Kernel heap info leak via oversized copyout of unzeroed outbuffer
Summary
hptrr_osm_bsd.c:1265 kmalloc(nOutBufferSize, M_DEVBUF, M_WAITOK) NO M_ZERO. ldm writes only required bytes per ioctl. 1273-1277 copyout(lpOutBuffer, user, nOutBufferSize) copies FULL user-supplied size -> unwritten tail exposes stale M_DEVBUF heap. Trigger: HPT_IOCTL_GET_CONTROLLER_INFO with nOutBufferSize=4096. Root only. Twin of DF-1565 (hpt27xx). Fix: M_ZERO on kmalloc or cap copyout to bytesReturned.
Discussion (0)
PoC verification
Evidence pack
findings/poc/DF-1580 · 4 files| File | Type | Description | Size | |
|---|---|---|---|---|
| fix.diff | suggested-fix | git-apply-able fix for the cited bug | 468 B | view raw |
| VERDICT.md | verdict | source-confirmation analysis | 1.0 KB | ↓ raw |
| build.sh | build-script | N/A (source-only) | 65 B | view raw |
| run.sh | run-script | N/A (source-only) | 89 B | view raw |
DF-1580 VERDICT
Verdict: REPRODUCED (source-confirmed)
Impact: Low (driver-level NULL deref / OOB / leak / DoS — hardware-gated)
Mechanism: hptrr_osm_bsd.c:1265 kmalloc(nOutBufferSize, M_DEVBUF, M_WAITOK) NO M_ZERO. ldm writes only required bytes per ioctl. 1273-1277 copyout(lpOutBuffer, user, nOutBufferSize) copies FULL user-supplied siz
Citation: sys/dev/raid/hptrr/hptrr_osm_bsd.c:1266-1277
Fix: Applied fix.diff — compiles in batch kernel build (rc=0, -Werror).
Verification method: Source-only line-by-line trace of cited path:line. Low-severity driver bug; PoC trigger requires specific hardware or root context. Confirmed the cited vulnerable pattern exists in source.
Fix status (batch validation)
Applied with the 36 sibling fix.diffs of this batch in findings/poc/_batch41/all_fixes.patch; single in-guest make -j6 nativekernel KERNCONF=X86_64_GENERIC completed RC=0 with zero errors under -Werror (full log: findings/poc/_batch41/fix_build8.log). Behavior A/B intentionally skipped for this Info-tier item.
Fix verification
fixedfix.diff compiled in batch kernel build rc=0 -Werror
fix.diff compiled in batch kernel build rc=0 -Werror
Confirmed kernel references
—
Detail
Exploit chain
none (Low severity)
Evidence (decisive lines)
Source-confirmed: kmalloc without M_ZERO + full-size copyout leaks heap (hptrr_osm_bsd.c:1265,1273)
Verified recommended fix
Source-confirmed: kmalloc without M_ZERO + full-size copyout leaks heap (hptrr_osm_bsd.c:1265,1273)
Verdict
Source-confirmed: kmalloc without M_ZERO + full-size copyout leaks heap (hptrr_osm_bsd.c:1265,1273)
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