⬢ DragonFlyBSD Kernel Audit
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DF-0322

No validation of tid/baw before indexing ni_rx_ampdu[tid] and setting rxa_wnd

Summary

ieee80211_ampdu_rx_start_ext(:566) comment XXX TODO: sanity check tid,seq,baw. tid indexes ni_rx_ampdu[tid] no [0,16) bound. baw is int: negative baw -> min(neg,64)=neg -> uint16 conversion -> huge rxa_wnd -> all off<rxa_wnd checks pass -> rxa_m[off] heap OOB write. Driver-gated.

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PoC verification

Evidence pack

findings/poc/DF-0322 · 5 files
FileTypeDescriptionSize
fix.diff suggested-fix git-apply-able fix for DF-0322 409 B view raw
VERDICT.md verdict source-confirmation + fix summary 661 B ↓ raw
build.sh build-log combined-build validation note 333 B view raw
run.sh run-log source-only (no runtime PoC) 147 B view raw
env.txt environment guest uname + build env 218 B view raw
VERDICT.md verdict source-confirmation + fix summary
↓ download raw

DF-0322 -- Low

Verdict: REPRODUCED (source-confirmed)

REAL: ieee80211_ampdu_rx_start_ext has the author's own XXX TODO to sanity-check tid/seq/baw; tid indexes ni_rx_ampdu[tid] with no [0,16) bound and baw is int -- a negative baw -> min(neg,64)=neg -> uint16 rxa_wnd -> huge -> rxa_m[off] heap OOB write. Driver-gated.

Impact ceiling

none

Cited refs

Fix

Validate tid in [0, WME_NUM_TID) and clamp baw>=0 before use.

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/netproto/802_11/wlan/ieee80211_ht.c:570 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/netproto/802_11/wlan/ieee80211_ht.c:570; combined-fix kernel 'NK_DONE rc=0' (0 errors,-Werror).

PoC changes

authored fix.diff (findings/poc/DF-0322/fix.diff); validated in the combined 60-finding kernel build.

Verified recommended fix

Validate tid in [0, WME_NUM_TID) and clamp baw>=0 before use. Full diff: findings/poc/DF-0322/fix.diff.

Verdict

REAL: ieee80211_ampdu_rx_start_ext has the author's own XXX TODO to sanity-check tid/seq/baw; tid indexes ni_rx_ampdu[tid] with no [0,16) bound and baw is int -- a negative baw -> min(neg,64)=neg -> uint16 rxa_wnd -> huge -> rxa_m[off] heap OOB write. Driver-gated.