6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
[ Upstream commit 3595599fa8360bb3c7afa7ee50c810b4a64106ea ]
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@xxxxxxxxxxxxxxxx>
Closes: https://lore.kernel.org/r/dae862ec-43b5-41a0-8edf-46c59071cdda@xxxxxxxxxxxxxxxx
Tested-by: Marcus Wichelmann <marcus.wichelmann@xxxxxxxxxxxxxxxx>
Acked-by: Stanislav Fomichev <sdf@xxxxxxxxxxx>
Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
Link: https://patch.msgid.link/20250127131344.238147-1-toke@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/core/dev.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/core/dev.c b/net/core/dev.c
index 69da7b009f8b9..479a3892f98c3 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9346,6 +9346,10 @@ 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;
--
2.39.5
