6.1-stable review patch. If anyone has any objections, please let me know.
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From: Alexey Nepomnyashih sdl@nppct.ru
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 --- drivers/net/xen-netfront.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
--- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -985,20 +985,27 @@ static u32 xennet_run_xdp(struct netfron 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: