Описание
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ
XDP multi-buf programs can modify the layout of the XDP buffer when the
program calls bpf_xdp_pull_data() or bpf_xdp_adjust_tail(). The
referenced commit in the fixes tag corrected the assumption in the mlx5
driver that the XDP buffer layout doesn't change during a program
execution. However, this fix introduced another issue: the dropped
fragments still need to be counted on the driver side to avoid page
fragment reference counting issues.
Such issue can be observed with the
test_xdp_native_adjst_tail_shrnk_data selftest when using a payload of
3600 and shrinking by 256 bytes (an upcoming selftest patch): the last
fragment gets released by the XDP code but doesn't get tracked by the
driver. This results in a negative pp_ref_count during page release and
the following splat:
WARNING: include/net/page_pool/helpers.h:297 at mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core], CPU#12: ip/3137
Modules linked in: [...]
CPU: 12 UID: 0 PID: 3137 Comm: ip Not tainted 6.19.0-rc3+ #12 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
RIP: 0010:mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core]
[...]
Call Trace:
mlx5e_dealloc_rx_wqe+0xcb/0x1a0 [mlx5_core]
mlx5e_free_rx_descs+0x7f/0x110 [mlx5_core]
mlx5e_close_rq+0x50/0x60 [mlx5_core]
mlx5e_close_queues+0x36/0x2c0 [mlx5_core]
mlx5e_close_channel+0x1c/0x50 [mlx5_core]
mlx5e_close_channels+0x45/0x80 [mlx5_core]
mlx5e_safe_switch_params+0x1a5/0x230 [mlx5_core]
mlx5e_change_mtu+0xf3/0x2f0 [mlx5_core]
netif_set_mtu_ext+0xf1/0x230
do_setlink.isra.0+0x219/0x1180
rtnl_newlink+0x79f/0xb60
rtnetlink_rcv_msg+0x213/0x3a0
netlink_rcv_skb+0x48/0xf0
netlink_unicast+0x24a/0x350
netlink_sendmsg+0x1ee/0x410
__sock_sendmsg+0x38/0x60
____sys_sendmsg+0x232/0x280
___sys_sendmsg+0x78/0xb0
__sys_sendmsg+0x5f/0xb0
[...]
do_syscall_64+0x57/0xc50
This patch fixes the issue by doing page frag counting on all the
original XDP buffer fragments for all relevant XDP actions (XDP_TX ,
XDP_REDIRECT and XDP_PASS). This is basically reverting to the original
counting before the commit in the fixes tag.
As frag_page is still pointing to the original tail, the nr_frags
parameter to xdp_update_skb_frags_info() needs to be calculated
in a different way to reflect the new nr_frags.
A flaw was found in the Linux kernel's mlx5e driver. When using eXpress Data Path (XDP) multi-buffer programs, an attacker could manipulate the XDP buffer layout. This manipulation leads to incorrect tracking of page fragments, causing a critical error in memory management. The issue can result in a system crash or denial of service.
Отчет
Red Hat acknowledges the upstream Linux kernel correction for «net/mlx5e» as described in COMMENT_ZERO. Fixes are delivered through standard kernel errata for supported products. Operational exposure depends on whether this subsystem or driver is active in your configuration.
Меры по смягчению последствий
To mitigate this issue, prevent the mlx5_core module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected |
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Дополнительная информация
Статус:
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ XDP multi-buf programs can modify the layout of the XDP buffer when the program calls bpf_xdp_pull_data() or bpf_xdp_adjust_tail(). The referenced commit in the fixes tag corrected the assumption in the mlx5 driver that the XDP buffer layout doesn't change during a program execution. However, this fix introduced another issue: the dropped fragments still need to be counted on the driver side to avoid page fragment reference counting issues. Such issue can be observed with the test_xdp_native_adjst_tail_shrnk_data selftest when using a payload of 3600 and shrinking by 256 bytes (an upcoming selftest patch): the last fragment gets released by the XDP code but doesn't get tracked by the driver. This results in a negative pp_ref_count during page release and the following splat: WARNING: include/net/page_pool/helpers.h:297 at mlx5e_page_release_fragmented.isra...
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ XDP multi-buf programs can modify the layout of the XDP buffer when the program calls bpf_xdp_pull_data() or bpf_xdp_adjust_tail(). The referenced commit in the fixes tag corrected the assumption in the mlx5 driver that the XDP buffer layout doesn't change during a program execution. However, this fix introduced another issue: the dropped fragments still need to be counted on the driver side to avoid page fragment reference counting issues. Such issue can be observed with the test_xdp_native_adjst_tail_shrnk_data selftest when using a payload of 3600 and shrinking by 256 bytes (an upcoming selftest patch): the last fragment gets released by the XDP code but doesn't get tracked by the driver. This results in a negative pp_ref_count during page release and the following splat: WARNING: include/net/page_pool/helpers.h:297 at mlx5e_page_release_fragmented.i
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ XDP multi-buf programs can modify the layout of the XDP buffer when the program calls bpf_xdp_pull_data() or bpf_xdp_adjust_tail(). The referenced commit in the fixes tag corrected the assumption in the mlx5 driver that the XDP buffer layout doesn't change during a program execution. However, this fix introduced another issue: the dropped fragments still need to be counted on the driver side to avoid page fragment reference counting issues. Such issue can be observed with the test_xdp_native_adjst_tail_shrnk_data selftest when using a payload of 3600 and shrinking by 256 bytes (an upcoming selftest patch): the last fragment gets released by the XDP code but doesn't get tracked by the driver. This results in a negative pp_ref_count during page release and the following splat: WARNING: include/net/page_pool/helpers.h:297 at mlx5e_page_release_fragmente...
5.5 Medium
CVSS3