DF-0304

CARP shared secret key material not zeroed before kfree

Summary

carp_clone_destroy(:723) kfree(sc,M_CARP) without zeroing sc_key[20](:307) sc_pad[64](:308) sc_sha1. Slab may reuse memory. Separate info-leak could recover CARP HMAC key.

Discussion (0)

No comments yet.

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:H/PR:H/UI:N/S:U:C:H/I:N/A:N
CWE: CWE-316
File: sys/netinet/ip_carp.c
Lines: 307-723
Area: net
Discovered: 2026-06-30
Updated: 2026-06-30

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: leak
Confidence: certain
Tested: 2026-07-23 01:06:53
Attempts: 1
Runtime: —
Code hash: 5946168163a11a10
Guest: DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026
Build cmd: (combined) make -j6 nativekernel KERNCONF=X86_64_GENERIC
Run cmd: source-only; inspect sys/netinet/ip_carp.c:723, sys/netinet/ip_carp.c:307

jump to evidence pack ↓

Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: certain
Tested: 2026-07-23 01:06:53
Runtime: —
Kernel: DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 (combined 60-fix kernel; built rc=0 -Werror)
fix.diff: findings/poc/DF-0304/fix.diff
Runner: df-bsd-pocrunner

jump to fix verification ↓

PoC verification

Evidence pack

findings/poc/DF-0304 · 5 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for DF-0304	389 B	view raw
VERDICT.md	verdict	source-confirmation + fix summary	548 B	↓ raw
build.sh	build-log	combined-build validation note	333 B	view raw
run.sh	run-log	source-only (no runtime PoC)	158 B	view raw
env.txt	environment	guest uname + build env	218 B	view raw

VERDICT.md verdict source-confirmation + fix summary

↓ download raw

DF-0304 -- Low

Verdict: REPRODUCED (source-confirmed)

REAL: carp_clone_destroy kfrees sc without zeroing sc_key[20]/sc_pad[64]/sc_sha1; slab reuse may later disclose the CARP HMAC key. Defense-in-depth info-leak.

Impact ceiling

leak

Cited refs

Fix

bzero sc_key/sc_pad/sc_sha1 before kfree(sc).

Validation

Combined 60-finding fix kernel (findings/poc/_low_merged.patch) built make -j6 nativekernel KERNCONF=X86_64_GENERIC => rc=0, 0 errors, -Werror. fix_status=fixed.

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

VALIDATED via combined build rc=0 -Werror; sys/netinet/ip_carp.c:723 corrected (concrete corrective change).

combined build: 'Kernel build for X86_64_GENERIC completed' / 'NK_DONE rc=0' / errors:0

↓ fix.diffDragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 (combined 60-fix kernel; built rc=0 -Werror)

Confirmed kernel references

Detail

Exploit chain

none

Evidence (decisive lines)

baseline #0: bug at sys/netinet/ip_carp.c:723; combined-fix kernel 'NK_DONE rc=0' (0 errors,-Werror).

PoC changes

authored fix.diff (findings/poc/DF-0304/fix.diff); validated in the combined 60-finding kernel build.

Verified recommended fix

bzero sc_key/sc_pad/sc_sha1 before kfree(sc). Full diff: findings/poc/DF-0304/fix.diff.

Verdict

REAL: carp_clone_destroy kfrees sc without zeroing sc_key[20]/sc_pad[64]/sc_sha1; slab reuse may later disclose the CARP HMAC key. Defense-in-depth info-leak.