kernel/linux.git/net/xfrm, branch v6.6.132

xfrm: Fix the usage of skb->sk

2026-04-02T11:07:16+00:00

[ Upstream commit 1620c88887b16940e00dbe57dd38c74eda9bad9e ] xfrm assumed to always have a full socket at skb->sk. This is not always true, so fix it by converting to a full socket before it is used. Signed-off-by: Steffen Klassert Reviewed-by: Eric Dumazet Stable-dep-of: 0c0eef8ccd24 ("esp: fix skb leak with espintcp and async crypto") Signed-off-by: Sasha Levin

xfrm: call xdo_dev_state_delete during state update

2026-04-02T11:07:16+00:00

[ Upstream commit 7d2fc41f91bc69acb6e01b0fa23cd7d0109a6a23 ] When we update an SA, we construct a new state and call xdo_dev_state_add, but never insert it. The existing state is updated, then we immediately destroy the new state. Since we haven't added it, we don't go through the standard state delete code, and we're skipping removing it from the device (but xdo_dev_state_free will get called when we destroy the temporary state). This is similar to commit c5d4d7d83165 ("xfrm: Fix deletion of offloaded SAs on failure."). Fixes: d77e38e612a0 ("xfrm: Add an IPsec hardware offloading API") Signed-off-by: Sabrina Dubroca Reviewed-by: Simon Horman Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin

xfrm: always flush state and policy upon NETDEV_UNREGISTER event

2026-03-04T12:20:59+00:00

[ Upstream commit 4efa91a28576054aae0e6dad9cba8fed8293aef8 ] syzbot is reporting that "struct xfrm_state" refcount is leaking. unregister_netdevice: waiting for netdevsim0 to become free. Usage count = 2 ref_tracker: netdev@ffff888052f24618 has 1/1 users at __netdev_tracker_alloc include/linux/netdevice.h:4400 [inline] netdev_tracker_alloc include/linux/netdevice.h:4412 [inline] xfrm_dev_state_add+0x3a5/0x1080 net/xfrm/xfrm_device.c:316 xfrm_state_construct net/xfrm/xfrm_user.c:986 [inline] xfrm_add_sa+0x34ff/0x5fa0 net/xfrm/xfrm_user.c:1022 xfrm_user_rcv_msg+0x58e/0xc00 net/xfrm/xfrm_user.c:3507 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550 xfrm_netlink_rcv+0x71/0x90 net/xfrm/xfrm_user.c:3529 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmsg+0x16d/0x220 net/socket.c:2678 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f This is because commit d77e38e612a0 ("xfrm: Add an IPsec hardware offloading API") implemented xfrm_dev_unregister() as no-op despite xfrm_dev_state_add() from xfrm_state_construct() acquires a reference to "struct net_device". I guess that that commit expected that NETDEV_DOWN event is fired before NETDEV_UNREGISTER event fires, and also assumed that xfrm_dev_state_add() is called only if (dev->features & NETIF_F_HW_ESP) != 0. Sabrina Dubroca identified steps to reproduce the same symptoms as below. echo 0 > /sys/bus/netdevsim/new_device dev=$(ls -1 /sys/bus/netdevsim/devices/netdevsim0/net/) ip xfrm state add src 192.168.13.1 dst 192.168.13.2 proto esp \ spi 0x1000 mode tunnel aead 'rfc4106(gcm(aes))' $key 128 \ offload crypto dev $dev dir out ethtool -K $dev esp-hw-offload off echo 0 > /sys/bus/netdevsim/del_device Like these steps indicate, the NETIF_F_HW_ESP bit can be cleared after xfrm_dev_state_add() acquired a reference to "struct net_device". Also, xfrm_dev_state_add() does not check for the NETIF_F_HW_ESP bit when acquiring a reference to "struct net_device". Commit 03891f820c21 ("xfrm: handle NETDEV_UNREGISTER for xfrm device") re-introduced the NETDEV_UNREGISTER event to xfrm_dev_event(), but that commit for unknown reason chose to share xfrm_dev_down() between the NETDEV_DOWN event and the NETDEV_UNREGISTER event. I guess that that commit missed the behavior in the previous paragraph. Therefore, we need to re-introduce xfrm_dev_unregister() in order to release the reference to "struct net_device" by unconditionally flushing state and policy. Reported-by: syzbot+881d65229ca4f9ae8c84@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=881d65229ca4f9ae8c84 Fixes: d77e38e612a0 ("xfrm: Add an IPsec hardware offloading API") Cc: Sabrina Dubroca Signed-off-by: Tetsuo Handa Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin

