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DF-0263

ICMP-error NAT for other protocol corrupts inner source (copy-paste bug)

Summary

pf_test_state_icmp default inner-proto case: guard tests pd2.dst(:5732) but calls pf_change_icmp(pd2.src,...)(:5734) should be pd2.dst. ICMPv6 inner case(:5635-5643) correct. Copy-paste from source branch. Inner dest untranslated + inner source overwritten. Remote: ICMP error embedding non-TCP/UDP/ICMP packet on NAT state.

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PoC verification

Evidence pack

findings/poc/DF-0263 · 5 files
FileTypeDescriptionSize
fix.diff suggested-fix git-apply-able fix for DF-0263 362 B view raw
VERDICT.md verdict source-confirmation + fix summary 604 B ↓ raw
build.sh build-log combined-build validation note 333 B view raw
run.sh run-log source-only (no runtime PoC) 148 B view raw
env.txt environment guest uname + build env 218 B view raw
VERDICT.md verdict source-confirmation + fix summary
↓ download raw

DF-0263 -- Low

Verdict: REPRODUCED (source-confirmed)

REAL: pf_test_state_icmp default inner-proto case guards on pd2.dst (line 5732) but calls pf_change_icmp(pd2.src,...) (line 5734) -- copy-paste. Inner dest untranslated + source overwritten. Remote ICMP error.

Impact ceiling

none

Cited refs

Fix

Change the first pf_change_icmp arg from pd2.src to pd2.dst.

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.c:5732 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.c:5732; combined-fix kernel 'NK_DONE rc=0' (0 errors,-Werror).

PoC changes

authored fix.diff (findings/poc/DF-0263/fix.diff); validated in the combined 60-finding kernel build.

Verified recommended fix

Change the first pf_change_icmp arg from pd2.src to pd2.dst. Full diff: findings/poc/DF-0263/fix.diff.

Verdict

REAL: pf_test_state_icmp default inner-proto case guards on pd2.dst (line 5732) but calls pf_change_icmp(pd2.src,...) (line 5734) -- copy-paste. Inner dest untranslated + source overwritten. Remote ICMP error.