IT

Tracker / CVE-2021-47223

CVE-2021-47223

Medium 5.5

In the Linux kernel, the following vulnerability has been resolved: net: bridge: fix vlan tunnel dst null pointer dereference This patch fixes a tunnel_dst null pointer dereference due to lockless access in the tunnel egress path. When deleting a vlan tunnel the tunnel_dst pointer is set to NULL without waiting a grace period (i.e. while it's still usable) and packets egressing are dereferencing it without checking. Use READ/WRITE_ONCE to annotate the lockless use of tunnel_id, use RCU for accessing tunnel_dst and make sure it is read only once and checked in the egress path. The dst is already properly RCU protected so we don't need to do anything fancy than to make sure tunnel_id and tunnel_dst are read only once and checked in the egress path.

Affected products and versions

linux linux_kernel
linux linux_kernel · 4.11 → 4.14.238
linux linux_kernel · 4.15 → 4.19.196
linux linux_kernel · 4.20 → 5.4.128
linux linux_kernel · 5.11 → 5.12.13
linux linux_kernel · 5.5 → 5.10.46

Analysis

This page is not indexable yet.Until it carries original analysis — what it actually exposes, how to check in two minutes whether a system was touched, what to do if it was — the page stays noindex. The database decides that, not the template.

References