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CVE-2024-46857

Disclosure Date: September 27, 2024 •
CVE-2024-46857
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Description

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

net/mlx5: Fix bridge mode operations when there are no VFs

Currently, trying to set the bridge mode attribute when numvfs=0 leads to a
crash:

bridge link set dev eth2 hwmode vepa

[ 168.967392] BUG: kernel NULL pointer dereference, address: 0000000000000030
[…]
[ 168.969989] RIP: 0010:mlx5_add_flow_rules+0x1f/0x300 [mlx5_core]
[…]
[ 168.976037] Call Trace:
[ 168.976188] <TASK>
[ 168.978620] _mlx5_eswitch_set_vepa_locked+0x113/0x230 [mlx5_core]
[ 168.979074] mlx5_eswitch_set_vepa+0x7f/0xa0 [mlx5_core]
[ 168.979471] rtnl_bridge_setlink+0xe9/0x1f0
[ 168.979714] rtnetlink_rcv_msg+0x159/0x400
[ 168.980451] netlink_rcv_skb+0x54/0x100
[ 168.980675] netlink_unicast+0x241/0x360
[ 168.980918] netlink_sendmsg+0x1f6/0x430
[ 168.981162] ____sys_sendmsg+0x3bb/0x3f0
[ 168.982155] ___sys_sendmsg+0x88/0xd0
[ 168.985036] __sys_sendmsg+0x59/0xa0
[ 168.985477] do_syscall_64+0x79/0x150
[ 168.987273] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 168.987773] RIP: 0033:0x7f8f7950f917

(esw->fdb_table.legacy.vepa_fdb is null)

The bridge mode is only relevant when there are multiple functions per
port. Therefore, prevent setting and getting this setting when there are no
VFs.

Note that after this change, there are no settings to change on the PF
interface using bridge link when there are no VFs, so the interface no
longer appears in the bridge link output.

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CVSS V3 Severity and Metrics
Base Score:
None
Impact Score:
Unknown
Exploitability Score:
Unknown
Vector:
Unknown
Attack Vector (AV):
Unknown
Attack Complexity (AC):
Unknown
Privileges Required (PR):
Unknown
User Interaction (UI):
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Scope (S):
Unknown
Confidentiality (C):
Unknown
Integrity (I):
Unknown
Availability (A):
Unknown

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
Linux 52c4beb79e09
Linux not down converted
Prerequisites
Unknown
Discovered By
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PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown

Vendors

  • Linux

Products

  • Linux
Technical Analysis