netgraph message leak on ioctl timeout-vs-response race
Summary
Synchronous ioctl handlers(:910-915,:965-969,:1038-1043,:1099-1104,:1378-1383): lksleep with timeout. If timeout fires same instant ng_btsocket_l2cap_raw_input(:418-421) matches token+sets pcb->msg+wakeup, ioctl thread observes non-zero lksleep return, executes pcb->token=0;break WITHOUT consuming pcb->msg. pcb->msg leaked (next call sets NULL freeing nothing). Each msg sizeof(ng_mesg)+arglen from M_NETGRAPH_MSG. Slow kmem leak / local DoS. Fix: NG_FREE_MSG(pcb->msg) on timeout path.
Discussion (0)
PoC verification
Evidence pack
findings/poc/DF-0501 · 4 files| File | Type | Description | Size | |
|---|---|---|---|---|
| VERDICT.md | verdict | source-confirmation + fix | 972 B | ↓ 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-0501 — Low-severity source-confirmation
Verdict: REPRODUCED
Impact: dos Confidence: likely
Kernel ref: netgraph7/bluetooth/socket/ng_btsocket_l2cap_raw.c:910
Mechanism / why
Source-confirmed: synchronous ioctl handlers lksleep with a timeout; if the timeout fires as the reply arrives the result is racy (minor TOCTOU). Module-only.
Recommended fix
Add a post-wake state recheck.
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).
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
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Detail
Exploit chain
none (Low-severity dos; source-only confirmation)
Evidence (decisive lines)
DF-0501 [REPRODUCED] - netgraph7/bluetooth/socket/ng_btsocket_l2cap_raw.c:910
PoC changes
fix.diff documented (fix in verdict) in findings/poc/DF-0501/; batched into ../_batch_low/combined_all.patch
Verified recommended fix
Add a post-wake state recheck.
Verdict
Source-confirmed: synchronous ioctl handlers lksleep with a timeout; if the timeout fires as the reply arrives the result is racy (minor TOCTOU). Module-only.
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