# DF-0072 — REPRODUCED (source-only, root-only checkpoint restore)

## Verdict
REPRODUCED (source-only, root-only checkpoint restore)

## Mechanism
elf_getfiles: filecount=filehdr.cfh_nfiles (int ckpt.h:47) used as kmalloc(filecount*sizeof(ckpt_fileinfo),M_WAITOK) at :599 with no sign/magnitude check. Negative → SIZE_MAX kmalloc M_WAITOK → panic/hang.

## Source trace
- File: `sys/kern/kern_checkpoint.c`
- References: sys/kern/kern_checkpoint.c:598, sys/kern/kern_checkpoint.c:599

## 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
Validate filecount >= 0 and upper-bound (1024) plus a SIZE_MAX/sizeof guard before the kmalloc. Matches finding proposal.