macsec: sync features on RTM_NEWLINK
Syzkaller managed to lock the lower device via ETHTOOL_SFEATURES:
netdev_lock include/linux/netdevice.h:2761 [inline]
netdev_lock_ops include/net/netdev_lock.h:42 [inline]
netdev_sync_lower_features net/core/dev.c:10649 [inline]
__netdev_update_features+0xcb1/0x1be0 net/core/dev.c:10819
netdev_update_features+0x6d/0xe0 net/core/dev.c:10876
macsec_notify+0x2f5/0x660 drivers/net/macsec.c:4533
notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
call_netdevice_notifiers net/core/dev.c:2281 [inline]
netdev_features_change+0x85/0xc0 net/core/dev.c:1570
__dev_ethtool net/ethtool/ioctl.c:3469 [inline]
dev_ethtool+0x1536/0x19b0 net/ethtool/ioctl.c:3502
dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:759
It happens because lower features are out of sync with the upper:
__dev_ethtool (real_dev)
netdev_lock_ops(real_dev)
ETHTOOL_SFEATURES
__netdev_features_change
netdev_sync_upper_features
disable LRO on the lower
if (old_features != dev->features)
netdev_features_change
fires NETDEV_FEAT_CHANGE
macsec_notify
NETDEV_FEAT_CHANGE
netdev_update_features (for each macsec dev)
netdev_sync_lower_features
if (upper_features != lower_features)
netdev_lock_ops(lower) # lower == real_dev
stuck
...
netdev_unlock_ops(real_dev)
Per commit af5f54b0ef9e ("net: Lock lower level devices when updating
features"), we elide the lock/unlock when the upper and lower features
are synced. Makes sure the lower (real_dev) has proper features after
the macsec link has been created. This makes sure we never hit the
situation where we need to sync upper flags to the lower.
| Source | ID | Title |
|---|---|---|
EUVD |
EUVD-2025-30856 | In the Linux kernel, the following vulnerability has been resolved: macsec: sync features on RTM_NEWLINK Syzkaller managed to lock the lower device via ETHTOOL_SFEATURES: netdev_lock include/linux/netdevice.h:2761 [inline] netdev_lock_ops include/net/netdev_lock.h:42 [inline] netdev_sync_lower_features net/core/dev.c:10649 [inline] __netdev_update_features+0xcb1/0x1be0 net/core/dev.c:10819 netdev_update_features+0x6d/0xe0 net/core/dev.c:10876 macsec_notify+0x2f5/0x660 drivers/net/macsec.c:4533 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] netdev_features_change+0x85/0xc0 net/core/dev.c:1570 __dev_ethtool net/ethtool/ioctl.c:3469 [inline] dev_ethtool+0x1536/0x19b0 net/ethtool/ioctl.c:3502 dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:759 It happens because lower features are out of sync with the upper: __dev_ethtool (real_dev) netdev_lock_ops(real_dev) ETHTOOL_SFEATURES __netdev_features_change netdev_sync_upper_features disable LRO on the lower if (old_features != dev->features) netdev_features_change fires NETDEV_FEAT_CHANGE macsec_notify NETDEV_FEAT_CHANGE netdev_update_features (for each macsec dev) netdev_sync_lower_features if (upper_features != lower_features) netdev_lock_ops(lower) # lower == real_dev stuck ... netdev_unlock_ops(real_dev) Per commit af5f54b0ef9e ("net: Lock lower level devices when updating features"), we elide the lock/unlock when the upper and lower features are synced. Makes sure the lower (real_dev) has proper features after the macsec link has been created. This makes sure we never hit the situation where we need to sync upper flags to the lower. |
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Wed, 14 Jan 2026 20:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Fri, 12 Dec 2025 19:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | NVD-CWE-noinfo | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* |
Wed, 24 Sep 2025 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Tue, 23 Sep 2025 16:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Tue, 23 Sep 2025 06:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: macsec: sync features on RTM_NEWLINK Syzkaller managed to lock the lower device via ETHTOOL_SFEATURES: netdev_lock include/linux/netdevice.h:2761 [inline] netdev_lock_ops include/net/netdev_lock.h:42 [inline] netdev_sync_lower_features net/core/dev.c:10649 [inline] __netdev_update_features+0xcb1/0x1be0 net/core/dev.c:10819 netdev_update_features+0x6d/0xe0 net/core/dev.c:10876 macsec_notify+0x2f5/0x660 drivers/net/macsec.c:4533 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] netdev_features_change+0x85/0xc0 net/core/dev.c:1570 __dev_ethtool net/ethtool/ioctl.c:3469 [inline] dev_ethtool+0x1536/0x19b0 net/ethtool/ioctl.c:3502 dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:759 It happens because lower features are out of sync with the upper: __dev_ethtool (real_dev) netdev_lock_ops(real_dev) ETHTOOL_SFEATURES __netdev_features_change netdev_sync_upper_features disable LRO on the lower if (old_features != dev->features) netdev_features_change fires NETDEV_FEAT_CHANGE macsec_notify NETDEV_FEAT_CHANGE netdev_update_features (for each macsec dev) netdev_sync_lower_features if (upper_features != lower_features) netdev_lock_ops(lower) # lower == real_dev stuck ... netdev_unlock_ops(real_dev) Per commit af5f54b0ef9e ("net: Lock lower level devices when updating features"), we elide the lock/unlock when the upper and lower features are synced. Makes sure the lower (real_dev) has proper features after the macsec link has been created. This makes sure we never hit the situation where we need to sync upper flags to the lower. | |
| Title | macsec: sync features on RTM_NEWLINK | |
| References |
|
Projects
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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-01-14T19:33:12.011Z
Reserved: 2025-04-16T07:20:57.144Z
Link: CVE-2025-39874
Updated: 2026-01-14T19:24:24.158Z
Status : Modified
Published: 2025-09-23T06:15:46.813
Modified: 2026-01-14T20:16:09.857
Link: CVE-2025-39874
OpenCVE Enrichment
Updated: 2025-09-23T16:03:18Z
EUVD