In the Linux kernel, the following vulnerability has been resolved: eth: nfp: drop the replaced rule from the list when reprogramming fails

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

eth: nfp: drop the replaced rule from the list when reprogramming fails

nfp_net_fs_add() replaces an existing rule by deleting it from the
hardware, decrementing nn->fs.count and programming the new one. If
nfp_net_fs_add_hw() fails the old entry stays on nn->fs.list - only the
success path reaches list_replace() - so the list is one longer than
nn->fs.count, and it advertises a rule whose hardware entry has already
been torn down.

nn->fs.count is what ETHTOOL_GRXCLSRLCNT reports, so userspace then sizes
its buffer one entry short of what the GRXCLSRLALL walk wants to write.
That used to overwrite one u32 past the allocation; since the walk is
bounded it is a permanent -EMSGSIZE instead, as nothing ever resyncs the
counter.