From: Eric Dumazet <edumazet@google.com> mainline inclusion from mainline-v7.2 commit cef51860becd9700217c81732ca1eb1ea6ed6fe1 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18331 CVE: CVE-2026-74743 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- macvlan devices inherit hard_header_len from lowerdev during macvlan_init(), but leave needed_headroom and needed_tailroom set to 0. When the underlying lowerdev requires extra headroom or tailroom for headers/trailers (e.g. macsec, ipsec, wireguard, tunnels, or veth with rx headroom), upper layers calculating packet headroom and tailroom fail to reserve sufficient space. This can result in reallocation overhead, skb headroom underflows, or KASAN slab-use-after-free crashes when dev_hard_header() / macvlan_hard_header() prepends header data or when lower devices append tailroom. Fix this by: 1. Inheriting needed_headroom and needed_tailroom from lowerdev in macvlan_init(). 2. Propagating needed_headroom and needed_tailroom updates to attached macvlans in macvlan_device_event() when receiving NETDEV_FEAT_CHANGE events. Fixes: b863ceb7ddce ("[NET]: Add macvlan driver") Reported-by: Tangxin Xie <xietangxin@h-partners.com> Closes: https://lore.kernel.org/netdev/CANn89i+1EW-sFNK8xoq98gMbPCeLS7e=+rs9gHfLg5Wj... Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Hangbin Liu <liuhangbin@kylinos.cn> Link: https://patch.msgid.link/20260806141938.287660-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Conflicts: drivers/net/macvlan.c [4.19 uses manual gso_max_size/gso_max_segs assignment instead of netif_inherit_tso_max() in macvlan_device_event() NETDEV_FEAT_CHANGE handler. The conflict is resolved by keeping 4.19's existing TSO inheritance and applying the new needed_headroom/needed_tailroom inheritance from the upstream patch.] Signed-off-by: JiangJieHua <jiangjiehua1@huawei.com> --- drivers/net/macvlan.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index 0f2a2e6705142..38e0386659aca 100644 --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -883,7 +883,8 @@ static int macvlan_init(struct net_device *dev) dev->gso_max_size = lowerdev->gso_max_size; dev->gso_max_segs = lowerdev->gso_max_segs; dev->hard_header_len = lowerdev->hard_header_len; - + dev->needed_headroom = lowerdev->needed_headroom; + dev->needed_tailroom = lowerdev->needed_tailroom; macvlan_set_lockdep_class(dev); vlan->pcpu_stats = netdev_alloc_pcpu_stats(struct vlan_pcpu_stats); @@ -1682,6 +1683,8 @@ static int macvlan_device_event(struct notifier_block *unused, list_for_each_entry(vlan, &port->vlans, list) { vlan->dev->gso_max_size = dev->gso_max_size; vlan->dev->gso_max_segs = dev->gso_max_segs; + vlan->dev->needed_headroom = dev->needed_headroom; + vlan->dev->needed_tailroom = dev->needed_tailroom; netdev_update_features(vlan->dev); } break; -- 2.33.8