DF-2444 / verdict.json
{ "status": "reproduced", "reproduced": 1, "impact": "none", "confidence": "certain", "verdict": "dm_dev_create on the EEXIST path hands out a pointer to freed memory: production call #1 (name df2444x) returned 0; production call #2 with the same name returned EEXIST (17) AND set the out-parameter dmv=0xfffff8008de708c0 - the object dm_dev_destroy just destroyed (dm_dev.c:264-267: destroy then *dmvp = dmv). Currently benign: the sole caller checks r != 0 and never touches *dmvp, so no corruption is reachable today; the defect is a latent caller-side UAF API hazard.", "exploit_chain": "", "evidence": "run.log (r1=0 / r2=17 with non-NULL stale out-param)", "kernel_refs": [ "sys/dev/disk/dm/dm_dev.c:264", "sys/dev/disk/dm/dm_dev.c:267", "sys/dev/disk/dm/dm_ioctl.c:213" ], "poc_changes": "direct production dm_dev_create calls from the rig (dm.ko symbol)", "attempts": 1, "runtime_sec": 120, "guest_dirty": 0, "build_cmd": "see build.sh (dfmisc.ko + dm.ko)", "run_cmd": "sysctl kern.dfmiscgo=dmeexist", "notes": "root-only ioctl surface (dmsetup)", "recommended_fix": "set *dmvp = dmv only on success (move the assignment above the insert-failure destroy, or NULL it on failure)", "finding_id": "DF-2444", "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", "runner": "df-bsd-reviewer", "code_hash": "69dbf9bb5732f0ffe7e8a8490d8ed55c8857a4b293df8c6abf21c24ee3c297c5" } |