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 Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Xiang Mei --- v2: Add Kyle as "Reported-by" drivers/net/geneve.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 715180c3a1b3..d0dc5d6c46df 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -948,13 +948,13 @@ 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))) -- 2.43.0