CVE-2021-47082

/// Technical description

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

tun: avoid double free in tun_free_netdev

Avoid double free in tun_free_netdev() by moving the

dev->tstats and tun->security allocs to a new ndo_init routine

(tun_net_init()) that will be called by register_netdevice().

ndo_init is paired with the desctructor (tun_free_netdev()),

so if there's an error in register_netdevice() the destructor

will handle the frees.

BUG: KASAN: double-free or invalid-free in selinux_tun_dev_free_security+0x1a/0x20 security/selinux/hooks.c:5605

CPU: 0 PID: 25750 Comm: syz-executor416 Not tainted 5.16.0-rc2-syzk #1

Hardware name: Red Hat KVM, BIOS

Call Trace:

<TASK>

__dump_stack lib/dump_stack.c:88 [inline]

dump_stack_lvl+0x89/0xb5 lib/dump_stack.c:106

print_address_description.constprop.9+0x28/0x160 mm/kasan/report.c:247

kasan_report_invalid_free+0x55/0x80 mm/kasan/report.c:372

____kasan_slab_free mm/kasan/common.c:346 [inline]

__kasan_slab_free+0x107/0x120 mm/kasan/common.c:374

kasan_

/// 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