net: skbuff: propagate shared-frag marker through frag-transfer helpers
Replace 611.54.4's partial fix (which was a backport of Hyunwoo Kim's
v1 patch covering only __pskb_copy_fclone() and skb_try_coalesce())
with a backport of the upstream v3 patch:
https://lore.kernel.org/all/agW4vC0r8QOUKtRT@v4bel/
v3 also covers skb_shift() (the new hunk added in v2) and
skb_gro_receive() / skb_gro_receive_list() (the audit follow-up
suggested by Sultan Alsawaf in agVpIsaSherjHTYg@sultan-box).
All five sites moved frag descriptors between skbs without
propagating the SKBFL_SHARED_FRAG marker, so destinations could end
up referencing externally-owned or page-cache-backed pages while
reporting skb_has_shared_frag() as false. Combined with ESP-over-UDP
and UDP GRO, or any nf_dup_ipv4 / xt_TEE caller, this lets an
unprivileged user trigger in-place ESP decryption over root-owned
page-cache pages (CVE-2026-46300, "Fragnesia").
Tree-adapted: skb_gro_receive_list() is still a static helper in
net/ipv4/udp_offload.c on RHEL 9 (not promoted to a global GRO
helper in net/core/gro.c as in upstream v3); skb_shift() still uses
the open-coded skb->len -= shiftlen block instead of skb_len_add().
===================
The Kernel dist-git
===================
The kernel is maintained in a `source tree`_ rather than directly in dist-git.
The specfile is maintained as a `template`_ in the source tree along with a set
of build scripts to generate configurations, (S)RPMs, and to populate the
dist-git repository.
The `documentation`_ for the source tree covers how to contribute and maintain
the tree.
If you're looking for the downstream patch set it's available in the source
tree with "git log master..ark-patches" or
`online`_.
Each release in dist-git is tagged in the source repository so you can easily
check out the source tree for a build. The tags are in the format
name-version-release, but note release doesn't contain the dist tag since the
source can be built in different build roots (Fedora, CentOS, etc.)
.. _source tree: https://gitlab.com/cki-project/kernel-ark.git
.. _template: https://gitlab.com/cki-project/kernel-ark/-/blob/os-build/redhat/kernel.spec.template
.. _documentation: https://gitlab.com/cki-project/kernel-ark/-/wikis/home
.. _online: https://gitlab.com/cki-project/kernel-ark/-/commits/ark-patches
cbd86e4598