From 3595599fa8360bb3c7afa7ee50c810b4a64106ea Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Mon, 27 Jan 2025 14:13:42 +0100 Subject: [PATCH] net: xdp: Disallow attaching device-bound programs in generic mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Device-bound programs are used to support RX metadata kfuncs. These kfuncs are driver-specific and rely on the driver context to read the metadata. This means they can't work in generic XDP mode. However, there is no check to disallow such programs from being attached in generic mode, in which case the metadata kfuncs will be called in an invalid context, leading to crashes. Fix this by adding a check to disallow attaching device-bound programs in generic mode. Fixes: 2b3486bc2d23 ("bpf: Introduce device-bound XDP programs") Reported-by: Marcus Wichelmann Closes: https://lore.kernel.org/r/dae862ec-43b5-41a0-8edf-46c59071cdda@hetzner-cloud.de Tested-by: Marcus Wichelmann Acked-by: Stanislav Fomichev Signed-off-by: Toke Høiland-Jørgensen Acked-by: Daniel Borkmann Acked-by: Martin KaFai Lau Link: https://patch.msgid.link/20250127131344.238147-1-toke@redhat.com Signed-off-by: Jakub Kicinski --- net/core/dev.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/core/dev.c b/net/core/dev.c index 07b2bb1ce64f..02cd75b512f9 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9924,6 +9924,10 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack NL_SET_ERR_MSG(extack, "Program bound to different device"); return -EINVAL; } + if (bpf_prog_is_dev_bound(new_prog->aux) && mode == XDP_MODE_SKB) { + NL_SET_ERR_MSG(extack, "Can't attach device-bound programs in generic mode"); + return -EINVAL; + } if (new_prog->expected_attach_type == BPF_XDP_DEVMAP) { NL_SET_ERR_MSG(extack, "BPF_XDP_DEVMAP programs can not be attached to a device"); return -EINVAL;