daioctl uses KKASSERT (debug-only macro) to validate user-controlled DAIOCTRIM alignment -> panic on INVARIANTS, silent bypass on production
Summary
daioctl at scsi_da.c:443-444 KKASSERT((bytes_left%512)==0); KKASSERT((bytes_start%512)==0). bytes_left/bytes_start from user ioctl ap->a_data. KKASSERT panics on INVARIANTS kernels (default X86_64_GENERIC has INVARIANTS); do{}while(0) on non-INVARIANTS -> silent bypass -> misaligned trim proceeds. Root-only (SYSCAP_RESTRICTEDROOT daopen :505). Kernel input validation must never depend on compile-time debug option. Fix: if((bytes_left%512)!=0||(bytes_start%512)!=0) return EINVAL.
Discussion (0)
PoC verification
Evidence pack
findings/poc/DF-1019 · 3 files| File | Type | Description | Size | |
|---|---|---|---|---|
| fix.diff | suggested-fix | git-apply-able fix for the cited path | 476 B | view raw |
| VERDICT.md | verdict | source-confirmation narrative | 922 B | ↓ raw |
| env.txt | environment | guest uname + toolchain | 247 B | view raw |
DF-1019 source-confirmation
Verdict: REPRODUCED (source-confirmed) Impact: none Confidence: likely
Kernel ref: sys/bus/cam/scsi/scsi_da.c:443
Mechanism
daioctl KKASSERT alignment validation: DAIOCTRIM alignment validated only with KKASSERT -> panic on INVARIANTS (default GENERIC), silent bypass on production. root-only; confirmed.
Confirmation method
source-only Low-severity; confirmation by code inspection. Runtime PoC not exercised for this Low-severity item; confirmation is by code inspection against sys/.
Recommended fix
See fix.diff in this folder (git-apply-able unified diff).
Phase 8 (combined build)
This fix is part of the batched 70-finding combined patch
(../_batch70/combined_70.patch) applied to in-guest /usr/src. A single
make -j6 nativekernel KERNCONF=X86_64_GENERIC build is validated rc=0 with 0
errors under -Werror (../_batch70/fix_build.log).
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
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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/cam/scsi/scsi_da.c:443. combined-70 fix kernel: NK_DONE rc=0 (0 errors, -Werror).
PoC changes
authored/validated fix.diff (findings/poc/DF-1019/fix.diff); part of combined_70 kernel build.
Verified recommended fix
See findings/poc/DF-1019/fix.diff (git-apply-able). Matches finding proposal.
Verdict
REAL: daioctl validates DAIOCTRIM alignment only with KKASSERT -> panic on INVARIANTS, silent bypass on production. root-only. confirmed.
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