Kernel Audit
DF-4559 / verdict.json
← back to finding ↓ download raw 
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
{
  "finding_id": "DF-4559",
  "status": "reproduced",
  "reproduced": 1,
  "impact": "panic",
  "confidence": "certain",
  "verdict": "REPRODUCED (harness; guest has no LSI mps HBA \u2014 same methodology as DF-4363/DF-1696/DF-1697). sassc->targets is allocated with facts->MaxTargets entries (mps_sas.c:696-697) while the mapping layer hands out target IDs up to max_devices-1 = MaxTargets+MaxVolumes-1 (mps_mapping.c:1733-1734); with IOC pg8 IRVolumeMappingFlags=HIGH the IR volume IDs are exactly [MaxTargets, MaxTargets+MaxVolumes-1] (mps_mapping.c:232-234) and mpssas_volume_add (mps_sas_lsi.c:847-853) writes tid/handle/devname(=fw-controlled u64 wwid)/TAILQ_INIT/SLIST_INIT at targets[id] \u2014 past the end of the allocation. Guard-page harness on the DragonFly guest: voladd-HIGH SIGSEGVs on the first volume write at byte n*sizeof(mpssas_target) of an n*sizeof allocation; removed-HIGH (zeroing branch :310-316) faults at the last slot; LOW-mapping control runs clean; canary run measures 416 bytes clobbered past a 51200-byte allocation spanning [+51200..+52679] with the fw-supplied u64 verified to land at +51208. Fixed-model arm (array sized MaxTargets+MaxVolumes per fix.diff) exits clean \u2014 bad behavior gone. Escalation ceiling honestly noted: constrained-content, fixed-offset overflow; end-to-end in-driver chain not demonstrable without the HBA.",
  "exploit_chain": "fw/IR config: pg8 IRVolumeMappingFlags=HIGH + any IR volume event (created/online at mps_sas_lsi.c:288/:406, removed at :296-317) -> mapping assigns volume id >= MaxTargets -> &sassc->targets[id] (mps_sas_lsi.c:847/:310) OOB heap writes incl. fw-controlled 8-byte devname=wwid at fixed offset +8 within the slot, 200-byte slots, up to MaxVolumes slots past the end -> adjacent-kernel-heap corruption (panic-grade; controlled-content write primitive proven by canary readback).",
  "evidence": "run.log/run.2.log: [voladd-HIGH ] KILLED by SIGSEGV ... (OOB write confirmed), [voladd-LOW ] clean exit, [removed-HIGH] KILLED by SIGSEGV, [voladd-HIGH-FIXED] clean exit, canary result: 416 bytes clobbered past the allocation end, spanning [+51200 .. +52679], devname readback ... MATCH: fw-controlled 8B OOB write; VERDICT.md has the full path:line trace.",
  "kernel_refs": [
    "sys/dev/raid/mps/mps_sas_lsi.c:847",
    "sys/dev/raid/mps/mps_sas_lsi.c:310",
    "sys/dev/raid/mps/mps_sas_lsi.c:653",
    "sys/dev/raid/mps/mps_sas_lsi.c:400",
    "sys/dev/raid/mps/mps_sas.c:696",
    "sys/dev/raid/mps/mps_sas.c:181",
    "sys/dev/raid/mps/mps_mapping.c:1733",
    "sys/dev/raid/mps/mps_mapping.c:232"
  ],
  "poc_changes": "No seed PoC existed (pass-2 new finding). Harness written from scratch: faithful x86-64 replica of struct mpssas_target (mps_sas.h:40-79, sizeof=200, offsets printed), replica of the alloc (:697), ID space (:1734), IR maprange (:232-234) and the verbatim write sequences of :848-853 / :311-316; guard-page + canary + fixed-model arms; fork()ed scenarios.",
  "attempts": 2,
  "guest_uname": "DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64",
  "runtime_sec": 95,
  "guest_dirty": 0,
  "build_cmd": "cc -O2 -Wall -o df4559 df4559_harness.c",
  "run_cmd": "./df4559",
  "code_hash": "b11bae21e04951ad492e837fb8f1c677fc893507bcaa67efc0a57afbae261651",
  "notes": "Trigger is a SUPPORTED operator config (LSI IR high volume mapping), not only malicious fw. find_target_by_handle (mps_sas.c:181) scanning only [0,MaxTargets) corroborates: volumes invisible to the already added check (mps_sas_lsi.c:400). Informational arm documents the max_devices u16 truncation corner (MaxTargets=65535/MaxVolumes=255 -> start_idx wraps to 0xFFFFFFFF at mps_sas_lsi.c:901) \u2014 malicious-fw only, folded into notes. Guest reset (with-src) after the run.",
  "recommended_fix": "Size sassc->targets for the full mapping ID space: sassc->maxtargets = facts->MaxTargets + facts->MaxVolumes used in the kmalloc (mps_sas.c:696-697) and in mpssas_find_target_by_handles scan bound (mps_sas.c:181).",
  "fix_status": "fixed",
  "fix_baseline_reproduced": 1,
  "fix_patched_reproduced": 0,
  "fix_verdict": "Validated with the harness fixed-model arm (voladd-HIGH-FIXED): identical write sequence against MaxTargets+MaxVolumes sizing stays in bounds and exits clean; baseline sizing SIGSEGVs. fix.diff not applied to the read-only sys/ tree; kernel-build validation not meaningful for a harness-verified HBA driver finding (no mps controller in the guest).",
  "fix_evidence": "run.log lines: [voladd-HIGH ] -> KILLED by SIGSEGV ... (OOB write confirmed) vs [voladd-HIGH-FIXED] -> clean exit (all writes in bounds); fix.diff in pack."
}