2.0 KiB
CVE-2024-50038
Description
In the Linux kernel, the following vulnerability has been resolved:netfilter: xtables: avoid NFPROTO_UNSPEC where neededsyzbot managed to call xt_cluster match via ebtables: WARNING: CPU: 0 PID: 11 at net/netfilter/xt_cluster.c:72 xt_cluster_mt+0x196/0x780 [..] ebt_do_table+0x174b/0x2a40Module registers to NFPROTO_UNSPEC, but it assumes ipv4/ipv6 packetprocessing. As this is only useful to restrict locally terminatingTCP/UDP traffic, register this for ipv4 and ipv6 family only.Pablo points out that this is a general issue, direct users of theset/getsockopt interface can call into targets/matches that were onlyintended for use with ip(6)tables.Check all UNSPEC matches and targets for similar issues:- matches and targets are fine except if they assume skb_network_header() is valid -- this is only true when called from inet layer: ip(6) stack pulls the ip/ipv6 header into linear data area.- targets that return XT_CONTINUE or other xtables verdicts must be restricted too, they are incompatbile with the ebtables traverser, e.g. EBT_CONTINUE is a completely different value than XT_CONTINUE.Most matches/targets are changed to register for NFPROTO_IPV4/IPV6, asthey are provided for use by ip(6)tables.The MARK target is also used by arptables, so register for NFPROTO_ARP too.While at it, bail out if connbytes fails to enable the correspondingconntrack family.This change passes the selftests in iptables.git.
POC
Reference
No PoCs from references.