Re: [PATCH] ipmr: validate IPv4 header length in reg_vif_xmit() and zero iphdr in ipmr_get_route()

From: Jakub Kicinski

Date: Sat Sep 19 2026 - 18:31:22 EST


On Sat, 19 Sep 2026 22:17:37 +0000 Hui Peng wrote:
> Fix two bugs in IPv4 multicast routing:
>
> 1. In reg_vif_xmit() (net/ipv4/ipmr.c), verify that the skb contains a
> full IPv4 header with ihl >= 5 before reading ip_hdr(skb) and passing
> the encapsulated PIM register packet to ipmr_cache_report().
> 2. In ipmr_get_route() and inet_rtm_getroute() (net/ipv4/route.c), zero-
> initialize the synthetic IPv4 header pushed onto the RTM_GETROUTE
> probe skb so uninitialized slab bytes in iph->ihl / iph->tos /
> iph->frag_off do not corrupt fib_multipath_hash() or
> ipmr_cache_alloc().
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Assisted-by: LLM
> Signed-off-by: Hui Peng <benquike@xxxxxxxxx>

Stop sending patches right now..

Please wait for feedback on patches you already sent before posting
_anything_ else.

You are allowed to send _revisions_ (new versions) of patches you
already submitted, but since you violated community guidelines by
dumping 40 patches at once you must not post any new networking
patch for the next two months.

Please *think* before you do things :/
--
pv-ban: 2mo