| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-38557: net/mlx5: Reload only IB representors upon lag disable/enable |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net/mlx5: Reload only IB representors upon lag disable/enable |
| |
| On lag disable, the bond IB device along with all of its |
| representors are destroyed, and then the slaves' representors get reloaded. |
| |
| In case the slave IB representor load fails, the eswitch error flow |
| unloads all representors, including ethernet representors, where the |
| netdevs get detached and removed from lag bond. Such flow is inaccurate |
| as the lag driver is not responsible for loading/unloading ethernet |
| representors. Furthermore, the flow described above begins by holding |
| lag lock to prevent bond changes during disable flow. However, when |
| reaching the ethernet representors detachment from lag, the lag lock is |
| required again, triggering the following deadlock: |
| |
| Call trace: |
| __switch_to+0xf4/0x148 |
| __schedule+0x2c8/0x7d0 |
| schedule+0x50/0xe0 |
| schedule_preempt_disabled+0x18/0x28 |
| __mutex_lock.isra.13+0x2b8/0x570 |
| __mutex_lock_slowpath+0x1c/0x28 |
| mutex_lock+0x4c/0x68 |
| mlx5_lag_remove_netdev+0x3c/0x1a0 [mlx5_core] |
| mlx5e_uplink_rep_disable+0x70/0xa0 [mlx5_core] |
| mlx5e_detach_netdev+0x6c/0xb0 [mlx5_core] |
| mlx5e_netdev_change_profile+0x44/0x138 [mlx5_core] |
| mlx5e_netdev_attach_nic_profile+0x28/0x38 [mlx5_core] |
| mlx5e_vport_rep_unload+0x184/0x1b8 [mlx5_core] |
| mlx5_esw_offloads_rep_load+0xd8/0xe0 [mlx5_core] |
| mlx5_eswitch_reload_reps+0x74/0xd0 [mlx5_core] |
| mlx5_disable_lag+0x130/0x138 [mlx5_core] |
| mlx5_lag_disable_change+0x6c/0x70 [mlx5_core] // hold ldev->lock |
| mlx5_devlink_eswitch_mode_set+0xc0/0x410 [mlx5_core] |
| devlink_nl_cmd_eswitch_set_doit+0xdc/0x180 |
| genl_family_rcv_msg_doit.isra.17+0xe8/0x138 |
| genl_rcv_msg+0xe4/0x220 |
| netlink_rcv_skb+0x44/0x108 |
| genl_rcv+0x40/0x58 |
| netlink_unicast+0x198/0x268 |
| netlink_sendmsg+0x1d4/0x418 |
| sock_sendmsg+0x54/0x60 |
| __sys_sendto+0xf4/0x120 |
| __arm64_sys_sendto+0x30/0x40 |
| el0_svc_common+0x8c/0x120 |
| do_el0_svc+0x30/0xa0 |
| el0_svc+0x20/0x30 |
| el0_sync_handler+0x90/0xb8 |
| el0_sync+0x160/0x180 |
| |
| Thus, upon lag enable/disable, load and unload only the IB representors |
| of the slaves preventing the deadlock mentioned above. |
| |
| While at it, refactor the mlx5_esw_offloads_rep_load() function to have |
| a static helper method for its internal logic, in symmetry with the |
| representor unload design. |
| |
| The Linux kernel CVE team has assigned CVE-2024-38557 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.15 with commit 598fe77df855feeeca9dfda2ffe622ac7724e5c3 and fixed in 6.6.33 with commit e93fc8d959e56092e2eca1e5511c2d2f0ad6807a |
| Issue introduced in 5.15 with commit 598fe77df855feeeca9dfda2ffe622ac7724e5c3 and fixed in 6.8.12 with commit f03c714a0fdd1f93101a929d0e727c28a66383fc |
| Issue introduced in 5.15 with commit 598fe77df855feeeca9dfda2ffe622ac7724e5c3 and fixed in 6.9.3 with commit 0f320f28f54b1b269a755be2e3fb3695e0b80b07 |
| Issue introduced in 5.15 with commit 598fe77df855feeeca9dfda2ffe622ac7724e5c3 and fixed in 6.10 with commit 0f06228d4a2dcc1fca5b3ddb0eefa09c05b102c4 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-38557 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/net/ethernet/mellanox/mlx5/core/eswitch.h |
| drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c |
| drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c |
| drivers/net/ethernet/mellanox/mlx5/core/lag/mpesw.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/e93fc8d959e56092e2eca1e5511c2d2f0ad6807a |
| https://git.kernel.org/stable/c/f03c714a0fdd1f93101a929d0e727c28a66383fc |
| https://git.kernel.org/stable/c/0f320f28f54b1b269a755be2e3fb3695e0b80b07 |
| https://git.kernel.org/stable/c/0f06228d4a2dcc1fca5b3ddb0eefa09c05b102c4 |