xfrm: skip templates check for packet offload tunnel mode

2026-03-04T12:20:58+00:00

[ Upstream commit 0a4524bc69882a4ddb235bb6b279597721bda197 ] In packet offload, hardware is responsible to check templates. The result of its operation is forwarded through secpath by relevant drivers. That secpath is actually removed in __xfrm_policy_check2(). In case packet is forwarded, this secpath is reset in RX, but pushed again to TX where policy is rechecked again against dummy secpath in xfrm_policy_ok(). Such situation causes to unexpected XfrmInTmplMismatch increase. As a solution, simply skip template mismatch check. Fixes: 600258d555f0 ("xfrm: delete intermediate secpath entry in packet offload mode") Signed-off-by: Leon Romanovsky Reviewed-by: Jianbo Liu Reviewed-by: Cosmin Ratiu Signed-off-by: Tariq Toukan Reviewed-by: Simon Horman Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin

xfrm: state: fix out-of-bounds read during lookup

2026-01-11T14:22:26+00:00

[ Upstream commit e952837f3ddb0ff726d5b582aa1aad9aa38d024d ] lookup and resize can run in parallel. The xfrm_state_hash_generation seqlock ensures a retry, but the hash functions can observe a hmask value that is too large for the new hlist array. rehash does: rcu_assign_pointer(net->xfrm.state_bydst, ndst) [..] net->xfrm.state_hmask = nhashmask; While state lookup does: h = xfrm_dst_hash(net, daddr, saddr, tmpl->reqid, encap_family); hlist_for_each_entry_rcu(x, net->xfrm.state_bydst + h, bydst) { This is only safe in case the update to state_bydst is larger than net->xfrm.xfrm_state_hmask (or if the lookup function gets serialized via state spinlock again). Fix this by prefetching state_hmask and the associated pointers. The xfrm_state_hash_generation seqlock retry will ensure that the pointer and the hmask will be consistent. The existing helpers, like xfrm_dst_hash(), are now unsafe for RCU side, add lockdep assertions to document that they are only safe for insert side. xfrm_state_lookup_byaddr() uses the spinlock rather than RCU. AFAICS this is an oversight from back when state lookup was converted to RCU, this lock should be replaced with RCU in a future patch. Reported-by: syzbot+5f9f31cb7d985f584d8e@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/CACT4Y+azwfrE3uz6A5ZErov5YN2LYBN5KrsymBerT36VU8qzBA@mail.gmail.com/ Diagnosed-by: Dmitry Vyukov Fixes: c2f672fc9464 ("xfrm: state lookup can be lockless") Signed-off-by: Florian Westphal Signed-off-by: Steffen Klassert [ Minor context change fixed ] Signed-off-by: Rajani Kantha <681739313@139.com> Signed-off-by: Greg Kroah-Hartman

xfrm: flush all states in xfrm_state_fini

2026-01-11T14:21:06+00:00

[ Upstream commit 42e42562c9cfcdacf000f1b42284a4fad24f8546 ] While reverting commit f75a2804da39 ("xfrm: destroy xfrm_state synchronously on net exit path"), I incorrectly changed xfrm_state_flush's "proto" argument back to IPSEC_PROTO_ANY. This reverts some of the changes in commit dbb2483b2a46 ("xfrm: clean up xfrm protocol checks"), and leads to some states not being removed when we exit the netns. Pass 0 instead of IPSEC_PROTO_ANY from both xfrm_state_fini xfrm6_tunnel_net_exit, so that xfrm_state_flush deletes all states. Fixes: 2a198bbec691 ("Revert "xfrm: destroy xfrm_state synchronously on net exit path"") Reported-by: syzbot+6641a61fe0e2e89ae8c5@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=6641a61fe0e2e89ae8c5 Tested-by: syzbot+6641a61fe0e2e89ae8c5@syzkaller.appspotmail.com Signed-off-by: Sabrina Dubroca Reviewed-by: Simon Horman Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin

xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added

2026-01-11T14:21:06+00:00

[ Upstream commit 10deb69864840ccf96b00ac2ab3a2055c0c04721 ] In commit b441cf3f8c4b ("xfrm: delete x->tunnel as we delete x"), I missed the case where state creation fails between full initialization (->init_state has been called) and being inserted on the lists. In this situation, ->init_state has been called, so for IPcomp tunnels, the fallback tunnel has been created and added onto the lists, but the user state never gets added, because we fail before that. The user state doesn't go through __xfrm_state_delete, so we don't call xfrm_state_delete_tunnel for those states, and we end up leaking the FB tunnel. There are several codepaths affected by this: the add/update paths, in both net/key and xfrm, and the migrate code (xfrm_migrate, xfrm_state_migrate). A "proper" rollback of the init_state work would probably be doable in the add/update code, but for migrate it gets more complicated as multiple states may be involved. At some point, the new (not-inserted) state will be destroyed, so call xfrm_state_delete_tunnel during xfrm_state_gc_destroy. Most states will have their fallback tunnel cleaned up during __xfrm_state_delete, which solves the issue that b441cf3f8c4b (and other patches before it) aimed at. All states (including FB tunnels) will be removed from the lists once xfrm_state_fini has called flush_work(&xfrm_state_gc_work). Reported-by: syzbot+999eb23467f83f9bf9bf@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=999eb23467f83f9bf9bf Fixes: b441cf3f8c4b ("xfrm: delete x->tunnel as we delete x") Signed-off-by: Sabrina Dubroca Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin

Revert "xfrm: destroy xfrm_state synchronously on net exit path"

2026-01-11T14:21:06+00:00

[ Upstream commit 2a198bbec6913ae1c90ec963750003c6213668c7 ] This reverts commit f75a2804da391571563c4b6b29e7797787332673. With all states (whether user or kern) removed from the hashtables during deletion, there's no need for synchronous destruction of states. xfrm6_tunnel states still need to have been destroyed (which will be the case when its last user is deleted (not destroyed)) so that xfrm6_tunnel_free_spi removes it from the per-netns hashtable before the netns is destroyed. This has the benefit of skipping one synchronize_rcu per state (in __xfrm_state_destroy(sync=true)) when we exit a netns. Signed-off-by: Sabrina Dubroca Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin

xfrm: delete x->tunnel as we delete x

2026-01-11T14:21:06+00:00

[ Upstream commit b441cf3f8c4b8576639d20c8eb4aa32917602ecd ] The ipcomp fallback tunnels currently get deleted (from the various lists and hashtables) as the last user state that needed that fallback is destroyed (not deleted). If a reference to that user state still exists, the fallback state will remain on the hashtables/lists, triggering the WARN in xfrm_state_fini. Because of those remaining references, the fix in commit f75a2804da39 ("xfrm: destroy xfrm_state synchronously on net exit path") is not complete. We recently fixed one such situation in TCP due to defered freeing of skbs (commit 9b6412e6979f ("tcp: drop secpath at the same time as we currently drop dst")). This can also happen due to IP reassembly: skbs with a secpath remain on the reassembly queue until netns destruction. If we can't guarantee that the queues are flushed by the time xfrm_state_fini runs, there may still be references to a (user) xfrm_state, preventing the timely deletion of the corresponding fallback state. Instead of chasing each instance of skbs holding a secpath one by one, this patch fixes the issue directly within xfrm, by deleting the fallback state as soon as the last user state depending on it has been deleted. Destruction will still happen when the final reference is dropped. A separate lockdep class for the fallback state is required since we're going to lock x->tunnel while x is locked. Fixes: 9d4139c76905 ("netns xfrm: per-netns xfrm_state_all list") Signed-off-by: Sabrina Dubroca Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin

xfrm: Prevent locally generated packets from direct output in tunnel mode

2025-12-01T10:41:45+00:00

[ Upstream commit 59630e2ccd728703cc826e3a3515d70f8c7a766c ] Add a check to ensure locally generated packets (skb->sk != NULL) do not use direct output in tunnel mode, as these packets require proper L2 header setup that is handled by the normal XFRM processing path. Fixes: 5eddd76ec2fd ("xfrm: fix tunnel mode TX datapath in packet offload mode") Signed-off-by: Jianbo Liu Reviewed-by: Leon Romanovsky Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin