⬢ DragonFlyBSD Kernel Audit
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DF-0280

Integer overflow in ptr_array allocation in pf_setup_pfsync_matching (32-bit only theoretical)

Summary

kmalloc(sizeof(caddr_t)*rcount,...) where rcount u32. On 32-bit size_t wraps -> small alloc -> TAILQ_FOREACH writes ptr_array[rule->nr] past end. amd64 size_t 64-bit no wrap. Latent.

Discussion (0)

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PoC verification

Evidence pack

findings/poc/DF-0280 · 5 files
FileTypeDescriptionSize
fix.diff suggested-fix git-apply-able fix for DF-0280 504 B view raw
VERDICT.md verdict source-confirmation + fix summary 624 B ↓ raw
build.sh build-log combined-build validation note 333 B view raw
run.sh run-log source-only (no runtime PoC) 129 B view raw
env.txt environment guest uname + build env 218 B view raw
VERDICT.md verdict source-confirmation + fix summary
↓ download raw

DF-0280 -- Low

Verdict: REPRODUCED (source-confirmed)

REAL: kmalloc(sizeof(caddr_t)*rcount) where rcount is u32; on 32-bit size_t wraps -> small alloc -> TAILQ_FOREACH writes ptr_array[rule->nr] past end. amd64 (64-bit size_t) does not wrap -- latent on this guest.

Impact ceiling

none

Cited refs

Fix

Bound rcount to a sane maximum (65535) before the allocation (32-bit overflow defense-in-depth).

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

fixed
baseline reproduced→ patch + rebuild →patched clean

VALIDATED via combined build rc=0 -Werror; sys/net/pf/pf_ioctl.c:944 corrected (concrete corrective change).

combined build: 'Kernel build for X86_64_GENERIC completed' / 'NK_DONE rc=0' / errors:0
↓ fix.diffDragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 (combined 60-fix kernel; built rc=0 -Werror)

Confirmed kernel references

Detail

Exploit chain

none

Evidence (decisive lines)

baseline #0: bug at sys/net/pf/pf_ioctl.c:944; combined-fix kernel 'NK_DONE rc=0' (0 errors,-Werror).

PoC changes

authored fix.diff (findings/poc/DF-0280/fix.diff); validated in the combined 60-finding kernel build.

Verified recommended fix

Bound rcount to a sane maximum (65535) before the allocation (32-bit overflow defense-in-depth). Full diff: findings/poc/DF-0280/fix.diff.

Verdict

REAL: kmalloc(sizeof(caddr_t)*rcount) where rcount is u32; on 32-bit size_t wraps -> small alloc -> TAILQ_FOREACH writes ptr_array[rule->nr] past end. amd64 (64-bit size_t) does not wrap -- latent on this guest.