Bug 2400615 (CVE-2025-39908)

Summary: CVE-2025-39908 kernel: net: dev_ioctl: take ops lock in hwtstamp lower paths
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-10-01 08:02:40 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: dev_ioctl: take ops lock in hwtstamp lower paths

ndo hwtstamp callbacks are expected to run under the per-device ops
lock. Make the lower get/set paths consistent with the rest of ndo
invocations.

Kernel log:
WARNING: CPU: 13 PID: 51364 at ./include/net/netdev_lock.h:70 __netdev_update_features+0x4bd/0xe60
...
RIP: 0010:__netdev_update_features+0x4bd/0xe60
...
Call Trace:
<TASK>
netdev_update_features+0x1f/0x60
mlx5_hwtstamp_set+0x181/0x290 [mlx5_core]
mlx5e_hwtstamp_set+0x19/0x30 [mlx5_core]
dev_set_hwtstamp_phylib+0x9f/0x220
dev_set_hwtstamp_phylib+0x9f/0x220
dev_set_hwtstamp+0x13d/0x240
dev_ioctl+0x12f/0x4b0
sock_ioctl+0x171/0x370
__x64_sys_ioctl+0x3f7/0x900
? __sys_setsockopt+0x69/0xb0
do_syscall_64+0x6f/0x2e0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
...
</TASK>
....
---[ end trace 0000000000000000 ]---

Note that the mlx5_hwtstamp_set and mlx5e_hwtstamp_set functions shown
in the trace come from an in progress patch converting the legacy ioctl
to ndo_hwtstamp_get/set and are not present in mainline.
Comment 1 Alexander B 2025-10-02 11:24:15 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025100109-CVE-2025-39908-5d27@gregkh/T