From: Eric Dumazet <edumazet@google.com> mainline inclusion from mainline-v6.14-rc5 commit 27843ce6ba3d3122b65066550fe33fb8839f8aef category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBWVT4 CVE: CVE-2025-21891 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- syzbot found that ipvlan_process_v6_outbound() was assuming the IPv6 network header isis present in skb->head [1] Add the needed pskb_network_may_pull() calls for both IPv4 and IPv6 handlers. [1] BUG: KMSAN: uninit-value in __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47 __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47 ipv6_addr_type include/net/ipv6.h:555 [inline] ip6_route_output_flags_noref net/ipv6/route.c:2616 [inline] ip6_route_output_flags+0x51/0x720 net/ipv6/route.c:2651 ip6_route_output include/net/ip6_route.h:93 [inline] ipvlan_route_v6_outbound+0x24e/0x520 drivers/net/ipvlan/ipvlan_core.c:476 ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:491 [inline] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:541 [inline] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:605 [inline] ipvlan_queue_xmit+0xd72/0x1780 drivers/net/ipvlan/ipvlan_core.c:671 ipvlan_start_xmit+0x5b/0x210 drivers/net/ipvlan/ipvlan_main.c:223 __netdev_start_xmit include/linux/netdevice.h:5150 [inline] netdev_start_xmit include/linux/netdevice.h:5159 [inline] xmit_one net/core/dev.c:3735 [inline] dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3751 sch_direct_xmit+0x399/0xd40 net/sched/sch_generic.c:343 qdisc_restart net/sched/sch_generic.c:408 [inline] __qdisc_run+0x14da/0x35d0 net/sched/sch_generic.c:416 qdisc_run+0x141/0x4d0 include/net/pkt_sched.h:127 net_tx_action+0x78b/0x940 net/core/dev.c:5484 handle_softirqs+0x1a0/0x7c0 kernel/softirq.c:561 __do_softirq+0x14/0x1a kernel/softirq.c:595 do_softirq+0x9a/0x100 kernel/softirq.c:462 __local_bh_enable_ip+0x9f/0xb0 kernel/softirq.c:389 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline] __dev_queue_xmit+0x2758/0x57d0 net/core/dev.c:4611 dev_queue_xmit include/linux/netdevice.h:3311 [inline] packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3132 [inline] packet_sendmsg+0x93e0/0xa7e0 net/packet/af_packet.c:3164 sock_sendmsg_nosec net/socket.c:718 [inline] Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.") Reported-by: syzbot+93ab4a777bafb9d9f960@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/67b74f01.050a0220.14d86d.02d8.GAE@google.com/... Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Mahesh Bandewar <maheshb@google.com> Link: https://patch.msgid.link/20250220155336.61884-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Conflicts: drivers/net/ipvlan/ipvlan_core.c [conflicts due to not merge 0c30d6eedd1e ("ipvlan: Prepare ipvlan_process_v4_outbound() to future .flowi4_tos conversion.")] Signed-off-by: Wang Liang <wangliang74@huawei.com> --- drivers/net/ipvlan/ipvlan_core.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c index 4b561a2843fe..32442d58a3bb 100644 --- a/drivers/net/ipvlan/ipvlan_core.c +++ b/drivers/net/ipvlan/ipvlan_core.c @@ -431,20 +431,25 @@ struct ipvl_addr *ipvlan_addr_lookup(struct ipvl_port *port, void *lyr3h, static noinline_for_stack int ipvlan_process_v4_outbound(struct sk_buff *skb) { - const struct iphdr *ip4h = ip_hdr(skb); struct net_device *dev = skb->dev; struct net *net = dev_net(dev); - struct rtable *rt; int err, ret = NET_XMIT_DROP; + const struct iphdr *ip4h; + struct rtable *rt; struct flowi4 fl4 = { .flowi4_oif = dev->ifindex, - .flowi4_tos = RT_TOS(ip4h->tos), .flowi4_flags = FLOWI_FLAG_ANYSRC, .flowi4_mark = skb->mark, - .daddr = ip4h->daddr, - .saddr = ip4h->saddr, }; + if (!pskb_network_may_pull(skb, sizeof(struct iphdr))) + goto err; + + ip4h = ip_hdr(skb); + fl4.daddr = ip4h->daddr; + fl4.saddr = ip4h->saddr; + fl4.flowi4_tos = RT_TOS(ip4h->tos); + rt = ip_route_output_flow(net, &fl4, NULL); if (IS_ERR(rt)) goto err; @@ -503,6 +508,12 @@ static int ipvlan_process_v6_outbound(struct sk_buff *skb) struct net_device *dev = skb->dev; int err, ret = NET_XMIT_DROP; + if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr))) { + DEV_STATS_INC(dev, tx_errors); + kfree_skb(skb); + return ret; + } + err = ipvlan_route_v6_outbound(dev, skb); if (unlikely(err)) { dev->stats.tx_errors++; -- 2.34.1