From: Alexey Nepomnyashih <sdl@nppct.ru> stable inclusion from stable-v6.6.89 commit cefd8a2e2de46209ce66e6d30c237eb59b6c5bfa category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IC6BM5 CVE: CVE-2025-37820 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit cc3628dcd851ddd8d418bf0c897024b4621ddc92 upstream. The function xdp_convert_buff_to_frame() may return NULL if it fails to correctly convert the XDP buffer into an XDP frame due to memory constraints, internal errors, or invalid data. Failing to check for NULL may lead to a NULL pointer dereference if the result is used later in processing, potentially causing crashes, data corruption, or undefined behavior. On XDP redirect failure, the associated page must be released explicitly if it was previously retained via get_page(). Failing to do so may result in a memory leak, as the pages reference count is not decremented. Cc: stable@vger.kernel.org # v5.9+ Fixes: 6c5aa6fc4def ("xen networking: add basic XDP support for xen-netfront") Signed-off-by: Alexey Nepomnyashih <sdl@nppct.ru> Link: https://patch.msgid.link/20250417122118.1009824-1-sdl@nppct.ru Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Wang Liang <wangliang74@huawei.com> --- drivers/net/xen-netfront.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index bcb5651f18e0..0115f8f5b724 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -985,20 +985,27 @@ static u32 xennet_run_xdp(struct netfront_queue *queue, struct page *pdata, act = bpf_prog_run_xdp(prog, xdp); switch (act) { case XDP_TX: - get_page(pdata); xdpf = xdp_convert_buff_to_frame(xdp); + if (unlikely(!xdpf)) { + trace_xdp_exception(queue->info->netdev, prog, act); + break; + } + get_page(pdata); err = xennet_xdp_xmit(queue->info->netdev, 1, &xdpf, 0); - if (unlikely(!err)) + if (unlikely(err <= 0)) { + if (err < 0) + trace_xdp_exception(queue->info->netdev, prog, act); xdp_return_frame_rx_napi(xdpf); - else if (unlikely(err < 0)) - trace_xdp_exception(queue->info->netdev, prog, act); + } break; case XDP_REDIRECT: get_page(pdata); err = xdp_do_redirect(queue->info->netdev, xdp, prog); *need_xdp_flush = true; - if (unlikely(err)) + if (unlikely(err)) { trace_xdp_exception(queue->info->netdev, prog, act); + xdp_return_buff(xdp); + } break; case XDP_PASS: case XDP_DROP: -- 2.34.1