net/mlx5e: Harden uplink netdev access against device unbind
[ Upstream commit 6b4be64fd9fec16418f365c2d8e47a7566e9eba5 ]
The function mlx5_uplink_netdev_get() gets the uplink netdevice
pointer from mdev->mlx5e_res.uplink_netdev. However, the netdevice can
be removed and its pointer cleared when unbound from the mlx5_core.eth
driver. This results in a NULL pointer, causing a kernel panic.
BUG: unable to handle page fault for address: 0000000000001300
at RIP: 0010:mlx5e_vport_rep_load+0x22a/0x270 [mlx5_core]
Call Trace:
<TASK>
mlx5_esw_offloads_rep_load+0x68/0xe0 [mlx5_core]
esw_offloads_enable+0x593/0x910 [mlx5_core]
mlx5_eswitch_enable_locked+0x341/0x420 [mlx5_core]
mlx5_devlink_eswitch_mode_set+0x17e/0x3a0 [mlx5_core]
devlink_nl_eswitch_set_doit+0x60/0xd0
genl_family_rcv_msg_doit+0xe0/0x130
genl_rcv_msg+0x183/0x290
netlink_rcv_skb+0x4b/0xf0
genl_rcv+0x24/0x40
netlink_unicast+0x255/0x380
netlink_sendmsg+0x1f3/0x420
__sock_sendmsg+0x38/0x60
__sys_sendto+0x119/0x180
do_syscall_64+0x53/0x1d0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Ensure the pointer is valid before use by checking it for NULL. If it
is valid, immediately call netdev_hold() to take a reference, and
preventing the netdevice from being freed while it is in use.
BUG=b/449342316
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2025-39947 in the Linux kernel.
Fixes: 7a9fb35e8c3a ("net/mlx5e: Do not reload ethernet ports when changing eswitch mode")
Change-Id: I9c552a2b55f25a1c7c41db244069548006dd998a
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/1757939074-617281-2-git-send-email-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/113757
Reviewed-by: Kevin Berry <kpberry@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
4 files changed
