CVE-2022-48809

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net: fix a memleak when uncloning an skb dst and its metadata<br /> <br /> When uncloning an skb dst and its associated metadata, a new<br /> dst+metadata is allocated and later replaces the old one in the skb.<br /> This is helpful to have a non-shared dst+metadata attached to a specific<br /> skb.<br /> <br /> The issue is the uncloned dst+metadata is initialized with a refcount of<br /> 1, which is increased to 2 before attaching it to the skb. When<br /> tun_dst_unclone returns, the dst+metadata is only referenced from a<br /> single place (the skb) while its refcount is 2. Its refcount will never<br /> drop to 0 (when the skb is consumed), leading to a memory leak.<br /> <br /> Fix this by removing the call to dst_hold in tun_dst_unclone, as the<br /> dst+metadata refcount is already 1.