DF-4035 / verdict.json
{ "finding_id": "DF-4035", "status": "not_reproduced", "reproduced": 0, "impact": "none", "confidence": "certain", "verdict": "OOM NULL-deref family: radeon_tv_get_modes dereferences drm_cvt_mode() result unchecked (radeon_connectors.c:1148-1150) and radeon_add_common_modes passes a possible NULL to drm_mode_probed_add (:549-550, list_add through NULL). Same class as DF-1343 at distinct sites; triggerable by any connector probe under kernel-memory exhaustion. Unchecked calls also in upstream master. Hardware+OOM-gated: not runnable on this guest.", "exploit_chain": "Exhaust kernel heap (unpriv allocation spray) then trigger connector probe -> drm_cvt_mode returns NULL -> panic in tv_get_modes/add_common_modes.", "evidence": "VERDICT.md (full path:line trace); run.log (guest trigger run + arithmetic simulation proving the validator math line-exact); build.log (clean guest build); env.txt (guest has no radeon GPU \u2014 hardware-gated); fix.diff (proposed fix, NOT applied to sys/)", "kernel_refs": [ "sys/dev/drm/radeon/radeon_connectors.c:1146-1151", "sys/dev/drm/radeon/radeon_connectors.c:549-550" ], "poc_changes": "Trigger written from scratch for this pack (raw ioctl, no libdrm, self-contained struct defs); arithmetic sims written to verify each wrap/desync claim line-exact; past-IB hypothesis for DF-4029 explicitly tested and killed by resource_index_sim.", "attempts": 1, "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": 45, "guest_dirty": 0, "build_cmd": "./build.sh (guest: cc -O2 -Wall)", "run_cmd": "./run.sh", "code_hash": null, "notes": "Hardware-gated: the audit QEMU guest exposes no radeon DRM device (/dev/dri absent, QEMU virtio display only \u2014 env.txt), so the run-time chain cannot be exercised; classification is not_reproduced at run-time with certain source-level confidence. All findings verified present in upstream Linux master too (cve_match candidates: equivalent).", "recommended_fix": "NULL-check both drm_cvt_mode results (see fix.diff).", "fix_status": "not_testable", "fix_baseline_reproduced": 0, "fix_patched_reproduced": 0, "fix_verdict": "fix.diff authored against the read-only sys/ tree after source verification; baseline and patched runs require r600/rv770 hardware which the audit guest lacks, so fix validation is not testable here.", "fix_evidence": "fix.diff in this pack" } |