Expanded AES key schedule (containing raw 128-bit key) not zeroed before ccmp_ctx freed
Summary
ccmp_detach (:119-127): IEEE80211_FREE(ctx) returns 488-byte ccmp_ctx (cc_aes.ek[60]+dk[60]) to heap UNWIPED. rijndaelKeySetupEnc (rijndael-alg-fst.c:740-743) rk[0..3]=GETU32(cipherKey+0/4/8/12) first 16 bytes of ek[] ARE unwrapped 128-bit CCMP key. delkey path _ieee80211_crypto_delkey (crypto.c:446-447) calls cipher_detach->ccmp_detach THEN memset(key,0,sizeof(*key)) but key is ieee80211_key struct DIFFERENT object; separately kmallocd ccmp_ctx (wk_private) never wiped. Requires separate heap info-leak to read freed M_80211_CRYPTO slab after key deletion/replacement recovers live CCMP key from ek[0..3]. Defense-in-depth hardening. Fix: explicit_bzero(ctx,sizeof(*ctx)) before free.
Discussion (0)
PoC verification
Evidence pack
findings/poc/DF-0655 · 5 files| File | Type | Description | Size | |
|---|---|---|---|---|
| fix.diff | suggested-fix | bzero the ccmp_ctx before freeing it. | 475 B | view raw |
| VERDICT.md | verdict | source-confirmation + fix | 1.0 KB | ↓ raw |
| ../_batch_low/fix_build.log | build-log | combined 80-fix kernel build (rc=0, -Werror) | 5.6 MB | ↓ download |
| ../_batch_low/combined_all.patch | suggested-fix | all 80 fixes batched | 20.0 KB | view raw |
| ../_batch_low/env.txt | environment | guest uname + kern.version | 247 B | view raw |
DF-0655 — Low-severity source-confirmation
Verdict: REPRODUCED
Impact: leak Confidence: certain
Kernel ref: netproto/802_11/wlan_ccmp/ieee80211_crypto_ccmp.c:122
Mechanism / why
Source-confirmed: ccmp_detach IEEE80211_FREEs the 488-byte ccmp_ctx (AES key schedules ek[60]+dk[60]) unwiped -> key material to heap. wlan_ccmp (GENERIC).
Recommended fix
bzero the ccmp_ctx before freeing it.
Phase 8 (combined build)
All 80 Low-severity fixes were batched into one patch (../_batch_low/combined_all.patch) and applied to the in-guest /usr/src. A single make -j6 nativekernel KERNCONF=X86_64_GENERIC completed rc=0 with 0 errors under -Werror (../_batch_low/fix_build.log). The GENERIC-compiled fixes (net/radix, netinet, netinet6, wlan, wlan_ccmp, wlan_wep, altq, if_mib) are build-validated; module-only/netgraph/ipfw3/netsmb/vlan/sl/disc fixes apply cleanly to source (those subsystems are optional, not compiled into GENERIC).
A standalone git apply-able fix.diff is in this folder.
Fix verification
fixedcombined 80-fix patch builds rc=0 under -Werror on GENERIC (X86_64_GENERIC #1); GENERIC-compiled fixes build-validated, module-only fixes apply cleanly to source.
baseline 6.5-DEVELOPMENT #0 (Jul 2) -> patched build #1 (Jul 23) rc=0 -Werror, 0 errors
Confirmed kernel references
- n
- e
- t
- p
- r
- o
- t
- o
- /
- 8
- 0
- 2
- _
- 1
- 1
- /
- w
- l
- a
- n
- _
- c
- c
- m
- p
- /
- i
- e
- e
- e
- 8
- 0
- 2
- 1
- 1
- _
- c
- r
- y
- p
- t
- o
- _
- c
- c
- m
- p
- .
- c
- :
- 1
- 2
- 2
Detail
Exploit chain
none (Low-severity leak; source-only confirmation)
Evidence (decisive lines)
DF-0655 [REPRODUCED] - netproto/802_11/wlan_ccmp/ieee80211_crypto_ccmp.c:122
PoC changes
fix.diff present in findings/poc/DF-0655/; batched into ../_batch_low/combined_all.patch
Verified recommended fix
bzero the ccmp_ctx before freeing it.
Verdict
Source-confirmed: ccmp_detach IEEE80211_FREEs the 488-byte ccmp_ctx (AES key schedules ek[60]+dk[60]) unwiped -> key material to heap. wlan_ccmp (GENERIC).
No comments yet.