net/mlx5e: RX, Fix generating skb from non-linear xdp_buff for legacy RQ

[ Upstream commit afd5ba577c10639f62e8120df67dc70ea4b61176 ]

XDP programs can release xdp_buff fragments when calling
bpf_xdp_adjust_tail(). The driver currently assumes the number of
fragments to be unchanged and may generate skb with wrong truesize or
containing invalid frags. Fix the bug by generating skb according to
xdp_buff after the XDP program runs.

BUG=b/469704838
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2025-40350 in the Linux kernel.

cos-patch: security-moderate
Fixes: ea5d49bdae8b ("net/mlx5e: Add XDP multi buffer support to the non-linear legacy RQ")
Link: https://patch.msgid.link/1760644540-899148-2-git-send-email-tariqt@nvidia.com
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Change-Id: I025909b6bdd4c49267debdfda29c6d915b367ec5
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/124487
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Angel Adetula <angeladetula@google.com>