From: Xiang Mei Date: Thu, 18 Jun 2026 03:26:21 +0000 (-0700) Subject: geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint X-Git-Tag: v7.2-rc1~29^2~25 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=2651c174445884ac9e85622aeade9c1f7b98d8e5;p=thirdparty%2Flinux.git geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint geneve_gro_receive() reads the GRO hint through geneve_sk_gro_hint_off(), which honours it only when the socket enabled IFLA_GENEVE_GRO_HINT (gs->gro_hint). geneve_gro_complete() instead calls the low-level geneve_opt_gro_hint_off() and acts on the hint unconditionally. On a tunnel without the hint, receive aggregates the frames as plain ETH_P_TEB while complete still honours an attacker-supplied hint option: it inflates gh_len by gro_hint->nested_hdr_len (u8) and redirects the dispatch type, so the inner gro_complete handler runs at nhoff + gh_len, an offset receive never pulled nor validated, reading out of bounds of the skb head: BUG: KASAN: slab-out-of-bounds in ipv6_gro_complete (net/ipv6/ip6_offload.c:196) Read of size 1 at addr ffff88800fe91980 by task exploit/153 ipv6_gro_complete (net/ipv6/ip6_offload.c:196) geneve_gro_complete (drivers/net/geneve.c:965) udp_gro_complete (net/ipv4/udp_offload.c:940) inet_gro_complete (net/ipv4/af_inet.c:1621) __gro_flush (net/core/gro.c:306) Gate the complete path on gs->gro_hint too via geneve_sk_gro_hint_off(), so both paths agree. Tunnels that enable the hint are unaffected. Fixes: fd0dd796576e ("geneve: use GRO hint option in the RX path") Reported-by: Weiming Shi Reported-by: Kyle Zeng Signed-off-by: Xiang Mei Link: https://patch.msgid.link/20260618032622.484720-1-xmei5@asu.edu Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 9afff7bcaa0b3..7cf7aaac8ee1a 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -954,13 +954,13 @@ static int geneve_gro_complete(struct sock *sk, struct sk_buff *skb, struct genevehdr *gh; struct packet_offload *ptype; __be16 type; - int gh_len; + unsigned int gh_len; int err = -ENOSYS; gh = (struct genevehdr *)(skb->data + nhoff); gh_len = geneve_hlen(gh); type = gh->proto_type; - geneve_opt_gro_hint_off(gh, &type, &gh_len); + geneve_sk_gro_hint_off(sk, gh, &type, &gh_len); /* since skb->encapsulation is set, eth_gro_complete() sets the inner mac header */ if (likely(type == htons(ETH_P_TEB)))