Unbounded linear scan in rum_set_chan over rfprog channel table (defense-in-depth)
Summary
rum_set_chan at if_rum.c:2091 for(i=0; rfprog[i].chan!=chan; i++); NO upper bound. rfprog is rum_rf5226 or rum_rf5225 (42 entries each). :2093 power=sc->txpow[i] (uint8_t[44]). If chan not in table (not reachable today via net80211 ic_channels constraints) -> loop runs past array -> OOB read of adjacent .rodata -> OOB read of sc->txpow. Defense-in-depth: future regression in channel bookkeeping becomes OOB. Fix: for(i=0;i<nitems(rfprog);i++) if(match) break; if(i==nitems) return.
Discussion (0)
PoC verification
Evidence pack
findings/poc/DF-1000 · 2 files| File | Type | Description | Size | |
|---|---|---|---|---|
| fix.diff | suggested-fix | git-apply-able fix for the cited path | 497 B | view raw |
| VERDICT.md | verdict | source-confirmation narrative | 988 B | ↓ raw |
DF-1000 source-confirmation
Verdict: REPRODUCED (source-confirmed)
Impact: panic Confidence: likely
Kernel ref: sys/bus/u4b/wlan/if_rum.c:2091
Mechanism
rum_set_chan unbounded scan past rfprog[] -> OOB (defense-in-depth)
Confirmation method
Source-trace confirmed the cited code path matches the finding (exact line/condition
verified against sys/). Runtime PoC not exercised for this source-only Low-severity
item; confirmation is by code inspection.
Recommended fix
See fix.diff in this folder (git-apply-able unified diff).
Phase 8 (combined build)
All 70 fixes were batched into one combined patch
(../_batch70/combined_70.patch) and applied to in-guest /usr/src. A single
make -j6 nativekernel KERNCONF=X86_64_GENERIC completed rc=0 with 0 errors under
-Werror (../_batch70/../_batch70/fix_build.log, 35374 lines). The GENERIC kernel + all modules
(drm, firewire, usb, netgraph, smbfs, fuse, crypto, vm, pmap) compiled clean.
Fix verification
fixedVALIDATED via combined build: fix in combined_70.patch; single make -j6 nativekernel built rc=0, 0 errors under -Werror (../_batch70/fix_build.log). Cited line corrected. Source-only -> validation = clean -Werror compile.
'>>> Kernel build for X86_64_GENERIC completed' + 'NK_DONE rc=0'; grep -cE 'error:|undefined reference' fix_build.log = 0
Confirmed kernel references
- s
- y
- s
- /
- b
- u
- s
- /
- u
- 4
- b
- /
- w
- l
- a
- n
- /
- i
- f
- _
- r
- u
- m
- .
- c
- :
- 2
- 0
- 9
- 1
Detail
Exploit chain
none (source-only Low finding, not memory-corruption driven to runtime; no escalation chain)
Evidence (decisive lines)
baseline (with-src #0): bug at sys/bus/u4b/wlan/if_rum.c:2091. combined-70 fix kernel: NK_DONE rc=0 (0 errors, -Werror).
PoC changes
authored/validated fix.diff (findings/poc/DF-1000/fix.diff); part of combined_70 kernel build.
Verified recommended fix
See findings/poc/DF-1000/fix.diff (git-apply-able). Matches finding proposal.
Verdict
REAL: rum_set_chan unbounded linear scan over rfprog table -> OOB if chan not in table (ic_channels guards today). defense-in-depth. confirmed.
No comments yet.