CVE-2021-47224 Information

Description

In the Linux kernel the following vulnerability has been resolved:

net: ll_temac: Make sure to free skb when it is completely used

With the skb pointer piggy-backed on the TX BD we have a simple and efficient way to free the skb buffer when the frame has been transmitted. But in order to avoid freeing the skb while there are still fragments from the skb in use we need to piggy-back on the TX BD of the skb not the first.

Without this we are doing use-after-free on the DMA side when the first BD of a multi TX BD packet is seen as completed in xmit_done and the remaining BDs are still being processed.

Reference

https://git.kernel.org/stable/c/6d120ab4dc39a543c6b63361e1d0541c382900a3 https://git.kernel.org/stable/c/019ab7d044d0ebf97e1236bb8935b7809be92358 https://git.kernel.org/stable/c/e8afe05bd359ebe12a61dbdc94c06c00ea3e8d4b https://git.kernel.org/stable/c/6aa32217a9a446275440ee8724b1ecaf1838df47