CVE-2024-56635

/// Technical description

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

net: avoid potential UAF in default_operstate()

syzbot reported an UAF in default_operstate() [1]

Issue is a race between device and netns dismantles.

After calling __rtnl_unlock() from netdev_run_todo(),

we can not assume the netns of each device is still alive.

Make sure the device is not in NETREG_UNREGISTERED state,

and add an ASSERT_RTNL() before the call to

__dev_get_by_index().

We might move this ASSERT_RTNL() in __dev_get_by_index()

in the future.

[1]

BUG: KASAN: slab-use-after-free in __dev_get_by_index+0x5d/0x110 net/core/dev.c:852

Read of size 8 at addr ffff888043eba1b0 by task syz.0.0/5339

CPU: 0 UID: 0 PID: 5339 Comm: syz.0.0 Not tainted 6.12.0-syzkaller-10296-gaaf20f870da0 #0

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014

Call Trace:

<TASK>

__dump_stack lib/dump_stack.c:94 [inline]

dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120

print_add

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References