Subject: CVE-2024-42073: mlxsw: spectrum_buffers: Fix memory corruptions on Spectrum-4 systems

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

mlxsw: spectrum_buffers: Fix memory corruptions on Spectrum-4 systems

The following two shared buffer operations make use of the Shared Buffer
Status Register (SBSR):

 # devlink sb occupancy snapshot pci/0000:01:00.0
 # devlink sb occupancy clearmax pci/0000:01:00.0

The register has two masks of 256 bits to denote on which ingress /
egress ports the register should operate on. Spectrum-4 has more than
256 ports, so the register was extended by cited commit with a new
'port_page' field.

However, when filling the register's payload, the driver specifies the
ports as absolute numbers and not relative to the first port of the port
page, resulting in memory corruptions [1].

Fix by specifying the ports relative to the first port of the port page.

[1]
BUG: KASAN: slab-use-after-free in mlxsw_sp_sb_occ_snapshot+0xb6d/0xbc0
Read of size 1 at addr ffff8881068cb00f by task devlink/1566
[...]
Call Trace:
 <TASK>
 dump_stack_lvl+0xc6/0x120
 print_report+0xce/0x670
 kasan_report+0xd7/0x110
 mlxsw_sp_sb_occ_snapshot+0xb6d/0xbc0
 mlxsw_devlink_sb_occ_snapshot+0x75/0xb0
 devlink_nl_sb_occ_snapshot_doit+0x1f9/0x2a0
 genl_family_rcv_msg_doit+0x20c/0x300
 genl_rcv_msg+0x567/0x800
 netlink_rcv_skb+0x170/0x450
 genl_rcv+0x2d/0x40
 netlink_unicast+0x547/0x830
 netlink_sendmsg+0x8d4/0xdb0
 __sys_sendto+0x49b/0x510
 __x64_sys_sendto+0xe5/0x1c0
 do_syscall_64+0xc1/0x1d0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
[...]
Allocated by task 1:
 kasan_save_stack+0x33/0x60
 kasan_save_track+0x14/0x30
 __kasan_kmalloc+0x8f/0xa0
 copy_verifier_state+0xbc2/0xfb0
 do_check_common+0x2c51/0xc7e0
 bpf_check+0x5107/0x9960
 bpf_prog_load+0xf0e/0x2690
 __sys_bpf+0x1a61/0x49d0
 __x64_sys_bpf+0x7d/0xc0
 do_syscall_64+0xc1/0x1d0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 1:
 kasan_save_stack+0x33/0x60
 kasan_save_track+0x14/0x30
 kasan_save_free_info+0x3b/0x60
 poison_slab_object+0x109/0x170
 __kasan_slab_free+0x14/0x30
 kfree+0xca/0x2b0
 free_verifier_state+0xce/0x270
 do_check_common+0x4828/0xc7e0
 bpf_check+0x5107/0x9960
 bpf_prog_load+0xf0e/0x2690
 __sys_bpf+0x1a61/0x49d0
 __x64_sys_bpf+0x7d/0xc0
 do_syscall_64+0xc1/0x1d0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The Linux kernel CVE team has assigned CVE-2024-42073 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.17 with commit f8538aec88b4 and fixed in 6.1.97 with commit bfa86a96912f
	Issue introduced in 5.17 with commit f8538aec88b4 and fixed in 6.6.37 with commit 942901e0fc74
	Issue introduced in 5.17 with commit f8538aec88b4 and fixed in 6.9.8 with commit bf8781ede7bd
	Issue introduced in 5.17 with commit f8538aec88b4 and fixed in 6.10 with commit c28947de2bed

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-2024-42073
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/mlxsw/spectrum_buffers.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/bfa86a96912faa0b6142a918db88cc0c738a769e
	https://git.kernel.org/stable/c/942901e0fc74ad4b7992ef7ca9336e68d5fd6d36
	https://git.kernel.org/stable/c/bf8781ede7bd9a37c0fcabca78976e61300b5a1a
	https://git.kernel.org/stable/c/c28947de2bed40217cf256c5d0d16880054fcf13