Subject: CVE-2024-26586: mlxsw: spectrum_acl_tcam: Fix stack corruption

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

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

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

mlxsw: spectrum_acl_tcam: Fix stack corruption

When tc filters are first added to a net device, the corresponding local
port gets bound to an ACL group in the device. The group contains a list
of ACLs. In turn, each ACL points to a different TCAM region where the
filters are stored. During forwarding, the ACLs are sequentially
evaluated until a match is found.

One reason to place filters in different regions is when they are added
with decreasing priorities and in an alternating order so that two
consecutive filters can never fit in the same region because of their
key usage.

In Spectrum-2 and newer ASICs the firmware started to report that the
maximum number of ACLs in a group is more than 16, but the layout of the
register that configures ACL groups (PAGT) was not updated to account
for that. It is therefore possible to hit stack corruption [1] in the
rare case where more than 16 ACLs in a group are required.

Fix by limiting the maximum ACL group size to the minimum between what
the firmware reports and the maximum ACLs that fit in the PAGT register.

Add a test case to make sure the machine does not crash when this
condition is hit.

[1]
Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: mlxsw_sp_acl_tcam_group_update+0x116/0x120
[...]
 dump_stack_lvl+0x36/0x50
 panic+0x305/0x330
 __stack_chk_fail+0x15/0x20
 mlxsw_sp_acl_tcam_group_update+0x116/0x120
 mlxsw_sp_acl_tcam_group_region_attach+0x69/0x110
 mlxsw_sp_acl_tcam_vchunk_get+0x492/0xa20
 mlxsw_sp_acl_tcam_ventry_add+0x25/0xe0
 mlxsw_sp_acl_rule_add+0x47/0x240
 mlxsw_sp_flower_replace+0x1a9/0x1d0
 tc_setup_cb_add+0xdc/0x1c0
 fl_hw_replace_filter+0x146/0x1f0
 fl_change+0xc17/0x1360
 tc_new_tfilter+0x472/0xb90
 rtnetlink_rcv_msg+0x313/0x3b0
 netlink_rcv_skb+0x58/0x100
 netlink_unicast+0x244/0x390
 netlink_sendmsg+0x1e4/0x440
 ____sys_sendmsg+0x164/0x260
 ___sys_sendmsg+0x9a/0xe0
 __sys_sendmsg+0x7a/0xc0
 do_syscall_64+0x40/0xe0
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

The Linux kernel CVE team has assigned CVE-2024-26586 to this issue.

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

	Issue introduced in 4.19 with commit c3ab435466d5 and fixed in 5.10.209 with commit 56750ea5d154
	Issue introduced in 4.19 with commit c3ab435466d5 and fixed in 5.15.148 with commit 348112522a35
	Issue introduced in 4.19 with commit c3ab435466d5 and fixed in 6.1.79 with commit 6fd24675188d
	Issue introduced in 4.19 with commit c3ab435466d5 and fixed in 6.6.14 with commit 2f5e15657404
	Issue introduced in 4.19 with commit c3ab435466d5 and fixed in 6.7.2 with commit a361c2c1da5d
	Issue introduced in 4.19 with commit c3ab435466d5 and fixed in 6.8 with commit 483ae90d8f97

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-2024-26586
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_acl_tcam.c
	tools/testing/selftests/drivers/net/mlxsw/spectrum-2/tc_flower.sh

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/56750ea5d15426b5f307554e7699e8b5f76c3182
	https://git.kernel.org/stable/c/348112522a35527c5bcba933b9fefb40a4f44f15
	https://git.kernel.org/stable/c/6fd24675188d354b1cad47462969afa2ab09d819
	https://git.kernel.org/stable/c/2f5e1565740490706332c06f36211d4ce0f88e62
	https://git.kernel.org/stable/c/a361c2c1da5dbb13ca67601cf961ab3ad68af383
	https://git.kernel.org/stable/c/483ae90d8f976f8339cf81066312e1329f2d3706