| Message ID | 20250127131344.238147-1-toke@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,1/2] net: xdp: Disallow attaching device-bound programs in generic mode | expand |
On 1/27/25 2:13 PM, Toke Høiland-Jørgensen wrote: > 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 <marcus.wichelmann@hetzner-cloud.de> > Closes: https://lore.kernel.org/r/dae862ec-43b5-41a0-8edf-46c59071cdda@hetzner-cloud.de > Tested-by: Marcus Wichelmann <marcus.wichelmann@hetzner-cloud.de> > Acked-by: Stanislav Fomichev <sdf@fomichev.me> > Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net>
On 1/27/25 5:13 AM, Toke Høiland-Jørgensen wrote: > 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. Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
diff --git a/net/core/dev.c b/net/core/dev.c index afa2282f2604..c1fa68264989 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;
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 <marcus.wichelmann@hetzner-cloud.de> Closes: https://lore.kernel.org/r/dae862ec-43b5-41a0-8edf-46c59071cdda@hetzner-cloud.de Tested-by: Marcus Wichelmann <marcus.wichelmann@hetzner-cloud.de> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> --- net/core/dev.c | 4 ++++ 1 file changed, 4 insertions(+)