DF-1636

Memory leak of priv struct on early error paths before dm_table_init_target

Summary

dm_target_crypt.c:489 priv=kmalloc. 492 dm_pdev_insert fail -> return ENOENT no kfree(priv). 500 crypto_cipher==NULL -> goto notsup; notsup at 584 only frees status_str. dm_table_init_target (513) NOT yet called -> table_en->target_config still NULL -> dm_table_destroy NULL guard skips cleanup. priv leaked ~640B per call. Trigger: repeated DM_TABLE_LOAD with bad dev path or unsupported cipher (rot13-cbc). Heap exhaustion DoS. Fix: kfree(priv) on pre-513 error paths.

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Severity: Low
Status: new
Bucket: Kernel memory leaks / uninitialized disclosure
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:N/A:L
CWE: CWE-401 Missing Release of Memory after Effective Lifetime
File: sys/dev/disk/dm/crypt/dm_target_crypt.c
Lines: 489-587
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: certain
Tested: 2026-07-23 17:00:09
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 17:00:09
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1636/fix.diff
Runner: df-bsd-pocrunner

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PoC verification

Evidence pack

findings/poc/DF-1636 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	762 B	view raw
VERDICT.md	verdict	source-confirmation analysis	719 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-1636 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: dm_target_crypt.c:489 priv=kmalloc. 492 dm_pdev_insert fail -> return ENOENT no kfree(priv). 500 crypto_cipher==NULL -> goto notsup; notsup at 584 only frees status_str. dm_table_init_target (513) NOT

Citation: sys/dev/disk/dm/crypt/dm_target_crypt.c:489-587

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: priv struct leaked on dm_pdev_insert/crypto_cipher fail (dm_target_crypt.c:489-500)

Verified recommended fix

Source-confirmed: priv struct leaked on dm_pdev_insert/crypto_cipher fail (dm_target_crypt.c:489-500)

Verdict

Source-confirmed: priv struct leaked on dm_pdev_insert/crypto_cipher fail (dm_target_crypt.c:489-500)