* [PATCH 1/3] xfrm6: fix uninitialized saddr in xfrm6_get_saddr()
2026-02-20 9:41 [PATCH 0/3] pull request (net): ipsec 2026-02-20 Steffen Klassert
@ 2026-02-20 9:41 ` Steffen Klassert
2026-02-21 0:10 ` patchwork-bot+netdevbpf
2026-02-20 9:41 ` [PATCH 2/3] xfrm: skip templates check for packet offload tunnel mode Steffen Klassert
2026-02-20 9:41 ` [PATCH 3/3] xfrm: always flush state and policy upon NETDEV_UNREGISTER event Steffen Klassert
2 siblings, 1 reply; 5+ messages in thread
From: Steffen Klassert @ 2026-02-20 9:41 UTC (permalink / raw)
To: David Miller, Jakub Kicinski; +Cc: Herbert Xu, Steffen Klassert, netdev
From: Jiayuan Chen <jiayuan.chen@shopee.com>
xfrm6_get_saddr() does not check the return value of
ipv6_dev_get_saddr(). When ipv6_dev_get_saddr() fails to find a suitable
source address (returns -EADDRNOTAVAIL), saddr->in6 is left
uninitialized, but xfrm6_get_saddr() still returns 0 (success).
This causes the caller xfrm_tmpl_resolve_one() to use the uninitialized
address in xfrm_state_find(), triggering KMSAN warning:
=====================================================
BUG: KMSAN: uninit-value in xfrm_state_find+0x2424/0xa940
xfrm_state_find+0x2424/0xa940
xfrm_resolve_and_create_bundle+0x906/0x5a20
xfrm_lookup_with_ifid+0xcc0/0x3770
xfrm_lookup_route+0x63/0x2b0
ip_route_output_flow+0x1ce/0x270
udp_sendmsg+0x2ce1/0x3400
inet_sendmsg+0x1ef/0x2a0
__sock_sendmsg+0x278/0x3d0
__sys_sendto+0x593/0x720
__x64_sys_sendto+0x130/0x200
x64_sys_call+0x332b/0x3e70
do_syscall_64+0xd3/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Local variable tmp.i.i created at:
xfrm_resolve_and_create_bundle+0x3e3/0x5a20
xfrm_lookup_with_ifid+0xcc0/0x3770
=====================================================
Fix by checking the return value of ipv6_dev_get_saddr() and propagating
the error.
Fixes: a1e59abf8249 ("[XFRM]: Fix wildcard as tunnel source")
Reported-by: syzbot+e136d86d34b42399a8b1@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68bf1024.a70a0220.7a912.02c2.GAE@google.com/T/
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
net/ipv6/xfrm6_policy.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 1f19b6f14484..125ea9a5b8a0 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -57,6 +57,7 @@ static int xfrm6_get_saddr(xfrm_address_t *saddr,
struct dst_entry *dst;
struct net_device *dev;
struct inet6_dev *idev;
+ int err;
dst = xfrm6_dst_lookup(params);
if (IS_ERR(dst))
@@ -68,9 +69,11 @@ static int xfrm6_get_saddr(xfrm_address_t *saddr,
return -EHOSTUNREACH;
}
dev = idev->dev;
- ipv6_dev_get_saddr(dev_net(dev), dev, ¶ms->daddr->in6, 0,
- &saddr->in6);
+ err = ipv6_dev_get_saddr(dev_net(dev), dev, ¶ms->daddr->in6, 0,
+ &saddr->in6);
dst_release(dst);
+ if (err)
+ return -EHOSTUNREACH;
return 0;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 2/3] xfrm: skip templates check for packet offload tunnel mode
2026-02-20 9:41 [PATCH 0/3] pull request (net): ipsec 2026-02-20 Steffen Klassert
2026-02-20 9:41 ` [PATCH 1/3] xfrm6: fix uninitialized saddr in xfrm6_get_saddr() Steffen Klassert
@ 2026-02-20 9:41 ` Steffen Klassert
2026-02-20 9:41 ` [PATCH 3/3] xfrm: always flush state and policy upon NETDEV_UNREGISTER event Steffen Klassert
2 siblings, 0 replies; 5+ messages in thread
From: Steffen Klassert @ 2026-02-20 9:41 UTC (permalink / raw)
To: David Miller, Jakub Kicinski; +Cc: Herbert Xu, Steffen Klassert, netdev
From: Leon Romanovsky <leonro@nvidia.com>
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 <leonro@nvidia.com>
Reviewed-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
net/xfrm/xfrm_policy.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 62486f866975..5428185196a1 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -3801,8 +3801,8 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
struct xfrm_tmpl *tp[XFRM_MAX_DEPTH];
struct xfrm_tmpl *stp[XFRM_MAX_DEPTH];
struct xfrm_tmpl **tpp = tp;
+ int i, k = 0;
int ti = 0;
- int i, k;
sp = skb_sec_path(skb);
if (!sp)
@@ -3828,6 +3828,12 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
tpp = stp;
}
+ if (pol->xdo.type == XFRM_DEV_OFFLOAD_PACKET && sp == &dummy)
+ /* This policy template was already checked by HW
+ * and secpath was removed in __xfrm_policy_check2.
+ */
+ goto out;
+
/* For each tunnel xfrm, find the first matching tmpl.
* For each tmpl before that, find corresponding xfrm.
* Order is _important_. Later we will implement
@@ -3837,7 +3843,7 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
* verified to allow them to be skipped in future policy
* checks (e.g. nested tunnels).
*/
- for (i = xfrm_nr-1, k = 0; i >= 0; i--) {
+ for (i = xfrm_nr - 1; i >= 0; i--) {
k = xfrm_policy_ok(tpp[i], sp, k, family, if_id);
if (k < 0) {
if (k < -1)
@@ -3853,6 +3859,7 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
goto reject;
}
+out:
xfrm_pols_put(pols, npols);
sp->verified_cnt = k;
--
2.43.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 3/3] xfrm: always flush state and policy upon NETDEV_UNREGISTER event
2026-02-20 9:41 [PATCH 0/3] pull request (net): ipsec 2026-02-20 Steffen Klassert
2026-02-20 9:41 ` [PATCH 1/3] xfrm6: fix uninitialized saddr in xfrm6_get_saddr() Steffen Klassert
2026-02-20 9:41 ` [PATCH 2/3] xfrm: skip templates check for packet offload tunnel mode Steffen Klassert
@ 2026-02-20 9:41 ` Steffen Klassert
2 siblings, 0 replies; 5+ messages in thread
From: Steffen Klassert @ 2026-02-20 9:41 UTC (permalink / raw)
To: David Miller, Jakub Kicinski; +Cc: Herbert Xu, Steffen Klassert, netdev
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
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 <sd@queasysnail.net>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
net/xfrm/xfrm_device.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index 52ae0e034d29..550457e4c4f0 100644
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -544,6 +544,14 @@ static int xfrm_dev_down(struct net_device *dev)
return NOTIFY_DONE;
}
+static int xfrm_dev_unregister(struct net_device *dev)
+{
+ xfrm_dev_state_flush(dev_net(dev), dev, true);
+ xfrm_dev_policy_flush(dev_net(dev), dev, true);
+
+ return NOTIFY_DONE;
+}
+
static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
@@ -556,8 +564,10 @@ static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void
return xfrm_api_check(dev);
case NETDEV_DOWN:
- case NETDEV_UNREGISTER:
return xfrm_dev_down(dev);
+
+ case NETDEV_UNREGISTER:
+ return xfrm_dev_unregister(dev);
}
return NOTIFY_DONE;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 5+ messages in thread