DF-3044 / manifest.json
{ "finding_id": "DF-3044", "title": "BOOTP/DHCP reply acceptance has zero origin validation and a fully deterministic transaction XID", "manifest_version": 1, "verdict": "reproduced", "impact": "panic", "confidence": "certain", "reproduce": { "build": "on the guest: sh build.sh (sha256-gates bootp_subr.c to the audited tree, adds vfs/nfs/dfrig12_bootp.c via conf/files, make -j6 nativekernel KERNCONF=X86_64_GENERIC && make installkernel; reboot)", "run": "sysctl -w kern.dfrig12=2; sysctl -n kern.dfrig12_status (blind predicted-XID spoof from 6.6.6.6:9999); kern.dfrig12=20 wrong-xid control; on a dedicated boot kern.dfrig12=4 panics via the verbatim decode path", "expected": "test 2 baseline: client DISCOVER xid bytes 0100ffff == predicted; verbatim console shows Received DHCP Offer/Ack ... (accepted); decode line adopts attacker yiaddr/siaddr, hostname pwn3d, rootfs 6.6.6.6:/pwn3d, swapfs 6.6.6.6:/swpwn, router; markers hostname ADOPTED / root NFS mount ADOPTED / default route ADOPTED / origin requested 0 times. test 4 baseline: panic bootpc: subnet mask len is 3. Fixed kernel: xid differs (karc4random), sniff+port9999 rejected with bootpc: reply not from server port 67, ignored; test 4 no panic; sniff+port67 still accepted (documented same-L2 residual)." }, "kernel_refs": [ "sys/vfs/nfs/bootp_subr.c:807-808", "sys/vfs/nfs/bootp_subr.c:831-852", "sys/vfs/nfs/bootp_subr.c:429-435", "sys/vfs/nfs/bootp_subr.c:1194-1196", "sys/vfs/nfs/bootp_subr.c:1538", "sys/vfs/nfs/bootp_subr.c:1341-1515", "sys/vfs/nfs/bootp_subr.c:1644-1666", "sys/vfs/nfs/bootp_subr.c:1142-1148", "sys/vfs/nfs/bootp_subr.c:1389-1391" ], "artifacts": [ "README.md", "VERDICT.md", "dfrig12_bootp.c", "build.sh", "run.sh", "run.log", "run.fixed.log", "panic.txt", "panic_console_full.txt", "fix_validation.log", "fix.diff", "fix_combined.diff", "build.log", "build_fixed.log", "env.txt", "manifest.json", "verdict.json" ] } |