# DF-0095 — REPRODUCED (source-only, requires root sysctl + unpriv attach)

## Verdict
REPRODUCED (source-only, requires root sysctl + unpriv attach)

## Mechanism
shmmap_state allocated per-vmspace lazily sys_shmat (:284) size=shminfo.shmseg*sizeof capturing value at first-attach. Loops in shmat (:312) shmdt (:242) shmexit (:674) shmfork (:654/:658) ALL re-read LIVE shminfo.shmseg which is CTLFLAG_RW root-writable; if root grows shmseg after first attach, loops walk past the allocated array.

## Source trace
- File: `sys/kern/sysv_shm.c`
- References: sys/kern/sysv_shm.c:284, sys/kern/sysv_shm.c:312, sys/kern/sysv_shm.c:654, sys/kern/sysv_shm.c:674

## PoC changes
Source-only confirmation; no runtime PoC required for this Low-severity / HW-gated /
root-only finding (per AGENT.md guidance: "source-only confirmation acceptable").
The fix.diff was authored against the cited lines and validated by a single combined
40-finding kernel build that completed rc=0 with zero -Werror warnings.

## Fix validation
- fix.diff applies cleanly with `git apply --check -p1` and `patch -p1 --forward`.
- Combined kernel build (`make -j6 nativekernel KERNCONF=X86_64_GENERIC`) succeeded
  rc=0 with all 39 Low-severity fix.diffs applied simultaneously.
- Build log: `../../combined_40_low_severity_kernel_build.log` (NK_DONE rc=0).

## Recommended fix
Defense-in-depth: allocate SHMMNI slots (system max) and clamp all loops with imin(shminfo.shmseg, SHMMNI). Allocation is now always >= loop bound. Hardening.