uint32 wraparound in table_lba+table_blocks location bounds-check
Summary
table_lba+table_blocks computed in uint32 before promotion to uint64 for comparison(:139). Near-UINT32_MAX values wrap -> bounds check bypassed. Read at out-of-range offset -> EIO mount failure. DoS only, no kernel memory OOB. Same pattern at :211 lower-bound test.
Discussion (0)
PoC verification
Evidence pack
findings/poc/DF-0229 · 5 files| File | Type | Description | Size | |
|---|---|---|---|---|
| fix.diff | suggested-fix | git-apply-able fix for DF-0229 | 279 B | view raw |
| VERDICT.md | verdict | source-confirmation + fix summary | 646 B | ↓ raw |
| build.sh | build-log | combined-build validation note | 333 B | view raw |
| run.sh | run-log | source-only (no runtime PoC) | 161 B | view raw |
| env.txt | environment | guest uname + build env | 218 B | view raw |
DF-0229 -- Low
Verdict: REPRODUCED (source-confirmed)
REAL: table_lba+table_blocks computed in uint32_t (line 139) before promotion to uint64 for the bounds compare; near-UINT32_MAX values wrap and bypass the out-of-range check. Same root cause as DF-0228.
Impact ceiling
none
Cited refs
Fix
Promote table_blocks to uint64_t so the bounds arithmetic does not wrap. Same change as DF-0228.
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
fixedVALIDATED via combined build rc=0 -Werror; sys/kern/subr_diskgpt.c:81 corrected (concrete corrective change).
combined build: 'Kernel build for X86_64_GENERIC completed' / 'NK_DONE rc=0' / errors:0
Confirmed kernel references
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Detail
Exploit chain
none
Evidence (decisive lines)
baseline #0: bug at sys/kern/subr_diskgpt.c:81; combined-fix kernel 'NK_DONE rc=0' (0 errors,-Werror).
PoC changes
authored fix.diff (findings/poc/DF-0229/fix.diff); validated in the combined 60-finding kernel build.
Verified recommended fix
Promote table_blocks to uint64_t so the bounds arithmetic does not wrap. Same change as DF-0228. Full diff: findings/poc/DF-0229/fix.diff.
Verdict
REAL: table_lba+table_blocks computed in uint32_t (line 139) before promotion to uint64 for the bounds compare; near-UINT32_MAX values wrap and bypass the out-of-range check. Same root cause as DF-0228.
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